Rural veterinary practice
Live cover breeding
Delivery of a foal
Sleepy foal disease
11. Live cover breeding
Since the artificial insemination of horses was introduced and became customary in the nineties, the practice of going on the road with stud-horses to breeders with mares has virtually ceased. Before then, the stud-horse owners would load their horses onto a lorry every day during the mating season (from March to August) and drive to farms in the region to have the mares be covered naturally at the farm. That is to say: behind the farm. Because there is a law in the Netherlands that dictates that activities of this kind may not be visible from the public road. So you have been warned.
If a mare is in heat, it means that she is willing to mate. That is a few days in each cycle. A mare’s sexual cycle lasts three weeks. But she is a ‘season breeder’. The period in which mares become in heat is roughly from March to September. Their fertility is at its peak in the months May and June, and therefore comprises no more than three or four cycles. It is therefore essential that a breeder knows when a mare is in heat. The best way to determine this is by observing the mare. That is to say, observing her behaviour as she comes within the near vicinity of a stallion. Among other things, she demonstrates her willingness to mate by urinating repeatedly. If the mare is not willing, then she will demonstrate aggressive behaviour towards the stallion and will ‘beat him off.’ The task of observing traditionally lies with the owner of the stallion. If the mare is found to be willing, then the owner of the stud-horse can have his animal take action immediately. But since the natural reproduction process has been replaced by artificial insemination (AI), the stallions stay at home and but few mares are observed within the vicinity of a stallion. This is not a positive development for the breeding sector. Because how can the mares demonstrate their willingness to mate if there is not a male partner to be seen for miles?
This is why some breeders have purchased a teaser stallion. That is a stallion that may make advances toward the mare, but he is not allowed to cover her. Quite a miserable task actually, as he will have to take the blows that she dishes out if she is not willing to mate. And if she does wish to mate, then he will have to leave his turn to some other stallion from which the breeder desires a foal. Using a teaser stallion has a second advantage for the stud farm: it also enhances the fertility of the mare. His presence and advances stimulate the production of hormones in the mare, which in turn promotes the ripening of an egg in her ovary and the ovulation. This is particularly important in early spring: the ovulation does not take place in many mares during the first cycles of the season. Then, there is no point to natural breeding or AI as fertilisation cannot occur if there is no egg. It is waste of valuable sperm: a stud fee of twelve hundred euros is not uncommon for the better riding stallions and you pay even more for top-class stud-horses. That is not the price of one successful cover or a single bottle of sperm: the cover or insemination is repeated if necessary at an additional (limited) cost. On average, only a little more than half of the mares become in foal following a single cover or insemination.
The artificial insemination of cows has been customary for a much longer time. In the fifties, it became the main weapon in counteracting brucellosis in cattle. That is an infection that is contracted as a result of covering and it causes abortions in cattle. The bacterium is also contagious for humans. No, not as a sexually transmitted disease, but still very unpleasant and even fatal in rare cases. The last known case of brucellosis in the Netherlands dates back to 1993. Ever since, the cattle stock in the Netherlands is free of brucellosis. But in Belgium, for example, the infection is yet to be eradicated.
Twenty years ago, it also took a breeding infection among horses before research into the possibilities of AI in that species of animal accelerated. The infection did not concern brucellosis, but rather CEM (Contagious Equine Metritis). It quickly resulted in the end of natural breeding in the horse-breeding sector and therefore the end of the road stallion. Nowadays, stud-horse owners drive their cars to their clients with a cool box containing small bottles of stud sperm in the boot. The sperm is usually collected that same morning at the stud station where the animals are stalled. The sperm of some of the stallions has been frozen. These are stallions that are abroad for competitions, for example. The mares are inseminated in their own stable without ever seeing a stud-horse.
Things still went quite differently in the eighties. It is spring and Patricia is in heat. The stud-horse owner has received an early morning call, catching him before he takes to the road with his lorry. This time of the year, the daily road trip easily covers a few hundred kilometres. You can get in touch with him via the car phone (GSM did not yet exist), but if he is already in the southern province of Limburg, he will not be happy with a roundabout route to Den Dungen in Noord-Brabant. It is time for coffee when the lorry stops in the parking area next to a company. When the engine is cut, loud thumping and neighing can be heard from behind the loading platform. The boss and his hands exit the canteen to have a look at what is going on. The loading platform is lowered and the stud-horse stumbles down the ramp. He raises himself up high, his eyes and nostrils are open wide and he is belching his breath like a bellows. His neighing thunders far down the street and he is turning around impatiently on his lead rope: where is that mare? Because he is perfectly aware of why he has been unloaded from the lorry. He dances along the path leading to the stable, his head held high, the neck curved: a model of masculine strength and majesty.
The popular stud-horses are very busy this time of the year: they service five or more mares per day, and sometimes up to ten mares. And they do so every day for a few months. So coffee time may very well already be the stud-horse’s third service address that morning. Despite so much sexual activity, his desire to be of service scarcely fades. Only the number of sperm cells that the stud-horse produces per service will be more or less halved with each subsequent mare that he covers. And so it will surprise no one to learn that there will also be a few ‘return visits’ required among the mares that he services: animals that are serviced later on in the day will get much less than a full load.
Other work to do
Upon leaving, five minutes after his performance, the stallion has calmed down considerably. As the lorry drives off the property, the boss turns to his hands: “Look, all you guys should be just like that when you arrive at work in the morning.” The response is immediate: “We can do that, but you will have to give us other work to do”.
© Leo Rogier Verberne