Journal article

Effect of a second treatment of prostaglandin F-2 alpha during the Ovsynch program on fixed-time artificial insemination conception rates and luteolysis in split-calving, pasture-fed dairy cows

JM Rheinberger, DD Colson, DS Beggs, PD Mansell, MA Stevenson, RJ Rheinberger, MF Pyman



OBJECTIVE: To compare fixed-time artificial insemination (FTAI) conception rates and serum progesterone concentrations at the time of FTAI for cows treated with the original Ovsynch program (OV) with those treated with a modified Ovsynch (MO) program. DESIGN: This was a randomised clinical trial. METHODS: The study used five split-calving, pasture-based dairy herds in Southwest Victoria, Australia. Controls (n = 851) received the OV program: day 0 gonadotropin-releasing hormone, day 7 prostaglandin F2α (PGF), day 9 gonadotropin-releasing hormone and FTAI at day 10. The treatment group (n = 852) received a MO program with an additional prostaglandin injection on day 8. Subsets of cows from ea..

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Funding Acknowledgements

The authors thank The Vet Group, Dairy Australia, Westvic Dairy, Gardiner Foundation, BCF Ultrasound, Boehringer Ingelheim, Gribbles Laboratories, Zoe Vogels and each of the herd managers who took part in this study. This project was also supported through an Australian Government Research Training Program Scholarship.