Do Premarin mares have good welfare?
A commentary on a post by Dr. Jen Gunter
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I recently saw a post titled “Premarin is Extracted from Horse Urine, and that's Okay” circulate on social media. It is written by Dr. Jen Gunter OB/GYN, and reads a bit like a Pfizer ad.
Premarin is a hormone treatment derived from pregnant mare urine (PMU). PMU production has been criticized for decades due to concerns about the living conditions of the mares on the farms and the fates of the surplus foals1. (I am old enough to remember the debate around this in the early 00s).
Dr. Gunter, who is a medical doctor, defends the production of PMU and claims it is produced under good welfare conditions. I strongly disagree. While I normally refrain from critiquing the opinions of private individuals, Dr. Gunter is well-respected and has wide influence, so I feel compelled to address some of the misconceptions.
Dr. Gunter says in her own bio that “it would be hard to find someone who knows more about the vulva and vagina” than her. Well, it would be hard to find someone who knows more about horse behaviour and welfare than me, so let’s dive in!
Premarin mares do not have good welfare
There are essentially three problems with Dr. Gunter’s post:
It is based on information from a biased source: The North American Equine Ranching Information Council (NAERIC) which represents the farmers who produce PMU.
It is a PR piece meant to make PMU farming look as good as possible. NAERIC describe industry best practice, not the reality on the ground.
Industry best practice is not the same as good welfare. Many of the practices are awful (and some would be banned in other countries).
But let’s go through it in more detail.
First, it is important to understand that NAERIC is an industry body that represents the farmers who are contracted by Pfizer to collect the urine. Of course they will paint a rosy picture of their own jobs when asked about the welfare of their horses. After more than a decade of working in politics and public affairs, I recognize lobbying when I see it. And while lobbying is not necessarily a bad thing - it’s just their job - we should be aware of it and not take their words at face value.
Unfortunately, that is what Dr. Gunter does, which means that the information she provides is biased - and in some cases even flawed.
Below, I comment on some of the more problematic statements from her post and provide additional context from industry regulations, such as The Code of Practice for the Care and Handling of Horses on PMU Ranches, and equine behaviour research.
Dr. Gunter writes: “During summer, which is breeding season, a group of mares are in a pasture with one stallion, and they breed naturally. The foal stays with its mother during this time (when she is pregnant again), and weaning is not allowed before four months.”
This is not entirely accurate. The industry Code of Practice says the following:
In fairness, whether the foals are weaned at three or four months doesn’t really matter; either way, they are too young. At that age they are still completely dependent on their mothers. Forced separation of young foals is a highly traumatic event and not in any way compatible with good welfare.
Under natural conditions, foals will generally nurse for food until they are about 8-10 months, but may nurse for comfort until they are much older, because nursing is not just about nutrients but equally about the social bond between mother and offspring. And that bond is strong: a recent study2, for example, found that foals separated from their mothers at seven months remembered them many months later. (I have written about it in a previous post.)
There have been many studies on the short- and long-term effects of weaning on foals, and the general consensus among ethologists is that artificial weaning is a highly stressful event3. Foals should not be weaned before c. 7-8 months, and any weaning should happen gradually to avoid causing emotional distress to both mare and foal.
Weaning practices at PMU farms ignore scientific evidence and cause stress and emotional suffering to both mares and foals - hardly an example of good welfare.
(Additionally, I question the industry’s motivation for early weaning. The Code of Practice says that it is necessary to “facilitate handling and training” of the foals and to “allow the mare to regain body condition”. This is categorically not true. There are plenty of breeders who are capable of handling and training their foals while allowing them to remain with their mothers for longer. And if a mare loses condition, it simply means she has not been given enough food. I rather suspect that the purpose of early weaning is to get rid of the foals early to avoid the cost of keeping them, and to exploit the mares with a quicker turnover.)
Dr. Gunter writes: “Each horse has a stall wide enough to turn around and lie down during urine collection season.”
The mares seem to be mainly confined to tie stalls (see screenshot from NAERIC website below). In theory, they may be able to turn around, but in practice they can’t because they are, well, tied up.
Based on the below photo, it doesn’t even look like they can comfortably lie down on their side, a prerequisite for a normal sleep cycle.
Dr. Gunter writes: “Horse behavior inside the stall during the winter while hooked up to the collection system has been evaluated and found to be normal.”
This seems to be based on an unpublished industry-commissioned study from 1998. I haven’t been able to find the ethogram or the data from the study, so I can’t say much about the results. What I can say with great certainty is that being tied to a wall for months is not ‘normal’ behaviour for any horse.
In the 25 years since the industry study above, there have been many other studies that have looked at horse behaviour under various conditions, such as time budgets, social behaviours, choice preferences, and so on. They have led to the formulation of the so-called ‘3 Fs’ model of good horse welfare: Friends, Forage, and Freedom4.
Essentially, horses need to live in stable social groups, have access to forage around the clock, and adequate space to move as much as they want to. These are behavioural needs, not wants - the 3Fs are non-negotiable from a welfare perspective.
If we want to know whether mares at PMU farms have good welfare or not, we need to see how the farms score on the 3Fs. In terms of forage, it may be possible to provide the mares with free-choice forage in a tie stall.
What about friends and freedom?
Dr. Gunter writes: “The horses are unhooked and moved into paddocks to exercise and socialize for at least an hour every two weeks, but some ranchers may take the horses outside more, and some have indoor arenas, which may be an option if the weather is very bad.”
The Code of Practice states the following:
One hour of turnout every two weeks (!) in a small area (1000 square feet is roughly 10x10 meters) is nowhere near enough to cover the basic needs for socialisation and movement that every horse has. (Yes, every horse.)
Horses have evolved to live in stable social groups on large home ranges which can be 50 square kilometres in size. Domestic horses will frequently move 10-20 kilometres per day when given adequate space to do so. Importantly, that movement is evenly distributed over day and night.
There are plenty of studies that have looked at time budgets under different conditions. Below is a recent example that shows how domestic horses portion out their movement throughout the day. This is based on data from the Swedish Brösarp project from 2022, which featured Warmblood youngsters.
Taken together, it becomes pretty clear that around-the-clock confinement to a tie stall will not provide adequate freedom to move, and is consequently not good welfare. Restricted movement increases the risk of colic and respiratory issues, leads to decreased bone density, can worsen osteoarthritis, cause emotional distress which manifests as stereotypical behaviours, and so on.
It is true that pregnant mares generally tend to move less than other horses, especially towards the end of their pregnancy, but that does not mean they should not be provided with the opportunity to move if and when they need to. There is a big difference between chosing to move less and being forced to not move at all.
And regardless of their movement needs they will have socialisation needs5. Being able to interact with other horses is fundamental for their welfare: studies have shown that horses even chose the company of other horses over food and shelter.
Being tied up next to each other is not enough to provide them with the social relationships they need. Horses have evolved over millions of years to lead rich and complex social lives6. They are selective about their social groups and form close personal bonds with each other that can last for a lifetime.
These bonds are created and maintained through friendly interactions such as eating together, resting together, and grooming each other7. Most ethologists will agree that it is not enough for a horse to have visual contact with other horses - they should be able to touch each other, too.
Dr. Gunter writes: “Vets visit three times a year, and the horses must all be vaccinated, have the right hoof care and feed, have computerized medical records, and have no contact with poultry. With privately owned horses, only 48% see a vet once or more a year, and there is no requirement for hoof care, medical care, feed quality, or exercise.”
On a side note: this is incorrect. Canadian law stipulates among other things that it is a criminal offence to fail to provide adequate care for an animal, which covers things such as appropriate hoof care and veterinary treatments.
Welfare is about more than just coping
So how did we end up here?
Dr. Gunter references The American Veterinary Medical Association and the American Association of Equine Practitioners, which state that PMU farming, when done according to the Code of Practice, “should not result in abuse, neglect, or inhumane treatment of horses”.
And this, I believe, is the core of the problem. Because not abusing, neglecting or treating horses inhumanely is not the same as providing them with good welfare. By now, we should have higher standards than simply not hurting animals physically.
Classically, animal welfare has gone beyond physical injury and looked at evidence of stress through physiological and behavioural parameters such as increases in heart rate, cortisol levels, or the prevalence of stereotypical behaviours. But this approach is also inadequate, because it only flags individuals who are already struggling to cope.
Welfare should not be about coping, it should be about thriving. Animal welfare research is increasingly moving away from simply avoiding negative experiences to promoting positive experiences8, and advances in ethology highlight the importance of taking species-specific behavioural needs into account when evaluating welfare.
Instead of a retrospective approach where we subject animals to suboptimal living conditions and then try to identify individuals that are suffering, we need to adopt a more proactive approach where we promote a good life for every individual from the start, by designing management systems that take species-specific needs into account.
Sadly, the horses in the PMU industry are being denied their basic needs - Friends, Forage, and Freedom - and so they do not have good welfare.
This is the bottom line.
(A final note: I am aware that many practices such as long-term confinement, social deprivation, and early weaning are not exclusive to PMU farms, but are common in the wider equestrian industry. But just because something is common does not mean it is good, and it is important that we fight for horses’ rights to live good lives regardless of their use.)
A note on the references below: they represent a tiny selection of studies on the topics covered here. The body of research to support the behavioural needs of horses is vast.
In this post, I don’t comment on the fate of the foals because I personally don’t know what happens to them. However, there are reputable Canadian horse welfare advocates who claim to have seen PMU foals sold to slaughter at auctions, and I have no reason to doubt their eye witness accounts.
Lansade L, Lévy F, Parias C, Reigner F, Górecka-Bruzda A. 2022. Weaned horses, especially females, still prefer their dam after five months of separation. Animal 16(10):100636.
https://doi.org/10.1016/j.animal.2022.100636
Henry S, Sigurjónsdóttir H, Klapper A, Joubert J, Montier G, Hausberger M. 2020. Domestic Foal Weaning: Need for Re-Thinking Breeding Practices? Animals, 10(2):361. https://doi.org/10.3390/ani10020361
Krueger K, Esch L, Farmer K, Marr I. 2021. Basic Needs in Horses? A Literature Review. Animals 11(6):1798.
http://doi.org/10.3390/ani11061798
Van Dierendonck MC, Sigurjónsdóttir H, Colenbrander B, Thorhallsdóttir AG. 2004. Differences in social behaviour between late pregnant, post-partum and barren mares in a herd of Icelandic horses. Applied Animal Behaviour Science 89(3-4):283-297.
https://doi.org/10.1016/j.applanim.2004.06.010
Van Dierendonck, MC. 2006. The importance of social relationships in horses. Doctoral Dissertation. Utrecht University, Faculty of Veterinary Medicine.
Mendonca RS, Pinto O, Inoue S, Ringhofer M, Godinho R, Hirata S. 2021. Social determinants of affiliation and cohesion in a population of feral horses. Applied Animal Behaviour Science 245:105496.
https://doi.org/10.1016/j.applanim.2021.105496
Reimert LE, Webb MA, van Marwijk MA, Bolhuis JE. 2023. Review: Towards an integrated concept of animal welfare. Animal 17(4):100838.
https://doi.org/10.1016/j.animal.2023.100838
Thank you for this very important and informative article on PMU mares. As far as I know there is an alternative to (ab)using mares to produce these hormones. The university of Zurich Switzerland is working on developing an invitro production of pregnant mare serum gonadotropin. Hopefully it will become available soon and end the inhumane suffering for all these mares and foals worldwide.
Holy crap. I have never heard of this practice in South Africa. Beyond awful and so typical.of big pharma.