SHEEP-SICK COUNTRY.

Auckland Star, Volume LIX, Issue 70, 23 March 1928, Page 15

SHEEP-SICK COUNTRY.

CAUSES AND PREVENTION,

THE INTESTINAL WORM TROUBLE,

(By "SUNDOWNER.")

Ever since man began to confine his domesticated animals within fences he has had to contend with a multitude of stock ills or diseases, unknown to the patriarchs who shepherded their flocks and herds on the wide open spaces. With them the stock bred and were grazed under almost natural conditions, except that they were protected from predatory animals, and under healthy conditions, with abundance of food, water and exercise there was little chance of disease gaming a footing. When confinement of the stock to small areas was found necessary a number of new conditions were set up, mcst of which tended to interfere with the atock'a natural habits, and as a result diseases gained a footing, which even in this enlightened age take a heavy toll from the farmer's profits. One trouble, or rather collection of troubles, for it has its source in several influencing factors, which still causes serious loss to farmers to-day. is "sheep sickness of land," and aB many other latal sheep diseases appear to secure a footing among the enfeebled sheep affected from grazing on this land, it is as well for every farmer to be able to recognise the condition, and take steps to prevent as well as cure the trouble amongst his stock. Symptoms. On sheej» country, however good it may be, which is continuously grazed the sheep become dull and cease to thrive. This Is accompanied by anaemia, the skin, mouth and eyelids presenting a pale appearance, due to the impover" ished condition of the blood. The sheep wander about picking at the food rather than eating steadily; they show a great fondness for willow leaves and bark and in fact almost any trees or shrubs to which they may have access. In the midst of abundant feed the sheep will go back in condition, and fattening on this land is out of the question. The chief causes of sheep-sick land are that through continuous selection of the most palatable and tonic grasses the sheep have killed out these varieties, at the same time allowing the lessattractive grasses to become rank and unpalatable; that they have fouled the gTound witft their droppings, and that they have partially exhausted from the pasture and soil those salts and minerals which are particularly necessary to their health. . The most important cause, however, is that the soil io fouled with their manure, and with the parasitic germs which this frequently contains. Worm Infestation.

This •'brings ug to that widespread but neglected evil, stomach worms, which are the direct result of grazing sheep on sheep-sick country. The sheep, unlike the horse and the pig, has four stomachs, named first, second, third and fourth in accordance with the order in which the food passes through them. The last of them is the only true stomach, since it alone corresponds with the «ingle stomach of other animals, and is concerned with the digestion of the food. It is in that stomach that the worms are found. It is a comparatively easy matter to dose single-stomached animals with drugs which will eradicate internal parasites, but with the sheep, in which the nrst of these, the paunch, alone has a capacity of at least ten times that of the fourth, and is never completely emptied even by starvation, it is obvious that a dose of medicine must be greatly diluted and obstructed before it reaches the seat of the trouble. In actual fact, a dose of medicine sufficiently strong to kill the worms when it reached the fourth stomach would undoubtedly kill the sheep in getting there. Briefly, medicine given by the mouth may be practically ruled out as a possible cure for stomach worms, excepting in the case where it can be given in small regular doses in the foods, or, for preference, in the ordinary drinking water, which takes a more direct passage to the fourth stomach than does medicine applied in a drench. Life Cycle of Stomach Worms. Medicine having' been proved practically useless in treating this trouble, veterinary scientists made a study of the life history of the stomach worms of sheep. It was found that the eggs from the worms did not incubate in the sheep's stomach or bowels. They must be excreted by the animal, and on the soil or pasture the hatching of the eggs is usually completed within a few days. After the embryo worms have attained a certain stage of development they are ready to be taken in by sheep with food or water, usually the former. As soon as these young worms reach the fourth stomach the final stage of their development into the adult male and female parasites is begun. There are several important points to be noted in connection with this life cycle. (1) That an ordinarily well-nourished sheep can support some hundreds of these parasites in its fourth stomach without evidence of ill-effect. (2) That the worms cannot incubate their eggs inside the sheep. (3) That the yoiffig worms do not reach sexual maturity outside the sheep, and therefore cannot breed and multiply unless they can find their way back to their host, the sheep. (4) That these parasites may retain their vitality outside the sheep's body for a period that varies considerably, but may extend to months under favourable conditions. Treating the Country. This may appear to be a digression from sheep-sick country, but it is not, for it is chiefly through the infestation of the land with these stomach worms that country becomes sheep-sick.* Owing to the great difficulty of achieving success in treating the adult worms with medicine, it is obvious that the best plan to adopt is to treat the country from which the immature worms are waiting to be taken up by the sheep. This may be done by three methods—by spraying the pasture with some mixture which would kill the germs and not the grass; by burning off the grass at a favourable opportunity; or by removing all the sheep from the land for a considerable time and grazing it with stock which would not be a congenial host to the worms. The last method is undoubtedly the simplest, cheapest and most effective, for it has the added advantages that the landj while being treated, is still producing, that the pasture grasses favoured by the sheep will hate a chance of re-establishing themselves, and that the droppings,-which make the pasture distasteful to the sheep, may have ft cft&nce $o becomg dissolved and incorporated

with the soil. Graziruj with cattle during the time the country is spelled has the adflea advantage of bringing the coarser rough grasses into a condition where the sheep can thrive on them. Subdivisions Essential. In order to cure "sheep-sick" country it is essential that there be sufficient subdivisions on the farm to enable each paddock to be spelled in turn for a considerable time. A week or two is not sufficient. At least two months grazing with cattle or other stock should be allowed each paddock before the sheep are returned to it, and in mojst climates even more might be necessary. It is pleasing to know that while rotational grazing will prevent sheep becoming worm-infested and land becoming sheepsick, it also has the advantage that the animals are more healthy, because of the added exercise which roaming round their new quarters give them, that a better mixed pasture is maintained, and more stock can be carried on the same area than where the stock are carried on one block throughout the season and disturbed as little as possible.