A Review of Genetic and Non-Genetic Parameter Estimates for Milk Composition of Cattle

: This review focuses on the genetic and non-genetic parameter estimation for dairy cattle milk composition. Milk is the most widely consumed food in the world, containing proteins, fats, lactose, and various vitamins and minerals. Milk's solids content has a direct impact on both its nutritional and economic value. The milk composition trait performances had obtained in the range from 3.5±0.0038 to 6.1±0.05 for fat percentage, 3.07±0.03 to 4.7±0.09 for protein percentage, 3.3 to 5.52±1.71 for lactose content, 12.16±0.14 to 16.02±0.05 for total solid content and 8.47±0.1 to 9.37±0.24 for the solid not fat content of cow milk, respectively. The composition of cow milk is influenced by breed, animal age and health, lactation phase, nutrition, season, milking method, number of lactations, and individual cows. The heritability of milk composition trait ranged from 0.24 to 0.49±0.03 for fat percentage, 0.28 to 0.53±0.009 for protein percentage, 0.41±0.04 to 0.59 for total solid content and 0.17 to 0.68 for the solid not fat content of cow milk, respectively. The repeatability of fat, protein, total solid and solid not fat percentage of bovine milk ranged between 3.9 to 0.98, 0.4 to 0.99, 0.49 to 0.99 and 0.23 to 0.78, respectively. The genetic and phenotypic correlation between fat and solid not fat of cow milk were weakly positive (0.16±0.15, 0.06 ±0.04), whereas a strong positive relationship was found between protein content and solid not fat of cow milk (0.99±0.05, 0.67±0.03), respectively. Enhancing milk compositional quality through genetic selection based on individual performance is successful.