Zinc status of cows as deduced from the liver zinc content.

Abstract

The zinc content of cow's liver was estimated in livers collected from slaughterhouses in The Netherlands. A total of 333 samples taken in autumn and early winter had an average Zn content 125+or-29 mg/kg DM, with 32 outliers (Zn 212 mg/kg and higher). The distribution of the high outliers, along a line extending from NW to SE over the country, may be related to geophysical factors, but also to feeding practice. Some very low Zn contents could be found by subtraction of the residual active Zn that is part of enzymes, about 90 mg/kg, and logarithmic transformation. Thus 29 low outliers could be traced, all with effective Zn storage below 10 mg/kg. Hence in the total material, nearly 10% was gravely deficient, some 40% suboptimal, and 10% excessively rich in Zn. Liver Zn seems a good means of assessment of the liver status of cows, on a much shorter time basis than for typical storage elements like copper. As a means of investigating interactions, the method was less satisfactory, at least for Zn relative to copper and iron. (Abstract retrieved from CAB Abstracts by CABI’s permission)