Progesterone is a steroid hormone produced by the mare in pregnancy (by the ovary in early pregnancy, and by the fetus and placenta in later pregnancy). It is required for pregnancy. Progesterone has an inhibitory effect on the estrus cycle in mares and reduces estrus behavior.
Altrenogest (Regu-Mate®, Altresyn®) is a liquid, synthetic oral progestin that is used to suppress estrus in mares. It is used to facilitate scheduled breeding, to maintain pregnancy, and to suppress undesirable behaviors (“hormonal distractions”) resulting from estrus. Altrenogest has a direct effect on the uterine muscle, causing a variety of effects typical of progesterone, the natural hormone of pregnancy in the mare.
Talk to your vet about whether this treatment is appropriate for your horse. It is fed daily to mares in their feed, or orally dosed daily per your vet’s recommendations.
Antrenogest is contained in a very oily, absorptive base and requires the use of gloves when handling. It should not be handled by pregnant women, or women who believe they may be pregnant.
This Treatment Might be used for a horse exhibiting these signsRelated Observations
Related DiagnosesThis Treatment Might Be Used for these Diagnoses
Consider Potential Side Effects & Complications
Altrenogest can perpetuate a uterine infection. It can also cause the cervix to close, which may decrease uterine defenses.
Consider Reasons Not To Use This Treatment
Not used in mares with a uterine infection because it may worsen it. It should not be handled by pregnant women, or women who believe they may be pregnant.
Skills I might need
Is It working? Timeframe for effect
Within a day or two of administration, you may notice behavioral changes in your mare. The actual effects on the uterus probably take place within hours.
Questions To Ask My Vet
- What precautions do I need to take in handling altrenogest?
Helpful Outside ResourcesCredible Equine Health Information on the Internet
Horse Side Vet Guide? Contact us to start the conversation.