Lecture 21 & 22 Flashcards
How does feed cost and net income for pork producers in Saskatchewan relate?
1 pt
They’re inversely related
Does production drive nutrition or does nutrition drive production?
1 pt
In dairy cows, early lactation, feed intake doesn’t matter. Mid to late lactation, feed intake determines milk production
Definition of hunger, preference, selection, appetite, palatability
5 pts
- Hunger - astrong need or desire for food
- Preference - what animals select given minimal physical constraints
- Selection - preference modified by environmental circumstances
- Appetite - an instinctive physical desire, especially one for food or drink
- Palatability - acceptable to the taste
Definition of satiety, orexigenic, anorexigenic, adlibitum, pica
5 pts
- Satiety - the condition of being full or gratified beyond the point of satisfaction
- Orexigenic - increasing or stimulating the appetite
- Anorexigenic - producing anorexia, an agent that diminishes or controls the appetite
- Ad libitum - ‘at one’s pleasure’ or food is available at all times
- Pica - is the persistent craving and compulsive eating of nonfood substances (lack of phosphourous or boredom)
What are examplesof farm animals not being fed ad libitum?
2 pts
- Sows in gestation are limit fed to avoid too high of back fat before and after farrowing
- Broiler breeders
What are the two main categories of feed supply?
2 pts
- Diet is supplied (pigs, chickens, dairy cows) - animal has no choice, responsibility of provider to meet the nutrient requirements
- The animal is responsible for feed (nutrient) selection (animals on range)
What are the mechanisms of feed intake control?
5 pts
- Feedback from the gastrointestinal tract
- Metabolites and hormones
- Central nervous system
- Learning about food: conditionedpreferences and aversions
- Diet selection
What are factors that would affect feed intake?
11 pts
Feed
* availability
* Quality
Environment
Animal
* Integration with the CNS
* Gastrointestinal
* Adipose tissue
* Hormones
* Metabolites
* Learning
What is feed intake control?
7 pts
Short-term
* Meal size
* Frequency of meals
Long-term
* Homeostasis
* Homeorhesis
* Maintenance of body weight and adiposity
How to measure food intake?
2 pt
- Simplest - measure feed before and after eating
- Marker dilution - intake determined from ratio between marker in the feed and the feces (must know feed digestibility)
What is eating behaviour and feed availability like in swine?
6 pts
- Grow finish pigs typical consume 10 to 20 meals per day
- smaller pigs eat more meals
- increasing the number of pigs accessing a feeder space will reduce the number of meals
- pigs spend about 40% less time eating pellets than mash
- eating behaviour is variable
- Pigs can maintain feed intake levels despite varying environmental conditions
What is the equation for food intake for grazing animals?
1 pt
food intake, g/d = grazing time (min/d) x biting rate (n/min) x bite size (g)
What are methods for finding food intake for grazing animals?
3 pts
- using digestibility and fecal collection
- difference between forage mass before and after grazing
- feeding behaviour, bits, biting rate and grazing time
How does environment (stress) affect feed intake?
5 pts
- Most work conducted with lab animals
- Response dependent upon duration of stressor and whether the stress is physical or physiological
- In rats, mild stressors such as a pinch will stimulate feeding and drinking following the stress
- More extreme stress inhibits feed intake
- body weight reductions observed with stress only slowly regained
What are some issues with feed quality?
3 pts
- High or low energy concentration
- Toxic compounds
- Nutrient deficiencies
