Effect of continuous milking on immunoglobulin concentrations in bovine colostrum

Continuous milking is defined as a dairy cattle management system without a planned dry period for cows in late gestation. Continuous milking has been described to reduce health problems common in periparturient cattle, but may affect colostrum immunoglobulin (Ig) concentration and subsequently calf health. This study reports the influence of continuous milking on Ig concentrations of bovine colostrum in commercial dairy farms. Colostrum Ig concentrations of 227 cows from 13 herds were quantified with a quantitative ELISA for IgG, IgG1, IgG2, IgA and IgM. Colostrum samples of continuous milked (CM) cows (n = 38) were compared with colostrum samples of cows (n = 189) after a traditional dry period (DP) of at least 42 days.Resultsindicated that colostrum Ig concentration was significantly lower in continuous milking systems where IgG, IgG1, IgG2, IgA and IgM concentrations were reduced by half compared with cows that had a planned dry period. When relating the results from this study to recommendations for colostrum management it can be concluded that although colostrum Ig concentrations are significantly lower in a continuous milking management system an adequate passive immune transfer can still be achieved based on colostrum quality provided colostrum feeding management is optimal.