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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