Host: Society for Reproduction and Development
A new progesterone intra-vaginal device for cattle has been developed in Argentina. The product (DIB) is Y-shaped and contains 1 g progesterone. The objective of this study was to know the effectiveness of DIB, in comparison with CIDR, in estrus synchronization of lactating dairy cows. A total of 110 Holstein Friesian cows from 22 commercial dairy farms in Yamaguchi Prefecture were used. The cows were 60d postpartum or later and were in their first to fourth lactations, and had no clinical abnormality in ovaries and uterus. The 110 cows were divided into two treated groups. One group of 54 cows was inserted into the vagina with DIB, which was removed 12d after insertion. The other group of 56 cows were treated with CIDR as same as DIB treated group. Milk samples were collected at 0, 7, 12, 14 and 21d after insertion to measure progesterone concentrations. Decrease in milk progesterone concentrations 14d after insertion (2d after removal) was considered to be positive response. Estrus was detected by visual observation by farmers with or without heat detection aids. Cows were inseminated artificially after estrus detection. Estrus detection rate within 6d after removal of CIDR and DIB was 57.1% and 44.4%, respectively. Estrus induction rate based on milk progesterone profile and expression of estrus was 64.3% and 66.7% in CIDR and DIB groups, respectively. Conception rate after AI at induced estrus was 21% in CIDR group and 19% in DIB group. It is concluded that DIB is equally effective to CIDR in estrus synchronization in dairy cows.
