12 DEPARTMENT OF GAME AND FISHERIES No. 10 



Possibly there is no more serious loss to fox ranchers than the annual 

 mortality which takes place in young pups, either prematurely born or 

 from one to ten days of age. Up to the present time no satisfactory ex- 

 planation has been given for these losses. Experimental studies were com- 

 menced in an effort to secure more information on the subject. So far, 

 it has been determined that many young fox pups which die or are pre- 

 maturely born are heavily infested with the larvae of the round worm. 

 {Toxocaris cams) and that these larvae are responsible for a severe pneu- 

 monia, but which is not obvious upon post mortem examination. When 

 the infected lung is stained, sectioned and examined microscopically the 

 condition is quite apparent. It is considered that the larvae pass from the 

 pregnant female to the pups while they are still in utero and it is hoped 

 that further studies during the whelping season when material will be 

 available foi examination and also experimental animals that some 

 satisfactory conclusions will be reached which will make it possible to put 

 into effect efficient control methods. 



Parasitism still remains one of the major problems in foxes. It was 

 found during the summer that even such a common and prevalent parasite 

 as the flea was responsible for a severe anaemia which if not checked, 

 would have resulted in the death of the infected animals. These findings 

 were consequently published. 



As little or nothing is known regarding the phenomenon of hibernation, 

 the subject is receiving attention in the hope that some interesting and 

 instructive data will be compiled. 



Routine duties, such as correspondence, autopsy examinations and 

 interviews with fur farmers all show a decided increase over previous years 

 and take up a considerable portion of time each day for the two members 

 of the technical staff. 



A successful year was experienced in raising foxes, mink, raccoon and 

 beaver, but no successful results have, as yet, been obtained with fisher 

 and marten. Both of these animals constitute a baffling breeding problem, 

 especially when it is considered that they take readily to captivity and at 

 all times appear to be active and in the best of health and condition. 



A number of foxes and raccoon were released from the Fur Farm to 

 the Chapleau and Nipigon Crown Game Preserves and returned to their 

 natural surroundings where it is hoped that they will become established 

 and a future source of fur-bearing animals in these districts. 



Articles of interest to fur farmers engaged in the raising of mink and 

 foxes w^ere prepared by Drs. R. G. Law and A. H. Kennedy of the Ex- 

 perimental Fur Farm staff and published during the year, and in view of 

 the value of the information contained therein, they are included herewith 

 as a portion of this report. 



NUTRITIONAL ANAEMIA IN MINK 



By Ronald G. Law and Arnold H. Kennedy 



Among the diseases of mink, which have come to our attention during 

 the past few years, anaemia appeared to be more commonly met with than 

 any other. 



The symptoms appear to have been recognized under the somewhat 

 loose and ambiguous terms of acidosis and sheath trouble, but the true 

 nature of the disease does not appear to have been established. The term 



