The newborn calf is born without an immune system due to the impermeability of the placenta, making high-quality colostrum crucial for the passive protection of the calf in the first days of life. Colostrum differs significantly in composition compared to milk. It contains high levels of immunoglobulins (Ig), primarily IgG, along with proteins, fats, minerals, and vitamins. The newborn calf must consume at least 3 litres of high-quality colostrum as soon as possible after birth. This ensures the successful passive transfer of immunoglobulins. Several factors affect colostrum quality, such as breed, cow age – parity, cow nutrition during the dry period, environment, calving season, dry period length, and colostrum leakage during calving. The quality of colostrum, or its Ig content, can be assessed using tools like a colostrometer, refractometer, or digital refractometer. Visual assessment is also possible, though not reliable. Based on the known quality of colostrum, we can decide whether it is suitable for feeding newborn calves. For the purpose of this thesis, we monitored colostrum quality of 13 dairy cows on a family farm during the first 10 milkings after calving. We found that the highest immunoglobulin levels were detected during the first milking post-calving. Immunoglobulin levels then rapidly decreased with each subsequent milking. In our study, the highest immunoglobulin content was found in crossbred cows.
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