Quality parameters and protein profile in raw milk from individual cows with different lactation number and breed

Abstract: Swedish dairy cows have an average life expectancy of 5 years, which means that each cow undergoes about 2.5 lactation cycles through her life. Reasons for culling dairy cows are mainly impaired fertility, udder health (mastitis) and low milk yield. Animal welfare is related to increased longevity, which in turn leads to lower greenhouse gas emissions per unit of milk, thus reduced climate impact. The aim of this study was to investigate if the number of lactations or breed, affect milk quality paramters, i.e. protein profile, gross composition, pH and somatic cell count for the two major breeds of Swedish dairy cows. For this study, 110 milk samples from SRB and SLB cows were collected in herds partcipating in an on-going research project. Results from multivariate analysis did not show any major differences in milk composition between cows with different lactation numbers. Instead, milk composition seemed to differ between cows of different breeds and between cows from different farms. Milk from SRB cows had numerically higher content of fat and total solids, and higher relative concentrations of SFA, UFA, MUFA, PUFA, C14:0, C16:0, C18:0 and C18:1C9, compared to milk from SLB cows. Additionally, milk from SRB cows had higher relative concentrations of β-CN A1and lower relative concentrations of β-CN A2, compared to milk from SLB cows. Further reasearch, including larger numbers of individual cows, is required to be able to conclude whether the number of lactations has an affect on raw milk composition.