Page 469 - The Veterinary Care of the Horse

• gradually sink.

• The horse becomes anxious and is increasingly reluctant to move forwards.
VetBooks.ir Other symptoms include:

• excessive sweating
• muscle fasciculation (small spontaneous tremors)

• an increase in heart and respiratory rates

• pawing the ground and mild colicky signs

• repeated attempts to urinate as adopting the normal stance for this is uncomfortable

• passing urine which varies in colour from normal, through reddish brown to dark
chocolate; the discolouration is due to a pigment called myoglobin which is released

from the damaged muscle fibres (Figure 11.3)
• resentment of pressure on the affected muscle groups which may include the gluteals, the

lumbar muscles and those that make up the hamstrings, i.e. the biceps femoris,
semitendinosus and semimembranosus

• dehydration

• raised temperature
• synchronous diaphragmatic flutter (thumps). Spasms of the diaphragm cause the horse to

show signs similar to a human with hiccups

• the horse becomes recumbent (unable to stand) in very severe cases.
• kidney failure and death may occur as a result of circulatory failure and damage to the

kidney tubules by myoglobin.