PSI-10 Comparative evaluation of colostrum substitutes on lamb passive immunoglobulin transfer, and adaptive immune development.

Abstract We investigated if different colostrum sources resulted in different passive immunoglobulin transfer and adaptive immune system development in lambs. Newborn Polypay lambs were randomly assigned to 4 treatment groups: Fresh ewe colostrum (FrC; n=10), Frozen ewe colostrum (FZ; n=11), Frozen cattle colostrum (CC; n=11), or Artificial cattle colostrum (AC; n=11). Lambs received colostrum (65 ml/kg of bodyweight) within 4h post-parturition and were reared on ad libitum milk replacer, creep feed, and alfalfa hay. Lambs were weaned from milk replacer at 4 weeks of age (W), then were immunized and boosted with ovalbumin (1mg/kg) at 5W and 9W, respectively. Serum was extracted from blood samples that were collected at birth, 24h and then weekly until 13W. Ovine and Bovine IgG were quantified through species specific radial immunodiffusion, while ovalbumin-specific antibodies were quantified through indirect ELISA. The study was analyzed as a completely randomized design with repeated measures (PROC MIXED - SAS). IgG data were analyzed as total and relative (serum IgG/colostral IgG) concentrations. There was no significant (P ≥ 0.18) treatment-by-time interaction or main effect of treatment in total or relative IgG concentrations for FrC vs FZ. However, there was a tendency (P = 0.06) for a main effect of treatment in relative IgG with FrC tending (P = 0.07) to be greater at 1W and being greater (P ≤ 0.03) at 2W (19.70 vs. 10.45 ± 2.89%), 3W (19.39 vs. 7.97 ± 2.99%), and 4W (18.05 vs. 8.4 ± 2.89%). There was a significant (P = 0.02) treatment-by-time interaction for IgG concentration between CC vs AC with CC being greater (P ≤ 0.01) at 24h (2441.19 vs. 1616.28 ± 198.43 mg/dL), 1W (1351.96 vs. 663.48 ± 121.2 mg/dL), 2W (864.23 vs. 391.05 ± 93.23 mg/dL), and 3W (551.76 vs. 225.93 ± 53.46 mg/dL). There was a significant (P ≤ 0.01) treatment-by-time interaction in relative IgG for CC vs AC, with CC being greater (P ≤ 0.03) at 24h (18.08 vs. 16.19 ± 0.61%), 1W (9.89 vs. 6.50 ± 0.61%), 2W (6.29 vs. 2.08 ± 0.64%), and 3W (4.03 vs. 2.08 ± 0.66%). The FrC lambs showed a faster (P = 0.01) humoral response than CC lambs beginning 1 week post immunization (WPI). Moreover, FrC and AC had a more robust humoral response against ovalbumin, with antibody levels being over 175% greater at 3, 4 and 8 WPI (P ≤ 0.03) and 2,5,6,7 WPI (P = 0.07). Additionally, FrC lambs tended (P = 0.08) to show increased antibody concentrations at 3 and 4 WPI in comparison to FZ lambs. These results suggest that fresh colostrum provides superior passive immune protection and promotes adaptive immune development better than other colostrum sources.