Pregnancy rates of dairy cows at first service: influence of gonadotropin-releasing hormone and timing of AI relative to estrus

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dc.contributor.author Stevenson, Jeffrey S.
dc.contributor.author Mee, M.O.
dc.contributor.author Scoby, R.K.
dc.contributor.author Folman, Y.
dc.date.accessioned 2012-09-07T15:50:24Z
dc.date.available 2012-09-07T15:50:24Z
dc.date.issued 2012-09-07
dc.identifier.uri http://hdl.handle.net/2097/14670
dc.description The 1989 Annual KSU Dairy Day is known as Dairy Day, 1989 en_US
dc.description.abstract We demonstrated that gonadotropin-releasing hormone (GnRH or Cystorelin®) failed to improve pregnancy rates at the first service. When GnRH injection and insemination are both carried out either in early or late estrus or if cows are bred in early estrus and given a GnRH injection later in estrus, pregnancy rates are reduced by 9 to 13 percentage points compared to breeding according to the am-pm rule without GnRH treatment (control). Pregnancy rates of cows injected with GnRH early in estrus and bred in late estrus were similar to controls injected with saline and inseminated late in estrus (46 vs 43%). Altering the time of breeding and the time of GnRH injection to either early or late estrus did not improve pregnancy rates. We continue to recommend using GnRH only for repeat breeders, because GnRH consistently improves pregnancy rates at 3rd or 4th service, but not at first services. en_US
dc.publisher Kansas Agricultural Experiment Station en_US
dc.relation.isPartOf Dairy Day, 1989 en_US
dc.relation.isPartOf Kansas Agricultural Experiment Station contribution; no. 90-140-S en_US
dc.relation.isPartOf Report of progress (Kansas Agricultural Experiment Station); 580 en_US
dc.subject Dairy en_US
dc.subject Pregnancy rates en_US
dc.subject Gonadotropin-releasing hormone (GnRH or Cystorelin®) en_US
dc.subject AI en_US
dc.subject Estrus en_US
dc.title Pregnancy rates of dairy cows at first service: influence of gonadotropin-releasing hormone and timing of AI relative to estrus en_US
dc.type Conference paper en_US
dc.date.published 1989 en_US
dc.citation.epage 51 en_US
dc.citation.spage 48 en_US
dc.contributor.authoreid jss en_US

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