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This article was published in 1966
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INSTITUTE OF INSPECTORS OF STOCK OF N.S.W. YEAR BOOK.
What have We Learnt from the 1965 Drought?
P. McINNES, M.Sc., Veterinary Research Station, Glenfield
INTRODUCTION
Before attempting to study the lessons which have been learnt from the 1965 drought, it is necessary to compare briefly the progress and distribution of this recent drought with droughts previously experienced in New South Wales. By relating descriptions and comments of Foley (1957) with sheep populations (Anon., 1961), the 1965 drought can be compared and contrasted with other droughts in N.S.W. which have caused sheep losses of greater than 10 million.
The drought of 1902 was preceded by approximately ten years of decreasing stock numbers. During 1896-1900 sheep losses in the Western Pastoral Country were 4 million. During 1902 losses were most severe and widespread throughout N.S.W. A total of 15 million sheep were lost and few of these were from the already depleted Western Country. Both the 1919 and 1944 drought were similar to that of 1965 in that sheep numbers had been steadily increasing during the immediate years before the drought. The drought of 1919 and 1965 were very similar as the areas affected were the North Coast, Northern Tablelands, North Wheat Belt and Western Pastoral Country. The drought of 1946 had more of a southern incidence.
As droughts may be dissimilar in their progress or may spread in different directions, there are certain limitations in the application of any knowledge gained during the course of the 1965 drought. The year 1965 heralded either the first of many years of drought or it was a year in which a drought of approximately one year's duration occurred. No doubt if the drought continues in 1966 some of the drought strategies would be replaced by policies which are more applicable. The decision whether to feed or sell stock will certainly be one of the factors which will be reconsidered.
DROUGHT STRATEGIES
What drought strategies were used during 1965? Many farmers especially in the Western Pastoral Country, sold varying proportions of their flock. Improved transport gave an opportunity to market sheep in a store condition and this partly aided market price to remain relatively high. There were examples of panic selling at low prices, especially in the Northern Tablelands, where problems associated with wheat feeding often occurred.
Many reports of sheep agistment were received, but it is difficult to accurately measure the number, as usually private arrangements are made in the transfers. It was evident that agistment provided a cheap source of feed. Often unstocked properties, which were on the market for sale, provided cheap grazing.
Frequently farmers delayed feeding and relied on "the breaking rain". In these circumstances occasionally sheep were allowed to fall too far in body condition, and then given too little feed too late. Many deaths occurred in cases when these sheep were fed too large a quantity of wheat.
The practice of feeding too early was evident in many areas, especially where the effects of the dry period were not as severe. Substitution feeding therefore often occurred, while the available pasture deteriorated in value. Unfortunately it was hay or oats which was often wasted in this fashion.
EFFECTS OF LIMITED WATER RESERVES
Lack of water in many districts had two significant effects. It prevented the utilisation of dry pasture of fair-poor quality. It was not an uncommon occurrence for part of a property to contain standing dry pasture, while in other parts stock were being totally hand-fed. Lack of water also often prevented total hand-feeding in feeding units, as often it was not possible to transport the water at an economic cost.
Unfortunately little has been learnt during the drought of the quantities of water which are required for stock. There are obvious difficulties in determining an estimate because of evaporation losses. Experiments in pens have shown that water requirements increase as fibre content of the diet increases. Approximately two pints of water are required per lb. of wheat, three pints per lb. of lucerne and five pints per lb. of poor hay. Requirements during pregnancy increase by approximately 24 times from the first till the fifth month.
Additional information is required on rate of evaporation from dams, the minimum water requirements when different levels of grain are fed and the type of water troughing required for minimum water loss.
Another important factor which must be considered in watering stock during a drought is the dangers associated with low water levels. Salt poisoning was experienced during 1965 - levels of salt higher than 1 per cent were not uncommon. Algae poisoning was also reported when water levels were reduced.
THE TIME TO COMMENCE HAND-FEEDING
There were obvious difficulties associated with selecting an optimal time to commence feeding. In most cases that nebulous character, body condition, was the main criterion used. As there was variation in body condition within flocks and because management limitations preventing separating the stronger from the poorer conditioned sheep, often some sheep in the flock were in such a physiological state that, when hand feeding did commence, they were unable to consume sufficient energy from a survival ration.
There were difficulties in assessing at what levels supplementary feeding should commence. Changes in body condition were used as a criterion in assessing the nutritive value of standing pasture. While this practice provided a good guide for experienced farmers, for others it seems obvious that body weight measurements will be in the long run the only satisfactory guide to indicate accurately the level of supplementation.
THE VALUE OF BURR
The value of medic burr was quite conspicuous in many areas. The abundant Spring growth of previous years had left ample fodder reserves in many areas. The value of the burr residues which were often available in 1965 could be misleading if the drought continues to 1966. The presence of burr in 1965 meant that paddocks could be better utilised if low protein pasture was also present. It also meant that supplementary feeding could be delayed or at least the level could be reduced. A recent publication by Luff and Darling (1966) indicates variation in the crude protein of burr grown on different soils. Differences in burr consumption appear to be related to species and/or chemical composition.
As very little seeding of medics occurred in 1965, the effect of burr on supplementary feeding may completely alter in 1966. Already there have been reports that much of the burr present in some areas is completely devoid of seed.
THE BODY CONDITION TO MAINTAIN SHEEP
Observations during the drought strongly indicated that the body condition of sheep should not fall below store condition before hand feeding commences. In addition, it became increasingly obvious as the drought progressed that sheep unaccustomed to hand feeding should be supplemented with small quantities of grain even while they were more forward than store condition.
There is a strong feeling that flocks in the cooler tablelands regions should be maintained in a better condition than in the warmer districts. Their reserves in the form of fat should be higher to withstand environmental stresses, especially those which occur within the first six weeks after shearing.
The condition at which pregnant sheep should be maintained during a drought had previously received little attention. The drought certainly taught a few lessons! Observations indicated that pregnant sheep should be maintained in a store to forward store condition from mating to the latter part of pregnancy. This necessitated at least one additional food unit per week. During the last six weeks of pregnancy an additional food unit was usually required for satisfactory lambing. In cases where condition of pregnant sheep fell after mating, a panic attitude was initiated in the last six weeks of pregnancy: quantities of wheat were increased by 50 per cent and if scouring did not occur then a farmer often faced numerous cases of Pregnancy Toxaemia.
ENERGY REQUIREMENTS
It became apparent that survival requirement of four food units weekly for dry sheep was a good guide although it is quite likely that small frame fine wool breeds could have been fed less, while the larger framed South Australian type was probably underfed.
Observations in the colder tableland areas indicated that up to five food units was a more satisfactory level so that these sheep can be maintained at higher body weights. Losses of sheep in these areas after shearing certainly substantiates this point, as many deaths occurred up to six weeks after shearing, although the weather pattern had not altered. It has been suggested that the slow and continual loss of heat by convection caused more deaths in some areas than a rapid cold change immediately after shearing.
The levels at which wheat should be initially fed caused many problems. In cases where sheep have not been previously fed grain and little roughage is available it has become obvious that no more than 2 ozs./sheep/day should be fed initially. The interval of time required to bring them on to a daily survival requirement of 3/4 lb. of wheat should be between 20 and 30 days. Loss of body weight will occur in many cases during this period, and this is an additional factor supporting the contention that sheep should not be allowed to fall to a poor condition before feeding.
An amount of confusion has developed about the amount of wheat that should be fed to pregnant sheep in the last six weeks of pregnancy. There have been reports that a level of over six food units has caused problems of wheat engorgement while other reports indicate that this level over-estimates requirements.
These observations are no doubt associated with either shy feeders or the amount of roughage or burr present. Even if only a small percentage of shy feeders initially exist when these levels are fed, some ewes will receive more than their share. Often the shy feeder problem may revolve a complete cycle, as ewes which initially consume enough wheat to become sick and then scour will consume less during following feedings, and allow an opportunity for other sheep to consume too great a quantity. As the amount of roughage can affect the amount of wheat which can be safely consumed, many variations in observations would be associated with the quantity of dry residues.
Feeding problems were consistently encountered when weaners of 6-12 months were totally hand fed wheat. Between 3½ and four food units are required for survival for this class of stock. Little digestive disorders were reported when wheat was fed in paddocks which contained some roughage or alternatively a little roughage was fed with the wheat.
While research work had indicated that lambs could be easily weaned on to diets containing up to 50 per cent roughage, unfortunately the benefits which can be obtained from early weaning could not be realised in areas where it was not economical to purchase roughage. The most important lesson learnt therefore was that additional knowledge must be obtained on the diets which can be fed to early weaned lambs.
FEEDS AND OTHER SUPPLEMENTS
Wheat
The resistance of farmers to feed wheat was at its lowest ebb during the 1965 drought. We learnt that the resistance has to be overcome so that drought feeding can be carried out economically. There is no doubt that the feeding of wheat offset the full effects of the drought.
Hay
Hay became a real treasure as the drought progressed. In small quantities it prevented digestive upsets when wheat was initially fed. Between 25 and 50 per cent hay is required in diets for early weaned lambs. Small quantities were often used to bring sheep back on to wheat feeding.
There is no doubt that, used strategically. hay can be of a great benefit during a drought, and it seems very unfortunate that it is often the fodder which is so often wasted in the early part of a drought, so often criticised as being uneconomic to conserve, and yet so welcomed by hungry drought fed stock.
Pellets
Pellets certainly presented some of the worst traps of drought feeding. The change in composition of pellets which occurred as the drought progressed was fortunately soon recognised, but unfortunately many deaths still occurred. In the manufacture of pellets, wheat was substituted for oats, roughage content was reduced, and urea was incorporated to maintain a protein equivalent value. Changes between batches were difficult to recognise, and subsequently abrupt changes in diets unfortunately occurred.
Often weaners did not consume sufficient quantities of the larger size pellets although this problem was not reported when weaners were fed pellets similar to those manufactured for the poultry industry. These pellets are processed through smaller dies, and are more readily consumed by the younger stock.
Scrub
Little additional information was obtained during the drought on the feeding qualities of lopped scrub. At the ruling prices of labour and fodder, scrub feeding appeared economic. Cases of toxicity occurred with Rosewood and these were mainly associated with fresh regrowth or moisture on the foliage. Leopardwood seeds occasionally caused impaction while ingestion of green pods of kurrajong on occasion caused mortalities. Spraying scrub with molasses often encouraged sheep to consume greater quantities, but occasionally impaction occurred as intake of woody material increased. In many cases it was necessary to feed a small amount of wheat or urea with scrub to prevent too rapid a body weight loss.
Urea
Urea supplements were of little use in areas where medic burr was present. In areas where ample poor pasture was present, it was reported that body weight loss was reduced when urea supplements were fed. Urea was fed in many combinations, and many farmers were willing to make mixtures on their properties. Of the mixtures probably the most common made was Shepherd's mix.
Toxicity occurred when management was lax. Blocks containing high amounts of urea were occasionally fed without shelter from rain or snow. Salt-hungry sheep were sometimes given access to the same type of blocks, while there were a number of reports that toxicity occurred when the procedure of increasing urea slowly in Shepherd's mix was ignored.
Vitamin A
Although constantly under pressure from ever ready and eager commercial interests, Vitamin A recommendation "weathered the storm" and proved appropriate. No doubt further study has to be made on vitamin A such as the rate of recovery of vitamin A liver reserves.
Calcium
Many farmers failed to add limestone supplement to wheat rations, but troubles were not generally encountered with dry sheep. No doubt body reserves were mobilised to meet the deficiency in the diet. The calcium requirements of pregnant and lactating sheep are high, and even when 13 per cent limestone is fed with wheat, some reserves would be used from four weeks before lambing. Whilst the need to add a calcium supplement for dry sheep may not be necessary during the first weeks of total hand-feeding, a supplement should be fed to pregnant and lactating ewes.
MANAGEMENT
Feeding in confined areas
While there are advantages in hand-feeding in confined areas, many problems occurred during the 1965 drought. High incidence of Ostertagia, Nematodirus, and on occasions liver fluke occurred. Coccidiosis was reported often but fortunately a rapid response was obtained by treatment with sulphadimidine or furazolidone.
Troughing or trailing
Trailing fodder on the ground was a satisfactory method of feeding, except when grain was fed on black soil which had developed cracks, or on light soils which were dusty. Trailing gave the opportunity of feeding in different regions in a paddock and thereby allowed sheep a better chance to harvest a greater area of roughage. Troughing appeared satisfactory provided an economic unit could be used.
FREQUENCY OF FEEDING
Dry sheep
Twice weekly feeding was much more suitable than weekly feeding.
Daily or two-day feeding was commonly practised without digestive upsets.
Lactating ewes
Many problems occurred as ewes tended to leave lambs and mismothering occurred. Feeding at night was practised to overcome this problem and this method of feeding proved successful in most cases.
CONCLUSION
There are a few miscellaneous points which should be mentioned in conclusion. These are also important factors to consider in the role that extension can play in mitigating the effects of drought.
Some attempts should be regularly made in assessing the amount of fodder conservation in any area. A convenient index to measure is a value for "Preparedness to Drought" which is a ratio of the number of fodder units to the number of stock equivalents. A fodder unit is equal to 1 cwt of good quality hay or one bushel of wheat or two bushels of oats. Seven sheep are assumed equivalent to one head of cattle. A ratio of one for a region means that there are sufficient reserves for three months of total hand-feeding.
Considerable extension assistance can be gained by conducting "Demonstration days" on properties which are successfully feeding wheat. One cannot fail to recognise that there is still some resistance to wheat feeding. There are also many farmers who indiscriminately feed wheat, no matter what is written in booklets. During 1965 demonstrations of this type were well attended and appeared quite successful.
Finally one of the main lessons learnt during the drought was that inexperience prevented efficient measures in many situations. Officers and farmers were placed, or possibly often thrown into a position which was totally foreign. Reliance on cursory observations and off-hand accounts of previous droughts were not very helpful. It is therefore indeed fortunate that some publications will be made of the problems and lessons learnt during the 1965 drought.
REFERENCES
Anon (1961) - Statistical handbook of the sheep and wool industry. Bureau of Agricultural Economics, Canberra, Australia
Foley, J. C. (1957) - Droughts in Australia. Bureau of Meteorology. Bulletin No. 43
Luff, A., and Darling, G. G. (1966) - Medic burr - A good feed or just a vegetable fault. N.S.W. Agricultural Gazette 77:42