Welcome to this month's issue of UK-Vet Equine, my first as editor. As the summer months come around, many horse owners are able to turn their horses out 24 hours a day, allowing a much more natural way of life for their animals – and a welcome break for their bank accounts! Horses benefit hugely from longer periods of turnout – it allows more movement, better gut diversity from grass (as opposed to cereals) and more opportunities for social interactions when turned out with other horses.
While humans might enjoy the heat, it may not be ideal for our equine companions. Horses can self-regulate their body temperature up to around 30°C (Cymbaluk and Christison, 1990), so when provided with adequate shade and water supply they can often be left to enjoy the sun. However, light coloured horses with pink skin can be prone to sunburn (Young et al, 2013), so it might not just be owners who should be reaching for the sun cream! Additionally, heatstroke can be a potential problem; horses who are overheating should be treated initially with the application of cold water – this will help reduce the body temperature (Takahashi et al, 2020), and a vet should be called. To help prevent heatstroke, horses can be hosed with cold water and left wet, rather than scraping the excess water off.
Horses who are prone to conditions such as equine metabolic syndrome and laminitis may also be difficult to manage over the summer months, due to the increased amount of grass and increased sugar levels in that grass (Crawford et al, 2007). These horses should be kept on a controlled diet to ensure that they remain at a good weight – as such, any change in their turnout routine should be carefully considered. For example, horses may be turned out in a grazing muzzle so they can stay out in the field longer without hugely increasing their calorie intake. Additionally, they could be turned out earlier in the morning and brought in for the afternoons – this is because grass has higher sugar levels in the afternoon, as it makes and stores sugars during the day to fuel its overnight growth (Kramer et al, 2021).
Even horses who are not prone to metabolic conditions can require close management through the summer, particularly if they are transitioned from winter grazing to a fresh pasture for summer. As the digestive system of the horse is so sensitive, it is common practice to make this transition slowly, over a number of days or even over a week or two. The change in the nutritional quality of winter grass, which may have been their main source of grazing for months, to new, untouched summer grass can cause horses to have symptoms such as diarrhoea (Garber et al, 2020) and colic (Tinker et al, 2010). Colic can be hugely stressful for both horses and owners – as I can tell you from experience after spending a night waiting for my own horse's stomach to settle after his first day out on his summer grass!
All in all, the summer can be a lovely time for horses and owners – the increased daylight hours and better weather can make for longer rides in the countryside (if you're lucky enough to have access to suitable places!), but there are a number of things to keep in mind to ensure that horses are comfortable during the hotter months.