Term
| Selection for high egg producing birds coupled with housing layers in cages have led to increases in... |
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Definition
-aggressive behavior
-cage fatigue
-skeletal problems
-cannibalism |
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Term
| Objectives of a layer breeding program |
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Definition
-To minimize mortality, by improving genetic resistance to disease and stress factors (high adaptability to different environments)
-To maximize the sale value of egg output, i.e. more eggs of preferred quality
-To minimize feed cost, or maximize egg income of feed cost
-To improve egg quality (external and internal), in line with specific market requirements |
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Term
| The decision to breed white or brown eggs should be based on... |
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Definition
1.How many eggs, white or brown a producer can sell at which price (or price differential)
2.The production cost of brown eggs versus white eggs |
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Term
| Some differences between white and brown eggs |
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Definition
-Persistency of lay: Better in white egg layers than brown egg layers
-Percentage of cracked and broken eggs: Higher in white eggs than brown eggs
-Percentage of blood spots: About equal
-Percentage of meat spots: Higher in brown eggs than white eggs |
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Term
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Definition
1. Value of saleable day old chicks per breeder hen
2 Value of saleable market eggs per hen
3. Carcass value of spent hen
4. Cost of feed consumed per hen |
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Term
| Main trait groups in layers |
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Definition
-Egg production
-Product quality
+outer
+inner
-Production efficiency
-Reproductive performance
-Functional traits |
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Term
| Egg production traits in layers |
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Definition
-Age at first egg
-Hen day egg production
-Persistency of lay
-Molt (Pause) |
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Term
| Product quality traits in layers |
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Definition
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Term
| outer egg quality traits in layers |
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Definition
Egg shell quality including
1 Cracks and hair-cracks
2 Pinholes
3 Shell thickness
4 Shell color
5 Shell porosity
6 Egg shape |
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Term
| inner egg quality traits in layers |
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Definition
-Albumen quality
-Blood and meat spots
-Haugh units
-Yolk color
-Taste and smell |
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Term
| Production efficiency traits in layers |
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Definition
-Housing and mature body weights
-Feed efficiency |
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Term
| Reproductive performance traits in layers |
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Definition
-Female and male fertility
-Hatchability
-Livability |
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Term
| Functional traits in layers |
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Definition
-Disease resistance
-Livability
-Cannibalism
-Temperament (e.g. flightiness)
-Leg strength
-Stress resistance
-Broodiness |
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Term
| A schematic three-way cross to produce the commercial layer |
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Definition
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