Effects Of Age On Cashmere Performance,number And Activity Of Hair Follicles,serum Antioxidant Level Of Adult Cashmere Goats

On the basis of studying the rules of cashmere production performance with age,which reveals the mechanism of the regularity of cashmere production performance with age from the aspects of the number and activity of hair follicles,and serum antioxidant level.A total of 107 does aged from 2 to 7 years old were selected from a basic group.Cashmere samples were collected in January 2020 for analyzing the elongation length and diameter of cashmere,and cashmere production were collected in April.Blood samples of 70 cashmere goats were collected in January and June for analysis of serum antioxidant levels.Skin samples were also collected in June to analyze the number and activity of skin hair follicles.Body weight after fleecing and body weight before mating were collected from 56 cashmere goats in the basic herd in2019 to analyze the relationship between body weight gain and cashmere production performance.The cashmere production data of 3259 cashmere goat aged 2 to 7 years old in this cashmere goat farm in 2020 were collected to analyze the influence of age on cashmere production.The results showed that:1.Age had a weak negative correlation with cashmere yield(P<0.05),a strong negative correlation with cashmere elongation length,and a medium positive correlation with cashmere diameter(P<0.01).There was no significant difference in cashmere yield among different age groups(P>0.05).There were significant differences in the elongation length of cashmere among different ages(P<0.01),and the order was as follows: 2 years old > 3~4 years old > 5~7 years old.The diameter of cashmere was significantly different among different ages(P<0.01),and the fiber diameter of 5~7years old was significantly higher than that of 2~4 years old.The large group data of cashmere yield showed that there was a significant difference in cashmere yield among different ages(P<0.05).The cashmere yield between 2 to 5 years old was significantly higher than that between 6 to 7 years old(P<0.05).2.Age had a moderate negative correlation with ASFDI,ASFN,Sf:P,and a strong negative correlation with ASFD and PSf(P<0.01).There was no significant difference in the number of primary and secondary hair follicles in non-long hair period among different ages(P>0.05),but there was a significant difference in the number of active secondary hair follicles in non-long hair period(P<0.01).The orders of ASFD and ASFN: 2~5 years old > 6~7 years old,ASFDI and Sf:P: 2~6 years old > 7 years old,PSf: 2~4 years old >5~7 years old.3.Age(2 to 6 years old)had a moderate negative correlation with the activities of SOD,CAT and T-AOC in serum of Inner Mongolia cashmere goats in cashmere nongrowing period,a strong negative correlation with the activities of GSH-Px,and a moderate positive correlation with the content of MDA(P<0.01).There were significant differences in serum antioxidant levels between different ages in non-long lint period(P<0.01).The serum activities of SOD,CAT and GSH-Px were correlated with those of T-AOC at 4 years of age,> at 2~3 years,5 years and 7 years of age,and >at 6 years of age.The serum MDA content of 4 years old was lower than 2~3 years old,5 years old and 7 years old was lower than 6 years old.There was a strong negative correlation between age and serum SOD,CAT,T-AOC and GSH-Px(P<0.01),and a strong positive correlation between age and MDA(P<0.01).The serum antioxidant levels were significantly different among different ages(P<0.01).The activity of SOD,GSH-Px and T-AOC in serum were 3~5 years old > 2 years old > and 6~7 years old.CAT activity: 4 years old >3 years old and 5 years old >2 years old >6~7 years old.MDA content: 3~5 < 2 < 6~7 years old.4.Body weight gain in non-growing period was negatively correlated with age,positively correlated with cashmere yield and elongation length(P<0.01),and weakly correlated with cashmere diameter(P=0.24).There was a significant difference in body weight gain among different ages(P<0.05),body weight gain at 2 years was significantly higher than that at 3~7 years.The cashmere yield and cashmere elongation length of Inner Mongolia cashmere goats in 5~10 kg body gain group during cashmere non-growing period were higher than those in 0~5 kg group(P<0.05),and there was no significant difference in cashmere diameter(P>0.05).Conclusion: The cashmere production capacity of Inner Mongolia cashmere goats is high from 2 to 4 years old,but decreases obviously after 5 years old.The number of primary and secondary hair follicles did not change with age during the cashmere nongrowing period of Inner Mongolia cashmere goats,but the number of active secondary hair follicles decreased after 5 years.The serum antioxidant level of Inner Mongolia cashmere goats during the cashmere growing period and cashmere non-growing period decreased significantly after 5 years of age.The body weight gain is related to the cashmere yield during non-growing period,and the higher the body weight gain,the higher the cashmere yield.