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ARS Home » Research » Publications at this Location » Publication #106195
Title: INFLUENCE OF PERCENTAGE ST. CROIX ON POSTWEANING FEEDLOT PERFORMANCE

Author
item Brown, Michael
item Phillips, William

Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/1999
Publication Date: N/A
Citation: BROWN, M.A., PHILLIPS, W.A. INFLUENCE OF PERCENTAGE ST. CROIX ON POSTWEANING FEEDLOT PERFORMANCE. JOURNAL OF ANIMAL SCIENCE. 1999. 77(Suppl.1): Abstract p. 24.

Interpretive Summary: Abstract Only.

Technical Abstract: Data from 262 lambs sired by Dorset and St. Croix (SC) rams from Texel x SC, Texel x Polypay, Romanov x SC, Romanov x Polypay and SC x SC ewes were used to evaluate the effect of percentage SC on postweaning feedlot performance. Comparisons made in 1995 were 0, 25, 50, 75, and 100% SC (Analysis 1). Dorset-sired data from 1995 and 1996 were combined to provide comparisons for 0, 25, and 50% SC (Analysis 2). In Analysis 1, start weights averaged 21.2, 20.2, 20.7, 18.7, and 17.6 kg for 0, 25, 50, 75, and 100% SC, respectively. Daily gains averaged .27, .23, .20, .18, and .15 kg/d for 0, 25, 50, 75, and 100% SC, respectively. Mean ADG for 50 and 75% SC were similar with all other contrasts different (P<.05). Finished weights averaged 53.7, 52.1, 47.7, 45.0, and 39.2 kg for 0, 25, 50, 75, and 100% SC, respectively. Mean finished weights for 0 and 25% SC were similar, as were means for 50 and 75% SC, with all other contrasts significant (P<.05). In Analysis 2, start weights averaged 23.5, 22.6, and 21.9 kg for 0, 25, and 50% SC, with 50% SC less than 0% SC (P<.10). Daily gains differed for 0, 25, and 50% SC (P<.01) and averaged .22, .20, and .17 kg/d. Finished weights were similar for 0 and 25% SC (51.1, 50.2 kg) but both exceeded 50% SC (46.3 kg, P<.01). These data indicate that genetic improvement in the growth rate of SC would be desirable.