Undoubtedly the smartest thing the Standardbred industry ever did several years ago was to change their breeding season to the first of October—foaling from September 1st; breeding from the 1st October.
Undoubtedly the stupidest thing they ever did this year was to change it back again—foaling from 1st August; breeding from 1st September!
The Thoroughbred industry has done it this way for eons of course but they get away with it because many of their owners are prepared to keep their dry mares under lights from the shortest day back in June. Standardbred owners are less inclined to go to this expense.
Without lights, mares examined in September will fall into four categories-
- In foal
- In anoestrus
- In spring oestrus
- In dioestrus.
Let’s look at each category—
In foal Obviously we have to wait for them to foal before breeding them again. These mares are not affected by the time of year.
In anoestrus. These mares have not recognised that the breeding season has begun. They have not cycled since the previous summer. They have no corpus luteum. Prostaglandin only works by getting rid of a corpus luteum so there is no point in giving it & it may even be detrimental. There is basically nothing that can be done with these mares except to wait until they are ready to cycle on their own.
In spring oestrus. These mares have recognised that it is spring & have started showing & are in season for prolonged periods often with small follicles that will not ovulate. This is nature’s cleaning period; their cervixes are relaxed so they can drain any excess fluid & they have an acid uterine environment which encourage them to clear naturally any bacterial uterine infections that they may have carried over from the previous season. These mares will show to the stallion. This is the one that brings owners & stud masters unstuck because it can last for prolonged periods. Owners see them showing (interpret this behaviour as cycling) & don’t understand why they cannot be bred.
Of course there are things that can be done to shorten this period. Cumates & ovulatory drugs may bring on an ovulation but they shorten nature’s cleaning efforts & the resultant fertility is low. Most mares have a much higher fertility on their second cycle of the spring.
In dioestrus. These mares (a small percentage unfortunately) have already begun to cycle (ovulated) & are ready for prostaglandin. They will be ready to breed when they come into oestrus. This is the stage we expect to find in mares kept under lights. Sadly, in a small percentage of cases, the corpus luteum that we see on scanning may be from mares that have cycled early in winter or throughout the winter. Occasionally these mares switch off at the start of spring & are very difficult to get cycling again.
Most of these problems are overcome with a start of the breeding season in October. If you are paying your veterinarian for individual scans (e.g. your mare is not at a stud & under contract) you can run up a significant veterinary fee in September without achieving anything.
My recommendation is to ignore the official breeding season & start getting your empty mares examined in October when the incidence of spring oestrus will be much lower.
Good luck to all breeders for the current breeding season.
Max Wilson & Robyn Woodward
Wilson’s Equine Veterinary Services
Equivet Australia
Approved By Dean Baring www.harnessbred.com
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