DISEASE IN DAIRY COWS

Taranaki Daily News, 17 October 1930, Page 12

DISEASE IN DAIRY COWS

THE RAVAGES OF ABORTION

VALUABLE HUNTS TO FARMERS.

VETERINARY EXPERT’S ADVICE.

Information of value to farmers was conveyed in a lecture at Okato on Wednesday night by Mr. Hill Motion, veterinary surgeon engaged by the Animal Health Committee. Mr. Hill Motion took for his subject contagious abortion. It was a disease, he said, that was chronic. It was only when a cow. slipped that a farmer considered there was abortion in the herd, but the fact that a cow aborted did not show that she was suffering from contagious abortion. Teste might show that a large, percentage of a herd might be infected with contagious abortion whereas probably very few of the cows might abort. He stressed, the losses caused by abortion which meant first the loss of the calf or the birth of a. weak calf; secondly the loss of milk estimated at one third of the total yield for that season. Thirdly there was also the danger of other diseases following, including sterility. The spread of infection was very important. Older cows developed; a sort of tolerance to the disease and as long as another strain of organism was not introduced the herd might go on all right for years, except pex'haps the young stock. In cases where stock was sold on 'blood test there was considerable loss in the saleable value of the cows. Iri New Zealand, too, there was loss due to cows coming into profit at wrong seasons. It seemed strange that after many years of research it was not possible to discover a cure, but he suggested ways in which fanners could hefp themselves. He enumerated various organisms that induced abortion, including tuberculosis and foot and mouth disease. Moulds in the food eaten had been shown to cause abortion. Mr. Hill Motion pointed out that farmers- were apt to lose sight of the disease by considering only t’he cows that aborted whereas blood teste might show that there, was perhaps 50 per cent, of infection 7 in the herd. He showed, how to take the blood test, remarking that it was in most cases a'ble to give a definite possible or negative result. The blood test should be taken about three weeks after calving or abortion. . One. test was not sufficient; three should betaken. A cow that was reactive was not always a reactor. Mr. Hill Motion said that- it was usually a pregnant cow that brought the disease into the herd, as the disease was sometimes due to an animal being sent on to a farm that was already infected. The most important method of infection was injection—by the mouth either from the pasture or the water. Physical contact was necessary for infection, and he thought they could rule out such things as carrying it by the boots and clothes. Infection was not likely to be so great where cows were kept stalled for a few months in the year. Some authorities in America considered that mammitis soon after calving wa.s due to abortion but that had yet to be definitely proved. From the farmer’s viewpoint the most important aspect was the question of control. It was an important disease but despite the fact that for the past 35 years the brains of the best scientists had been at work on the problem nothing had been achieved that could definitely help the farmer. The larger herds were more prone to infection as with the smaller herds a farmer generally bred his own stock. The Government could assist in controlling the disease. It could help by .giving the blood test free of charge. It could also introduce an order preventing the exposing of infected stock in any public place. That was done in one or two countries now.

There was certain gross carelessness on the part of some farmers that required checking. Where state mntrol was introduced there was also the question of compulsory slaughter, Which was not possible in New Zealand. Other important pointe were how to keep infection from a clean herd and the elimination of the disease from an infected herd. Regarding the former it was first necessary to be certain that it was in the herd, and the only way to do that was to test at least twice. Having ascertained that the herd was free tne best way to keep it free was by breeding one’s own stock, which was not always possible, and by keeping stock on one’s own farm and not allowing stock from other farms on the property unless certain those farms were clean. Mr. Hill Motion said he knew that certain farmers sold every cow that aborted and introduced others that were likely to abort, but as. 75 per cent, of the cows that aborted once did not abort again, it was preferable to keep the cows that had aborted. If lists revealed a very small percentage of infection is was advisable to isolate those cows on a remote portion of the farm and let them rear their calves; otherwise it would be necessary to divide the herd into two sections, which was not always possible. If the infection was as high as 50 per cent, the herd

if there was 75 per cent, of infection it Would be advisable perhaps to sell the cows that were not infected. He pointed out that the calves reared from the infected cows that had been segregated could clean. Vaccination had been tried in most countries but had not ‘been proved to be successful. The idea of using living vaccine was to endeavour to cause an infectious immunity constituting the “tolerance” already mentioned. Replying to a question Mr. Hill Motion said that infection dropped, on tlffi (pasture would not last mo're than a month.

Mr. Larking said that he had fed. out some mouldy ensilage to his stock and that had been followed 'by several cows aborting. Mr. Hill Motion said it had only recently been discovered that eating mould was one of the causes of abortion. It could only be definitely ascer-,-tained whether or not infectious abortion was the real trouble by taking the blood test.

(i A discussion followed on various problems affecting the management of stock.

' , Subsequently, Mr. D. Le Oren Morgan, secretary of the North Taranaki executive of ■ the Farmers’ Union, urged all farmers to link with the veterinary scheme which, he stated, provided a grea.t free service for farmers. He recognised that at the present time farmers must conserve their finance, but they should regard linking' with the scheme as an insurance against loss of stock.

The Government, said Mr. Morgan, was considering introducing a scheme of group veterinary service to be worked through dairy factories. It proposed that for a group comprising 8000 cows the charge should be, 2s 6d per cow bind for a group of 12,000 cows Is 8d per cow, providing it was to pay the salary of a qualified veterinary surgeon. In addition, medicines would be supplied at cost. The North Taranaki scheme provided that the cost would be on a sliding scale of 2s per cow for a herd of 20 cows, Is 8d for 30, Is 6d for 40, Is 4d for 60, Is 3Jd for 70, Is 3d for 80 and Is for 100 cows. Medicines would be provided free. That also included attention to horses, pigs and calves on the farm. Moreover, to meet present financial conditions the committee was prepared to accept the fee in three instalments. It could therefore be seen that their scheme was much cheaper than the Government scheme. He admitted that in order to start the scheme it was necessary to take in a rather large district but he felt certain that the scheme would prove so successful that in two or three years there would be three group’s operating in North Taranaki, as in an advisory capacity alone farmers would receive full benefit from joining the scheme.