1934 ANNUAL REPORT, 1933 13 



"sheath trouble" is descriptive of one of the common symptoms of anaemia 

 in the advanced stages of the disease, but a degree of anaemia may exist 

 without sheath trouble being apparent and the term is not applicable to 

 the female. For these reasons the term is not satisfactory as applied to 

 the disease in question, as it does not give any clue to the true ilature of 

 the condition. The term acidosis is also open to criticism. Authorities 

 on the subject are in no way agreed upon its real significance. Acidosis 

 is not a disease in itself but is a complication which may exist in conjunc- 

 tion with a wide variety of diseases. Therefore, the use of the term in 

 describing a definite and established disease in mink is not justified and 

 should be dropped from the literature. 



SYMPTOMS 



A decline in the general welfare of the mink is the first noticeable 

 symptom The fur becomes brittle, harsh and dry and lacks lustre, colour 

 and sheen of the adequately fed animal. In the regions of the neck and 

 tail the fur has a moth eaten appearance and is also open and short over 

 the back. A decline in weight takes place as the disease progresses. Due 

 to the constant dribbling of urine the sheath becomes wet, the abdomen 

 bare of fur, and the skin inflamed. In advanced cases the penis protrudes 

 and the sheath is swollen and tumour like. The eyes lose their bright 

 beady appearance and become somewhat sunken in the head. A^- the 

 disease progresses the mucous membranes, including the lining of the mouth 

 and eye become pale. The tongue has a blanched appearance and the foot 

 pads are conspicuously white and bloodless. Shortly before death the 

 mink may commence a nervous weaving movement with his head and 

 body, the appetite fails and he becomes dull and sleepy. In these later 

 stages the eye has a squinted look. Twitching of the legs accompanied 

 with convulsions and gasping for breath is manifest. Finally the animal 

 dies in a comatose condition. 



CAUSES AND PREVENTION 



In studies carried out at the Ontario Government Experimental Fur 

 Farm it was found that the disease could be produced experimentally with 

 regularity and certainty and that the symptoms and pathology were 

 identical with the condition as it prevails on mink ranches. The outstand- 

 ing feature from the pathologist's point of view is the presence of normo- 

 blast cells, and the irregularity in size of the red blood corpuscles in the 

 blood stream. When found in any number normoblast cells are always 

 indicative of anaemia, particularly the pernicious forms. In mink the 

 red blood counts and hemoglobin may show a reduction as low as fortv 

 per cent, of the normal. 



A large number of diets, considered adequate from the nutritional 

 standpoint, have been fed on ranches where the condition has appeared 

 from time to time. F'or example, the following rations produced the earlier 

 symptoms of the disease, namely sixty percent, fresh meat, consisting of 

 beef hearts, tripe, and muscle meat, twenty-five percent, cereals, ten percent 

 bone meal, five percent vegetables and small quantities of milk, wheat 

 germ and yeast. A number of similar diets, all of which apparently con- 

 tained a sufficient variety of food staples, did not give entirely satisfactory 

 results. Where fish was substituted for meat, the condition also appeared. 



It was not until the disease was recognized to be of anaemic origin 

 that measures could be taken to prevent its occurrence. It was found that 

 when small quantities of liver were added to the diet that anaemia did not 

 develop. The curative efi"ect of small quantities of liver in the diet during 



