You’ve probably heard vets or fellow farmers discussing trace elements before, but do you know what they actually are and more importantly do you know the status of your herd (or flock). Trace elements are minerals that are essential for normal health and function of animals in small quantities. The trace elements of note in the UK include cobalt, copper, selenium, and iodine.
Traditionally trace elements have been easily overlooked as lots of the signs of mild deficiency are subclinical or low-level ill thrift, but they perform a variety of vital roles including in energy metabolism and immune response. But getting the balance of these minerals is important as if animals are deficient this can result in ill-thrift, or reproductive failure, but if they are provided in excess can cause poisoning.
Trace element availability in both grass and forage is altered by lots of factors including soil type, pH, geology, drainage, plant type and weather, and therefore varies from farm to farm and within different cuts of silage. Youngstock, pregnant cattle and lactating cattle are at most risk of mineral deficiencies and these are particular groups to think about a trace element strategy for.
If you suspect your cows may be deficient in any of the trace elements it is always worth identifying the specific problem rather than jumping to supplementation. Unnecessary supplementation is at best a needless expenditure and at worst can lead to an excess of minerals resulting in poisoning. In fact, copper poisoning due to unnecessary excess supplementation is increasingly reported and copper deficiency is becoming less common. It is also important to rule out lack of energy in the diet or parasitic disease, which are both more common causes of ill thrift, before assuming trace element deficiencies are the problem.
The most common way of identifying a problem tends to be via blood sampling 6-10 cows when they have been on a consistent diet for a period of time. Individual samples are usually taken to assess selenium and copper status whereas samples are usually pooled to assess Iodine. It is worth noting there is no reliable blood test for cobalt in cattle. Other ways to assess trace element status include liver biopsies or sampling livers from the abattoir for copper and cobalt. Iodine status can also be assessed on post-mortem of weak/still born calves. It is also worth finding out what your local soil and pasture type are and considering samples from soil or forage.
Traditionally supplementation on many farms has been lick buckets or additives to water and whilst these are better than nothing, there is no way to guarantee individual uptake and allow animals to be under or occasionally over supplemented. Conversely long acting, slow releasing boluses provide a consistent supplementation across the herd and over a long period of time. This is particularly useful in beef herds where the mainstay of the diet is grass which may be variable in trace element profile.
There are lots of different supplementation options out there and if you’d like to discuss it more or take the first step and find out what the trace element profile of your cattle is do give your vet a call. Each farm will be different in what is useful and what is practical, and we’d love to work with you to help minimise subclinical disease.
Trace elements in cattle – what you need to know: