Relations between plasma IGF-I concentrations during treatment with CIDR-based or Ovsynch protocol for timed AI and conception in early postpartum Japanese black beef cows.
We examined the relations between plasma insulin-like growth factor (IGF) -I concentrations during treatment with CIDR-based or Ovsynch protocol for timed AI and conception and plasma steroid concentrations in early postpartum Japanese Black beef cows. Cows in the control group (Ovsynch; n = 21) underwent Ovsynch protocol (GnRH analogue on Day 0, PGF(2alpha) analogue on Day 7, and GnRH analogue on Day 9), with AI on Day 10, approximately 20 h after the second GnRH treatment. Cows in the Ovsynch+CIDR group (n = 22) received Ovsynch protocol plus a CIDR for 7 days (starting on Day 0). Cows in the further treatment group (EB+CIDR+GnRH; n = 22) received 2 mg of estradiol benzoate (EB) on Day 0 in lieu of the first GnRH treatment, followed by the same treatment as in the Ovsynch+CIDR protocol. Plasma IGF-I concentrations were determined on Days -7, 0, 7, 9 and 17. Conception rates were improved in the CIDR-combined groups (both CIDR-treated groups were combined) relative to Ovsynch group (P < 0.05) for cows with low IGF-I concentrations (<1,000 ng/ml) on Days -7, 0, and 7, but improved conception rate produced by the CIDR-based protocols did not occur in cows with a high IGF-I concentration (> or =1,000 ng/ml). Plasma estradiol-17beta concentrations increased from Day 0 to 7 (P < 0.05) and were unchanged from Day 7 to 9 in the Ovsynch group with low IGF-I concentrations on Day 0, while they were unchanged from Day 0 to 7 and increased from Day 7 to 9 (P < 0.05) in the Ovsynch group with high IGF-I concentrations on Day 0 and in the CIDR-combined group. Plasma progesterone concentrations in the Ovsynch group with low IGF-I concentrations on Day 0 were higher on Day 14 than in the Ovsynch group with high IGF-I concentrations on Day 0 and in the CIDR-combined group (P < 0.05). In conclusion, CIDR-based protocols may improve conception relative to Ovsynch in early postpartum beef cows with lower plasma IGF-I concentrations at the start of the protocols. This improvement is probably due to prevention of premature increases of estradiol-17beta and progesterone concentrations, which occurred in cows with low IGF-I concentrations treated with Ovsynch, by the CIDR treatment.
Kawate
Noritoshi
N
Department of Advanced Pathobiology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, Japan. nkawate@vet.osakafu-u.ac.jp
Sakase
Mitsuhiro
M
Seo
Yasutaka
Y
Fukushima
Moriyuki
M
Noda
Masanobu
M
Takeda
Kazushi
K
Ueno
Satoru
S
Inaba
Toshio
T
Kida
Kayoko
K
Tamada
Hiromichi
H
Sawada
Tsutomu
T
D000818:Animals; D002417:Cattle; D003008:Cloprostenol / Q000008:administration & dosage / Q000494:pharmacology; D005260:Female; D005306:Fertilization / Q000187:drug effects*; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D007315:Insemination, Artificial / Q000379:methods / Q000662:veterinary*; D007334:Insulin-Like Growth Factor I / Q000187:drug effects* / Q000378:metabolism; D049590:Postpartum Period / Q000378:metabolism; D011247:Pregnancy; D011374:Progesterone / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*
D007987:Gonadotropin-Releasing Hormone; D003008:Cloprostenol; D011374:Progesterone; D007334:Insulin-Like Growth Factor I; C009936:fertirelin