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New Yorh 14609 USA (716) 482 - 0300 -Ptione (716) 288-5989 - Fa« ^^^^ /l/AXC- DOMINION OF CANADA THE HONORARY ADVISORY COUNCIL PCHaCTENTIFIC AND INDUSTRIAL RESEARCH BULLETIN No. « SOME PROBLElVfS OF THE FOX-RAISING INDUSTRY BY ANDREW HUNTER, NlA..||3c.»MAwaj. PirofeMorofBiocheaiwtr^-lJyimri^.«^^ ■ Publuhed by the -'hrriff tf tfij TiiTi fiiniiiiaiii ijf ^ |Wvy Caonca f or Scitatiik Mid btUrikl R«M«Gii OTTAWA. 4^20 SOME PROBLEMS OF THE FOX-RAISING INDUSTRY. iNfROUt'CriON. The business of fox-breeding, which in the years before the Great War was little more than a speculative adventure, is today a solid commercial enterprise, success in which depends entirely upon the number and qudlity of the pelts actually sold. In this character it has already attained a truly surprising magnitude. In Prince Edward Island alone there are about 275 fox farms with, it is conservatively estimated, at least 4,000 pairs of breeding foxes. During the season 1918-19 there were offered for sale, at prices ranging mostly from $250 to $1,000, approximately 5,000 skins, and the total revenue of the Island from this source must therefore have been little short of $1,000,000. When it is considered that this province is not the only one in which foxes are raised for their fur (ranches have been established also in New Brunswick, Quebec, Ontario, Manitoba, etc.), and when it_is further realized that the pelts produced arc practically all exporteid, it becomes evident that the industry may justly claim not merely a local, but a national im(K), Umce, which is very far indeed fron oeing negligible. Needless to say, it has not reached this st. . v/ithout encountering a variety of difficult problems. It is th purpose of the following pages to inquire into the nature of these, and to consider whether it would be profitable, and in what manner it might be possible, to attempt their solution. I. The Aver.\gk Yield and the Possibility of Its Improvement. It can hardly be doubted that under existing circumstances the returns of the industry are on the average lower than they need be. It is, to be sure, impossible to ascertain with exactness either the total number of fox pups born in a given year, or the total number raised to maturity; but the information available would suggest that the 4,000 pairs of adult foxes in Prince Edward Island raised successfully last year not much more than 5,000 7WH—1 1 pups. This would bean average yield jf only 1 -25 per pen. Since the number at a birth is seldom less thaii 3, and is often from 5 to 7, It is obvious thai -uch a figure indicates either a large percentage of infertile matings, or very considerable lotwea among the growing pups. The exact importance of the first factor cannot at present be even roughly estimated, Hut as retrards the second it would appear to be establiihed, upon the independent testimony of many exper- ienced breeders, that from 40 to 60 per cent of the foxes accually bom never reach maturity. The losses thus indicated are largely avoidable, for there are individual ranches where the yield is very much higher than the estimated average. In many it is over 2-5, and it appears that it may sometimes even exceed 4. .What can be accomplished by some ranches ought not to be impossible to any. It would be hard to say what may be ihe pr^ictical limit of improvement, but it the actual yield l>e taken as 1-5, and the generally attainable set no higher than 3, it would seem not unreasonable to hope that the revenues of the industry might, by scientific mana^ iient, at least l>e doubled. II. Factors Responsible for the Low Rate of I.ncrease. The factors responsible for the low average rat • of increase are evidently very numerous, and are not always readily deter- minable; but most of them appea.- to be classifiable under one or other of the following heads: 1. Infectious Diseases. 2. Parasites. .^. Food PoisoninR. 4. Imperfect Nutrition. 1. INFECTIOUS DISEASES. Several ranches are known to have been visited by distemper within the last few years, and it is suspected that others have suffered without permitting their misfortune to become public. While the loss thus caused to the industry as a whole represents probably but a small fraction of the total revenue, a single outbreak may spell at least temporary disaster for jhe individual. It hardly needs to be said that the problem presented by distemper is mainly one of prevention. From this point of view the existing practice of many ranches is certainly capable of a improvement. It ..ught for instance to lie a matter of routine, that every fox introduced from another l, but the foxi-s should Ik^ more riKiilly isolated than at present from every contact, direct or iiidireit, with other aiiimul;* It is not definitely known what sfH-cies are, and what are not, ca|>id>le of harlmring or tran nitting the specific virus of distemper; Imt it would obviously b«' ihc part of wisdom to exclude every kind of animal, domesticated or wild, not only from the neighlKJurlKMHl of the fox ranch, but also from the society of the keeper. Should dislemix-r once make its appearance in a ranch the most strenuous steps must Ite taken to prevent its spread. The (Mily ho|K- of <|oing so, apart from the ust', as yet in its experimentul stage, j)f protective vaccines, lies in the prompt and complete isolation of the aflecfcd animals, and the thorough disinfection of their jK'ns. Such a proscs of course the (Mis- session by the infected ranch of a s|K'cial group of pens, separatee determined. In any rase it will l>e ncccs.sary in the future for the fox breeder to pay attention to this hitherto unsuspected enemy, and to initiate measures for effectively cf.ntrolling its spread. He can hardly do so withoi-t the advice of an expert, and the assistance afforded hy a readily accessible laboratorj'. .1. KtKJD I'OISONlN(;. .\(Hte food |)oisoning has on .several oci i>ions b> .1, res|K)nsibl<" for serious losses among both young ar.i crafive system, whereby all meat intended for foxes should be first inspected, and then properly stored in <-old stor.ige plants at a sufificient number of readily available centres. 4. IMl'ERlliCT XUTRITIO.V. However important the factors of loss hitherto discussed, their elimination would leave the average yield of the ranches still far below its possible maximum. The fundamental problem of the fox farmer, as of every breeder of animals, is one «.f nutrition; and it is the failure fully to solve this problem that occasions at present the most serious losses to the industry. If a fox, or any other animal, is to be maintainele vitamine, in which the brxly fat of animals is not particularly rich, but in the general interest of a well balancctl ration. Offal, such as liver and tripe, is a good source of the fat-soluble vitamine, and might with advantage be much more generally utilizcxl than it is. Greens would supply not only \itamines but also calcium, though it is me kinds of desiccated vegetable could be successfully utilized. E^s are capable of supplying every requirement of a growing animal, except possibly calcium, and will of course supply this also if the shell is eaten. Milk, in sufficient quantity, will make good any dietary deficiency whatsoever, and the more extensive use of milk, when necessary suitably modified, would perhaps solve not a few of the nutritional problems at present confronting the fox raiser. It is true that milk already occupies a place in the diet list of practically e%er>' ranch I have visitod. But it may be questioned whether the amount fed is universally sufficient to make good the defects of the meat and cereals which supply the bulk of the nutriment. There exists among breeders some differ- ence of opinion as to the liest form in which to administer milk to foxes. The proper practice would probably be to use only faw whole milk. To remove the fat is to remove an important nutrient, in which the diet as a whole is already deficient, uini with it the as.sociatcd fat-solubie accessory; while to heat the milk is to destroy or diminish its vitamine content in general, and therefore seriously to affect its gro'vth-promoting and protecti/e properties. When cow's milk is used for the feeding of very young foxes, it ought, we may assume, to be so modified as to approximate in composition the milk supplied by the vixen. Unfortunately the exact composition of the vixe milk is not known. There is on rtrord i)ut one analysis, and ti.at a very imperfect one, of a sample which may or may not hove represented a fair average. So far as it goes it indicates a much higher fat and a much lower sugar c(jntent than cow's milk. This is quite in accord with what is known of the milk of small animals in general. It would therefore seem reasonable to use for the growing pup cow's mil': of the highest obtainable fat content, and L\'en to enrich thi by the addition of a suitable amount of cream. But before the fox breeder can be furnished with authoritative guidance in the adap- tation of cow's milk to the successive stages of the young animal's growth, it will be necessary to secure more comprehensive and J accurate data upon the composition of vixen's milk, not only in regard to organic but also inorganic constituents. The immediate need of such data should not be forgotten in any experimental work which may be planned in the future. The dietary imperfections, to the probable existence of which att«ntion has been drawn, are likely to be most conspicuous during the winter season. The reason for thinking so is that milk is never included in the diet until after the pups are born in the early spring. This situation is the more unfortunate since a diet of meat and cereals alone furnishes a particularly jxHir provision for the requirc.iients of pregnancy and lactation. If the practical difficulties that have hitherto excluded milk from the diet of the pregnant female cannot be overcome, other sources of calcium and of the fat-soluble accessory become an absolute necessity. Eggs (with the shell) would provide both, bone-meal might be useful in supplying the former, and the latter could be derived from the liberal use of liver, tripe and other glandular materials. Many of the most successful ranchers have been led by experience to include one or more of these articles of diet in their winter regime. In others the situation is perhaps saved to some extent by the use of cod-liver oil biscuits. Reference has been made to the possibility of a deficiency of calcium in the diet of the foxes. The other inorganic constituents of the food also demand attention. Many caretakers appear to be very much afraid of giving their foxes too much common salt, and it would not be surprising if this fear led c casionally to a deficiency of sodium. It might be a gofDUSTRY. The problem of reaching and maintaining a maximum return involves more than the successful rearing to maturity of every fox that may happen to l)e } rn. It is of equal importance that the number born should be as great as the nature of the case makes possible. This implies that in any complete study of the problems of fox-raising questions of fertility and fecundity must be taken into account. These are undoubteilly in part q;:«stion8 of nutrition, but other factors— hereditary, psychical, climato- logical, etc.,— are also in varying degrees involved, and it would be desirable to have their relative importance more exactly eluci- dated. A not irrelevant ,|iiestion is that of proper age fcr the first reproductive effort of the adolescent am. i.kl. It has l)ecome the practice to mate the foxes selected for breeding purjxises at the earliest possible moment, that is, in the winter following their birth, while they are yet less than a year old. It is very doubtful vhether this is a practice to be recommended, and it should Iw cinsidered whether it would not in the long run Ite more economical to postpone mating till the animals reach their second w inter. A series of co;iiparative tests might be plannetl to throw light upon this problem. Again, mere numbers is not enough. The final aim of the fox-'" idustry is the production, not sa much of perfectly nourished and healthy animals, as of valuable pelts. These are by no means necessarily the same thing. A red fox may be physiologically as perfect an animal as it is possible to conceive- in the market value of its fur it may be far surpassed by a pure-bred silver fox exhib- iting the worst deformities of rickets. The fox in captf.ity is bred in short for certain special characters, and a failure to present these in perfection is as definitely a source of loss to the owner, as eariy death from malnutrition. Beside the fundamental problem of nutrition we must place therefore the fundamen::al problem of breeding and inheritance. The more important aspects of this problem, as related t