Management for Early Breeding - Progesterone
It is possible to initiate growth of follicles, estrus and ovulation by giving progesterone for 10 - 14 days and then withholding the progesterone (do not give). The choices for this treatment are:
- Regumate (Altrenogest; oral progestin placed in feed or directly in the mouth, 10 to 12 cc/day, main choice)
- Progesterone (intramuscular injection, 150 mg/day, not used much)
The problem with progesterone is that like GnRH, mare's must already have follicles present (at least a 20 mm follicle)and be in the late transition period to be effective. Both GnRH and Progesterone treatment work best if the mare is first evaluated with palpation or ultrasound to determine follicles are present before initiating treatment.
