STOCK PARASITES.

Waikato Times, Volume 121, Issue 20278, 21 August 1937, Page 26 (Supplement)

STOCK PARASITES.

TROUBLE WITH WORMS. METHODS OF CONTROL. (No. 2.) The large stomaoh worm differed from the small Intestinal parasite in that it was less refractory to the action of anthelmintics and could be effectively removed by drugs such as carbon tetrachloride, bluestone, bluestone and nicotine, and least of all tetrachlorethylene, explained Mr V. G. Cole in a paper on stock parasites at the New Zealand Grassland Conference. 'Consequently medicinal treatment against this latter parasite should be considered of primary importance.

Heavy expenditure by graziers on the purchase of drenohes often gave them a false sense of security, in that they relied almost solely on the efficiency of the drench to control the parasites, with the result that hoggets died beoause the treatment didi not remove the heavy rate of infestation to which they were often exposed or compensate for the under-nourishment which lowered their resistance to the invading parasites. The advantages of pasture Improvement far outweighed the disadvantages, and it was a vital factor in controlling the effects of parasitism and in increasing production. For the greatest benefits to be derived, both in respect of nutrition and control of internal parasites, a system of rotation, which made it possible to practise extensive stocking for a short period and then spelling to allow regeneration of the pasture, was ideal.

“ Hospital” Paddooka. Resorting to sown pastures as a means of overcoming the effects of parasitism often resulted in one or two Improved grass paddocks becoming “hospital” paddocks, which were danger areas for youfig sheep. For example, it was often the practice to have one or two paddocks which were a good source of available feed and were capable of heavy stocking. These were kept usually fairly continuously stocked by sheep which were in an unsatisfactory condition, most frequently as a result of parasitic infestation. As a result, they became fairly heavily contaminated, and when ewes and lambs or weaners, already showing the effects of parasitic Infestation, were put into the paddock at a high rate of stocking, in tho hope that the extra feed would overcome the effects of the worms, instead of picking up they died becauso the extra food did not compensate for tho mass infestation they received. However, should the change ever be made during a dry spell the results would be beneficial due to the fact that dryness inhibited tho development of the parasite to a stage when it was a dangerous menace to the sheep. In England it had been shown that two types of losses occur on arable land. The first, or least Important, was due to sheep becoming infested from a heavy residual infection which had survived in the soil from the previous season, and the second was due to “auto-infection” where sheep infected the soil from their own droppings and became re-infested. Al-

though the first type of loss could only be overcome by selecting new areas for ploughing, the seoond could he overcome by allowing the sheep to graze only small areas aft a time, oooupying one area no longer than a week and definitely not allowing them to wander baok over the already

grazed portion. If hoggets were allowed to get to the stage where they were definitely weakened by the effects of the parasites which they harboured, hand feeding would not prevent losses. Gradual loss of condition was the first clinical sign of parasitic Infestation, and if pastures were becoming bare, supple-

mentary feeding should be commenced. Where lambs had aotually begun to die great difficulty would be experienced in checking further losses, especially where lambs took time to become aooustomed to artificial method-

of feeding. ■During dry spells, creek banks and river beds were often a source oi heavy Infestation beoause sheep tended to concentrate on these areas, which usually had a green shoot, and so heavily oontamlnate the ground. Lsw-lying areas receiving drainage from hilly country provided green feed on which tho whole of the flock might concentrate and provided very heavy con-' taminatlon.