UREIA NA DIETA DE VACAS EM LACTAÇÃO SOBRE A PRODUÇÃO E QUALIDADE DO LEITE

Abstract

The effects of increasing levels of urea (0.0, 0.97, 1.3 and 1.66%) were substituted for soybean meal on milk production and composition of dairy cows. Four lactating cows were used, with a mean initial production of 8.00 kg / day of milk and approximately 80 days in lactation, distributed in a 4x4 Latin square, during four experimental periods of 20 days each, fourteen days of adaptation and six days of collection. Experimental diets were composed of corn silage as single bulk and concentrate, in the ratio of 60:40 (dry matter basis). For the statistical analysis of the data, the procedures PROC MEANS and PROC GLM of SAS UNIVERSITY (2018) were used. For the analysis of variance, the F test was used at 5% of probability. To obtain the difference between the averages of treatments, the Tukey test was used at 5% of probability. The inclusion of 0,0; 0.97; 1.3 and 1.66% of urea in place of soybean meal did not generally affect milk production and composition. Treatments 2 and 4 with inclusion of 0.97% and 1.66% of urea, respectively, presented the best values of milk production and composition. In this way, it is possible the alternative use of urea to the soybean meal.