Effect of using trace minerals (copper, zinc, selenium, and manganese) and vitamins A and E on the metabolic profile of Holstein cows in the transition period

The aim of this study was to assess the metaphylactic effect of subcutaneous doses of trace minerals (copper, zinc, selenium, and manganese) and vitamins A and E on biochemical (NEFA, BHBA, fructosamine, urea, triglycerides, HDL, and calcium) and hormonal parameters (cortisol, insulin, and IGF-1) of Holstein cows in the transition period. Sixty animals kept in a semi-confinement system, with an average production of 22 liters of milk per day (Farm 1) and 24 liters of milk per day (Farm 2) and a diet according to NRC (2001) with a low metabolic challenge, were divided into two groups: a treatment group, supplemented with trace minerals and vitamins (MTVG) (n=30), and a control group (CG) (n=30). The collection of blood samples was performed at the moments M1 (21 days prepartum), M2 (14 days prepartum), M3 (7 days prepartum), M4 (parturition day), M5 (7 days postpartum), M6 (14 days postpartum), and M7 (21 days postpartum). The experimental design was a randomized block design and the data were submitted to analysis of variance with repeated measures in time within the random variable cow. Differences were considered significant at 5% significance level and trend at 10% level. No difference was observed between treatment and the interaction treatment × day in the assessed parameters. However, some variables showed a significant difference of day. NEFA levels (P < 0.0001) were higher on the parturition day. BHBA concentrations were higher after parturition (P=0.0031), with a peak at the third week of lactation. Fructosamine showed increasing values until the parturition day (P=0.0373), in which higher concentrations were observed. Average values of HDL were higher at 21 days postpartum (P < 0.0001). Triglycerides levels remained high during the prepartum period but showed a sudden drop on the parturition day (P < 0.0001), with lower values postpartum. Regarding serum calcium and IGF-1, lower values were observed on the parturition day (P < 0.001) for both parameters. Cortisol presented a difference regarding day, with higher values on the parturition day (P=0.0151). Thus, the use of trace minerals and vitamins A and E in animals with an adequate body score and low metabolic challenge presents a low response to biochemical and hormonal parameters.