Effect of CIDR-based protocols for timed-AI on the conception rate and ovarian functions of Japanese Black beef cows in the early postpartum period.
Our objectives were to compare: (1) conception rates (in early postpartum Japanese Black beef cows) to timed-artificial insemination (timed-AI) among Ovsynch and Ovsynch plus CIDR protocols, and a protocol that used estradiol benzoate (EB) in lieu of the first GnRH of the Ovsynch plus CIDR; and (2) the effects of these protocols on blood concentrations of ovarian steroids. Cows in the control group (Ovsynch; n=35) underwent a standard Ovsynch protocol (GnRH analogue on Day 0, PGF(2 alpha) analogue on Day 7 and GnRH analogue on Day 9), with timed-AI on Day 10, approximately 20 h after the second GnRH treatment. Cows in the Ovsynch+CIDR group (n=31) received a standard Ovsynch protocol plus a CIDR for 7 days (starting on Day 0). Cows in the third treatment group (EB+CIDR+GnRH; n=41) received 2mg of EB on Day 0 in lieu of the first GnRH treatment, followed by the same treatment as in the Ovsynch+CIDR protocol. The conception rate tended to be greater in the Ovsynch+CIDR group (67.7%, P<0.15) and was greater in the EB+CIDR+GnRH (73.2%, P<0.05) and CIDR-combined (both CIDR-treated groups were combined) groups (70.8%, P<0.05) than in the Ovsynch group (48.6%). Plasma progesterone concentrations were higher on Day 7 (P<0.01) and lower on Days 14, 17 and 21 (P<0.001) in the CIDR-combined group than in the Ovsynch group. Plasma estradiol-17beta concentrations were higher on Day 7 in the Ovsynch group of non-pregnant cows than in the CIDR-combined group of non-pregnant cows and in an all-combined group (all treatment groups combined) of pregnant cows (P<0.01). Furthermore, estradiol-17beta concentrations were lower on Day 9 in the Ovsynch and CIDR-combined groups of non-pregnant cows than in the all-combined group of pregnant cows (P<0.05). In conclusion, both protocols using CIDR improved conception rates following timed-AI in early postpartum suckled Japanese Black beef cows relative to the Ovsynch protocol. Treatment with a CIDR may prevent early maturation of follicles observed in non-pregnant cows treated with the Ovsynch protocol, by maintaining elevated blood progesterone concentrations until PGF(2 alpha) treatment.
Sakase
M
M
Department of Advanced Pathobiology, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan.
Seo
Y
Y
Fukushima
M
M
Noda
M
M
Takeda
K
K
Ueno
S
S
Inaba
T
T
Tamada
H
H
Sawada
T
T
Kawate
N
N
D000282:Administration, Intravaginal; D000818:Animals; D002417:Cattle / Q000502:physiology*; D003008:Cloprostenol / Q000008:administration & dosage; D003338:Corpus Luteum / Q000033:anatomy & histology; D015237:Dinoprost / Q000031:analogs & derivatives; D004958:Estradiol / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000097:blood; D005260:Female; D005306:Fertilization; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000031:analogs & derivatives; D007315:Insemination, Artificial / Q000379:methods / Q000662:veterinary*; D006080:Ovarian Follicle / Q000033:anatomy & histology; D010053:Ovary / Q000502:physiology*; D010062:Ovulation Induction / Q000379:methods / Q000662:veterinary; D049590:Postpartum Period; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D013997:Time Factors
C074283:estradiol 3-benzoate; D007987:Gonadotropin-Releasing Hormone; D003008:Cloprostenol; D011374:Progesterone; D004958:Estradiol; D015237:Dinoprost; C009936:fertirelin