Population dynamics of the parasitic stages of Oesophagostomum dentatum in pigs in single and trickle infections

age animal diseases cerdo dynamique des populations ecologia ecologie ecology edad egg production enfermedades de los animales helminthe helminths helmintos infection largura length longueur maladie des animaux mathematical models oesophagostomum dentatum ova ovule population dynamics porcin production d'oeufs swine