Feeding heat-treated colostrum to neonatal dairy heifers: Effects on growth characteristics and blood parameters

Abstract

Newborn Holstein heifer calves were studied to compare absorption of immunoglobulin G (IgG1 and IgG2), total serum protein concentration, lymphocyte counts, health scores, growth, and starter intake after receiving unheated or heat-treated colostrum. First-milking colostrum was collected from Holstein cows and frozen at −20°C to accumulate a large batch. After thawing and mixing, half of the colostrum was transferred into 1.89-L plastic containers and frozen at −20°C until needed for feeding. The remaining half was heated at 60°C for 30min, transferred into 1.89-L plastic containers, and then frozen at −20°C until needed for feeding. Forty heifer calves weighing ≥32kg at birth were enrolled into 1 of 2 treatment groups before suckling occurred. For the first feeding, 3.8L of colostrum was bottle fed by 1.5 to 2h of age. For the second and third feedings, pasteurized whole milk at 5% of birth body weight (BW) was fed. Subsequently, calves received milk replacer containing 20% crude protein and 20% fat at 10% of birth BW/d until wk 5. Milk replacer was reduced to 1 feeding of 5% birth BW until weaning at 6 wk of age. Blood samples and growth data were collected through wk 8. Batch heat-treatment of colostrum at 60°C for 30min lowered colostrum bacteria concentration while maintaining colostral IgG concentration and viscosity. Calves fed heat-treated colostrum had significantly greater IgG concentrations at 24h and greater apparent efficiency of IgG absorption (IgG=23.4g/L; apparent efficiency of absorption=33.2%) compared with calves fed unheated colostrum (IgG=19.6g/L; apparent efficiency of absorption=27.7%). There was no difference between treatment groups in growth measurements, calf starter intake, lymphocyte counts, or health scores.