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This article was published in 1955
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INSTITUTE OF INSPECTORS OF STOCK OF N.S.W. YEAR BOOK.

DISEASES ASSOCIATED WITH DROUGHTS

E. A. FARLEIGH, B.V.Sc., Inspector of Stock, Glen Innes-Inverell.

At the present moment droughts are far from our thoughts, but we have only to think back a few short months to recall that we were then in the grip of a very dry spell; when stock were short of feed throughout most of the northern areas of N.S.W.

It is interesting to summarise various disease conditions which were encountered during the second and third quarters of 1954, and to connect them in no small measure to the lack of feed at the time.

One of the commonest conditions seen was worm infestation in sheep; particularly in weaners. Anaemia, weakness and death were being investigated continually, and in nearly all cases Trichostrongylus spp. (Black Scour Worm) and Oesphagostomum columbianum (Nodule Worm) were found in large numbers on post-mortem.

Why should these infestations be attributed to a drought? The first explanation is that weaners, having a higher nutritive demand than older sheep, are the first to show the effects of any parasitic burden. Secondly, at the time hand-feeding in troughs and self-feeders was practised widely and as the feed gradually cut out in the paddock the sheep congregated within a small radius of the feeding sites; with the result that there was a heavy overstocking of those areas, and consequent increased chances of re-infestation. Satisfactory control could be obtained only by changing the site of the feed troughs; if it were not possible to change the paddock in addition to drenching.

Liver Fluke on the higher country also caused a number of deaths, even up to 10% of flocks on many properties in these cases sheep fed along the course of streams and around swamps, as these areas were the only ones where a green pick could be found. Young Fluke were being picked up faster than they could be controlled by drenching; which became effective only when the danger areas were fenced off and other water facilities provided.

The period approaching lambing in the spring presented another problem in breeding ewes. The disease known as Toxaemia of Pregnancy caused a heavy mortality in ewes within a month of lambing. The sheep at this stage were on a rapidly falling plane of nutrition on natural feed and in many cases hand-feeding was insufficient; which adds up to one of the commonest predisposing causes of this disease.

It is not proposed here to go into a description of Pregnancy Toxaemia, except to stress that treatment is generally unsatisfactory and that, as with most diseases, this one is a typical example of the old axiom that "prevention is better than cure". Only by increasing the food intake at this critical time before lambing can this condition be controlled. One owner lost 35 ewes in a mob of 200, which indicates the serious economic loss which can result if adequate precautions are not taken.

With the lack of green feed stock lose their usual selective feeding habits and will eat anything that might provide them with some bulk. This craving for food produces a great danger of poisoning and is usually more noticeable in travelling stock. Losses from eating poisonous plants, such as Crown Beard, Mint Weed and even Variegated Thistle have been encountered; these losses being serious and at times hard to avoid. One case was seen in which poisoning resulted when the owner fed baled lucerne hay of second grade quality, which contained a considerable percentage of Crown Beard, or, as it commonly is called, Yellow Daisy.

It is necessary to use a considerable amount of common sense with handfeeding. Sudden high intake of grains can be disastrous to hungry sheep and all stock should be introduced to hand-feeding slowly, and with a gradual increase in the amount of feed given. Roughage should be fed before nuts or grain, especially if the sheep are not used to them. One of the commonest faults seen in hand-feeding was that the amount of troughing was inadequate for the number of sheep; resulting in the strong sheep getting stronger and the weak sheep weaker.

A decrease in the fertility of stock also has been seen, particularly in cattle. It has been established that female cattle go through a period of anoestrus under drought conditions and there were many reports of cattle failing to conceive.

A considerable sum of money was spent by many landholders in supplying Vitamin A supplements to sheep during this dry spell. Much of this money was wasted as research has established that Vitamin A is not depleted in the body until the animal has been without any green feed at all for a period of at least five months. As droughts on the Tablelands seldom exceed this period without some beneficial rain, it is considered that such dosing with Vitamin supplements was not warranted, and certainly was not economical.

From this brief account it must be realised that there are many problems associated with the successful management of stock over a dry period; and that it is not simply a matter of feeding and hoping for the best. If a stockowner is conversant with the problems that are liable to confront him, then he is in a position to save himself considerable economic loss, and at the same time bring his flock through the crisis and so reap a just reward for his forethought and capable management.


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