INFLUENCE OF UNDEGRADED INTAKE PROTEIN SUPPLEMENTATION ON MILK-PRODUCTION, WEIGHT-GAIN, AND REPRODUCTIVE-PERFORMANCE ON POSTPARTUM BRAHMAN COWS

Eighty first-calf Brahman heifers and 51 mature Brahman cows were allo tted to one of three diets based on parity, Sex of calf, and breed of calf sire (Angus, Brahman, or Tuli) to evaluate rumen undegraded intak e protein's (UIP) influence on production characteristics End reproduc tive performance. Supplements contained either 38.1% (low), 56.3% (med ium), or 75.6% (high) UIP. Supplements were given from d 7 to 119 afte r calving to dams grazing rye-ryegrass overseeded Coastal bermudagrass pastures and with access to Coastal bermudagrass hay. Dam and calf BW and dam body condition score were recorded on a 7, 35, 63, 91, and 11 9 after calving. Four-hour milk production was recorded on the above d ays for low (n = 18), medium (n = 19), and high (n = 18) UIP animals a nd on d 7 and 35 for the entire group. Blood for progesterone RIA was drawn weekly and on d 6, 8, 10, and 12 after an observed estrus. Mediu m UIP heifers produced more (P < .02) milk (1.18 +/- .07 kg/4 h) than high UIP heifers (.94 +/- .07 kg/4 h), but milk production in mature c ows was not influenced by diet. Low UIP dams had lower (P < .04) first -service conception rates (29.2%) than medium (57.6%) and tended (P < .10) to have lower rates than high UIP dams (54.6%). Overall pregnancy rates tended (P < .10) to be higher in medium (61.5%) and high (56.4% ) UIP groups than ih the low (43.2%) UIP group. Supplementing UIP at t he medium rate improved first-service conception rates and tended to i mprove pregnancy rates.