Page 743 - The Veterinary Care of the Horse

diet is suddenly changed, the fermentation process is disturbed and the horse may suffer from

colic, constipation (known as impaction) or diarrhoea.
VetBooks.ir of two weeks. This allows the bacteria time to adapt to the different food.
In order to avoid such problems, changes to the diet should be made slowly over a period

Wild horses graze almost continuously, whereas domesticated horses have their food
intake controlled. This can lead to problems, especially if the horse eats large volumes of
roughage in a short period of time. Impactions may develop at any of the three U-bends

(known as flexures) in the large intestine. A horse normally passes droppings every couple of
hours.

Water is absorbed as the food passes through the large intestine.

RECTUM

Undigested residues from the food eaten by the horse pass into the rectum and are expelled as
faeces through the anus.

CHOKE

Choke occurs when food material becomes impacted in the oesophagus (gullet) and does not
pass into the stomach.

Clinical signs

These include:

• coughing
• holding the head and neck in an extended position

• retching and difficulty swallowing: the horse often flexes and then stretches its neck

during an attempt to swallow; at the same time it may grunt or squeal in
pain

• trickling of green/brown fluid or clear saliva and food material from the nostrils (Figure

17.2)
• saliva drooling from the mouth

• a swelling may sometimes be seen along the line of the oesophagus on the left side of the

neck
• some horses become very distressed and show colicky signs.