Influence of endogenous factors on the ash, calcium, magnesium, potassium, sodium, phosphorus, zinc, iron, copper and manganese contents in the bristles of pigs. 3. Influence of time of cutting on the mineral composition of the hair (boar bristles)]

The ash content and the content of Ca, Mg, K, and Na in the bristles of pigs is influenced by the age of the animal and by the season of the year. The peak concentrations of ash, Ca and Mg in the bristles of eight boars (cut every month) were found in June, shortly before the change in hair coat. (P less than 0.05-0.001). The concentrations of K and Na in the bristles deviated functionally from the change in the hair coat. In the first half of the year the bristles of the boars contained significantly more K and Na than in the second half. Values for the elements P, Zn, Fe, Cu, and Mn were subject to great variations through the year. These variations were found to be different with different animals. The influence of endogenic factors on the Mn content of the bristles was particularly striking, also in regard of the order of magnitude. The processes of Mn metabolism in the bristles are obviously still archaic in origin and would thus only allow to make comparison with other values of the mineral content of bristles at the very time of sampling. Differences in the P, Zn, Fe and Cu content of bristles in the different months were, in some instances, statistically significant although variations in the annual mean values were found to be relatively small.