@conference {40418,
	title = {Comparative performance of ewes shorn either once-yearly or 3 times in 2 years},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {52},
	year = {1992},
	month = {Jan},
	pages = {225-228},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The determinants of wool production per unit area of skin are  reviewed, and found to be dominated by follicle volume. Evidence is  presented to show that follicle cells destined to become fibre cells  differentiate into a continuum of cell types rather than discrete  populations of medullary, ortho- and paracortical cells as the  literature suggests. Fibres of the same dimensions grown by a sheep at  one point in time contain differing proportions of these cell types. It  is hypothesised that there is a degree of independence between fibre  volume and cell differentiation. Medulla formation is explained in  terms of competition between follicles for keratin precursors, so that  fibre volume exceeds the available volume of keratin. A similar  mechanism is proposed for the cortex, where paracortex and mesocortex  become less prevalent as total fibre volume increases. It is concluded  that a model for fibre formation can be considered in two parts: one  which generates fibre volume and another which determines cell type  within that volume.  },
	issn = {1176-5283},
	author = {Sumner RMW and Webby RW and Winter RD}
}
