Browsing by Author "Cunha, Arcelina Pacheco"

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Comparison of gonadorelin products in lactating dairy cows: Efficacy based on induction of ovulation of an accessory follicle and circulating luteinizing hormone profiles
(Elsevier Science, 2009-07-15) Souza, Alex H.; Cunha, Arcelina Pacheco; Silva, Eder Pereira; Ayres, Henderson; Guenther, Jerry N.; Wiltbank, Milo C.; Gümen, Ahmet; Uludağ Üniversitesi/Veteriner Fakültesi/Kadın Hastalıkları ve Doğum Anabilim Dalı.; AAH-1406-2021; 6602393069
This study evaluated whether the four gonadorelin products that are commercially available in the United States produce comparable ovulation responses in lactating cows. Dairy cows at 7 d after last gonadotropin-releasing hormone (GnRH) treatment of Ovsynch (Day 7), with a corpus luteum (CL) >= 15 mm and at least one follicle >= 10 mm, were evaluated for response to GnRH treatment. Selected cows were randomized to receive (100 mu g; im): (1) Cystorelin (n = 146): (2) Factrel (n = 132): (3) Fertagyl (n = 140); or (4) Ovacyst (n = 140). On Day 14, cows were examined for Ovulation by detection of an accessory CL. Circulating luteinizing hormone (LH) concentrations were also evaluated in some cows after treatment with 100 mu g (n = 10 per group) or 50 mu g (n = 5 per group) GnRH. Statistical analyses were performed with the procedures MIXED and GLIMMIX of the SAS program. Percentage of cows ovulating differed (P < 0.01) among groups, with that for Factrel being lower (55.3%) than that for Cystorelin (76.7%), Fertagyl (73.6%), or Ovacyst (85.0%), There was no effect of batch, parity, or follicle size on ovulation response. but increasing body condition score decreased Ovulation response. There was a much greater LH release in cows treated with 100 mu g than in those treated with 50 mu g, but there were no detectable differences among products in time to LH peak, peak LH concentration, or area under the LH curve and no treatment effects nor treatment by time interactions on circulating LH profile. Thus, ovulation response to Factrel on Day 7 of the cycle was lower than that for other commercial GnRH products, although a definitive mechanism for this difference between products was not demonstrated.
Supplementation with estradiol-17 beta before the last gonadotropin-releasing hormone injection of the ovsynch protocol in lactating dairy cows
(Elsevier Science, 2007-10) Souza, Alexandre H.; Silva, E.; Cunha, Arcelina Pacheco; Guenther, J. N.; Peto, C. M.; Caraviello, D. Z.; Wiltbank, Milo C.; Gümen, Ahmet; Uludağ Üniversitesi/Veteriner Fakültesi/Doğum ve Jinekoloji Anabilim Dalı.; 6602393069
The aim of this study was to determine whether an increase in circulating estrogen concentrations would increase percentage pregnant per artificial insemination (PP/AI) in a timed AI protocol in high-producing lactating dairy cows. We analyzed only cows having a synchronized ovulation to the last GnRH of the Ovsynch protocol (867/1,084). The control group (n = 420) received Ovsynch (GnRH - 7 d - PGF2α - 56 h - GnRH -16 h - timed AI). The treatment group (n = 447) had the same timed AI protocol with the addition of 1 mg of estradiol-17β (E2) at 8 h before the second GnRH injection. Ovarian ultrasound and blood samples were taken just before E2 treatment of both groups. In a subset of cows (n = 563), pressure-activated estrus detection devices were used to assess expression of estrus at 48 to 72 h after PGF2α treatment. Ovulation was confirmed by ultrasound 7 d after timed AI. Treatment with E2 increased expression of estrus but overall PP/ AI did not differ between E2 and control cows. There was an interaction between treatment and expression of estrus such that PP/AI was greater in E2-treated cows that showed estrus than in E2-treated or control cows that did not show estrus and tended to be greater than control cows that showed estrus. There was evidence for a treatment by ovulatory follicle size interaction on PP/AI. Supplementation with E2 improved PP/ AI in cows ovulating medium (15 to 19 mm) but not smaller or larger follicles. The E2 treatment also tended to improve PP/AI in primiparous cows with low (S2.5) body condition score, and in cows at first postpartum service compared with Ovsynch alone. In conclusion, any improvements in PP/AI because of E2 treatment during a timed AI protocol appear to depend on expres sion of estrus, parity, body condition score, and size of ovulatory follicle.
Ultrasonographic evaluation of endometrial thickness near timed AI as a predictor of fertility in high-producing dairy cows
(Elsevier, 2011-03-01) Souza, Alexandre H; Silva, Eduardo P.B.; Cunha, Arcelina Pacheco; Ayres, Henderson; Brusveen, D. J.; Guenther, Jerry N.; Wiltbank, Milo Charles; Gümen, Ahmet; Uludağ Üniversitesi/Veterinerlik Fakültesi/Veteriner Doğum ve Jinekoloji Anabilim Dalı.; AAH-1406-2021; 6602393069
The objectives were to evaluate changes in endometrial thickness (ET) near the time of a synchronized ovulation and to assess the relationship of ET and fertility in lactating Holstein cows, with or without estrogen supplementation near timed ovulation. In Experiment 1, eight cows were examined with transrectal ultrasonography, once daily for 5 d, starting concurrent with PGF(2 alpha) (PGF) treatment during an Ovsynch protocol (GnRH - 7d - PGF - 72h - GnRH). The ET increased rapidly after PGF (from similar to 7 to similar to 9.5 mm), remained > 9 mm for the next 2 d, then decreased to similar to 8 and 7.4 mm, 1 and 2 d, respectively, after the second GnRH. In Experiment 2,642 cows (total of 758 breedings) were subjected to an Ovsynch protocol (GnRH - 7d - PGF - 56h - GnRH - 16h - timed AI); cows received either no further treatment (Ovsynch) or 1 mg of estradiol-17 beta im 8 h before the second GnRH (Ovsynch + E2). For both uterine horns, ET was measured (similar to 2 cm from the internal uterine body bifurcation) before E2 treatment (48 h after PGF). In cows with ET <= 8 mm vs > 8 mm, rates of ovulation were 86.0% (n = 136) vs 98.1% (n = 472; P < 0.01), respectively, and percentage pregnant per AT (P/AI) were 26.7% (n = 146) vs 42.7% (n = 524; P < 0.01). Treatment with E2 increased P/AI in cows with lower ET (Ovsynch + E2 = 37.0% vs Ovsynch = 23.3%; P = 0.07), but did not significantly improve P/AI in cows with ET > 8 mm (Ovsynch + E2 = 43.4% vs Ovsynch = 42.1%). In conclusion, a single ultrasonographic evaluation of ET in Holstein cows 48 h after PGF treatment in an Ovsynch program was a good predictor of ovulation failure and pregnancy success. Perhaps poor fertility in cows with reduced ET was low peripheral E2 concentrations near AI, poor P4 priming, or luteolysis failure during timed AI procedures.