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A study on productivity in sheep flocks in the south west of Western Australia : A model for the application and evaluation of health and production programmes

Bell, Kevin John (1986) A study on productivity in sheep flocks in the south west of Western Australia : A model for the application and evaluation of health and production programmes. PhD thesis, Murdoch University.

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From 1979 to 1982, a study was conducted in the Kojonup district of Western Australia on the provision of veterinary services to the sheep industry at the farm level. The objectives of the study were:
(i) To examine and evaluate management and other factors affecting sheep enterprise productivity.
(ii) To develop guidelines and methodologies for integrated health and production programmes applicable to sheep farms.
(iii) To assess the economic impact of sheep health and production programmes over a number of years by reference to control properties.
(iv) To examine in detail certain of the procedures incorporated into planned sheep health and production programmes.

In the last two decades international consensus has been reached that veterinary services to the livestock industries are best provided by planned animal health and production programmes. The nature and development of these programmes was reviewed as well as the history and principles of farm management advisory services in Australia.

As a result of this review, a model service for the sheep industry was planned. First a farm data base was created. This enabled the evaluation of the physical and financial effects of the health and production programmes and facilitated the identification of associations between inputs and outputs.

By reference to data from 36 farms over 4 years, key factors associated with sheep enterprise profitability were identified. The sheep enterprise gross margin per hectare was found to be highly correlated (p < 0.01) with gross margin per dry sheep equivalent, livestock and wool income per hectare, percent of income derived from livestock profit, lamb marking percentage, adult sheep wool per head, wool per hectare and winter stocking rate. A significant degree of correlation (p < 0.05) was obtained with time of lambing (June or earlier compared with July or later) and percentage of sheep losses (negative correlation).

Following a year of monitoring farm performance in 1979, a series of veterinary professional visits were instigated on 18 properties (the experimental group) during the period 1980 to 1982. The timing and content of these visits was based on health and production factors of economic importance identified and tailored to sheep management systems. The main professional inputs were as follows:
November to February - examination of rams for breeding soundness, review of joining programme, monitoring and planning parasite control programme, budgeting of supplementary feed requirements and bodyweighing of sheep.
March to July - sheep and pasture inspection and evaluation, bodyweight monitoring, collection of farm production data for comparative performance analysis, pregnancy diagnosis and monitoring of parasite control.
August to October - assessment of pasture quality and quantity, analysis of lambing data, review of farm performance and planning for next season.

The performance of the experimental farms over the years 1979-1982 was compared with that of a similar group of 18 control farms. The indices used in the comparison were derived from the farm data base, with the variable gross margin per hectare being used as the major indicator of sheep enterprise performance.

From 1980 there was a divergence between the groups in favour of the experimental group, reaching significance (p < 0.05) in 1981.

During the three years measured, the programmes yielded a mean benefit-cost ratio of 714 per cent, and when the difference between the groups was standardised for farm area, a mean benefit per farm attributable to the programmes was $3992.00. The mean increase in profitability over the three years measured was 8.6 per cent per farm.

Considered areas of loss common to many farms at the commencement of the programmes were: below optimum soil fertility and stocking rate; inappropriate time of lambing; inaccurate selection of sheep for slaughter; lack of objectivity in selection of breeding stock; and
inappropriate supplementary feeding. Consequently these were major areas of input in the programmes applied.

Consequent upon the needs of the sheep enterprises involved, two specific technologies were developed as part of the project. A facility was designed to enable field application of ultrasound pregnancy testing, using the "Scanopreg" machine, and this technique compared with the use of harnessed rams to detect non-pregnant ewes. For 2691 ewes in 8 flocks, the harnessed rams detected on average 55.8 per cent of the ewes diagnosed as non-pregnant by the ultrasound technique. Other advantages of the ultrasound technique are discussed, and the economics of pregnancy testing by this method were evaluated.

In the area of supplementary feeding, non-protein nitrogen was utilised to improve the value of oats as a supplement to sheep grazing wheat stubble and as an additive to oat straw in a total maintenance ration for sheep.

Sheep grazing wheat stubble and receiving 200 grams per head per day of oat grain treated with 2 per cent urea, maintained bodyweight over a 6 week period compared with a weight loss of 2.9 kg in sheep receiving the same quantity of untreated oat grain. This difference was significant (p < 0. 05). When oat straw was fed ad lib. To weaner sheep in combination with 100 grams per head per day of oats, straw treatment with 2 per cent urea significantly reduced weight loss over 2 months from 2.9 kg to 0.4 kg (p< 0.01).

The documented results and subsequent farmer acceptance of this model health and production programme indicate that a practical means of productivity improvement within the Australian sheep industry has been developed.

Item Type: Thesis (PhD)
Murdoch Affiliation(s): School of Veterinary Studies
Supervisor(s): Swan, Ralph, Nairn, Malcolm and Chapman, Helen
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