|Hart Steven P|
|Fernandez J M|
Submitted to: Small Ruminant Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/1992
Publication Date: N/A
Citation: N/A Interpretive Summary: Goats are becoming more popular as a meat and fiber source in the Southwest U.S. The amount of research data is available for different breeds of goats is much smaller than that for other ruminant farm animals such as cattle and sheep. We examined the protein utilization by three breeds of goats, one meat type (Nubian), one milk type (Alpine) and one fiber type (Angora) fed 9, 15 or 21% protein diets. The amount of feed protein digested and retained was not different among breeds, but plasma urea-N was lower for Angora than for Nubian and Alpine goats. This study indicated there were no apparent breed differences when goats were fed protein levels between 9 and 21%.
Technical Abstract: Twelve wethers (27-33 kg and 12-14 months of age) representing meat (Nubian), milk (Alpine) and mohair (Angora) producing goats were used to evaluate breed differences in protein utilization with diets containing 9 (L), 15 (M) or 21% CP (H) and 2.4 Mcal ME/kg DM in a digestion trial. Fecal N, urine N and absorbed N as percent of N intake were not affected (P>0.05) by breed. Retained N as percent of absorbed N was not different (P>0.05) between breeds. Ruminal propionate (molar %) was lower (P<0.05) in Angora, but other ruminal VFA and ammonia-N were not affected (P>0.05) by diet or breed. Plasma urea-N increased (P<0.01) with dietary CP level (8.3, 22.0 and 33.3 mg/dl for L, M and H, respectively), and concentrations were lowest for Angoras and highest for Nubians (18.5 vs 21.2 vs 23.9 mg/dl) (P<0.01). Plasma total protein (mean 69.7 g/l), glucose (mean 83.1 mg/dl), non-esterfied fatty acids (mean 101.4 mu Eq/l) and cortisol (mean 10.8 ng/ml) were not affected (P>0.05) by breed or diet. Plasma glucagon concentrations increased (P<0.05) with increasing CP intake (72.4, 167.6 and 239.1 pg/ml for L, M and H, respectively). The study indicated that there was no apparent breed difference between Nubian, Alpine and Angora goats in nitrogen utilization when goat were fed pelleted diets containing 9 to 21% CP.