162 FERTILITY OF BEEF RECIPIENTS FOLLOWING A FIXED-TIME EMBRYO TRANSFER PROTOCOL WHICH INCLUDED FOLLICLE STIMULATING HORMONE DILUTED IN HYALURONAN

Abstract

This study was performed to test the viability of administering Folltropin-V^® (FSH, Bioniche Animal Health) diluted in hyaluronan (MAP-5 50 mg, sodium hyaluronate, Bioniche Animal Health) to beef cows enrolled in a recipient synchronization protocol to evaluate its effect on recipient fertility. All recipients were administered an estradiol 17β (2.5 mg, IM) and progesterone (50 mg, IM) combination injection on Day 0, a CIDR^® (progesterone 1.34 g, Pfizer Animal Health, Groton, CT, USA) was inserted for 7 days. Lutalyse^® (dinoprost tromethamine, Pfizer Animal Health, 25 mg, IM) was administered at the time of CIDR removal on Day 7, and estradiol 17β (1 mg, IM) was administered on Day 8. On Day 16, the presence of at least one corpus luteum, detected via ultrasound, resulted in the recipient receiving an embryo (both fresh and frozen–thawed embryos were used). Embryos were not transferred into cows that did not show ultrasonic evidence of a CL. Dependent variables for which data were collected included circulating progesterone levels at the time of transfer and CL diameter, area, and circumference; measured in millimeters. The total study (n = 274) consisted of both wet (n = 85) and dry (n = 189) cows and included both Bos indicus (Brahman-influenced) crossbred (n = 93) and Bos taurus (Angus-based) cows (n = 181). The experiment consisted of cows being placed in either the treated or control groups, with treated cows receiving a single 40 mg (1 mL) IM injection of Folltropin-V in hyaluronan on Day 5 and control cows receiving no additional injections. Results are shown in Table 1. Transfer rate, conception rate, and pregnancy rate were tested for significance with chi-square analysis and remaining statistics were analyzed with a t-test: two-sample assuming equal variances. There were no significant differences found between the treated and control groups for transfer rate, conception rate, or pregnancy rate. Corpus luteum diameter was shown to be larger in control cows (P < 0.05); however, CL area and circumference did not differ significantly. Folltropin-V given with hyaluronan at a 40-mg dose on Day 5 did not improve fertility, induce a larger CL, or increase circulating progesterone levels in synchronized beef recipients as hypothesized. Further work is needed with Folltropin-V in hyaluronan to determine if an alternative dose or timing of administration would be more appropriate for improving fertility in recipients.

Table 1.  Fertility data in beef recipients following synchronization for fixed-time embryo transfer with a protocol that included (Treated) or did not include (Control) FSH in hyaluronan