categoría: feed additives
autores: l. m. gómez, p. aguirre, f. bargo, g. tedó, and i. ipharraguerre
libro/revista:journal of dairy science, volume 100, supplement 2 (abstract: m154).
forty-five holstein dairy cows (147 d-in-milk and 544 kg bw on average) were assigned to a 3 × 3 latin square design replicated 15 times to evaluate the effect of a sensory additive (proefficient, pe; lucta sa, barcelona, spain) on milk response to concentrate supplementation on pasture. cows were blocked by parity in 15 blocks and within blocks randomly assigned to one of 3 treatments: 0 kg/d concentrate (0c); 5 kg/d control concentrate (cc); and 5 kg/d cc with 30 g/d of pe (pec). cows grazed a kikuyu (pennisetum clandestinum) pasture for 84 d in 3 28-d periods. targeted pasture allowance was 35 kg dm/ cow. pasture averaged 24.2% cp, 55.5% ndf, and 60.3% in vitro dm digestibility (ivdmd). concentrates were fed twice daily at milking. concentrate (44.3% corn, 11.2% wheat bran, 10.0% corn gluten feed, 8.6% rice meal, 8.4% soybean meal, 8.0% of sunflower meal, 9.5% mineral premix) averaged 18.4% cp, 17.8% ndf, and 85.5% ivdmd. data were analyzed using a mixed model that included the fixed effects of treatment, block, period, their 2-way interactions, and the random effect of cow within block. on average, supplementation with the starchbased concentrate increased (p < 0.05) milk yield at 6.2 kg/d compared with 0c (15.9 vs. 22.1 kg/d, sem 0.51). however, cows supplemented with pec produced more (p < 0.05) milk than cc cows (22.7 vs. 21.4 kg/d, respectively; sem 0.51). milk production response to concentrate supplementation was improved at 15% (p < 0.05) by the addition of pe into the concentrate (1.32 kg vs. 1.15 kg milk/kg concentrate for pec and cc, respectively). concentrate supplementation reduced (p < 0.05) milk fat percentage (3.69 vs. 3.93%, sem 0.065) and milk urea n (17.0 vs. 19.3 mg/dl, sem 0.45). milk fat and protein yield were increased (p < 0.05) by concentrate supplementation (0.794 vs. 0.620 kg/d, sem 0.022 and 0.686 vs. 0.497 kg/d, sem 0.016; respectively) compared with cc. the milk response triggered by pe might be associated with a reduction in the substitution rate of cc for pasture.