Age dynamics of morphometric parameters in female silver-black foxes (Vulpes vulpes)

This study investigates morphometric variability in female silver-black foxes (n=50/age group) at 3 and 7 months of age, conducted at OOO “Fur Farm Vyatka”. The study aimed to analyze the age dynamics of body structure and identify key factors determining growth during critical developmental periods. Principal Component Analysis (PCA) was employed to process data for 13 linear and weight parameters. The results revealed two main factors that collectively account for 76.8% of the total trait variability. At three months of age, the total body size factor dominates (49.99% of the variance), integrating the growth of all linear traits (body length: 0.922; tail length: 0.897; chest girth: 0.881; body weight: 0.828). This pattern is characteristic of isometric growth during early ontogenesis under the control of the somatotropic axis (GH-IGF-1). By seven months, the structure of variability changes fundamentally. The first component (39.60%) reflects the prioritized development of axial structures, while the second component (33.67%) demonstrates allometry, contrasting chest width (0.937) against forelimb length (–0.889) and head length (–0.786). It was established that these changes are a direct consequence of hormonal shifts: estrogen activation inhibits the linear growth of limbs while stimulating the development of the trunk backbone and the accumulation of energy reserves. This transition represents an adaptive strategy aimed at preparing the female organism for its first reproductive cycle. The findings have practical significance for optimizing the management and nutrition of young fur-bearing animals in commercial fur farming.

1. Shevchuk T.V. Biological features silver fox. APRIORI. Seriya: Estestvennye i tekhnicheskie nauki. 2015;(5):34. (In Russ.)

2. Berestov V.A. Laboratory methods for assessing the condition of fur-bearing animals. Petrozavodsk, USSR: Karelia, 1981:198. (In Russ.)

3. Balhanovskaya T.V. Dependence of the blood biochemical indices silver-black foxes on the season in the north of Tyumen. Fundamentalnye issledovaniya. 2013;(4-5):1 120-1123. (In Russ.)

4. Berezina Yu.A., Koshurnikova M.A., Domskiy I.A. Female foxes (Vulpes vulpes L.) of different color types with age. Krolikovodstvo i zverovodstvo. 2022;(4):20-27. (In Russ.) https://doi.org/10.52178/00234885_2022_4_20

5. Salt C., Morris P.J., Butterwick R.F., Lund E.M. et al. Comparison of growth patterns in healthy dogs and dogs in abnormal body condition using growth standards. PLoS ONE. 2020;15(9): e0238521. https://doi.org/10.1371/journal.pone.0238521

6. Shumilina N.N., Larina E.E. Features of growth and development of puppies of a golden and white generation of a raccoon dog. Veterinariya, zootekhniya i biotekhnologiya. 2018;(3):48-54. (In Russ.)

7. Balakirev N.A., Larina E.E., Shumilina N.N. Comparative analysis of the dynamics of live weight of young foxes of silver-black, colicotta, pearl, Burgundy foxes, taking into account feed consumption. Vestnik Altayskogo gosudarstvennogo agrarnogo universiteta. 2011;80(6):46-49. (In Russ.)

8. Khodusov A.A., Ponomareva M.E., Konoplev V.I. Morphometric parameters of scanblack males with different geno- and phenotypes. Agricultural Bulletin of Stavropol Region. 2021;(4(44)):15-20. (In Russ.) https://doi.org/10.31279/2222-9345-2021-10-43-15-20

9. Orlova E.A., Paraskiva E.E., Fedorova O.I. Changes in some exterior and interior indicators of sables in the process of their industrial breeding. Krolikovodstvo i zverovodstvo. 2023;(5):15-23. (In Russ.) https://doi.org/10.52178/00234885_2023_5_15

10. Khalafyan A.A. Modern methods of multidimensional statistical analysis. Moscow, Russia: Lan, 2020:456. (In Russ.)

11. McGarigal K., Cushman S., Stafford S. Multivariate statistics for wildlife and ecology research. New York, USA: Springer, 2018:283.

12. Zelditch M.L., Swiderski D.L., Sheets H.D. Geometric morphometrics for biologists: a primer. London, UK: Elsevier, 2014:443.

13. Rincon M., Rudin E., Barzilai N. The insulin/IGF-1 signaling in mammals and its relevance to human longevity. Experimental gerontology. 2005;40(11):873-877. https://doi.org/10.1016/j.exger.2005.06.014

14. Smirnov V.V., Vykhristyuk O.F., Gavrilova A.E. Berezina, D.E. Tallness syndrome: differential diagnosis. Lechaschi Vrach. 2012;(3):10-15. (In Russ.)

15. Frynta D., Baudyšová J., Hradcová P., Faltusová K. et. al. Allometry of Sexual Size Dimorphism in Domestic Dog. PLoS ONE. 2012;7(9): e46125. https://doi.org/10.1371/journal.pone.0046125

16. Väänänen HK, Härkönen PL. Estrogen and bone metabolism. Maturitas. 1996;(23):565-569. https://doi.org/10.1016/0378-5122(96)01015-8

17. Berezina Yu., Koshurnikova M., Bespyatykh O., Syutkina A. et al. Growth rate of red fox puppies of Vyatka fire type. Genetika i razvedenie zhivotnykh. 2023;(2):20-27. (In Russ.) https://doi.org/10.31043/2410-2733-2023-2-20-27

18. Jaiswar S, Priyadarshini A. Leptin and Female Reproductive Health. IntechOpen. 2021. https://doi.org/10.5772/intechopen.101226

19. Zhan Y.M., Yasuda J., Too K. Reference data on the anatomy and serum biochemistry of the silver fox. Japanese Journal of Veterinary Research. 1991;39(1):39-50.

20. Zatoń-Dobrowolska M., Moska M., Mucha A., Wierzbicki H. et al. Variation in fur farm and wild populations of the red fox, Vulpes vulpes (Carnivora: Canidae) – Part I: Morphometry. Canadian Journal of Animal Science. 2016;(96):589-597. https://doi.org/10.1139/CJAS-2016-0026

21. Sherratt E., McCullough E., Painting C. Commentary: The ecological and evolutionary implications of allometry. Evolutionary Ecology. 2022;36:431-437. https://doi.org/10.1007/s10682-022-10201-9

22. Walther A., Seuffert J. Testosterone and Dehydroepiandrosterone Treatment in Ageing Men: Are We All Set? World Journal of Men’s Health. 2020;38(2):178-190. https://doi.org/10.5534/wjmh.190006

23. Orlova E.A., Zotova A.A., Fedorova O.I. Reproductive capacity of annual female sables different birth dates. Krolikovodstvo i zverovodstvo. 2021;(5):10-15. (In Russ.) https://doi.org/10.52178/00234885_2021_5_10

24. Larina E.E., Kudryavtsev V.B., Shumilina N.N. Analysis of the quality of the fur products of silver-black foxes of the Savvatievo Animal Breeding Plant. Krolikovodstvo i zverovodstvo. 2021;(5):4-9. (In Russ.) https://doi.org/10.52178/00234885_2021_5_4