Resynchronizing estrus and ovulation in open cows and heifers

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dc.contributor.author Tiffany, S.M.
dc.contributor.author Stevenson, Jeffrey S.
dc.date.accessioned 2010-12-01T22:36:09Z
dc.date.available 2010-12-01T22:36:09Z
dc.date.issued 2010-12-01
dc.identifier.uri http://hdl.handle.net/2097/6738
dc.description.abstract We compared outcomes of two protocols used to resynchronize estrus and ovulation in dairy females after found open at pregnancy checks. Replacement heifers and lactating cows in which AI occurred 41 ± 1 day earlier were presented every 2 to 3 weeks for a pregnancy check by ultrasonography. Ovaries were scanned, follicles were mapped and sized, presence of corpus luteum was noted, and GnRH was injected (day 0) . Females received PGF2" 7 days later (day 7) and then were assigned randomly to either receive estradiol cypionate (ECP) 24 hours after PGF2" (day 8; Heatsynch; n = 230) or a second GnRH injection after PGF2" (day 9; Ovsynch; n = 224). Those detected in estrus were inseminated, whereas the rest received a timed AI (TAI) between 65 and 74 hours after PGF2". Few females (5.1%) were inseminated between open diagnosis and day 8. On day 10, more ECPthan GnRH-treated females were inseminated after detected estrus (24 vs. 6%). Overall, more Ovsynch than Heatsynch females received a TAI (82 vs. 62%). Conception rates tended to be greater for females inseminated after estrus (37%) than after TAI (29%), and the tendency was more pronounced for those treated with Heatsynch (41 vs. 27%) than for those treated with Ovsynch (33 vs. 31%). Conception rates for females having elevated progesterone 7 days after the not-pregnant diagnosis were greater than conception rates of those having low progesterone in Heatsynch (42%; n = 133 vs. 25%; n = 55) and Ovsynch protocols (33%; n = 142 vs. 15%; n = 45). Conception rates were greater in heifers than in lactating cows (43 vs. 28%), regardless of protocol employed. Although overall pregnancy outcomes were similar in response to either the Ovsynch or Heatsynch protocol, inseminations performed after detected estrus before the scheduled TAI reduced days to eventual conception and tended to increase conception rates, particularly after Heatsynch. en_US
dc.publisher Kansas State University. Agricultural Experiment Station and Cooperative Extension Service en_US
dc.relation.isPartOf Dairy Day, 2004 en_US
dc.relation.isPartOf Kansas Agricultural Experiment Station contribution; no. 05-112-S en_US
dc.relation.isPartOf Report of progress (Kansas State University. Agricultural Experiment Station and Cooperative Extension Service); 941 en_US
dc.subject Dairy en_US
dc.subject Synchronized estrus en_US
dc.subject Ovulation en_US
dc.subject Cysts en_US
dc.title Resynchronizing estrus and ovulation in open cows and heifers en_US
dc.type Conference paper en_US
dc.date.published 2004 en_US
dc.citation.epage 76 en_US
dc.citation.spage 70 en_US
dc.contributor.authoreid jss en_US

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