DAIRY HUSBANDRY

Wairarapa Times-Age, 22 June 1939, Page 3

DAIRY HUSBANDRY

DISEASES OF MILCH COWS LECTURE BY GOVERNMENT VETERINARIAN. SOME PRACTICAL ADVICE. A lecture on “Diseases of Milch Cows” was delivered in Eketahuna recently, at a meeting arranged by the Farmers’ Union, by Mr M. C. Armstrong, B.Ag.Sc., B.Vet.Sc., a graduate of Lincoln College on the agricultural side and later of Sydney University. Mr Armstrong is a member of the Agricultural Department Veterinary staff, now stationed in Masterton. Mr Armstrong said he would not deal lengthily with each disease, but hoped his observations would be of practical value. All he had to say was from very recent research. Decreasing disease in the herd was a direct method of decreasing costs of production and increasing milk supply and carcase values. TUBERCULOSIS. “Tuberculosis,” Mr Armstrong observed, “is a contagious disease. The particular organism is fairly prevalent in New Zealand. The Wairarapa is less affected than Taranaki and the Waikato, though there are spots where there is quite a lot of it. Eketahuna might have a good deal of it. Tuberculosis, if in the herd, spreads by infection from gland to gland and from organ to organ over the whole of the beast. If a cow has it in only one spot there is a possibility of it appearing in the milk, even if it be only in a lesion in the head. It is thus a danger to the farmer’s family. It is the general idea that thin cows are the most susceptible but this is not so. Fat cows are just as prone. In killing at the Waingawa Works 90 per cent of very thin beasts were quite free. T.B. can be diagnosed definitely only by tuberculin test, though a large lump on the neck or a tumour on the hip would probably mean infection; or if a cow is very poor and coughing it is pretty certain to have it. The test is applied by the Government veterinary surgeon.” Mr Armstrong said he had known remarkable cases of the eradication of the disease. In a herd in Australia the first test showed 40 per cent of infected cows. At the time the owner could not afford to dispose of them but he had two milking sheds and kept the infected cows isolated. The next test showed 20 per cent and in six years it had dropped to nothing. His farm was isolated, there being roads on three sides and a river on the other. He bred within the herd and all heifers were tested. All through his talk Mr Armstrong stressed the point that farmers were very short-sighted if they replaced carelessly. To “look for something fairly cheap” was bad policy and they should not buy unless the stock was certified. If buying they should put the stock in a quarantine paddock. Chain harrowing and spelling of pastures checked disease. A lot of bacteria could hide in dung, but when it was exposed to the fresh air they were destroyed.

CONTAGIOUS ABORTION. The great problem of contagious abortion had to be accepted in New Zealand, Mr Armstrong continued. Chemical treatment was absolutely useless, though irrigation of the vagina was helpful. The germ, which was very widely distributed, was picked up by the mouth, then went through the alimentary canal to the udder where a lesion was formed' and it lit up in pregnancy. It was lucky for the farmer that after the cow had aborted once (or twice) it developed immunity. Storms of abortion occurred in herds. There might only be one then and no more until the new heifers picked up this infection and constituted themselves a potential danger. When cows calved farmers should keep a maternity paddock and all cows showing signs of calving or aborting should be kept from other cows for six weeks. If introducing new cows they should take a sample of blood and have it tested. They must be prepared for storms at the start. If a cow picked up the organism very early in pregnancy it would abort, but if at six or seven months it would carry through. In the maternity paddock the membrances and foetus should be buried. MASTITIS. Farmers had more or less to accept mastitis also. It was a great scourge in New Zealand and there were many different types. It was no use getting vaccines, as those for one type might not suit another. Mammitis was an inflammation of the udder. Infection through the teat canal is common the active agent being the milking machines or the milker’s hands. Healthy cows in some cases become infected by contact with a diseased cow. Susceptible cows are often infected as a result of an udder injury, such as is common after using milking machines, working on a vacuum over 141bs. per square inch or by badly fitting and tight cups. Delicate tissues were destroyed by some milking machines. mers should see that the cups fitted properly and the vacuum was not too great. One weapon which the farmer had was the indicator test. The whole outfit only cost 5s and he could go through ail the cows. There were four tubes, for milk samples from each quarter. A couple of drops of fluid was put into each tube and the trou-ble-free quarters showed yellow milk and the mastitis-infected green. The green reacters should be milked last. Any quarter showing signs of heat should be massaged and stripped regularly. The acute stage lasts only a short time and if treated the quarter does not become hard and chronic. The work was tedious, but worth the trouble. There were 3 or 4 drugs that were very useful. At a certain strength they were injected through the udder till it was fairly tense, left for five minutes or so, milked out, repeated and left for twelve hours. There was often a 100 per cent cure if the remedies were used early enough. MILK FEVER. There was a lot of trouble at calving time through milk fever and grass staggers, serious conditions that caused a cow to go down. Milk fever was not a disease but a disturbance in metabolism. It was caused through a sudden drain on' the blood calcium. If a cow were milked right out the drain might be too great and’it might go down. It| should not be milked out right away, but gradually. If the calf is taken away the first week the cow should not

be milked right out. If the cow did get it an attempt should be made to stop the drain by inflating the udder, not too hard (it should be tense) and the tapes should not be tied too hard round the teats, The other way was to put calcium into the blood, but a veterinary surgeon would have to do that. OTHER DISEASES. Acetonaemia was a condition involving disorganisation of the functions of the liver which could not break down the by-products of the carbo-hydrates. It was similar in symptoms to milk fever from which it was differentiated if the cow did not respond to calcium. The treatment waS to inject dextrose. A cow suffering from eclampsia lies down; usually it has convulsions and its head is twisted. It is cured with an injection of calcium (not magnesium and not dextrose). It was very difficult for the ordinary farmer to differentiate these after-calving conditions and elimination was often the only way. ' , In the case of grass staggers, the cow was attacked just before or just after calving and a high stepping action was a symptom. The cure was by injection of magnesium into the blood. Asked whether he thought that calcium could be supplied by top dressing pastures with lime or with tricalcic phosphate, Mr Armstrong said it was an excellent idea to lime pastures regularly, but he did not like the tricalcic as it contained fluorine which caused poisoning and decay in teeth if stock grazed shortly after the topdressing. Farmers whqtused licks were not so much affected. A lick that was cheap and could not be bettered was a 50-50 mixture of salt (ground rock salt) and bone meal. lodine was not necessary. In New Zealand, Mr Armstrong replied to another question sterility in cows was caused by the after effects of abortion and infections of various kinds- In isolated cases it was caused by tumours and cysts in the ovaries. Mr Armstrong concluded by reiterating his counsel only to buy good animals, after which a hearty vote of thanks was carried by acclamation.