Substituição de somatotropina bovina sintética por levedura viva no desempenho produtivo de vacas leiteiras

Abstract

The use of additives in ruminant nutrition each year gains more market and aims to improve the productive efficiency of the system based on a product of natural origin. The study was conducted with the objective of evaluating the effects on the productive performance of the replacement of rBST by the addition of live yeasts for dairy cows in early lactation. The experiment was carried out on a commercial farm in the municipality of Pejuçara, RS, using 35 multiparous Holstein cows, distributed in a completely randomized design. The experimental period was 70 days with 5 periods of 14 days of evaluation. The experimental treatments were: 1) rBST (application of Lactotropin® - Elanco Saúde Animal every 14 days) and 2) LV (inclusion of 40 g/day/animal of Saccharomyces cerevisiae KA 500: 20x109 UFC/g, Kera Nutrition Animal). The data obtained were submitted to PROC MIXED of SAS 9.4 and analyzed by repeated measures over time. The experimental treatments did not influence the consumption of dry matter and nutrients, however, an effect of time was observed for the measured variables. Cows supplemented with LV showed a lower concentration of fecal starch. The experimental treatments did not influence (P> 0.05) the variables of live weight, body score condition, and milk composition. LV increased milk production (35.21 x 36.76 kg/day), milk production (kg/day) / CMS (kg/day) (1.57 x 1.61), corrected milk to 3.5% of fat (36.15 x 38.16 kg/day) and liquid energy content of milk (36.53 x 38.44 Mcal /day) and decreased somatic cell count (460 x 337 thousand/ml). Experimental treatments influenced blood metabolites, glucose (102.98 x 98.06 mg/dL), triglycerides (21.49 x 16.85 mg/dL) and AST (23.59 x 17.3 IU/mL) were higher in rBST-treated cows. Supplementation with LV improved the productive performance of dairy cows in early lactation, recommending in this way the replacement of the use of rBST.