Serum Total Protein Concentration as a Protective Factor against Pneumonia in Calves

Bovine Respiratory Disease (BRD) is one of the most significant health and economic challenges during the pre-weaning period, contributing substantially to calf mortality, reduced growth, and impaired future performance. Calves are born without maternal immunoglobulins due to the epitheliochorial structure of the bovine placenta, making passive immune transfer via colostrum essential for early protection. Serum Total Protein (STP) concentration is widely used as a simple and cost-effective indicator to assess the success of passive immune transfer. This study aimed to investigate the association between STP and the incidence of pneumonia in pre-weaning Holstein calves. The study was conducted on ۱۸۳ calves under ۱۵ days of age on a dairy farm in Alborz province from August to October ۲۰۲۴. Blood samples were collected at ۴۸ hours of age, and STP was measured using a handheld optical refractometer. Respiratory symptoms were monitored, and data were analyzed using the Cox proportional hazards model. Results showed that higher STP was significantly associated with a reduced risk of pneumonia (P = ۰.۰۴۹). Each unit increase in STP corresponded to an approximately ۳۹% reduction in disease risk. These findings highlight the importance of proper colostrum management and support the use of STP as a predictive tool for identifying high-risk calves. Monitoring STP can be an effective strategy to reduce BRD incidence and improve calf health and productivity.

کلیدواژه ها:

Calf pneumonia ، Serum Total Protein ، Passive immune transfer ، Colostrum.