Colostrum is an essential ingredient to the new life of a vibrant newborn foal. So, a foal nursing shortly after birth is a very good sign. The first milk produced by the mare is energy and nutrient dense, most renowned for its ability to “jump-start” a healthy immune system. A vigorous foal stands and easily nurses within one to two hours of birth. Thereafter it will nurse every hour for the first 12 hours, consuming approximately 250 millilitres/one cup of colostrum each time.
Foals are born with a functional immune system, but it takes a few months for the young horse to produce its own antibodies. Until then it is reliant on what is provided through the mare’s colostrum.
The physical appearance of colostrum is different than that of milk. It is viscous, sticky like honey, and green or yellow in colour. Colostrum is produced in the mare’s udder during the last two to four weeks of gestation in response to hormonal changes. It contains concentrated immunoglobulins (antibodies) which come from the mare’s bloodstream. This is a specific process that provides the newborn foal with protection against pathogens found in its new environment.
ALMOST IMMEDIATE NEED
Early consumption of colostrum is very important, ideally within the first one or two hours after birth, as there are specialized epithelial cells in the small intestine that allow for the absorption of large molecules, such as maternal antibodies and other colostral proteins. Once the foal has suckled a certain amount, or 24 hours goes by, whichever comes first, these special cells die off and the intestines no longer absorb any large molecules.
Foals that do not drink anything for many hours after birth but are exposed to manure, dirt, mud and other unclean environments may ingest bacteria into the mouth and therefore their gut. Once in the gut the bacteria may be absorbed into the bloodstream by this same mechanism, predisposing the foal to systemic infections that can be life threatening.
When a foal does not ingest a sufficient concentration of immunoglobulin/ antibodies as a result of inadequate colostrum intake, it suffers from failure of passive transfer. This can stem from a foal’s inability or unwillingness to nurse. The mare might also contribute to failure of passive transfer if she rejects the foal, is injured, ill, or prematurely drips milk. Premature dripping of milk, known as streaming, dilutes colostrum, thus the foal does not get the optimum concentration of protein and antibodies for fighting infection.
A commercially available rapid test kit can measure the immunoglobulin level in the serum of a foal. It can give a good indication of the foal’s status, especially when the results are combined with information about the foal’s behaviour and nursing history since birth.
Meconium, the first feces passed by the foal, is a dark-green sticky/tacky mass that accumulates in the bowel during fetal life and is discharged shortly after birth. It is not uncommon to see tags of sticky greenish meconium on the foal’s hindquarters within six hours after birth. This can be evidence of a healthy ingestion of colostrum, which provides laxative qualities.
A foal’s environment must be evaluated in order to determine whether the foal needs supplemental colostrum, a course of antibiotics or, in the case of foals older than 24 hours, intravenous plasma or gammaglobulin. A foal which experiences failure of passive transfer has more potential to get sick if subjected to unfavourable environmental conditions, like dirty stalls or paddocks, rain, cold, or overcrowding.
If the foal is too weak to nurse, is injured, or is rejected by the mare, the mare can be milked of her colostrum and the foal fed with a bottle. If the foal will not accept a bottle, a veterinarian might choose to administer colostrum through a nasogastric tube – through a nostril, down the esophagus, and into the stomach. If the problem is with the mare, then frozen colostrum from another mare will suffice. If natural colostrum is not available, a veterinarian can administer commercially produced plasma, gamma globulin, or oral IgG. However, commercial products are not as effective as a mare’s colostrum in fending off specific infection and disease.
The need for colostrum is a rare event. However when the need arises one can often find that several Internet sites are available to help owners locate frozen mare colostrum. Veterinary clinics may have some colostrum available or can be a resource for locating some. If mare colostrum is not available, calf colostrum can be used. While this is not the first choice, it is highly preferable to no colostrum at all. Frozen colostrum is best thawed slowly, never in a microwave, and warmed up to body temperature. It can then be fed to the foal by bottle, or if necessary your veterinarian can give the colostrum through a stomach tube.
In the event that the foal dies the mare’s colostrum can be collected and frozen for future use. It could make a difference in the life of another foal.
Whenafoaldoesnot ingestasufficient concentrationof immunoglobulin/ antibodiesasa
resultofinadequate colostrumintake,it suffersfromfailure ofpassivetransfer.