As the weather cools at this time of year and we start to feel the cold, there is an often misplaced perception among many horse owners that their animal must also be getting cold and will need to be rugged. But before dashing out to cover our horses up, it's worth considering if this is actually the case? Or are we making them “too hot to trot”?
Over-rugging can be problematic for horse comfort and wellbeing. It is important to know how to strike the right balance for our climate and the needs of your individual horse.
Our New Zealand climate
New Zealand has a diverse climate. While it ranges from subtropical in the far north to temperate in the south, it also includes extremes and microclimates in the coastal and mountainous regions. Our country’s weather patterns are heavily influenced by our maritime location and mountainous terrain, resulting in variable conditions throughout the year. Winters can be chilly – especially in the southern regions – but much of the country enjoys mild temperatures for a significant portion of the year.
We are great at planning our own outfits for NZ’s variable weather, but it can be tricky to interpret how our horses experience the same conditions. It is important to remember, horses don’t feel the cold in the same way that we do. The temperature range that a healthy adult horse will feel comfortable in, where they can regulate their own body temperature is between 5°C and 25°C.
Research suggests that horses only begin feeling the cold below 5°C . That’s well below when we throw on a jacket. Horses are extremely efficient at regulating their body temperature, which they do by eating more forage, seeking shelter, reducing the blood flow to the limbs (to reduce heat loss), increased movement and shivering. As winter approaches, a horse will naturally grow their coat in response to the shortening day length. Therefore, although well intentioned, putting a rug on when the horse’s body has already started prepping for winter, may be negative for their health and wellbeing.
The risks associated with over-rugging:
One of the primary concerns with rugging is overheating, particularly during periods of mild or fluctuating weather or when horses are highly active. Under normal conditions, horses will actively respond to cold or hot temperatures by seeking shelter or shade. Unfortunately, the horse cannot escape from a rug (easily) and so cannot regulate their own temperature.
Sadly, there are some horse owners who choose to keep a rug on their horse 24/7. When horses are constantly covered, their skin may become sweaty and damp, creating an ideal environment for skin issues such as dermatitis and fungal infections. In addition, they will miss out on the benefits of sunlight on a large part of their body and research shows that this can affect the level of the Vitamin D the horse needs for remaining healthy.
Rugs aren’t a natural attire for a horse. They don’t always fit well and can be too tight or too loose. They can also impede the horse’s free movement and reduce some of the benefits horses get from natural behaviours such as rolling and grooming each other. In addition, when the weather is nasty, rugs sometimes leak and can become heavy when wet and muddy. They need to be regularly checked for comfort and dryness, and a spare rug should be available for these circumstances.
So - when is a rug needed?
First and foremost, not all horses require the same level of protection. Factors such as age, breed, body condition, and health status, coupled with the environmental conditions, and access to feed and shelter, all influence a horse’s tolerance to cold temperatures. Older horses or those with underlying health issues may benefit from additional insulation, whereas younger, healthier horses may do well with little to no coverage. If a horse has little body fat (a fat score of less than two on a scale of 0 to 5), a rug will be needed if temperatures drop. The horse’s legs, ears or face are not the best areas to indicate how cold they are, instead their neck, withers and body temperature should be assessed.
There is no strict rule for NZ’s conditions. 10°C is a good benchmark for when rugging could be considered (but not necessarily implemented for the reasons given earlier). For instance, research shows that horses with a thick winter coat, can comfortably tolerate temperatures well below freezing (0°C) without the need for rugs, especially if they have access to shelter from the elements and good quality feed. The latter supports the horse by providing them with adequate energy to stay warm. Conversely, horses that have been clipped, or those moving from warmer too cooler climates and therefore not acclimated nor equipped with a thick coat, may benefit from rugging to maintain comfort and prevent chilling.
After taking into account your horse’s individual needs, the next step is to consider the weather conditions they will encounter. Autumn brings cooler nights followed by warm days. Therefore, a rug might be appropriate at night, but should be removed during the day. Autumn daytime temperatures can soar to nearly 20°C in some areas and if it's not possible to remove the night rug, the horse will be too hot. Even a light cotton rug challenges a horse’s ability to thermoregulate as temperatures rise; one Australian study showed that whilst the cotton rugs intended to reduce fly irritation might serve that purpose, they also resulted in heat stress in horses when the temperatures were above 25°C.
Letting horses decide
Researchers in one creative study taught horses to ‘vote with their muzzles’; the horses learned to touch symbols which represented whether they wanted their rug on or off. ¹ Interestingly, no horse preferred a rug on when experiencing temperatures above 20°C. Even at 10°C the horses showed a preference for ‘no rug’, however this was dependent on other weather conditions, such as wind and rain together (opted for the rug) or more sun (opted against the rug). In addition, older horses were more likely to choose a rug on when temperatures reduced. While we can’t all enrol our horse in a preference study, we can take note of the research related to horse preferences and observe what our horses are doing. Are they seeking shade, even when we feel comfortable? Is their coat hot or damp under their rug? Are they breathing more than they would on a cool day? (An adult horse’s normal resting respiratory rate is around 8 – 16 breaths a minute). If you notice any of these signs, take note of the weather, and try removing the rug when conditions are similar.
Concluding thoughts
Reevaluating our approach to horse rugging in New Zealand demands a nuanced understanding of our diverse climate and the individual needs of our equine companions. The risks associated with over-rugging emphasise the importance of striking the right balance between protection and allowing horses to regulate their body temperature naturally.
With temperatures varying across the islands and seasons, there's no one-size-fits-all rule for rugging horses. Instead, horse owners must consider factors such as coat thickness, health status, age of horse and prevailing weather conditions to make informed decisions. By staying attentive to their horses' cues and consulting with equine professionals, we can ensure the well-being and comfort of our equine partners while navigating the complexities of New Zealand's climate.
If you have specific questions about your horse’s health, speak to your vet.
1 - Study: Horses can Communicate Blanketing Preferences – The Horse