The role of somatotropic axis genes in regulating the productivity traits of dairy and beef cattle (review)

Somatotropin plays a crucial role in regulating growth, metabolism, and development in cattle. This hormone acts through a complex network of protein interactions known as the somatotropic axis, which coordinates metabolic and physiological processes in mammals. The aim of this review is to systematize current data on the influence of somatotropic axis genes (GH, GHR, IGF-1, etc.) on cattle productivity (both dairy and beef traits) and assess their potential use in livestock breeding programs. Numerous allelic variants of genes associated with the somatotropic axis significantly impact key economic indicators, such as milk yield and composition, carcass characteristics, meat production levels, and reproductive performance. Genetic variants of the GH gene affect parameters including milk yield, fat and protein content, and lactation efficiency. For example, certain genotypes (e.g., GHLL) may increase milk production but reduce fat and protein content, while others (GHVL) can enhance milk fat while decreasing overall yield. Interactions between GH and other genes also play a key role in determining dairy productivity. Recombinant bovine somatotropin (rBGH) is widely used to enhance productivity in dairy cattle, particularly during mid-to-late lactation, by activating mechanisms that improve milk and meat yields. Despite extensive existing research, studies on the genetic variability of the growth hormone gene across different cattle breeds remain relevant and in demand. In this context, the development of personalized rBGH administration protocols-tailored to the genetic profiles of animals-aims to maximize productivity while maintaining animal health and product quality. This necessitates comprehensive research to determine optimal dosages, administration regimens, and their effects on the physiological state of animals with different genotypes throughout their productive cycles.