Effect of different heating times of high-, medium-, and low-quality colostrum on immunoglobulin G absorption in dairy calves

摘要

The objective of this study was to determine the effectof different durations of heat treatment on passivetransfer of IgG from high-, medium- and low-qualitycolostrum. Colostrum was collected from The PennsylvaniaState University dairy herd and divided byquality (high, medium, or low) based on colostrometermeasurements. Colostrum was pooled by quality to create3 unique batches. Each batch was further dividedin thirds as follows: frozen to be fed without heat treatment,heated at 60°C for 30 min, or heated at 60°Cfor 60 min. Colostrum samples from each treatmentwere collected and analyzed for standard plate count,gram-negative noncoliforms, coliforms, and total IgGconcentration. Serum samples were collected from 108Holstein calves before feeding colostrum and 24 h afterbirth. Blood samples were analyzed for total protein,total IgG, and hematocrit. Colostrum quality (high,medium, or low), heat treatment (unheated, 60°C for30 min or, 60°C for 60 min), and their interactionwere analyzed as fixed effects, with calf sex includedas a random block effect. Colostrum IgG was differentbetween quality groups (92.5, 59.4, and 48.1 mg/mLof IgG). Heating colostrum reduced IgG concentrationcompared with the control by 9% when heated for 30min and by 12% when heated for 60 min. Colostrumheated for 60 min had a lower standard plate countthan colostrum heated for 30 min or not heated (1.8,2.0, and 3.6 log cfu/mL, respectively). Serum IgGconcentration at 24 h increased as colostrum qualityincreased (18.0, 22.2, and 24.8 mg/mL) and tended toincrease as heat treatment time increased (19.7, 20.3,and 25.0 mg/mL of IgG). Apparent efficiency of IgGabsorption was greater in calves that received mediumqualitycolostrum compared with calves fed high-qualitycolostrum (38.1 and 25.0%, respectively). These resultssuggest an upper limit may exist to the amount of IgGabsorption in a given time period and that medium- orhigh-quality colostrum yields similar blood IgG concentrationgiven the same volume of intake.