Peculiarities of age-related morphological changes in the dermal-hair cover of the Pamir yak ecotype bred in the mountain zone of Northern Tajikistan

In the process of animal adaptation to changing environmental conditions, the hair cover, which is known to perform a heat-protective function primarily, plays a significant role. The hair cover of animals undergoes changes depending on the season of the year and the natural and climatic zone in which the animals live. It has its peculiarities in different species (breeds). The nature and features of the hair cover of animals are often used by scientists to compile zoological systematics, assess the health and constitution types of animals, their acclimatisation ability, etc. In this article, the authors reviewed age-related changes in weight, size, thickness and tightness of animal skins (changes in skin thickness from the ridge to the floor) and features of the hair cover of the skin’s yaks of Northern Tajikistan. The authors also noted that in all animals, the weight of hides increases in proportion to the rise in live body weight. The absolute importance of skins, up to the age of half a year of yaks, is almost two times higher than cattle. In yaks at one- and three years old, the thick- ness of skins at the standard point in these animals is somewhat comparable. But the thickness of the pelts in the collar and area of hiding yak next to the floor remains higher by about 25-40%. Yaks are known to have three main categories of hair: long hairs (in the abdominal region of the hide and on the tail), short hairs (on the rump, neck and back) and down inches (in all parts of the animal’s fur). Long coats are also the thickest. The hair length of newborn yaks is 187.60±2.66 mm, of one-year-old yaks 452.50±2.52 mm, and of six-year-old yaks, it reaches 475 mm. The authors determined the total amount of hair of different categories in the three topographic parts of the body: in the rump, the sum of hair is 1545 hair units; in the collar part, the sum of hair is 1590 hair units; in the abdominal area of the body the sum of hair is 1770 hair units. The collar and rump do not have long hairs, unlike the abdomen. Downy hairs are characteristic of all parts of the hide but predominate in the scruff and collar. The dynamics of age-related changes in the hair cover of yaks have been determined.

1. Dambinimaeva B.Ts., Rabzhaeva E.Ts., Mezhdunarodnyy shkol’nyy nauchnyy vestnik, 2016, No. 1, pp. 13–16 (In Russ.).

2. Bobokhodzhaev R.I., Tovarovedcheskoe kachestvo kozhnogo pokrova krupnogo rogatogo skota Tadzhikistana (Commodity quality of the skin of cattle in Tajikistan), Dushanbe: Irfon, 2008.

3. Nezavitin A.G., Zakharov N.B., Kobtsev M.F., Problemy sel’skokhozyaystvennoy ekologi (Problems of agricultural ecology), Proceedings of the Conference, Novosib. gos. ag-rar. un-t, Novosibirsk, 2000, pp. 44.

4. Mukhiddinov A.R., Kamolov N.Sh., Bobokhodzhaev R.I., Vozrastnye osobennosti i mofo-fiziko-khimicheskie izmeneniya kozhnogo pokrova pamirskogo ekotipa yakov, razvodimykh v gornoy zone Severnogo Tadzhikistana (Age features and morpho-physico-chemical changes in the skin of the Pamir ecotype of yaks bred in the mountainous zone of Northern Tajikistan), Dushanbe: Irfon, 2020, 186 p.

5. Irgashev T.A., Shabunova B.K., Kosilov V.I., Gerasimenko V.V., Izvestiya Orenburgskogo gosudarstvennogo agrarnogo universiteta, 2016, No. 5(61), pp. 113–115.

6. Soatov S.S., Amirshoev F.S., Izvestiya Akademii nauk Respubliki Tadzhikistan. Otdelenieya biologicheskikh i meditsinskikh nauk, 2017, No. 2(197), pp. 79–85.

7. Mataru Kh.S., Karamaeva S.V., Karamaeva A.S., Mezhdunarodnyy nauchno–issledovatel’skiy zhurnal, 2016, No. 3(45), pp. 112–115.

8. Zimin P.V., Sravnitel’naya morfologiya kozhno-volosyanogo pokrova u nekotorykh vidov domashnikh i dikikh kopytnykh zhivotnykh (Comparative morphology of the skin-hair cover in some species of domestic and wild ungulates), Extended abstract of candidate΄s thesis, Saratov, 2006, 22 p.

9. Lykhina L.Yu. Opredelenie vida zhivotnykh po strukture volosa (Determination of the type of animal by the structure of the hair), Extended abstract of candidate΄s thesis, Bishkek, 2011, 23 p.

10. Patil A.D. [et al.], Histology of the skin with special reference to the effect of external cooling in buffalo calves, Indian veter. J., 1989, Vol. 5, pp. 432–434.

11. Saravanakumar V.R., Thiagarajan M., Comparison of sweat glands, skin characters and heat tolerance coefficients among Murrah, Surti and non-descript buffaloes, Indian J. Anim. Sci., 1992, Vol. 7, pp. 625–628.

12. Singh S.P., A few physiological parameters of yaks, Indian J. Animal Sci, 1989, Vol. 9, pp. 1108–1109.

13. Cheng Peilien (Zheng Pilin). Yak (types) Livestock breeds of China, FAO animal production and health paper, Rome, 1984, pp. 96–108.

14. Pozdnyakova V.F., Soboleva O.V., Smirnova I.A., Bravilova E.A., Sovremennye problemy nauki i obrazovaniya, 2015, No. 4, pp. 506.

15. Mukhiddinov A.R., Bobokhodzhaev R.I., Niyazova R.K., Problemy ustoychivogo razvitiya proizvodstva pishchevykh produktov v Tsentral’noy Azii (Problems of sustainable development of food production in Central Asia): Proceedings of the Conference, Khudzhand, 2013, pp. 142.