Annual rhythms of milk and milk fat and protein production in dairy cattle in the United States.

ABSTRACT: An annual pattern of milk composition has been well recognized in dairy cattle, with the highest milk fat and protein concentration observed during the winter and lowest occurring in the summer; however, rhythms of milk yield and composition have not been well quantified. Cosinor rhythmometry is commonly used to model repeating daily and annual rhythms and allows determination of the amplitude (peak to mean), acrophase (time at peak), and period (time between peaks) of the rhythm. The objective of this study was to use cosinor rhythmometry to characterize the annual rhythms of milk yield and milk fat and protein concentration and yield using both national milk market and cow-level data. First, 10 yr of monthly average milk butterfat and protein concentration for each Federal Milk Marketing

SUBMITTER: Salfer IJ 

PROVIDER: S-EPMC6550460 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature