Tag Archives: Altrenogest

Altrenogest (Regu-Mate, Matrix)

Oral Progestin Highlights Of Prescribing Information • Progestational drug used in horses to suppress estrus or maintain pregnancy when progestin deficient; used in swine to synchronize estrus • May be used in dogs for luteal deficiency or as a treatment to prevent premature delivery • Many “handling” warnings for humans (see below) • Very sensitive… Read More »

Stallion Behavior Problems

This post briefly outlines several of the most common behavior problems of breeding stallions. These problems include self-mutilation, inadequate libido, rowdy breeding behavior, specific erection dysfunction, mounting and thrusting difficulties, frenzied hyperactive behavior, and specific ejaculation dysfunction. Also briefly outlined is the common problem of residual stallionlike behavior in geldings. Inadequate Libido Specific stallion libido… Read More »

Placental Hydrops

Hydrops is a rare condition in the mare, with hydroallantois occurring more commonly than hydramnios. Hydroallantois causes rapid abdominal enlargement during the last trimester of pregnancy (), and a sudden increase in the volume of allantoic fluid during a period of 10 to 14 days. The pathophysiology of hydroallantois in the mare remains unknown. Some… Read More »


The equine placenta consists of the allantochorion, the allantoamnion, and the umbilical cord. The chorionic portion of the allantochorion is attached to the endometrium by microcotyledons that are present throughout the uterus, with the exception of a small area at the internal os of the cervix called the cervical star. The allantochorion supports the fetus… Read More »

Foal Heat-Breeding

Commercial horse breeding farms operate under the same economic rules as other forms of intensive livestock production. Use of stallions must be efficient, and mares must produce the greatest number of foals possible. This requires intensive management. The primary reason for foal heat-breeding is to increase the efficiency of the production unit. The performance of… Read More »


The diffuse microcotyledonary placentation of the mare makes it highly unlikely that a twin pregnancy will be carried to term. If the twin pregnancy is maintained until the latter part of gestation the placenta cannot meet the nutrient demands of the rapidly growing fetuses. Death of one or both fetuses is followed by abortion, with… Read More »

Endometrial Cysts

Endometrial cysts are often cited as a cause of infertility; however, a cause-and-effect relationship has not been clearly established. The proportion of mares with endometrial cysts increases with age. Mares over 11 years of age are more than four times as likely to have endometrial cysts as younger mares and a majority of mares over… Read More »

Cutaneous Lymphosarcoma

Clinical manifestations of lymphosarcoma in horses include cutaneous, multicentric, thymic, and alimentary forms. Cutaneous lymphosarcoma can exist as a primary disease entity limited to skin and subcutaneous tissues or concurrently with visceral involvement. Horses of all ages have been diagnosed with lymphosarcoma, with the majority being between the ages of 4 and 9 years. No… Read More »

Treatment of Cutaneous Lymphosarcoma

Glucocorticoids remain the mainstay of treatment of cutaneous T cell-rich, B cell lymphoma. Tumor regression is typically noted following the systemic administration of dexamethasone (0.02-0.2 mg/kg IV, IM or PO q24h) or prednisolone (1-2 mg/kg PO q24h). In these authors’ experience, dexamethasone proves more effective than prednisolone in treating lymphosarcoma. Once cutaneous lesions have regressed… Read More »