Snow Hill, Maryland

Blanketing Pros and Cons from Scientific research

Does Cold Cause Colic?

At a recent wedding, a guest asked, “Do you love the horses that are wearing blankets more?”

We laughed, and explained that some of our clients blanket their horses because they love them and some do not blanket often because they love them :) These are actually common questions from couples who come to Castle Farm in the winter, and a controversy hotly debated among experienced horsemen. Some of our horses are blanketed all winter with frequent changes in the weight of the blanket and even adding double blanket layers at times, and some are only blanketed when the real feel is under 20 degrees and some are not ever blanketed. We realized that many times we do things because they have always been done that way, because we were taught to do them that way or because of an emotional reaction and a personification of human emotion onto our animals. Just because we are cold outside does not mean that our horses are cold too. The most commonly debated issues around this topic are:

Do horses need blankets?

Are blankets necessary for a horse to feel warm?

Does cold weather cause colic?

These questions caused some controversy even within our own barn and at Castle Farm, we like to stay up to date and always perform best practices so we decided to look at the current science with an open mind. We did a veterinarian medicine literature review of all of the articles published within the last 5 years on equine thermoregulation, causes of colic, and blanketing of horses and we found that there is still no consensus but thought we would share our findings with our friends of Castle Farm.

Some people believe that colic is caused by cold weather but that is really just an association, not causation. Colic strikes fear in the heart of all horse owners since it is responsible for more horse deaths than any other illness, except old age.

The word colic though, literally just means stomach ache. The abdominal pain can be caused by impaction blockage, twisting or displacement of the intestines, or blockage from a tumor in the GI tract. The most common reason is impaction from constipation from inadequate water intake or inadequate exercise. Horses drink on average 12 gallons of water daily. Horses are grazing animals and meant to walk miles a day foraging. The reason that colic occurs more often in cold weather is due ironically to the change in their water intake, and exercise level from being brought into stalls more in the cold weather and due to dehydration and resulting impaction from frozen water troughs not from physically being cold.

Colic can result from overfeeding grain, keeping your horse inside a stall more, rather than turned out and not adjusting the diet to compensate for the altered sedentary lifestyle of a stall and the disruption and sudden changes in diet and exercise resulting from alternating a warm stall and cold outside temperatures. Many old horsemen strongly believe that leaving horses turned out 24/7 even in extreme weather decreases colic as long as they have an ample water supply.

Some horse owners blanket because they believe that blanketing prevents colic, others blanket to make their horses more comfortable. Show horses are sometimes clipped and when the hair is removed, blanketing becomes necessary because they are left defenseless, so this discussion is only relevant to horses with normal unaltered coat development. There is very little actual data on blanketing horses. Some horsemen never blanket and some only use blankets on horses that are very old or young or clipped, others vary the weight of the blanket depending on the weather and change blankets several times daily. A study in J Equine Vet Sci in June 2022 surveyed 1450 horse owners within the USA on blanketing practices and “found 54% of respondents (n = 790) reported blanketing the majority of their horses in the winter. The most frequently selected reason respondents chose to blanket horses was exposure to precipitation (78%). Out of the respondents who did not blanket the majority of their horses (n = 660), the primary reason for not blanketing was access to shelter (50%)”.

Horses are much more cold hardy than humans and can tolerate from -40 degrees F to 104 F (Vet Clin North Am Equine Pract 1990). The main issue is not shelter, but water and energy production in the horse’s gut. Their nutrient requirements to stay warm are most influenced by feeding good quality hay. Use of grain and fat in the diet produce very little heat compared to fibrous feeds such as hay and grass which is why we choose Tribute Kalm EZ grain due to its 20% fiber content. Wind or precipitation necessitates shelter protection to minimize chilling in cold weather. Research on the effects of blanketing on horse welfare is scarce but results indicate that blanketing and clipping may not be necessary from the horse’s perspective and can interfere with the horse’s thermoregulatory capacities.

Horses have hair that stands up and provides insulation. The hair stands up ( piloerection ) and that increases their hair depth and traps a layer of air next to their body creating a layer of insulation that is more efficient than most blankets. When it’s wet, the hair lays flat but their skin can still stay dry because they have so much natural oil in their hair coat that it actually forms a barrier to keep their skin dry. When horses are outside 24/7 and not blanketed, it’s important not to bathe them in the winter or the oil gets removed and blanketing becomes necessary. Blanketing early in the season prevents full hair growth and development for the season and makes horses colder, they flatten the hair preventing the air trapping that results in natural heat barrier and decrease the air circulation necessary for a healthy coat. If blankets are not 100% waterproof and they leak, they increase skin fungal infections by trapping water under the blanket and make the horses much colder since they now have wet skin and can not use piloerection to stay warm.

When these horses are brought into a stall to stay warm, they also have their movement and exercise limited. Horses in nature, forage 24 hours a day and are therefore walking miles a day. They produce heat in their gut as they move and ferment and digest hay and roughage which generates heat that helps maintain their body temperature. Bringing horses in and out of a warm stall into the cold is actually harder on their body than leaving them out in cold weather as long as they have shelter and access to clean unfrozen water.

Of course all of the companies that sell blankets have a different perspective 🙂

There is limited data and no clear answer. We will continue to only blanket in very extreme conditions, continue to let our horses graze in large pastures unless the weather is extreme and I am happy to now have an excuse not to bathe them in the winter! We will continue to let our boarders make blanketing decisions for their own horses but we will encourage more turnout and less blanketing. Our goal at Castle Farm is happy healthy horses and clients. To answer the original question, “Just like our children, we love them all the same”.

bride and groom walking in a horse pasture

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