1932 ANNUAL REPORT, 1931 11 



foxes; but due to improved methods of feeding it has largely disappeared on 

 the better managed ranches. No doubt as mink breeders acquire a better under- 

 standing of the underlying causes of diseases, it will tend to become less frequent 

 among their animals. 



Food poisoning occurs very suddenly and only two or three animals may 

 be affected at one time. Where several mink are affected, the owner may think 

 that he has to deal with a contagious disease. The mink, in all probability, have 

 been in good health and suddenly two or three will be found dead in the nest 

 boxes. The condition may disappear for three or four weeks or even for several 

 months, or it may even have the appearance of a seasonal occurrence. The 

 history and circumstances surrounding the deaths are difficult to explain and 

 the rancher is at a complete loss to understand them. 



Food poisoning is a condition which affects animals and is caused by the 

 formation of toxic or poisonous substances in food material, usually by bacteria 

 and moulds. When eaten, these bacteria and moulds often cause digestive 

 disturbances of varying degrees of severity. 



The blood, flesh, or any organ of an animal may acquire poisonous properties 

 through the products of bacterial growth. These poisons can be explained in 

 part by the growth of bacteria in the food stuff and the formation of poisonous 

 products. It should also be understood that under certain conditions, food, 

 which to the eye or nose is not spoiled, may already contain bacteria which 

 may de^•elop in the stomach and intestines of the individual eating the food, 

 resulting in food poisoning. 



Meat poisoning can occur after the ingestion of meat derived from horses, 

 cattle, or calves which have died, or have been slaughtered at the point of death, 

 usually as the result of some disease. If the disease is of bacterial origin the 

 danger of feeding such meat is obvious, but there is considerable evidence that 

 such animals are frequently used as food. 



Another group of food poisoning cases is associated with putrefactive 

 changes, which, unlike the former group, are quite noticeable to the feeder. The 

 meat or fish, as the case may be, is obviously bad; it has a slimy appearance 

 and an offensive odour. This is apt to take place with meat or fish that has been 

 repeatedly thawed out and frozen in periods of changeable weather during 

 early fall and late spring. In some cases only small areas may be affected but 

 these are sufficient to kill two or three mink. During these periods of repeated 

 thawings, the chemical composition of the meat will become changed and form 

 a media favourable for the growth of poisonous bacteria which have been kept 

 in check by freezing. This is especially true of horse meat on account of its 

 high sugar content. 



Ranchers may argue that decomposed meat has been fed with no bad 

 results. This may be true in some cases if bacteria of a poisonous nature have 

 not developed in the meat, but the odds against this happening are much too 

 great for the rancher to take the risk. 



Animals pre\iously treated with drugs such as coal oil, turpentine, str>chnine 

 and other stimulants, which become diffused through the flesh in a short time 

 after administration, when fed to mink may cause death. Such meats are usually 

 difficult to keep from spoiling. 



Alouldy and ropy bread is one of the most insidious forms of food poisoning 

 encountered in mink. Bread may, to all external appearances, appear to be 

 (|uite fit for food but in realty may be very dangerous. 



Ropy bread when rolled between the fingers will be moist and stick\- and 

 have a sickly, sourcdour. It spreads into small fine threads which have a spider 

 web appearance. When mixed with milk and allowed to stand for a while, it 



