|Wildeus, S - VIRGINIA STATE UNIVERSITY|
|Luginbuhl, J - NORTH CAROLINA STATE UNIV|
|Nutall, Y - VIRGINIA STATE UNIVERSITY|
|Collins, J - VIRGINIA STATE UNIVERSITY|
Submitted to: Sheep and Goat Research Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2007
Publication Date: December 1, 2007
Citation: Wildeus, S., Luginbuhl, J.M., Turner, K.E., Nutall, Y.L., Collins, J.R. 2007. Growth and carcass characteristics in goat kids fed grass and alfalfa hay-based diets with limited concentrate supplementation. Sheep and Goat Research Journal. 22:15-19. Interpretive Summary: Finishing goats in feedlots on high concentrate diets is not a widespread practice, as goats are generally used more efficiently when utilizing browse or forage. The utilization of forages by ruminants is dependent on a variety of inter-related factors that include not only forage nutritive value, but also intake and digestibility. Carcass composition in goats may be influenced by level of feed intake and diet composition, but additional information is needed on the specific effects of breed and diet on carcass characteristics. We evaluated the effect of improved nutritional value of alfalfa hay compared to mixed grass hay on animal growth and carcass characteristics in young goats of different breeds. Alfalfa-feeding improved growth rate and dressing percentage, but had no effect on other carcass characteristics, whereas sex class influenced primarily carcass fat; bucks < does < wethers. The research is useful to producers designing feeding/finishing programs that use strategic supplementation to not only manipulate the fat content of carcasses, but to alter the composition of retail cuts in the carcass of goats in order to satisfy different ethnic market needs and maximize small farm income.
Technical Abstract: Two experiments were conducted to evaluate the effect of feeding legume hay (alfalfa; Medicago sativa L.) or mixed grass hay on ADG and carcass characteristics of growing goats. In Experiment 1, 24 Spanish kids, equally representing intact male, female, and wether goats, were pen-fed ad libitum either chopped alfalfa (16.8% CP) or mixed grass hay (9.4% CP) (3 pens/diet) and a corn (Zea maise L)-soybean (Glycine max L.) meal supplement (16% CP) at 1.5% BW for 102 d. Goats were harvested at a commercial abattoir. Average daily gain (62 vs. 37 g; P<0.01), carcass weight (14.8 vs. 12.8 kg; P<0.05) and dressing percent (52.9 vs. 50.4; P<0.05) were higher in alfalfa than grass hay-fed goats, respectively. Backfat and % kidney/pelvic fat were lower (P<0.05) in bucks (0.12 cm and 1.8%) than in does (0.17 cm and 5.7%) and wethers (0.22 cm and 4.0%). In Experiment 2, 10 mo-old Boer and F1 Boer wethers (n=16) were pen-fed ad libitum either chopped alfalfa (15.2% CP) or grass hay (10.9% CP) for 84 d. Forage was supplemented with concentrate (16.3% CP) at 1% of BW. Carcass characteristics were determined as described for Experiment 1. Boer wethers fed alfalfa hay had a higher ADG (158 vs. 119 g/d; P<0.01) and dressing percentage (54.0 vs. 52.2%, P<0.05), but did not differ in other carcass characteristics. Alfalfa-feeding improved growth rate and dressing percentage, but had no effect on other carcass characteristics, whereas sex class influenced primarily carcass fat content.