Performance of Holstein dairy calves fed starter diet with incremental vinasse proportion

Abstract

This experiment evaluated the progressive inclusion of vinasse in calf starter diet on performance, rumen fermentation, and blood metabolites. Forty-eight Holstein calves weighing an average of 41.5 ± 2.20 kg were used in a completely randomized design and assigned to 4 dietary groups: no vinasse inclusion (V0), 4% of dry matter (DM) vinasse inclusion (V4), 8% of DM vinasse inclusion (V8), and 12% of DM vinasse inclusion (V12). Each treatment group comprised 12 calves that were balanced for sex of calves. Vinasse was added to the starter feed to replace soybean meal and wheat bran. Calves were gradually weaned from day 64 to 70, and the experiment continued until day 90. Starter feed, total DM, and metabolizable energy intakes during the post-weaning and overall periods responded cubically to vinasse inclusion level, and the greatest intakes were observed in V8-fed calves. As the dietary inclusion of vinasse increased, average daily gain (ADG) increased linearly, quadratically, and cubically during pre-weaning, post-weaning and overall periods, respectively. This resulted in pre-weaning and overall feed efficiency (FE) increasing linearly, and post-weaning FE tended to increase linearly with increasing inclusion level of vinasse in the starter diet. Weaning body weight (BW) tended to increase and final BW increased linearly as the dietary inclusion of vinasse increased. Weaning and final hip width responded quadratically, with V4-fed calves showing the greatest values. Weaning and final body barrel decreased linearly and tended to decrease linearly, respectively, as the dietary inclusion of vinasse increased in the starter diet. Ruminal pH on day 45 was not different among treatments, but pH on day 85 responded quadratically, with the highest pH observed in V8-fed calves. Ammonia and total VFA concentrations (days 45 and 85) were not different across treatments. Acetate concentration on day 85 increased linearly from 50.3 to 55.5 mol/100 mol, as vinasse proportion increased from 0 to 12% of DM in the calf starter, but the inverse trend was observed with propionate molar proportion. Butyrate, isobutyrate, and isovalerate concentrations measured on day 45 were not different among treatments, but the lower values on day 85 were observed with V4 and V8-fed calves. Blood metabolites on days 60 and 80 remained unaffected between treatments. In conclusion, vinasse is recommended at 8% of DM in the calf starter diet as this level improved calf performance and rumen fermentation.