some people inject pgf2@ at insemination of the dairy cow and do it just at the time of artificial insemination why they do this and what is the mechanism of the action.
please send or addrese me a referrence
Outside United States
I am not aware of a research-based recommendation for injecting prostaglandin at the time of breeding. There is research recently published from the University of Wisconsin group suggesting accessory corpus luteum or previously non-responsive corpus luteum may reduce conception risk is present at the time of breeding. Their research (Wiltbank et al., J Dairy Science 98:1-11, 2015) suggests a second prostaglandin injection between the previous prostaglandin and GnRH injections prior to breeding in a double Ovsynch estrous synchronization protocol. The mechanism here is to reduce progesterone concentration that would interfere with fertility at breeding. For more detailed information on synchronization protocols visit Dr. Paul Fricke's website: http://paulfricke.dysci.wisc.edu/