Utilização da somatotropina recombinante bovina (rbST) na produção de búfalas leiteiras criadas no estado do Pará.

Abstract

Although some studies have been conducted to verify the influence of recombinant bovine somatotropin (rbST) on milk composition and blood metabolites in dairy cows, there are still insufficient information about the action of this hormone in buffaloes. Therefore, this study aimed to evaluate the effect of rbST on the productive performance of dairy buffaloes raised in the State of Pará The experiment was conducted in a farm located in the mesoregion of the Northeast of Pará. They were used 18 adult buffaloes from different genetic groups in their most arrays Murrah (Bubalus bubalis L.) or predominantly genetic Murrah crossbred multiparous, subject to the same system of grazing and nutritional managements. After selection, the animais were assigned to two groups according to their average milk production and breed. The first group (rbST) was composed of nine animais that received 500 mg of rbST every 14 days, subcutaneously, in ischio-rectal fossa, alternating left and right sides of each application. The second group (control) consisted of nine buffaloes that did not receive rbST treatment. Weekly, ali buffaloes were subjected to blood collections and sample milk, and measurement of milk production, weight and body condition score, grouped according to the lactation period: 63 -I 70, 70 -I 77, 77 -I 84, 84 -I 91 and 91 -I 98 days of lactation. Descriptive statistics of the data, represented by arithmetic means and coefficients of variation (CV) of each treatment was obtained by Means procedure of SAS version 9.2. Production variables and others from laboratory tests were analyzed as repeated measures, referring to the moments of data collection (time) according to each treatment (control and rbST), using the command Repeated generated by the GLM procedure of SAS. When the sphericity premiss was not observed (P <0.05), the probability of time (P time) and interactions of treatments over time (P trat * time) were corrected by Greenhouse-Geisse Epsilon test. The comparison between group means within each time (P) was performed using the mean test Least Square Means (LSMeans) of SAS. Was used a significance levei of 5% for ali tests. The average of the studied parameters, according to the experimental group (treatment and control): Body condition score (3.46 and 3.43), body weight (546.54 and 514, 52 kg), milk production (7, 51 and 7.37 kg), fat (6.12 and 5.94%), protein (3.82 and 3.66%), lactose (4.98 and 5.03%) total solids (15.87 and 15.61%) non fat solids (7.35 and 7.37%), somatic cell count (411.38 and 231 .IA million cells / mL), pH (6.95 and 6.97) and electroconductivity of milk (3.08 and 3.03 mS / cm) and plasmatic glucose (70.78 and 68.94 mg / dL), respectively. The administration of recombinant bovine somatotropin did not influence the production índices (body weight, body condition score and milk production), the physico-chemical composition of water buffalo milk (fat, protein, lactose, total solids, non fat solids content, pH, somatic cell count, density and electroconductivity) and plasma leveis of glucose in dairy buffaloes.