LACTATION PHYSIOLOGY - A RUMINANT ANIMAL PERSPECTIVE

Importance of peripubertal mammary development as a foundation for subsequent mammary growth and milk production was discussed. Morphological differences in peripubertal mammary growth in rodents and ruminants were described. The relevance of tissue interactions and association with hormones and growth factors in mammary development were delineated. Data from specific studies with ruminant mammary parenchyma were outlined for comparison with rodent studies. It is concluded that the wholesale extrapolation of data from rodent studies to explain udder development is inappropriate. Lastly, recent data from experiments with culture of mammary explants from bulls is described. Pragmatically, these data suggest that responses of mammary tissue from bulls might provide a means for early selection of superior sires or provide a unique model to study tissue interactions in udder development.