Effect of adverse nutrition on the skin and wool follicles in Merino sheep

Abstract

The effect of adverse nutrition on the body weight, skin thickness, and wool follicles of five groups of five Merino wethers has been observed over a period of 64 months in an experiment on the utilization of low quality roughage.

All animals on the poorest diet (roughage containing 2.6% crude protein, ad lib.) were transferred to a recovery ration of lucerne chaff, wheat, linseed meal, and meat meal (33 : 33 : 20 : 13) at 6–9 weeks after the commencement of the experiment. Only three animals on the better diets needed this recovery ration.

In general, changes in skin thickness paralleled changes in body weight. A marked increase in skin thickness which followed shearing was probably due to cold stress.

Fibre shedding was a major feature of the reaction of the follicle population to adverse nutrition, but all afflicted follicles regenerated their fibres when the recovery ration was given. Primary (P) and secondary (S) follicles responded differently to adverse nutrition. Approximately 20 000 P follicles and 155 000 S follicles were examined. 1.4% of the P follicles and 9.%% of the S follicles showed evidence of shedding.