Effect of replacing forage sorghum silage with biomass sorghum silage in diets for F1 Holstein × Zebu lactating cows.

Abstract

The objective of this study was to evaluate the replacement of forage sorghum silage (FS silage) with BRS 716 biomass sorghum silage (BRS 716 silage) in diet of F1 ½ Holstein × ½ Zebu cows on their nutrient intake and digestibility, ingestive behavior, nitrogen balance, and milk yield and composition. The experimental design was in two 5 × 5 Latin squares, simultaneous, composed, each, by five animals, five treatments, and five experimental periods. The study included 10 cows with an initial body weight (BW) of 544 ± 12.84 and 88 ± 14days of lactation at the beginning of the experiment. The treatments were defined by replacement FS silage at levels 0, 25, 50, 75, and 100% with BRS 716 silage. The roughage:concentrate ratio in the total dry matter (DM) of the diets was 75:25. The replacement of FS silage with BRS 716 silage reduced (p < 0.01) the dry matter intake and digestibility of dry matter, but it had not changed average milk yield (12.68kg/day; p = 0.94), feed efficiency, body weight, the score of body condition, and the average daily gain of the cows. The milk composition was not changed except casein/total protein in milk that decreased and that increased linearly milk urea nitrogen. The inclusion of BRS 716 silage increased the activities of rumination and chewing and decreased the periods of feeding and idleness. The replacement of up to 100% of FS silage with BRS 716 silage in the diet of F1 Holstein × Zebu cows does not alter average milk yield, despite changing diet intake and digestibility.