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Metabolizable Energy (ME) and Metabolizable Protein (MP) Requirements for Angora Goats

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Use this Calculator to calculate the daily energy and protein requirements for Angora goats. Enter the data into the table below and then click the Calculate Energy and Protein Requirements button. The results will be displayed in the table at the bottom of the page. If an Angora doe is in the last 2 months of gestation, click on the Gestation Energy and Protein Requirement Calculator. The ME and MP requirements will then be added to the total requirement.

Example

We will use a mature 35-kg Angora without tissue gain and 10.0 g/day of clean mohair fiber growth consuming a diet containing 9 MJ/kg dry matter (DM) of ME.
1. Choose maturity of the goat mature (> 1 year)
growing (≤ 1 year)
2. Choose gender of goat female or wether
intact male
3. Enter body weight (kg)
4. Enter tissue (non-fiber) gain (g/day)
5. Enter clean mohair fiber gain (g/day)
6.
Enter dietary ME concentration (MJ/kg DM)
or
You can use the TDN calculator below and the ME concentration will be entered automatically.
7.
(1= no adjustment; multiplicative)
8.
(1= no adjustment; multiplicative)
9.
(0= no adjustment; additive, MJ)
10.
(last 56 days of gestation)
(0= default)
ME: (MJ)

MP: (g)
11. Enter % DM in diet (default is 90%)
If an Angora doe is lactating, enter the data below:
12. Enter milk yield (kg)
13. Enter milk fat concentration (%)
14. Enter milk protein concentration (%)
To convert from English to metric system,
enter your values here.
They will be automatically entered into the table to the left.
BW
(lbs)
ADG
(lbs/day)
clean mohair fiber gain
(lbs/day)

    

To estimate the dietary ME concentration, often feed tags list the Total Digestible Nutrient (TDN) concentration. Likewise, most commercial feed laboratories estimate the TDN concentration based on various analyses, such as for crude protein and fiber fractions. The following table can be used to estimate the dietary ME concentration based on TDN concentration. The TDN concentration should be on a dry matter basis. If the TDN value is presently on an "as fed", "as is", or "air dry" basis, then this value should be divided by the dry matter (DM) concentration (e.g., 60% as fed TDN concentration / 90% DM = 66.7% TDN on a DM basis).
ME concentration (DM basis)
TDN (% of DM) MJ/kg Mcal/kg
46.3 7 1.67
53.0 8 1.91
59.6 9 2.15
66.2 10 2.39
72.8 11 2.63
79.4 12 2.87
86.1 13 3.11

The ME concentration can also be calculated with these simple formulas:
ME (MJ/kg) = TDN (%) × 0.15104 and
ME (Mcal/kg) = TDN (%) × 0.0361.

Enter TDN (%)
ME (MJ/kg)
ME (Mcal/kg)

Nsahlai et al. (2004) reported milk fat and protein concentrations of 5.2 and 4.1%, respectively, for Angora goats in early lactation.

Requirements of Angora goats for ME and MP were determined by multiple regression analyses, with independent variables of tissue and clean mohair fiber gain, as described by Luo et al. (2004). The determined ME requirements were 473 kJ/kg body weight0.75 for maintenance and 37.2 and 157 kJ/g of tissue and clean fiber growth, respectively. Determined MP requirements were 3.35 g/kg body weight0.75 for maintenance and 0.281 and 1.65 g/g of tissue and clean fiber growth, respectively. The ME requirement for maintenance was assumed to be 5% greater for goats younger than older than 1 year, and estimates were adjusted for gender as well (15% greater for intact males than for females and wethers). The estimate of DM intake necessary to supply required ME is adjusted for differences among diets in efficiencies of ME utilization for different functions. To estimate fiber growth with body weight (BW) loss, mobilized tissue energy concentration was predicted from the AFRC (1998) equation of MJ/kg = 4.972 + (0.3274 x BW, kg) and tissue energy was assumed to be used in fiber growth with the same efficiency as dietary ME.

Requirements are greater with positive tissue gain. For example, total requirements with BW change of 20 g are 8.61 MJ of ME and 70.3 g of MP. Requirements are less when tissue gain is negative, with partitioning of nutrients to support mohair fiber growth. The method of estimating requirements with negative BW change is similar to that described for dietary ME and MP requirements for lactating goats. For example, with BW loss of 20 g/day, ME and MP requirements are 7.0 MJ and 59.4 g, respectively.

Metabolizable protein requirements are preferable compared with CP because they consider how feedstuffs vary in the extent to which proteins are degraded in the rumen (or the extent of passage to the small intestine of intact feed protein) and dietary and animal characteristics that impact the quantity of microbial protein that is synthesized in the rumen and flows to the small intestine.

However, in many instances there may not be adequate knowledge about these dietary properties to directly predict the amount of MP resulting from a given level of consumption of a particular diet. If such information is know, then the Calculator entitled "Metabolizable Protein (MP) Intake Based on Estimates of Ruminally Undegraded Protein (UIP) and Microbial Protein Synthesis" can be employed. If not, then a simple means of determining how requirements for MP relate to those for CP can be used. In this regard, NRC (2000) suggested that MP requirements can be reasonably well translated or projected to CP needs for most practical purposes with some assumptions regarding the extent of ruminal degradation of dietary CP. It was suggested that CP requirements can be determined through dividing MP needs by values from 0.64 to 0.80, which apply to diets with 0 and 100% UIP, respectively. Typically, diets with 0 or 100% of CP degraded (or undegraded) in the rumen are not fed. Thus, CP requirements have been calculated from MP for diets containing CP that is digested in the rumen (DIP; degraded intake protein) with extents of 80, 60, and 40%, which equates to concentrations of UIP of 20, 40, and 60%, respectively. A diet with 20% UIP would probably be one of fresh forage that typically has CP extensively degraded in the rumen. A diet with 40% UIP might be one with a mixture of concentrate (e.g., high level of corn) and forage. A diet with 60% UIP would have a moderate to high level of concentrate, and perhaps with some feedstuffs such as blood, feather, fish, or corn gluten meals that have considerable protein that passes from the rumen intact. Likewise, pelletizing usually increases the dietary UIP concentration.

In our example, mature 35-kg Angora without tissue gain and 10.0 g/day of clean mohair fiber growth would require a total of 7.87 MJ or ME (6.30 MJ for maintenance + 1.57 MJ for fiber) and 64.7 g of MP (48.2 g for maintenance and 16.5 g for fiber). CP requirements would be 96.3, 92.2, and 87.9 g for the mature Angora with 0 ADG for 20, 40, and 60% UIP diets, respectively. On basis of the estimate of DM intake necessary to satisfy the total ME requirement, the dietary CP concentration is 10.6, 10.1, and 9.7% for quantity of DM for 20, 40, and 60% UIP diets, respectively.

MP requirement for maintenance (g):
MP requirement for tissue gain (g):
Dietary MP used for fiber gain (g):
Dietary MP used for maintenance (g):
Sum of dietary MP used for maintenance, tissue, and fiber (g):
MP requirement for gestation (g):
MP requirement for lactation (g):
Sum of dietary MP used for maintenance, tissue, fiber, gestation, and lactation (g):

ME requirement for maintenance (MJ):
ME requirement for tissue gain (MJ):
Dietary ME used for fiber gain (MJ):
Dietary ME used for maintenance (MJ):
Sum of dietary ME used for maintenance, tissue, and fiber (MJ):
ME requirement for gestation (MJ):
ME requirement for lactation (MJ):
Sum of dietary ME used for maintenance, tissue, fiber, gestation, and lactation (MJ):

DM intake for dietary ME requirement (kg):
Adjusted DM intake for dietary ME requirement (kg):
Adjusted DM intake for dietary ME requirement (% BW):
Adjusted as fed intake for dietary ME requirement:
Adjusted as fed intake for dietary ME requirement (% body weight):
Total dietary CP requirement, diet with 20% UIP and 80% DIP (g/day):
Total dietary CP requirement, diet with 40% UIP and 60% DIP (g/day):
Total dietary CP requirement, diet with 60% UIP and 40% DIP (g/day):
Total dietary CP requirement, diet with 20% UIP and 80% DIP (% DM):
Total dietary CP requirement, diet with 40% UIP and 60% DIP (% DM):
Total dietary CP requirement, diet with 60% UIP and 40% DIP (% DM):

To determine if consumption of a calculated amount of a specific diet necessary to meet ME or MP requirements is possible, the Angora Goat Feed Intake Calculator can be used. However, this Feed Intake Calculator was based on data with Angoras not lactating or in the last 56 days of pregnancy and, therefore, its use in such instances may not be appropriate.


(maintenance energy based on body weight alone)
or

(adjusted maintenance energy)

Sources used in this calculation method are:

AFRC. 1998. The Nutrition of Goats. CAB International, New York, NY.

Luo, J., A. L. Goetsch, I. V. Nsahlai, T. Sahlu, C. L. Ferrell, F. N. Owens, M. L. Galyean, J. E. Moore, and Z. B. Johnson. 2004. Prediction of metabolizable energy and protein requirements for maintenance, gain and fiber growth of Angora goats. Small Ruminant Research 53:231-252.

Nsahlai, I. V., A. L. Goetsch, J. Luo, Z. B. Johnson, J. E. Moore, T. Sahlu, C. L. Ferrell, M. L. Galyean, and F. N. Owens. 2004. Metabolizable energy requirements of lactating goats. Small Ruminant Research 53:253-273.

Sahlu, T., A. L. Goetsch, J. Luo, I. V. Nsahlai, J. E. Moore, M. L. Galyean, F. N. Owens, C. L. Ferrell, and Z. B. Johnson. 2004. Nutrient requirements of goats: developed equations, other considerations and future research to improve them. Small Ruminant Research 53:191-219.