STERILITY IN DAIRY CATTLE

Hawke's Bay Herald-Tribune, Issue 77, 17 April 1937, Page 19

STERILITY IN DAIRY CATTLE

Effect of Minerals on Pregnaricy VITAMINS IMPORTANT It is with cows that calve during the late autumn and winter months that delay is most frequently experienced in getting in calf again regularly. Putting aside/ for the mOment, the question of actual disease, this delay may be due to two main causes: the cqws not coming-intb heat and missing the heat periods. Failure to come into heat may be due to an animal being in such a pOor and under-nourished condition that the generative organs fail to act, or the other extreme in which the ovaries aTe so embedded in fat that the ova do not come to maturity. After serviee during a heat period, the follicle in the ovary from which the ripe ova has been diseharged closes Up- ahd becomes converted into a corpusluteum, or "yellow body," whether pregnancy oCcurs or hot. This persists in the ovary through the whole of fne gestation period, but UQrmally djsappears when pregnancy does not occur. The time taken for .the disappearance of the corpus luteum .corresponds to the interval between heats, but does not and cannot occur, as in the case of the pregnant animaL A persistent corpus can quite easily be detected by a manual exaininatioh of the ovary thfough the wall of the rectum, and wheh it is dislodged by pressure of the fipgers tbe cow'co'm'es into heat in the courSe of a few days, and may be seyved with every prospect of her holding. l.ess frequently, failure to come into heat may be ' due to mineral and ^ vitamin- deficiency in'the food; Outstanding in' this respect ate iodine and the reproductive food accessory vitamin E, Which is normally found in sufiS.cient quantity in the ordinary farm foods, but ^specially in thc germ of wheat. Vitamin Deficiency . Recent researches, however, have shown that the- proportion of this vitamin' gradually diminishes as the time between the milling and feeding of the wheat iincreases. Praqtical ways of guarding against vitamih U deficiency are to feed only freshly milled foods, or to mahe good the deficiency by the addition of wheat-germ oil. Minbrals Gan ■ be upplied by feeding white-fish meal or adding a mineral mixture, but here again vitamin D is necessaty for their proper assimilation. There is no difliculty about this vitamin when the cows are out to grass, but in the winter there may be a deficiency of it. This is best met by the addition of cod-liver oil to the food. As regards minerals and vitamins, however, in addition to the non-appear-anee of heat, a serious deficiency of either, or both," m'ay render it impossible for the fertilised ovum to survive, and although the cow may be served, she repeatedly comes into serviee again. It is quite possible to.miss the heat periods, as during the winter months they are less marbed and of ahorter duration. The period is, on the averUge, six houra as against 16-30 hours in summer, so that a cow may come on heat in the evening and refuse to take the bull in the morning. Infertility due to cows returning to serviee is a far more difflcult problem to solve beeause it is nearly always due to diseased conditions of the generative organs or tract. Even when these can be run to ground they aTe by no means easy to cure, and may in fact prove incurable. A diseased condition of the ovaries may result in continual heat (or heat at much shotter intervals tha'n normal) and an unnatural state of sexual exeitement to which the name nympliomania has been given. In many cases this trouble is due to cyst formation in the ovaries. It .ceases when the cysts are ruptured by firm presSure applied through the rectum walls. Diseased Conditions Alternatively, the ovaries may be affected with cancerous growths tuberculosis, etc., or have become so filled up with scar tissue from old corpora lptei that there is no room for the ovk to develop. Such cases are incurable and the suspects only fit for fattening. Inflammation of the uterus (womb),' whether the result of contagious abortioh, of infeetion following calving, or retention of the cleanings, is a frequent cause of cows holding to serviee. It may be recognised by a cOUtinuous and copiou3 (lischarge from the vagina, or by a slight discharge at irregular intefvals, or at the heat periods. Trouble, again, may be caused by the closing of the entrance to the uterus by scar tissue formed as the result of injury during calving. Such subjects cannot be got in calf until the parts have been "oponed up," as it is termed. Treatment comes within the province of the vetorinary surgeon, as each case needs? to be dealth with on ifcs OWn ttiorits. Briefiy, it consists of iujections of auAiseptics into the womb, irrigations, and massage; each procedure requiring expert knowledge and special equipment. An acid condition of the system oecurs in some heavy-yielding cows, and is refiected in the secretions of the vagina which on testing are found to be acid in reaction. This kills or weakens the male sperms, and may be corrected by injeeting an alkaline boIutiou (4 per cent. bicarbonate of potash in water) for several days before serviee. On the day of serviee, however, ! nothing but plain hot water should be