Joint Advisory to Trainers - Notice to cease using Altrenogest Injections in Race horses:

posted Sep 26, 2018, 8:21 PM by Karin Attwood   [ updated Sep 26, 2018, 8:23 PM ]
New Zealand veterinarians have been advised by the Equine Branch of NZ Veterinary Assn to cease using all injectable forms of Altrenogest in race horses forthwith. 
This decision has been made because the anabolic steroids Trenbolone and Trienolone have been detected in post-race urine samples in Australia from the use of Altrenogest injections. Trenbolone and Trienolone are impurities found in very low concentrations following the manufacture of the Altrenogest raw material. 

Altrenoget is exempt under the Prohibited Substances Regulations when used in females. Altrenogest is a powerful progestin of the 19-nortesterone group with the chemical name of Allytrenbolone. 

However, both Trenbolone and Trienolone are anabolic steroids and prohibited substances under both HRNZ and NZTR Prohibited Substances Regulations. 

The use of Altrenogest in the oral form has been extensively used for decades and was first licenced by the ACVM in 1982. To date there has never been any Trenbolone or Trienolone detected in post- race urine samples when using oral Altrenogest and a possible reason could be Trenbolone and Trienolone are poorly absorbed by the oral route. 

Two injection formulations were licenced by ACVM in November 2017. 

Recommendations from the Equine Branch of NZ Veterinary Assn to Equine Vets: 
1. Cease using Altrenogest Injections in racing females. 
2. When using oral Altrenogest in racing females use the listed label dose rate. Do not double dose. 
3. Stop using oral Altrenogest in racing females “one clear day” from racing. 

Basis on NZTR position on the administration of Altrenogest 
Whilst the injectable form must not be used in race horses for the reasons outlined above, the continued use of oral Altrenogest is acceptable for the following reasons: 
1. Health and Safety. There is a risk that people may be get injured either by colts becoming frisky besides mares in season or mares in season kicking out and hitting stable staff. 
2. Mares in season can produce and unreliable form. 
3. Keeping race numbers up. Mares in season often don’t make it to the races. 

Dr. Andrew Grierson- NZTR Chief Veterinarian 

Martin Burns- GM Racing and Equine Welfare NZTR

Edward Rennell - CEO Harness Racing NZ