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How to calculate EPEF in poultry?

European Poultry Efficiency Factor (EPEF) is calculated as: [Livability (%) × Body Weight (kg) × 100] / [Age in Days × FCR]. Scores above 400 indicate top commercial performance.

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Newcastle Disease Symptoms & Vaccination Guide

Veterinary Reviewed

Newcastle Disease (NDV): Clinical Pathotypes & Control

Scientific overview of Avian Paramyxovirus-1 pathology, symptoms, and vaccination schedules.

Scientific Overview

Newcastle Disease is a highly contagious viral disease affecting domestic and wild bird species globally. Caused by virulent strains of Avian Paramyxovirus-1 (APMV-1), it can manifest in viscerotropic (digestive hemorrhages) or neurotropic (nervous paralysis) pathotypes, causing up to 100% flock mortality.

Clinical Signs and Virulence Pathotypes

Strains are classified into three pathotypes based on severity: Velogenic (highly virulent, causing acute respiratory distress, torticollis/twisted necks, facial swelling, and rapid death); Mesogenic (moderate virulence, causing mild nervous signs and respiratory distress in young pullets); and Lentogenic (low virulence, subclinical respiratory infections used for live vaccine strains like Hitchner B1 and LaSota).

Visceral Lesions and Prophylaxis

Gross lesions of velogenic viscerotropic NDV include severe petechial (pinpoint) hemorrhages on the tips of the proventriculus glands, necrosis/ulceration of Peyer's patches in the intestine, and hemorrhagic cecal tonsils. Control relies on strict biosecurity to exclude vector wild birds, and live/killed vaccination schedules to establish mucosal and circulating antibodies.

school Verified Peer-Reviewed Academic Citations & Literature Standards

All scientific data, diagnostic criteria, and performance benchmarks presented on this page are derived from published peer-reviewed journals and official veterinary codes:

Avian Pathology & Diagnostics: World Organisation for Animal Health (WOAH, 2023). Manual of Diagnostic Tests and Vaccines for Terrestrial Animals. Paris, France.
Poultry Diseases & Histology: Swayne, D.E., et al. (2020). Diseases of Poultry (14th ed.). Wiley-Blackwell / American Association of Avian Pathologists.
Nutrition & Feed Chemistry: Leeson, S. & Summers, J.D. (2001). Commercial Poultry Nutrition (3rd ed.). University Books, Guelph, Ontario.
Commercial Breed Standards: Aviagen (2024). Ross 308 & Cobb 500 Broiler Performance Objectives. / Lohmann Breeders (2024). Lohmann Brown Management Guide.