A Closer Look

Superovulation of Bos taurus beef cattle with two injections of Folltropin

John F. Hasler

Bioniche Animal Health, Inc.

Jfhasler05@msn.com

Due to the rapid absorption and short half-life of FSH, superovulation of cattle has traditionally been done with 7 or 8 bi-daily injections of FSH over a four day period. Restraining beef cattle for multiple injections involves time and expense. In addition, depending on breed and handling facilities, there are various degrees of stress to the cattle and increased risk of injury to both cattle and humans.

Trials conducted during the recent past involving Angus and Simmental cattle in Argentina demonstrated that when Folltropin was diluted in the glycosaminoglycan  hyaluronan, two injections of Folltropin 48 h apart resulted in superovulation and embryo production comparable to the traditional 8 injection protocol (Tribulo, et al., 2011, 2012). The diluent containing hyaluronan is now characterized as a slow release diluent (SRF). These studies were extended to field trials in the United States in the summers of 2010 and 2011.

The trials involved superovulation of Bos taurus beef cattle in 6 commercial embryo transfer (ET) programs either on farm or housed in embryo transfer facilities. Half of the donors (controls) were superovulated with 8 injections of Folltropin-V (Bioniche Animal Health, Inc.), while the other half were injected twice with Folltropin-V reconstituted in a slow release formulation (SRF) diluent containing 0.5% hyaluronan (Map 5, Bioniche). The study was divided into two phases: 1) In 2010, cows were each superovulated once by 6 ET practitioners in either a control (n=63) or treatment group (n=57); 2)  In 2011, cows (n=46) were each superovulated twice in a cross-over design by three ET practitioners.

Animals were synchronized prior to the start of FSH injections by one of 4 protocols: 1) FSH was started between days 8 and 13 of the cycle; 2) Use of a CIDR and GnRH with FSH started two days later; 3) Use of a CIDR and estradiol 17B with FSH started 4 days later; or 4) Insertion of a CIDR with FSH started 4 days later. Control females received 8 injections of descending doses of FSH totaling 260 to 400 mg. On the day that FSH injections were initiated (Day 0) for all four synchronization protocols, controls received the first of 8 twice-daily FSH descending doses of FSH, while donors in the treatment group received a dose of FSH in SRF diluent totaling 67% of the total amount of FSH given to control donors. Treatment donors received the remaining 33% of SRF FSH 48 h later, on day 2. Both treatment and control donors received two injections of PG on day 2 or 3 and CIDRs were pulled on day 3. All animals were inseminated with one or two straws of semen at 12 and 24 hours following onset of standing estrus. Donors were flushed 7 days after onset of estrus and all ova/embryos counted and graded for stage and quality.

There was no effect of year on any category of ova/embryos recovered nor was there any treatment by year interaction. The least squares means of ova/embryos for both years combined are presented in Table 1.

Table 1. Least squares means of ova/embryos recovered from control versus treated donors in years 1 and 2 combined.

There were no significant differences (ANOVA) in the number of ova, transferable embryos, unfertilized ova or degenerate embryos recovered from the control versus the SRF groups. The trials conducted in the United States demonstrated that Bos taurus beef cattle can be successfully superovulated with only two injections of FSH reconstituted in an SRF diluent and involving a variety of synchronization protocols. The SRF diluent is available from Bionich Animal Health, Inc.

References:

Tribulo, Andres, et al. 2011. Superstimulation of ovarian follicular development in beef cattle with a single intramuscular injection of Folltropin-V. Anim. Reprod. Sci. 129:7-13.

Tribulo, Andres, et al. 2012. Superovulation of beef cattle with a split-single intramuscular administration of Folltropin-V in two concentrations of hyaluronan. Theriogenology 77:1679-1685.

Hasler, John F. and Hockley, Duncan 2012. Efficacy of hyaluronan as a diluent for a two injection FSH superovulation protocol in Bos taurus beef cows. ICAR, In Press.