PARASITES OF SHEEP.

Otago Witness, Issue 2996, 16 August 1911, Page 16

PARASITES OF SHEEP.

Mr T. H. Williams, Acting Chief Inspector of Stock, South Australia, -writes in the Adelaide Chronicle: Has it ever occurred to owners or managers of sheep that there is a heavy animal loss through their neglect to dip the animals and destroy the parasites on them? There are probably quite 1000,000 sheep infested with lice in the State to-day, and it is a low estmate to say that by biting, scratching, and rubbing each animal loses 21b of wool annually. At a low estimate of 6d per lb this represents £50,000. The unthrifty and stunted condition of the animals, and the deteriorated state of their wool—worth only about 3d' per lb—means another annual loss of anything from £IOO,OOO to £120,000. The annual loss to owners as the result of allowing sheep to remain tick-infested probably represents quite another £IOO,OOO. These are large accounts to lay at the door of negligetnt management, when for an outlay of about 2d per head sheep can be dipped in the best poisonous powder dips on the‘market and the destructive parasites destroyed. Unfortunately there are many who market their sheep immediately off shears, undipped. Dealers or farmers get them, and they are spread all over the State. The buyers probably know nothing about lice, and cannot understand why the sheep do not thrive.. A neighbour is consulted, and he and the owner conclude the sheep have some mysterious disease. It is the duty of everyone interested in the care and management of sheep to examine them frequently and see that they are free "of parasites. There is a point which must be impressed upon, those who dip their sheep, and that is that no carbolic or non-poisonous dips will render the sheep immune to the attacks of parasites, while the best poisonous powder dips will protect them for months. When the lice are present on sheep at shearing they must be dipped in poisonous powder dip off the she,ars, and again at the end of two months, as it always required two dippings to free animals of lice.

Sheep from infected districts have, unfortunately, spread lice to many thousands of our northern flocks, where merinos have become infected, and some recently inspected had' lost nearly half their wool. It would probably be a good idea for owners of sheep in, infected areas to form vigilance committees and satisfy themselves that all sheep are dipped every season in. approved dipping powder. _ The lice are very minute—less than l-16in long—and difficult to see. They are pink in colour, when gorged with blood, and lie close to the skin of the sheep. When a few are seen on opening the wool it is generally sufficient evidence of the presence of thousands on the animal examined. A low-power lens will aid in the search for them. They multiply rapidly, the eggs being deposited at the roots o f the wool, where they are hidden by particles of yolk, etc. The embryo, being surrounded by a protecting greasy substance, is not touched by the dip. Hence the urgent need for a second dipping to destroy the young lice. *