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THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY. [V, I
where heavy stocking to the extent of five or more sheep to the acre is continued
for any length of time, the soiling of the pastures with faeces, etc., renders a consider-
able part of them distasteful and unsuitable to the sheep.
Consequently, for the optimum benefits to be derived from improved pastures'
both in respect to nutrition and to the control of parasitism, a system of rotation
which makes it possible to practise intensive stocking for a short period and then
spelling to allow regeneration of the pasture is ideal.
In the early stages of improvement of a pasture, it may become almost wholly
a sward of subterranean clover, and lack variety and suitability from a dietetic
standpoint. Any falling off in condition of sheep as a result is very frequently
attributed to parasites, though in part it may be due to nutritional factors. In
short, it is very necessary for sheep-owners to realize that the greater the restriction
of a grazing area and the less selective feeding compulsory for the sheep, together
with an increased rate of stocking, the greater is the care and intelligence required
in management both of pastures and sheep.
ADVANTAGES OF PASTURE IMPROVEMENT FOR OUTWEIGHT DISADVANTAGES.
Notwithstanding the foregoing discussion of some of the factors which tend
to offset the benefits of improved pastures, there is no doubt that the over-
whelming body of evidence available indicates that artificial improvement of
pastures by top-dressing and the introduction of clovers and other legumes and
improved grasses constitutes a very vital factor in controlling the effects of
parasitism and in increasing production.
On the Northern Tablelands of New South Wales, there are considerable areas
where sheep breeding is no longer considered practicable owing to losses primarily
attributed to worm infestation which is at least an important secondary, if not a
primary, factor. The losses experienced, however, are almost invariably augmented
during those periods at which there is a definite lack of adequate feed available to
the young sheep, or at which, though there may be a great volume of feed, it is of an
innutritious and unsuitable nature. In these areas, we come back again, therefore,
to the importance of the nutritional factor in determining the importance of worm
infection, and it appears that there must be an increasing area permanently classed
as unsuitable for sheep breeding—with the consequent loss to the industry and
the individual—unless some means of overcoming parasitism at least is developed.
Until effective methods of control of the various important varieties of internal
worm parasites are available, pasture improvement in high rainfall areas appears
to offer the solution, and it is to pasture improvement that we must look in the
future for the likelihood of not only arresting the present deterioration due to increase
parasitism caused by under-nutrition but also of enabling a far greater production
to be reached than ever before. Even in the lower rainfall areas, as the North
Central-Western slopes of New South Wales, where the more ordinary methods of
pasture improvement offer considerable difficulties owing to soil and climatic factors,