Written by: Dr. Shannon Pratt-Phillips
Horses coping with chronic obstructive pulmonary disease (COPD) or recurrent airway obstruction (RAO) – also known as ‘heaves’ – don’t have specifically different nutritional requirements, but feeding management is critically important.
COPD and RAO are very similar to asthma in humans, and are a result of an allergic response to airborne irritants, namely dusts and molds. Therefore, in an effort to feed and manage these horses, their exposure to these irritants must be reduced.
The best way to manage horses with COPD is to keep them outside as much as possible, where there will be fewer irritants to cause problems for the respiratory system. Even if pasture is not available, it is likely that the dust from fed hay will be blown away rather than inspired by the horse.
That said, selection of hay, even if fed outside, is an important consideration. Round bales, where a horse might put his whole head into the core to eat, can be counterproductive to a COPD horse staying outside. Smaller bales, or unrolling large round bales, would be more suitable.
In terms of feeding, hay selection is extremely important for COPD horses. Most hay will contain some dust and mold, so it should be soaked or steamed prior to use. While commercial steamers may be an effective way to kill mold spores and decrease dust, homemade steamers also appear to work well. (Instructions for several homemade varieties can be found online.)
Soaking hay can also decrease dust, but if not consumed readily, wet hay may actually increase mold development. Fresher hay – rather than last year’s batch – will also contain less dust to begin with, as the more fragile leaves are reduced to dust with prolonged storage. When feeding soaked or steamed hay, be sure to weigh out the amount your horse requires before making it wet.
If hay soaking or steaming is not viable, owners should consider looking at forage alternatives. These are products that are very high in fibre (as is hay) and will provide sufficient fibre to maintain the microbial ecosystem within the horse’s digestive tract. Hay byproducts such as haylage (fermented hay), hay cubes, or pellets are an excellent, low-dust alternative to long-stem hay. Just take note that if you feed haylage, you may want to have your horse vaccinated against botulism. Haylage can be contaminated with the botulism bacterium during the raking and baling process and the high moisture levels, anaerobic conditions, and pH levels create ideal conditions for the growth of botulism toxin. If you purchase haylage from a trusted producer, this is rarely a problem.
Typically, hay cubes can be fed in similar weights as you would feed long-stem hay; i.e., if you feed 10 kg of hay, you would feed 10 kg of hay cubes. Haylage would be more difficult, because it has a higher moisture content than hay. Working with your haylage supplier or an equine nutritionist can help you figure out how much haylage you would need to feed your horse to replace long-stem hay.
Other high-fibre hay alternatives include beet pulp or rice bran. Amounts to feed and ways to balance your horse’s diet can be discussed with your nutritionist.
In terms of supplemental feed such as grains that are fed to increase calories or other nutrients, again look for products that are low in dust. Many pelleted products are lower in dust than feeds such as oats, but fines at the bottom of the bag should not be fed to horses with COPD. Soaking feeds, particularly pelleted commercial feeds – and also beet pulp/rice bran/hay cubes – can also reduce the dust exposure to a COPD horse. Alternatively, adding vegetable oil can also decrease the dust levels,while increasing the calorie density of the diet (if needed).
Horses living inside can manage with COPD if their feeding program and daily care results in minimal dust or mold exposure. Bedding selection can play a large part in this; products such as hemp, peat moss, and shredded newspaper tend to be low-dust, while shavings, sawdust and straw are dustier. The level of absorption of liquid and ammonia, which is derived from nitrogen in urine, is important as well, as it can irritate the respiratory tract. Products spread in the stalls that reduce ammonia in the surrounding environment can be effective, while soft stall mats may minimize the need for deep bedding (and hence dust).
How horses are fed inside is also a factor. Many recommend feeding horses with COPD on the ground to avoid any airborne dusts displaced from an elevated haynet or feeder. However, feeding closer to the ground also brings the horse closer to the bedding. If the bedding is low-dust and horse is fed in a low-sided tub that separates the feed from the bedding, but prevents the horse’s entire head from being enclosed, any impact of airborne dusts should be minimal.
Other inside management practices for COPD horses include stabling them away from where hay is stored, as when bales are opened and flakes pulled apart, additional dust is released into the air. Wherever possible, these horses should also not be housed next to horses deeply bedded in straw or other material containing dust particles that may travel.
Another practical action is consistency. Research has shown that even if horses are only exposed to dust for a short period of time before going back outside or to a less dusty environment, the respiratory system of the horse may still be negatively affected for several days. Therefore, owners of COPD horses need to be consistent in their management, keep their horses outside as much as possible, and aim to minimize dust and mold exposure throughout the rest of the horses’ lives.
With fresh air and good nutrition, horses with COPD can lead productive lives with minimal medication. Always consult with your veterinarian for medical issues regarding your COPD horse, and ask your nutritionist about a suitable feed program.