The future of the dairy herd is dependent on the production of superior heifers to replace culled lactating animals. Therefore, it is imperative that the health status of the replacement animal is optimized to present a healthy first calf heifer to the lactating herd. Studies have consistently demonstrated the detrimental effects of pneumonia in calves on age at first calving and on milk production once these animals enter lactation. Calves with respiratory infections were twice as likely to leave the herd and age at first calving was delayed by 6 months when compared with calves that did not experience respiratory disease or pneumonia. In another study, calves treated for scours were three times more likely to calve at 30 months of age or greater.

Raising dairy replacement heifers is expensive. In fact, if the dairy is divided into different enterprises (eg. labor, feed cost for lactating cows, facilities, etc.), rearing replacements is the second largest cost, behind feed cost for lactating cows. The percentage will vary from farm to farm, but approximately 9% to 20% of the expenses incurred will involve rearing and developing heifers. Therefore, heifers should represent a sound investment, as their impact on future herd profitability is enormous.

Animal agriculture is facing the significant issue of managing excreted nutrients, and researchers are designing programs to address the issue. The intense management of animals in the poultry, swine, and dairy industries can contribute to environmental pollution. Although there are more beef than dairy cattle in Virginia, beef cattle are typically maintained on pasture and dispersed over a greater area. Feed management in dairy cows to reduce nutrient consumption has been identified as being very effective in reducing output of potentially polluting nutrients such as nitrogen and phosphorus.

Several factors can dramatically reduce replacement-rearing cost and increase potential profits for the producer: (1) maximizing immunity from colostrum to minimize mortality and sickness, (2) formulating rations for specific weight gains during strategic periods of development and avoiding over-fattening prior to puberty because it impairs mammary development, (3) formulating rations for an average daily gain of 1.8 lb. for Holstein heifers, (4) using AI sires ranking in the top 20% for (PTA$) to optimize genetic improvement, (5) monitoring age, body weight, wither height, body condition score as well as peak milk and ME milk yield of first lactation heifers to evaluate management at first calving, and (5) controlling the size of the replacement herd by calving heifers at 24 months and raising no more than needed.