Re-evaluation of calcium and phosphorus requirements in aged laying hens
| Autor: | Arie Bar, V. Razaphkovsky, E Vax |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Veterinary medicine
Aging Animal feed Eggs Oviposition chemistry.chemical_element Calcium Biology Phosphorus metabolism Egg Shell Animal science Animals Eggshell Calcium metabolism Phosphorus Nutritional Requirements General Medicine Animal Feed Breed Calcium Dietary chemistry Phosphorus Dietary Animal Science and Zoology Animal Nutritional Physiological Phenomena Female Chickens Food Science |
| Zdroj: | British poultry science. 43(2) |
| ISSN: | 0007-1668 |
| Popis: | 1. A series of 5 trials was conducted with 401- to 650-d-old Lohmann, Yafa (local breed with brown eggshells) and Yarkon (local breed with white eggshells) hens fed for 56 to 84 d with diets containing 25 to 50 g/kg calcium (Ca) and 4.5 to 7.6 g/kg phosphorus (P). 2. Increasing dietary Ca from 24-25 to 36-40 g/kg improved egg production, shell weight (SW) and shell thickness (ST), and decreased mortality. 3. Increasing dietary Ca to 48 to 50 g/kg did not affect egg production but increased SW and/or ST. In one out of the 4 trials, this effect was not significant, most likely because of the high shell quality of the eggs from the Yafa hens used for this trial. 4. Dietary P content of 4.5 g/kg (1.0 g/kg added inorganic P) appears to be sufficient for maintaining egg production and shell quality in aged laying hen given 36 to 40 g/kg Ca. 5. Increasing dietary Ca above 40 g/kg may require a higher dietary P content. |
| Databáze: | OpenAIRE |
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