Published online by Cambridge University Press: 27 March 2009
Wool-growth rates were measured at monthly intervals on eight free-grazing Cheviot wethers. Nutrient intakes provided by the upland environment were measured at the same intervals during the 2½ years. Analysis of periodic regression disclosed that both intake and wool growth had similar seasonal cycles but were slightly out of phase. It was concluded that the similarity was largely due to the relationship of both characters with some independent seasonal variable. The seasonal cycle of efficiency of wool growth depends on the time relationship between its two components, but it was found that variation amongst sheep in wool production was greater in the summer months and this depended more on variation in overall efficiency than on variation in grazing intake.