Supplementation of dairy cows in production with a coated vitamin B complex

Introduction. The requirements of B vitamins in ruminants are satisfied by their own ability to synthesize them at ruminal level. However, genetic improvement, advances in animal nutrition, and current high levels of production can make animals not to meet their requirements. Objective. To evaluate the effect that the use of a vitamin B complex has on dairy production and the metabolism of grazing dairy cows. Materials and methods. During the second semester of 2017, thirty Jersey cows were divided into two groups that were maintained during two 30-day experimental periods. During the first period of one month, cows in the first group received 3.0 g daily of a vitamin B complex, while the cows in the other group received a placebo and for period 2 the treatments were exchanged. Dairy production and composition were measured during the whole experiment. Chemical variables such as glucose, betahydroxybutyrate, aspartate aminotransferase, urea nitrogen, and blood albumin were also measured. Results. There were no significant differences (p>0.05) with respect to milk production. In period 1, the supplemented group produced 15.8 l of milk per day; while the control group produced 16.1 l. Fat, protein, and lactose concentrations in the first period were 5.0, 3.5, and 4.4 %, respectively. In period 2, milk production was 14.1 and 13.7 l for the supplemented and non-supplemented group, respectively. No significant differences (p>0.05) were found in any of the periods for any of the analyzed parameters in blood chemistry. Glucose concentration was greater than 40 mg dl(-1) and betahydroxybutyrate concentration was greater than 2.0 mmol l(-1). Conclusion. Supplementing Jersey cows with a rumen protected vitamin B complex showed no advantage with respect to the evaluated productive variables.