Copper is essential for optimal pasture growth, as well as animal health, and is unique for its interactions with other essential element.
Excesses of both molybdenum and sulphur can induce copper deficiency in animals receiving an otherwise adequate dietary copper concentration.
Copper deficiency is most remembered for its association with “steely” wool in sheep – the wool harsh-handling, unevenly crimped and is weaker than normal.
Deficiency may cause a variety of other symptoms in sheep and cattle – anemia, illthrift, scouring, bone abnormalities, and reproductive disorders – some of which have been detected in goats receiving inadequate dietary copper.
Copper toxicity is also a significant animal health problem, particularly in sheep. Toxicity can be induced in 3 ways:
• Overdosing with copper supplements.
• Prolonged grazing on clover-dominant pastures.
• Prolonged grazing on heliotrope (contains a liver toxic alkaloid).
Extreme caution should be used with copper supplementation, and any producer who suspects that stock are suffering from copper deficiency should seek specialist advice from a veterinary practitioner or the Department of Agriculture.
Copper is more available to livestock from dry pastures and hay. Hence, copper deficiency in Victorian livestock has a definite seasonal cycle. Problems are worse in the winter-spring period and are often resolved over summer-autumn even with no supplementary copper.
Historically, copper deficiency has often occurred in conjunction with cobalt deficiency. – “Coast Disease” – and many affected areas have received copper fertilizer applications. In contrast to cobalt however, copper fertilizers appear to provide adequate pasture copper for many years (at least 15 years according to one source) and problems of copper deficiency in livestock in more recent times are usually introduced or secondary to excessive intakes of molybdenum, sulphur and possibly other elements such as iron.
Molybdenum toxicity (molybdenosis, molybdenum-induced copper deficiency) may be due to naturally occurring molybdenum pastures (e.g. peat swamps), can be a result of application of molybdenum fertilizers to pasture and has been associated with the application of lime fertilizers to pasture to treat soil pH.
In districts that have shown any signs of copper deficiency in goats, cattle or sheep, advice should be sought from the Department of Agriculture on need for copper fertilizer or copper treatment of livestock, especially if contemplating the use molybdenum to boost pasture production.
Topdressing: The most practicable means of control of copper deficiency in goats is by topdressing pastures with fertilizers that are fortified with copper oxide. Copper is normally applied at from 0.5 to 2 Kg per hectare every one to seven years respectively on part or all of the farm.
Injections: An organic copper injection (Cujec) which lasts for some months is available for sheep, but its safety in goats is uncertain.
Problems associated with injectible copper compounds have included abscesses at the site of injection due to poor technique, and toxicity.
Injectible copper therapy is suitable for both primary and conditioned (i.e. molybdenum induced) forms of copper deficiency, and a single treatment provides adequate copper for 2-3 months.
Drenching: Oral drenching with an aqueous solution containing copper sulphate is useful in primary copper deficiency only. Copper sulphate may be mixed with levamisole-based and oxfendbendazole anthelmintic drenches, and should be used within 24 hours. Copper is not compatible with many other drenches. With primary copper deficiency, a single oral treatment is adequate for 1-4 weeks. However for copper deficiency due to excess molybdenum, weekly treatments may be required, making form of treatment generally impractical. Copper-containing salt licks may be used where individual animal treatment is impractical.
Treatment over the period from mid-winter to spring is usually sufficient for all but the most severely deficient animals. Treatment should be aimed at providing adequate copper nutrition for at least six weeks prior to kidding. New treatments such as copper oxide needles and glass bullets have been developed and are being tested prior to commercial release.