Cows with ketosis become progressively depressed and lethargic. In severe cases cows lose weight, become dehydrated and show nervous, agitated behaviour such as delerium, bellowing and walking in circles. This is caused by the sudden depletion of the body's calcium reserves due to the onset of milk production after giving birth. If untreated, the cow become progressively weaker and is unable to stand. Suffering from shock and bloating, death follows, most likely due to heart or respiratory failure.
Cows can also suffer from a range of other diseases.
Over 100,000 cases of BSE have been confirmed and as most animals are slaughtered before they are old enough to show any symptoms the true number of infected animals is probably closer to 500,000. This is held to the cows head and the bolt penetrates the brain when fired. However, the use of a captive bolt does not always succesfully stun the animal. The most common failure in stunning is due to improper positioning of the bolt. This is a particular problem where cattle are agitated and struggling.