Which key antioxidants are linked to fertility?
Dry and early lactation cows fed maize and wholecrop-based diets could benefit from higher levels of 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 Vets, in partnership with DSM.
The results showed that:
• 90% of fresh cows were deficient in vitamin E and 75% deficient in beta carotene
• Half of dry cows were deficient in both antioxidants
• 30% of cows were still deficient in both antioxidants, three weeks after calving.
The data highlights the increased risk of vitamin E and beta carotene deficiency in housed 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, did not have issues with deficiency.
All of the farms that were feeding ‘yellow’ diets were already supplementing with vitamin E, but were still deficient, which suggests inclusion rates need to be raised in 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 it’s vital cows fed ‘yellow’ diets are supplied with sufficient levels of vitamin E and beta carotene, particularly considering the crucial 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 and 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. “The National Research Council (NRC) is currently reviewing recommendations for antioxidants and is likely to increase recommended levels in dairy diets. Our survey suggests this is the right move. Fertility is multi-factorial, but optimal antioxidant status is one thing that contributes to better conception rates and more cows in-calf.”
•150 cows on 10 dairy farms in the South West
•One grass silage-only system.
•On the remaining farms, cows were housed and fed maize, wholecrop and grass silage
•Blood tests carried out between November 2019-January 2020, using the i-Check device
Test groups (five cows in each group):
• -28 to -7 pre-partum = Dry cows
• 0-14 days in milk (DIM) = Freshly calved cows
• 15-45 DIM = Early lactation cows
Blood antioxidant deficiency on i-Check device defined as:
• <3.5mg/ml of beta carotene
• <3mg/ml of vitamin E
Current antioxidant supply guidelines:
• Up to 1,000mg per cow per day of beta carotene pre-calving through early lactation
• Up to 4,000 IU per cow per day of vitamin E for close-up dry cows
(Professors Bill Weiss, Ohio State University; Jo Leroy, University of Antwerp; and Sergio Calsamiglia, Universitat Autonoma de Barcelona).
New Antioxidant Packs Launched to Support Fertility
Mole Valley Farmers has launched two fertility mineral packs that include the right level of antioxidants to meet the cow’s needs in the dry period and early lactation.
The “Green” Fertility Pack is ideally suited to systems that feed a predominately grass silage-based diet, whilst the “Yellow” Fertility Pack has increased levels of these key antioxidants to reflect the lower natural levels in maize and wholecrop-based diets.
This will form part of a “Fertility Link 365” programme from Mole Valley Farmers, aimed at providing farmers with support to improve fertility performance on farms.