Manipulation for out-of-season breeding in Spanish goats

T. Wuliji, A. L. Goetsch, A. Litherland, T. Sahlu, R. Puchala, and L. J. Dawson

E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK

The manipulation of seasonal breeding in goats could improve profitability of meat goat production by producing out-of-season meat kids for Christmas festive markets and increasing the number of kids born per female. Therefore, the objective of this experiment was to evaluate means of manipulating breeding season. Three Spanish bucks were conditioned for 2 mo of long-day photoperiod (16 h light:8 h dark) starting January 19, 1999, followed by a single dose of a continuous-release melatonin implant (18 mg, Regulin, Schering Pty. Ltd). Eighty Spanish does (15 2 years of age and 65 yearling doelings) were allotted to three treatments of zero, melatonin implant, and oral administration of melatonin (Sigma Chemical Co., St. Louis, MO). Half of each melatonin group also received three pellets of bromocryptine mesylate (215 mg) implants (Innovative Research of America, Sarasota, FL). Therefore, treatments were: control (C), melatonin implant (MI), melatonin and bromocryptine mesylate implants (MIB), melatonin oral delivery (MO, 3 mg/d), and melatonin oral delivery and bromocryptine mesylate implant (MOB). At the end of treatments (April 13), does were randomized and bred in three single-sire groups for two estrus cycles (34 d). The number of does bred was 14, 14, 14, 14, and 15; number of does pregnant at ultrasonographic scanning was 5, 10, 12, 12, and 11; number of does kidded was 5, 10, 11, 8, and 8; and number of kids born was 8, 18, 18, 13, and 18 for C, MI, MIB, MO, and MOB, respectively. There was no difference among treatments in number of does bred, whereas melatonin-treated groups had a greater (P < .05) number of does that kidded and number of kids born. In conclusion, melatonin regardless of delivery mode increased the number of does kidding in the late summer/early fall.

Broiler litter and urea-treated wheat straw as feedstuffs for Alpine doelings

G. Animut1, R.C. Merkel2, G. Abebe3, T. Sahlu2, and A.L. Goetsch2

1Alemaya University of Agriculture, Dire Dawa, Ethiopia
2E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK
3Awassa College of Agriculture, Awassa, Ethiopia

Thirty-two Alpine doelings (15 wk of age, 12 ± 2.05 kg) were randomly allocated to four treatments to evaluate the use of deep-stacked broiler litter (BL) and urea-treated wheat straw (UWS) as feedstuffs. In all treatments, UWS or untreated wheat straw (WS) was fed for ad libitum consumption along with a concentrate supplement fed at a prescribed percentage of BW. Treatments were: U - a corn-based concentrate (1.3% N) fed at 1.5% BW with UWS (2.1% N); S - a corn:soybean meal concentrate (3.2% N) fed at 1.9% BW with WS (.5% N); LL - a corn:BL concentrate (2.3% N, BL at .8% BW) fed at 2.2% BW with WS; and HL - a corn:BL concentrate (2.7% N, BL at 1.6% BW) fed at 3.0% BW with WS. Animals were housed individually and fed once daily. Body weights were determined at 2-wk intervals prior to daily feeding during the 12-wk trial; ADG was calculated by regression. HL doelings consumed a greater amount of DM (P < .05) throughout the trial than LL, S and U animals (54.7, 45.0, 35.9, and 36.4 kg, respectively, SE = 11.64). ADG did not vary among treatments (P > .05) and was 66, 63, 70, and 61 g/d (SE = 7.1) for HL, LL, S, and U, respectively. Feed conversion efficiency was lower (P < .05) for HL and LL than for S doelings, whereas U doelings had a feed conversion efficiency similar to S and LL but greater than HL (P < .05) (170, 145, 122, and 103 g gain/kg DMI for S, U, LL, and HL, respectively; SE = 11.6). Results indicate that both BL and UWS can be used as feedstuffs for replacement Alpine doeling growth during the early post-weaning period. The possibility of using modified crop residues and animal by-products as feedstuffs for goats is very important in countries such as Ethiopia where the availability and use of more conventional feedstuffs is limited.

Current Perspectives in Using Goats for Vegetation Management

S. P. Hart

E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK 73050

Although an ever-increasing body of research data has documented the usefulness of goats for controlling brushy and weedy species such as shinnery oak, blackjack and post oak, leafy spurge, sericea lespedeza and many others, this technology remains sorely underutilized. Environmental concerns and the increased costs of chemical and mechanical control methods provide greater opportunities to utilize biological control methods for brush and weeds to include goats. Goats have an advantage over other biological control methods in that they can profitably convert brush and weeds into a saleable product and they can be grazed concurrently with cattle. In addition, goats release the plant nutrients, especially N and P, that are tied up in brush and weeds to enable reestablishment of grassy species. The foremost limitation to using goats for brush and weed control is the social stigma cattlemen attach to goats. However, extreme economic pressures from invasive brush and weeds provide an incentive to overcome this prejudice. Extension demonstrations that provide visual proof of efficacy of control by goats are also valuable. The lack of an infrastructure (animal markets, source of large numbers of adapted animals, producer experience and knowledge base) to support goat enterprises is a serious constraint which is gradually being overcome by goat industry expansion. Suitable goat production systems need to be developed for specific environments. This involves the modification of existing knowledge, especially in regard to kidding date, parasite and predator control, electric fencing and marketing strategy. The lack of economic data and enterprise budgets is also a constraint. Further research is needed to collect economic data, and to develop stocking rate criteria and production systems to support the use of goats for biological brush and weed control.

Nutrition for the High Producing Dairy Doe

S. P. Hart

E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK. 73050.

Before milk can be processed, it has to be produced by the animal and nutrients are a major input both in quantity and cost for milk production. The lactating animal is efficient at mitigating most, but not all, of the effects of widely differing diets on milk quality. The NRC report on Nutrient Requirements of Goats was published nearly 20 years ago; hence, a considerable body of research remains to be considered in nutrition recommendations for goats. The greatest limitation in knowledge of feeding goats is an inability to predict intake. The concentration of nutrients required in the diet is affected by intake level. Dairy goats often consume 6% of their body weight as DM and may exceed 8%. Due to the high levels of intake, the minimum dietary CP concentration may be lower than for dairy cattle. Several studies have shown the efficacy of bypass fat sources for increasing energy intake and milk production in dairy goats. Three studies have failed to demonstrate effects of bypass protein on milk production of goats, in contrast to well-documented improvements with dairy cows. Limited evidence indicates that goats have a faster rate of passage of digesta which would increase ruminal escape of protein and ruminal microbial protein production, thereby mitigating protein as a limiting nutrient. Very little work has been done on the utilization of feed byproducts in goat diets. The use of a negative ion balance in the diet for prevention of milk fever has not been studied in goats. Beyond calcium and phosphorus requirements, there has been little mineral research with goats. Overall, our limits in knowledge of goat nutrition force us to extrapolate from other species, which may and may not be appropriate and to rely on anecdotal information. A current project to develop nutrient requirement expressions from recent goat research may improve our ability to feed goats and help identify critical research needs, which is quite important due to limited support for goat research.

Body weight, fleece weight, and wool characteristics of Texel × Romney crossbred hoggets

T. Wuliji1 and K. G. Dodds2

1E (Kika) de la Garza Research Institute for Goats, Langston University, Langston, OK
2AgResearch, Invermay Agricultural Centre, Mosgiel, New Zealand

Live weight, fleece weight and wool characteristics of crossbred hoggets comprising seven genotypes were analyzed for control Romney (CR), Romney selected for high fleece weight (HR), Texel x Romney (TRF1), Texel x Romney intercross (TRF2), Texel x [Texel x Romney] (TTR), [Texel x Romney] x Romney (TRR) and [Poll Dorset x Romney] x [Texel x Romney] (DTR). Birth-rearing rank, birth weight (BW), weaning weight (WW), spring weight (SW), greasy fleece weight (GF) were recorded. Wool samples were measured for oven dry yield (%), bulk, fiber diameter, wool brightness (Y) and yellowness (Y-Z). Data were analyzed by residual maximum likelihood (REML), with genotype, year, sex, birth rearing rank and age of dam included as fixed effects, birth date as a covariate and sire as a random effect. Crossbred genotypes had 13 - 23% higher fleece weight than CR (P<0.05) but fleece weights were lower than HR (P<0.05). Wool bulk was increased by 22 - 37% and wool fibre diameter was reduced by about 1.5 m in most crossbred genotypes compared to Romneys (Table 1).Table 1. Genotype least squares means for live weight, fleece weight and wool characteristics.

Geno-type No. BW

(kg)

WW

(kg)

SW

(kg)

GF

(kg)

Yield

(%)

Bulk

(cm3g)

FD

(m)

Y-Z
CR 181 4.3a 21.5a 45.2a 2.31b 65.6d 23.7a 32.5bc 4.8
HR 136 4.5ab 25.0cd 50.2b 3.26e 64.7cd 25.7b 34.0c 4.8
TRR 470 4.9cd 23.2b 50.8b 2.85d 62.6b 26.4b 32.6b 4.9
TRF1 233 5.0d 25.8d 53.6c 2.66c 63.7bc 29.1c 32.5b 5.1
TRF2 84 4.7bcd 25.9d 54.2c 2.71cd 60.9a 30.0c 32.6abc 5.1
DTR 90 4.6abc 26.1d 55.3c 2.62c 62.7b 32.5d 32.5ab 4.4
TTR 65 4.5ab 24.2bc 48.9b 2.06a 63.3abc 29.0c 30.8a 5.1
Mean SED 0.2 0.6 1.5 0.10 0.9 0.6 0.7 .3ns

Means with different superscripts differ, P<0.05; ns not significant within a column.

Effects of sex, birth rearing, and age of dam on yearling crossbred progeny of Texel x Romney sheep

T. Wuliji1 and K. G. Dodds2

1E (Kika) de la Garza Research Institute for Goats, Langston University, Langston, OK
2AgResearch, Invermay Agricultural Center, Mosgiel, New Zealand

Total of 1259 progeny from groups of Romney, Texel x Romney and Texel x Romney intercross were analyzed. Birth-rearing rank, birth weight (BW), weaning weight (WW), spring weight (SW), greasy fleece weight (GF), oven dry yield (%), fiber diameter, bulk, wool brightness (Y) and yellowness (Y-Z) were measured. Data were analyzed by residual maximum likelihood (REML). Genotype, year, sex, birth rearing rank and age of dam were included as fixed effects, birth day as a covariate and sire as a random effect. Effects of sex, birth rearing and age of dam on progeny performance were shown in Table 1. Males were heavier, and grew more yellow and bulkier wool (P<0.01) than females. Single born and reared animals were heavier (P<0.05) than twin born animals, with twins that were single reared being significantly (P<0.05) heavier at weaning than those that were twin reared. The birth rearing rank did not affect the wool characteristics, except for yield where twin born and reared animals were higher (P<0.05) than the other rearing types. Age of dam had no effect on wool characteristics but 2-year dam had slightly lower birth weight and weaning weight than older dams.

Table 1. Effects of sex, birth rearing and age of dam on production parameters.

Sex1 Birth Rearing Rank Age of Dam
Ewe Ram S.E.D SS TS TT SED 2 3 4+ S.E.D
BW 4.5 4.8 0.04 5.5b 4.2ab 4.2a 0.07 4.3 4.8 4.9 .06ns
WW 23.8 25.2 0.62 27.4c 24.3b 21.8a 0.31 23.5a 25.2b 24.9b 0.30
SW 47.5 54.8 0.37 52.9b 50.5a 50.1a 0.54 50.1a 51.4a 52.0b 0.51
GF 2.54 2.74 0.03 2.67 2.62 2.63 .04ns 2.61 2.67 2.64 .04ns
Yield 64.4 62.4 0.27 63.0a 63.3ab 63.8b 0.38 63.0a 63.8b 63.3a 0.34
Bulk 31.7 32.2 0.20 31.8 32.3 31.8 .29ns 32.1b 31.6a 32.1b 0.26
FD 32.5 32.6 0.18 32.5 32.4 32.7 .70 ns 32.6 32.5 32.5 .24ns
Y 65.3 64.0 0.14 64.7 64.7 64.3 .19ns 64.5 64.6 64.7 .17ns
Y-Z 4.6 5.1 0.08 4.9 4.8 4.9 .10ns 4.8 4.9 4.9 .10ns

1: all traits differ significantly for sexes, P<0.01; Means within rows with a different superscript in the trait columns differ, P<0.05; ns: non significant within rows in the trait columns; SS: single born and reared; TS: twin born and single reared; TT: twin born and reared.

Effects of individual vs group confinement and forage access on performance of artificially reared, confined Alpine kids

A. L. Goetsch*, G. Detweiler, T. Sahlu, L. J. Dawson, and S. Zeng

E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK

Forty Alpine kids (20 females and 20 males) were used to determine effects on performance of individual vs group confinement and access to forage during the suckling period. Kids began the experiment at 3 to 9 d after birth (3.6 ± .10 and 4.0 ± .09 kg initial BW for females and males, respectively). Treatments were: individual confinement in 91 × 91 cm cages (C1); confinement of two kids (one in the experiment and another older) in 182 × 91 cm cages (C2); group confinement (with at least two older kids present) in a 2.43 × 1.22 m pen (P); and P plus free access to alfalfa hay (PF). Milk was consumed ad libitum for 8 wk with free access to a concentrate-based starter diet, followed by a 4-wk post-weaning period, the first 5 d of which entailed restricted milk intake. In the 8-wk suckling period, milk intake was similar among treatments (1.81, 1.80, 1.89, and 1.77 kg/d; SE 34.8), whereas sex influenced the treatment response in ADG (interaction, P = .02) (female: 159, 154, 172, and 154 g/d; male: 175, 193, 162, and 182 g/d for C1, C2, P, and PF, respectively (SE 6.3)). In the 4-wk post-weaning period, ADG was greater (P < .05) for P than for C2 and PF (75, 54, 112, and 49 g/d; SE 16.4), although for the entire 12-wk experiment ADG was similar among treatments (137, 134, 149, and 128 g/d for C1, C2, P, and PF, respectively; SE 6.7). In conclusion, housing two or more Alpine kids together vs alone and offering hay during the suckling period did not enhance performance during or shortly after suckling.

Effect of PEG supplementation of goats grazing shinnery oak pastures in Western Oklahoma

R. C. Merkel1, A. L. Goetsch1, R. Blackwell2, M. Mosely3, S. Hart1, and T. Sahlu1

1E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK 73050
2U.S. Forest Service, USDA/Black Kettle National Grassland, Cheyenne, OK
3Natural Resource Conservation Service, 100 USDA Suite 206, Stillwater, OK

One hundred twenty-nine goats were used in a 112d trial evaluating the use of polyethylene glycol (PEG) to bind dietary tannins found in browse species in western Oklahoma. Three goat breeds were used: 73 Angora (A), 36 males (initial BW 29.6 ± 2.74 kg) and 37 females (initial BW 28.8 ± 2.64 kg); 24 75% Boer × 25% Spanish females (B; initial BW 35.6 ± 3.00 kg); and 32 Spanish males (S; initial BW 34.5 ± 1.41 kg). Animals were divided into four groups of 32, 32, 32 and 33 animals with equal numbers of B, S and A with the exception of one group that had 19 rather than 18 A. All animals received 88 g of a corn-based supplement daily with goats on the PEG treatment receiving an additional 25 g of PEG. Eight shinnery oak paddocks, six to seven acres in size, were used to pasture the goats. Goats rotated between their two assigned pastures every 28 days after weighing. Supplements were not consistently consumed by any group, possibly due to the high forage availability and dustiness of the supplement, and consumption estimated visually averaged between 50 and 65% of that offered. There was no effect of treatment on ADG (control 54 g/d, PEG 62 g/d; SE = 9.92). Angora goats gained less (P < 0.01) than B or S animals (28, 70 and 76 g/d, respectively; SE = 4.1). Results indicate that goats can gain weight grazing shinnery oak pastures at a low stocking rate. Inadequate consumption of PEG may have resulted in a non-significant treatment effect.

Estimating fecal crude protein excretion in goats

A. L. Adams1, J. E. Moore2, A. L. Goetsch1, and T. Sahlu1

1E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK
2Department of Animal Science, University of Florida, Gainesville

As part of an overall goal to estimate protein requirements of goats using the factorial method, equations were developed and tested to estimate fecal CP excretion. Data from 54 trials (n = 189)on CP intake and apparent digestibility in goats were compiled. There were 78 unsupplemented roughages (14 grass hays, 12 legume hays, 4 grain silages, 4 straws, 9 mixed roughage sources, and 35 browse and mixed browse/hay diets) and 111 mixed roughage/concentrate diets in the database. Hypotheses were 1) metabolic fecal CP as a proportion of DMI is constant and 2) true digestibility of CP is constant, and were tested by regressing apparent digestible CP (DCP, % diet DM) on total CP (% DM). Excluding extreme outliers, the equation was: DCP = .899 (CP) - 3.14; n = 179; r2 = .96; intercept = metabolic fecal CP excretion (% DM); and slope = true digestibility of CP. Coefficients from the regression equation were used to compute expected fecal CP (EFCP, g/d): EFCP = .0314 (TDMI) + [1- .899 (CP/100)(TDMI)], where TDMI = total DM intake (g/d). To evaluate the EFCP equation, the main database was divided into subsets for equation development (n = 107) and evaluation (n = 68). Subsets were balanced for TDMI, CP intake, CP digestibility, dietary forage % (FORG), presence or absence of browse in the diet (BRWZ; 1 vs 0, respectively), animal age, breed, and initial BW. Regression of actual fecal CP excretion (AFCP, g/d) on EFCP using the development set yielded the equation: AFCP = 1.160 (EFCP) -2.30; r2 = .89, RMSE = 11.4. The slope of the equation was significantly different from 1 (P < .0001). Multiple regression analysis conducted on the development set, using factors chosen with the stepwise selection option of PROC REG, gave the following equation: predicted fecal CP (PFCP, g/d) = -9.79 + 1.181 (EFCP) + 12.32 (BRWZ) + .0522 (FORG); r2 = .92; RMSE = 9.9. Testing this equation with the evaluation subset showed that the regression of AFCP on PFCP was close to ideal (i.e., intercept = 0, slope = 1, r2 = .93, RMSE = 9.3). In conclusion, when predicting fecal CP excretion by goats, forage concentration and presence or absence of browse in the diet should be considered in addition to dietary CP concentration and TDMI.

Effects of dietary protein level on performance of weaned Boer crossbred and Spanish wethers

I. Prieto1, A. L. Goetsch1, S. Soto-Navarro*,1, V. Banskalieva1, M. Cameron1, R. Puchala1, T. Sahlu1, L. J. Dawson1, and S. W. Coleman2

1E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK
2Grazinglands Research Laboratory, USDA, ARS, El Reno, OK

Boer (3/4) × Spanish (1/4) (BC; n = 23) and Spanish (SP; n = 22) wethers, approximately 4.5 mo of age and 17.6 and 19.4 kg initial BW, respectively (SE = .57), were used to determine effects on growth of protein level in 70% concentrate diets consumed ad libitum for 30 wk. Diets offered were 10.2, 14.2, 18.3, and 23.6% CP (DM basis), and CP concentration in consumed DM was 9.3, 13.8, 17.1, and 22.1% (P1, P2, P3, and P4, respectively), with supplemental protein from soybean meal for P1 and P2 and from soybean meal plus a blend of blood, fish, and feather meals for P3 and P4. Dry matter intake was similar between breeds and among diets (732, 712, 698, and 740 g/d for P1, P2, P3, and P4, respectively; SE 27.0). Average daily gain was greater for P2 (P = .07) and P4 (P < .05) than for P1 (76, 90, 85, and 100 g/d for P1, P2, P3, and P4, respectively; SE = 5.3) and for BC vs SP (97 vs 78 g/d, SE 3.7; P = .05). Similarly, ADG:DMI was lowest (P < .05) among diets for P1 (.106, .126, .121, and .132 for P1, P2, P3, and P4, respectively; SE .0053) and greater (P < .05) for BC than for SP (.135 vs .108; SE .0037). In conclusion, with 70% concentrate, dietary protein levels above 14% DM did not improve performance for either weaned Boer crossbred or Spanish wethers.

Effects of early post-weaning nutritive plane on subsequent growth of goat kids

R.C. Merkel1, A. L. Goetsch1, N. Silanikove2, and T. Sahlu1

1 E (Kika) de la Garza Institute for Goat Research, Langston University, Langston OK
2 Volcani Center, Bet Dagen, Israel

Forty-eight 50% Boer × Spanish doelings (4 mo of age, 20.9 ± 2.35 kg) were randomly assigned to three treatments to test effects of polyethylene glycol (PEG) supplementation of grazed sericea lespedeza and early post-weaning nutritive plane on subsequent growth. Treatments were: barn (B) where goats were kept in individual pens for the 24-wk trial and fed free-choice a 70% concentrate diet (17% CP, 69% TDN); PEG (P); and control (C). In the first 6 wk (Phase 1), P and C doelings grazed .44-ha lespedeza paddocks supplemented with 88 g/d of concentrate with or without an additional 25 g/d PEG. In the subsequent 6 wk (Phase 2) C doelings resided in previously ungrazed 1-ha paddocks dominated by crabgrass, whereas P doelings grazed 1-ha lespedeza paddocks supplemented with approximately 1.5% BW of the B diet. In Phase 3, the final 12 wk, all doelings consumed ad libitum the 70% concentrate diet in confinement. Body weight was determined at 3-wk intervals. ADG were calculated by regression using initial BW as a covariate. Phase 1 ADG ranked (P < .05) B>P>C (157, 97, and 47 g/d; respectively, SE 10.9). ADG in Phase 2 (B 70, P 55, and C 57 g/d; SE 9.3); Phase 3 (B 80, P 85, and C 73 g/d; SE 7.6); and the whole trial (B 87, P 73, and C 56 g/d; SE 8.2) were similar among treatments (P > .05). In conclusion, PEG may have potential to improve weight gain by goat kids grazing tannin-containing sericea lespedeza, although testing over a longer time frame is needed. Differences in ADG in the early portion of the grazing period did not elicit increased ADG later with feeding of a concentrate-based diet relative to continuous concentrate consumption reflecting an absence of compensatory growth.

Effect of ruminally protected betaine on the productivity of Angora goats

T. Shenkoru1, F. N. Owens2, R. Puchala, and T. Sahlu1

1E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK 73050
2Animal Science Department, Oklahoma State University, Stillwater, OK 74078

Twenty-five Angora wethers (20 " 2 kg initial BW and about 7 months of age) were used to evaluate effects of ruminally protected betaine (PB) on BW gain, rumen fermentation products and mohair quality and production. Animals were randomly allocated to five treatments and had ad libitum access to 53 % concentrate diet (15 % CP) for 90 d. Treatments were 2, 4 and 6g /d of PB, 6g /d of unprotected betaine (UPB) and no added betaine (control). In situ ruminal disappearance of protected betaine was 73%., whereas disappearance of UPB at 2 h was complete. Total tract digestibility of BP was 76%. Dry matter intake, feed efficiency and BW gain were similar among treatments. No differences in ruminal VFA, grease fleece weight or quality of mohair were observed among treatments. Molar percentages of acetate, butyrate, isobutyrate and isovalerate were not affected by treatments. However, the molar percentage of propionate showed a significant treatment H time interaction. From the present experiment it is concluded that feeding unprotected and protected betaine up to 6g /d has no effect on performance of Angora goats.

Effect of growth hormone and IGF-I on fiber growth in Angora goats

R. Puchala, S. G. Pierzynowski, T. Wuliji, A. L. Goetsch, I. Prieto, T. Sahlu, and M. Lachica

E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK

The effect of bST and IGF-I on mohair growth in Angora goats was investigated. In experiment 1, sixteen Angora goats (5 mo old; 16 ± 0.5 kg initial BW) were used to evaluate two levels of recombinant bST (0 and 100 g/d). The bST was a slow release zinc-based suspension designed to sustain delivery of bST over a 14-d period. The experiment consisted of a 2-wk pre-treatment period and 8-wk of bST treatment. Goats were given ad libitum access to a mixed diet (15.0% CP; 2.34 Mcal/kg ME; DM basis) and were individually housed in raised, indoor stalls under ambient lighting. Increased plasma IGF-I (P <0.01) was observed in the bST-treated group (1,080 ng/ml compared with the control group (78 ng/ml). Average daily gain increased (P < 0.05) in bST-treated animals (80.9 vs. 63.3 g/d in control group). Mohair production was similar in both groups (0.10 g/100 cm2/d). In experiment 2, six Angora wethers (22 ± 2 kg initial BW) were implanted bilaterally with silicon catheters into the superficial branches of the deep circumflex iliac artery and vein. The area that was supplied by arterial catheter was approximately 300 cm2. For 14 d animals were infused into deep circumflex iliac arteries with either IGF-I (1.7 g/h in 2.4 ml of saline; experimental side) or saline (control side). IGF-I infusion increased the concentration of several essential amino acids in the venous blood of the perfused site, suggesting decreased uptake. The lack of effect of bST on mohair growth is probably due to a lack of anabolic effect on skin tissue of bST/IGF-I with increased nutrient availability to muscle and decreased availability to skin.

Effect of triiodothyronine (T3) administered to a perfused area of skin in Angora goats

R. Puchala, S. G. Pierzynowski, T. Wuliji, A. L. Goetsch, I. Prieto, T. Sahlu, and M. Lachica

E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK

The effect of T3 infusion on mohair growth of Angora goats was investigated using a skin perfusion technique. Six Angora wethers (32 kg) were implanted bilaterally with catheters into the superficial branches of the deep circumflex iliac artery and deep circumflex iliac vein. For the first 14 d of the experiment animals were infused into the deep circumflex iliac arteries with a T3 (one side) and saline (other side, both at 2.4 mL/h). The infusion rate of T3 was 144 g/d, estimated to triple T3 blood concentration in the perfused region. The area of skin supplied by the deep circumflex iliac artery was approximately 300 cm2. An area of 100 cm2 within the perfused region was used to determine mohair growth. Two weeks after the cessation of infusions, perfused areas were shorn. Decreased concentrations of Met, Cys, Lys, Phe, Val, Ileu, Leu, and insulin were observed in the venous blood taken from the deep circumflex iliac vein on the side infused with the T3 compared with blood taken from the saline side (P < .05). Greasy mohair production from the perfused region was increased by T3 infusion compared with the side infused with saline (2.69 vs 2.05 g/100 cm2/28 d, P < .005). Direct skin infusion with T3 resulted in mobilization of amino acids for increased protein synthesis and also affected energy distribution by changing insulin concentration.

South African Boer goat research and production systems

A. L. Goetsch

E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK

A short-term visit to South Africa was conducted to become familiar with goat production, research and extension/outreach programs, with special emphasis on Boer goats. The normal market weight of meat goats is 20 to 30 kilograms, achieved at 1 or 2 months after weaning. Thus, early age growth during suckling is critical and, consequently, stud breeders are selecting for improved mothering ability and milk production. Boers and other goats play an important role in veld or pasture/range management. It is evident that Boers can perform quite well under very extensive, low-input production systems existent in many South African velds. However, Boers are generally less resistant than indigenous goats to some diseases such as 'heart water', transmitted by ticks, and to internal parasites. Variable resistance among Boers to diseases and internal parasites has created interest in selection for such attributes. Similarly, optimal levels of Boer and indigenous goats in crossbreds are being determined to achieve acceptable growth and environmental adaptation. Under US conditions, pertinent questions for use of Boers include susceptibility to internal parasites and nutrient requirements relative to those of other meat goat breeds or types. In conclusion, a better understanding of research and production systems used with Boer goats in South Africa will aid research with Boer goats in the US. This research was supported by the USDA Scientific Cooperation Program, Project No. 58-3148-9-069.

Dipeptides or their amino acids administered to a perfused area of the skin in Angora goats

R. Puchala, S. G. Pierzynowski, T. Wuliji, A. L. Goetsch, I. Prieto, T. Sahlu, and M. Lachica

E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK

Effects of infusion of dipeptides or their amino acids on mohair growth of Angora goats were investigated using a skin perfusion technique. Six Angora wethers (average BW 30 ± 3 kg) were implanted bilaterally with silicon catheters into the superficial branches of the deep circumflex iliac artery and into the deep circumflex iliac vein. For the first 14 d of the experiment, animals were infused into the deep circumflex iliac arteries with a mixture of Met-Leu and Lys-Leu on one side and similar amounts of free amino acids on the other side. The infusion rate of dipeptides were .85 mg Met-Leu and .85 mg Lys-Leu/h in 2.4 ml saline. Infusion rates of amino acids were .474 mg Lys, .483 mg Met and .743 mg Leu/h in 2.4 ml saline. The area of skin supplied by the deep circumflex iliac artery was approximately 300 cm2. An area of 100 cm2 within the perfused region was used to determine mohair growth. Two weeks after the cessation of infusions, perfused areas were shorn. Greasy mohair production from the perfused region was similar for dipeptide infusion compared with free amino acids (5.56 vs 5.69 g/100 cm2 for the 28 d period, respectively, P > .1). However, mohair production was relatively higher than that observed when only saline was infused for 28 d preceding the experiment (4.71 g/100 cm2). No significant changes were observed in concentrations of amino acids, glucose or hormones in blood from the deep circumflex iliac vein (P > .1). In conclusion, the effects of supplementing mohair-producing skin with limiting amino acids given in the free form and as small peptides, had similar effect on mohair growth.

Dairy goat performance with different dietary concentrate levels in late lactation and the dry period

A. L. Goetsch, G. Detweiller, T. Sahlu, R. Puchala, and L. J. Dawson

E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK

Optimal feeding programs for dairy goats in late lactation and in the dry period are not well established. Thus, Alpine does and doelings were used to determine influences of dietary concentrate level in late lactation and the dry period on performance. Concentrate level in late lactation (i.e., 20, 35, 50 and 65%) did not alter milk production by doelings, but milk production by does was lowest for 20% concentrate and greatest for 50%. Body weight in late lactation was affected by concentrate level, but neither body weight nor milk production in the subsequent lactation was altered. Likewise, 65 and 50% concentrate in the dry period with 20 and 35% concentrate in late lactation, respectively, did not influence subsequent lactation body weight or milk production compared with 35 then 50% concentrate in the dry period. With moderate to high quality forage in late lactation and a moderate level of concentrate in the dry period, concentrate levels in late lactation and while dry may not affect subsequent lactation performance regardless of parity. Milk production by doelings in late lactation appears relatively less responsive to dietary concentrate level than that by does.

Factors affecting sale price of performance-tested meat bucks

T. A. Gipson, T. McKinney, and T. Sahlu

E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK

Increased attention in the United States has focused upon meat production in goats and correspondingly, upon methods to select genetically superior breeding stock. Langston University in collaboration with the Oklahoma Meat Goat Association has established a performance test for meat bucks to measure growth and feed efficiency. In 1999, forty-seven bucks were enrolled in the performance test. Following the performance test, an auction sale was held and 30 of the performance-tested bucks were sold. The objective of this study was to determine performance test factors that affect sale price. Performance test traits included average daily gain (g/d), feed efficiency (g gain/g feed intake), final weight (kg), total gain (g), loin-eye area (cm2), rear leg circumference (cm), breed type (Boer or BoerX), breeder and an index score calculated using average daily gain, feed efficiency, loin-eye area, and rear leg circumference. None of the performance test traits affected (P>.10) the breeders' decision either to sell the buck or to keep it for themselves. Breed type was the only performance test trait to affect significantly (P<.01) the sale price with purebred Boer bucks selling for twice that of crossbred bucks, $233 vs. $116, respectively. Buyers of performance-tested bucks appear to rely upon factors other than those measured in the performance test. They perhaps rely upon visual factors such as conformation or color patterns or upon other factors such as pedigree.

Enhancing goat production and extension in Ethiopia

R. C. Merkel1, T. Sahlu1, G. Abebe2, G. Animut3, A. L. Goetsch1, and T. A. Gipson1

1E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK
2Awassa College of Agriculture, Awassa, Ethiopia
3Alemaya University of Agriculture, Dire Dawa, Ethiopia

Langston University is collaborating with Awassa College of Agriculture (ACA) and Alemaya University of Agriculture (AUA) in Ethiopia to improve the goat extension activities of theinstitutions as well as regional goat production. This will be done through targeting women livestock producers. Women and children in Ethiopia are largely responsible for the care of goats and for the harvesting and sale of products, such as milk and fiber. Women are also the decision makers in what their family consumes and how a major portion of the household budget is spent. Putting goats in the hands of women will provide them with products (milk and meat) that could be used for household consumption or for sale. Cash income realized from such sales can then be used for purchased foodstuffs, educational or health-related expenses or other household needs. Goat "packets", consisting of four to six does and one buck, will be given to women cooperators with the stipulation that they return to the project several young does that will enter a pool for distribution to new cooperators. A training program tailored to present the basics of goat production, feeding and management will be presented to the women. Tree legume seeds and forages will be made available for the women to plant. ACA and AUA personnel will monitor the progress of the cooperators as well as offering assistance and further training. Activities completed are: selection of cooperators, initiation of training programs, preparation of seeds, forages and animals for distribution.

Sericia lespedeza for grazing goats

S. P. Hart, T. A. Gipson, and T. Sahlu

E (Kika) de la Garza Institute for Goat Research, Langston University, Langston, OK

Spanish stocker goats were grazed on a pasture of sericea lespedeza (Lespedeza cuneata) to determine animal performance and the effects of sex and initial weight on performance. Eighty female and eighty wether Spanish kids weighing from 15 to 30 kg were used. Goats grazed from May 20 to September 27 on a 16 ha pasture of sericea lespedeza. Goats were dewormed, eartagged, vaccinated (enterotoxemia and tetanus) and weighed before turning into the pasture. Goats gained 10 kg for the 130-day grazing period. Weight gains were lower (P<.10; 1.2 kg vs 3.0 kg) for the second month of the study as compared with the other months. The amount of weight gained was not affected by sex or initial body weight (P>.05). Fecal egg counts increased linearly (p>.05) over the grazing study but averaged only 300 eggs per gram at the end of the study. Spanish kids gained well on sericea lespedeza and could graze the whole summer without being dewormed. Neither sex nor initial weight were important factors in determining animal performance on sericea lespeceza. Sericea lespedeza, since it is a low-input crop, has potential to provide economical gains for goats.

SUMMARIES OF RECENT JOURNAL ARTICLES

Adrenocortical response to ACTH in Angora and Spanish goat wethers

C. A. Toerien, R. Puchala, J. P. McCann, T. Sahlu, and A. L. Goetsch

Journal of Animal Science 77:1558-1564. 1999.

Angora goats, on a body weight basis, are the highest fleece-producing ruminant, but are susceptible to stress. rrespective of sex, Angora goats exhibit an apparent impaired capacity for gluconeogenesis and a consequent inability to raise blood glucose levels under cold and(or) nutritional stresses. This may contribute to abortions and adult fatalities. It has been hypothesized that the decreased gluconeogenic ability of Angora goats is simply due to nutrient partitioning to fiber production at the expense of labile body protein reserves and glucogenic precursors. However, subclinical hypoadrenocorticism could exist in Angora goats as well. Likewise, it has been postulated that genetic selection for mohair production has been accompanied by coselection for hypoadrenocorticism, since cortisol inhibits fiber follicle activity. In primary hypoadrenocorticism, low cortisol production and blood levels result from low adrenal cortisol release in response to adrenocorticotropin hormone (ACTH) stimulation, because of factors such as low adrenal mass and atrophy or destruction of the adrenal cortices; secondary hypoadrenocorticism is the product of low pituitary ACTH production. Integrity of the adrenal cortex of Angora goats has not been directly studied. Thus, in this study the hypothesis that Angora goats exhibit subclinical primary hypoadrenocorticism was tested by measuring plasma cortisol response in stress-tolerant Spanish and stress-intolerant Angora goats under conditions of simulated acute and chronic ACTH challenges. Based on results of this experiment, the adrenal cortex in Angora goat wethers appears fully capable of mounting an appropriate cortisol response to adrenocorticotropic hormone stimulation. Thus, the ability of Angora goats to cope with stress may involve factors other than the capacity of the adrenal cortex to produce cortisol. However, possible changes in hypothalamic-pituitary-adrenal cortex axis function due to pregnancy and(or) dysfunction in cell-signaling mechanisms for cortisol action may play a role in the well established stress intolerance of Angora goats.

Dietary protein effects on and the relationship between milk production and mohair growth in Angora does

T. Sahlu, H. Carneiro, H. M. El Shaer, J. M. Fernandez, S. P. Hart, and A. L. Goetsch

Small Ruminant Research 33:25-36. 1999.

Recently farmers in the central and midwestern U.S. have shown interest in using traditional crops and land for production of mohair from Angora goats as a means of diversification. Angora goats are valued primarily for mohair production, but income also arises from the sale of kids. Thus, there is need for both high milk production to promote maximal kid live weight gain and an ample supply of nutrients to skin for rapid mohair growth. However, wool growth is markedly decreased in lactation because of nutrient partitioning to the mammary gland for milk synthesis. Angora goats are the highest fleece-producing ruminant on a body weight basis; therefore, there also may be a negative relationship between milk production and fiber growth in Angora goats, although one has yet to be reported or characterized. Relatively low milk production by Angora goats and a short lactation period indicate that lactation could impact mohair growth differently than that of sheep wool. Furthermore, to avert or minimize a potential decrease in mohair growth as a result of a priority for nutrient use by the mammary gland, and because requirements for amino acids, particularly those containing sulfur, are high in Angora goats, an increased level of dietary crude protein may be beneficial. In this regard, increasing dietary crude protein level has increased mohair production by nonlactating Angora goats, as has skin perfusion of amino acids. Hence, the primary objectives of this study were to measure the relationship between, and dietary crude protein level effects on, milk production and mohair growth by Angora does in different periods of lactation. Based on results of this experiment, milk production by Angora does in wk 3 through 16 of lactation increased linearly with increasing crude protein level in a diet with a high concentrate level. Crude protein intake was correlated with milk production but not with live weight gain or mohair growth. Milk production and mohair growth were negatively related in mid-lactation but not in early or late stages, but dietary crude protein level did not alter the relationship between milk production and mohair growth. Under our conditions, varying the dietary crude protein level did not overcome effects of partitioning of nutrients to milk synthesis in lactating Angora does or increase mohair growth by increasing skin nutrient supply.

Effects of bovine somatotropin and ruminally undegraded protein on feed intake, live weight gain, and mohair production by yearling Angora wethers

J. J. Davis, T. Sahlu, R. Puchala, M. J. Herselman, S. P. Hart, E. N. Escobar, S. W. Coleman, J. P. McCann, and A. L. Goetsch

Journal of Animal Science 77:1029-1036. 1999.

Effects of growth hormone on wool growth are variable. Exogenous ovine growth hormone generally depresses wool growth during the period of administration, although bovine somatotropin (bST) has increased wool growth by sheep during and after treatment. A biphasic response in wool growth to bST treatment has been reported, with a decrease during treatment but an increase thereafter; the decrease during treatment was largely a result of reduced fiber diameter. Effects of bST on mohair production by Angora goats have not been extensively studied. Source of dietary protein can impact magnitudes of response in animal performance to bST. For example, bST effects on average daily gain, feed efficiency, and hind limb muscle mass were greater for diets formulated with fish meal, to elevate ruminally undegraded protein, compared with diets containing soybean meal. Comparable interactions in milk production by lactating dairy cows have been observed as well. Interactions in fiber growth by Angora goats may differ from those for lactating dairy cows or growing sheep or cattle. Effects of growth hormone on nutrient partitioning are not skin- or fiber-specific; nutrient requirements for fiber growth differ from those for milk synthesis and accretion of peripheral muscle; and body composition, which impacts potential nutrient partitioning properties of bST, varies among animal types. Therefore, the objectives of this study were to investigate effects and interactions of bST treatment and dietary level of ruminally undegraded protein on feed intake, average daily gain, and mohair production by yearling Angora wethers. Based on results of this experiment, dietary addition of ruminally undegraded protein can increase mohair production by yearling Angora goats with and without somatotropin treatment. Treatment with somatotropin does not appear promising as a means to increase mohair production by yearling Angora goats regardless of dietary concentration of ruminally undegraded protein. However, somatotropin can influence change in feed intake by Angora goats elicited by dietary inclusion of ruminally undegraded protein, thereby impacting the ratio of fleece production to feed intake.

Effects of zinc-methionine on performance of Angora goats

R. Puchala, T. Sahlu, and J. J. Davis

Small Ruminant Research 33:1-8. 1999.

The essential amino acids lysine, methionine (Met), and cyst(e)ine stimulate wool and mohair growth. Omission of Met reduces wool growth and decreases both length growth rate and diameter. Skin and fiber (wool, mohair) impose heavy demands on the utilization of circulating sulfur amino acids. It has been predicted that 80% of the total free blood pool of combined cysteine and Met would be used for fiber growth. Being responsible for the initiation of protein synthesis, Met is important in fiber growth. Met can be converted to cystine mainly in the liver, but also to some extent in other tissues. Supplementation with specific amino acids has influenced mohair growth in Angora goats. It may be cost effective to increase absorption of most limiting amino acids such as Met through dietary supplementation of specific amino acids, rather than increasing absorption of a large number of amino acids through increasing of the total dietary CP level. Apart from the major nutrients such as protein, many vitamins and trace elements are essential for fiber growth. Zinc (Zn) functions directly in the process of wool growth; thus, Zn deficiencies can seriously affect wool growth. Zinc is needed for the functions of over 100 enzymes, and essential for DNA, RNA, protein synthesis and, as such, cell division. It has been suggested that primary impact of Zn deficiencies on wool growth is through impaired protein synthesis. Commercially available Zn-Met complexes provide both Zn and Met. If Zn-Met is absorbed and transported without modification, the complex may provide a means of increasing tissue supply of Met, which should increase animal productivity when Met is limiting. Therefore, objectives of this study were to investigate effects of dietary supplementation with Zn-Met (Zinpro 40, Edina, MN) or zinc oxide on mohair growth, BW gain, and concentrations of blood metabolites in Angora goats. Dietary inclusion of supplemental Zn-Met, regardless of level increased live weight gain in yearling Angora goats, but only numerically increased mohair production with a basal diet adequate in Zn. Live weight gain was greater for goats supplemented with the same quantity of Zn in the form of Zn-Met vs ZnO, even though plasma Zn concentration was similar. In conclusion, with an 11% crude protein, Zn-adequate diet, 1 g Zn-Met may offer little or no potential to improve fiber production by Angora goats.

Effects of mimosine and 2,3-dihydroxypyridine on fiber shedding in Angora goats

P. J. Reis, R. Puchala, T. Sahlu, and A. L. Goetsch

Journal of Animal Science 77:1224-1229. 1999.

Leucaena (Leucaena leucocephala) is widely used as a forage for livestock in tropical and subtropical regions. However, seeds and leaves are high in mimosine, a toxic, nonprotein amino acid-like compound, which causes alopecia in various species and fiber shedding in sheep. Mimosine has been extensively studied in Merino sheep as a potential chemical defleecing agent. Though mimosine is rapidly removed from the body, intravenous infusion for 2 d at 80 to 100 mg/(kg body weight · d) has consistently caused fiber shedding 7 to 10 d after treatment commenced. This level of infusion yielded a plasma mimosine concentration of approximately 100 mol/L. Sheep can also be defleeced by single oral doses of 400 to 600 mg/kg body weight of mimosine, raising plasma mimosine concentration to greater than 100 mol/L 24 h after dosing. In the rumen, mimosine is converted to 3-hydroxy-4(1H)-pyridone (DHP), which is not depilatory in sheep. Some 3,4-DHP may be further converted to 2,3-DHP, and depilatory properties of 2,3-DHP have not been examined. Mimosine, or other defleecing agents such as epidermal growth factor, may be useful for removing fiber of Angora goats as well as of sheep. In this regard, in an experiment at the E (Kika) de la Garza Institute for Goat Research, five Angora goats were intravenously infused with mimosine for 2 d at 75 mg/(kg body weight · d), which is slightly less than the level commonly used for sheep. Fiber growth was unaffected in two goats, but there was partial or complete alopecia within 10 d in the other three goats. In another Institute study, mohair fiber growth was not affected and defleecing was not induced by 3-d perfusion of a local area of skin of Angora goats with mimosine at 20% of a whole animal defleecing dose for sheep. Objectives of the present study were to determine efficacy for removing fiber of Angora goats by 2-d intravenous infusion of different levels of mimosine or one level of 2,3-DHP. Effects of two levels of an oral dose of mimosine were also investigated. Based on results of this experiment, mimosine is a depilatory agent for Angora goats. Two-day infusion of Angora goats with levels of mimosine similar to those effective for defleecing in sheep were effective in removing Angora fiber. However, mimosine may not remove all Angora fibers, particularly primary fibers, when in a temporary resting phase. Oral mimosine administration at doses effective to defleece sheep may be less efficacious with Angora goats. Further research is required to fully characterize seasonality of follicle activity for Angora goats in the United States to most effectively use compounds such as mimosine to defleece, and to develop practical means of mimosine delivery, such as feeding of Leucaena leucocephala.

Effects of mimosine on plasma amino acid concentrations in Angora goats

P. J. Reis, R. Puchala, T. Sahlu, S. P. Hart, and A. L. Goetsch

Small Ruminant Research 33:55-61. 1999.

The naturally-occurring amino acid mimosine causes alopecia in Merino sheep and Angora goats. Mimosine appears to act as an antimitotic agent, but various other possible biochemical effects have been noted as well. Mimosine is degraded in the rumen to 3,4-dihydroxypyridine (3,4-DHP), some of which may be further converted to 2,3-dihydroxypyridine (2,3-DHP). Neither compound causes alopecia in sheep or goats, although 3,4-DHP inhibits cell division in wool follicle bulb cells in vitro. Mimosine may interfere with some aspects of amino acid metabolism. For example, it has been suggested that mimosine acts as a tyrosine analogue and reported that mimosine inhibits activity of some enzymes involved in tyrosine metabolism. It has also been observed that mimosine included in the diet of rats reduced serum tyrosine concentration. Mimosine inhibits activity of pyridoxal-requiring enzymes and, thus, could decrease methionine conversion to cysteine via the transulfuration pathway. In accordance, in recent studies with Angora and Alpine goats both mimosine and 2,3-DHP influenced plasma amino acid concentrations. Parenteral administration of mimosine or a perfusion of an area of skin reduced concentrations of some amino acids in plasma, but effects were variable. However, blood levels of mimosine in these studies were less than required to defleece sheep (i.e., 100 mol/L) and did not induce fiber shedding. The administration of 2,3-DHP increased plasma concentration of some amino acids). Mimosine holds promise as a means of inducing shedding. In order to eventually employ mimosine as a chemical defleecing agent, research is needed, such as to develop practical means of delivery and to thoroughly understand all other physiological changes elicited. Consequently, objectives of this experiment were to examine influences of 2-day infusion of mimosine, adequate to defleece, and of oral dosing of mimosine on plasma concentrations of amino acids in Angora goats. Based on results of this experiment, physiological effects of mimosine when infused in Angora goats for 2 days at levels that defleece include altered plasma concentrations of some amino acids. However, based on oral doses of mimosine, such effects appear relatively short-term or -lived. In general, responses to mimosine infusion and dosing seem threshold in nature, involving both mimosine plasma concentration and length of time that plasma mimosine concentration is above thresholds. The pattern of change in plasma mimosine concentration due to oral dosing varied considerably among amino acids, implying alteration of various physiological processes or perhaps different threshold mimosine levels or periods of time of elevated plasma mimosine necessary for effects. In order to eventually use mimosine as a practical means of defleecing, further research is necessary to determine production impacts of mimosine on plasma amino acid levels and, if necessary, modes of preventing consequent adverse effects, such as supplementation.

Energy expenditure of Angora bucks in peak breeding season using the doubly labeled water technique

C. A. Toerien, T. Sahlu, and W. W. Wong

Journal of Animal Science 77:3096-3105. 1999.

In order to profitably raise livestock, a thorough knowledge of nutritional requirements is necessary, as well as is a good understanding of the nutrients delivered to the animal by consumption of different feedstuffs. There is little information on energy requirements of buck goats during the breeding season. In part this relates to the difficulty and expense in using the few available, appropriate experimental procedures, which must be applied with unrestricted movement and allow expression of individual behavior patterns. Thus, a method known as the doubly-labeled water technique was used to measure energy expenditure of Angora bucks in single-buck breeding groups and peak breeding season. Surprisingly, total energy expenditure during peak breeding season, corrected for energy used in mohair growth, was only 9% greater than the maintenance energy requirement. There was only a weak relationship noted between the number of does marked and energy use attributable to activity, suggesting importance of individuality in style and persistence while courting and a perhaps less than expected influence of the number of does. In conclusion, breeding activities in single-buck breeding groups did not markedly increase energy requirements of Angora bucks.

Effects of level of feed intake on body weight, body components, and mohair growth in Angora goats during realimentation

T. Sahlu, S. P. Hart, and A. L. Goetsch

Small Ruminant Research 33:251-259. 1999.

Angora goats are the highest fleece-producing ruminant on a body weight basis. As with wool-producing sheep, poor nutrition affects mohair production by Angora goats, as well as affecting gain or maintenance of body weight. Pastures for Angora goats vary widely with season and rainfall in quality and available forage mass, often resulting in seasonal reductions in mohair growth, body weight, and body condition. Mohair production and body weight can be increased during periods of poor grazing conditions by supplementation, though with associated monetary and labor inputs. Hence, a better understanding of effects of nutrition on mohair production could lessen production costs or increase productivity of Angora goats. On a long-term basis, changes in mohair production and body weight elicited by nutritional plane and supplementation are positively related. However, physiological processes controlling body weight gain and mohair growth differ. Thus, short-term periods of nutrient restriction may have dissimilar magnitudes and durations of effects on body weight and mohair growth. Hence, objectives of this experiment were to evaluate mohair growth and BW change during and after different levels of feed intake restriction. Based on results of this experiment, different levels of restricted feeding of a 14.7% crude protein, 70% concentrate diet for 40 days decreased mohair growth in the last 20 days of the restriction phase and also in the last 21 days of the subsequent 41-day realimentation phase, even though body weight change in the latter part of realimentation increased with increasing severity of previous feed intake restriction. In conclusion, feed intake restriction can have longer term effects on fiber growth than body weight change, suggesting that special attention being given to avoiding even short-term periods of low feed intake if maximal fiber production is to be achieved.

Heat energy for growing goats and sheep grazing different pastures in the summer

M. J. Herselman, S. P. Hart, T. Sahlu, S. W. Coleman, and A. L. Goetsch

Journal of Animal Science 77:1258-1265. 1999.

Energy used by ruminants to graze is thought affected by environmental conditions, such as land area and topography and types of herbage available. Currently, the National Research Council (NRC) 1981 publication on the nutrient requirements of goats recommends that activity energy costs be estimated as 25% of the maintenance cost for light activity, 50% with semiarid rangeland and slightly hilly conditions, and 75% with sparsely vegetated rangeland or mountainous transhumace pasture. However, differences among forage systems typical of goat production conditions in the US or among ruminant species or breeds of a particular species are largely unknown. Thus, this experiment was conducted to investigate influences of animal type (Angora goat, Spanish goat, and Suffolk × Rambouillet sheep wethers) on energy used for activity during summer grazing of two types of grass-based pastures. An improved pasture treatment consisted of 0.7-hectare pastures primarily of Old World bluestem and johnsongrass, and a native pasture treatment entailed 10.8-ha paddocks dominated by big and little bluestems and indiangrass. The NRC (1981) publication suggests that activity energy costs may be greater for goats than for other ruminants such as sheep. However, in this experiment total energy expenditure was greater for sheep, which related to a longer period of time spent grazing and greater energy intake, with the endresult of a similar quantity of stored energy by the sheep and goats. Energy intake was similar between native and improved pastures, although grazing time and the activity energy cost were greater for native pastures. Animals on native pasture also took more steps per unit of time spent grazing, implying that increases in energy intake for native pasture that could be achieved through increased grazing time would occur at a relatively greater energy cost than for improved pasture. Consequently, forage availability may be relatively more important for achieving energy intake adequate for body weight maintenance or greater with pasture conditions similar to those of the native pasture treatment than with the improved pasture treatment. Furthermore, grazing conditions of improved and native pasture treatments may similarly influence productivity by goats and sheep and by different goat breeds.

Growth of Spanish, Boer × Angora and Boer × Spanish goat kids fed milk replacer

J. Luo, T. Sahlu, M. Cameron, and A. L. Goetsch

Small Ruminant Research. In Press. 2000.

Contributions of heterosis for economically important traits have been well documented in other species. The Boer goat has long been recognized for its superior meat producing ability and is widely used to improve growth and carcass traits of local breeds through crossbreeding. It has been noted that Boer crossbred kids were 15 to 20% heavier at weaning than purebred kids of the dam breed. Greater BW and BW gain for Boer crosses than for Spanish goats also has been reported, although feed efficiency was similar. Under an extensive management system, Boer crosses (Alpine, Spanish and Tennessee stiff-legged goats used as maternal breeds) were heavier at 4, 8 and 12 wk of age compared with purebred Boer goats, although the advantage diminished postweaning with advancing age. However, a computer simulation suggested that Boer goats may not excel in growth and reproduction under extensive management conditions, implying genotype × environment interactions. Though performance of Boer goats under extensive management systems has not yet been well characterized, benefits in offspring performance with Boer use as a terminal sire breed under intensive management conditions are generally accepted. Acidified milk replacer has been widely used in rearing young calves and kids, with advantages of reducing milk feeding and labor costs and simplifying management. Kids fed cow milk replacer can grow as rapidly as kids given goat or cow milk. Milking ability of the dam can greatly influence the opportunity of kids to express growth potential; therefore, hand-rearing eliminates such maternal effects. However, information is lacking on how performance of Boer crosses compares with Spanish goat kid performance during the preweaning period under identical feeding and management conditions, such as with feeding of milk replacer. Therefore, the objective of this study was to compare preweaning performance of two Boer crossbreds and Spanish goats under standardized nutritional conditions - feeding acidified milk replacer in an intensive management system. In summary, Boer × Angora kids consumed more milk replacer from birth to 3 wk of age than did BS and S kids, although intake was similar among genotypes in wk 3 to 8. Starter diet intake was greatest among genotypes for BS, and the feed conversion ratio was 13% greater for Boer cross kids than for S kids. This study reflects that Boer crosses exhibit superior growth and feed efficiency during the preweaning period compared with Spanish kids under intensive management conditions.

Defleecing of Angora and Spanish goats using Leucaena

A. J. Litherland, A. Yami, T. Sahlu, and A. L. Goetsch

Journal of Animal and Feed Sciences 8:525-532. 2000.

Leucaena leucocephala is a tropic tree legume with a high nutritive value (e.g., 14 to 30% crude protein), which is often used in ruminant diets in drought-prone areas of developing countries. However, Leucaena contains mimosine, a free amino acid that can be toxic to unadapted ruminants. In wool follicle bulbs, mimosine inhibits DNA synthesis and, hence, cell division. Following mimosine treatment, dividing fiber-producing follicles of sheep and goats have shed their fibers. Similarly, it is conceivable that mimosine could be used with goats to remove cashmere from active secondary follicles without loss of guard hair in seasonally inactive primary follicles, and perhaps true mohair could be separated from undesirable kemp fibers in the Angora goat as well. However, economical means of mimosine delivery have not yet been established. Leucaena feeding may hold promise in this regard. Therefore, objectives of this experiment were to determine effects of the dietary inclusion of a moderate level of Leucaena on fleece shedding and subsequent fiber characteristics of Angora and Spanish goats. Thirty Angora (16 kg) and 20 Spanish (19 kg) 8-month-old doelings, having not previously consumed Leucaena, were used. A diet of 22.5% Leucaena leaf meal (0.17% mimosine in total diet dry matter) was consumed ad libitum for 8 days starting on November 13, with daily mimosine intake in the first 3 days averaging 56 mg/kg body weight. Results of this experiment indicate potential for use of fed Leucaena as a source of mimosine to induce fleece shedding in goats similar to that for sheep, apparently without marked subsequent effects on productivity. Future research should entail higher dietary levels of mimosine, through greater inclusion of Leucaena or use of Leucaena higher in mimosine. In addition, results of this experiment suggest that further experimentation with Leucaena and mimosine to defleece should consider both mohair- and cashmere-producing goats, because of possible differences in responsiveness to mimosine in shedding and carryover effects.

Fatty acid composition of goat muscles and fat depots

V. Banskalieva, T. Sahlu, and A. L. Goetsch

Small Ruminant Research. In Press. 2000.

There have been relatively few studies on the fatty acid composition of lipids in muscles and fat depots of goats. The present reports available are difficult to use for comparisons, in that samples were collected from muscles and fat depots at various anatomical locations and experiments entailed different designs, and procedures and methodologies differ among experiments as well. Interactions among diet, age, live weight, breed and rearing conditions in the fatty acid composition of lipids in different types of muscles and fat depots in goats have not been extensively studied, and little attention has been given to the characteristic of goats to deposit high levels of internal fat. The goat is known to produce relatively lean meat, yet there have been only a few incomplete reports on the mono- and polyunsaturated fatty acid concentration in muscle (being of importance for human health). For example, currently conjugated linoleic acid, as an anticarcinogenic factor, is the subject of a large number of investigations with ruminants, but not yet with goats. Thus, goat meat fatty acid composition deserves more research attention, especially now when different systems of nutrition and breeding are being tested for improving goat meat production.

Effect of restricted consumption of water and(or) dry matter in milk replacer on growth by male and female Alpine kids

A. L. Goetsch, R. Puchala, M. Lachica, T. Sahlu, and L. J. Dawson

Journal of Animal and Feed Sciences. In Press. 2000.

A concern of many goat producers is feeding management in the first few months of life for kids removed from does soon after birth. Dairy goats are typically not allowed to nurse kids to prevent transfer of potential diseases, in addition to useof milk for human consumption. Also, suboptimal mothering ability of and(or) milk production by high fiber- and meat-producing goats can result in orphan kids, often twins and triplets. Current management systems do not facilitate rapid transition at weaning from milk replacer or milk to dry feed. In some instances, milk replacer is offered at relatively high levels (e.g., free-choice) for much of the pre-weaning period, which may retard kid interest in and consumption of dry feeds. This could result from the physical filling effect of milk, primarily relating to milk volume, and also to energy and nutrients being supplied. Hence, development of management systems for milk replacer that promote a quick transition to dry feeds are of considerable interest. Furthermore, because of differences in growth potential, such feeding practices might differ between female and male kids. Objectives of this experiment were to determine effects of restricted consumption of water and(or) dry matter in milk replacer on growth of male and female Alpine kids. Seventy-nine Alpine kids (35 female and 44 male) were used in the experiment, beginning at 3 to 9 days after birth with a commercial milk replacer fed twice daily. Treatments entailed consumed free-choice consumption (AS/AV), restricted consumption of water (AS/RV), or restricted consumption of both water and dry matter (RS/RV). Live weight gain was lowest among treatments for RS/RV in weeks 1 to 4 (146, 131, and 118 g/day) and 5 to 8 (137, 140, and 115 g/day for AS/AV, AS/RV, and RS/RV, respectively). However, sex influenced treatment effects on live weight gain in weeks 1 to 8 (female: 129, 120, and 117 g/day, and male: 155, 151, and 116 g/day for AS/AV, AS/RV, and RS/RV, respectively). Milk replacer treatment did not affect live weight gain in the subsequent 4-week period after weaning. In summary, restricting intake of water alone in milk replacer did not enhance live weight gain of Alpine kids, and lower growth potential of female vs male kids may lessen susceptibility to effects of limited milk replacer dry matter intake.

Effects of dietary sulfur level on amino acid concentrations in ruminal bacteria from ruminal fluid of goats

H. Carneiro, R. Puchala, F. N. Owens, T. Sahlu, K. Qi, and A. L. Goetsch

Small Ruminant Research. In Press. 2000.

Mohair production by Angora goats can be affected by plane of nutrition, including dietary S concentration. The high concentration of cysteine in keratain relative to that in plant material suggests that wool- and mohair-producing ruminants could require greater quantities of S-containing amino acids than other ruminant classes. Most protein and S-containing amino acids available for digestion and absorption by ruminants are derived from dietary protein escaping ruminal fermentation and microbial protein synthesized in the rumen. Microbial protein formed in the rumen depends on the quantity of OM fermented and availability of required nutrients such as ammonia. Besides effects on the quantity of microbial protein synthesized, nutrient availability can impact composition of microbial cells, and it has been proposed that the level of amino acids containing S (methionine, cystine and cysteine) in ruminal microbes might be reduced by a deficiency of S. Therefore, the objective of this experiment was to determine the effect of dietary S on amino acid concentrations in ruminal fluid bacterial cells of goats. 12 Angora (18 ± 0.6 kg BW) and 20 Alpine (24 ± 1.0 kg BW) goat wethers consumed diets (14.3% CP and 1.67-1.80 Mcal/kg ME, DM basis) with 0.11, 0.20, 0.28 or 0.38% S (supplemental S: CaSO4; N:S ratio: 21, 12, 8 and 6, respectively) for 10 weeks to determine effects of dietary S on amino acid concentrations in ruminal fluid bacteria. In this experiment, dietary S as influenced by level of an inorganic source did not appreciably alter amino acid concentrations in bacteria from ruminal fluid of goats harvested immediately before and at 4 h after feeding a diet moderate to low in digestibility. Thus, there was no evidence to suggest effect of dietary S on S-containing amino acids available for animal metabolism, apart from possible impact on the quantity of synthesized microbial protein.

Growth and cashmere production by Spanish goats consuming ad libitum diets differing in protein and energy levels

D. S. Ivey, F. N. Owens, T. Sahlu, T. H. Teh, P. L. Claypool, and A. L. Goetsch

Small Ruminant Research 35:133-139. 2000.

Interactions between dietary protein and energy levels with ad libitum feed intake in effects on cashmere fiber growth have not yet been extensively investigated. Thus, the objective of this experiment was to evaluate the effects and interactions of ad libitum consumption of diets differing in crude protein and metabolizable energy concentrations on growth and cashmere fiber production by young/growing US Spanish wether goats. Thirty-six Spanish goat wethers (averaging 196 days of age and 17.5 kg body weight at experiment initiation) from a herd previously selected for cashmere growth were used to determine effects and interactions of ad libitum consumption of diets differing in concentration of crude protein (10 and 15%) and metabolizable energy (2.00, 2.35, and 2.70 Mcal/kg; dry matter basis) on growth and cashmere fiber production in an 84-day fall-season experiment. With growing Spanish wethers in the fall season and ad libitum consumption of diets approximately 40, 60, and 80% concentrate, corresponding to 2.00, 2.35, and 2.70 Mcal/kg of metabolizable energy, respectively, cashmere fiber diameter was greater for 15 versus 10% dietary crude protein regardless of metabolizable energy level. Diet composition did not impact cashmere fiber length. Dietary concentrations of crude protein and metabolizable energy did not alter guard hair weight but interacted in weight of cashmere fiber. However, similar numerical differences, although of lesser magnitude, among treatments in pre-experiment cashmere fiber weight existed, suggesting need for further experimentation with greater animal numbers and(or) treatment allotment based on animal differences in most important variables.

Influences of the number of fetuses and levels of CP and ME in gestation and lactation supplements on performance of Spanish does and kids during suckling and post-weaning

D. S. Ivey, F. N. Owens, T. Sahlu, T. H. Th, L. J. Dawson, G. A. Campbell, and A. L. Goetsch

Small Ruminant Research 35:123-132. 2000.

Pregnancy and lactation appear to influence mohair growth via competition for nutrients between skin follicles and other tissues. Conversely, based on research with Australian feral goats, effects on pregnancy and lactation on cashmere fiber growth are due to physiological changes associated with pregnancy and lactation rather than via nutrient competition, which impact times of cashmere cessation and initiation in the growth cycle. Effects of the nutritional plane of does in the last one-third of gestation and of kids during suckling also have not been extensively studied. Objectives of this research were to determine effects of supplement levels of metabolizable energy and crude protein for US Spanish does, from a herd selected for cashmere fiber production, in gestation and lactation on performance of does and kids during suckling and post-weaning. Forty-eight mature US SPanish does (40 kg) were used in the experiment. At 60 days of gestation, does with single or twin fetuses consumed mature bermudagrass hay ad libitum and 1% body weight (dry matter basis) of supplements with 18.6 or 28.5% crude protein) and 2.2 or 2.8 Mcal/kg metabolizable energy. The high energy-high protein supplement was offered at 1.5% body weight (dry matter basis) for 15 days after birth, and does received the same supplement treatments as in gestation thereafter until weaning at 50 days after parturition. For a 50-day post-weaning period, kids consumed ad libitum the high energy-low protein supplement. With a moderate plane of nutrition during gestation elicited by ad libitum consumption of low-quality grass hay and a relatively high level of supplemental concentrate, the number of fetuses did not affect cashmere weight of US Spanish does from a herd selected for cashmere fiber production, with shearing in February at 100 days of gestation. Different supplement metabolizable energy and crude protein levels during gestation and lactation periods did not influence birth weight of single or twin kids. Kid body weight and cashmere weight after 50-day suckling and post-weaning periods were affected by an interaction between the number of fetuses and level of metabolizable energy in supplements given to does in gestation and lactation, suggesting possible impact of nutrient demand as influenced by number of fetuses on doe responses to different supplements in milk production and consequent kid body weight. However, because of the limited number of observations in this experiment, these findings warrant further research.

Effects of dietary protein source on fleece and live weight gain in Angora doelings

A. J. Litherland, T. Sahlu, C. A. Toerien, R. Puchala, K. Tesfai, and A. L. Goetsch

Small Ruminant Research 35:133-139. 2000.

The US Angora goat, on a BW basis, is one of the highest fleece-producing ruminants. Mohair growth requires litle energy but much protein is needed. In particular, requirements for the sulfur-containing amino acids cysteine and methionine are high. However, the array of amino acids needed for fleece-free BW gain is different from that needed for fiber growth. Thus, diets containing supplemental protein sources promoting high BW gain may not necessarily do so for fiber growth, which would be of special importance for growing, fiber-producing ruminants, such as yearling Angora doelings typically bred for kidding at 2 years of age. Therefore, objectives of this study were to determine if different common supplemental dietary protein sources have similar effects on live weight and mohair growth in yearling Angora doelings. Fifty-one yearling Angora doelings (20 ± 0.6 kg initial BW) were used; diets consisted of approximately 40% roughage and 18 to 19% CP (DM basis), of which two-thirds was supplied by corn gluten meal, cottonseed meal, hydrolyzed feather meal or Menhaden fish meal; DM intake was restricted at approximately 0.7 kg/day. Results of this experiment indicate that dietary characteristics promoting high growth or BW gain may not be those most conducive to high mohair growth. In this particular instance, a diet with supplemental fish meal resulted in greater ADG than diets with feather, corn gluten or cottonseed meals, whereas corn gluten meal yielded greatest mohair growth. Further research is necessary to fully understand how dietary properties and nutrient status affects BW gain and mohair growth by yearling Angoras.

Seasonal fleece growth and follicle activity of US Angora does subjected to different nutritional planes

A. J. Litherland, C. Toerien, T. Sahlu, P. Lee, and A. L. Goetsch

Small Ruminant Research. In Press. 2000.

Unlike its seasonally shedding ancestor, the Angora goat and most domestic sheep produce fleece continually throughout the year without a visible period of shedding. Nonetheless, Angora goats of Australia and New Zealand and many domestic sheep breeds exhibit seasonal changes in fiber growth rate driven by photoperiod. There has not yet been a characterization of the seasonal mohair growth cycle in US goats. This could be of value in a number of ways. For example, if mohair growth in US Angoras is seasonal, then efficiency of feed use for mohair production could vary during the year, and most appropriate diets or supplementation strategies will differ among seasons. Hence, the objective of this experiment was to determine seasonal effects on fleece traits including fiber growth in US Angora goats. Twenty nonpregnant Angora does were used to determine seasonal effects on fleece traits including fiber growth and follicle activity. Does grazed pastures and were supplemented with a 50% concentrate diet at a level near that required for BW maintenance. Results of this study indicate that a seasonal cycle of fiber growth in US Angora goats exists. Primary follicle activity was lower in winter than summer, and clean fiber growth rate and fiber diameter were lowest in winter, greatest in summer and intermediate in autumn and spring. Fleece fiber medullation was greatest among seasons in summer, and medullated fiber diameter was greater in spring and summer than winter. These results can be used to design optimal feeding programs for mohair production and shearing times for minimal medullated fiber contamination.

Effects of mimosine on fiber shedding, follicle activity, and fiber regrowth in Spanish goats

J. Luo, A. J. Litherland, T. Sahlu, R. Puchala, M. Lachica, and A. L. Goetsch

Journal of Animal Science. In Press. 2000.

Mimosine is a pyridoxal antagonist, which inhibits DNA replication and protein synthesis; thus, it may act mainly by arresting cell division in the follicle bulb. A study on annual patterns of follicle activity in Australian cashmere goats indicated that primary follicles were largely inactive during the winter (short daylength); secondary follicles became inactive about 1 mo later and remained so for only a short period of time. This difference between follicle types may provide an opportunity to chemically defleece or remove cashmere fiber with minimal guard hair contamination. In addition, typically, cashmere goats are shorn when the mean temperature is around 10 C in the early spring. Because shorn goats are susceptible to cold stress for up to 3 mo, retention of guard hair would be very useful in cold weather. Therefore, objectives of this experiment were to evaluate the effects of mimosine infusion on fiber shedding, follicle activity, and fiber regrowth in Spanish goats. Ten 2-yr-old Spanish wethers (58.2 ± 7.21 kg BW) were used to determine effects of 2-d intravenous infusion of mimosine (beginning on January 8) on fiber shedding, follicle activity, and fiber regrowth. At 7 to 10 d after the start of infusion, all five goats infused with mimosine exhibited shedding, whereas shedding by controls was not observed. In conclusion, 2-d intravenous infusion of mimosine at 120 mg/(kg BW · d) in the winter induced cashmere shedding but had less effect on guard hairs, suggesting future potential use of chemicals such as mimosine to remove cashmere fiber.

Effects of dietary level of Leucaena leucocephala on performance of Angora and Spanish doelings

A. Yami, A. J. Litherland, J. J. Davis, T. Sahlu, R. Puchala, and A. L. Goetsch

Small Ruminant Research. In Press. 2000.

Leucaena (Leucaena leucocephala) is a drought-resistant, leguminous tree found throughout the tropics and subtropics. Leucaena leaves are readily consumed and nutritious; however, Leucaena contains toxic compounds such as mimosine. The nutritive value and toxicological effects of Leucaena with fiber-producing goats have not been extensively studied, particularly at high dietary levels. Therefore, objectives of this experiment were to evaluate effects on live weight and fiber growth by Angora and Spanish goats of different dietary levels of Leucaena compared with a diet containing a feedstuff high in ruminally undegraded protein. Thirty Angora (16 ± 2 kg initial body weight) and 20 Spanish doelings (19 ± 2 kg initial body weight), approximately 8 months of age, were used in a 10-week experiment. The control diet (CS) included 9% dry matter of formaldehyde-treated casein; other diets consisted of 15, 30, 45 or 60% DM of Leucaena leaf meal (0.75% mimosine). Results of this experiment indicate that diets containing moderate to high levels of Leucaena, at least up to 45%, can be fed to goats without adverse effects on BW gain or fiber growth or characteristics. Moreover, the lack of interaction between dietary treatment and breed (i.e., Angora vs Spanish) for most variables suggests that differences among animals in fiber production do not have appreciable impact. However, Leucaena used in this experiment was relatively low in mimosine, and factors such as the amino acid composition of ruminally undegraded protein of Leucaena deserve consideration and further study

Effects of dietary protein concentration on postweaning growth of Boer crossbred and Spanish goat wethers

I. Prieto, A. L. Goetsch, V. Banskalieva, M. Cameron, R. Puchala, T. Sahlu, L. J. Dawson, and S. W. Coleman

Journal of Animal Science. In Press. 2000.

Development of the Boer goat in South Africa focused on selection for attributes such as size, muscling, and growth rate. Greater body weight and growth rate for Boers and Boer crossbreds than for other goat breeds and types have been documented at a number of locations. However, though Boer goats can grow more rapidly than other types of goats, growth rates are less than for sheep, implying that nutrient requirements may not be markedly different from other goats. Furthermore, ad libitum feed intake by goats relative to BW is frequently greater than for cattle and sheep. Thus, the objective of this experiment was to estimate the protein requirement by determining effects of protein concentration in high concentrate diets on growth of weaned, confined Boer crossbred and Spanish wethers. Boer (3/4) × Spanish (1/4) and Spanish goat wethers, 4 to 4.5 mo of age and 17.6 and 19.4 kg initial BW, respectively, were fed 70% concentrate diets provided ad libitum for 30 wk in confinement. The concentration of crude protein in consumed dry mater was 9.3, 13.8, 17.1, and 22.1% (P1, P2, P3, and P4, respectively); supplemental protein was from soybean meal for P1 and P2 and from soybean meal plus a blend of blood, fish, and feather meals for P3 and P4. Results of this experiment indicate a similar dietary protein requirement relative to dry matter intake for growing Boer × Spanish and Spanish wethers consuming high concentrate diets in confinement. Diets with a protein concentration of 14% or greater may support greater live weight gain than a diet with 9% protein. A ruminally degraded protein concentration of 11.5% of total digestible nutrients seems adequate for unimpaired microbial digestion and protein synthesis. However, further research on protein requirements of growing meat goats is warranted, such as with dietary protein concentrations between 9 and 14% and other diet natures and production settings.

Effects of limited concentrate intake following forage on subsequent performance of lambs consuming concentrate

A. L. Goetsch and G. E. Aiken

Sheep and Goat Research Journal 15:147-153. 2000.

High-forage diets are often consumed ad lib in a growing phase, followed by ad lib intake of concentrate-based diets during finishing. However, visceral organ energy use relative to absorbed energy is greater with ad lib intake of forage-based diets than with limited or ad lib intake of concentrate. Experiments with cattle suggest that forage diets during growing phase elevates energy and nutrient use by visceral organs during the subsequent finishing period. If the length of time or magnitude of such carryover effects is appreciable, a short period of limit-feeding concentrate after growing phase ad lib intake of forage might be of benefit. This could avert or lessen high energy use by visceral organs during finishing due to prior forage consumption, and thereby increase nutrients available to peripheral tissues. Hence, the objective of this experiment was to determine effects of a short period of restricted intake of a concentrate diet following ad lib intake of forage on subsequent performance when consuming concentrate ad lib. Results of the experiment indicate that growing phase ad lib intake of forage may affect subsequent performance with ad lib intake of concentrate differently than restricted intake of concentrate. A period of restricted intake of concentrate following growing phase ad lib intake of forage could offer potential to improve later performance with ad lib intake of concentrate, compared with a shift from ad lib intake of forage to concentrate, and to a level similar to that occurring with change from growing phase restricted intake of concentrate to ad lib intake of concentrate during finishing.