Ultrassonografia na validação do escore de condição corporal em vacas holandês-zebu durante o período de transição e fase inicial da lactação

Abstract

The body condition score (BCS) is a method of assessment of the animal's energy reserves and it was developed based on the characteristics of mobilization/ deposition of cow’s fat cows with degree of Holstein blood Therefore, it is not known whether this methodology is appropriate for crossbred cows. Thus, the objective with this study to investigate the relationship between the back fat thickness (BFT) and the body condition score (BCS) in crossbred cows (Holstein - Zebu) during the transition period and early lactation, and to relate these findings with productive and metabolic parameters. A total of 108 Holstein - Zebu dairy cows from six farms were randomly selected and divided into three groups according to their production phase at the time: PP group (0 to 4 weeks antepartum; n = 30 animals); L4 group (0-4 weeks postpartum; n = 15 animals); L + 5 group (5-14 weeks postpartum; n = 63 animals). Correlation and regression analysis were used to describe the relationship between the BCS, BFT and body weight (BW) variables. For productive and metabolic evaluation of the animals we made a multivariate cluster analysis to order the distribution of these animals in homogeneous BFT groups within each study phase. Analysis of variance showed significant differences (P <0.05) among the three groups for the three variables BCS, BFT and BW. The BW variable showed a weak correlation with the BCS and BFT variables r = 0.28 and r = 0.38, respectively. In groups PP and L + 5 there were strong and direct correlation between BFT and BCS variables, r = 0.78 and r = 0.71, respectively. The BFT was sensitive to changes in metabolites albumin, total cholesterol and total protein. In addition to being a good indicator of the production of milk and density, as well as proportions of total solids and lactose.