Viviana Parreño, National Institute of Agricultural Technology Argentine

Anabela Mira1, Marina Bok2,3 Juan Cruz Franco2, Cecilia Lang1, Alejandro Vivas2, Esteban Medina2, Diego Wenz1, Demian Bellido1-2, Andrés Wigdorovitz 2-3 & Viviana Parreño2-3 1 Vetanco S. A. Argentina. 2 Bioinnovo S.A. Argentina. 3 Incuinta-IVIT, INTA-CONICET, Argentina.

Vaccines

Group A Rotavirus (RVA) is a major pathogen associated with neonatal calf diarrhea worldwide. Vaccination of pregnant dams during late gestation is a common preventive strategy, reducing the severity of diarrhea but failing to fully control the disease, particularly in dairy farms where calves are separated from their dams at birth and fed milk replacers lacking antibodies. To enhance protection against neonatal calf diarrhea and reduce antibiotic use, an oral passive immune strategy was developed using heterologous egg yolk immunoglobulins (IgY) targeting rotavirus, coronavirus, E. coli, Salmonella, and Cryptosporidium parvum (Cp). This study evaluated the efficacy of the product in reducing RVA and Cp-associated diarrhea. Fifty newborn calves from a dairy farm in Córdoba, Argentina, with a prior diagnosis of RVA and Cp diarrhea, were randomly assigned to two groups: Control (n = 25) and IgY-treated (n = 25). The treated group received two daily doses of 20 g of spray-dried egg powder mixed with milk for 14 days. Individual fecal samples were collected from all calves for 30 days. Treated calves showed a significant reduction in diarrhea duration and severity and a significant decrease in both the duration and quantity of RVA and Cp shedding compared to the control group (Student T test, p<0.05). These results indicate that IgY powder effectively reduced RVA and C. parvum infections and clinical disease without promoting antibiotic resistance.