Efeito da somatotropina bovina recombinante (rBST) sobre o desempenho produtivo e reprodutivo de vacas da raça Holandesa

The Influence of Recombinant Bovine Somatotropin (rbST) on the Metabolic Profile and Milk Composition of Lactating Murrah Buffalo

The use of recombinant bovine somatotropin (rbST) leads to an increase in variable amounts of milk production in buffalo, but there is a lack of information on the influence of rbST on their metabolism. This study looked at the effects of a single 500 mg dose of rbST on the lipid profile, liver and kidney function, and physical, chemical, and cellular constitution of milk in 14 buffalo over 14 days, from the 100th day of lactation, compared with 14 animals in a control group. From the first day after rbST, there was a rise in beta-hydroxybutyrate (β-HBO), possibly due to higher dry matter intake or the biotransformation of NEFA into β-HBO. The treatment did not influence blood glucose, non-esterified fatty acids (NEFAs), triglycerides, cholesterol, total protein, albumin, AST, GGT, bilirubin, urea, or creatinine levels. In 71.3% of the buffalo, there was a gradual increase in milk production, with the maximal response occurring in the first week followed by a gradual decrease, whilst in 21.4%, the increase in production occurred between 7 and 10 days. Only 7.1% of the animals did not respond. On the 3rd, 5th, 7th, and 10th days after treatment, an increase was found in daily milk production between the two groups equal to 1.04, 1.52, 1.42, and 1.06 L, respectively. In relative terms, this means an increase in milk production, respectively, of 15.1%, 21.0%, 19.8%, and 15.1%. The constitution of the milk showed no difference in the amounts of fat, lactose, total solids, or somatic cell count; however, on the third day after rbST administration, there was a decrease in protein. Notably, from the fifth day, the protein values showed no statistical difference. It can be concluded that the use of rbST in buffalo from the 100th day of lactation is metabolically safe since the treatment neither caused imbalances in fat metabolism nor overloaded the liver or renal function, and the changes in milk composition were transient and limited to a decrease in milk protein.

Effects of bovine somatotropin on productive performance and Minas Padrão cheese

We aimed to evaluate the effects of two brands of bST (bovine somatoropin) on productive performance and on Minas Padrão cheese yield. Fifteen Girolando cows with more than 60 days of lactation were used. The animals were distributed in a randomized block design, according to days in milk, with three treatments (somatotropin A, somatotropin B, and control). The animals received a balanced diet with commercial concentrate and corn silage as roughage. It was measured milk yield and composition, dry matter intake, body condition score (BCS), and feeding behavior; it was compared by Tukey at 5.0% of significance level. Physical-chemical composition of Minas Padrão cheese was obtained from the different treatments, was also measured, being evaluated in a completely randomized design, and compared by Tukey at 1.0% of significance level. The dry matter intake per body weight lower in control treatment (p < 0.05) was equal to 2.85, somatotropin A was equal to 3.17, and somatotropin B was equal to 3.17. Animals that received bST showed higher milk production (p < 0.05), with control being 17.56 kg/day, somatotropin A 21.12 kg/day, and somatotropin B 20.69 kg/day. The physical-chemical composition of milk showed significant differences (p < 0.05) for the fat, protein, and dry extract contents. The somatotropin applications also influenced the BCS (p < 0.05) and the feeding behavior in time for total intake, time spent with rumination, and idleness. The application of bST increased milk yield and technical and economic yields of Minas Padrão cheese did not show significant differences between treatments.