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10th August 2006

Foetal Sex Determination Tests

A relatively new veterinary procedure is gaining wide acceptance in the world-wide thoroughbred stud industry.

Scone veterinary surgeon Kevin Doyle is one of only a handful of vets who have specialized in this area of testing your mare to determine the foetal sex of the foal she is carrying. In the past very few mares in Australia have been sex tested but the procedure is rapidly gaining acceptance from brood mare owners both small and large.

The idea is to have your mare’s foetal sex determined by Kevin Doyle between 60 days gestation and full term. During the last six years Kevin has sex tested over 1,000 mares and is considered a world authority on the procedure due mainly to the accuracy of his reports.

In Australia March and April are the convenient times for performing this procedure before the major Broodmare Sales.

Presently luck determines whether you buy value at the broodmare sales. A pregnant mare carrying a colt foal is worth several thousands more than a mare carrying a filly; hence it makes sense to sex test pregnant mares. Since the ratio of male pregnancies to female pregnancies sold at the broodmare sales was almost identical the figures clearly demonstrate that few mares are sex tested in Australia. Broodmare investment is not a hobby, it is a serious business and it can be rewarding, don’t just depend on luck, safeguard your high risk investment with more cardinal knowledge – have your mare foetal sex determined by an experienced veterinarian between 60 days gestation and full term and keep up with what’s been practiced in the USA and Ireland for many years.

Equine foetal sex testing is a specialised technique that is safe and accurate when done by a veterinarian skilled in the procedure, and is an inexpensive source of cardinal information. It provides another opportunity to manage breeding operations more efficiently and can influence many decisions management may have to make.

  • Equine foetal sex determination is most often done to decide whether to sell or keep a mare. The value of a pregnant mare can be more accurately assessed, and realistic sale reserves can be influenced knowing this information.
  • Sometimes a mare carrying a filly foal is worth more than a mare carrying a colt foal by a particular sire and vice versa. If a stallion has predominately more successful offspring of one sex, different stud fees for colts and fillies may be justifiable and verified by foetal sex determination made between 60 and 150 days.
  • You might want to insure the pregnancy; you might want to increase the amount insured?
  • Nominations for the coming year, in some cases, can be dependent on the sex of the foal in utero. Once the sex of the foetus is determined the owner/breeder has time to decide to book the mare back to the same stallion or to another stallion. Sometimes the decision revolves around an old mare who may have had several stakes winners or not – if she is going to have a filly, the owner/breeder might want to keep her, if she is going to have a colt, he or she might want to sell her.
  • It may be pertinent to sell or keep a weanling out of a particular mare when one knows the sex of the foal the mare will have the following year.
  • If an owner/breeder wants a New South Wales-bred foal or a Victorian-bred foal (e.g. VOBIS schemes etc.), the location of foaling can be arranged accordingly.
  • Sometimes an owner might race all foals of one sex and might sell all of the foals of the other sex.
  • Equine foetal sex determinations can help management estimate cash flow for the following year. Will the sales of offspring next year provide income surplus or deficit? Will there be increased expenses from horses in training?
  • The foetal sexing ultrasound examination can verify that the mare is carrying a single, normal pregnancy. It was instrumental in recognizing Mare Reproductive Loss Syndrome in the USA. Occasionally, a mare, that palpates as a normal sixty-day pregnancy might be carrying a dead or dying fetus, or less common gross developmental abnormalities such as Schistosoma reflexus.

These are just a few of the enormous benefits why an owner/breeder might utilise equine foetal sex determination. It should be emphasized that foetal sex determination is for identification of foetal sex only and not for attempting to control the sex of offspring. Ethics require you to answer honestly whether your mare has been sex tested or not when asked if your mare has been sex tested. Disclosure of the result does not have to be given if asked what the sex is of the foal she is carrying. Hence the strict maintenance of confidentiality when performing Foetal Sex Determination is a prerequisite.

Kevin Doyle can be contacted by telephoning 61 2 6545 9911.