No one looks forward to weaning time. There's nothing quite as heart-rending as the sound of a panicky foal, galloping up and down the fence line calling desperately for the mother who's been taken away--unless it's the sound of his dam calling back! It's no wonder so many horse owners dread this duty; it pushes the guilt buttons like nothing else.
Still, we know that weaning is a necessary part of the process of growing up for a foal. It's also important for the mare's well-being, particularly if she has been bred back and is carrying next year's foal, because nursing makes significant demands on her nutritional resources and can leave her looking like a hat rack. Wrenching though it may be, it's got to be done. The question, then, is how to make weaning as painless as possible.
The presence of another foal appears to be intimidating for many new weanlings.
Researchers describe an animal as in a state of stress if it must make abnormal or extreme changes in its physiology or behavior to cope with the adverse effects of its environment or management. Under that definition, weaning definitely qualifies as a source of stress to young horses. Minimizing stress during the weaning process is more than a matter of peace of mind (or peace and quiet). Studies have demonstrated that foals which suffer undue stress when being weaned can lose their appetites and lose weight--and later, when they recover, they often undergo a sudden growth spurt. The result of this dip and surge in the growth curve of a young horse sometimes is a cause of developmental orthopedic disease (DOD), the condition in which bones and joints begin to develop abnormally, causing contracted tendons, physitis, or even bone cysts in the joints of the limbs. In contrast, foals which undergo the minimum amount of stress during weaning continue to grow on a more even keel (their heights and weights increase in smooth increments). And that, researchers say, makes them far less predisposed to DOD.
In addition, stressed foals are prone to gastric ulcers (which can further delay their growth and development), delayed reproductive function, and a host of opportunistic bacterial and viral infections, such as strangles, influenza, equine herpes virus (formerly known as rhinopneumonitis), and salmonella infection. The reason is that under stress, horses experience increased levels of cortisol (a hormone secreted by the adrenal cortex) in their bloodstreams. In the short term, a raised cortisol level is a good thing--it assists the '"fight or flight" response that helps keep horses alive in times of crisis. But when the cortisol level remains high for long periods of time (as it often does during weaning), the hormone can compromise a foal's normal immune function and leave him vulnerable to disease.
A stressed foal doesn't sleep well. Foals in general need more sleep than do adult horses, and to sleep soundly, they must be in laternal recumbency (stretched out on the ground, not lying on their sternums). Researchers have suggested that the release of hormones, especially the all-important (to foals) growth hormone, and the process of cell division, are intricately related to the sleep cycle--so in a very real sense, a stressful weaning might stunt a foal's growth.
Finally, because an anxious foal is often a panicky one, undue stress during weaning can increase the likelihood of injury--either from running up and down the fence line till immature joints are overloaded, or by tangling with fence lines or with other horses. For all of these reasons, then, it's in the best interests of the foal (and by extension, his owner) to de-stress the weaning process as much as possible.
When Is He Ready?
Opinions vary as to the best time to wean foals, but most breeding farm managers aim for somewhere in the range of four to six months of age. Ideally, three things should be in place before a foal is ready to wean:
1) He should be sufficiently socialized with other horses so that he will be able to behave himself in a herd without having mother there to intervene on his behalf. This behavior usually is established early in foals which are raised in large groups, but might be delayed in foals which are raised as "single" babies or which reside on small farms. It's a good idea to make sure the foal has been introduced to a "'substitute companion"--a patient older gelding, barren mare, or even a donkey--which can serve as both a friendly face, and in some cases as a disciplinarian, to a foal about to be weaned.
2) He should be nutritionally independent--that is, he should not be deriving most of his nourishment from his dam's milk. Early in a foal's life, milk is his only food. But even from the age of a couple of weeks, he begins to show interest in the grass, hay, and grain his mother eats. From that initial curious sampling, he should progress to regular consumption of a creep ration, so that by the age of four months or so, he is deriving most of his nutritional needs from solid food, and only returns to the "dairy bar" (which by that time should be producing much less milk) on an occasional basis, and more for comfort than anything else.
3) This brings us to the third requirement of a ready-to-be-weaned foal: emotional independence. A young foal is initially a shadow of his dam--tagging along very closely to her side, and too frightened of the world and all its confusing inhabitants to stray very far. But with each passing day, a foal's curiosity gradually overcomes his fear, and his dependency on Mom diminishes as he becomes bold enough to venture forth and explore his environment. Some are naturally more gregarious than others, of course, so this might happen at different rates. A foal which is ready to be weaned is one which already spends a good deal of his time away from his mother's side. A younger foal, still emotionally dependent, would likely be far more traumatized by his dam's sudden absence than an older, braver one.
These, of course, are the preferred conditions. But under certain circumstances--such as the illness, injury, or death of the mare--it is sometimes necessary to wean a foal younger than four months of age. If you find yourself in this awkward position, recognize that the weaning process is likely to be very hard on your foal, and be prepared to provide nutritional support (in the form of milk replacers if he is too young for solid rations) as well as emotional aid (both through increased human contact, and possibly by providing him with a nurse mare or baby-sitter, such as a patient pony).
Before you wean your foal, you should accustom him to the stall and/or paddock where he will be weaned, so that he thoroughly knows the layout and will be less likely to hurt himself. It goes without saying that the area you use should be triple-checked for safety. There should be no protruding nails or sharp edges anywhere; hardware, such as buckets and hangers, should be kept to a minimum, and fencing should be high enough to discourage a foal from trying to leap over it, as well as be able to take the impact of his body without shattering or giving way if he decides to test its strength. Many farms consider tight diamond wire mesh, topped with an oak rail, to be the safest arrangement. Board fencing, while not particularly forgiving, can be solid enough to discourage shenanigans and also is a popular choice. Page wire, however, with its large, open weave, is a dangerous fence for volatile weanlings, and any fence of low visibility is a bad idea.
Planning The Separation
Before you forge ahead, put together a game plan for weaning. Many farm managers feel that weaning is stressful enough for a foal without introducing him to new surroundings and new companions at the same time--so on the whole, it's usually easier to remove the mare to another location than it is to move the foal. While mares also suffer stress as a result of the weaning process (as indicated by their raised cortisol levels, which usually persist for about 24 hours post-separation from their offspring), their greater maturity means they adapt sooner, particularly in the case of "career" broodmares which have been through it many times before.
Whether you remove the mare to another farm entirely, or just to a location out of earshot of her foal, is a matter of convenience. But whichever you choose, you must keep in mind that it will take her a few days to "'dry up" (stop producing milk). During those few days, she is likely to be sore and disagreeable, but resist the temptation to milk her out to relieve her discomfort; by stimulating the glands, you only perpetuate the milk production. Many farm managers find that reducing the mare's grain ration (or eliminating it completely) for a few days assists in the drying out process.
Do you intend to wean your foal in a paddock situation, or in a stall? This will depend on your facilities, and you should choose whichever environment is likely to be safest for your new weanling during that initial frantic phase. It's more difficult to control a foal which is loose in a paddock--but if he is in a group situation, perhaps with a "baby-sitter" gelding or older mare, he might exhibit fewer signs of stress. Truth be told, some foals fail to register that their dams have disappeared at first because they are engaged in group play with other foals in their herd. On the other hand, keeping your foal in a stall means you have better access to him should he need attention (or just human comfort), and the confinement probably reduces the overall risk of injury. If you intend to have more than one foal in a stall or paddock, remember that an upset foal can sometimes become violent--so provide sufficient room for each to stay out of the other's way!
The period of time immediately pre- or post-weaning is not the time to vaccinate or de-worm your foal, get his hooves trimmed, or teach him to lead or tie. Not only is the foal likely to be distracted and thus very uncooperative, but any one of these demands could act as a stress multiplier, the last thing he needs. Ideally, vaccinations, de-worming, and basic halter breaking should have been done some time before weaning; if not, wait at least a couple of weeks after your foal has been weaned to undertake them.
Going Cold Turkey
The $64,000 question when it comes to weaning--is it best to suddenly and completely separate mare and foal, or is it kinder to part them gradually?
According to a doctoral study by Cynthia McCall, PhD, at Texas A&M University in the 1980s, it appears that foals which had fence-line contact with their dams during the first week of weaning showed greatly reduced signs of stress (vocalizations, fretfulness, and adrenal cortisol levels in the bloodstream) when compared to foals separated abruptly from their mothers. In fact, their behavioral and physiological responses to weaning weren't significantly different than those exhibited by foals which were not weaned at all. The fence line method allowed mares and foals to see, touch, and smell each other, but prevented nursing. McCall suspects that not only does this method of gradual weaning reduce foal anxiety, it also, in the end, might reduce the incidence of injuries. And because serum cortisol levels were not as elevated, the immune response in foals weaned this way might not be as severely compromised, meaning less risk of post-weaning illness. McCall notes, "I think the gradual approach is easier on everyone. After a while, the mares just wander off, and everyone's happy."
However, there are some physiological indications that gradual separation might just prolong the stress response in both mares and foals. The practice some farms use, of separating mares and foals during the day, and reuniting them at night (or vice versa), essentially jump-starts the stress cycle anew each morning, and might result in elevated cortisol levels--and all their associated damaging effects--that last for weeks. A single, final separation might be best for all concerned.
"There's no doubt that the weaning process is a painful one," says Karyn Malinowski, PhD, of Rutgers University, "but it's a short-lived stress if you do it right. I prefer to cut the umbilical cord, so to speak, and get it over with, on the theory that acute short-term stress is probably less harmful than prolonging it and creating 'chronic' stress. It's like quitting smoking, I think."
Indiana Thoroughbred breeder Julia Lord says that while she has experimented with various methods, "I don't really believe in the 'cold turkey' method. Usually, what I do is just casually move the mare to an adjoining pasture one day. They (mare and foal) can still see, touch, and smell each other; the foal just can't nurse. There is hardly any fuss at all. They usually hang around the dividing fence for a day or two, then go their own ways. The foals don't seem to mind that they can't get at Mom...and of course, the mares are usually just relieved!"
Another interesting finding from McCall's research at Texas A&M, in which she studied 21 Quarter Horse babies of four months of age, is that foals which were accustomed to a creep feed coped better with weaning stresses than did foals who didn't receive a creep feed prior to weaning. A creep-fed foal, she explains, often will gain more weight than one which only nurses, and that extra weight can help make any weight that he does lose during weaning less critical. In addition, because solid food is already a familiar routine to him, he'll have less trouble adapting to his new life. Foals in McCall's study which were not creep fed prior to weaning consumed considerably more feed post-weaning than did the foals accustomed to creep feed, and they also gained more weight; this likely reflected the foals' curiosity about the feed, but it carried with it the danger of accelerating the growth curve and predisposing those foals to orthopedic disorders (DOD).
This evidence strongly suggests that creep feeding your foals prior to weaning is a good idea. Most researchers now agree that providing a separate creep feed ration formulated for foals (usually made with milk protein, which has a better amino acid profile than plant-source proteins) is preferable to letting the foal just sample his dam's feed; apart from the differing nutritional requirements, the reality is that many mares are too possessive of their grain to let their babies sample much, and there is no way to calculate how much the foal consumes.
I Want To Be Alone
Conventional wisdom has it that foals weaned in groups suffer less stress than those weaned alone--the assumption being that misery loves company. A 1990 study by Malinowski and her associates, however, turned that practice on its ear when it demonstrated that foals weaned in pairs showed significantly more immunosuppression than those weaned singly.
In the study, which examined 20 Standardbred foals, blood samples taken at four, eight, 16, 24, 32, 40, and 48 hours post-weaning were examined for cortisol levels, which were shown to be elevated for an average of about 40 hours in both foals weaned singly and those in pairs. (Blood cortisol levels for the mares also were examined; they showed elevated cortisol for an average of 24 hours post-weaning.)
Blood samples taken prior to weaning, and at four and 28 hours post-weaning, also were examined for their lymphocyte proliferation response, an indicator of how well the immune system is reacting to challenges such as pathogens. (The lymphocyte proliferation response has been shown to be depressed in exercising horses, coinciding with rises in serum cortisol.) To everyone's surprise, the foals which were weaned in pairs showed a significantly lessened lymphocyte proliferation response when compared to foals in a control group (who were not weaned) and those weaned by themselves.
Malinowski explains the results like this: "The presence of another foal appears to have been intimidating for many new weanlings. One is usually dominant over the other, and the possibility of aggressive behavior can be very stressful. We found that paired weanlings vocalized less, and didn't do as much running around...but while that looks like it's less stressful, we suspect that the single foals suffered less immunosuppression because their repeated vocalizations, and their higher level of activity and aggressiveness, helped them to adapt to and release stress.
"On the other hand, the foals who were by themselves were sometimes really frantic. They were violent, throwing themselves around the walls of the stall and risking injury--and these were all valuable potential racehorses. The foals with a so-called 'buddy' were too intimidated to be so physical. Because of this, my own inclination would still be to recommend weaning with a companion. But an older gelding, a pony, or a donkey--one who is already familiar to the weanling and who is tolerant of his antics--might be preferable to the company of another foal."
Malinowski also notes that human contact can help relieve stress in a fretful foal. In her study, many of the foals weaned by themselves were so agitated that they had to remain under close surveillance--and human intervention was needed on more than one occasion. That contact and handling might have had a positive effect on the immune function of the singly weaned foals.
In fact, foals which are accustomed to being handled by humans are likely to suffer far less stress during the weaning process than those which have been left to run wild. If your presence is seen as comforting, rather than something else to be alarmed about, the foal might very well relax and begin to accept you as a substitute authority figure--which of course is exactly what you want to establish in your young horse's training. Consider yourself an active participant in the weaning process, even if it tears at your heartstrings at first to hear your foal's distress calls. The payoff will be a minimally painful weaning process, and with luck, a very soon well-adjusted weanling ready to progress towards equine adulthood.
1) He should be sufficiently socialized with other horses so that he will be able to behave himself in a herd without having mother there to intervene on his behalf.
2) He should be nutritionally independent--that is, he should not be deriving most of his nourishment from his dam's milk.
3) He should be emotionally independent.
In normal horses, any sort of major stress triggers the rapid release of adrenocorticotropic hormone (ACTH), the hormone that regulates cortisol secretion. When ACTH floods the horse's system, the immediate response is an increase in blood cortisol levels from the adrenal cortex (a pair of glands perched on top of the kidneys). This increased cortisol secretion continues until the stress is removed, until the animal adapts to the stressful situation, or until adrenal exhaustion occurs.
Why is cortisol considered to be such a good indicator of stress? For one thing, its presence is consistent with many different types of stress. Elevated cortisol levels have been demonstrated when horses are exercising; when they suffer fractures, colic, or hypoglycemia; and when they undergo anesthesia. Even unaccustomed confinement, or difficulties in getting a blood sample from a test horse, can cause the cortisol level to soar. Thus, most researchers consider blood cortisol levels to be a reliable way of measuring physiological stress in horses.
In contrast, some other indicators of stress do not appear to be affected by weaning. A study by R. M. Hoffman et al. at Virginia Tech University looked at levels of ascorbic acid in the blood of weanlings and found no changes pre- and post-weaning, despite the fact that blood levels of this chemical (also known as vitamin C) have been shown to be depleted in horses with other types of stresses, including long bone fractures, severe infections, and over-training.
Interestingly, cortisol levels in the bloodstream are affected by the horse's normal circadian rhythms. Maximum cortisol levels occur in the morning hours, so researchers prefer to analyze them when the levels are past their peak (often in early afternoon).
About the Author
Karen Briggs is the author of six books, including the recently updated Understanding Equine Nutrition as well as Understanding The Pony, both published by Eclipse Press. She's written a few thousand articles on subjects ranging from guttural pouch infections to how to compost your manure. She is also a Canadian certified riding coach, an equine nutritionist, and works in media relations for the harness racing industry. She lives with her band of off-the-track Thoroughbreds on a farm near Guelph, Ontario, and dabbles in eventing.
POLL: University Equine Hospitals