This question can be a continual nightmare for owners/carers and guardians of horses. I am often asked for my opinion on rugging and the truth is, this isn’t an easy question to answer. There are so many factors to consider when deciding whether an individual horse requires a rug or not, but here are some interesting facts and points to consider when deciding for your own horses.
Horses are pretty unique in their adaptability to their environment, they can survive in a wide range of environments, from desert to artic conditions, and as a result they have some impressive thermoregulatory systems.
Between 5C and 25C they are capable of self regulating their temperature through metabolic processes. Outside of this temperature range they can utilise a vast array of behavioural thermoregulatory techniques such as; standing with their bums to the weather to shield themselves, using natural windblocks such as trees/hedges or walls to shelter behind, standing as a herd and swapping places so each gets a turn to be warmed by the others, or moving around (muscles are actually very inefficient and for each unit of energy used to create movement, 4 units are wasted as heat!)
Despite these mechanisms, it is still important to consider the needs of each individual horse and the current environmental conditions. Several factors must be taken into account when deciding whether or not a rug is necessary including
- weather conditions – horses lose heat fastest in wet, windy conditions when the temperature is already low, compared with the same temperatures on a still dry day.
- Age – foals have a smaller volume : surface area ratio so are more likely to lose more heat, more quickly than their larger, heavier adult counterparts. Older horses who may have health conditions affecting their body condition, metabolism or mobility are also much more likely to feel the cold than those in their prime
- Diet – diet plays a crucial role in moderating body temperature, forage helps to generate heat so horses with access to ad lib forage are likely to be able to regulate their body temperatures better during cold weather than those without adequate forage
- Hair – Horses have an amazing ability to use ‘piloerection’ (standing their hairs on end to trap warm air for insulation) obviously by clipping them, we reduce their ability to do this so clipped horses are much more likely to require rugs than their unclipped counterparts. ALSO, in theory at least, coat colour should have an effect on heat retention – dark coloured horses are more likely to be able to absorb more of the heat emitted by the sun that lighter coloured horses (some studies have shown there to be a 5C difference in temperature at the coat surface of light horses vs. dark.
- Shelter – is there adequate shelter available? Trees to stand behind and under? hedge lines or walls to block weather from any direction? overhead shelter?
- Activity – how much does your horse move around in their environment? Are they able to move around? I always advise owners of lame horses or those with limited mobility to ensure they remain warm and use rugs as appropriate. Conversely, if your horse moves around alot, are they likely to overheat in a rug? Is the rug more likely to impede their movement, rub in places and cause soreness and discomfort?
- Health status – horses with health conditions such as cushings/equine asthma or those that are colic prone are likely to require a rug when other horses without these health conditions do not.
From a physio point of view, it’s common to see the effects of ill fitting rugs through the winter – increased sensitivity around the pectorals and withers. Ill fitting rugs can cause issues with the skin, coat, muscles and fascia. Heavy, water logged rugs can affect the mobility of horses, especially elderly horses or those that are physically weak and over rugging can result in skin conditions and contribute to obesity so checking for humidity under the rugs frequently is imperative. In the same light, a horse with muscle damage or soreness, lameness or an injury will not benefit from standing hunched and tense, shivering to remain warm.
Ultimately, rugs have a valuable role in keeping our horses warm during Winter months (or on those lovely English summer days where the rain is pelting sideways) but there is a tendency for us to over rug our horses, mainly due to the fact that we, as humans, feel cold at much warmer temperatures than horses do so it’s easy to assume they’re cold when in fact they’re comfortable.
If your horse does require a rug, ensure they get time without it if possible, give them chance to scratch and roll unrugged or chance to groom a mate whilst unrugged. Change rugs frequently, not just when wet. Changing to a different style or fit can help reduce repeated rubbing or soreness. Check for humidity and warmth under a rug regularly, removing it if there’s any sign of potential humidity (sweat).