Dry and early lactation cows fed maize and wholecrop-based diets could benefit from greater supplementation with the antioxidants vitamin E and beta carotene, according to new UK farm survey results, which identified widespread deficiency.

The survey involved 10 farms in the South West of England and was undertaken by Molecare Farm Vets, in partnership with DSM. The results showed that:

l 90% of fresh cows were deficient in vitamin E and 75% deficient in beta carotene.

l Half of dry cows were deficient in both antioxidants.

l 30% of cows were still deficient in both antioxidants, three weeks after calving,

The data is in-line with existing research findings which highlights an increased risk of vitamin E and beta carotene deficiency in house systems feeding ‘yellow’ diets made up of more than 50% maize, straw and wholecrop. Compared to ‘green,’ grass-based diets, these forages tend to be low in key antioxidants. This was underlined by the fact the only farm feeding a ‘green,’ grass silage based ration, was not deficient in beta carotene at any point.

The fact all of the farms feeding ‘yellow’ diets were already supplementing with vitamin E, suggests inclusion rates need to be raised on these feeding systems. Although beta carotene is not typically supplemented in the UK, the data also suggests it could be worth providing cows with this antioxidant when grass inclusion rates are reduced.

Vet Andy Adler of Molecare Farm Vets, says the correct supply of vitamin E and beta carotene is vital considering the role they play in fertility. “Antioxidants are involved in protecting the body’s cells from detrimental chemicals that are produced in response to normal insult and trauma seen around calving,” he explains. “If these chemicals aren’t removed, they can have a negative impact on bodily tissues, and particularly those involved in fertility, such as the growing oocyte (egg).”

Providing cows with antioxidants helps counteract these detrimental chemicals and protects the growing oocyte. With the oocyte starting to develop 100 days before a cow comes into heat, making sure she has sufficient levels during the dry and transition period is essential.

Jamie Gibbons, Mineral Supplements Technical Manager for Mole Valley Farmers, says this is underlined by the fact a high proportion of freshly calved cows were found to be deficient.

“This shows it’s worth increasing supplementation around calving to raise blood levels and help prepare the cow for increased demand when she calves,” he says. “Supplementation with key antioxidants - including vitamin E & Beta carotene - during the dry period and up until cows are served will give the best protection for the developing oocyte so it is ready for fertilisation.”