FARM.

Northland Age, Volume III, Issue 20, 27 May 1931, Page 7

FARM.

CONTAGIOUS ABORTION OF '^|COWS. The season is approaching when this disease makes itself most apparent, through the fact that some of the affected cows abort their calves. With that in mind, these notes are written as a reminder to larmers of what they can and should do to combat the trouble. Contagious abortion is due to infection with a particular species of microbe, which tends to l locate itself between the wall of the womb and the membranes in which the unborn calf is wrapped. It is the damage it causes in this situation which results in abortion. The principal way in which the cows and heifers pick up the infection is by grazing over pasture t)M has been contaminated wiih the germ. Obviously then, trie discharge from an aborting cow and the aborted calf and its membranes are the serious source of pasture contamination and hence of infection passing to other cows. This brings us to a very obvious and important precautionary measure which it behovjs every farmer to take. Almost all cows that are going to abort show signs for some hours, sometimes longer, beforehand. There is usually restlessness, often accompanied by bellowing, and as a rule closer observation shows the swelling and slackening of the passage, just as occurs before a natural calving. If the cow is in milk, as most will be at this time ot the year, a marked and sudden drop in yield and a tendency for the milk to take on a consistency like that of the colostrum (or first milk after calving) is frequently seen. Sometimes too, there is a brownish discharge from the passage a short while before the abortion takes place. When^WFthese signs are seen and a farmer should regard it as . his duty to see each pregnant animal at least daily (from a spot close beside her, not a casual glance from the paddock gate) the beast should immediately be removed into isolation. There is always some place on a farm where this can be done, such as an orchard, and the animal should be left there until the discharge has ceased and tor six or eight weeks after the date she actually aborts. If, in spite of close observation, abortion occurs in a paddock among the other cows, the aborted calf and membranes should at once be collected and either burnt or deeply buried Any discharges found in the paddock should be collected too,'and the ground contaminated by these means heavily sprinkled with, quicklime. Isolation of the offending cow is equally essential of course, in this case. Another common method by which the abortion germs are spread on pastures is through the fact that a percentage of infected cows discharge numbers of them from the passage, although they calve at full time, or thereabouts, and are not suspected by their owners vof being abnormalHence, alP'cleanings” should be collected and destroyed. This will help to no small extent. It is only when the womb is ? pregnant that the germ of contagious abortion localises in it. In non-pregnant cows it attacks instead. Many infectarr >' the germ in their ear, and they may jo the womb w s are ‘ n an, H H: wk

time, and with the subsequent discharges, as quoted in the last paragraph. The result of this chronic infection ot the udder is a very slight degree of inflammation, too slight to be observed with the naked eye in most cases, but enough to cause a reduced milk yield, and, moreover, an udder that is infected in this way is probably more susceptible to other troubles, such as the more obvious forms of mammitis. The bull is sometimes infected but seldom plays as important a part in spreading the disease as an aborting cow would do. Calves are not susceptible to the disease, but it fed on infected milk the germ is spread through its presence in their droppings and it is therefore desirable that whde the calves are being fed on milk they be kept in a paddock by themselves. When it is necessary to remove them the paddock should be given a rest, or eaten out with sheep or bullocks. At the age of nine or ten months young stock become highly susceptible, especially a female which becomes pregnant. (To be Continued)