A study of the compression and resilience of Zandi sheep wool and their relationship with other fiber properties

In our country, the main goal of sheep breeding is to produce and supply meat, and other products are of secondary importance. In addition, due to the great importance of sheep meat in Iran and on the other hand due to the lack of sufficient information about the industrial breeding of sheep, most of the sheep breeders cross the meat breed with other breeds, which has caused most of the sheep in Iran to develop their own special condition. In terms of production traits, they are lost and become impure. In the past, the Zandi breed of sheep was known as a skin breed, but in recent decades, the meat weight of all the sheep breeds in Iran, As a result of mixing and crossbreeding, different breeding and maintenance methods and different weather conditions, sheep's wool has differences in terms of diameter, length, thickness and other quantitative and qualitative characteristics. Although wool is used in a wide range of uses, the characteristics that are most important are diameter, length, thickness, density, efficiency, fat, resistance, elasticity or reversibility, coefficient of variation, standard deviation. variety of diameter of wool threads, color, modulation and softness factor. Wool weight, staple length, length, fiber diameter, density of follicles and the ratio of secondary to primary follicles are different between breeds and reflect the characteristics of each breed. In general, breeds with higher follicular density produce finer fibers (Pearson et al., 1999). Resistance and elasticity are among the important features of carpet creams and also the production of fur from the skin of the Zandi breed, which have been investigated in this research.
In order to investigate some characteristics of Zandi sheep wool, information from the breeding station of Zandi sheep was used to identify and evaluate the factors affecting wool fiber characteristics in Zandi sheep of Jihad Agriculture of Tehran (Khajir station). This information includes animal number, wool sample number, gender, year and month of birth of the animal, type of birth (single or twin). A number of 105 sheep of the Zendi breed were sampled in two consecutive years . Then, in the wool and leather technology laboratory, a number of traits were evaluated on the wool samples. Data analysis was done using SAS statistical software and phenotypic correlation between traits and Pearson's correlation coefficient were calculated for wool traits. The length of the staple was determined according to Iran's standard number 1941. This step was performed in accordance with ASTM standard No. D2130 (Farhoush, 2012). After drying the wool samples, a portion of the wool that had been degreased was cut. In order to measure the diameter of the types of threads in the tested sample, the microscopic reflection method and the microprojector device were used. The microprojector is equipped with a 12/5 eyepiece lens and an X40 objective lens that creates a precise image with X500 magnification.
The aim was to study some characteristics on Zandi sheep’s breed and the effect of various factors on wool quality including sex, year of birth, birth month, type of birth and the year of sampling. Samples were taken from 105 Zandi sheep during two years. The analysis were carried out with SAS Statistical software. Phenotypic correlation between characteristics and Pearson correlation coefficient were calculated for wool characteristics. Furthermore, the regression between compression and resilience, as new traits of Zandi sheep, were examined for wool characteristics and linear pattern was obtained for compression. The mean and standard deviation for staple length (SL), mean fiber diameter (MFD), standard deviation of fiber diameter (SDF), coefficient of variation of fibre diameter (FDCV), sampling variance (SV), kemp fiber (KF), hair fiber (HF), colorful fiber (CF), fiber less than or equal to 30 microns, compression, resilience and medulation fiber (MF) were equal to 6.32 ± 1.28 cm, 31.36 ± 2.76 μ, 10.43 ± 2.02, 32.95 ± 6.05 %, 113.05 ± 43.3, 0.68 ± 0.96 %, 1.63 ± 2.71 %, 45.24 ± 26.68 %, 49.04 ± 12.73 %, 37.56 ± 7.05%, 92.81 ± 3.77 %, 47.34 ± 26.51 %, respectively. The variance analysis was carried out for year of birth, birth month, sex, type of birth and the year of sampling on above mentioned wool characteristics and between them, the effect year of sampling on compression and the effect of sex on SL was significant. The type of birth had no significant effect on any of the wool characteristics. The correlation coefficient between fiber less than or equal to 30 microns with fiber diameter was -0.86. The correlation coefficient between staple length with fiber diameter, variance, standard deviation and fiber less than or equal to 30 microns and was calculated as 0.35, 0.24, 0.26 and -26.0 respectively. Correlation coefficient between compression with fiber diameter and coefficient of variation of fibre diameter were calculated as -0.22 and 0.26, respectively. Regression between compression with fiber diameter was 0.01. The results indicated that Zandi sheep wool has some useful characteristics to use in sheep breeding programs in comparison with other native sheep breeds.
The obtained results show the relative fineness of the wool of Zandi sheep compared to other native breeds of the country and having a high breeding capacity in Zandi sheep and phenotypic diversity for proper exploitation. Correlated responses between traits can be used in genomic scanning programs and selection programs. In general, in research and breeding centers, correct recording and recording of data on wool traits seems necessary. Considering that the percentage of colored fibers is high in the Zandi breed and the optimal color for the wool used in carpet weaving is white, more attention should be paid to the correction of the color of the wool in this breed.