Feeding During the Last Three Months

An unborn foal doubles its size during the last 3 months (last trimester) prior to birth, increasing the nutrient demand on the mare with this rapid rate of development, as well as the elevated need in preparation for milk production by the mare at foaling. A heavily pregnant mare should be provided with a higher energy diet containing more concentrate to provide energy, as well as protein, calcium and other essential nutrients to fuel the growth of her unborn foal.

Joint and Bone Formation

Studies in Holland by Dr. Van Weerin have shown that a young foal has only “once in a lifetime” chance to form sound, flexible cartilage and tendons, starting from around 6 months of pregnancy when cartilage and collagen begins to form and then finally matures by 5 months of age.

HANDY HINT

Aim to increase energy and protein levels by 10% per month to meet needs by adding an additional 200gm concentrate per 100kg bodyweight (remember the unborn foal adds 10% to the pregnant mare’s bodyweight). In the last month before foaling, a heavily pregnant mare is often unable to consume a large bulk of feed due to less hindgut room, so hay should be limited to 1% of bodyweight (5kg in a 500kg mare) and the remaining 1% made up with a concentrate grain, pellet and chaff mix to meet nutrient needs.

HANDY HINT

Provide pregnant mares with ample opportunity to exercise, often most easily managed by locating waterers and feeders at opposite ends of a paddock to encourage exercise. Note: Overweight mares confined to hilly country have a higher incidence of Uterine Distortion Syndrome (UDS) with bent and deviated legs in newly born foals. UDS is thought to be caused by compression of the unborn foal in womb during the last 2 months before foaling as fat mares walk to graze in hilly country. It is advised to shift heavily pregnant mares to flat, but well drained, pastures.

Vaccination

A booster injection of tetanus toxoid (and Strangles if recommended in your area by your vet) should be given 4 weeks before foaling to enable optimum passive transfer of antitoxin into the colostrum milk prior to foaling, not only to protect the mare against tetanus if she is torn at foaling, but also to ensure that the colostrum (first milk with antibodies) contains a source of antitoxin to the new born foal. Many stud farms give an additional tetanus antitoxin injection to the newborn foal to ensure optimum protection against tetanus if the germ is taken up through the umbilical stump. Consult your vet.

Hoof Care

Many heavy pregnant mares become uncomfortable when their hindlimbs are lifted and positioned for routine hoof trimming during the last month of pregnancy. It is good practice to trim the mare’s hooves about 4 weeks before foaling and repeat again about 4 weeks after foaling once the mare is not as ‘foal proud’ and anxious when being handled. Consult your farrier.

Avoid Excessive Condition

It is important to try to maintain a pregnant mare in a ‘trim’ condition, preferably with a ‘fleshy covering’ and last 2-3 ribs just covered. Heavily conditioned or overweight mares are more likely to have difficulties at foaling and, in fact, produce reduced volumes of lower protein milk after foaling.

HANDY HINT

Always locate heavily pregnant mares in a well drained paddock, preferably with a firm, sheltered rise or mound so that they can move away from wet, low lying areas during rainy periods to keep their hooves (hind hooves in particular) dry and better able to support the increased hindlimb loading during late pregnancy (up to 70kg, consisting of a 50kg foal, 20kg fluids and membranes, in a 500kg mare).