Review: Mammary gland physiology and modulation during colostrogenesis in dairy goats

Newborn ruminants are highly dependent on the intake of high-quality colostrum immediately after birth to obtain energy and achieve an appropriate immunisation. Previous research indicates that poor management practices in the last months of gestation can lead to increased neonatal mortality rates by reducing colostrum quality among other factors. In ruminants, colostrum synthesis is a well-preserved mechanism which has been speculated to be regulated by the neuroendocrine system. However, this review aims to explore different approaches such as alternative dry-off management practices, the inclusion of different nutrients on prepartum diets, and the stimulation of the mammary gland immune response to modulate colostrogenesis and consequently, to enhance colostrum quality. Ensuring correct dry-off practices combined with controlled dietary supplementation can support mammary gland reorganisation and potentially modulate colostrogenesis. Despite positive effects on colostrum yield, the bioactive composition of colostrum seems to be irresponsive to prepartum energy, protein, and fat supplementation in dairy goats. On the other hand, mastitis has obvious negative effects on animal health; however, an experimentally induced local inflammation seems to trigger helpful modifications on the blood-milk barrier, enhancing the concentration of some immune components (i.e., immunoglobulin G and M) in goat colostrum. Yet, most research has focused on dairy cattle, leaving a significant knowledge gap on colostrogenesis in small ruminants. Therefore, future studies should focus on developing novel dry-off and dietary strategies to not only promote a healthy lactation but also to guarantee a successful colostrum synthesis.