Supplementing maiden heifers with specific minerals has led to a 65 per cent reduction in digital dermatitis according to latest international research findings, says Advanced Nutrition’s veterinary nutritionist, Dr Debby Brown
Digital dermatitis incidence continues to run high; with at least 70 per cent of all herds infected while 40 per cent of cows in those herds suffer from the infection despite farmers introducing strategies featuring persistent foot bathing, trimming, early treatment and record keeping.
Now the focus is turning to pre-calved heifers. They experience many periods of metabolic and social challenge through their growing life which has a significant impact on their susceptibility to infectious lesions, such as digital dermatitis. In fact incidences have been found in cattle as young as eight to 10 months old and mature cattle may have first been infected during the rearing phase.
Dr Debby Brown says introducing a new prevention plan which focuses on heifer replacements would appear to offer a solution towards arresting the condition, according to the latest US trial results and field observations.
She says: “A package of specifically formulated trace minerals fed to maiden heifers to improve skin health and subsequently provide better protection has reduced the incidence of digital dermatitis by at least 65 per cent after these heifers entered the herd. The results were dependent on those specific minerals being fed prior to the heifers suffering any infectious lesion.”
The initial independent trials carried out at the University of Wisconsin featured 30 10-month-old animals suffering from digital dermatitis in the early stages. Half acted as a control group with standard treatment while the others were treated with the formulated trace mineral package Availa Plus. The trial was carried out over a 62-day period.
The control animals in this study progressed to acute stage digital dermatitis lesions approximately 10-14 days faster than those treated with the formulated trace mineral package. The treated animals also had smaller lesions which were less active than the control animals and thereby incidence was significantly reduced.
Field evaluations followed with a commercial dairy unit in Wisconsin. Maiden heifers were split into two groups, a control with standard treatment and a group fed the same formulated trace minerals from breeding until confirmed pregnant 49 days later. The treated group demonstrated a 50 per cent reduction in digital dermatitis lesions compared with the control heifers.
Added together, the official trial and field evaluations resulted in an average 65 per cent reduction in digital dermatitis lesions.
Field evaluations were then extended to 16 US farms where the same formulated trace minerals were fed for 150 days. From this, 87 per cent of farms noted a reduction in digital dermatitis, varying from 30-85 per cent. The same field evaluations have now been replicated on five European dairy units, resulting in similar trends.
Three key factors cause the spread and increased incidence of digital dermatitis: a moist environment, skin damage and the prevalence of bacteria known as treponema. Treponemes can be found on healthy skin, but they need damaged skin and moisture to invade.
Skin is made up of many cells in its different layers – the epidermis, dermis and subcutis, all contain cells that produce keratin, immune cells, pigment cells, receptor cells and basal cells within which there are 600 enzymes that work to help maintain its health, productivity and a local active immune system. Many of these enzymes need zinc to work effectively.
When treponemes enter the skin, they migrate down the intercellular spaces into deeper layers when skin integrity is weak. The US trials found optimising the link strength between cells helped skin health; with zinc and the balance of trace minerals the major contributors.
Dr Brown says: “Stress has a part to play. Increased cortisol, which is released during periods of stress, reduces trace mineral retention. Recovery after acute stress has been found to be quicker with certain mineral supplementation.
“Introducing maiden heifers to the correctly formulated mineral supplementation should become part of a dairy farmer’s digital dermatitis prevention strategy if UK herds are to reduce the incidence and prevalence of this costly, painful disease.”