Colostrum quality in Northern Italy: The role of dry cow nutrition and colostrum feeding management

This study investigated the effects of dry cow feeding on colostrum quality. A survey was conducted, and samples of colostrum and feed ingredients were collected from 25 dairy farms in Northern Italy. Colostrum was analysed for quality in terms of Brix value and gamma globulins, while diets and feed ingredients were analysed for their chemical constituents. The mean colostrum quality (n = 163) was 24.3 ± 4.41% Brix and 54.2 ± 20.8 g/l gamma globulin. The refractometer method effectively assessed colostrum quality, correlating accurately with laboratory gamma globulin measurements (R = 0.729). Factor analysis indicated that key nutrients, such as protein and fat daily intakes in dry cow diets, influenced colostrum immunoglobulin G. Furthermore, supplementation of selenium, vitamin A, vitamin B12, and vitamin E also improved colostrum quality. Colostrum feeding occurred, on average, 5.44 ± 2.63 h post-calving, with a quantity of 2.74 ± 0.71 l per meal, which is below the recommended 10% of the calf body weight. However, the maximum feeding time was 12 h, and the minimum colostrum quantity was 1.25 l, highlighting considerable room for improvement.