Efeito de duas formulações de somatotropina recombinante bovina em parâmetros produtivos, bioquímicos, comportamentais e alimentares de vacas da raça Holandês

Abstract

The use of technologies in production systems meets the growing demand to increase production efficiency in dairy cows. Thus, some strategies have been studied to increase productivity, such as the use of bovine recombinant somatotropin (rbST). Thus, the objective of the work was to evaluate the effect of the administration of two commercial forms containing 500 mg of rbST on productive, biochemical, behavioral and feeding parameters of Holstein cows. For the research, 18 secondary cows were randomly distributed in two groups with 9 animals in each treatment. The groups rbSTBoostin® (MSD Saúde Animal), with an average of 147 DIM, and rbST-Lactotropin® (Agener União Saúde Animal), with an average of 152 DIM, received a dose of 500 mg of rbST every 14 days, totaling 5 applications and 70 days trial period. Blocked animals had to meet some selection criteria, therefore, each block completed animals with lactating days (between 90 and 210), milk production in the two weeks prior to the experiment, lactation order, body condition score (ECC) and reproductive status (pregnant / not pregnant) similar in order to maintain the most homogeneous experimental conditions possible. Clinical and zootechnical evaluations were carried out at each application cycle. Blood was also collected on the 1st, 4th and 7th days of each cycle to assess circulating levels of non-esterified fatty acids (AGNE), albumin, beta-hydroxybutyrate (BHB) and glucose. Daily, milk production was measured by the DelPro ™ software (DeLaval®) for each animal milking and consumption and feeding behavior were taken through intelligent feeders (Intergado®). Animal behavior was assessed using monitoring collars (ChipInside®) individuals who daily indicate the activity time, rumination and leisure (min / day) of the animals. Weekly, milk samples were collected, in two milkings in a row, for the analysis of milk constituents and somatic cell count. The rbST-Boostin® group had the highest milk production (40.75 ± 0.47 kg / day; P = 0.03) and tended to have the highest dry matter intake (25.98 ± 0.33 kg / day; P = 0.07). In addition, animals treated with rbST-Boostin® had plasma levels higher of NEFA (0.61 ± 0.03 mmol / L; P <0.01) and in relation to glucose measurements, the rbST-Lactotropin® group tended to present higher values (62.34 ± 0.86 mg / dL; P = 0.09). As for the variation in body weight, it can be observed that the animals treated with rbST-Boostin® had greater variation (-20.67 ± 3.02 kg; P <0.01). In relation to milk constituents, the cows in the rbST-Boostin® group, higher levels of lactose throughout the experimental period (4.50 ± 0.04 g / 100g; P = 0.05). Therefore, it is concluded that cows treated with rbST-Boostin® are superior to cows treated with rbST-Lactotropin®, showing higher milk production with a tendency to have a higherintake of dry matter compared to cows treated with rbST-Lactotropin®, in addition to having higher AGNE levels.