Horse Tales
Winter Solstice, January 1 Are Important Dates for Horse Breeders

Welcome to December, once more. There is a steady wind circling the house, and there's a light snowfall on the ground. I went up to the barn at noon today, to check on our horses, and I took a glance over the field at our neighbor's five brood mares in the near pasture. All animals were content enough, munching on hay or field grasses sticking out of the snow, in spite of the cold. Every time I go to the barn, I tend to look across the way at the mares. Perhaps it's a maternal thing, because with mares in foal, you never know.

Most people, even those on Mackinac, don't have the slightest idea of how long the gestation period is for horses, although Islanders do have a day-to-day interaction with them. Most people (and those who really like horses) are unaware how long it takes for a foal to develop. Actually, we humans have had quite a bit to do with altering breeding cycles, breeds, and even the foaling process. As December deepens, the foals of my neighbors continue to develop. The upcoming winter solstice December 22 has historically been an important day for horse breeders, along with the first day of January.

Equine gestation is the period from conception to birth. It averages 11 months, or 340 days, given a range of 320 to 370 days. Some mares have actually produced a healthy foal during their 14th month, but this is rare. A foal born before 320 days is premature, and although it has happened, some horses can be born at fewer than 200 days, and live; usually, though, they're too young to survive.

Although most horses don't reach their full height until the age of five, they can be ready for reproduction by an early age. Mares tend to be between the ages of three and four, and usually can produce a live foal. Some stallions, such as the pony "Magic" I met in Ireland, can impregnate a mare at as young as one year old (hence his name). Mares are naturally "season breeders."

The true mating season is comprised from a number of factors: climate, rainfall, nutrition, and daylight. It has been proven that the length of daylight has a direct effect on the activity of mares' ovaries. The effect is through the optic nerve and the pineal gland. As the daylight lengthens, melatonin secretions trigger the rest of the hormones and ready them for reproduction. In simple terms, the heat cycle of the mare begins a more aggressive activation.

In the old days, the horsemen counted down from the winter solstice to the longer days of light in February and into March, and then would turn their mares out with a stallion. Conception rates are usually at peak in June, so the advantage of the natural breeding season is that when a mare is bred in the summer, she foals in the spring, which is when natural conditions are best for raising a baby.

The five brood mares I observe are due to foal as early as March, and as late as the third week in June 2008. They're part of an "operational system," however, and the mares were artificially inseminated (AI). This is a procedure in which semen is collected from the stallion and inserted into the reproductive tract of a mare by a veterinarian. It can be fresh, or cooled, allowing the mare to remain on the farm, and the stallion comes from as far away as another continent, in some cases. Not all breed registries allow this, but in some cases, the selective breeding has been an enhancement. Breeders can have better control of due dates and foaling by having a mare bred this way. They also have a workable approach with their veterinarian, and are up-to-date by the use of ultrasound, to know within a few days whether or not the mare has conceived.

The American Jockey Club is the only U.S. organization that prohibits AI. All breeding must be live, recorded, and have witnesses.

The Jockey Club also was the organization that mandated January 1 as the official birth date for all registered Thoroughbreds. In the Southern Hemisphere, the date is either July 1 or August 1. This is regardless of the actual day and month it's born. The system is used to qualify horses for races that are limited to a certain age group. To say that breeding is all tied into economics is true.

Some horses do conceive twins, although healthy twin births rarely survive. In the case of twins in assisted breeding, close monitoring will show evidence of twins, and usually the veterinarian will be called in to retain the bigger and better developing embryo, and not the smaller. Mares naturally abort illformed species, like most mammals. Those who birth a non-breathing foal after 300 days are considered to have had a stillborn foal.

Following birth, a foal usually can stand in minutes, and it will try to nurse within a half hour. These newborns are a delight to see, with long, long legs, looking more deerlike than equine. Those long legs enable a basic skill for survival. As a foal matures, the legs grow more slowly. By the time the foal is a year old, he should be more than half of his adult height. Keep in mind, though, that some breeds mature later than others.

Horsemen will tell a person a lot of things. There are some interesting statistics on mares and foals. The average mare will have five to six foals. Many mares can breed into their 20s. One of my personal favorites is the documented case of an Australian draft mare named Bessie, who was 46 years old when she died in 1938. Her career was that of a draft horse, not just a mare for breeding. Yet, in her time, Bessie bore 36 foals into this world. Two of her foals were stillborn; the other 34 lived.

On that note, have a very happy holiday season, the best of wishes for a good New Year, and, of course, "a-neigh in the manger" to all.

Candice Dunnigan is an active member of the American Equestrian Association, the Waterloo Hunt, and the Mackinac Horsemen's Association. Seasonally she resides at Easterly Cottage.