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.