Biofortified fodder - an environmentally sustainable mechanism to supplement livestock with trace elements?

Abstract

New Zealand agriculture utilises trace element supplements to protect livestock from fungal infection. For example Zinc (as zinc oxide) administered as an oral drench or intraruminal bolus, is used extensively to protect sheep and cattle from facial eczema. A large percentage of administered Zn is however excreted in faeces and there is published evidence to show that Zn levels in pastoral soils are increasing with time. The long-term environmental affect of this ongoing Zn input to soil is unknown. In this paper we describe research into the efficacy of fodder with an elevated Zn concentration as a potential prophylaxis against facial eczema in sheep relative to a conventional drench. Our hypothesis is that Zn protection afforded by biofortified fodder may be realised at a relatively lower dose, thus limiting transfer of Zn into the pastoral environment. This may represent a more environmental sustainable mechanism to supplement livestock with trace elements than conventional options. Our mechanism of Zn administration can be described as the biofortification of food with essential trace elements.