A Systematic Approach to Calf and Heifer Rearing: “Intensified” Feeding and the Target Growth System

Growth is an essential component of the dairy enterprise, yet many of us that work in the dairy industry have had little training or background in applied aspects of animal growth. We are more comfortable with concepts involving milk yield and composition primarily because that is where we generate income. However, to improve calf and heifer management, we must understand basic concepts of applied growth so that better recommendations can be developed. For several years our laboratory has been investigating nutritional and management practices of calves and heifers in an effort to reduce the age at first calving. Interest in this area stems from several factors, primary of which is the economic investment required for the heifer replacement program by the dairy industry which is equivalent to 15 to 20 % of the cost to produce milk. Our research group made several observations that precipitated a series of ongoing experiments that will be discussed in this paper. Those observations were: 1) Studies that have investigated pre-pubertal “accelerated growth ” in an effort to lower age at first calving never started treatments earlier than 3 months of age and most were well into the ruminant phase of growth and as late as 8 months of age. Thus, from a systematic perspectiv