Horse Pregnancy

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Horse Pregnancy

The period of pregnancy in the mare is about eleven months. Determination of pregnancy can be made in three ways:

1. Conformation. The conformation of a horse is the key to its progression. Conformation is basically the way the horse has been put together. The body should be in pleasing balance with the limbs and should be well-proportioned. The horse is a working animal and its working ability is determined by the condition of its limbs and feet. Poor conformation of limbs may contribute to lameness.

2. Laboratory Testing. There are two types of tests: blood tests which are done between sixty and ninety days after service, and a urine test which is done between two hundred and two hundred and seventy-five days after service.

3. Manual Testing. This is done by a veterinarian who examines the mare internally via the rectum. This requires considerable experience and dexterity if it is to be carried out with any degree of accuracy. An early indication can be given at twenty-one days, although a final legal decision is not possible till six weeks into the pregnancy. This is called a 42-day pregnancy test, on which a certificate may be issued.

Ultra Sound Scanning

This is a non-invasive technique which is harmless to the operator and the mare. An electronic probe sweeps the area under examination. Echoes, produced as the beam scans the various organs, provide a clear, moving image on a display screen. Accurate diagnosis of pregnancy can be made as early as 14 days after ovulation.

Manual and ultra-sound testing gives a much quicker result and allows time for rebreeding if the mare is not in foal; the other tests are used if there is any danger to the vet, the mare or the foetus in manual testing (for example, very highly strung mares, or mares that abort easily).

The Hours Before Birth

Between six and forty-eight hours before foaling, a small amount of clear.thick, serum-like material oozes from each teat canal (there are two canalsper teat in the mare). This serum hardens to a wax-like material, and oncethis appears most mares will foal within the following twelve to twenty-fourhours. But some mares show little or no wax. A particular mare will usuallybe constant in her foaling procedure and any unusual behaviour should berecorded, especially where the mare is not seen to wax at all.

Vulvas of sutured mares should be cut at least a week before the foal isdue, to prevent tearing.

In most mares the pelvic ligaments show slackening twelve to eighteenhours before foaling. A hollow appears on either side of the root of the tail.and the tail loses its power to hug down over the perineal region.Unfortunately, however, mares do not always follow rules. A mare can ap-pear days off foaling when examined at midnight, and yet have a foal severalhours old at her side at dawn.

Foaling

During the first stage of labour the mare may paw the ground, look at herflank, kick at her belly, crouch, catch her breath or wander uneasilyaround—and then resume feeding. This may be repeated in ten to fifteenminutes. From this point on, the mare should be kept under supervision. Itis preferable to keep out of sight and not to interfere unless there is anobvious emergency.

There are no fixed rules for the act of foaling. Most mares lie on their sideto foal, raising the upper hindleg at each contraction. At this stage the labourpains, which have been intermittent and of short duration, becomeintensified and succeed each other at shorter intervals.

When the cervix has relaxed sufficiently, the contractions will force thefluid-filled membranes through the vulval lips of the mare. About five min-utes after the appearance of the water bag, the first leg appears and the bagbursts, discharging about 4 litres of placental fluid. After a short rest thesecond leg appears 8-10 centimetres behind the first. Never pull on the less-advanced leg in an attempt to level it with the first, as this invariably resultsin fractured ribs for the foal. Both feet should appear with the soles facingthe mare's hooves, and the foal's muzzle between the knees. Any othercombination of the above, such as head only, or soles up, requires a vetimmediately, as the foal is probably presenting abnormally.

One of the most important conditions to prevent is the recto-vaginalfistula, where the foal's foot ruptures the roof of the vagina and tears itlongitudinally as the mare strains. This will be evidenced by a leg beingcaught in the roof of the vagina, and possibly even the appearance of a hoofthrough the anus. In this case a sterilised, lubricated hand should be placedin the vagina around the offending leg and the leg pushed towards themare's head and redirected into the vaginal cavity. This should be doneimmediately the problem is noticed. This condition is most common inyoung mares foaling for the first time but may also occur in older broodmares with deep bellies. Repair of the tear is a complicated surgical pro-cedure requiring skilled veterinary attention.

Occasionally the mare will expel her foal until its hips become wedged inher pelvis. In this event she needs help, and delivery must be made quickly or the foal will be lost.

the foal slowly from side to side. If this is not successful. the attendant shouldpass a sterilised, lubricated hand into the birth canal, over the rump of thefoal and grasp the tail. A hard pull on it as the mare strains almost alwaysbrings the foal.

Allow the umbilical cord to tear of its own accord about 3-5 centimetresfrom the navel.

If the mare has not passed her entire afterbirth within three hours offoaling it should be considered retained placental membrane. A vet canapply medication to help the mare pass all of the membrane and contractthe uterus.

Do's and Don'ts

• Don't hurry the mare or hover over her.

• Don't touch the mare or foal while the labour is progressingnormally—that is, let the mare foal as decreed by nature.

• Don't hesitate to call your vet if the mare is in trouble. Trouble is indi-cated by the mare straining for more than one hour without the appearanceof the foal; the appearance of the head and no feet, or the head and onefoot, or the feet and no head. Once normal foaling begins the foal is bornwithin 15 minutes of the appearance of the feet. if waiting for help, keepthe mare walking, provided the foal is not hanging out.

Make sure the membranes over the foal's nostrils are torn; if this does nothappen by the time the head is out, quickly tear them away with yourfingers.

'Foaling heat'

According to most data, the average gestation period for thoroughbreds is about 340 days. Data indicate that colts are generally carried longer than fillies. Disease can influence the length of gestation. Normally, the mare has a 'foaling heat' soon after the birth of the foal, usually on or about the ninth day. This is usually a short oestrus, but the mare will accept the stallion and, under favourable conditions, will conceive. If the mare has had a rough foaling with evidence of bruising and haematomas of the birth canal, it is advisable not to breed at this time, nor should a mare that has foaled for the first time be rebred at foal heat, as she is more likely to have suffered damage.

Some breeders hesitate to breed on the ninth day for several reasons:

• The mare showing signs of oestrus may not be near ovulation.

• There is a possibility of uterine infection.

• Traumatic injury to the birth canal often goes unnoticed.

• The womb of a mare kept in a box for nine days after foaling has rarely contracted properly, and while there may not be infection the presence of secretions and retained debris is unfavourable for conception.

For these reasons, routine genital examinations at the seventh or eighth day after foaling are indicated. If the mare is not mated on foal heat she will normally cycle again eighteen to twenty-one days later. Failing this, it will be fifty to sixty days.

After Foaling

Always spread the membranes out on the ground and make sure both uter-ine horn tips are present. Many mares who retain the afterbirth for morethan three hours will have difficulty conceiving at the next foaling heat.Never pull the membranes out manually, unless under veterinary supervis-ion. Keep the membranes for your veterinary surgeon to examine.

The following should be carried out after foaling:

• Enema for foal (100 millilitres of warm soapy water).

• Navel swab of tincture of iodine.

• Shot of wide-range antibiotic to both mare and foal, especially if there is ahistory of infection.

• Tetanus anti-toxin or toxoid, to both mare and foal.

• Drench of 4.5 litres of mineral oil for the mare to prevent post-partum colic.Repair of episiotomy (cut vulva) or tears.

• Wash mare's hindquarters with disinfectant.

If the mare fails to lick the foal and show it affection, a little table salt rubbed on the foal's neck and shoulders may help. A little of the dam's milk rubbed on the foal's muzzle and face may overcome resentment. A mareshould be supervised until she thoroughly accepts the foal and allows it tosuckle. On rare occasions this may take as long as a week, in which casetranquillisation may be used to allow the foal to suckle. Very rarely a maremay reject the foal so savagely that it is best to bring the foal up by hand,if a suitable foster-mare cannot be found. Consideration should be given toculling such a mare from the breeding programme.

Horse Weaning

Weaning can take place between four and seven months. The guiding factorshould really be the dam's condition. For instance, a fat mare with plentyof milk can suckle her foal for six months or longer, particularly if she isempty (not in foal again) and therefore does not need to nourish a foetusas well. A day or two before separation, accustom the mare to having herudder and teats gently handled and milked.

On the morning selected for weaning, the mare should be walked to hernew paddock leaving her foal behind in its usual box with both upper and lower doors shut. It is important that the foal is strictly confined in a safeenclosure, which must have solid high walls. The mare should be placed ina sturdy yard well out of earshot of the foal's cries. The mare's udder shouldbe inspected twice a day and she will need to be milked to relieve thepressure. Do not strip her out completely as this only stimulates further milksecretion and production.

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