Crude glycerin in diets for Nelore heifers on pasture in dry season

Abstract

This study aimed to evaluate the inclusion of crude glycerin (CG) in the diet of Nellore heifers grazing Brachiaria brizantha during the dry season, on nutrients intake and digestibility, performance, reproductive efficiency and economic viability. Sixty Nelore heifers with initial average weight of 285.89 ± 18.74 kg and approximately 19 ± 2 months of age, were distributed in a completely randomized design with five diets containing 0.0; 4.0; 8.0; 12.0 and 16.0% of CG inclusion in the diet. The average dry matter (DM) daily intake showed decreasing linear effect (P <0.05), whereas for one % inclusion of GB decreased to 0.097 kg of DM intake day-¹. The DM digestibility of the diet, had no significant effect (P>0.05), with a mean value of 50.93%. The average daily gain (ADG) of heifers showed decreasing linear effect (P<0.05). For one % of GB included in the diet was reduced 0.0065 kg day-¹ of gain. The reproductive rates (rate of pregnant and semen doses by pregnant), were not affected (P>0.05) by dietary inclusion of GB, with average values of 75% and 1.29 doses pregnant-¹, respectively. The economic viability indicators were not positive in the short and medium term. Supplements for over 0.7% of the PC in animals maintained in Brachiaria brizantha with low nutritional quality, it is not recommended to include GB, since its inclusion in any level reduced around 15% weight gain. However, depending on the cost of coproduct, it can be includes up to 16% in the diet, even considering this drop in performance.