Skin follicle types, ratios, and population densities in Rajasthan sheep breeds

Abstract

Observations are reported of skin follicle types, ratios, population densities, and percentages of medullated fibres in four Rajasthan sheep breeds – Chokla, Marware, Jaisalmere, and Malpura. Data from three body regions – shoulder, side, and breech – were available for a total of 21 sheep, and for 12 more there were observations for at least one of the three regions. The Chokla breed had the highest total and highest primary follicle population density (9.4 and 3.1 per mm2 respectively), as well as the highest ratio of secondary to primary follicles (2.1) and the lowest percentage medullation (24 per cent. of all fibres, 2 per cent. of secondary fibres). The Malpura breed had the lowest total and lowest primary follicle population density (5.6 and 2.5 per mm2), and was equal with the Marware breed for the lowest ratio (1.3). The Malpura breed had the highest percentage medullation (77 per cent. of all fibres, 60 per cent. of secondary fibres). Of the three body regions studied, the side had the highest ratio of secondary to primary follicles in all four breeds, while the breech had the highest percentage of medullated secondary fibres. The percentage of medullated primary fibres in the breech was equal to or greater than that in either of the other regions.

The Skin of the Sheep: a Comparision of Body Regions

“…Groups with no S follicles were confined to sparsely haired regions, and groups with less than five S follicles were common in haired regions but seldom seen in wool-growing regions. The P +S follicle densities in the wool-growing regions of Indian breeds (KrishnaRao, Schinckel, and Clarke 1960;Narayan 1960) were similar to the densities in some of the hair-growing regions of the domestic sheep used in the present study. The P follicle densities showed more variation in haired regions than in wool-growing regions.…”

“…Burns 1954;Hardy and Lyne 1956;Lyne 1961) and follicle populations in adult animals (e.g. Ryder 1957;KrishnaRao, Schinckel, and Clarke 1960;Narayan 1960Narayan , 1961. Studies of skin structures in addition to the follicles have also been mainly concerned with wool-growing regions (Ryder 1956;Lyne 1957;Chapman 1965).…”

The Postnatal Development of Wool Follicles, Shedding, and Skin Thickness in Inbred Merino and Southdown-Merino Crossbred Sheep

“…Although several authors (Burns 1949;Narayan 1960) have referred to occasional follicles similar to the primo-secondaries described here, no quantitative observations on these follicles are available. Both Burns and Narayan classified these follicles as primaries despite their aberrant position.…”

Maternal nutrition during pregnancy influences offspring wool production and wool follicle development1

“…Primary wool follicles appear and complete development during mid to late pregnancy, whereas secondary wool follicles appear during late gestation, with the 3819 maximum rate of maturation occurring 1 to 3 wk after birth (Short, 1955;Hardy and Lyne, 1956), Because development of wool follicles occurs during fetal life, maternal nutrition can affect wool follicles and wool production of the offspring (Narayan, 1960;Schinckel and Short, 1961;Lyne, 1964), The length of maternal nutrient restriction can either enhance (Everitt, 1967) or decrease (Kelly et al,, 1996) wool production of the offspring. Although Se supplementation to growing lambs has been shown to increase fleece weight (Cabbedy, 1971), it is unknown how Se supplementation to pregnant ewes might influence wool qualities.…”