# Buserelin: veterinary dose and monograph

> Buserelin is a veterinary drug. Synthetic GnRH analogue — releases LH/FSH to induce ovulation, treat follicular cysts, and improve fertility / conception. Indications include true anoestrus / sub-oestrus; ovarian (follicular) cyst — nymphomania; delayed ovulation / anovulation. This monograph lists 7 reference doses for cattle, horses, buffalo and ferrets, each with route, frequency and source, plus meat and milk withdrawal periods for food animals.

Source: https://vetmasterji.com/drugs/buserelin · Last reviewed: 2026-10-01

## At a glance

- **Drug class:** Veterinary drug
- **Also known as:** Receptal VET, Gynarich, Pregulate, Suprefact
- **Species with doses:** Cattle, Horses, Buffalo and Ferrets
- **Routes:** IM
- **Last reviewed:** 1 October 2026

## Indications

- True anoestrus / sub-oestrus
- Ovarian (follicular) cyst — nymphomania
- Delayed ovulation / anovulation
- Improvement of conception rate at AI
- Improvement of pregnancy rate 11–12 days post-AI
- Post-partum fertility (10–15 days post-calving)

## Buserelin dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

### Cattle

*Buserelin doses for cattle*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| True anoestrus / cystic ovaries | 20 µg per cow IM (5 mL of 4 µg/mL) | IM | once | — | no slaughter withdrawal / no milk discard |
| Conception improvement at AI | 10 µg per cow IM (2.5 mL) at insemination | IM | at insemination | — | Withdrawal NOT established — treat as extra-label |
| Delayed ovulation | 10 µg per cow IM at signs of oestrus | IM | once | — | Withdrawal NOT established — treat as extra-label |
| Pregnancy rate improvement (day 11–12 post-AI) | 10 µg per cow IM | IM | once | — | Withdrawal NOT established — treat as extra-label |

- True anoestrus / cystic ovaries: Label-sourced (Receptal / Gynarich, 4 µg/mL): 20 µg (5 mL) per cow IM for follicular cysts or true anoestrus. Buserelin has no monograph in Papich 5e or Plumb’s — gonadorelin is the referenced GnRH alternative. Follow the local label; GnRH analogues generally carry no withdrawal.
- Conception improvement at AI: Label-sourced (Receptal / Gynarich): 10 µg (2.5 mL) IM at insemination. Not in Papich 5e or Plumb’s.
- Delayed ovulation: Label-sourced (Receptal / Gynarich): 10 µg (2.5 mL) IM at signs of oestrus. Not in Papich 5e or Plumb’s.
- Pregnancy rate improvement (day 11–12 post-AI): Label-sourced (Receptal / Gynarich): 10 µg (2.5 mL) IM on days 11–12 after AI. Not in Papich 5e or Plumb’s.

### Horses

*Buserelin doses for horses*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Induction of ovulation | 20–40 µg per mare IM (5–10 mL) | IM | once | — |

- Induction of ovulation: Label-sourced (Receptal): 20–40 µg (5–10 mL) IM. Not in Papich 5e or Plumb’s (deslorelin or hCG are the referenced ovulation inducers).

### Buffalo

*Buserelin doses for buffalo*

| Indication | Dose | Route | Frequency | Duration | Withdrawal |
| --- | --- | --- | --- | --- | --- |
| Ovsynch / ovulation induction / follicular cysts | 10–20 µg per buffalo IM (2.5–5 mL) as the GnRH step | IM | per protocol | — | Withdrawal NOT established — treat as extra-label |

- Ovsynch / ovulation induction / follicular cysts: Receptal/Gynarich label buffalo with cattle: 10–20 µg (2.5–5 mL) IM as the GnRH component of Ovsynch (GnRH d0 → PGF2α d7 → GnRH d9 → AI). Widely used in buffalo fixed-time-AI programmes.

### Ferrets

*Buserelin doses for ferrets*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Suppression of oestrus (jill) | 1.5 µg per jill IM q24h for 2 days | IM | q24h × 2 days | — |

- Suppression of oestrus (jill): Carpenter's 6th ed (Ferret endocrine table): 1.5 µg per animal IM q24h for 2 days — GnRH analog used to suppress signs of oestrus / take an intact jill out of oestrus (an alternative to hCG).

## Contraindications

Hypersensitivity. Pregnancy (avoid until pregnancy confirmed by ultrasound). Do not use in animals with luteal cysts before luteolysis is confirmed.

## Species-specific warnings

> **Caution:** Cattle: Standard ovsynch component. 10 µg IM per cow. Zero withdrawal. Refrigerate to maintain potency.

> **Caution:** Horses: 20–40 µg IM for induction of ovulation in mares. Useful when hCG response inadequate.

> **Caution:** Goats: Used extra-label for follicular cysts at 5–10 µg IM single.

> **Caution:** Sheep: Used in synchronisation protocols at 5–10 µg IM.

## Adverse effects

- Generally well tolerated
- Rare hypersensitivity reactions

## Drug interactions

- Prostaglandin F2α (cloprostenol, dinoprost): SEQUENTIAL synergy in ovsynch protocol — GnRH day 0 → PGF2α day 7 → GnRH day 9 → AI day 10
- Progesterone (CIDR / PRID intravaginal devices): sequential synergy in PRID / CIDR-synch protocols
- Corticosteroids: theoretical inhibition of GnRH effect — limited clinical impact
- NSAIDs: no significant interaction at therapeutic doses

## Pregnancy and lactation

Generally safe in established pregnancy (after maternal recognition of pregnancy ~day 16). USED routinely on day 5–7 post-AI in cattle to improve conception (supplementary CL formation). Buserelin does NOT cause abortion (unlike PGF2α). Zero withdrawal periods make it convenient for dairy.

## Monitoring

- Oestrus detection at scheduled intervals — clinical response is the endpoint
- Pregnancy diagnosis at 28–42 days post-AI
- No serum monitoring needed — clinical effect is straightforward
- Zero withdrawal periods — convenient for all stages of dairy production
- Bovine follicular cysts: re-evaluate ovarian status by rectal palpation / ultrasound at 7–10 days

## Toxicity and overdose

Extremely safe — wide therapeutic margin. Acute high-dose: transient sweating, mild restlessness. NO known organ toxicity at clinical doses. Repeated daily dosing can cause pituitary GnRH receptor downregulation (clinically irrelevant at standard intervals).

Management: Supportive only — overdose extremely well tolerated. No specific antidote needed. Most overdoses asymptomatic.

## Clinical pearls

- OVSYNCH PROTOCOL (standard dairy reproductive management): GnRH (10 µg) day 0 → PGF2α day 7 → GnRH day 9 → timed AI day 10 — eliminates oestrus detection
- Bovine follicular cysts: 10 µg IM single — luteinises the cyst, resolves within 14–21 days
- Conception rate improvement at AI: 10 µg IM at insemination
- Day 5–7 post-AI: 10 µg IM forms supplementary CL — improves pregnancy rates 5–10%
- Equine: 20–40 µg IM at oestrus to induce ovulation — useful when mare doesn't respond to hCG
- ZERO milk / meat withdrawal — convenient for all stages of dairy production
- Refrigerate to maintain potency — peptide drug degrades at room temperature over weeks
- Use immediately after drawing into syringe — does not survive long in plastic

## Mechanism of action

Synthetic GnRH (gonadotrophin-releasing hormone) nonapeptide analogue — ~50× more potent than native GnRH and resistant to enzymatic degradation (longer half-life). Binds anterior pituitary GnRH receptors → stimulates LH (and FSH) release within 1–2 h. Peak LH at 2–4 h post-injection drives ovulation, luteinisation of unruptured follicles, and follicular cyst resolution. Standard ovsynch protocol component in dairy cattle.

## Formulations and products

- Receptal VET 0.004 mg/mL (MSD, 10 / 2.5 mL)
- Gynarich 4 µg/mL (Intas, 2.5 / 5 / 10 mL)
- Pregulate Buserelin Injection (Virbac)
- Receptal VET (MSD Animal Health) — 0.0042 mg/mL (≈4 µg/mL), Injection
- Gynarich (Intas (Neovet)) — 4 µg/mL, Injection
- Pregulate (Virbac) — Buserelin acetate, Injection
- Ovulanta (Mankind Veticura) — Buserelin acetate 4 µg/mL, Injection
- Sureshot-Lin (Assure Biotech, Jagadhri (HR)) — Buserelin acetate 4.2 mcg eq. buserelin 4 mcg per mL, Injection - supplied with syringe

## Storage

Injection: 2–8 °C (refrigerated) — most labels specify refrigerated. Multidose vial: 28 days after broaching (or per label). Protect from light. Do NOT freeze. May be stored at room temperature (15–25 °C) briefly during dispensing.

## Before you use this dose

> **Caution:** Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

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## Frequently asked questions

### What is the dose of Buserelin for cattle?

Reference doses for Buserelin in cattle: 20 µg per cow IM (5 mL of 4 µg/mL) IM once (True anoestrus / cystic ovaries); 10 µg per cow IM (2.5 mL) at insemination IM at insemination (Conception improvement at AI); 10 µg per cow IM at signs of oestrus IM once (Delayed ovulation); 10 µg per cow IM IM once (Pregnancy rate improvement (day 11–12 post-AI)). Confirm against the label and the patient before use.

### What is the dose of Buserelin for horses?

Reference doses for Buserelin in horses: 20–40 µg per mare IM (5–10 mL) IM once (Induction of ovulation). Confirm against the label and the patient before use.

### What is the dose of Buserelin for buffalo?

Reference doses for Buserelin in buffalo: 10–20 µg per buffalo IM (2.5–5 mL) as the GnRH step IM per protocol (Ovsynch / ovulation induction / follicular cysts). Confirm against the label and the patient before use.

### What is the withdrawal period for Buserelin?

Cattle, IM (True anoestrus / cystic ovaries): no slaughter withdrawal / no milk discard; Cattle, IM (Conception improvement at AI): Withdrawal NOT established — treat as extra-label; Cattle, IM (Delayed ovulation): Withdrawal NOT established — treat as extra-label; Cattle, IM (Pregnancy rate improvement (day 11–12 post-AI)): Withdrawal NOT established — treat as extra-label; Buffalo, IM (Ovsynch / ovulation induction / follicular cysts): Withdrawal NOT established — treat as extra-label. Follow the product label and national regulations where they differ.

### When should Buserelin not be used?

Hypersensitivity. Pregnancy (avoid until pregnancy confirmed by ultrasound). Do not use in animals with luteal cysts before luteolysis is confirmed.

### What are the side effects of Buserelin in animals?

Generally well tolerated; Rare hypersensitivity reactions.

## Sources

- MSD Animal Health catalogue · Receptal VET
- Intas Animal Health catalogue · Gynarich
- Plumb's Veterinary Drug Handbook
- Papich, Papich Handbook of Veterinary Drugs, 5th edition
- Carpenter, Exotic Animal Formulary

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VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.