Nind Deer in northern Southland did an on-farm trial to check whether the pre-winter copper injections routinely given to weaners were actually worth it. A mob of 600 was wintered on fodder beet plus baleage, with half injected and half untreated.
The copper-injected weaners grew 39g/day faster than the untreated weaners between May and September.
This yielded an average 5.6kg liveweight advantage, translating to a $34 return for a $1 investment in the copper injection.
Dave Lawrence, who presented the findings on behalf of Aaron Nind, said farmers have had a fetish for copper and wasted millions pouring it down throats. He said it was uncommon to see a growth rate response to copper treatment, so was surprised by the results. He noted the two mobs were managed the same,although run separately, which may have influenced the outcome. He also noted the injections were done two weeks after the initial weighing. “In a perfect world they would have been run in one mob."