| Popis: |
Growth and plasma hormone and metabolite levels were used to compare the effects of nutrient restriction and realimentation on six Suffolk (S), six Gulf Coast Native, (G) and seven S×G crossbred lambs. Shorn lambs were individually fed a 10% CP diet consisting of 20% cottonseed hulls, 74% ground corn, 1% soybean meal, 3% fish meal, 1.1% oyster shell flour, 0.5% urea, and 0.4% trace mineral salt and vitamin A, D, and E mixture. Lambs were fed at 110% of maintenance, 200% of maintenance, or had ad libitum access to feed during periods 1, 2, and 3, respectively. Each period was 28 d in length. Breed did not affect (P>0.25) weight change during nutrient restriction or realimentation. All lambs lost weight during the first period. The calculated NEm of weight loss and 10% feed intake above maintenance suggests an 88% increase in maintenance energy requirement at 11.6 ± 0.9°C average temperature. Similar shorn G lambs maintained weight even though fed at 200% of maintenance, suggesting a 99% increase in NEm. Plasma cortisol was lower (P |
