2.3 Laying Hens - T2 Flashcards
How do we get a flock “to the starting line” and how do we get production to start?
Use feed management to get the flock to the starting line
Use photostimulation to start production
Generally, what happens at the start of production to nutrient requirements?
Sudden, drastic changes in requirements
- Feeding programs need to reflect this
- Cumulative effects of nutrition and management
- Long laying cycles (70 wks in Canada)
Phase feeding for laying hens is not based on age, it’s based on what?
Egg mass/hen/day
- reflects nutrient requirements
- feed based on expected intake, not a fixed % of diet
When does phase feeding change in layers?
Phase changes based on egg mass output (daily egg mass; g/hen/day); decreases with age
-% production peaks then gradually comes down
- but egg wt increases with age
- CP goes down with age
- Ca goes up with age bc Ca metabolism efficiency goes down
- P goes down
What is the biggest factor driving nutrient requirements in laying hens?
Average daily egg mass (g/hen/day)
- drives changes in requirements
- reduce nutrient content after peak egg mass
If production drops what does that tell us about nutrient density?
If production drops, decrease in nutrient density is too severe
Phase feeding is switched based on average daily egg mass. What are 2 other factors to keep in mind?
- Nutrient density
- Temperature
- birds will reduce feed intake if it’s hot and humid
As hens age, protein is reduced. What else happens?
- Feed intake INCREASES with age
- lower nutrient density diets
- reduce feed costs - Egg mass output decreases
- egg numbers decrease
- average daily egg mass increases, then decreases - Limit egg size increases
- eggshell quality
- no price premium for XL and J eggs
When phase feeding laying hens, what happens to calcium over time? Phosphorus?
Calcium increases
- reduced efficiency of Ca absorption, metabolism with hen age
- want to avoid limiting Ca for eggshell deposition
Available phosphorus decreases
Egg-type birds (layers) have what type of appetite? How does this affect how they are fed?
Low appetites
- allow birds to consume feed ad libitum
- at higher intakes, can decrease nutrient density
Drops in production are associated with what?
Major, rapid changes in diet formulation which negate the advantage of lower cost diets
- lower production
- increased mortality rate
What type of feed texture do layers prefer?
- large particles of feed
- usually fed a mash diet
- increase in nutrient density with pelleted feed
*if we are concerned about feed intake, consider texture
What is the Ca particle size inclusion in layer diets?
- 2/3 large particle; retained in gizzard
- 1/3 small particle; quickly available
Why?
- better quality egg shell if Ca is from the gut vs. mobilized from bone
What is the thermoneutral range of laying hens? What happens above or below?
Range is 19-27
- behavioural changes above and below
- above 27, energy intake decreases and cannot meet demands for egg production
- above 33, energy intake is below maintenance requirements
- effects vary with air speed, feathering, etc.
How can heat stressed be managed?
- increase dietary energy with fat
- decreased feed intake, but still greater than if energy density not increased
- imperfect control mechanism of birds
- lower heat increment - stimulate feed intake by “stacking”
- feeding more times per day to reduce heat increment
- feed at cooler times of the day (midnight feeding) - texture
- birds prefer small crumbles
- reduce feed dustiness
