An assessment of the trace element status of grazing livestock in the Wendon Valley

Abstract

The Co (Vitamin B12), Se, Cu and I status of livestock on 12 Wendon Valley farms was determined from the trace element concentrations of pasture, blood and liver samples collected in spring and autumn and comparing them to accepted trace element reference ranges established from earlier New Zealand-wide trace element supplementation trials recording animal responses. Both marginal Co and Se deficiencies in lambs were found on two farms while another three farms were marginally Co deficient, one farm was very Co deficient and a further two farms were marginally Se deficient. Iodine deficiency was observed in new-born lambs from ewes wintered on swedes, whereas the Cu status of all sheep was adequate. No Co deficiency was found in cattle but Se deficiency was observed on four farms. A marked depletion of liver Cu stores and Cu deficiency was found in all cattle and deer during the late winter/ early spring. Growth responses to Vitamin B12 and Se supplementation in lambs, and the absence of goitre in new-born lambs to I supplementation in ewes were also observed. The established diagnostic protocols based on pasture, blood and liver samples were shown to be effective in determining the trace element status of grazing livestock in the Wendon Valley. Keywords: blood, cattle, copper, deer, iodine, liver, pasture, selenium, sheep, vitamin B12