DFA12 and DFA36 at < 0.05. high IgG concentration. Sixty-six healthy new-born Holstein calves were randomly assigned to three treatments consisting of no supplementation (control), supplementation of 12 g/d (DFA12), or 36 g/d (DFA36) of DFAIII during the first 7 d of life via colostrum and milk replacer (MR). Calves were separated from dams at birth and bottle-fed colostrum in two meals, each targeting 2.5 L within the first 18 h of birth. Colostrum had been previously collected from other dams (and preserved frozen) within the first 2 h of calving and had a Brix value 32%. Daily consumption of starter concentrate and MR (and colostrum on the first day) were individually monitored. Calves were body Daptomycin weighed using an electronic scale at birth and on a weekly basis thereafter until the end of study at 42 d of age. A sample of colostrum fed to each calf and a blood sample from the jugular vein of the calves were collected at 12 and 24 h of life to determine the IgG concentration. The mean colostrum IgG concentration fed in the current study was 110 33.7 g/L (mean SD). No differences in animal performance were found among the treatments. Calves on all treatments consumed the same amount of colostrum with a Daptomycin similar concentration of IgG, and thus the amount of IgG consumed was also similar. Serum IgG concentrations were greater at 24 than at 12 h but did not differ among treatments. However, the apparent efficiency of absorption of colostral immunoglobulins was greater in DFA12 and DFA36 at 12 h of life than in control calves, with no differences observed at 24 h. Even when feeding high-quality colostrum, in terms of IgG concentration, supplementation with difructose anhydride III may pose an additional advantage in promoting the passive transfer of immunoglobulins in neonatal Holstein calves during the first 12 h of life. Keywords: antibodies, immunity, growth 1. Introduction Calves are born depleted of serum antibodies and IL3RA they depend on the consumption of colostrum to build some initial degree of passive immunity. Failure passive transfer of immunoglobulins is a relatively common problem in dairy production with a prevalence around 20C25% in different parts of the world [1,2,3]. The consequences of an inadequate passive transfer of immunoglobulins are impaired health and increased mortality [4]. Several studies have evaluated the possibility of improving the passive transfer of immunoglobulins in calves through colostrum management [5], time of feeding relative to birth [6], feeding amounts [7,8], feeding frequency [9], and feeding methods [10,11,12]. Some studies have also attempted to use some additives to foster antibody absorption. For example, ref. [13] reported an increased rate of IgG absorption when supplementing colostrum with mannan-oligosaccharides. Kamada et al. [14] found increases in IgG absorption when supplementing colostrum with selenium and Morrill et al. [15] reported improvements in IgG absorption when colostrum was supplemented with sodium bicarbonate. The intestine of a neonatal calf has no Daptomycin selective absorption capacity for large proteins [16], and molecules of different molecular weight are absorbed more or less at the same rate [17,18], with small differences among the Daptomycin different types of immunoglobulins. Transport of IgG through micropinocytic transfer was demonstrated using electromicroscopy [19]. Previous studies have described that a crystal disaccharide obtained from inulin of chicory root formed by two fructoses and called difructose anhydride III (DFAIII) is able to loosen intestinal tight junctions by changing the distribution of actin filaments and claudin-1 [20], resulting in a reduction in transepithelial electrical resistance [21]. Three previous studies [22,23] reported different degrees of improvements in serum IgG concentrations in calves supplemented with DFAIII, and suggested that the absorption of IgG by endocytosis as well as a nonselective concentration gradient process of the paracellular pathway of the intestinal epithelium could be enhanced by DFA III. The three Daptomycin former studies evaluated the effect of DFAIII on the colostral IgG absorption of calves fed two meals of 2 L of colostrum within the.