Authors : C.A.G. Diaz , Ebru Emsen , N. T?zemen , M.Yanar , M. Kutluca and F. K?ycegz
Abstract: The objective was to compare the reproductive performances of Brown Swiss and Holstein cows and heifers synchronized for estrus using prostaglandin F 2 (PGF2 ). Primiparous and multiparous cows (45 to 75 days postpartum; Holstein n = 17, Brown Swiss n=36) and nulliparous heifers (22 to 24 months; Holstein n = 7, Brown Swiss n=12) were injected PGF2 given 11 days apart. Artificial insemination (AI) was carried out 12 h after estrus was detected following the first PGF2 injection while timed artificial insemination (TAI) was done 72h after second PGF2 injection without detecting estrus. The estrus rate at first injection was not different between two breeds. However, the estrus detection rate was relatively greater for Brown Swiss (61.1%) than for Holstein (50.8%). Conception rates followed first PGF2 injection were found higher in Holstein (51.6%) than Brown Swiss (14%). Conception rate in TAI was found low in both breeds (Holstein: 7%; Brown Swiss: 10%). In conclusion, TAI 72h after second PGF2 injection was not effective management of AI in cows and heifers without estrus detection.
C.A.G. Diaz , Ebru Emsen , N. T?zemen , M.Yanar , M. Kutluca and F. K?ycegz , 2005. Reproductive Performance and Synchronization of Estrus in Brown Swiss and Holstein Cows and Heifers Using PGF2 . Journal of Animal and Veterinary Advances, 4: 551-553.