Zinc deficiency in cattle causes parakeratosis, reduced immune function, reproductive failure, and growth retardation, with welfare implications that are often subclinical and underdiagnosed.
Zinc deficiency causes welfare harm across a spectrum from subclinical immune compromise to clinical skin disease. At the subclinical level, impaired immune function results in higher rates of infectious disease — respiratory illness, mastitis, and foot disease occur more frequently and severely in zinc-deficient cattle. Skin parakeratosis causes visible discomfort and secondary bacterial infection of thickened, fissured skin. Impaired hoof horn production from zinc deficiency contributes to lameness susceptibility — hoof horn quality depends on adequate zinc for normal keratinization. The welfare impact of subclinical deficiency is difficult to attribute definitively to zinc but contributes to the aggregate disease burden of affected herds. Straightforward supplementation programs prevent these welfare costs entirely in deficient populations.