It's always great when research is applicable right away. This is certainly the case when it comes to investigating the best weaning practices for mares and foals. The main goal of most breeders is to minimize stress and many have their preferred methods based on their mares, facilities, schedule, and past experiences, but it never hurts to see what's out there and join the conversation!
Gradual vs. Abrupt
Do you wean your foals gradually over a period of time or prefer immediate separation? Research tends to back a gradual approach, separating mares from their foals for increments of time each day*. A good compromise between the two (which also works well with varying ages and space requirements) is gradual group weaning. Removing a few mares at a time, leaving their foals in the herd with the remaining mares appears to reduce levels of insecurity and keeps foals from feeding off the panic of other foals, escalating their response. Of course, for this to work, the mares left behind need to be tolerant of other foals as they will likely be approached. Once all the mares have been removed, consider leaving another adult horse with your group of weanlings to act as a "babysitter", providing direction and security for the herd.
During times of stress, cortisol is produced, effectively decreasing the body's inflammatory and immune responses. To lessen the risk of respiratory or gastrointestinal illnesses' it is important to make sure your foal is in optimal health before you begin weaning. It is also important to tighten up your biosecurity practices in order to minimize the introduction of new pathogens to newly weaned and now vulnerable foals.
The age of your foal is often one of your first thoughts when it comes to weaning. It is common practice to avoid weaning foals before 4 months of age in order to mitigate some of the other areas that make foals vulnerable. But how old is too old? A 2019 study found that 6 month old foals displayed fewer signs of stress when compared to 7 and 8 month of foals, indicating that 6 months of age is the optimal time to wean**. Foals around this age are likely already seeking independence and have begun to self wean.
With most foals being ready to wean late summer, it is wise to take climate and weather into account. Weaning is stressful and can often distract foals from maintaining sufficient fluid intake, seeking proper shelter from the elements, and conserving energy. Plan ahead and make sure you aren't scheduling to wean on the hottest days of the year!
It doesn't take long for foals to dehydrate. Make sure you catch them drinking post-weaning.
It's always best to leave foals where they are safest, this is usually an area they are most familiar with. Some breeders prefer to keep foals in stalls to monitor them closely but if so, it is best to stall them individually and have them habituated to a stall ahead of time. Keeping foals stalled in pairs within earshot of their dams is noted as one of the more stressful ways of weaning***. Depending on your facilities, another option is to remove the mares to a location on the farm where they cannot be seen or heard and leave the foals in their pasture. The less things you change about their environment during this time, the better!
If you're weaning around the recommended 6 months of age, most mares will have already has a significant drop in milk production indicating that at this point, foals will be nursing to satisfy behavioural needs rather than nutritional. As long as your foals have a healthy appetite for their balanced grain ration and forage prior to weaning, they should resume normal eating habits after an understandable post-weaning dip. Monitor your foals' body condition and feeding time behaviour. Some foals may be less bold without their mothers at their side and be pushed out by their dominant friends.
Minimizing stress during weaning is in the best interest of your mares, foals, and you. Consider all factors when it comes time to wean and come up with the best plan to keep your foals safe and on track for life as a weanling!
* Lansade et al. 2018. Progressive habituation to separation alleviates the negative effects of weaning in the mother and foal. Psychoneuroendocrinology. Vol 97. pp 59-68.
**HaiXai et al. 2019. Effect of different weaning age on behaviour of British Thoroughbred foals. Southwest China Journal of Agricultural Sciences. Vol 32 No. 3 pp. 665-672.
***Rice. D. 2019. What's new with weaning horses? The Horse.