Submitted to: Journal of the American Veterinary Medical Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/12/2005
Publication Date: 3/15/2006
Citation: Dewell, R.D., Hungerford, L.L., Keen, J.E., Laegreid, W.W., Griffin, D.D., Rupp, G.P., Grotelueschen, D.M. 2006. Association of neonatal serum immunoglobulin G1 concentration with health and performance in beef calves. Journal of the American Veterinary Medical Association. 228(6):914-921.
Interpretive Summary: Background - Newborn calves acquire infection-risk reducing antibodies from their dams via ingestion and absorption of colostrum (the first milk) in the first 24 hours of life. This process is known as "passive transfer." Failure of passive transfer, where inadequate levels of maternal antibodies are transferred to the calf, is a common cause of sickness and death in calves. The precise level of maternal antibody that protects calves is not known. Objectives - In this study, the association between serum immunoglobulin G1 (IgG1) concentration (a quantitative measure of the success of passive transfer) in 1,568 Nebraska newborn beef calves (born over three years in the same herd) and their subsequent pre- and postweaning sickness, death, and average daily gains was investigated. Results - Lower IgG1 levels were significantly associated with higher sickness, death losses, and lower weight gain in the preweaning period. New thresholds were identified for optimal IgG1 transfer. Calves with serum IgG1 lower than 2,400 mg/dL were 1.6 times more likely to get sick before weaning and 2.7 times more likely to die before weaning than calves with higher IgG1 levels. Calves with serum IgG1 levels of at least 2,700 mg/dL weighed an estimated 7.38 lb (3.35 kg) more at 205 days of age than calves with lower IgG1. No significant associations of serum IgG1 with feedlot (postweaning) morbidity, mortality, or average daily gains were identified in this study. Conclusions and Clinical Relevance - This study defined a much higher threshold of IgG1 for optimal health and performance of calves than many other studies have reported. Implementation and maintenance of management and intervention strategies by veterinarians and producers designed for early detection and treatment of calves at risk for failure of passive transfer is likely to result in increased preweaning health and growth.
Technical Abstract: Objective--To evaluate associations between neonatal serum IgG1 concentration and pre- and postweaning morbidity and mortality rates and average daily gains (ADGs) in beef calves and define a cutoff point for serum IgG1 concentration necessary for optimal health and performance of beef calves. Design--Nonconcurrent cohort study. Animals--1,568 crossbred beef calves. Procedure--Single radial immunodiffusion was used to quantitate IgG1 concentration in sera collected from calves between 24 and 72 hours after birth. Logistic regression, ANCOVA, and likelihood ratios were used to analyze data. Results--In the preweaning period, lower perinatal IgG1 concentrations were significantly associated with higher morbidity rates, higher mortality rates, and lower ADGs. Calves with serum IgG1 concentration <2,400 mg/dL were 1.6 times as likely to become ill before weaning and 2.7 times as likely to die before weaning as calves with higher serum IgG1 concentrations. Calves with serum IgG1 concentration of a least 2,700 mg/dL weighed an estimated 3.35 kg (7.38 lb) more at 205 days of age than calves with lower serum IgG1 concentration. No significant association of serum IgG1 concentration with feedlot morbidity, death, or ADG was identified. Conclusions and Clinical Relevance--By use of likelihood ratios, the threshold of serum IgG1 concentration for optimal health and performance of calves was higher than values reported previously. Implementation and maintenance of management and intervention strategies designed for early detection and treatment of calves at risk for failure of passive transfer will likely result in increases in preweaning health and performance parameters.