Cattle at risk of trace element imbalance when switching to winter forage diets

Beef and dairy farmers are being alerted to the risk of trace element and vitamin imbalances as cattle switch from grazed grass to forage-based rations.

If not addressed, this could have a major impact on productivity, with micronutrients playing a critical role in health, performance, and fertility, explains Tom Butler, technical manager at B2B Nutrition, the trade arm of the Brinicombe group.

“Housing can be a particularly stressful time for cattle and sudden changes in environment, animal groups, and diet, are all factors which can impact trace element and vitamin status”, he says.

Forage always has the biggest impact on micronutrient balance from the base diet as it’s generally the largest component of the ration.

With this in mind, Mr Butler says it is important to be aware that not only does fresh grass vary in trace element and mineral content, but also that silage does not provide equivalent levels to fresh grass.

“This is down to the pH change during the ensiling process, which denatures vitamins and causes the leaching of minerals. Other feeds that are also used in winter rations, for example cereals, are also often lower in micronutrients,” he adds.

On top of potentially lower dietary supply, the additional stress at housing can increase the requirements for trace elements and vitamins.

“Copper is often the most discussed trace element that is lacking, but zinc, iodine and selenium are just as important to help combat potential stresses at this time,” explains Mr Butler.

“The need for vitamins A and E should also be considered for a range of health functions alongside vitamin D3, as the reduction in sunlight means that animals won’t be able to synthesise the quantity they do when outside in the lighter months,” explains Mr Butler.

Determining whether cattle are suffering from a trace element deficiency can be difficult as micronutrition covers so many intricate functions, meaning that signs of deficiencies manifest in different ways.

“Some signs may be present such as dull coats, coarse hair and general poor performance, but analysing forage to check micronutrients levels is one way to determine whether there is need for supplementation,” advises Mr Butler.

When it comes to balancing deficiencies in cattle at housing, he says there are two approaches. Farmers can take either a precision approach – which can prove beneficial in situations where there are large enough group numbers to make bespoke supplementation viable – or a broader approach, for example via bolus technology.

“Bolusing is a practical and convenient option that suits many farmers at housing and allows for a ‘little but often’ approach, topping the animal up every day with micronutrients.”

When selecting a bolus, Mr Butler says consideration should be given to the consistency of nutrient release and length that the bolus will last. A dual trace element and vitamin bolus may also prove beneficial, as vitamins are key for health and production at this time.

“Don’t always assume the status quo. Think about issues in previous years and discuss potential indicators, such as health or performance problems that have previously been seen, when considering nutrition at housing. These indicators can direct the requirements for supplementation that aren’t always picked up in analysis,” he concludes