Observations of nutritional and seasonal changes in the fleeces of some masham sheep

Abstract

1. An experiment was carried out in summer when sheep do not normally shed their wool fibres to see if a poor diet would induce fibre shedding. Observations were then continued for a year to follow seasonal variations in the fleece. 2. The two experimental sheep lost about a quarter of their body weight during the nutrition experiment. Measurement of areas tattooed in the skin showed that there was a reduction of about 5% in these areas. 3. Histologieal observations of skin samples showed that there was very little fibre shedding during the nutrition experiment. This suggests that poor nutrition alone will not cause sheep to shed their fibres. More fibre shedding took place during the winter even though the sheep were well fed, suggesting a seasonal stimulus for shedding. 4. ‘Brushes’ which are normally formed when fibres shed in primary follicles were also seen in secondary follicles. 5. Observations were made during the nutrition experiment of the blood vessels in the skin and glycogen in the outer root sheaths of the follicles. No changes were seen in either the numbers of vessels, or the amount of glycogen present. 6. The weight of wool produced per unit area per day was determined at each sampling time during the whole year. The experimental sheep behaved differently from the controls in their wool production during the nutrition experiment. Thereafter all sheep behaved the same, and seasonal fluctuations in wool production were found. 7. The mean length and mean diameter of the wool produced was determined at each sampling time throughout the year.