Equine Chorionic Gonadotropin (eCG/PMSG)

Equine chorionic gonadotropin, historically called pregnant mare serum gonadotropin, is a glycoprotein hormone obtained from pregnant mares. It has FSH- and LH-like activity in non-equine species and is used to promote follicular development. Veterinary applications include anestrus treatment, reproductive synchronization and superovulation within species-specific fertility programs.

Group

Gonadotropin; FSH- and LH-like activity

Mechanism of Action

eCG binds gonadotropin receptors and provides sustained follicle-stimulating and luteinizing activity in responsive non-equine species. Receptor signaling promotes follicular growth, maturation and steroid production. Extensive glycosylation prolongs circulating activity, allowing continued follicular support after administration. The magnitude of the ovarian response determines whether the outcome is synchronized ovulation, increased ovulation rate or superovulation.

Dose Rates

Cattle

Use / stage	Dose	Route	Schedule	Instructions
Anoestrus	500–1000 IU/animal	IM	Once
Superovulation for embryo transfer	1500–3000 IU/animal	IM	Once	Give between days 8-13 of the cycle within the complete embryo-transfer protocol.
Fertility support after progestagen	300–750 IU/animal	IM	Once	At the end of progesterone/progestagen pretreatment; use the full selected reproductive protocol.

Buffaloes

Use / stage	Dose	Route	Schedule	Instructions
Anoestrus	500–1000 IU/animal	IM	Once

Indications

Induction and synchronization of follicular development or ovulation in cycling or anestrous cattle and small ruminants within supported reproductive protocols.
Superovulation of donor cows for embryo-transfer programs.
Selected increase of ovulation rate or litter size in sheep or goats with a corresponding protocol.
Induction of puberty or fertile estrus in selected gilts or sows, including supported eCG–hCG combination use.

Contraindications

Hypersensitivity; inappropriate use may cause excessive ovarian stimulation.

Interactions

Progestagen treatment and other reproductive hormones require protocol-specific timing.
Repeated exposure can reduce response through antibody formation.

Adverse effects

Excessive ovarian response, multiple ovulation and hypersensitivity are possible.

Toxicity

Avoid repeat dosing without ovarian reassessment; manage complications of excessive stimulation.

Preparations

Preparation	Form	Strength	Route
Folligon 1000 IU vial Vial content; supplied solvent volume must be checked before mL conversion.	Injection	1000 IU / vial	IM

Monitoring and Administration

Confirm ovarian status and cycle day before treatment. Superovulation doses are not anoestrus doses.

Folligon contains 1000 IU per vial, not 1000 IU per mL unless the final reconstituted volume establishes it. Refrigerate the cited product at 2-8°C.