Substituição de farelo de soja por proteína de leveduras na dieta de vacas em lactação manejadas em pastejo rotacionado

Abstract

The objective of this study was to evaluate the substitution of soybean meal by yeast-derived protein (YDP) in the diet of Girolando (F1) cows under rotational grazing (Pannicum maximum cv. Mombasa) and the effects on milk production and percentage of solids, nitrogen use efficiency, blood parameters and feed efficiency. Sixteen Holstein-Gir (1/2), multiparous cows with a mean production of 30 kg were used, with a mean weight of 489±22 kg and 62±26 days in milk at the beginning of the experiment, in a 4X4 Latin Square. The experimental diets consisted of substitution of soybean meal with yeast protein (YDP) in the same proportions, treatment YDP0 (without the product), treatment YDP150 (substitution of 150 grams of soybean meal by DEMP®), treatment YDP300 (substitution of 300 grams of soybean meal by DEMP®) and YDP450 treatment (substitution of 450 grams of soybean meal by DEMP®). The replacement of soybean meal by YDP for dairy Girolando (F1) cows, in rotational grazing, presented negative linear effect for milk and solids production, affected the NDF consumption, without affecting the total consumption nor the digestibility of the diet. There was no difference in nitrogen balance and microbial protein production among treatments. Feed efficiency values were lower in high soybean meal substitutions by YDP.