Pehlivan Erkan, Kaliber Mahmut, Konca Yusuf, Dellal Gürsel
Department of Animal Science, Faculty of Agriculture, Ankara University, Ankara 06110, Turkey.
Department of Animal Science, Faculty of Agriculture, Erciyes University, Kayseri 38039, Turkey.
Asian-Australas J Anim Sci. 2020 May;33(5):848-855. doi: 10.5713/ajas.19.0400. Epub 2019 Oct 21.
Shearing is one of the practices that is applied periodically to fiber producing animals, which can also alter resistance of animals to high temperatures in especially summer months. This study aimed to investigate effects of shearing on some physiological and hormonal parameters in Akkaraman sheep during summer season.
This study was carried out on 39 non-pregnant Akkaraman ewes (aged 1.5 years at the beginning of experiment). The 39 ewes were chosen randomly from the flock belonging to the Erciyes University and they were assigned to two groups as follows: i) group A (n = 20) designed as the control group, they were shorn and group B (n = 19) designed as the experimental group, they were unshorn. Prior to the shearing (-1 day) and on days 1, 7, 15, 30, 45, 60, 75, and 90 following the shearing, blood samples were taken from the vena jugularis of each sheep. Cortisol, β-endorphin, growth hormone (GH), thyroxine (T4), triiodothyronine (T3), and heat shock protein 70 (HSP-70) concentrations were determined using the enzyme immunoassay method. Body weight (BW), rectal temperature (RT), pulse rate (PR), and respiratory rate (RR) of each sheep were recorded at the same time. The data obtained were analyzed using two-way repeated measures analysis of variance.
Statistical analysis showed a significant effect of shearing×period interaction (p<0.01) and a significant effect of period (p<0.01) on BW, HSP-70, cortisol, T4 and RT, PR, GH, β-endorphin, T3, respectively. Also these analysis showed no significant effect of shearing× period interaction or period on RR.
The results showed that the thermoregulation abilities of sheep were affected by shearing treatment and the shorn ewes were less affected by heat stress. In conclusion, based on the data of this study, shearing can be considered as a necessary management practice that requires protection for sheep from the effect of heat stress.
剪毛是定期应用于产毛动物的一种操作，在夏季等特殊时期，它还会改变动物对高温的抵抗力。本研究旨在调查夏季剪毛对阿卡拉曼绵羊某些生理和激素参数的影响。
本研究以39只未怀孕的阿卡拉曼母羊（实验开始时年龄为1.5岁）为对象。这39只母羊从埃尔西耶斯大学所属的羊群中随机选取，并分为以下两组：i）A组（n = 20）作为对照组，进行剪毛；B组（n = 19）作为实验组，不进行剪毛。在剪毛前（-1天）以及剪毛后的第1、7、15、30、45、60、75和90天，从每只羊的颈静脉采集血样。采用酶免疫分析法测定皮质醇、β-内啡肽、生长激素（GH）、甲状腺素（T4）、三碘甲状腺原氨酸（T3）和热休克蛋白70（HSP - 70）的浓度。同时记录每只羊的体重（BW）、直肠温度（RT）、脉搏率（PR）和呼吸率（RR）。对获得的数据采用双向重复测量方差分析进行分析。
统计分析表明，剪毛×时期交互作用（p<0.01）以及时期（p<0.01）分别对体重、HSP - 70、皮质醇、T4以及直肠温度、脉搏率、生长激素、β-内啡肽、T3有显著影响。同样，这些分析表明剪毛×时期交互作用或时期对呼吸率无显著影响。
结果表明，剪毛处理会影响绵羊的体温调节能力，剪毛后的母羊受热应激的影响较小。总之，基于本研究的数据，剪毛可被视为一项必要的管理措施，需要保护绵羊免受热应激的影响。
