STERILITY PROBLEM.

Waikato Times, Volume 120, Issue 20889, 22 August 1939, Page 19

STERILITY PROBLEM.

Treatment of Herd Sires. Trouble Sometimes Dietetic. Sterility in dairy cows, both permanent and temporary, writes Dr. C. S. M. Hopkirk, continues to be one of the most serious disease conditions in the dairying industry. Much has been written and spoken on the subject but little can be added to that already known by the farmer who keeps in touch with such matters, but a recapitulation what we know or suspect is pardonable, and may prove of service to stock-owners. Permanent sterility arises mainly in cows which have become infected with outside pus-forming organisms after calving. Frequently this condition follows the act of abortion, the tissues being much lowered in resistance by that disease. The percentage of permanent sterility in herds is not, however, large, so little attention is paid to it. That of the temporary form is difficult to assess for it appears in a few herds in a district each season and after playing considerable havoc disappears in from two to three seasons. The usual practice of the farmer when such trouble appears is to buy in more bulls in the attempt to settle the cows, or to leave many unsettled for service in the following early spring. Such animals arc milked through for as long as they will milk, and usually that is the better plan to follow so as to place the herd on to a normal basis for production as soon as possible. The question in all minds is whether the cow or the bull is at fault. Actually there are several types of disease and one must differentiate carefully, for it depends on correct diagnosis as to the method of treatment. Conditions for Disease We can perhaps tabulate the conditions:—They are: (1) Infection of a temporary nature in the genitalia of the cow and frequently passed by the bull from cow to cow; (2) physiological upsets in the cow; (3) partial or complete infertility of the bull from disease or from nutritional causes. In type 1 a very severe inflammation occurs at the mouth of the uterus and the organism responsible can be carried at service from cow to cow. It may take a few weeks for the inflammation to subside in the natural course of events, during which time the cows comes into season irregularly because of the condition of the organs. It is in such a type of infection that the cow can be treated, and treated effectively by astringent and soothing drugs applied directly to the inflamed area. To diagnose such a condition requires instruments which the farmer does not possess, and where possible the veterinarian should be called in. There are also more dangerous conditions than just this simple inflammation, but, fortunately, in New Zealand we have come across extremely little Trichomoniasis. Physiological upset of the cow is important where seriously low phosphates are fed, or where the mineral balance is very seriously upset. Irregular bulling and complete inhibition of oestrum may result. The most important condition at present is the third. We know from rat experiments that males can become sterile under the influence of rich or incomplete diets and from the information accumulated over a number of years by departmental veterinarians and other officers it seems certain that the greatest percentage of sterility occurs through imperfection of the bull.

I can quote experiences at Wallaceville where bulla last oaly two seasons before going off and becoming in the third aenaon completely sterile. How many farmers have noticed the aaine occurrenceT A practice is growing up of using a young maiden ball for heifers, and in the second season using him in the main herd. That bull is got lid of after a season in the herd. Methods of Management What, then, is wrong with our methods of keeping the bull, for obviously there is no infectious disease associated with this condition? Firstly, the bull is kept in a small paddock and ia underexercised. The paddock is rich, as all the small paddocks round the house are, well topdressed, and with a good sward. The pasture is very rich from the protein point of view and and is consequently unbalanced. More carbohydrates are required, and in some cases more mineral, particularly lime. If the bull be poorly exercised and too well fed on a narrow ration, what can we do about it? Many farmers cannot exercise the bull by giving him the run of the farm, nor have they poorer classes of pasture upon which he can be turned out for the greater part of the year. Therefore, a different system of feeding is required. With that in view a large bull feeding experiment is being commenced at Ruakura to find whether under systems of hard feeding on pasture the fertility of the bull can be conserved. Examination of the semen of bulls is now a function of the departmental laboratories, and although it is not a perfect service, much advantageous information can be gained by the dairy farmers. Many farmers are looking to artificial insemination to help them in their breeding, but the technique of insemination is not nearly as perfect as the Russians would have us believe, and is only giving moderate success even with the most fertile of bulls. Where a storm of sterility is occurring in a herd artificial insemination is entirely unreliable. The farmer who breeds his own stock, buys in maiden bulls or bull calves which are not kept constantly on the best paddocks, and who practices a rotation of varied topdressing, including lime, gets less breeding troubles in his herd than the one who is careless in buying and relies constantly on superphosphate.