Non-infectious newborn calf problems and survival (Proceedings)
National survey data concerning dairy calf health and survival have shown very substantial death rates over the last 10 to 15 years. The National Animal Health Monitoring System reports the number of unweaned dairy heifer calf deaths as a percentage of calves born alive to have varied from about 7.8% to 10.8 % between 1991 and 2007. Most of the causes of death reported by producers are infectious diseases, the most common being scours/diarrhea and respiratory problems. Because infectious diseases are the most prevalent calf health problems between birth and weaning, veterinarians and other dairy health advisors have placed considerable emphasis on vaccination strategies and colostrum administration as key features of calf management.
Compared with infectious disease reporting, much less emphasis has been placed on stillbirth as a cause of calf death. Death losses at delivery, or within the first 2 days after delivery, which is the commonly used definition of stillbirth in the dairy industry, are rarely the result of infectious disease. These deaths typically result from physiological derangements of newborns during delivery or during adaptation to life outside the uterus. Although these losses are less carefully tracked in the industry, current reports suggest stillbirth rates between 6 and 12%, and the NAHMS Dairy 2007 survey reports 14% stillbirth and death before 48 hrs. Therefore these losses are nearly as common or more common than infectious disease in causing calf death. While there are numerous potential causes of stillbirth, including genetic and nutritional problems, dystocia is the single most common predisposing cause of stillbirth.
Dystocia delivery is not only responsible for dramatically increasing the likelihood of stillbirth, but also increases the risk for subsequent calf health problems. By disturbing adaptation to extra-uterine life, dystocia impairs normal physiological functions, increases the risk of poor colostral transfer and decreases resistance to infectious pathogens, therefore increasing infectious disease likelihood.For a calf management program, the day of delivery is the single most critical time. Although dystocia cannot be eliminated, its' effects on the cow and the calf can be mitigated by proper management and decision-making. Calves from dystocia delivery, plus calves born without dystocia that are slow in adaptation, can be identified and managed to increase their survival. Colostrum management and appropriate calf biosecurity measures also need to occur in this critical first day. If optimum calf health is the goal, all of the observations, decisions and actions involved in delivery and the first day of a newborn calf's life should be performed by well trained workers who are educated about the importance of their work to the long-term health of the calf.