Evaluation of the 5- vs. 7-day CIDR program in dairy heifers before timed artificial insemination

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dc.contributor.author Mellieon, H.I. Jr.
dc.contributor.author Pulley, S.L.
dc.contributor.author Lamb, G.C.
dc.contributor.author Larson, J.E.
dc.contributor.author Stevenson, Jeffrey S.
dc.date.accessioned 2012-09-07T15:40:41Z
dc.date.available 2012-09-07T15:40:41Z
dc.date.issued 2012-09-07
dc.identifier.uri http://hdl.handle.net/2097/14651
dc.description Dairy Research, 2011 is known as Dairy Day, 2011 en_US
dc.description.abstract Our objectives were to determine: (1) the effectiveness of an injection of PGF2α to regress the corpus luteum before initiating an timed artificial insemination (TAI) program, (2) ovulation response to gonadotropin-releasing hormone (GnRH), and (3) pregnancy outcomes in dairy heifers inseminated with conventional and gender-biased semen. Heifers (n = 545) from 3 locations (Florida, Kansas, and Mississippi) were assigned randomly to 1 of 2 treatments: (1) 25-mg prostaglandin F2α (PGF2α) injection and controlled internal drug release (CIDR) insert on day −7 followed by 100 μg of GnRH administered on day −5, and a 25-mg PGF2α injection at CIDR insert removal (7D) on day 0; or (2) 100 μg of GnRH and insertion of previously used autoclaved CIDR on day −5 and a 25-mg PGF2α injection at CIDR removal (5D) on day 0. Artificial insemination occurred after detected estrus from days 0 to 3. Those heifers not detected in estrus were inseminated on day 3 (72 hours after PGF2α) and given a second 100-μg dose of GnRH (72 hours after CIDR removal). Blood collected on days −7 and −5 was assayed to determine concentrations of progesterone and presence of a CL (progesterone ≥1 ng/mL) on d −7. Blood progesterone concentrations on days 0 and 3 were used to determine if luteolysis occurred in all heifers. Pregnancy was determined on days 32 and 60 and intervening pregnancy loss was calculated. Of those heifers in the 7D treatment having progesterone ≥1 ng/mL on day −7, the proportion having progesterone <1 ng/mL 2 days later (luteolysis) was greater (P < 0.05) than that in the 5D treatment (43.0 vs. 22.9%), respectively. A treatment by location interaction was detected for pregnancies per AI. The Kansas location had no detectable treatment differences. In contrast, the 7D treatment produced more (P < 0.05) pregnancies in the first replicate of the Florida location and at the Mississippi location. We concluded that the 5D protocol was not more effective in producing acceptable luteolysis, pregnancy, and ovulation rates compared with the modified 7D protocol. en_US
dc.publisher Kansas Agricultural Experiment Station and Cooperative Extension Service en_US
dc.relation.isPartOf Dairy Day, 2011 en_US
dc.relation.isPartOf Kansas Agricultural Experiment Station contribution; no. 12-176-S en_US
dc.relation.isPartOf Report of progress (Kansas Agricultural Experiment Station and Cooperative Extension Service); 1057 en_US
dc.subject Dairy en_US
dc.subject CIDR en_US
dc.subject Progesterone en_US
dc.subject Timed artificial insemination (TAI) en_US
dc.title Evaluation of the 5- vs. 7-day CIDR program in dairy heifers before timed artificial insemination en_US
dc.type Conference paper en_US
dc.date.published 2011 en_US
dc.citation.epage 40 en_US
dc.citation.spage 36 en_US
dc.contributor.authoreid jss en_US

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