Abstract | Seventy-two two year-old first calf beef heifers, maintained at the USDA Jornada Experimental Range were used to investigate supplement intake and effects of protein and fat additions to cooked molasses blocks on cow body condition (BC) and weight change (BW), butritional status and reproductive performance in in first-calf beef heifers. Cows were randomly assigned within calving date and sex of calf to one of four treatment supplements and moved into one of four pastures ranging in size from 372 to 514 ha. Nutrients provided in blocks included: 1) an energy control (C) (10% CP); 2) fat supplement (F) (10% fat from Megalac and tallow, 10% CP); 3) protein supplement (P) (27% CP formulated to be 60% ruminally undegradable protein from feater, blood and soybean meal) and; 4) P+F supplement (10% fat and 27% CP). Consumption of supplemental nutrients on a daily basis requreid block intake to be 1.4, 1.2, 1.4 and 1.5 kg/(animal x d), respectively, for C, F, P, and P+F. Mean block intake was 0.4, 0.6, 0.6, and 0.3 kg/(animal x d), respectively for C, P, F and P+F). Cow BW loss during first 74 d was mass (P= .01) in C fed cows compared with cows consuming F. |