PARASITES IN SHEEP.

Otago Witness, Issue 3882, 7 August 1928, Page 12

PARASITES IN SHEEP.

The annual toll exacted from the sheep farmers of New Zealand by animal parasites is still a very heavy one, and, as may be expected, is more severe when climatic conditions are favourable to the life of the parasites. Predisposing factors cannot be ignored, and may help to explain why in some years there is a comparatively low death rate v bile in others it is excessive. Tit dry weather is hostile to some extent to the parasites, which seem to thrive when there is undue rainfall and a growth of grass unusual for the time of the year. This grass is generally of a poor, innutritious quality, and is unsuitable for sheep, particularly hoggets. Where older sheep, wethers for instance, will resist infection we find that young sheep readily succumb. Sheep are naturally the inhabitants of the dry, cold climate of. mountainous regions; their whole animal economy is suited to such a life. If they are compelled to live on watery vegetation which has, in a measure, but little nutritions value, we find that much of the food is passed in an undigested condition, and young animals in particular are much weakened and predisposed to any disease of a parasitic nature. Young animals have not the power of resistance enjoyed by the older ones. It is an accepted fact that such is the ease, but especially in sheep during the first year of their existence. They have a double function to perform. Not only have they to consume the food and energy necessary to repair the ordinary waste of tissue and energy, but they require to grow—that is, build up tissue and store energy. Well-bred, longwoolled sheep attain maturity early, and thus an extra tax is thrown upon their systems. It is a well-known fact that all the lower forms of plants and animals thrive where stagnant pools and swampy places prevail. Weakly animals will gather about these wet places and eject mature parasites from the lungs or bowels, wM”li are thus in the best position to gain fresh entrance into other lambs vvnich probably have been more or less impaired in their general health from living on land possibly poorly drained and yet in an unusual growthy season, providing feed of very poor quality. Of course, we cannot overcome the climatic conditions, but a more serious attempt should be made to render the young animals able to resist their unfavourable environment by a suitable and nutritious diet. Generally speaking, the drier the ground the better the health of the sheep. One should endeavour to prevent the onset of the disease by keeping the sheep in good heart and fettle, by feeding something in addition to the questionable vegetation in sight if the climatic conditions are untoward, in order to ward off the ill effects of parasitic invasion. Where parasitic trouble is well established in a flock, the best method of treatment is simple, yet if properly carried out is, according to a veterinarian, remarkably efficacious. The sheep should be placed upon the driest paddock available, and given one or two good feeds daily of dry nourishing food. Oats are of special value, and about six ounces of crushed oats per sheep per day, combined with good sound hay or chaff, will soon'bring about a rapid improvement. A useful adjunct is salt placed in the feeding troughs, or the sprinkling of a salt solution over the dry food. This will suit sheep affected with either the lung or stomach worms, and properly given will soon bring about a noticeable improvement in the health and condition of the animal.

A disease which in many repeats is similar to braxy occurs at times in the South Island among sheep which are fed on turnips, and takes an annual toll. Dry feed and a run-off on to tussock or grass help to stave off the disease somewhat, but deaths among hoggets have proved difficult to check. It was found that the disease was due to a specific living organism which gains entrance to the system by some means. The destruction- by fire or burial of

the carcass of an animal dying of the disease is recommended as a means of avoiding contamination of the soil. The practice of skinning the dead animals and allowing the carcass to be torn by dogs, etc., cannot be too strongly condemned, as it is by these means that the germs of disease such as this are spread, not only over parts of the same paddock, but over neighbouring fields. It is interesting in tne foregoing connection to note from the latest field report made by the Department of Agri<■’?’«u- voterir-r’pn station'’:! at Hastings,' Haw’ke’s Bay, that those farmers who have diligently attempted to overcome the liver-fluke parasite, and consequently the braxy-like disease affecting sheep in the fluke-affected area, have this season experienced a very small mortality. Many farmers, on the other hand, who have not been able to drain their swamps or drench their sheep have already had considerable losses. The fact that the braxy-like disease has been so easily controlled by ridding the farm of liver-fluke is proof of the correctness of the view advanced that the fluke is the carrier of the disease organism into the liver.

A successful trial in lowering the expense of treating sheep for the adult fluke has recently been made on a large Haw’ke’s Bay sheep station with a mixture of paraffin oil (4 parts) and carbon tetrachloride (1 part). This mixture of oil and drug, which is easy to administer, as well as cheap to buy, may be procured in one-gallon tins at a cost of 15s per gallon, this amount being sufficient for 800 sheep. It is necessary to buy one or two 5 c.c. syringes, without hypodermic needles.