Structure, functions and features of heavy metals and trace elements accumulation in domestic dogs coat of different breeds

The aim of the study is to investigate the macromorphological structure and specificity of microelement accumulation in the coat of domestic dogs of different breeds. Objectives: hair samples of dogs of different breeds were studied for regrowth rate, the level of microelements in biosubstrates was studied. An experi-ment was conducted on dogs owned by private owners and those who sought help from a veterinary clinic in Moscow. The studies were carried out at the Russian Biotechnology University (ROSIBIOTECH) from 2022 to 2023 using a range of modern biological, ecological and statistical methods on animals of the fol-lowing breeds: long-haired – Yorkshire Terrier, English Cocker Spaniel, Chihuahua; medium-haired – Alaskan Klee Kai, Alaskan Malamute, German Shepherd, Black Terrier, Bernese Mountain Dog, Australian Shepherd, crossbreed; short-haired – Argentine Dogo, French Bulldog, American Stafford Terrier, Dachs-hund. The guard hairs make up 75 % of the dog's coat. Its structure varies depending on the breed. The most common is the spindle-shaped hair shaft. The scaly layer formed by keratinocytes is not pig-mented. The scaly layer type of dog hair is tuberous. The cortex layer makes up 90 % of the hair volume and is responsible for its elasticity. The medullary layer of dog hair has an average thickness of 54.8 %. The average diameter of the hair of domestic dogs was (91.4 ± 11.2) μm, the indicator varied significantly with different thicknesses and depending on the breed of dogs within the range of 80 to 115 μm. The ave-rage hair regrowth rate per month was (10.6 ± 2.4) mm depending on the breed of dogs and the length of the coat. Analysis of the content of trace elements in animal hair revealed the high ability of biological sub-strates to accumulate elements. Centile scales of element accumulation were developed.