Factors Affecting Animal Health

Advanced Animal Sciencec (10) (A)

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

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.

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.

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?

Physical Factors• Cannot be controlled in a field, but controllable

inside an animal facility (barn, laboratory).• Examples:– Temperature– Relative Humidity – Ventilation– Lighting– Noise

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

AnimalsTemperature °C Temperature °F

Average Range Average RangeDairy Cow 38.6 38.0 - 39.3 101.48 100.4 - 102.74Beef Cow 38.3 36.7 - 39.1 100.94 98.06 - 102.38

Pig 39.2 38.7- 39.8 102.56 101.66 - 103.64Sheep 39.1 38.3 - 39.9 102.38 100.94 -103.82Goat   38.7 - 40.7 101.66 - 105.26Horse 37.9 37.2- 38.2 100.22 98.96 - 100.76

Chicken 41.7 40.6 - 43.0 107.06 105.08 - 109.4Human 37   98.6

Source: Food and Agriculture Organization of the United Nations

Physical Factors: Humidity • 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.

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.

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

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.

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.

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.

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

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.