Disease Predisposing Factors

Overzicht

Two poultry farms near Oyo keep the same breed of bird, buy feed from the same market and sit less than a kilometre apart. When Newcastle disease reaches the area, one farm loses a third of its flock and the other loses almost nothing. The birds are not different, and the pathogen is not different. What is different is everything that made one flock's defences weaker and one flock's exposure higher long before the virus ever arrived. Those conditions are called disease predisposing factors, and they explain more about who falls sick on a farm than the pathogen itself ever does.

In this lesson you will learn what a predisposing factor is and how it differs from the actual cause of a disease, then work through six factors examiners return to every year: nutrition, housing, stress, hygiene, genetics and age, and the absence of vaccination or parasite control. For each one you will learn not just its name but the mechanism, exactly how it tips an animal toward disease, and the practical steps a farmer takes to close that door.

Doelstellingen

  1. Define disease predisposing factors
  2. State the factors that predispose farm animals to disease
  3. Explain how poor nutrition predisposes animals to disease
  4. Explain how poor housing and management predispose animals to disease
  5. Suggest ways of reducing disease predisposing factors on a farm

Lesnotitie

A pathogen is often already present on a farm without causing an outbreak. Disease breaks out when something tips the balance in its favour: a weakened animal, heavier exposure, or both. Disease predisposing factors are those tipping conditions, and a farmer who can name and remove them prevents disease before it starts.

Lesevaluatie

Gefeliciteerd met het voltooien van de les op Disease Predisposing Factors. Nu je de sleutelconcepten en ideeën, het is tijd om uw kennis op de proef te stellen. Deze sectie biedt een verscheidenheid aan oefeningen vragen die bedoeld zijn om uw begrip te vergroten en u te helpen uw begrip van de stof te peilen.

Je zult een mix van vraagtypen tegenkomen, waaronder meerkeuzevragen, korte antwoordvragen en essayvragen. Elke vraag is zorgvuldig samengesteld om verschillende aspecten van je kennis en kritisch denkvermogen te beoordelen.

Gebruik dit evaluatiegedeelte als een kans om je begrip van het onderwerp te versterken en om gebieden te identificeren waar je mogelijk extra studie nodig hebt. Laat je niet ontmoedigen door eventuele uitdagingen die je tegenkomt; beschouw ze in plaats daarvan als kansen voor groei en verbetering.

  1. Which of the following is a disease predisposing factor rather than the actual cause of disease? A. A bacterium B. A virus C. An overcrowded, poorly ventilated house D. A parasitic worm Answer: C
  2. Sustained stress increases an animal's susceptibility to disease mainly by: A. Increasing its appetite B. Raising a hormone level that suppresses immune function C. Improving its body temperature regulation D. Strengthening its skin Answer: B
  3. Day old chicks are more susceptible to disease than adult birds chiefly because: A. They eat more feed B. Their immune system is not yet fully developed C. They have thicker feathers D. They are kept in larger numbers Answer: B
  4. Which management practice would most directly reduce disease spread caused by poor hygiene? A. Reducing stocking density only B. Regular cleaning and disinfection of drinking troughs and pens C. Feeding a higher energy ration D. Selecting a hardier breed Answer: B
  5. An unvaccinated flock is at greater risk from a disease outbreak chiefly because: A. It has no trained immunity against that specific pathogen B. It eats more feed than a vaccinated flock C. It grows faster than a vaccinated flock D. Vaccination has no effect on immunity Answer: A

Aanbevolen Boeken

Introduction to Animal Science: Global, Biological, Social and Industry Perspectives
Introduction to Animal Science: Global, Biological, Social and Industry Perspectives
Ondertitel: Sixth edition
Uitgever: Pearson
Jaar: 2017
ISBN: 978-0-13-443605-0
Beschrijving: A comprehensive introduction to animal science covering anatomy and physiology, nutrition, genetics, reproduction, animal health and the major farm animal species and their production systems.
Small-scale Poultry Production: Technical Guide
Small-scale Poultry Production: Technical Guide
Uitgever: Food and Agriculture Organization of the United Nations
Jaar: 2004
ISBN: 978-92-5-105082-8
Beschrijving: An FAO Animal Production and Health Paper written by a Nigerian animal scientist, covering breeds, housing, feeding, incubation, disease control and marketing for small-scale poultry keepers in developing countries.
Tropical Animal Feeding: A Manual for Research Workers
Tropical Animal Feeding: A Manual for Research Workers
Uitgever: Food and Agriculture Organization of the United Nations
Jaar: 1995
ISBN: 978-92-5-103758-4
Beschrijving: An FAO Animal Production and Health Paper on the principles of ruminant and non-ruminant nutrition and the practical use of tropical feed resources, including crop residues and by-products, in sustainable livestock systems.