Chapter 10/11

• What is "ad libitum"?

  unlimited feed quanitity
• The highest producing animals will give the farmers the greatest return on his/her investment. True or False.

  FALSE
• In growth trials, what is the measure of production or productivity?

  average daily weight gain
• Which of the following would be the type of data collected in digestion trials?

  average daily gain
• Which of he following pieces of information do you need to calculate apparent digestibility?

  -amount of the nutrients in the feed

  -amounts of nutrients in feces
• Which of these digestibility indicates (internal marker) gives the most accurate results?

  acid insoluble acid
• Which of the following can serve as internsl indicators to track digestiblity?

  lignin, acid-insoluble ash, silica
• What sort of data would be collected in a balance trial?

  amount of a nutrient absorbed & retained by an animal
• Which of the following would be characteristics of a negative energy balance?

  -the animal is losing weight

  -the animal is losing more energy than its consuming
• Total energy releases by complete combustion of a foodstuff:

  gross energy
• Total digestible nutrients (TDN)) can be approximated by:

  gross energy
• Which measure of energy is the most accurate in terms of nutrients/energy available to the animal?

  Net energy
• In birds, fecal energy & urinary energy are released through the same route. Which energy measures cannot be used for birds?

  Digestible energy
• How is heat increment measured?

  Calorimetry
• How would you measure or determine heat increment for an animal?

  direct calorimetry
• Which of the following is most closely completed with heat increment or heat production?

  metabolic body weight
• Which of the following energy required processes are part of basal metabolism?

  • energy to maintain electrochemical gradients
  • energy to maintain resting muscle tone
  • energy required for circulatory processes
  • energy required for respiration and secretion
• Heat increment is most closely related to:

  body surface area
• What factors affect nutrient utilization in livestock?

  • Animal species
  • Age
  • Physiological state
  • Type of GI tract
  • Level of consumption
  • the source of the nutrients
  • Physical form of nutrient (pelleted, ground, etc)
  • Health of animal (eg. Parasitic or other infection)
• How do growth trials measure nutrient utilization?

  Test diet versus standard diet:

  • fed ad libitum
  • paired feeding
  • electronic feeding devices

  (standrad-control vs test diet-Variable)
• How do digestibility trials measure nutrient utilization?

  
  

  
  

  use of indigestible substances as a indicator/marker

  • internal & external indicators

  (nontoxic, easily analyzed & indigestible)
• How do balance trials measure nutrient utilization?

  Provide information about utilization of nutrients that are absorbed

  
  

  measures total amount of a nutrient consumed/absorbed and total amount of a nutrient excreted and use an equation to measure the resultant value.

  (In a this trial, individual intake is measured similar to the first method in a digestion trial.)
• How do feeding trials measure nutrient utilization?

  measuring efficiency of production

  • milk volume
  • weight gain of offspring
  • laying efficiency in chickens
• List Pros: Balance Trials

  • help in formulating balanced diets tailored to specific nutritional needs.'
  • provide precise measurements of nutrient intake and utilization
  • directly assess how much of a nutrient the animal consumes and how much is retained or excreted.
• List Cons: Balance Trials

  • trials can be time-consuming due to the need for precise measurements and monitoring
  • require specialized facilities and equipment, making them costly to conduct.
  • intensive labor for collecting and analyzing
  • may only be applicable to the specific conditions
• List Pros: Growth Trials

  • Large amounts of data
  • Reasonable costs
  • Animals can be maintained under normal environmental conditions/situations
  • Measurements are easily obtained
  • Results reflect fundamental biological response
• List Cons: Growth Trials

  • growth is a variable biological parameter
  • Accurate individual weights**

  (Fill- varies from animal to animal

  Ruminants– GI tract accounts for a significant portion of weight)

  • Body composition is a more accurate indicator of growth
• List Pros: Digestibility Trials

  • directly measure the digestibility of nutrients by analyzing the intake and excretion of food components.
  • accurate insights into how well animals can break down and absorb nutrients from their diet.
  • help identify the nutritional quality of different feed ingredients and diets for animals.
• List Cons: Digestibility Trials

  • resource-intensive,
  • often require an extended period
  • primarily focus on the digestibility of nutrients and may not provide comprehensive insights into other aspects of animal nutrition, such as feed intake or growth performance.
• List Pros: Feeding Trials

  • better assessment of bioavailibility
  • Maintain animals under as close as possible to "real/actual conditions".
  • The results can be applied directly to commercial production systems.
• List Cons: Feeding Trials

  • more expensive, time consuming, & challenging to isolate specific nutrients due to complex diet/ interaction of nutrients.
  • Difficulty for correcting confounding factors**

  
  

  *a factor other than the one being studied that is associated both with the disease (dependent variable) and with the factor being studied (independent variable).*
• define growth trials

  nutrients equipment for growth change with stage of growth

  • are experiments where scientists study how animals grow over time
  • test diet versus standard diet
  • all animals at similar stages of growth
• define balance trials

  Provide information about utilization of nutrients that are absorbed

  • positive balance: more is absorbed than excreted
  • negative balance: more is lost than absorbed

  **source of nutrients would be dietary**
• define feeding trials

  measuring efficiency of production

  -are experiments where scientists study how animals grow over time,
• define digestibility trials

  proportion of nutrients absorbed from GI tract

  --pretest period of 3-10 days to make sure GI tract is cleared of previous diet

  --collect feces
• What internal and external indicators are used in digestibility trials?

  Internal: Lignin, Silicon, Acid insoluble ash

  
  

  External: chronic oxide, rare earth elements, nontoxic dyes
• define feed efficiency

  estimate of nutritional adequacy of diet or feedstuff

  
  

  the rapidly growing animal uses less feed for maintenance, and more is available for growth/gain
• Define: TDN

  expressed as weight or percent of fed that is digested
• Define: Associative effect

  combining different types of feed ingredients in a diet can enhance overall nutrient

  (may differ than when a single feedstuff is fed alone)
• Define: Bioavailability

  the extent a substance or drug becomes completely available to its intended biological destination(s).

  (The ability of a drug or othersubstanceto be absorbed and used by the body.)