Influence of hydrothermal factors on wool development of Tan sheep in China

Abstract

Hydrothermal factors in Ningxia, an arid and semi-arid area in Northwestern China, were examined to determine their influence on the geographical differentiation of the wool quality of Tan sheep lambskin. Prospective areas for extension of the Tan sheep industry were also investigated. Two sheep groups were sampled; one consisted of artificial insemination flocks (1241 lambs sampled from 25 flocks) and the other of natural mating flocks (1009 lambs from 38 flocks). Six phenotypical traits were measured for each lamb and six hydrothermal factors were collected from the meteorological stations located in the sampling areas. A significant correlation was found between wool characteristics of the lambskin and hydrothermal conditions. Data further indicated that among all the hydrothermal factors measured, those causing the geographical differentiation of soil and vegetation were the major factors responsible for the corresponding differentiation of the lambskin and wool quality of Tan sheep. Thermal factors were mostly positively correlated with wool quality, while the influence of moisture was negative. Three eco-geographical regions were defined based on a combination of the hydrothermal conditions and corresponding wool characters: (i) typical region or super-suitable region, (ii) sub-typical region or suitable region and (iii) transitional region. The delimitation could be used as a basis for the extension of the Tan sheep industry. It is also suggested that the wool quality of lambskin of Tan sheep in these three regions could be improved by means of controlled breeding and selection.