PP31 Environmental Effects on Growth

1
PP31Environmental Effects on Growth

• ANS 3043
• University of Florida
• Dr. Michael J. Fields

2
Environmental Effects

• Factors associated with physical environment
• Nutrition avaliability, quantity, quality,
  location
• Living space confinement vs. extensive
• Climate temperature, humidity, precipitation,
  wind
• Geography mountains, woodlands, rolling plains,
  swamps and (or) other water types
• Photoperiod can influence feeding and
  reproductive behaviors

3
Environmental Effects

• Ambient temperature temperature of the
  surrounding environment
• Thermal neutral zone (TNZ)
• Temperature range where rate and efficiency of
  performance are maximized
• Critical temperatures of TNZ
• Lower (cold) and upper (heat) limits of the TNZ

4
Effect of temperature on feed intake, maintenance
requirements and gain
5
Ambient Temperature

• Factors That Modify Ambient Temperature
• Humidity
• Increased humidity decreases evaporative cooling
• Decreased humidity increases evaporative cooling
• Wind speed creates wind chill
• Carries heat and moisture away from the body
• Precipitation
• Increased moisture can result in increased heat
  loss from body

6
Wind chill effects on cattle with a winter coat
7
Management Effects

• Housing requirements relative to space and design
• Relationship with the physical and social
  requirements of animals
• Purpose of animals
• Work and/or pleasure
• Food, fiber and/or wool production

8
Management Effects

• Animal Management Interactions
• Physical Environment
• Confinement vs. Extensive
• Availability, quality and location of nutrition
• Ventilation and airflow
• Animal density and movement
• Protection from the elements
• Shade during summer
• Housing and/or shelter during cold weather

9
Management Effects

• Housing Surfaces
• Contact with hard surfaces causes heat to be
  dissipated away from the body
• Prevent by providing bedding (straw, shavings)

10
Management Effects

• Temperature
• Dependent on stage of production of animal and
  species
• Pigs increased temperature decreases feed
  intake and increases water intake
• Horses provide adequate shade with good air
  movement
• Allows for dissipation of heat without major
  effects on production
• Bos indicus are more heat tolerant than Bos
  taurus
• Both breeds have similar numbers of sweat glands,
  but the sweat glands of the Bos indicus are more
  functional at higher temperatures
• Bos indicus also have decreased hide thickness
  and looser fitting hide

11
Effective temperatures for swine at different
production stages an upper and lower intervention
temperatures
12

• Effects of evaporative heat loss

• Sweat glands
• Number set at birth, but activity increases with
  age
• Horses cattle sheep dogs cats pigs
• Genotype
• Bos indicus are more heat tolerant than Bos taurus

13
Management Effects

• Social Environment
• Social thermoregulation
• Living in groups vs. singles
• Preventative measures
• Vaccination sreduce opportunities for sickness
• Build immunity before animals are exposed to
  foreign antigens
• Performance dramatically reduced if
  non-vaccinated animals get sick

14
Adaptation

• Panting
• Movement of air across moist surfaces to cool
• Dogs are most effective at this (cattle are also
  effective at it)
• Physical Morphology of Animal
• Body conformation
• Increased hair coat in cold climates vs. short
  hair in warm climates
• Size of extremities (i.e. ears)
• Desert rabbit vs. Arctic hare
• Elephants vs. Musk Oxen

15
Adaptation

• Animal Insulation
• Fat cover vs. no fat cover in cold climates
• External covering on skin (hair vs. fur)
• Fur cold adapted animals
• Hair type and thickness are dependent on
  climate
• Short in warm
• Long in cold

16
Estimated lower critical temperatures in beef
cattle with differing coat characteristics
17
(No Transcript)
18
(No Transcript)
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
Adaptation

• Social dominance
• Teat order in suckling piglets
• Dertermined at birth, continue to nurse same teat
  throughout lactation
• Some teats milk better than others (pigs will
  grow differently)
• Nutrition
• Dominant animals can keep subordinates from food
• May also apply to large vs. small animals in same
  feeding area
• Group fed vs. individual feeding

23
Adaptation

• Immuno-competence
• Poor transfer of colostrum
• Results in decreased disease resistance during
  neonatal and postnatal growth
• Disease and parasite resistance
• Resistance differences within species
• Infections or injuries
• Significant negative effect on animal growth and
  performance