(F15) The Effects of Polyclonal IgY Supplementation on the Health of Pre-weaned Dairy Calves

Background: Diarrhea (DIA) is prevalent in preweaned dairy calves. Non-antimicrobial treatments, such as immunoglobulin Y (IgY), may reduce pathogen colonization and reduce the risk of antimicrobial resistance on farms. 

_____________________________________________________________________ 

Hypothesis/

Objectives: Polyclonal IgY oral supplementation is associated with reduced duration of DIA, pathogen shedding and improved average daily gain (ADG) in dairy calves. 

_____________________________________________________________________ 

Animals: 187 newborn dairy calves 

Methods: Sample size (n=80) was calculated to detect a 20% difference in days with diarrhea between groups (1-β=0.8; α=0.05). A randomized controlled clinical trial allocated calves to treatment (TX; received a single dose of IgY at birth; n=91) or control (CON; no IgY administered; n=96) groups over 4 months from 12/2023. Fecal scores (FS) and body weights were collected, and fecal pathogen shedding (Salmonella culture, and BCoV, BRV, C.parvum qPCR). Multivariable models assessed associations between treatment group, median (Q1, Q3) days with DIA (FS ≥2) during days 1-14, pathogen shedding, and ADG. 

_____________________________________________________________________ 

Results: The median number of days with DIA was 2 (1,3) for CON and 1 (1,3) for TX calves (P = 0.68). No significant differences were detected in the odds of pathogen shedding (P> 0.2): BCoV (OR: 2.43, CI: 0.7-8.88), BRV (OR:1.08, CI: 0.30-3.85).  TX was not associated with a difference in ADG (p= 0.69; 0.81 kg +- 0.05;88). 

______________________________________________________________________ 

Conclusion and clinical relevance: Polyclonal IgY supplementation at birth was not associated with improved clinical health, reduced pathogen shedding or increased ADG. Further studies investigating multi-day polyclonal IgY supplementation is indicated.