Copper deficiency: A review of the economic cost and current constraints to effective management of copper deficiency in southern Australian sheep flocks

Summary

As pasture testing has continued to reveal a broader issue of copper deficiency in areas not previously considered at risk, this trial was initiated to investigate the prevalence, effects, identification and treatment options for copper deficiency in sheep flocks. Following an extensive literature review, a series of trials were conducted at six sites in South Australia and Victoria to measure the impact and effect of treatments on copper deficiency.

It was found that scouring and lameness in sheep are not directly related to copper deficiency, as is commonly believed. The greatest production effect of copper deficiency was a reduction in ewe and lamb survival rates. A range of methods were tested for identifying the extent of copper deficiency on a property, with pasture mineral analysis proving to be the most useful and cost effective option for producers to implement.

A range of treatment options were trialled; each was effective at elevating liver copper concentration in line with their respective copper dose rate. Selection of the most appropriate treatment will depend on the severity of the deficiency and the required treatment length of time. Professional advice should be sought in recommending an appropriate copper dose rate as toxicity can be experienced where excessive amounts of copper are provided.

Objectives

This project aimed to:
•Review the literature and consult with industry to determine the efficacy of current treatments across different environments, the reasons for the apparent variable response to current treatments, the relationship of copper deficiency with scouring, lameness, lamb mortality, infertility and its effect on wool quality and to identify the extent of the problem over southern Australian sheep production systems
•Undertake soil, plant and animal measurements to determine the correlation between each, the potential to use soil and/or plant analyses as an indicator for potential copper deficiency in sheep, if the time of year or stage of plant growth influences the copper status of plants and to validate the accuracy of blood and liver copper analyses
•Determine the treatment options most likely to be effective in treating copper deficiency at each trial property and implement an efficacy trial

Key findings

This project found that neither soil tests or blood tests are an accurate measure of pasture or animal copper status. Instead, pasture tissue analysis can provide an accurate indication of animal copper status where repeat measurements are taken over a period of time.

It was also found that each treatment tested was effective at increasing liver copper concentration, with ruminal boluses and capsules having the greatest effect.

Copper deficiency was not shown to be directly related to lameness or scouring in this study. When severe copper deficiency exists, supplementation can significantly improve ewe and lamb survival rates.

Benefits to industry

More effective treatment of copper deficiency will improve animal productivity and welfare, and increase survival rates.

MLA action

The results of this project provide producers with a variety of key actions they can implement on farm to ensure that copper deficiency does not affect the productivity of their sheep flock.

Future research

The literature review found that further research is needed into the prevalence of copper deficiency across southern Australia, the area of copper nutrition for soils, the effects of soil ingestion at different intake levels, the effect of interacting minerals, copper related infertility and the optimal supplementation management for reproductive benefits.