Producers should consider worming calves five weeks pre-housing this year, according to SAC beef specialist Basil Lowman. Pioneered by suckler beef producers in Scotland, dosing both suckled calves and dairy youngstock five weeks pre-housing is being hailed as a major development in worming strategy.

“It is essential calves are 100% fit at weaning,” says Dr Lowman. “By dosing animals with the long acting treatment Dectomax, which is the only wormer to contain doramectin, lungworms are killed and coughed up before housing, lessening the risk of pneumonia at weaning.

“Pneumonia is the biggest single cause of loss in the suckled calved industry, as well as being a major welfare issue. For every fatality from pneumonia, it is expected that 10 cases are subclinical, costing producers at least £40 a head in lost efficiency.”

And it isn’t just lung worm which hinders performance, with stomach worm causing a double hit – reducing both dry matter intake and absorption of energy from food eaten due to damaged gut lining, he explains.

“To maintain its intake, calves have to increase their dry matter by as much as a third,” he adds.

Research suggests gut recovery takes at least two weeks, suggesting that by worming five weeks earlier, calves’ digestion tracts will be functioning at maximum efficiency, resulting in reduced nutritional stress at weaning.

Furthermore, worming treatment could pay for itself when producers implement the five-week policy, according to Pfizer’s senior vet, Carolyn Hogan. “By getting calves worm-free five weeks pre-housing, growth rates could be boosted by 0.15kg a day, leading to an additional 5.25kg of bodyweight at weaning.”

At £1/kg, the £5.25-worth of extra weight could pay for not only the pre-housing drench, but also the use of wormer at turnout and eight weeks later. “Because producers use a wormer at housing anyway, this strategy does not require any additional treatment, just a change in timing, particularly as lice protection is also guaranteed.

“And earlier dosing means the quantity of wormer required is reduced, with calves potentially gaining 40kg in this five week period,” she adds.

Vaccination for pneumonia can be carried out during handling necessary for early worming, meaning that, along with the second dose of vaccine two weeks before housing, all stresses of administering treatments are over pre-weaning, while calves are still on their mothers.

However, farmers are advised that this strategy requires a sufficient duration of action from the wormer used. The persistent effect of the active ingredient doramectin means only products containing this ingredient can be given up to five weeks pre-housing and comes with a lice free guarantee over winter. Therefore, this strategy should not be adopted with any other wormer for internal and external parasite control at housing.


Preventing pneumonia
  • Treat pre-housing with long-acting wormer
  • Pneumonia vaccination
  • Clip backs
  • Well drained, well ventilated, housing