Winter Colic: The Dangers Of Cold Weather | Equine Science Matters™

With a winter cold snap, there is usually an increase in the number of colic cases, especially in stabled horses fed hay, older horses, or those prone to feeling the sudden drop in temperature. 

As the temperature drops, so does the temperature of the drinking water. Even when we’ve taken the ice out of the bucket, the water beneath is still often barely above freezing. While drinking cold water doesn’t lower a healthy horse’s core body temperature by any significant degree, it can be more than a little bit uncomfortable and therefore discourage horses from drinking enough. As forage is chewed, swallowed and moves past the stomach, it needs to be an almost soup-like consistency to move easily through the convoluted folds of the digestive tract. It is only as it passes through the final stages of digestion and into the colon that the extra water is reabsorbed, and firm droppings are formed. When the horse isn’t drinking enough, the material passing through the digestive tract is much harder for the muscles surrounding the intestine to move along.  

The harder it is for the digesta to move through the intestine, the higher the likelihood of gases produced during fermentation building up, unable to escape as normal. While impaction colic is usually thought of as the main gastrointestinal risk with dehydration, gas colic can also be a serious and related issue. 

Many horses move less during cold weather, either because they’re stabled or choose to stand still in a field to conserve energy or stay in a sheltered area. As movement is key for helping move digesta and gas through the intestinal tract, a lack of movement can compound any digestive issues resulting from dehydration. 

With any signs of colic, such as kicking up at their tummies, looking around at their tummies, unusual sensitivity to being touched or groomed around the barrel, lying down and standing up more frequently than usual, fewer droppings than usual, or a lack of appetite, it is important to call your vet. Early intervention is often key to preventing much more serious issues from developing. 

Preventative steps 

1. Monitor and encourage water intake 

• Where horses are stabled or turned out individually, monitor water intake to check they are drinking as much as usual. As a rough guideline, horses should usually drink 5-10% of their bodyweight daily, so a 500kg horse would need 25-50 litres per day. However, this can vary with feed and forage type. Those on a hay diet need the upper end of the guideline, while grass or haylage contains a high amount of water, so the horse would be likely to consume nearer the lower end of the scale. 

• Provide room-temperature (or just below) water twice a day. Where there isn’t a kettle in the yard, taking a large thermos of very hot water and adding that to a bucket of tap water would suffice. 

• Adding a splash of Ribena or a spoonful of molasses to warmed water can help encourage drinking. 

2. Warm mashes 

• While we wouldn’t want to change our horses' feed drastically, making their usual feed into a sloppy mash consistency by adding warm (not boiling) water and leaving it for 10 minutes or so can help increase fluid intake. 

3. Encourage movement 

• Ensuring turned out horses are warm enough through feeding ad-lib forage and appropriate rugging so that they feel less inclined to stay still to conserve energy. 

• Ensure dental checks are up-to-date to  

• When the grass is too snowy or frosty to graze, using a treat ball with some grass nuts can help mimic grazing behaviour and movement. 

• Taking stabled horses out for an in-hand walk a couple of times per day, or turning them out in an arena, can help.  

• Exercise doesn’t need to be vigorous; in the same way as a gentle walk after lunch helps humans digest and reduce bloating, a 15-20 minute walk a few times per day on a safe, non-slippery surface can be enough to help. 

4. Consistent feeding practices 

• When winter conditions mean inconsistent turnout times and routines, this can represent a fairly significant dietary change, which can further increase the sensitivity of the digestive system and risk of colic. Including grass in the form of grass chop or soaked grass nuts when stabled for longer than usual can help maintain a greater degree of consistency in terms of nutrient intake. 

The weather can cause significant challenges to our horses’ digestive systems, from risk of impaction and gas colic due to dehydration, through reluctance to drink cold water, lack of movement, or even dietary change related to variable turnout schedules.  

Trying various strategies to keep horses hydrated is a key ally against winter colic, while encouraging movement to help gut motility can also be a great help. Ensuring as consistent a diet as possible when turnout times vary can also help keep the hind gut and microbiota healthy.