An updated and comprehensive review on the composition and preservation strategies of bovine colostrum and its contributions to animal health

Colostrum is the first mammary gland secretion after parturition. Colostrum has a high nutritional value due to its contents of macronutrients, micronutrients, and bioactive compounds, and colostrum intake could improve growth performance, gastrointestinal tract development, and health status. Thus, this review focuses on the nutritional composition of bovine colostrum and its health benefits on newborn calves. Until now, the main colostrum constituents that have been more studied are macronutrients such as carbohydrates, fats, proteins, and micronutrients like vitamins, minerals, and growth factors as they provide the following health benefits to calves: boost immunity, prevent infections, treat diarrhea, and promote gut health. In addition, this review focuses on studying different preservation methods for colostrum that are useful when fresh colostrum is less or unavailable. Colostrum can be preserved using different strategies, such as the use of chemical additives, pasteurization, refrigeration, freezing, freeze- and spray-drying, which can be used to preserve colostrum. On the other hand, the best preservations methods are freeze-drying, spray drying, and freezing as they can keep the quality and availability of colostrum nutrients such as immunoglobulins and leukocytes. Future studies should focus on the feeding impact of stored colostrum and its nutrient composition especially immunoglobulins or other bioactive components to understand better what is the best preservation conditions for keeping colostrum nutrient composition in on-farm conditions.