Abstract

Wiltshire Horn sheep exhibit an annual moult in spring and potentially provide a model for studies on the seasonality of wool growth. Twelve, 1 year old New Zealand Wiltshire ewes (Wiltshire Horn with some Poll Doreset in ancestry) were kept indoors under natural light and fed concentrates and hay. The sheep were cored for extent of fleece shedding every 2 weeks and skin sampled monthly for histological determination of primary and secondary follicle activity. Follicle activity reached a peak in summer and autumn (January to April) with low activity over winter (May to August) resulting in partial or entire shedding of the fleece in spring and early summer (September to December). There was evidence of a subsidiary shedding cycle in the primary follicles in early summer. Seasonal follicle activity was higher and longer in duration than previously recorded in British Wiltshire Horn ewes maintained on pasture. Four sheep with highly seasonal follicle activity cycles were identified as suitable for further studies on the endocrine control of wool growth. Such sheep can be selected from skin samples collected in June, July and August when follicle activity is at a seasonal minimum.

JJ, Nicol

Proceedings of the New Zealand Society of Animal Production, Volume 51, , 319-322, 1991