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Evaluation of return to estrus in superovulated dairy heifers following prostaglandin treatment
THERIOGENOLOGY
EVALUATION OF RETURN TO ESTRUS IN SUPEROVULATED DAIRY HEIFERS FOLLOWING PROSTAGLANDIN TREATMENT G.W. Halbert, K.E. Leslie, J.S. Walton'. K.J. Betteridge' Departments of Population Medicine, lAnima1 and Poultry Science, 'Biomedical Science, University of Guelph, Guelph, Ontario, Canada Efficient use of embryo transfer programs in modern dairy production systems requires that optimal reproductive performance of the herd be maintained. Rapid return of superovulated donors to regular cyclicity and pregnancy is desired. The objective of this study was to evaluate the differences in return to estrus and cyclic activity following treatment with different analogues of prostaglandin F2a. One hundred and ninety flushes involving 67 Holstein or Jersey donor heifers were studied. All heifers were evaluated for ovarian response, embryo number and embryo quality. Within 24 hours of the flush procedure, each donor was assigned by formal random allocation to one of three treatment The prostaglandin treatment groups included: Treatment 1, groups. 500 pg Cloprostenol (Estrumate, Coopers Agropharm); Treatment 2, 1 mg Fenprostalene (Synchrocept B, Syntex Agribusiness); Treatment 3, 25 mg At the time of Dinoprost tromethanine (Lutalyse, Upjohn Company). treatment and 3 to 5 days later, blood samples were collected for radioimmunoassay (RIA) of serum progesterone (P4) concentrations. The RIA P values were used to determine the occurrence of luteolysis based on rebuction of serum P 4 concentration to L 1 ngfml. Observation for estrus was carried out twice daily during exercise periods. The mean response of the study population for palpable corpora lutea, embryos recovered and good quality embryos was 9.5, 5.2 and 3.1, respectively. was 12.951.4 ng/ml. At the time of treatment, the mean P4 concentration . Each donor was superovulated 2.8 times, on average, and the mean interval between flushes was 54.4t2.8 days. Numbers of animals treated and the post-treatment response variables are presented in Table 1. There were no differences between treatment groups for palpable corpora The interval from treatment to first lutea or embryos recovered. detected estrus was longer following dinoprost treatment than that of fenprostalene or cloprostenol treatments (p
JANUARY
1989 VOL. 31 NO. 1
201
EVALUATION OF RETURN TO ESTRUS IN SUPEROVULATED DAIRY HEIFERS FOLLOWING PROSTAGLANDIN TREATMENT G.W. Halbert, K.E. Leslie, J.S. Walton'. K.J. Betteridge' Departments of Population Medicine, lAnima1 and Poultry Science, 'Biomedical Science, University of Guelph, Guelph, Ontario, Canada Efficient use of embryo transfer programs in modern dairy production systems requires that optimal reproductive performance of the herd be maintained. Rapid return of superovulated donors to regular cyclicity and pregnancy is desired. The objective of this study was to evaluate the differences in return to estrus and cyclic activity following treatment with different analogues of prostaglandin F2a. One hundred and ninety flushes involving 67 Holstein or Jersey donor heifers were studied. All heifers were evaluated for ovarian response, embryo number and embryo quality. Within 24 hours of the flush procedure, each donor was assigned by formal random allocation to one of three treatment The prostaglandin treatment groups included: Treatment 1, groups. 500 pg Cloprostenol (Estrumate, Coopers Agropharm); Treatment 2, 1 mg Fenprostalene (Synchrocept B, Syntex Agribusiness); Treatment 3, 25 mg At the time of Dinoprost tromethanine (Lutalyse, Upjohn Company). treatment and 3 to 5 days later, blood samples were collected for radioimmunoassay (RIA) of serum progesterone (P4) concentrations. The RIA P values were used to determine the occurrence of luteolysis based on rebuction of serum P 4 concentration to L 1 ngfml. Observation for estrus was carried out twice daily during exercise periods. The mean response of the study population for palpable corpora lutea, embryos recovered and good quality embryos was 9.5, 5.2 and 3.1, respectively. was 12.951.4 ng/ml. At the time of treatment, the mean P4 concentration . Each donor was superovulated 2.8 times, on average, and the mean interval between flushes was 54.4t2.8 days. Numbers of animals treated and the post-treatment response variables are presented in Table 1. There were no differences between treatment groups for palpable corpora The interval from treatment to first lutea or embryos recovered. detected estrus was longer following dinoprost treatment than that of fenprostalene or cloprostenol treatments (p
JANUARY
1989 VOL. 31 NO. 1
201