[Factors influencing the quality of the first colostrum in Holstein Friesian cows and their relationship to postpartum calcium concentrations in the blood and colostrum].

OBJECTIVE: To investigate the factors that affect the quality (immunoglobulin concentration) of the first colostrum in Holstein Friesian cows and their relationship to the calcium concentrations in the blood and colostrum, with particular attention to the lactation number.

MATERIAL AND METHODS: An observational study was conducted at a commercial dairy farm (2278 Holstein Friesian cows). The analysis comprised the following variables: colostrum content of immunoglobulins and calcium, colostrum yield; blood serum concentrations of calcium, phosphate, non-esterified fatty acids, and β-hydroxybutyrate; back-fat thickness; daily milk production; calving data; lactation number; male parent of the cow; length of gestation; age at first calving; duration of the dry period; fertility parameters of prelactation; diseases during the dry period and up to 3 days postpartum. A stepwise analysis of the data for correlations and influencing factors was conducted by means of variance, correlation and multiple linear-regression analyses.

RESULTS: The mean colostral immunoglobulin concentration was 65.6 g/l with a standard deviation of 10.67 g/l. The most influential factor was the genetic background (male parent), followed by colostrum quantity and duration of the dry period. Together, these factors explained 47% of the variation of the colostral immunoglobulin content. A dominant effect of the lactation number was not confirmed. Additionally, the calcium concentrations of the blood and colostrum had no influence on colostrum quality.

CONCLUSION AND CLINICAL RELEVANCE: By selecting bulls, whose daughters give colostrum with a high immunoglobulin concentration, the colostrum quality of the herd can be increased. A high amount of colostrum and a short or a lack of a dry period can cause a lower immunoglobulin concentration. On well-managed dairy farms, a very high colostrum quality can be expected. There is only a limited possibility for improvement of the immunoglobulin concentration with respect to the indicated factors.