A comparative study of the effect of 2 hormonal treatment protocols on the reproductive performance of previously anoestrous dairy cows

Abstract

The objective of this study was to compare the reproductive performance of anoestrous dairy cows treated just prior to the mating start date (MSD) with a Controlled Internal Drug Releasing Device (CIDR) which was placed intravaginaly for either 6 or 8 days, and a combination of oestradiol benzoate. Lactating dairy cows (n = 926) that had been diagnosed with anovulatory anoestrus were divided into two sub-groups. A hormonal treatment protocol that involved the use of a CIDR device containing 1.9 g of progesterone was inserted into the vagina of each cow and left intravaginally for either 6 (6-day group, n = 441) or 8 days (8-day group, n = 485). Every cow in the trial was inseminated after be..