POM-V Prescription Required

Prolusyn 50 micrograms/ml Solution for Injection for Cattle

Active ingredient: Gonadorelin

Form

Injection

Species

Cattle

Manufacturer

Syn Vet-Pharma Ireland Limited

VMD MA No.

54400/4000

What it's used for

Induction and synchronisation of oestrus and ovulation in combination with prostaglandin F2 (PGF2) or analogue with or without progesterone as part of Fi...

Full indications, dosage and side effects ↓

View official SPC (PDF)

The prescription itself has a price. See what practices near you charge for a consultation and the written prescription fee.

Paying less for Gonadorelin

1

Ask your vet for a written prescription

They must provide one on request. Under the CMA Order the fee is capped at £21 from 2027.
2

Fill it at a registered online retailer

The CMA found online pharmacies 50–60% cheaper than practice dispensing on common medicines — typically £200–£300 a year.

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Prescription required

Your vet must provide a written prescription on request. You can then purchase from any licensed online retailer.

Clinical information

Prolusyn 50 micrograms/ml Solution for Injection for Cattle — SPC Details

Source: VMD Summary of Product Characteristics (SPC). Last updated 26 Mar 2026.

Induction and synchronisation of oestrus and ovulation in combination with
prostaglandin F2 (PGF2) or analogue with or without progesterone as part of
Fixed Time Artificial Insemination (FTAI) protocols.
Treatment of delayed ovulation.

Intramuscular use.
100 μg
i.e. 2 ml of the product per animal.
Judgement on the protocol to be used should be made by the veterinarian
responsible for treatment, on the basis of the treatment objectives of the individual
herd or cow. The following protocols have been evaluated and could be used:
Induction and synchronisation of oestrus and ovulation in combination with a
prostaglandin F2 (PGF2) or analogue:
• Day 0: First injection of gonadorelin (2 ml of the product)
• Day 7: Injection of prostaglandin (PGF2) or analogue
• Day 9: Second injection of gonadorelin (2 ml of the product) should be done.
The animal should be inseminated within 16-20 hours after the last injection of the
product or at observed oestrus if sooner.
Induction and synchronisation of oestrus and ovulation in combination with a
prostaglandin F2 (PGF2) or analogue and a progesterone releasing
intravaginal device:
The following FTAI protocols have been commonly reported in the literature:
• Insert progesterone releasing intravaginal device for 7 days.
• Inject gonadorelin (2 ml of the product) at the progesterone device insertion.
• Inject a prostaglandin (PGF2) or analogue 24 hours prior to device removal
• FTAI 56 hours after removal of the device, or
• Inject gonadorelin (2 ml of the product) 36 hours after progesterone releasing
intravaginal device removal and FTAI 16 to 20 hours later.
Treatment of delayed ovulation:
GnRH is injected during oestrus.
To improve the pregnancy rates, the following timing of injection and insemination
should be followed:
- injection should be performed between 4 and 10 hours after oestrus detection
- an interval of at least 2 hours between the injection of GnRH and artificial
insemination is recommended
- artificial insemination should be carried out in accordance with the usual field
recommendations, i.e., 12 to 24 hours after oestrus detection.

Do not use in known cases of hypersensitivity to the active substance or to any of the
excipients.
Do not use during infectious diseases and other relevant health disorders.

Revised: March 2025
AN: 03514/2024 & 03814/2024

None known.

The response of dairy cows to synchronisation protocols may be influenced by the
physiological state at the time of treatment, which includes age of the cow, body
condition, health status and interval from calving.
Responses to treatment are not uniform either across herds or across cows within
herds.
Where a period of progesterone treatment is included in the protocol, the percentage
of cows displaying oestrus within a given period is usually greater than in untreated
cows and the subsequent luteal phase is of normal duration.

Special precautions for use in animals
Not applicable.
Special precautions to be taken by the person administering the veterinary medicinal
product to animals
Gonadorelin is a Gonadotropin Releasing Hormone (GnRH) analogue which
stimulates the release of sex hormones. The effects of accidental exposure to GnRH
analogues in pregnant women or in women with normal reproductive cycles are
unknown; therefore it is recommended that pregnant women should not administer
the product, and that women of child-bearing age should administer the product with
caution.
Care should be taken when handling the product to avoid self-injection. In case of
accidental self-injection, seek medical advice immediately and show the package
leaflet or the label to the physician.
Since GnRH analogues can be absorbed through the skin and benzyl alcohol may
cause mild local irritation, care should be taken to avoid skin and eyes contact. In
case of skin and/or eye contact, rinse immediately and thoroughly with plenty of
water.
GnRH analogues and benzyl alcohol may cause hypersensitivity (allergy). People
with known hypersensitivity to GnRH analogues or benzyl alcohol should avoid
contact with the veterinary medicinal product.

A synergistic effect is possible when used in combination with FSH. Simultaneous
use of human or equine chorionic gonadotropin can lead to ovarian overstimulation.

Keep vial in outer carton in order to protect from light.
Do not store above 25 °C.

Meat and offal: zero days
Milk: zero hours
5.

This information is sourced from the official Summary of Product Characteristics (SPC) published by the Veterinary Medicines Directorate (VMD). It is provided for informational purposes only and does not replace professional veterinary advice. Always consult your vet before administering any medication.