# Effects of Polymorphism of the Growth Hormone Receptor (GHR) Gene on the Longevity and Milk Performance of White-Backed Cattle

## TL;DR

This study explores how genetic variation in the GHR gene affects the lifespan and milk production of Polish White-Backed cattle.

## Contribution

The study identifies a specific GHR gene polymorphism linked to longevity and milk performance in a unique cattle breed.

## Key findings

- GHR AluI locus variation is strongly associated with longevity parameters in Polish White-Backed cattle.
- The AA genotype was most frequent, followed by AB and BB genotypes, with distinct impacts on productivity.
- Polymorphism in the GHR gene correlates with milk yield and milk dry matter composition.

## Abstract

Longevity in farm animals often refers to productive longevity, determined by productivity and economic outcomes. Functional longevity considers factors beyond productivity, such as health and genetic traits. In dairy cattle, total longevity and functional longevity are important selection parameters. Genetic factors, like the growth hormone receptor (GHR) gene, influence longevity and milk production traits. The Polish White-Backed breed, with unique genetic variants, was studied for GHR gene polymorphism and its association with longevity and milk performance. The study found a strong link between GHR AluI locus variation and longevity parameters, suggesting potential applications in breeding for improved longevity and productivity. Further research should include more individuals and breeds to validate these findings.

Longevity is a trait influenced by numerous factors, including environmental factors, animal health, and productivity, which translate into economic considerations. In addition to many others, genetic factors are also very important. One of the genes indirectly associated with longevity parameters is the growth hormone receptor gene (GHR). Therefore, an attempt was made to link polymorphism in the 5’UTR region of the GHR gene with longevity and productivity parameters, as well as the content of individual components of milk dry matter. The study was conducted among 100 individuals of the Polish White-Backed breed, covered by genetic resources conservation. The PCR-RFLP method was used. The 836 pz product was digested with the restriction enzyme AluI, and three genotypes were identified: AA, AB, and BB, with frequencies of 0.60, 0.32, and 0.08, respectively. The results obtained were compared with the utility parameters of the animals, and the following indicators were estimated: herd life, productive life, and milking life. The conducted research shows that GHR AluI polymorphism is associated with indicators of longevity, the number of milking days, milk yield, and the content of individual components of milk dry matter.