Winter brings the biggest change in horse management - you are at the stables twice as long, your horse is in twice as long and you ride half as much.
This intimate change, outside of leading to cabin fever, predisposes your horse to a few tricky conditions or perhaps occupational hazards.
Skin disease is the commonest presentation and includes ringworm, lice, mites, and various bacterial infections.
Ringworm is a skin disease caused by a fungus contagious to other animals and importantly to humans. Fungal spores start new infections when rubbed onto skin.
After spores enter the skin, the fungal infection begins in a growing hair. Lesions appear on the forehead, face, or neck and sometimes the root of the tail, but will spread to other parts of the body as typically circular areas in which the hair falls out or breaks off.
Isolate and treat an affected horse. Saddle pads, grooming tools, and anything else which might be used on more than one horse should also be treated and disinfected as ringworm spreads quickly.
Lice (pediculosis) are also mainly a winter problem, thriving in cold weather when hair is long. Lice are tiny parasites which spend their entire life cycle on the host. They are transferred from one horse to another by direct contact or equipment.
Horse lice are not the same as cattle or human lice. Lice from other animals, such as cattle, will not infest a horse, nor is there any danger of humans getting lice from horses. A horse can get lice only from another horse or occasionally from chickens.
You can usually see the lice if you raise the horse’s mane and part the hair underneath it with your fingers. The lice will be down on the skin between the hairs. A magnifying glass makes them easy to see. The hair comes out easily where lice have been feeding and those areas often have greasy skin and heavy dandruff.
Several sprays and dusts can help eliminate lice. A second treatment two weeks later is needed to kill lice which hatch after the first treatment (the eggs are not killed). Before using again treat brushes, blankets, or tack used on the infested horse.
Mites are another tiny insect which cause skin inflammation, hair loss, pustules, and bloody crusts. One type of harvest mite or grain mite infests horses accidentally but can transmit diseases. The horse’s face and lips can become itchy and scaly.
Another type of mite infests hair follicles, causing mange.
Invasion of hair follicles and oil glands leads to chronic inflammation, loss of hair, and sometimes pustules. Some mange mites live deep in the skin, creating nodules.
Other mites cause a severe, itching dermatitis called sarcoptic mange. Affected areas of skin develop red elevated areas and may be injured by the horse’s constant rubbing and biting. These mites are active during cold, wet weather. Mites can be spread from horse-to-horse by direct contact or by bedding, saddle pads, grooming tools, etc.
Leg mange is caused by a mite which lives in the long hair on the lower legs in winter, causing severe irritation and itchiness. The horse will stamp and actively rub affected areas, and eventually the skin may become swollen, scabby, cracked, and greasy.
Rain scald (Dermatophilus congolensis) - is a bacterial infection affecting areas of skin which are moist, hence it is a common problem. The back, lower limbs and areas of coat drainage, plus areas under rugs which are wet due to sweat are commonly affected.
Mud fever is the same bacterial infection when it affects the lower limbs. Fresh lesions present as thick, multifocal superficial crusts and scabs which, when pulled, bring the hairs with them. This is a self-limiting disease in mild cases which will resolve within a month in dry conditions.
Rugging seems to cause more harm than good. If treatment is desirable, cleaning (three times weekly) and removal of scabs and crusts by gentle scrubbing with a very dilute solution ofantibacterial wash is best.
However do not apply topical ointments until the area is thoroughly dry, as applying barrier creams seal in skin moisture creating a microclimate for bacteria to thrive.
The next commonest presentation in winter is respiratory disease. Good air quality is essential to the health of a stabled horse no matter what the season of year. But in winter, when your inclination is to cover windows and vents, disconnect fans and shut barn doors, inadequate ventilation can cause serious and long standing respiratory problems.
While viral and bacterial infections have been shown to increase in young animals over the winter months, many are relatively short-lived, eminently treatable and largely preventable through vaccination.
More serious is their then predisposition to the development of Recurrent Airway Obstruction (RAO) previously known as COPD. It is caused by an allergic response to different environmental allergens, although viral infections predispose to earlier affliction. It will mainly present during the winter months, when horses spend more time in stables.
Allergenic micro-organisms in hay, including bacteria, fungi, and minute particles of feed grains, faeces, dander, and pollen become aerosols when the horse feeds. Once inhaled, they elicit an allergic response.
Four to six hours after a horse with RAO is exposed to dust from hay, the airways become acutely inflamed and vast numbers of neutrophils accumulate. These cause the airways tobecome narrowed, oedematous, thickened and covered with viscous, sticky mucus, obstructing normal air flow, which increases the effort required to breathe.
Lifestyle changes are the first line of defence against RAO. If these are not effective, or the horse is suffering acutely, treatment including corticosteroids and bronchodilators are standard. However, treatment will be largely ineffective if management factors involving the horse’s environment are not addressed.
Dust and moulds will need to be reduced or removed from the horse’s quarters and, if possible, from neighbouring stalls. Turn the horse out as often as possible.
Ensure there is draught free ventilation through the stable. Half doors and large windows should be kept open, as it is better to keep the horse warm by providing more rugs than by closing ventilation.
If your stable has lots of cobwebs and/or mould patches on the roof then it has poor airflow. And if your stable adjoins others, their management needs to be as good as yours.
The last area to touch on is colic. Drier, more fibrous feed, less exercise combined with a lower water intake will potentially lead to an increase in the number of medical colics seen. These can be frustrating to treat and manage since encouraging your horse to change its diet, drink more or your opportunities to ride are handicapped.
Warming water, keeping a note of faecal output, adding extra succulent feeds to the diet are all helpful, but may be a trial and error management solution.