EFEITO DA SUPLEMENTAÇÃO PARENTERAL DE VITAMINA E NO PRÉ-PARTO SOBRE A EFICIÊNCIA REPRODUTIVA DE VACAS LEITEIRAS EFFECT OF PREPARTUM PARENTERAL SUPPLEMENTATION WITH VITAMIN E ON THE REPRODUCTIVE EFFICIENCY OF DAIRY COWS

SUMMARY Eighty-nine Jersey cows were used to determine the effect of the parenteral administration of vitamin E on the reproductive efficiency. Forty-four of these cows were treated intramuscularly with 3000 UI of vitamin E, whereas 45 were given isotonic saline solution (0.9%) instead, at days 60, 45, 30, and 15 before the date of calving. The results for the treated and control groups were, respectively: placental retention: 9.1 and 6.7%, metritis: 15.9 and 15.6%, pregnancy rate: 68 and 82%, first service conception rate: 66.7 and 51.4%, calving-to-first-estrus interval: 30.8±8.17 and 31.2±7,40, calving-to-first-service interval: 63.8±16.27 and 58.7±12.97, number of services per conception: 1.5±0.85 and 1.7±0.87, calving-to-conception interval: 79.7±31.83 and 81.3±38.38. There was no significant difference (P>0.05) between the experimental groups in the studied variables. The relationship between the occurrence of placental retention and metritis was positive, and has also influenced the calving-to-first-service interval and pregnancy rate, but not calving-to-first-estrus interval, number of services per conception, and calving-to-conception interval. Metritis did not influence the studied reproductive functions. It was concluded that the administration of vitamin E before the date of calving did not play a role in reproductive efficiency.