Should I Rug My Horse?
What Is The Horse’s Thermoneutral Zone?
How To Determine The Temperature Of Your Horse?
How Rugging Affects Your Horse’s Coat?
How Do Horse’s Cool Their Body?
Health Issues From Overrugging?
SHOULD I RUG MY HORSE?
As winter arrives, we feel the cold and in some instances the thicker rug is brought out for our beloved horses to keep warm. But could this be affecting their health, in particular their metabolic rate?
We can determine the effect of rugging horses by understanding their physiology.
WHAT IS THE HORSE’S THERMONEUTRAL ZONE?
This is the temperature range where body temperature is maintained with little to no energy expenditure.
A horse only feels cold when the weather creates temperatures below approx. 5°C and only feels hot when it reaches above approx. 25°C. This is the range of their Thermoneutral Zone.
This thermoregulation is maintained by the heat generated from the fermentation of fibre within the hindgut and the digestion of food inside the many cells of the body. The horse’s core temperature is kept at approx. 38°C, this is tightly regulated by their body.
Compare this to humans; our Thermoneutral Zone is very narrow approx. between 25°C and 30°C. Therefore when we feel cold outside, horses still feel comfortable, which is why we shouldn’t make a decision of when to rug by how cold we are.
Additionally feeling your horse’s face, ears or legs is a poor indicator of warmth.
HOW TO DETERMINE THE TEMPERATURE OF YOUR HORSE?
The best place is to position your hand inside the rug behind the withers. If damp, it indicates sweating and is probably too warm, so remove the rug. If cold (rare cases) consider an extra rug.
The physiology of the horse is designed to cope with cool temperatures. The horse will increase their metabolic rate when temperatures become cooler. This can be seen with horses dropping weight in winter if calorie needs are not met. If the horse has unlimited access to pasture or grassy hay, then this constant digestion will ensure weight is maintained and warmth is produced, they will self regulate the amount they ingest. In some cases additional calories can be added.
HOW RUGGING AFFECTS YOUR HORSE’S COAT?
The fur coat of a horse is excellent at preventing body heat loss and holds heat much better than we do. If a horse is too heavily rugged, their metabolic rate slows as they do not need to expel energy to keep warm, this can lead to weight gain in the form of fat from the excess unburnt calories.
Thermoregulation enables the ability of a small muscle associated with every hair follicle to pull the hairs to a standing “puffed-up” position (piloerection). This is controlled by the nervous system when temperature changes are detected.
Rugging inhibits the function of the hair follicles from doing their job. In some circumstances a rugged horse is actually colder than an un-rugged horse if it is a badly fitting thin rug that flattens the hair and reduces the movement of the horse without providing any real warmth.
“Using rugs on horses in summer can be a welfare issue. Rugs do not keep horses cool. A horse naturally has a sleek coat which reflects the sun and a horse will seek shade when they are hot as a natural response. All large bodied animals, such as horses, take longer to cool down (and warm up) than smaller bodied animals. Rugs prevent any cooling breeze from cooling the body. Horses are one of the few animals that rely on sweating to cool down and rugs impede this process (by preventing air from passing over the body, evaporating the sweat and cooling the body).” stated by The RSPCA and Jane Myers (MSc Equine)
HOW DO HORSE’S COOL THEIR BODY?
- The horse lowers its metabolism and will eat less so less internal heat is produced.
- Seeking shelter from direct sunlight.
- Sweating, which increases the respiratory rate as a result of dilated blood vessels.
HEALTH ISSUES FROM OVERRUGGING?
If a rugged horse is sweating and overheats, it can lead to many health issues:
- Thyroid gland function can be reduced which leads to a horse unable to control its own body temperature
- Damage to body cells and tissues
- Can affect Immune system function
- Decrease growth and healing
- Electrolyte level imbalances
- Issues with sperm, embryo development and lactation in breeding horses
- Promotes obesity or other metabolic issues, in particular if grain based feeds are fed for calories due to the cold weather
WHEN SHOULD YOU RUG A HORSE?
- When a horse that is severely underweight & malnourished, this is because the rugging will slow down their metabolic rate and extra calories will help add condition.
- When a horse who can no longer self-regulate their body temperature usually older than 20 years of age.
- An itchy horse, protecting from biting insects who come out at these times, we recommend adding a quality source of Omega 3 to their feed to promote anti-inflammatory properties and strengthen the immune system. Treating the cause rather than symptoms.
- Protecting clean coats for the lead up to shows – best to leave unrugged for a few hours during the day and rug at night.
In summary, having an understanding of the horses physiology will allow horse owners to make a more educated decision whether to rug their horse.
In general, most horses in a group setting with access to adequate shelter and plenty of roughage (pasture or grassy hay) do not need any rugging.
On the other hand, elderly, sick, clipped or more sensitive horses can be assessed differently.
Management of the environment and proper nutrition are the main factors when choosing to rug or not and should be made in the best interest of the horse.
Please contact us if you need guidance with nutrition for the winter season.
Written by Bryan Meggitt (BMedSc. PGCrtMedSc.)
Biochemist / Senior Scientist and Co-founder of CEN Horse Nutrition
Bryan is a scientist and equine nutrition educator through the nutrition principles of Dr Juliet Getty and Dr Eleanor Kellon.
Bryan is passionate about improving equine health through natural nutrition according to science.