The influence of seasonal factors on the content of keratoses, free internal lipids, and physical characteristics of sheep wool

Wool formation is a complex and multifaceted process, which depend on a lot of factors, namely genetic, alimentary, animal maintenance conditions, including seasonal factors’ impact. Seasonal weather changes or so-called photoperiodism, changing the retention and feeding regimes by periods of the year, highly correlate with the physiological state of the organism of the sheep and influence the growth and quality of the wool. Given this the purpose of our work was to investigate the impact of the season on the macrostructure, chemical composition and physical properties of wool. For the research wool of ewe breed precos was used, the samples of which were taken in different seasons, in particular winter, spring, summer and autumn periods of animal maintenance. In the wool there were determined the contents of keratoses and free internal lipids, as well as the strength of the fibers at the break. It was established that wool that grew in the winter and spring period contains the largest amount of protein macro- and microfiber, i.e. alpha keratosis. Instead, with the onset of summer and until autumn the amount of this fraction decreased by an average of 2%. A similar trend was observed on the part of beta keratosis, however, these changes were less significant and did not exceed one percent. It has been established that the content of gamma keratosis, i.e. matrix of fiber, is on the highest level in summer and spring periods, that is, the periods of the best alimentary provision of animals. In the pasture period in the sheep wool there is the biggest amount of free internal lipids (1.1%). In the autumn period, their number begins to decrease gradually and the lowest one is recorded in the winter-stool period (0.9%). The most distinct seasonal changes among these lipids are fixed by cholesterol factions. In particular, the largest number of unesterified cholesterol is contained in the wool of winter growth – 67.2%. With the onset of spring the amount of this fraction decreases up to 62.3% (Р