Mastitis in Dairy Heifers: The Damage We Cannot See

摘要

Over the past 30-40 years a gradual, but significant, change in the dairy industry's mindset has occurred in how we view udder health in replacement dairy heifers. Historically, heifers were viewed as "sterile" dairy animals that were unburdened withthe udder health challenges that encumber the lactating dairy herd. Thankfully, this mindset has changed and heifer mastitis is now recognized as an important issue needing attention. The importance of this issue is emphasized when it is recognized thatreplacement heifers represent considerable financial investments from the producer and comprises the basis of the herd's genetic progress and future milk production. Therefore, improving udder health in heifers is an important focus when it comes to improving the animals' udder health and productivity in today's modern dairy industry. Examples of this change in mentality and the concerted effort to reduce heifer mastitis are abundant in the literature. Despite these efforts, a lack of understanding andthe implication of intramammary infections (IMI) in dairy heifers is sometimes lost on producers, industry professionals, and researchers alike. The purpose of this article is to grossly summarize the prevalence of IMI in dairy heifers and provide an in-depth look on how such IMI affect the dairy heifer's mammary gland and implications for future milk production.