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Nasser L.F.,Born Animal Biotechnology Panama Corporation | Rezende C.R.,Firmasa Tecnologia para pecuaria LTDA | Mapletoft R.J.,University of Saskatchewan | Bo G.A.,Institute Reproduccion Animal Cordoba
Theriogenology | Year: 2011

Three experiments were conducted to evaluate the effects of exogenous progesterone on superovulatory response and ova/embryo quality in Bos indicus donors superstimulated during the first follicular wave (FFW). We hypothesized that exogenous progesterone during gonadotropin treatments would improve ova and embryo quality. In Experiment 1, 18 Nelore cows were randomly allocated to three groups: (1) FFW; (2) FFW plus a progesterone-releasing device (FFW+P4); and (3) control (E2+P4). Cows in the FFW groups were superstimulated beginning at synchronized ovulation, whereas cows in the control group were superstimulated after synchronization of follicular wave emergence with estradiol plus progesterone (E2+P4). There were no differences in mean (± SD) numbers of transferable embryos between FFW+P4 (8.0 ± 4.5) and control (6.7 ± 4.8) groups, but both were higher (P = 0.006) than the FFW group (0.2 ± 0.4). In Experiment 2, FFW and FFW+P4 were compared in 20 Nelore donors; exogenous progesterone increased the number of transferable embryos (3.9 ± 3.4 vs. 1.3 ± 4.1, P = 0.003). In Experiment 3, FFW and FFW+P4 were compared in 10 Nelore donors except that cows were slaughtered 12 h after pLH (Lutropin-V ®, Bioniche Animal Health, Belleville, ON, Canada) treatment. More mature cumulus oocyte complex (COC) (expanded cumulus cell layers) were collected in the FFW+P4 group than in the FFW group (21.8 ± 13.1 vs. 10.8±14.7; P = 0.003). In summary, superovulatory response was satisfactory when FSH (Folltropin-V ®, Bioniche Animal Health) treatment was initiated at emergence of the first follicular wave in Nelore (Bos indicus) donors, and the hypothesis that administration of exogenous progesterone during the treatment will improve oocyte and embryo quality was supported. © 2011 Elsevier Inc. Source

Butler S.A.A.,University of Queensland | Phillips N.J.,University of Queensland | Boe-Hansen G.B.,University of Queensland | Bo G.A.,Institute Reproduccion Animal Cordoba | And 3 more authors.
Reproduction in Domestic Animals | Year: 2012

The primary objective of this study was to investigate the impact of animal-level factors including energy balance and environmental/management stress, on the ovarian function of Bos indicus heifers treated to synchronize ovulation. Two-year-old Brahman (BN) (n=30) and BN-cross (n=34) heifers were randomly allocated to three intravaginal progesterone-releasing device (IPRD) treatment groups: (i) standard-dose IPRD [Cue-Mate ® (CM) 1.56g; n=17]; (ii) half-dose IPRD [0.78g progesterone (P 4); CM 0.78g; n=15]; (iii) half-dose IPRD+300IU equine chorionic gonadotrophin at IPRD removal (CM 0.78g+G; n=14); (iv) and a control group, 2× PGF 2α [500μg prostaglandin F 2α (PGF 2α)] on Day -16 and -2 (n=18). Intravaginal progesterone-releasing device-treated heifers received 250μg PGF 2α at IPRD insertion (Day -10) and IPRD removal (Day -2) and 1mg oestradiol benzoate on Day -10 and -1. Heifers were managed in a small feedlot and fed a defined ration. Ovarian function was evaluated by ultrasonography and plasma P 4 throughout the synchronized and return cycles. Energy balance was evaluated using plasma insulin-like growth factor 1 (IGF-I) and glucose concentrations. The impact of environmental stressors was evaluated using plasma cortisol concentration. Heifers that had normal ovarian function had significantly higher IGF-I concentrations at commencement of the experiment (p=0.008) and significantly higher plasma glucose concentrations at Day -2 (p=0.040) and Day 4 (p=0.043), than heifers with abnormal ovarian function. There was no difference between the mean pre-ovulatory cortisol concentrations of heifers that ovulated or did not ovulate. However, heifers that ovulated had higher cortisol concentrations at Day 4 (p=0.056) and 6 (p=0.026) after ovulation than heifers that did not ovulate. © 2011 Blackwell Verlag GmbH. Source

Phillips N.J.,University of Queensland | Fordyce G.,Australian Department of Primary Industries and Fisheries | Burns B.,Australian Department of Primary Industries and Fisheries | Williams P.,CSIRO | And 3 more authors.
Reproduction in Domestic Animals | Year: 2010

Contents: The study tested the hypothesis that reduced intravaginal implant progesterone (P4) concentration to synchronise oestrus would increase pregnancy rates to fixed-time artificial insemination (FTAI) in Bos indicus heifers. Brahman heifers (n = 294; 2 year) were body condition scored (BCS), weighed and scanned for presence of a corpus luteum (CL). Only cyclic heifers were selected and allocated randomly within BCS and 25 kg bodyweight category to one of three P4 treatment groups. On day 10, heifers received a P4 implant (CueMate-1-pod, 0.78g P4; CueMate-2-pod, 1.56g P4; or CIDR-B, 1.9g P4), 2 mg oestradiol benzoate (ODB) intramuscularly (IM) and 250 ug cloprostenol IM. At day 2, the implant was removed, 250 ug cloprostenol was injected IM and tail paint applied. The heifers received 1 mg ODB 24 h later and were FTAI 48-54 h after implant removal (day 0). Ten randomly selected heifers per group were blood sampled and scanned at days 10, 2, 0 and 6 to define the P4 profiles pre- and post-FTAI. Heifers were heat-detected 18-20 days post-FTAI and oestrous heifers AI'd by the AM/PM rule. Bulls joined the heifers on day 27 post-FTAI. Transrectal ultrasonography estimated conception date on day 72. Statistical analysis examined the effects of treatment, technician, semen, ovarian status, BCS and liveweight, on pregnancy rate (PR) to FTAI. There was no significant difference (p = 0.362) in PR between treatment groups (CueMate 1-pod, 36.4%; CueMate 2-pod, 39.6%: CIDR-B, 28.3%), but PR was higher in those heifers with increased BCS between FTAI and pregnancy diagnosis (p = 0.005). Thirty-three per cent of monitor heifers had plasma P4 concentrations of <1 ng/ml on day 6 after FTAI; only 20% of these conceived vs 60% of heifers with P4 ≥ 1 ng/ml. In summary, no significant difference in PR was identified between treatments but good BCS and a rising plane of nutrition were critical to PR of these pure grade Brahman heifers in northern Australia. © 2010 Blackwell Verlag GmbH. Source

Garcia Guerra A.,University of Saskatchewan | Garcia Guerra A.,University of Wisconsin - Madison | Tribulo A.,Institute Reproduccion Animal Cordoba | Yapura J.,University of Saskatchewan | And 4 more authors.
Theriogenology | Year: 2015

A study was designed to compare the effects of a conventional (4 days) versus a lengthened (7days) superstimulation protocol on follicle dynamics and to test the hypothesis that superstimulatory treatment only rescues small follicles within the wave. Nonlactating beef cows received a progesterone-releasing intravaginal device [PRID] and were superstimulated with 400-mg FSH on the day of follicle ablation-induced wave emergence (Day 0). The control group (n=5) received FSH over 4days, whereas the long group (n=5) received FSH over 7days. PGF was administered twice on Day 2 (control group) or 5 (long group), and PRIDs were removed 24hours after the first PGF. Cows received 25-mg LH 24hours after PRID removal. The cows chosen for the present study represented a subset from a larger group of 24 cows in which superovulationresults were obtained and published. Cows in the present study were those with the lowest antral follicle counts at the time of wave emergence in order to facilitate tracking of individual follicles. Daily ultrasonographic examinations monitored follicle diameters and numbers. A reduction (P<0.01) in the number of 1- to 2-mm follicles from Day 0 to the end of the superstimulatory treatment was associated with a progressive shift to the next size category in both groups. On the day of LH treatment, the number of follicles in any size category did not differ between groups. The number of follicles of diameter 5mm or less decreased during superstimulation (i.e., no continuous recruitment of small follicles; P<0.001), and the number of follicles of diameter 1mm or greater at the end of superstimulation did not differ from that at the beginning of superstimulation (P=0.739). However, the total number of follicles of diameter 3mm or greater at the end was greater than the number of follicles of diameter 3mm or greater at the beginning of superstimulation because of growth of the 1- to 2-mm population during treatment (P<0.001). Follicle growth was slower in the long group than in the control group. Results support the hypothesis that both 4-day and 7-day superstimulatory protocols rescue small antral follicles present at the time of wave emergence; there was no evidence for continuous recruitment of new follicles. Results also provide rationale for the hypothesis that a lengthened treatment protocol is associated with greater follicle maturation and capacity to ovulate. © 2015 Elsevier Inc. Source

Garcia Guerra A.,University of Saskatchewan | Tribulo A.,Institute Reproduccion Animal Cordoba | Yapura J.,University of Saskatchewan | Singh J.,University of Saskatchewan | Mapletoft R.J.,University of Saskatchewan
Theriogenology | Year: 2012

This study determined if lengthening the superstimulation protocol from 4 to 7 days would result in an increase in the superovulatory response with no adverse effects on oocyte/embryo competence in beef cows. Follicular ablation was performed, a progesterone-releasing intravaginal device (PRID) was inserted, and cows were assigned to one of two treatment groups 5 to 8 days after ovulation: Control (4 days of follicle stimulating hormone (FSH)) or Long (7 days of FSH; n = 12 per group). The FSH treatments were initiated 1.5 days later (Day 0). A dose of 400 mg NIH-FSH-P1 (Folltropin-V) was distributed equally over 8 (Control) or 14 (Long) im injections at 12-h intervals. Prostaglandin F2α (PGF) was administered twice, 12 h apart, on Day 2 (Control) or Day 5 (Long), and PRID were removed 12 h after the second PGF. Both groups were given 25 mg pLH (lutropin-V) im 24 h after PRID removal and AI was done 12 and 24 h later. Ova/embryos were collected 7 days after the pLH injection. The mean (± SEM) number of ≥ 9 mm follicles at the time of first AI did not differ (P = 0.24) between groups, but more ovulations (30.9 ± 3.9 vs. 18.3 ± 2.9, P = 0.01) and CL (27.2 ± 2.1 vs. 20.8 ± 2.2, P = 0.04) occurred in the Long group. A higher proportion of the ≥ 9 mm follicles ovulated between 12 and 36 h after pLH in the Long group (93 vs. 69%; P = 0.001). Although numerically higher in the Long group, mean numbers of total ova/embryos, fertilized ova, transferable or freezable embryos did not differ. In conclusion, a lengthened superstimulatory treatment protocol resulted in more follicles acquiring the capacity to ovulate with an increased number of ovulations, and without a decrease in oocyte/embryo competence. © 2012 Elsevier Inc. Source

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