Copper deficiency is a recognised side effect of feeding zinc to livestock. However, not all animals are equally susceptable, and because copper supplements are potentially toxic themselves, treatment for copper deficiency should never be random (as in treating an entire herd as a preventive measure), but should be restricted only to those animals that have had a blood test that shows they are copper deficient.
Supplementation for alpacas is further complicated by the fact that copper supplements are based on dosage for cattle, making estimation of dosage for alpacas difficult or impossible. In cattle, the two ways of treating coppler deficiency is the use of “copper bullets” or by injection. Copper bullets are large round balls made up of tiny filiments of copper wire. Drenching is by means of a copper bullet “gun” which shoots the bullet down the throat to break down in the stomach. Alpacas have a different digestive system to cattle and the effect of this on copper bullets is unknown, but in any case, the smallest copper bullet is still too high a dose for alpacas, and you run the risk of killing your alpaca rather than curing it.
Injections are not much better. They are fatal to unborn cria, and calculating the dose incorrectly can also kill an adult alpaca. The injections are extremely painful and lead to massive scarring at the injection site.
Case study: Sinti
Sinti was raising a large cria and started to show a concerning amount of weight loss. Thinking the cria may have been draining her reserves, we weaned him early (at 5 months of age), however Sinti continued to show weight loss and also developed diarrhoea. We treated her for worms, and with AD&E/phosphate doses, as both these common conditions can cause these symptoms. However, there was no improvement, so we had a blood test taken which showed her to be copper deficient.
Our vet was unable to recommend suitable supplementation. We also consulted an alpaca specialist vet who also could not recommend a suitable treatment. Sinti was already pregnant. The copper bullet was too dangerous to give Sinti. The injection might save Sinti, but would kill her unborn cria. Even halving the normal dose could still prove fatal for Sinti. Not treating the copper deficiency was likely to prove fatal. It was a case of damned if you do, and damned if you don’t.
Our choice was to use neither forms of supplementation until the cria was born, and then to use the injection. Unfortunately, Sinti’s full-term cria was still-born. Sinti’s condition was unchanged. We decided to give Sinti a vitamin supplementation designed for horses(Tracemol) that included small amounts of copper – not enough to be toxic. This is an oral drench, and we gave Sinti a 5ml dose every time she came into the yards. Over a period of time, she started to put weight on, the diarrhoea cleared up, and 6 months later a 2nd blood test showed Sinti had normal copper levels.
We have since done further research on adding copper to pasture. There are a number of agricultural sprays which can be sprayed onto pasture. The copper is absorbed by foliage and becomes available to grazing animals in non-toxic quantities. However, the benefits are not long lasting. There is a withholding period of around 1 week after spraying when animals cannot graze sprayed pasture. By 2 weeks after spraying the copper is no longer available to grazing animals, so you have only about one week to run your alpaca on the supplemented pasture. However, we have done this, and intend to do it again, as that one week appear to be highly beneficial.