Animal Science & Technology — Strand 9: Energy (Teaching Notes)

Energy

The capacity to do work or cause change in animal production.

Chemical energy

The energy stored in feed molecules, which is used by animals through digestion and metabolism.

ATP

Adenosine triphosphate, the cell's spendable energy currency.

Maintenance energy

The energy required to keep an animal alive and stable.

Production energy

The energy available for growth, lactation, and reproduction after maintenance needs are met.

Gross energy (GE)

The total energy released when food is completely burnt.

Digestible energy (DE)

The portion of gross energy that is not lost in feces.

Metabolizable energy (ME)

Energy available to the animal after subtracting urine and gaseous losses from digestible energy.

Net energy (NE)

The energy available for useful purposes after subtracting heat increment from metabolizable energy.

Fecal energy loss (FE)

Energy excreted in feces, representing undigested energy.

Urinary energy loss (UE)

Energy lost in urine, especially from protein metabolism.

Gaseous product of digestion (GPD)

Primarily methane lost during digestion in ruminants.

Heat increment (HI)

Heat produced during digestion, fermentation, absorption, and metabolism.

Production potential

The maximum output of productivity an animal can achieve under optimal conditions.

Rumen acidosis

A digestive upset in ruminants caused by overconsumption of quickly fermentable carbohydrates.

Carbohydrates

Macronutrients that provide energy through storage forms like starch and sugars.

Fats

Highly energy-dense macronutrients that provide energy without increasing dietary bulk.

Proteins

Macronutrients essential for building tissues but inefficient as an energy source.

Monogastrics

Animals with a single-chambered stomach, such as pigs and poultry, that digest carbohydrates efficiently.

Ruminants

Animals with a four-chambered stomach, like cows, that heavily depend on microbial fermentation.

Digestibility

The extent to which nutrients in food can be broken down and absorbed.

Fiber

A structural carbohydrate that can be digested by some animals, but not efficiently by all.

Total Digestible Nutrients (TDN)

An older metric estimating the digestible portion of a feed's nutrients.

Dry matter intake (DMI)

The amount of feed consumed by an animal, expressed in dry matter.

Body Condition Score (BCS)

A scoring system that assesses fat reserves and overall body condition of an animal.

Negative energy balance

When an animal's energy expenditure exceeds energy intake, leading to weight loss.

Ketosis

A metabolic disorder resulting from excessive mobilization of fat reserves in dairy cows during early lactation.

Rumen fermentation

The process by which microbes break down carbohydrates in the rumen, producing volatile fatty acids.

Technical feeding

Using precision feeding and monitoring technologies to better match energy supplies to animal needs.

Energy partitioning system

A systematic approach to track how energy from feed is allocated to maintenance and production.

Energy efficiency

The ratio of output (like growth or milk) achieved for each unit of feed or energy consumed.

Feeding management

The strategies used to optimize animal feeding practices for better overall health and productivity.

Thermoregulation

The process of maintaining an optimal body temperature, which can influence energy requirements.

Metabolic body weight

A scaling idea where energy needs are proportioned to the body weight raised to the 0.75 power.

Effective fiber

The fiber necessary for ruminant health that aids in proper fermentation and digestion.

Energy balance

The comparison between energy intakes versus energy expenditures.

Critical nutrients

Other nutrients such as vitamins and minerals that are essential in energy metabolism.

Heat stress

Increased energy needs for thermoregulation, often leading to reduced feed intake.

Comparative slaughter

A research method used to measure body energy changes by analyzing body composition.

Nutrient absorption

The process by which digested nutrients pass through the intestinal lining into the bloodstream.

Methane emissions

Greenhouse gases produced by ruminant digestion, representing an energy loss.

Production disorders

Health issues in animals relating to inadequate energy or nutrient supply.

Carbon footprint

The total greenhouse gas emissions associated with a product's lifecycle, including agriculture.