Effects of continuous milking on bovine colostrum quality
Summary
This study reports the influence of continuous milking on bovine colostrum quality. Continuous milking has been described to reduce health problems during the dry period and parturition, but may affect colostrum quality which is essential for calf health. In this study colostrum immunoglobulin concentrations of 227 cows was quantified with a Bethyl Bovine Quantitation 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. Colostrum immunoglobulin concentration was significant lower (average IgG=24,9) after continuous milking for IgG, IgG1, IgG2, IgA and IgM (p<0,001) compared with DP-controls (average IgG= 41,5 mg/ml) for all parities. Results indicate at least 1,6 times more colostrum supply is required for providing adequate immunity to calves after continuous milking. A survey among farmers indicated presence of more health problems with calves associated with failure of passive transfer (FPT) after continuous milking. Parity differences in colostrum quality (DP-controls; n=189) was only significant for IgA for parity 1 and 2 compared to 5. Trends for increased colostrum quality for higher parities were visible, but heifers produced average quality. Colostrum samples with antibodies against Mycobacterium avium subspecies paratuberculosis (MAP) contain higher antibody concentrations (p=0,001). Colostrum volume, udder health, milking time and other factors influencing colostrum quality were discussed.