New Zealand Journal of Agricultural Research abstracts

---

Relationships between cell proliferation in the follicle bulb and dermal papilla measurements in wool follicles from New Zealand Romney sheep during different seasons

S. A. HOLLE^1,*
P. M. HARRIS²
A. S. DAVIES³
A. J. HALL⁴

1Department of Veterinary Clinical Sciences
Massey University
Palmerston North, New Zealand
2AgResearch
Grasslands Research Centre
Private Bag 11008
Palmerston North, New Zealand
3Department of Physiology & Anatomy
Massey University
Palmerston North, New Zealand
4Horticulture and Food Research Institute
Private Bag 11030
Palmerston North, New Zealand

Abstract  Little information is available on the influence on overall fibre production of either size changes in the follicle bulb or relative changes in bulb structures. Various criteria have been used to quantify the size of the germinative tissue zone but none have been assessed for their suitability or sensitivity as predictors of bulb cell production and cortical cell migration. This study investigated the relationships firstly between the number of replicating cells in the follicle bulb and various measurements of follicle bulb diameter and areas, and secondly between 3-dimensional extrapolations of bulb measurements and papilla dimensions. The raw follicle data are derived from a companion study (Holle et al. 1994) of Romney sheep with two genetically different levels of wool production examined during periods of low (winter) and high (summer) fibre production. Strong relationships existed between similar measurements (e.g., diameters), but their relationship varied with season. Bulb diameter was only weakly related to bulb area and bulb volume, but papilla length was most closely associated with bulb volume regardless of season or genotype. Correlations between fibre diameter and inner root sheath (IRS) diameter changed significantly with season and no relationship existed between IRS diameter and bulb volume during summer. This suggests that the distribution of cells between the IRS and fibre varies with season.

Keywords  wool; follicle; Romney; season; sheep

New Zealand Journal of Agricultural Research, 1995, Vol. 38: 169-176

0028-8233/95/3802-0169 $2.50/0 (c) The Royal Society of New Zealand 1995

PDF file of entire paper: medium quality (551K); (scanned from paper original: notes about this process)

---

This year's abstracts | Journal home page | All abstracts | Publishing home page