Zinc wins approval

SUPPLEMENTING EWES with zinc can increase the performance of lambs, according to a trial at Harper Adams University College, Shropshire.

Ewes were initially fed 0.8kg concentrate/day in two feeds, increasing by 0.1kg/week to 1.3kg/day at lambing. This rate continued throughout lactation, explained Sandy Mackenzie, who ran the trial for feed supplement supplier Alltech.

“Two diets were supplemented with an additional 50mg zinc/kg either as zinc oxide or zinc proteinate BioZn. Levels of zinc equalled 288mg/kg DM in the zinc oxide and 260mg/kg DM in the BioZn concentrate.”

Of the 40 Suffolk-cross ewes, those supplemented with zinc proteinate had higher lactose concentrations in milk, compared with ewes supplemented with zinc oxide.

Although there was no significant effect of zinc source on lamb weight, lambs from the ewe supplemented with BioZn tended to be heavier at four weeks of age. “Lambs from BioZn ewes also had higher daily liveweight gain compared with lambs from zinc oxide ewes,” Dr Mackenzie added.