Livestock Growth, Development, and Environmental Factors
Growth and Interaction with the Environment
- It increases in weight (mass increase) before it reaches maturity.
- It is produced by cell division (hyperplasia) and elongation of cells (hypertrophy) through the incorporation of material from the environment.
- Changes in shape and body composition.
Development
Is defined as the coordination of all the different processes that take place in the animal until it reaches maturity.
Livestock production is to be understood as the set of processes of both growth and development, which when combined produce an animal with good production characteristics.
Growth Curve
- Prenatal puberty market
- Rapid growth
- Home dep. fat (puberty)
- Fat (Market)
Ways to Measure Growth
- Live weight
- Daily Gain
- Number of days to reach a certain weight
- Weight adjusted
Adjusted Weight
Accumulation of Tissue
- Muscle > Fat > Bone
Factors Affecting Growth
Genetic Factors: Muscle to Bone Ratio
- Meat Animal 4.4:1
- Animal milk 3.9:1
- Double muscle > 5:1
b) Maturity
Depending on the species and race.
Relationship between size and carcass composition in beef steers.
Meat Animals Muscular Type
Selection for muscle size resulted in some interesting cases.
“In pigs, heavy muscled types are associated with low resistance to stress and the production of an undesirable type of meat (PSS – porcine stress syndrome)”
“In cattle, the emergence of a mutation in the myostatin gene regulating a type resulting in muscle hypertrophy – a double muscle races.”
“In sheep, the condition also appears and is known as Callipyge.”
Dual Effect of Muscle on the Carcass Composition
In lambs, Callipyge muscle hypertrophy.
Factors Affecting Growth
- Sex
- Nutrition
Requirements of Growing Cattle as Body Weight Increases
- The consumption of dry matter increases.
- The requirements of energy increases.
- The requirements for protein diminishes.
- The requirements of calcium and phosphorus decreases.
How Does the Environment Affect Animal Production?
With intensive management, integrated companies such as poultry, swine confinement operations, and large dairies, many environmental conditions are sufficiently controlled.
With extensive management, there is less control over environmental conditions.
Environmental influences on livestock: Temperature, sunlight, moisture, nutrition, diseases, pests, soils, altitude, wind, predators.
Effect of Environmental Conditions on Livestock
- Messages that originate from the environmental conditions are known as stimuli.
- The stimuli may be physical, chemical, or biological climate.
- The interaction of this environment with the genotype determines animal performance.
Environmental Stimuli
Any environmental change that encourages adjustments in the bodily functions of physiological, metabolic, or behavior is considered as STRESS.
An unnatural and prolonged stress can become a right hand. In a situation of skilled individuals can suffer irreversible changes that are reflected in reproductive problems, diseases, and/or death.
Ways of Coping with Environmental Factors
- Acclimation: Temporary adjustments to environmental changes are generally mild and reversible.
- Adaptation Involves more time, natural selection, and transfer of environment-friendly traits to offspring.
Temperature
Animals can be classified into two major groups: Homeotherms and Poikilotherms.
Adjustments in Response to Temperature Changes
As the seasons change, two important environmental changes occur in temperature and day length.
There are hormonal controls that help the animal to respond to these changes: Destination of energy and hair growth or thickening of the skin.
Characteristics of the Thermoneutral Zone
- It is a temperature range that the animal does not need to use extra energy to conserve or dissipate heat.
- They are not stressed by heat or cold.
- The range depends on the species, age, and production status.
- Heat production and loss are important in designing environments for animals.
- Thermoneutral zone: Cattle 5-37, 32-35 piglets at birth, sows 15-25, 0-29 Horses, Chickens 18-21
Ways of Coping with Decreasing Temperatures
You can reduce heat loss by:
- Vasoconstriction
- Increased body isolation
- Search for shelters
- Reduction of surface area
You can increase heat production:
- Increased food consumption
- Increased physical activity
- For exposure to solar radiation
Ways of Coping with Rising Temperatures
Increase heat loss by:
- Vasodilation
- Decrease in body insulation
- Increased body surface
- Increased evaporation by sweating or panting
- Avoiding sun exposure
Reduce heat production:
- Decreased consumption
- Decline in
Other Environmental Factors
- Light: Great importance in the reproductive cycles through the photoperiod.
- Ventilation: Important component in controlling the temperature and humidity of the facilities, and gas control.
- Area: Understood as the minimum area required for an animal to achieve the expected performance.
Confinement
- Provides a comfortable, stress-free environment.
- Minimizes risk of injury and disease.
- Increased efficiency of work (is it possible to automate).
- Seasonal fluctuations are reduced production.
- Protects animals from predators.
Disadvantages of Containment
- Considerable capital
- High energy demands (based on the use of electricity)
- Requires more expertise to be handled
- There may be serious problems of pollution if not handled properly
- It is very flexible
- Stress in animals
Pollution from Livestock
- Environmental: Animal facilities and activities associated with significant sources of pollutant emissions into the air, water, and soil.
- Biosphere: Contamination of plants, animals, and/or hazardous to human health and pathogens.
Animal Waste Production
(tons/year) Dairy cow 21, Beef steer 6.6, Sheep 3.6, Pigs 0.75, Horses 8.5, Broiler 0.05
Recycling Options
- Source of plant nutrients (fertilizer)
- Ingredients in animal feed
- Substrate for methane generation
- Substrate for microbial protein production and insect
Animal Waste Processing
Dehydration, Silage, Compost
Food Safety of Animal Products
Toxicity. High contents of Cu, pathogenic bacteria and parasites, drug residues