Date Received: 09-03-2020 / Date Accepted: 08-04-2020
The study aimed to evaluate the effect of cow breed, lactation cycle, lactation stage and protein beta-casein (β-CN) variant on milk composition (protein, fat and solid non-fat). A total of 81 milk samples were collected from 81 dairy cows, including Holstein Friesian (HF) and crossbred cattle (¾ HF and ⅞ HF) and the details of lactation cycle number and lactation stage were provided by the dairy farmers. Protein β-CN variants were identified using ultra-high-performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS). Protein, fat and total solid content were determined using Kjedahl, Gerber and the drying method. Cow breed and lactation stage significantly influenced protein and fat contents but insignificantly impacted on solid, not fat. Lactation cycle and protein β-CN phenotype were not significantly associated with milk composition.
