Dr Bruce Howlett answers some questions on horse breeding

-Dr Bruce Howlett answers some questions on horse breeding

Horse breeding - Dr Bruce Howlett of Stabler and Howlett Mackay With the 2018 horse breeding season still a few months away I sat down with Dr Bruce Howlett to ask a few questions about the whole horse breeding process. 

When is the right time to decide to breed your horses?

“Mare owners considering artificial insemination really need to be getting organised now. Choose your stallion and get a contract in place. There are often discounts available for early bookings or pre-payments at this time of the year. Also, the busy or more popular stallions will have a limit on the number of mares they’ll book, so if you leave it too late you can miss out on the stallion you want.

The horse breeding season starts officially on the 1st of September, however, depending on the weather, often our mares in the North won’t cycle reliably until late September, so we have quite a tight breeding window, because what we find is that the humidity and heat after Christmas make breeding in January and February quite unrewarding.”

What’s involved with breeding a horse? What to expect if you’ve never done it before.

“Coming into the breeding season from August onwards we like to perform an external examination of the mare’s reproductive organs as well as an ultrasound examination. This is to detect any issues that may impede our ability to get the mare to foal. These may include physical damage from injury to the vagina or vulva, and abnormalities in the uterus and/or the ovaries.

Given that the pre-breeding issues have been resolved, we then like to have the mares presented to our breeding farm at Leilavale from say mid-September on, preferably when they first start showing signs of oestrus (or ‘heat’).

What happens then is we get the owners to leave the mare with us and we take care of things from then on. We ultrasound those mares twice a day to monitor what their uterus and ovaries are doing.

Dr Bruce Howlett scanning a mare at “Wieta” Middlemount. Our mobile horse stocks mean we can safely perform reproductive scans on property.

Dr Bruce Howlett scanning a mare at “Wieta” Middlemount. Our mobile
horse stocks mean we can safely perform reproductive scans on property.

So what we like to see is uterine oedema increasing as the blood supply to the uterus increases which we can see on ultrasound, accompanied by (hopefully!) a follicle on one of the ovaries becoming a dominant follicle. When that dominant follicle gets to 35 mm we’re in a position to control the mares time to ovulation. Then what we do is order semen from the stallion’s owner or the breeding farm where the stallions stand. Once we know an approximate delivery time for the semen we then give the mare an induction agent which controls ovulation time.

Obviously, we try and control ovulation time to shortly after we receive the semen. So ideally, inseminate the mare just a few hours before ovulation. Some hours later we rescan and hopefully, the mare has ovulated by then. We then lavage the uterus, i.e. flush fluid in and out of the uterus to take the debris and excess fluid from insemination out of the uterus, providing a healthy environment for the conceptus to come down out of the fallopian tube into the uterus where it will hopefully grow for 11 months giving us a foal.

Fourteen days post ovulation, we will scan for pregnancy and if successful we then will go to a 35 and 42-day scan to confirm the pregnancy. If the mare is not in foal, the owner then has the option of inseminating again on the next cycle, which will begin at day sixteen post ovulation.

So that’s the chilled semen AI program put it simply as I could, the variation is, of course, frozen semen, which we’re using increasingly because it gives us access to stallions not just in Australia.

The difference is with frozen semen we have it in the tank. We control our ovulation time, to suit us I suppose, and then with frozen semen, we tend to scan hourly until we’re on the point of ovulation and inseminate with frozen semen at ovulation which gives us good success.

I’d like to emphasise that once your mare is on our property we take care of the process from then on. All you’ve got to do is organise your contract and get the mare to us and the process as it is in our hands.

Horses grazing at “Leilavale"

Horses grazing at “Leilavale”

In terms of what to expect I guess from a financial point of view, you need to be well researched in what’s realistic financially to enable you to have a decent go at artificially breeding a mare. With good quality semen and a healthy fertile mare, you can realistically expect from single insemination a 70 to 80 percent chance of pregnancy. But it’s important to remember the 20 to 30 percent. You’ll probably need to be prepared to have two rounds of artificial insemination before you start because giving it one chance is a bit unrealistic and you may just be in that 20 to 30 percent range.

Be mindful your chances of success are affected by the quality of the semen tremendously. I can do everything perfectly but I have no control over the quality of semen that I’m sent. Obviously, if the quality of semen is poor the chance of getting the mare in foal declines markedly. So I encourage people to do some research about the semen quality of the stallions that they’re using so they know how many pregnancies were achieved out of how many inseminations the previous year.”

Are there any supplements or feed that you should be using or conditions you should be looking out for?

“Mare health is a very important factor in the success, or otherwise of breeding. We look firstly at body condition – we like to see mares in good condition on an ascending plane of nutrition. Skinny mares will not go in foal.

Also, just an issue with mares with itchy skin- they tend to have poor pregnancy rates. I think this is related to the inflammatory cells generated from having this itchy skin localising in the uterus which decreases your chances of pregnancy. I strongly believe skin problems need to be resolved before breeding.

Vaccinations are also very important. As a base, mares need to be currently protected against hendra, tetanus and strangles. Also, there’s an option of doing them with a herpes vaccine.
Mares should be dewormed, preferably within a couple of weeks prior to arrival on the farm, with either Equest Plus, Imax Gold or Equimax. The cut-price wormers are unreliable and we’ve seen several mares that have been “wormed” that have come to the property with worms.

In terms of nutritional supplements, given the pastures that exist in most of our horse paddocks in the district, the most important thing is a calcium supplement. Obviously, calcium deficiency will decrease pregnancy rates. A good quality vitamin and mineral supplement with significant available calcium levels is important. A few examples would be the Pryde’s EasiFeed High Calcium Balancer Pellet, Folactin Red or LIVAMOL powders.

If we get mares that are in good health and in good condition our chances of achieving pregnancy is a lot better.”

Why come to Stabler and Howlett to breed your horse?

“I think we take particular pride in looking after people’s mares and foals, the mares are in individual paddocks, they’ve always got grass to eat and they’re fed once or twice a day as appropriate with really high-quality nutrition.

We’ve got the equipment that enables us to do our job really well with high-quality ultrasound machines, safe facilities, digital sperm analysis etc.
Personally, having been doing it for 15 years or more, I feel my technical level of expertise is very good. I think I’ve got a good feel for what mares are doing and I think being involved in the horse industry and having a lot of contacts in the industry really helps.

You know we have contacts in all states of Australia, be they vets or horse owners and competitors and that really helps in breeding season, those personal contacts really help because one of the hurdles is the logistics of getting semen when you need it or getting the semen that you want and certainly knowing the people that we know makes that process a lot easier every year.

But yeah I guess it’s similar to everything else we do, we take a lot of pride in doing it well. We regard the whole horse breeding thing as a collaboration between us and owners and the stallion owners, which is tremendous. You know you’re breeding your owners’ best mares and you’re breeding them now to any horse on earth, to some really good stallions.”

Finally, are there any results you’ve been particularly proud of?

Young colt in the stallion enclosure at “Leilavale"

Young colt in the stallion enclosure at “Leilavale”

“The foals we produce are quite amazing and it’s great to see those foals come back with their mums or even see them born at Leilavale. Then we see them then become successful competitive horses in their respective discipline. Yes, there’s a lot of satisfaction there when you get it right.

Also, there’s a lot of satisfaction with mares that are problem breeders, where you’ve got an owner who’s obviously willing to make the commitment to the process. We find we can get those mares in foal and it’s very satisfying to see that.”


Thanks to Dr Howlett for taking the time to answer these questions and if you’re thinking of breeding your mare this season please don’t hesitate to get in touch early to discuss!

By |2018-07-12T10:57:54+00:00July 12th, 2018|Horses|0 Comments