Three months ago, I asked about weaning a foal at five months on the Equine Wellness and Nutrition group on Facebook. (Read my post and the responses.) At the time, Scheherazade was not quite two months old. I was hoping to wean her at around five months. Well, now she’s going on six months old and not weaned. This is not because I’ve decided that it would hurt her to be weaned now. Rather, it’s for two reasons. (1) Fantazia was sore on her right fore so I couldn’t start conditioning her anyway. (2) Life got very hectic.
Fortunately, after reviewing the little research that has been done, I’ve come to the conclusion that–all things being equal– the best time to wean a foal is when it’s convenient. That said, there are a number of factors one should consider when weaning. They boil down to the health and job of the mare, the foal, and the owner/caretaker.
Above: Scheherazade at just over three months old. At this point she was eating a milk-based foal feed (Tribute Foal Foundation) mixed with Ultium Growth as well as alfalfa and Bermuda grass hay.
The well-being and “job” of the foal
Anecdotal evidence
My mother, who bred Morgan horses for years, settled on weaning foals when they were around four months old. She would keep the mare and foal side by side in corrals so that they could see and touch each other over the fence (but the foals couldn’t nurse). She said this was easier on both foal and mother. Waiting longer to wean, my mom says, led to greater emotional attachment. Removing the mare from the foal’s sight was too traumatic.
My mother tried different ages and methods. I have certainly heard breeders who took mares as far away from their foals as possible claim that out of sight was out of mind. Others claim there isn’t really any difference.
My experience separating attached older horses is that it is, if not out of sight out of mind, certainly out of sight, out of it being worth running up and down neighing. But older horses have learned that when a friend is stuck in the trailer and hauled away, it will do no good to scream about it. For foals, weaning is the first big separation.
Trends in weaning practices
My dates are approximate, since I am writing most of this from memory! Bear with me, and feel free to correct me in comments!
The 80s
When Fantazia finally settled, my mother lent me her “breeding bible,” Blessed are the Brood Mares, with the caution that some of it was out of date. Published in 1978 and written by M. Phyllis Lose, DVM, the book still offers a wealth of useful information. Lose recommends weaning around four months for two main reasons: it is easier on the mare and foals thrive when weaned and fed feeds designed to promote growth.
Dr. Lose worked on Thoroughbred farms where the goal was to produce big beautiful yearlings that would sell well at auction at 18 months. At the same time, in the horse show world, breeders wanted big, well-developed youngsters to show in hand (halter) and/or sell. Mixed horse feeds became popular. Foals were weaned early so they could eat without their mothers’ interference and grow faster.
This is entirely anecdotal (if I keep trying to cite this as if it were an academic paper I’ll never finish), but when I was a child, we mixed oats, barley, rice bran, Calf Manna, and Clovite. At some point, the newer editions of Purina’s Omolene appeared. Towards the end of the 80s, the first ration balancer (Triple Crown I believe) came on the scene.
Creep-feeders became more popular so that foals could be introduced to high protein and energy feeds. This would make weaning less traumatic and ensure foals got “enough” calories as their mothers’ milk became less nutritious. (By four months, milk provides less than 30% of the foals nutritional needs.)
The 90s
The trouble with trying to get big beautiful foals is that fast growth is not a good thing. Rapid growth resulting from feeding too much protein and energy can result in developmental orthopedic disease (DOD). (But note that the causes of DOD are many and complex.) After breeders had seen too many horses with stifle problems and upright pasterns and/or other effects of rapid growth beyond my knowledge, practices changed.
People began to worry about mineral balance rather than high protein and calorie diets for mares and foals. At the same time, horse people began moving away from early (4-5 months) to later (6+ months) weaning.
Jump to 2025
I had been paying more attention to discussions and articles about the best time to wean a foal ever since I decided to breed Fantazia. By the time Scheherazade was born, I had bought into the Zeitgeist and believed that weaning earlier than six months was detrimental to the foal’s mental and physical health. I believed this without any evidence I could readily put my hands on. Nutrition, I believed, was the primary issue. I was convinced that weaning earlier could adversely affect bone density.
When I asked about weaning earlier, I received an overwhelming about of feedback about why “early” weaning was bad. A few people argued that it wasn’t… and I will get to that.
Current views on the best time to wean a foal
The majority of the opinions offered me on Facebook seemed to be that weaning later was better. The rationale was:
- Bone development was better in foals weaned after at least six months.
- Foals were more emotionally traumatized when weaned early (less than six months, though some people advocated for weaning as late as possible).
- Mares were more emotionally traumatized with early (< 6 months) weaning.
On bone development
This one was the argument with which I was familiar. After getting feedback and seeing the extent of the acrimony based on little cited scientific evidence, I decided to do the research myself.
The claim that early vs. late weaning has a negative effect on bone development is based on Warren et al. (1998), which reports a study comparing seven foals weaned at 4.5 months with eight foals weaned at 6 months. (Red flag number 1: tiny sample size!) Wither height and bone density did not differ across the two groups. Foals weaned at 6 months had greater cannon bone circumference at that time (6 months) than those weaned earlier, but within three weeks there was no difference. The researchers concluded that there was no added benefit to weaning at 6 vs. 4.5 months when it came to bone development.
I could find no other studies that reported an advantage to later weaning. There is evidence that more exercise results in better bone development (e.g., Lepeule et al., 2011 [size of pasture and exercise]; Mouncey et al., 2025; Raub et al., 1989 [exercise after weaning];
On stress caused to foal
Many Facebook experts claimed that the primary reason to avoid early weaning was the stress it imposed on foals (and mares). This is something I had not worried too much about. If weaning is the most stressful thing a horse has to endure, it has had a good life, I thought. But! I decided to look into the scientific research.
There are more published papers on the effects of weaning time and method on the emotional well-being of foals. However, most studies suggest that the way foals were weaned mattered more than the timing.
Gradual or progressive weaning results in less stress to foals when compared to abrupt weaning (Apter & Householder, 1996; Mach et al., 2017). Abrupt weaning refers to leaving the mare and foal together all the time until weaning, when the two are completely separated. Gradual weaning can take the form of separating mare and foal for limited and progressively longer time frames and/or leaving the foals within sight or across the fence from dams.
Research provides evidence that foals suffer less stress when they are left with other foals or horses that are familiar to them (Erber et al., 2011; Henry et al., 2012).
However, other researchers report no effect of timing or method of weaning practices (Dwyer et al., 2024; Rogers et al., 2004)
Above: Scheherazade at four months and one week of age. I do not believe there is one best time to wean a foal, but I do believe I could have safely weaned her then.
From the mare’s point of view
The third argument put forward against early weaning was that it was hard on the mare. I really never bought his one. On the one hand, one of the biggest arguments for early weaning has always been that it’s easier on the mare. I did not buy that one either, because it seemed to be based on the fact that mares lose weight. That problem is easily solved by feeding mares adequately.
Anecdotal evidence of weaning stress
As for stress to mare, it seemed to be as a mother and observer of mares and foals, that weaning would not be necessarily unwelcome to the mare. My mother’s older broodmares had always seemed to welcome being separated. (But remember, my mother just put them on the other side of a fence, not out of sight and hearing.) I wasn’t at all worried about Fantazia’s mental health in this regards. Less than a week after Scheherazade was born, Fantazia exhibited a clear desire to be with River whether or not her baby came with her.
Horses don’t like being alone. They are social animals. As long as mares are placed with other familiar horses after weaning, there is no real reason why they should be stressed at being separated from their foals. This is especially true if weaning happens earlier rather than later, with less time for the mare-foal bond to solidify.
What about mare weight?
One of the arguments put forth in Blessed are the Brood Mares is that mares tend to lose more weight when the foals are left on longer. As mentioned above, this is easy to avoid: Feed the mare more. I found no scientific research on the effect of weaning time on mare condition.
Scholarly evidence
There have not been as many studies targeting mare welfare as there have been targeting outcomes for the foal. Falomo et al. (2020) compared the effects on mares (cortisol, appetite, and vocalization) of weaning at five months vs seven months and found no differences. However, there was a important potential confound. In the 5-month group, weaning was done two at a time and the mares were put out to pasture. In the 7-month group, all foals were weaned at once and the mares were left in stalls for two days.
Taking into consideration the mare’s job
If the mare was bred again after foaling, some consideration should be given to her downtime, as Lose mentioned in Blessed are the Brood Mares. This shouldn’t be a major issue, as natural weaning occurs around nine to ten months (Henry et al., 2020). If you wean at six months, the mare will have about five months to recover. (This supposes the mare was bred in the first heat after foaling.)
(It occurs to me that it’s a good thing–for breeders–that mares are not like women, who don’t tend to ovulate while lactating!)
Competition goals
My purpose in wanting to wean Scheherazade at five months was to condition Fantazia for a late season endurance ride. I am trying for decade award, and I wanted 2025 to count. (I realize that she can skip a year, but Fantazia is already 18 and arthritic.) Unfortunately, Fantazia starting limping under saddle on hard surfaces. I assumed it was a stone bruise, as she was barefoot. Turns out it was simply a very hard frog, but by the time I figured that out, I’d missed three weeks of riding.
Many horse owners may want to get their mares back into shape for shows or races. Part of the question I initially posed on Facebook was how to start conditioning my mare while she was still nursing. This is not only possible, but may also lessen the stress of weaning for foals. I noticed that Scheherazade became very relaxed with separation when I rode Fantazia frequently.
Mares may also be needed as lesson horses. One commenter on Facebook mentioned doing this successfully by leaving the babies tied in their stalls. Double benefit; foals get used to separation and practice tying!
The needs of the owner and/or caretaker
Given that there is little evidence that age at weaning affects the mental or physical health of foals or mares, it seems to me that the decision about timing should be based on the needs of the owner or caretaker. If the mare has another job, then she may need to be weaned sooner rather than later.
Other possible caregiver needs may be related to availability. Foals need supervision after weaning. I am going to wean Scheherazade over Thanksgiving break, when I will be able to keep an eye on her. (I work out of town Monday through Thursday.)
Yes, convenience is an important consideration. Owners or caretakers need to be present, and other obligations (work, shows, family) may take precedence. If owners have more than one foal, it may be easier to wean them together, so some foals may be weaned earlier. Pasture space might depend on factors such as needs of other horses and humans.
Above: A giant Scheherazade nursing on October 30th, nearly six months old. Fantazia is pretty much done. Scheherazade seems more attached now than she was two months ago.
Other factors that need to be taken into consideration
Although there doesn’t seem to be reliable evidence that time of weaning has any lasting effects on the physical or mental development of the foal, it is undeniably stressful. I am trying to avoid combining stress. For example, I have made sure that Scheherazade will not need to be vaccinated within two weeks fo weaning. I will not move any of the horses right before or after weaning. Weather shouldn’t be a problem, but I wouldn’t want to wean in the middle of a big storm.
The foal’s immediate future
When I was gathering information, I heard from many people who had bought foals. Many had been weaned around four months of age and shipped or picked up shortly thereafter. I heard of no harmful effects on the foals.
Anything else I am missing?
I started this blog post two months ago. Life got in the way of completing it when the information was fresh in my mind. I’ve surely forgotten a good deal of what I had to say originally! Please share any wisdom or experience that may be relevant. I would be happy to add it to this blog post!
Research on the effects of weaning practices
I carried out a quick literature review when I started this in August. Below is a list of the peer-reviewed papers I found, with brief summaries. At the end you can find a full reference section (After FAQ)
Apter & Householder, 1996: Gradual weaning and creep feeding prior to weaning reduce stress for foal.
Chatha et al. (2025): Studied Arabians, Thoroughbreds, and Percherons. Foals born in winter were less likely to survive. As for size, foals sheltered (in stalls vs turnout) over harsh conditions were larger. Foals weaned late (6 vs 3 months) were also larger. In Arabians, foals born to middle-aged mares (vs young and old) were taller.
Dwyer et al., 2024: meta-analysis; final sample N = 22 studies. The authors conclude that there is insufficient evidence on the long-term effects of weaning practices. Weaning is stressful for foals. However, there is no evidence that in the long term, timing or method of weaning affects emotional or physical development.
Erber et al., 2011: Presence of two familiar older mares lessened stress in foals (cortisol and behavioral signs). N= 17 foals in three groups. Group A (n = 6): all foals weaned simultaneously, left together with no older horses. Group B (N = 5) weaned simultaneously but left with 2 mares that had been in the group all along. In Group C (N = 6), two mares were taken out per day for three days. Most stress in Group A.
Brown Dougless (2003): Studied foals born in spring (and weaned in fall) vs. foals born in autumn (and weaked in spring). Those weaned in spring grew more post-weaning. Later, puberty was determined by body weight and season, not age.
Falomo et al., 2020 studied the effect on mares after weaning at 5 months (10 foals, 2 at a time, mares put out to paddock) vs 7 months (12 foals all together, mares in stalls for two days). Cortisol was used as a measure of stress, as well as eating and vocalization. . They found no difference in behavioral or endocrinological stress between mares in the two groups.
Henry et al., 2020: N = 16 mare/foal pairs left alone with minimal human interaction; “most” foals were weaned spontaneously at 9-10 months old. (They stopped nursing but were still bonded to mothers.)
Henry et al., 2012: Presence of familiar older horses lessened stress of weaning. (N = 32, but could not access full article).
Lepeule et al., 2011: Study of correlates of developmental orthopedic disorder in France (378 foals of different breeds). Results suggest that size of pasture (shouldn’t be too big), frequency of exercise/turnout (more the better), and nutrition associated with DOD, but not weaning.
Mach et al., 2017: Effect of weaning on foal gut microbiota; 34 foals were split into two groups, Abrupt (N = 16) vs. Progressive (N = 18) weaning. All were housed in two mare/foal pairs per enclosure. In the progressive group, foals experienced less stress as measured by cortisol, but weight and gut microbiota were not different between groups.
Mouncey et al., 2025: Study conducted with horses at Thoroughbred farms in the UK and Ireland suggests that greater turnout (time and pasture size) is associated with better racing outcomes (better odds of starting and greater prize money earned). Age at weaning was also positively associated with better outcomes (though the effect size was much smaller), but it could be confounded by turnout. In all cases, foals were separated from dams abruptly and kept in stalls after weaning.
Raub et al., 1989: Weanlings (N = 17) assigned to two groups, exercise (hot walker) vs. no exercise fpor 111 days. Those in the exercise group had greater cannon circumference and bone density; no differences in height or weight.
Rogers et al. (2004). New Zealand thoroughbreds. Sudden vs. progressive weaning. No effect of weaning methods or age on average daily weight gain. (It slowed in all foals). They conclude that body weight and season are more important than age and method. (Wean larger foals, not in winter)
Warren et al., 1998: In the short term, cannon bone circumference less for foals weaned at 4.5 months (N = 7) vs. 6 months (N = 8), but no diffferences a 203 days. Bone density was greater in the late weaning group before weaning. The authors note that the density of the left third metacarpal was greater than the right.
Frequently asked questions about weaning foals
What is the best age to wean a foal?
Does early weaning harm bone development?
What matters more — timing or method?
Can I wean early because the mare has a job?
When should I postpone weaning?
References
Click to show references
- Apter, R. C., & Householder, D. D. (1996). Weaning and creep feeding foals: Effects on stress. Journal of Equine Veterinary Science, 16(9), 365–369. https://www.sciencedirect.com/science/article/abs/pii/S0737080696802085
- Brown Dougless, C. (2003). Growth and puberty in Thoroughbred foals born in different seasons (Master’s thesis, Massey University). https://mro.massey.ac.nz/server/api/core/bitstreams/608d61ff-ce35-48c4-a720-13a6abe1c56d/content
- Chatha, B., et al. (2025). Foal survival and growth in different management and climatic conditions. Preventive Veterinary Medicine, 226, Article 106123. https://pmc.ncbi.nlm.nih.gov/articles/PMC11781635/
- Dwyer, R., et al. (2024). Weaning practices in horses: A systematic review and meta-analysis. Equine Veterinary Journal, advance online publication. https://beva.onlinelibrary.wiley.com/doi/10.1111/evj.14412
- Erber, R., Wulf, M., Rose-Meierhöfer, S., Scheuch, E., Mostl, E., & Aurich, C. (2011). Behavioral and physiological responses of young horses to different weaning protocols. Stress, 14(6), 622–634. https://www.tandfonline.com/doi/full/10.3109/10253890.2011.606855
- Falomo, M., et al. (2020). Effects of weaning age on behavioral and endocrine responses of mares. Journal of Equine Veterinary Science, 89, 103040. https://www.sciencedirect.com/science/article/abs/pii/S1558787819300437
- Henry, S., Briefer, S., Richard-Yris, M.-A., & Hausberger, M. (2012). Are 6-month-old foals affected by adult horse social support after weaning? Physiology & Behavior, 107(3), 384–392. https://www.sciencedirect.com/science/article/abs/pii/S0031938412000923
- Henry, S., Richard-Yris, M.-A., & Hausberger, M. (2020). Spontaneous weaning in domestic horses. Animals, 10(2), 361. https://www.mdpi.com/2076-2615/10/2/361
- Kentucky Equine Research. (n.d.). Developmental orthopedic disease in horses. https://ker.com/equinews/developmental-orthopedic-disease-horses/
- Lepeule, J., Bareille, N., Robert, C., & Valette, J.-P. (2011). Association of growth, nutrition, and exercise with osteochondrosis in French foals. Preventive Veterinary Medicine, 101(1–2), 28–34. https://www.academia.edu/download/97795237/j.prevetmed.2011.05.00920230125-1-e3beyj.pdf
- Lose, M. P. (1978). Blessed are the brood mares. Lippincott.
- Mach, N., et al. (2017). The effects of weaning methods on stress and gut microbiota of foals. Frontiers in Physiology, 8, 535. https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2017.00535/full
- Mouncey, P., et al. (2025). Early-life management factors associated with later racing performance in Thoroughbreds. Equine Veterinary Journal, advance online publication. https://beva.onlinelibrary.wiley.com/doi/10.1111/evj.70084
- Raub, R. H., Jackson, S. G., & Baker, J. P. (1989). The effect of exercise on bone development in weanling horses. Journal of Animal Science, 67(10), 2502–2508. https://pubmed.ncbi.nlm.nih.gov/2808156/
- Rogers, C. W., Firth, E. C., Perkins, N. R., Anderson, B. H., & Gronqvist, G. (2004). The effect of two different weaning procedures on the growth of pasture-reared Thoroughbred foals in New Zealand. New Zealand Veterinary Journal, 52(6), 362–367. https://www.researchgate.net/publication/7966917_The_effect_of_two_different_weaning_procedures_on_the_growth_of_pasture-reared_Thoroughbred_foals_in_New_Zealand
- Warren, L. K., Lawrence, L. M., Parker, A. J., & Kline, K. H. (1998). The influence of weaning age on foal growth and bone development. Journal of Equine Veterinary Science, 18(5), 335–342. https://www.sciencedirect.com/science/article/abs/pii/S0737080698805480