Relationship between Serum Total Protein and Serum IgG in Holstein Calves Fed Either a Lacteal- or Plasma-derived Colostrum Replacer

Abstract

Bovine neonates have a naïve immune system and must initially rely on the absorption and passive transfer of maternally derived immunoglobulins (lg) ingested in colostrum. Acceptable passive transfer (APT) is defined as a serum IgG≥10 mg/mL between 24-48 hours of age. A serum total protein (STP) cutpoint of 5.0 or 5.2 g/dl is commonly used to predict APT for calves fed lacteal-derived whole colostrum (Calloway et al, 2002). However, many producers now feed powdered commercial colostrum replacers (CR). Some CR products contain lacteal-derived (LD) lg while others contain lg derived from spray-dried plasma (PD). Research is needed to determine the best STP cutpoint to predict APT for calves fed either LD or PD CR products. The objectives of this study were to 1) describe levels of passive transfer and 2) determine the relationship between STP and IgG for neonatal calves fed a commercially available LD CR or PD CR product, respectively.