Rapid Communication: Colostrum immunoglobulin concentration in mammary quarters is repeatable in consecutive lactations of dairy cows.

Colostrum IgG concentration and yield vary tremendously among farms and cows and among quarters within cows. The present study quantified changes in quarter colostrum characteristics up to 3 successive lactations. First colostrum was quarter collected within 4 h after parturition in the first 2 consecutive lactations from 12 cows, and colostrum was obtained from 14 multiparous dairy cows in 2 consecutive lactations and 8 cows thereof in 3 consecutive lactations. Colostrum yield per quarter showed a high variation in both primiparous and multiparous dairy cows during consecutive lactations. Percentage distribution of colostrum yield among quarters within cows was similar from parity to parity. The differences in colostrum yield within the same quarter were higher in cows from the first to the second lactation compared with the differences within quarters of multiparous cows in consecutive lactations (P < 0.05). The intraclass correlation coefficient (ICC) for quarter colostrum yield was found to be similar in cows from the first to the second parity (ICC = 0.42) and within consecutive lactations of multiparous cows (ICC = 0.44). Whereas the position of the quarter did not influence colostrum yield in cows from the first to the second lactation, quarter colostrum yield in multiparous cows was higher in rear quarters than in front quarters (P < 0.05) with fewer changes in successive lactations. Concentration and mass of IgG in quarter-milked colostrum distinctly varied among quarters and cows in both primiparous and multiparous cows. In multiparous cows, higher values for quarter concentration and mass of IgG were observed when compared with primiparous cows, in particular in the rear quarters (P < 0.05). Relative differences of IgG concentration and mass within quarters were higher in consecutive lactations of multiparous cows compared with differences within quarters of cows in the first 2 lactations (P < 0.05). The ICC of colostral IgG concentration and mass within quarters of cows from the first to the second lactation was 0.52 and 0.67, respectively, and lower compared with the ICC of IgG concentration and mass within quarters during consecutive lactations of multiparous cows. In conclusion, IgG concentration and mass were shown to be more repeatable within quarters of multiparous dairy cows compared with the first 2 lactations of dairy cows. Contrarily, colostrum yield within quarters in consecutive lactations had only a moderate repeatability and seemed to be affected by factors other than genetics. [ABSTRACT FROM AUTHOR]