Estrus synchronization of replacement beef heifers by using GnRH, prostaglandin F2α (PGF), and progesterone (CIDR): a multi-location study

K-REx Repository

Show simple item record

dc.contributor.author Larson, J.E.
dc.contributor.author Lamb, G.C.
dc.contributor.author Geary, T.W.
dc.contributor.author Stevenson, Jeffrey S.
dc.contributor.author Johnson, Sandra K.
dc.contributor.author Day, M.L.
dc.contributor.author Kesler, D.J.
dc.contributor.author DeJarnette, J.M.
dc.contributor.author Landblom, D.G.
dc.contributor.author Whittier, D.
dc.date.accessioned 2010-08-03T17:51:44Z
dc.date.available 2010-08-03T17:51:44Z
dc.date.issued 2010-08-03T17:51:44Z
dc.identifier.uri http://hdl.handle.net/2097/4403
dc.description.abstract Our objectives were to determine whether a fixed-timed artificial insemination (TAI) protocol could yield similar fertility rates to a protocol requiring detection of estrus and whether an injection of gonadotropin hormone-releasing hormone (GnRH) at CIDR (vaginal insert containing progesterone) insertion enhances pregnancy rates. Replacement beef heifers (n=2,077) from 12 locations were assigned randomly to each of four estrussynchronization protocols. All heifers received a CIDR for 7 days, and an injection of prostaglandin F2α (PGF) on the day of CIDR removal. For treatment EAI, heifers were observed for estrus for 84 hours after PGF administration and were inseminated 6 to 12 hours after observed estrus. Any heifer not detected in estrus was injected with GnRH, followed by TAI. For treatment GnRH+EAI, heifers were treated as those for EAI, but also received GnRH at the time of CIDR insertion. For treatment TAI, heifers received a single TAI at 60 hours after PGF administration. For treatment GnRH+TAI, heifers were treated as those for TAI, but also received GnRH at CIDR insertion. The percentage of heifers cycling at the initiation of estrus-synchronization was 91%; the percentage of cycling heifers among locations ranged from 78 to 100%. Overall pregnancy rates among locations ranged from 38 to 74%. Pregnancy rates were 57.3, 54.5, 53.1, and 49.1% for GnRH+EAI, EAI, GnRH+TAI, and TAI, respectively. Although no statistically significant differences in pregnancy rates among treatments were observed, the GnRH+EAI treatment achieved the numerically greatest pregnancy rates. In addition, the GnRH+TAI protocol provides an alternative that allows producers to synchronize heifers without detection of estrus. en_US
dc.publisher Kansas State University. Agricultural Experiment Station and Cooperative Extension Service en_US
dc.relation.isPartOf Cattlemen's Day, 2004 en_US
dc.relation.isPartOf Kansas Agricultural Experiment Station contribution; no. 04-242-S en_US
dc.relation.isPartOf Report of progress (Kansas State University. Agricultural Experiment Station and Cooperative Extension Service); 923 en_US
dc.subject Beef en_US
dc.subject Estrus synchronization en_US
dc.subject GnRH en_US
dc.subject Prostaglandin F2α (PGF) en_US
dc.subject Progesterone (CIDR) en_US
dc.title Estrus synchronization of replacement beef heifers by using GnRH, prostaglandin F2α (PGF), and progesterone (CIDR): a multi-location study en_US
dc.type Conference paper en_US
dc.date.published 2004 en_US
dc.citation.epage 6 en_US
dc.citation.spage 3 en_US
dc.description.conference Cattlemen's Day, 2004, Kansas State University, Manhattan, KS, March 5, 2004 en_US
dc.contributor.authoreid jstevens en_US
dc.contributor.authoreid sandyj en_US

Files in this item


Files Size Format View

This item appears in the following Collection(s)

Show simple item record