Superovulation and embryo quality in beef cows using PMSG and a monoclonal anti-PMSG

Area of Science:

• Veterinary Medicine
• Reproductive Biology
• Animal Science

Background:

• Pregnant mare serum gonadotrophin (PMSG) has a long half-life, limiting its use in cattle superovulation.
• Monoclonal antibodies can be used to neutralize hormones, potentially improving reproductive treatments.

Purpose of the Study:

• To investigate the effect of administering anti-PMSG alongside varying dosages of PMSG on superovulation outcomes in cattle.
• To determine if anti-PMSG can mitigate the negative effects of high PMSG dosages and improve transferable embryo yield.

Main Methods:

• 149 beef cows received 1500, 3000, or 6000 IU of PMSG with or without anti-PMSG.
• Estrus, ovulation, ovarian follicle counts, corpora lutea (CL) counts, and embryo recovery were assessed.
• Cows were ovariectomized on Day 9 post-estrus for detailed ovarian analysis.

Main Results:

• Estrus and ovulation rates decreased significantly with increasing PMSG dosage.
• Anti-PMSG reduced corpora lutea weight but increased small ovarian follicles and decreased large follicles.
• While total embryo numbers did not differ, the percentage of transferable embryos decreased with higher PMSG dosages.

Conclusions:

• Administering anti-PMSG did not enhance the number of transferable embryos in cattle superovulation.
• High PMSG dosages negatively impact estrus and ovulation rates, and anti-PMSG alters follicular dynamics without improving embryo yield.