TY - JOUR
T1 - The effects of intramuscular or intravenous injections of gonadotropin releasing hormone at fixed-time artificial insemination on pregnancy rates of bos indicus beef cows
AU - Demeterco, Danilo
AU - Henry, Darren Dwayne
AU - Mercadante, Vitor Rodrigues Gomes
AU - Lamb, Graham Cliff
AU - Gaievski, Francisco Romano
AU - Weiss, Bruno
AU - Turbay, Gustavo Nascimento
AU - Segui, Márcio Saporski
AU - Weiss, Romildo Romualdo
AU - Bertol, Melina Andreia Formighieri
AU - Kozicki, Luiz Ernandes
PY - 2014
Y1 - 2014
N2 - The effect of an intramuscular versus intravenous administration of gonadotropin releasing hormone (GnRH) at fixed-time AI (FTAI) on the pregnancy rates of crossbred Bos indicus beef cows was evaluated. Pluriparous nursing calv cows (n=120) were synchronized as follows: d 0 cows received a 2.0 mg injection of estradiol benzoate (EB) and insertion of a controlled intravaginal progesterone releasing device containing 0.558 g of progesterone, d 8 removal of the progesterone device , a 0.15 mg injection of prostaglandin F2α (PGF), a 1.0 mg injection of EB, and 400 IU injection of equine chorionic gonadotropin. Fifty-four hr after PGF, all cows were exposed to FTAI and a 0.084 mg injection of GnRH was administered either via Vena caudalis (n=60), or via Longissimus dorsi (n=60). Cows were inseminated with the same sire and by a single AI technician. Pregnancy was determined by the transrectal ultrasonography on d 40 after AI. Cows receiving the intravenous administration of GnRH had higher (P = 0.04) pregnancy rates than the cows receiving the intramuscular injection of GnRH (65 vs 46.6%, respectively). It was concluded that the intravenous administration of GnRH at the time of AI improved the pregnancy rates of crossbred Bos indicus beef cows submitted to FTAI.
AB - The effect of an intramuscular versus intravenous administration of gonadotropin releasing hormone (GnRH) at fixed-time AI (FTAI) on the pregnancy rates of crossbred Bos indicus beef cows was evaluated. Pluriparous nursing calv cows (n=120) were synchronized as follows: d 0 cows received a 2.0 mg injection of estradiol benzoate (EB) and insertion of a controlled intravaginal progesterone releasing device containing 0.558 g of progesterone, d 8 removal of the progesterone device , a 0.15 mg injection of prostaglandin F2α (PGF), a 1.0 mg injection of EB, and 400 IU injection of equine chorionic gonadotropin. Fifty-four hr after PGF, all cows were exposed to FTAI and a 0.084 mg injection of GnRH was administered either via Vena caudalis (n=60), or via Longissimus dorsi (n=60). Cows were inseminated with the same sire and by a single AI technician. Pregnancy was determined by the transrectal ultrasonography on d 40 after AI. Cows receiving the intravenous administration of GnRH had higher (P = 0.04) pregnancy rates than the cows receiving the intramuscular injection of GnRH (65 vs 46.6%, respectively). It was concluded that the intravenous administration of GnRH at the time of AI improved the pregnancy rates of crossbred Bos indicus beef cows submitted to FTAI.
KW - Fixed-time artificial insemination
KW - Gonadotropin releasing hormone
KW - Intravenous intramuscular administration
UR - http://www.scopus.com/inward/record.url?scp=84902006377&partnerID=8YFLogxK
U2 - 10.1590/S1516-89132014005000016
DO - 10.1590/S1516-89132014005000016
M3 - Article
AN - SCOPUS:84902006377
SN - 1516-8913
VL - 57
SP - 361
EP - 366
JO - Brazilian Archives of Biology and Technology
JF - Brazilian Archives of Biology and Technology
IS - 3
ER -