USE OF SENSORY ADDITIVES TO MASK BITTER TASTE IN CALF MILK REPLACERS

There are several feed additives used for dairy calves that cause palatability problems. A model to cause milk replacer (MR) aversion to dairy calves was developed. The model consisted on adding 30 g/kg of a mix of commercial products with bitter taste (Bittermix) to the MR, and animals who received Bittermix (BM) had more MR refusals, and a decrease in the MR intake rate. To evaluate the potential of 2 sensory additives differing in the sweet fraction to mask BM aversion in the MR, 37 Holstein male calves (6.5 ± 0.93 d of age and 40.2 ± 1.40 kg of BW) were raised under the same conditions following a common MR (25.3% CP, 21.1% fat) feeding program. When calves (38.5 ± 1.12 d of age and 57.7 ± 1.70 kg of BW)were able to consume 8 L/d at 12.5% DM concentration in 2 feedings, the aversion test was performed adding one of the following products to the MR: no supplementation (CTRL; n = 9); BM at the dose of 30 g of BM/kg of MR; (BM; n = 9); BM plus sensory additive 1 at the dose of 2 g/kg of MR (SA1; n = 10); and BM plus sensory additive 2 at the dose of 2 g/kg of MR (SA2; n = 9). The aversion test lasted 7 d, and MR intake and time devoted to consume the MR were recorded at each feeding throughout the aversion week. Data were analyzed with a mixed-effects model accounting the fixed effects of MR supplementation, feeding during the aversion week, and their interaction, and calf as random effect. The incidence of MR refusals was analyzed with a generalized mixed model considering treatment as fixed effect. The incidence of refusals and time devoted to consume the MR were similar in all 4 treatments. However, the eating rate of calves supplemented with SA2 was similar to CTRL calves, in contrast to calves supplemented with SA1 that had similar eating rate to BM calves. Sensory additive 2 was able to revert the aversion effects of BM exhibiting a similar MR eating rate than CTRL calves.