24‐Hour postnatal total serum protein concentration affects the health and growth performance of female Holstein dairy calves

BACKGROUND: Total serum protein (TSP) within the first few days of life in the neonatal calf has predictive value for subsequent growth and production in calves before and after weaning. INTRODUCTION: The objective of this study was to evaluate the effect of TSP concentration 24‐h after birth (24‐h) on the performance and health of Holstein dairy calves. METHODS: A total of 152 female calves were enrolled in this study. Blood samples were collected at 24‐h, and TSP concentration was measured with a refractometer. Calves based on TSP concentration at 24‐h were allocated into three groups: 1 – TSP ≤6.5 g/dL, 2 – TSP between 6.6 and 6.9 g/dL and 3 – TSP ≥7 g/dL. The weighing was done at birth and at days 30 and 60. Starter feed intake was recorded from day 3 to weaning, and body structures were measured at birth and weaning day. RESULTS: Calves with TSP >6.5 g/dL had greater body weight at days 30 and 60 than calves with TSP ≤6.5 g/dL. Average daily gain during 1–30 and 1–60 days of life increased as TSP increased. Furthermore, starter feed intake during the first 60 days of life was greater in calves with TSP ≥7 g/dL than calves with TSP <7 g/dL. The TSP concentration influenced structural growth, and >6.5 g/dL calves had greater heart girth, hip width and body length than ≤6.5 g/dL calves. Moreover, odds ratio for pneumonia decreased as TSP increased, whereas diarrhoea was unaffected. CONCLUSION: The TSP at 24‐h is an important contributing factor for the variation in growth performance and health of preweaning calves, and strategies to improve calf immunity and increase TSP lead to better animal health during preweaning period. IMPLICATIONS: These results indicated that TSP ≥6.5 g/dL possibly was associated with greater performance, and this concentration could be considered a baseline for future analyses.