Henry, a bay Irish Draught Colt, was born on 28th June 2018 to Irish Draught mare, Molly. He was born without complication, and Molly successfully passed the afterbirth soon after. Henry was remarkably large when born, and consequently struggled to find Molly’s udder and latch on to suckle. After struggling for a few hours, Vet Rhiannah attended and together with Henry and Molly’s owner they attempted to encourage him to latch on by himself. However he was so big and strong that this proved an impossible task, so the decision was made to milk the colostrum from Molly and administer it to Henry via stomach tube to ensure he received adequate colostrum in the first 6 hours.
Molly and Henry were then left alone to bond, in the hope that the colostrum would give him the strength to start to feed on his own. Due to the excessively hot temperatures last summer, if this failed to happen then both mare and foal would be admitted into hospital to ensure they were progressing normally. Fortunately, a few hours later Henry was feeding confidently by himself, so they remained at home to be closely monitored.
The following day Rhiannah returned to measure Henry’s blood IgG levels to ensure he had received adequate antibody protection via colostrum. A newborn foal cannot receive too much colostrum, however the minimum volume required for a standard 50kg foal would be about 4L of good quality colostrum in the first 6-8 hours. Obviously if the colostrum is of poor quality then a greater volume would be required. Likewise if the foal is larger than 50kg then a greater volume would also be required (as in Henry’s case).
Colostrum is produced only once, so leakage of colostrum prior or post foaling can result in a reduced supply for the foal.
After 24 hours the colostrum (containing lots of antibodies) is replaced by milk, which has low levels of antibodies.
It is absorbed by special cells in the lining of the small intestine in the first 6-8 hours, however these cells can also absorb bacteria which can be very dangerous for the foal. This is why it is so important to have a clean foaling box and clean mare with no access to other horses, to minimise the bacterial burden that the foal comes into contact with and therefore can absorb in the first few hours of life. After 12-24 hours absorption across the intestinal lining declines to almost zero.
This is why we measure the foals blood IgG levels after 24 hours, as prior to this the levels may still be increasing and therefore we may get a falsely low result.
An ideal IgG result showing excellent passive transfer would be >8g/l, 4-8g/L would indicate a partial failure of passive transfer. Less than 4g/L would indicate total failure of passive transfer, and a blood plasma transfusion would be required in order to give the foal a chance at survival.
A stable side snap test can give approximate results in 10 minutes, but if there is any doubt in the IgG levels then the sample must be sent off to the laboratory to get quantifiable results. Thankfully, Henry’s results came back as convincingly above 8g/L, so it was not necessary to perform any further testing.
December 2018 signalled the start of weaning for Henry. In the wild horses are weaned gradually, usually due to the mare giving birth again, and the previous year’s foal having no choice but to leave mum and integrate with the rest of the herd. In the domesticated scenario we have to undertake a different approach but it is vital to do this in a controlled manner, and minimise stress to the foal and mare. Milk is primarily digested in the small intestine, but as the foal develops, there is a gradual change to become a hind gut fermenter as they mature and begin to eat other feedstuffs. It is really important that the introduction of feedstuffs other than milk is done slowly, to not only allow the digestive system to adapt but to promote slow, controlled growth and protect the joints.
Most foals are weaned after 6 months of age, however it is possible to successfully wean after 4 months if required due to health concerns. In the 4 weeks prior to weaning it is important to feed increasing amounts of foal creep feed (starting slowly of course), to allow the digestive tract to adapt to a non-milk diet, backed up, of course, by copious forage. When the time comes to actually separate the mare and foal, approaches vary. Some choose to gradually introduce time spent apart, whilst others choose to separate them fully on day one. Whatever the approach, it is absolutely vital to make sure the newly weaned foal has company – it is never appropriate to leave the foal by itself, and will very likely lead to problems. Not only do they need company, but require social interaction with other equines for normal development and learning acceptable social behaviour.
Whatever the method chosen it is vital to minimise stress, as this has a knock-on effect on the foal’s immune system, and leaves them vulnerable against infection. Thankfully, Henry was successfully weaned, and now happily lives with his older gelding friend. Hopefully he will continue to progress and do well – next step… castration!