There is continuing need to simplify bovine superovulation protocols without compromising embryo production. The control of follicular wave emergence and ovulation has facilitated donor management, but the most commonly used treatment, oestradiol, cannot be used in many parts of the world and mechanical removal of the dominant follicle is difficult to apply in the field. Other alternatives include gonadotrophin-releasing hormone (GnRH) or LH, but efficacy in groups of randomly cycling animals is variable. Another alternative is to increase the response to GnRH by inducing a persistent follicle and initiating FSH treatments following GnRH-induced ovulation. The number of transferable embryos following superovulation during the first follicular wave did not differ from that achieved 4 days after oestradiol benzoate and progesterone. To further simplify superovulation, FSH has been administered as a single intramuscular injection. Superovulation of beef donors with a single intramuscular injection of Folltropin-V (Bioniche Animal Health, Belleville, ON, Canada) diluted in a slow-release formulation resulted in embryo production comparable to that obtained using the traditional twice-daily protocol. The single intramuscular injection has the potential to reduce labour and handling and may be useful when handling stress is an impediment to success. These alternatives provide ways of facilitating widespread application of embryo transfer technologies.
Although we have previously shown that superstimulation during the first follicular wave resulted in a successful response (Carballo Guerrero D et al. 2007 Reprod. Fertil. Dev. 20, 226), the protocol required many interventions that could influence its application in the field. Therefore, two studies were designed to simplify the superstimulation treatment protocol. Experiment 1 was designed to determine whether it was necessary to remove the progesterone releasing device during the superstimulation protocol. Angus cows (n = 37) were superstimulated by two treatments in a crossover design. Cows in Group 1 (control) received a progesterone releasing device (Cue-Mate, Bioniche Animal Health, Belleville, ON, Canada) along with 0.150 mg D cloprostenol (PGF, Bioprost-D, Biotay, Argentina) IM, at random stages of the estrous cycle. Five days later, a second PGF was injected and Cue-Mates were removed, followed by GnRH (0.050 mg Lecirelina, Biosin-OV, Biotay) 36 h later; ovulation was expected to occur 30 to 36 h later. On Day 0 (36 h after GnRH) donors received a new Cue-Mate and superstimulation treatment was initiated with a total dose of 400 mg NIH-FSH-P1 of Folltropin-V (FSH, Bioniche Animal Health) in twice daily decreasing doses over 5 days. PGF was injected with the last two FSH injections and Cue-Mates were removed with the last FSH injection. Cows in Group 2 were treated similarly to those in the control group, except that Cue-mate devices were not replaced and remained in place for 13 days (i.e. Cue-mates were removed with the last FSH and PGF injection). All donors received 12.5 mg pLH (Lutropin-V, Bioniche Animal Health) 24 h after Cue-Mate removal and were AI 12 and 24 h later. Embryos were collected 7 days after pLH. Means were compared between groups by Student’s t-test. Superovulatory response and embryo production did not differ between groups. Mean (± SEM) number of ova/embryos collected and transferable embryos were 8.2 ± 1.0 and 4.1 ± 0.6 v. 9.8 ± 0.9 and 5.7 ± 0.7 for Groups 1 and 2, respectively (P > 0.2). Experiment 2 was designed to evaluate the effect of giving FSH for 4 v. 5 days. Simmental (n = 18) and Angus (n = 6) cows were superstimulated by the two treatment protocols in a crossover design. Cows in both groups were treated similarly to those in Group 2 in Experiment 1 (i.e. Cue-Mates were not replaced during treatment). Cows in Group 1 (control) received FSH over 5 days (as in Group 2 of Experiment 1); while those in Group 2 received the same dosage of FSH, but given in twice daily decreasing doses over 4 days (Cue-Mates were removed with the last FSH and PGF injections). Superovulatory response and embryo production did not differ among groups. Mean (± SEM) number of ova/embryos collected and transferable embryos were 13.5 ± 2.4 and 6.6 ± 1.1 v. 12.0 ± 1.9 and 5.8 ± 1.0 for Groups 1 and 2, respectively (P > 0.6). In conclusion, superstimulation of cattle at the time of emergence of the first follicular wave after ovulation results in an acceptable superovulatory response and all treatments evaluated were user-friendly and equally efficient.
Two experiments were designed to evaluate the superovulatory response of Brangus and Bonsmara donor cows to different dosages of Folltropin®-V (Bioniche Animal Health Inc., Belleville, Ontario, Canada) given by a single i.m. injection or twice-daily i.m. injections. In Experiment 1, Brangus cows (n = 12) were superstimulated by 6 treatments (2 × 3 factorial) in a crossover design (i.e. all cows received the 6 treatments and all treatments were represented on each day). On Day 0, cows received 5 mg of estradiol-17β plus 50 mg of progesterone and a Cue-Mate® (Bioniche Animal Health Inc.). On Day 4, cows were superstimulated with 300, 260, or 200 mg of NIH-FSH-P1 Folltropin®-V (Bioniche Animal Health Inc.) in twice-daily decreasing doses over 4 days or diluted in a slow release formulation (SRF; Bioniche Animal Health) and given in a single i.m. injection. The single injection was prepared by diluting the Folltropin®-V lyophilized powder in 1 mL of saline followed by mixing with 9 mL of the SRF in the syringe immediately before administration. In the am and pm of Day 6, all cows received PGF2, and Cue-Mates® were removed in the pm. Cows received 12.5 mg of porcine LH (Lutropin®-V; Bioniche Animal Health Inc.) in the am of Day 8 and were inseminated 12 and 24 h later. Ova/embryos were collected on Day 15 and data were analyzed by ANOVA. There was no effect of treatment (i.e. single v. twice-daily injections; P > 0.2) nor a treatment by dosage interaction (P < 0.6) on the mean (± SEM) number of total ova/embryos or transferable embryos (13.1 ± 1.9 and 7.5 ± 1.2 v. 15.5 ± 1.7 and 7.6 ± 1.0 for single v. twice-daily injections, respectively). The total number of ova/embryos did not differ among Folltropin®-V dosages (15.0 ± 2.3, 15.7 ± 2.0, and 12.1 ± 2.5 for 300, 260, and 200 mg, respectively; P > 0.4). However, the number of transferable embryos tended (P < 0.09) to be higher in donors receiving 260 mg (9.5 ± 1.6) than 200 mg (5.2 ± 0.8), with 300 mg (7.9 ± 1.5) intermediate. In Experiment 2, Bonsmara cows (n = 16) were superstimulated by 4 treatments (2 × 2 factorial) in a crossover design similarly to Experiment 1, except that 2 dosages of Folltropin®-V (200 and 300 mg) were evaluated. There were no significant effects of dosage of Folltropin®-V (P > 0.9), treatment (P > 0.3), or interaction (P < 0.4) on embryo production. The total number of ova/embryos and transferable embryos were 11.9 ± 2.0 and 7.2 ± 1.1 v. 11.1 ± 1.1 and 7.6 ± 0.7 for single and twice-daily injections, respectively, and 11.9 ± 1.9 and 7.6 ± 1.0 v. 11.1 ± 1.3 and 7.2 ± 0.8 for 300 and 200 mg of Folltropin®-V, respectively. Superstimulation of Brangus and Bonsmara cows with a single i.m. injection of Folltropin®-V diluted in a SRF resulted in comparable embryo production to twice-daily administration of Folltropin®-V over 4 days. While 260 mg seems to be the most appropriate dosage for Brangus donors, 200 mg seems to be adequate for Bonsmara donors.
Two experiments were designed to determine the superovulatory response of Angus donors treated with a single injection of Folltropin®-V diluted in a slow release formulation (SRF; Bioniche Animal Health Inc., Belleville, Ontario, Canada). Experiment 1 was designed to compare superovulatory response in Angus donor cows (n = 29 per group) treated with a single i.m. injection of Folltropin®-V diluted in SRF with cows treated using the traditional twice-daily i.m. injection treatment schedule. On Day 0, all cows received 5 mg of estradiol-17β plus 50 mg of progesterone and a Cue-Mate® (Bioniche Animal Health). On Day 4, cows were superstimulated with 400 mg of NIH-FSH-P1 Folltropin®-V in twice-daily decreasing doses over 4 days or in a single i.m. injection in the neck. The single injection was prepared by diluting the Folltropin®-V lyophilized powder in 1 mL of saline for injection and mixed with 9 mL of the SRF in the syringe immediately before administration. In the am and pm of Day 6, all cows received PGF2 and Cue-Mates® were removed in the pm. In the am of Day 8, cows received 12.5 mg of porcine LH (Lutropin®-V; Bioniche Animal Health) and were inseminated 12 and 24 h later. Ova/embryos were collected nonsurgically on Day 15 and evaluated following IETS recommendations. Means were compared between groups by t-test Mean (±SEM) number of ova/embryos and transferable embryos were 13.7 ± 2.1 and 7.1 ± 1.3 v. 12.3 ± 1.5 and 5.3 ± 0.8 for donors treated with the single v. twice-daily injections, respectively (P > 0.4). Experiment 2 was designed to confirm the results of Experiment 1 and to compare the effect of different dosages of Folltropin®-V on embryo production in Angus cows. Cows (n = 23) were superstimulated by 6 treatment protocols (2 × 3 factorial) in a crossover design (i.e. all cows received the 6 treatments and all treatments were represented on each collection day). Cows received the same treatments as cows in Experiment 1 except that the dosages of Folltropin®-V used were 200, 300, or 400 mg. Statistical analysis (ANOVA) revealed a significant effect of dosage of Folltropin®-V on embryo production, but there was no effect of treatment (i.e. single v. twice-daily injections; P > 0.2), nor was there a treatment by dosage interaction (P > 0.7). Mean (± SEM) number of ova/embryos and transferable embryos were 10.3 ± 0.9 and 5.4 ± 0.6 v. 11.3 ± 0.6 and 5.6 ± 0.5 for donors treated with the single or twice-daily injections, respectively (P > 0.2). Furthermore, the mean number of ova/embryos and transferable embryos were higher in cows treated with 400 mg (13.9 ± 1.1 and 6.5 ± 0.7) and 300 mg (12.0 ± 1.0 and 6.1 ± 0.7) of Folltropin®-V than those treated with 200 mg (6.6 ± 0.7 and 4.0 ± 0.5). In summary, superstimulation of Angus donor cows with a single i.m. injection of Folltropin®-V diluted in an SRF resulted in comparable embryo production to the traditional twice-daily i.m. administration of Folltropin®-V over 4 days. Although response did not differ between 300 and 400 mg, results suggest that 300 mg of Folltropin®-V given i.m. by a single or twice-daily injections is the most appropriate dose for Angus donor cows.
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