Radostina Stoykova-Grigorova1, Milena Bozhilova-Sakova1, Tanya Ivanova1, Tsonka Odjakova2, Katerina Stefanova3, Denis Viryanski1
1 Agricultural Academy, Institute of Animal science – Kostinbrod, 2232 Kostinbrod, Bulgaria
2 Agricultural Academy, Research center for Stockbreeding and Agriculture – Smolyan, 4700 Smolyan, Bulgaria
3 Agricultural Academy, Agrobioinstitute, 1164 Sofia, Bulgaria
Stoykova-Grigorova, R., Bozhilova-Sakova, M., Ivanova, T., Odjakova, Ts., Stefanova, K. & Viryanski, D. (2026). Quantitative trait loci related to milk productivity in dairy cattle. Bulg. J. Agric. Sci., 32(3), 715–722
Cattle breeding is an important sector of agriculture, providing raw milk and milk products to constantly growing interest and demands of the consumers. Milk productivity is genetically determined, but this trait is also strongly influenced by environment. The genetic potential could be fully revealed only under optimal growing conditions. Identification of the genetic endowments and productive traits of farm animals, as well as the good production, is essential for any producer. Modern methods of molecular biology allow the usage of DNA markers in scientific research to identify genetic polymorphisms in gene loci and associate them with phenotypic traits. With the development of modern research in animal husbandry, it becomes possible to study the patterns of organization and function of the genome and to understand the mechanisms for the realization of genetic information in normal and pathological conditions. This data analysis was successfully applied in the development of breeding programs in animal breeding practice, aiming faster genetic progress. This review aims to follow the studies related to the evaluation of candidate genes related to milk productivity in dairy cattle. Lactation in mammals is a process that directly depends on the hormonal balance of organisms. Genetic variation in some genes such as Prolactin, Lactoferrin and Leptin has a reliable influence on the quantitative and qualitative characteristics of milk.
Milk proteins are a large group of organic compounds important for the structure and normal function of the mammalian body. Specific to cow’s milk are casein proteins, which come together in four forms (αS1-, αS2-, β- and κ-casein) and two whey proteins – α-lactalbumin and β-lactoglobulin. Genome-Wide Association Studies (GWAS), Transcriptomic Analysis, Whole-Genome Sequencing and PCR-RFLP are some of the modern methods for detecting genetic markers related to milk productivity. These approaches make it possible to find polymorphisms associated with desired productive traits.