1. Factors Affecting Animal Health
Advanced Animal Science
c (10) (A)

2. Objectives You will be able to:
Give examples of physical factors which affect animal health
Discuss the important of diseases as it relates to production and health
Articulate the importance of good stockmanship in the maintenance of animal health

3. Stockmanship Stockmanship is the skill of managing livestock.
Part of managing livestock is ensuring their health and safety.
In order to ensure health and safety, you must understand the factors which contribute to diseases of livestock.

4. Disease Factors contribute to disease in an animal.
Disease is a major profit-limiting factor in animal production in both developed and developing countries.
Anything not “normal” is a disease.
We will discuss the factors which contribute to an animals ability to become diseased.

5. Introduction
Animals are impacted by a great number of factors which influence their health.
Some factors are controllable, some are not.
What are some examples of controllable environmental influences?
What are some examples of non-controllable influences?

6. Physical Factors
Cannot be controlled in a field, but controllable inside an animal facility (barn, laboratory).
Examples:
Temperature
Relative Humidity
Ventilation
Lighting
Noise

7. Physical Factors: Temperature
Animals can tolerate extreme temperatures, but will impact health and productivity if exposed for an extended period of time.
Stressed animal will become more susceptible to disease.
Normal Body Temperatures of Domestic Animals & Humans
Animals
Temperature °C
Temperature °F
Average
Range
Dairy Cow
38.6
101.48
Beef Cow
38.3
100.94
Pig
39.2
102.56
Sheep
39.1
102.38
Goat
Horse
37.9
100.22
Chicken
41.7
107.06
Human 37
98.6
Source: Food and Agriculture Organization of the United Nations

8. Physical Factors: Humidity
Too low humidity
irritation of mucous membrane
Too high humidity
promote growth of fungus infections.
Poultry lack sweat glands, evaporative heat loss must come from respiratory tract.
40% to 80% relatively humidity is ideal.

9. Physical Factors: Radiation
Solar radiation affects heat load on the animal in addition affecting the unpigmented skin some breeds have.
Radiation can be reduced through the use of shaded areas.
Note: shaded areas must be large enough to not inhibit heat loss through other means.

10. Physical Factors: Air Movement
Air movement assists in heat loss through evaporation and conduction/convention.
Air temperature should be lower than skin temperature.
Air movement is necessary to supply fresh air and remove noxious air.
Wind velocity of 0.2m/s is the minimum.
Upper critical temperatures can increase minimum wind velocity to 1.0m/s

11. Physical Factors: Precipitation
Rain can penetrate the fur and decrease insulation value.
Rain and wind can result in excessive cooling during.
A naturally greasy hair coat will resist water penetration.
Shelter is the best method of preventing this problem.

12. Microbiological Environment
Animals in good condition, well fed and watered will resist disease well.
Pens, particularly those for calving and farrowing, should be constructed in easily cleaned and disinfected materials.
Avoid corners and recesses where manure and dirt can accumulate.

13. Microbiological Environment
Animal holding facilities should be cleaned and disinfected periodically.
Clean and disinfect pens before transferring animals between pens.
“All-in, all-out” policy
Empty, clean, and disinfect between batches of animals.

14. Nutrition Poor nutrition can contribute to poor health of the animal.
Examples:
Vitamin A deficiency
Colic
Quick change in diet
Milk Fever
Low blood calcium, hypocalcemia
Source: Texas AgriLife Extension Service

15. Other Environmental Factors
Acoustical factors (sound) – keep sound levels low, avoid sudden noises.
Soft radio music in a milking parlor has been shown to have a soothing effect on cows.
Dust can carry microorganisms, contributing to disease.