A single dose of FSH or hCG during a split-time AI program did not enhance follicular growth or pregnancy per artificial insemination in beef heifers

The objective of this study was to evaluate the effect a low dose hCG or FSH on follicle growth and pregnancy per artificial insemination (AI) in crossbreed beef heifers subjected split-time AI program. All (n = 386) were 7-d Co-synch protocol an intravaginal controlled internal drug release (CIDR) device (GnRH CIDR insertion; 7 days later PGF2α, removal, application tail head estrus detection patch; 36 hours detected estrus, 24 timed remaining heifers). At randomly assigned receive either 150 IU hCG, 20 mg FSH, remained as untreated controls. diameter preovulatory did not differ among treatments. A smaller (P 0.035) proportion group compared with control. Additionally, incidence premature ovulation greater < 0.01) treated In conclusion, using dosage at time removal affect pre-ovulatory pregnant heifers.