1.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.
Kawate N1, Sakase M, Seo Y, Fukushima M, Noda M, Takeda K, Ueno S, Inaba T, Kida K, Tamada H, Sawada T. J Reprod Dev. 2006 Feb;52(1):81-9. Epub 2005 Nov 17.
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.
2.Involvement of plasma progesterone, oestradiol-17beta and cortisol in ovulatory response to gonadotropin-releasing hormone in dairy cows with cystic follicles.
Isobe N1, Yamada K, Yoshimura Y. Reprod Domest Anim. 2007 Aug;42(4):370-5.
The aim of the present study was to examine the plasma concentrations of progesterone, oestradiol-17beta and cortisol in the cows with cystic follicle and to examine its relationship with the ovulatory response to gonadotropin-releasing hormone (GnRH). Eighty-five post-partum Holstein-Friesian cows with cystic follicles regardless of the presence of corpus luteum were studied. Follicular size, presence of corpus luteum and occurrence of ovulation were checked by palpation per rectum. Blood collection and palpation per rectum were conducted on days 0, 7 and 14. Gonadotropin-releasing hormone was administered at day 7. Plasma concentrations of progesterone, oestradiol-17beta and cortisol were determined. Progesterone concentrations of <3.2, 3.2-4.8 and >4.8 nmol/l were defined as low, intermediate and high, respectively. Sixty-three (74.1%) of 85 cows showed low (<3.2 nmol/l =1 ng/ml) progesterone concentrations on day 0. Only 40 (47.
3.Successful pregnancy following gonadotrophin-releasing hormone analogue treatment in a previously infertile bitch.
Tsumagari S1, Ishinazaka T, Watanabe G, Taya K, Ishii M. J Small Anim Pract. 2006 Apr;47(4):213-5.
A Labrador retriever bitch was presented with repeated unsuccessful breeding during both the third and fourth oestruses, even though accurate timing for natural mating was planned based on the results obtained using a semiquantitative luteinising hormone kit and a quantitative assay of progesterone. To identify the problem, serum luteinising hormone, follicle-stimulating hormone, progesterone, and oestradiol-17beta concentrations around the fourth oestrus stage were assayed by radioimmunoassay. Abnormal luteinising hormone fluctuations were detected during pro-oestrus and oestrus, and lower than normal progesterone concentrations were found during the mating period. In the fifth to seventh oestrus, the bitch was successfully treated with gonadotrophin-releasing hormone analogue at times based on the findings of the hormonal assays.
4.Basal levels and GnRH-induced responses of peripheral testosterone and estrogen in Holstein bulls with poor semen quality.
Devkota B1, Takahashi K, Matsuzaki S, Matsui M, Miyamoto A, Yamagishi N, Osawa T, Hashizume T, Izaike Y, Miyake Y. J Reprod Dev. 2011 Jun;57(3):373-8. Epub 2011 Feb 14.
The present study investigated the basal levels and GnRH-induced responses of peripheral testosterone and estrogen in Holstein bulls with poor semen quality. On the basis of semen parameters, bulls (n=5) having poor semen quality were selected as experimental bulls, and good semen quality bulls (n=4) were used as control bulls. Both groups were treated intramuscularly once with GnRH (250 µg of fertirelin acetate). Blood samples were collected at -1 day (d), -30 min and 0 h (treatment) followed by every 30 min for 5 h and 1, 3 and 5 d post-GnRH treatment (PGT), and LH, testosterone and estradiol-17β (E(2)) concentrations were measured. The pretreatment concentrations were used as basal levels. The percentage increments based on the 0-h levels were calculated per bull for each sampling time until 5 h PGT, and differences were compared between the experimental and control groups. The PGT concentrations of testosterone and basal and PGT concentrations of E(2) were significantly lower in the experimental group.
