Absorption of Protein and IgG in Calves Fed a Colostrum Supplement or Replacer

Abstract

Newborn Holstein bull calves (n = 32) were assigned to receive a colostrum supplement (CS) containing defibrinated bovine plasma or a colostrum replacer (CR) containing an immunoglobulin concentrate obtained by concentrating the immunoglobulin (Ig)G fraction of bovine plasma. The CS and CR contained 11.1 and 21.2% of dry matter as IgG, respectively. Each animal was fed two 454-g feedings at 1 and 8h of age. The two feedings of CS and CR provided 95 and 187g of IgG, respectively. Mean plasma IgG at 24h of age was 8.0 and 13.6g/L in calves fed CS and CR, respectively, indicating acceptable absorption of Ig from both sources. Mean apparent efficiency of IgG absorption in calves fed CS and CR were 33 and 30%, respectively, and did not differ between treatments. Mean plasma total protein at 24h in calves fed CS and CR were 4.99 and 4.98 g/dl and did not differ between treatments. Increased plasma protein concentration from 0 to 24h (4.5g/L) was lower than the mean increase in plasma IgG concentration during the same period (10.3g/L), indicating altered protein profile in the blood during the first 24h of life. Correlation between plasma IgG and total protein at 24h of age was significant within treatment, but the relationship between IgG and protein in plasma at 24h varied between treatments. Predicted plasma total protein concentrations at 10g of IgG/L of plasma at 24h were 5.4 and 4.2 g/dl, in calves fed CS and CR, respectively. Prediction of plasma IgG concentration using total plasma protein may be inappropriate when calves are fed CS or CR.