Sources of variation and prospects for improvement of productive efficiency in the dairy cow: a review

• Published in: Journal of animal science Vol. 60; no. 2; p. 583
• Main Authors: Bauman, D.E, McCutcheon, S.N, Steinhour, W.D, Eppard, P.J, Sechen, S.J
• Format: Journal Article
• Language: English
• Published: United States 01.02.1985
• Subjects: Animal Feed - economics; Animals; BOVIN LAITIER; Cattle - metabolism; COWS; DAIRY CATTLE; DIGESTION; EFFICACITE; EFFICIENCY; EFICACIA; Energy Metabolism; Enzymes - metabolism; Female; GANADO DE LECHE; HOMEOSTASIS; Hormones - blood; LACTACION; LACTATION; Milk - metabolism; NUTRIENTES; NUTRIENTS; Nutritional Requirements; Pregnancy; SUBSTANCE NUTRITIVE; VACA; VACHE
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/jas1985.602583x

In this review, "productive efficiency" in dairy cows is defined as the yield of milk obtained in ratio to the nutritional costs associated with maintenance, milk synthesis and loss of body condition during lactation. Improvements in efficiency could occur as a result of changes in digestion and nutrient absorption, maintenance requirement, utilization of metabolizable energy for production or nutrient partitioning. Digestibility can be greatly enhanced by appropriate dietary manipulation. Likewise, it may be possible to reduce maintenance requirements and improve the efficiency with which metabolizable energy is used for milk synthesis by manipulation of the pattern of nutrients presented to tissues. However, these factors apparently do not respond to selection for increased milk yield, and little variation is observed among cows. In contrast, individual cows differ substantially in feed intake and in the partitioning of nutrients among body tissues. Techniques associated with genetic engineering and the early prediction of genetic merit have the potential to improve productive efficiency by manipulation of these processes. However, changes in nutrient partitioning and feed intake during lactation are coordinated by a complex network of controls that accommodate the nutrient requirements of each tissue while maintaining homeostatic balance. Future improvements in productive efficiency will therefore depend on our ability to understand the manner in which these controls operate.