Clinical and morphological characteristics of musculoskeletal system pathologies in sheep with endemic goiter in the Republic of Khakassia

Abstract

Systemized data on musculoskeletal system morphofunctional changes of sheep with endemic goiter in the Republic of Khakassia are discussed. The research goal was to reveal the features of clinical and morphological disorders, to conduct quantitative evaluation of the structural and functional transformations of animal bone tissue. The research targets were 44 sheep with clinically apparent endemic goiter and hypothyroidism in the age groups of 0-10 days, 4-6 months, 2 years and older. The data was obtained by surgical and orthopedic medical examination with the evaluation of the forage supply. The following methods were used: examination, diagnosis of lameness, palpation and percussion of the musculoskeletal structures of the extremities, macroscopic morphometry of the femur and bone mass index. The research identified 44 (100%) animals with different types of osteoarthropathy which accounted for 7.24% of the total sheep population. Significant age-related features of the course and symmetry of the limb girdles damage were revealed. At the age of 0-10 months, the presence of congenital rickets (100%) was typical. At 4-6 months, disruption of bone growth processes during hypothyroidism appeared as osteodystrophy; at 2-4 years - ulcerative pododermatitis of the sole (35.7%) and inter-claw fissure (7.14%) were found. Structural and functional changes in bone tissue were expressed in delayed formation of the bone marrow cavity and ossification of the epiphyses in newborn animals; and at the age of 4 months and older - osteoporosis with fibrous degeneration in the diaphyseal zone. Systemic changes in bones, joints, and muscles are associated with a slowdown in osteogenesis and bone tissue remodeling; they are clinically expressed by secondary pathologies: rickets, osteodystrophy, osteomalacia leading to decreased bone mass, deformation of the epiphyseal growth zones like point dysplasia expressed on the pelvic limbs, softening hoof horn and purulent-necrotic pododermatitis.