PMID- 12047091 OWN - NLM STAT- MEDLINE DCOM- 20030109 LR - 20191210 IS - 0007-1668 (Print) IS - 0007-1668 (Linking) VI - 43 IP - 2 DP - 2002 May TI - Re-evaluation of calcium and phosphorus requirements in aged laying hens. PG - 261-9 AB - 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. FAU - Bar, A AU - Bar A AD - Institute of Animal Science, Agricultural Research Organization, the Volcani Center, Bet Dagan, Israel. ariebar@agri.gov.il FAU - Razaphkovsky, V AU - Razaphkovsky V FAU - Vax, E AU - Vax E LA - eng PT - Evaluation Study PT - Journal Article PT - Research Support, Non-U.S. Gov't PL - England TA - Br Poult Sci JT - British poultry science JID - 15740290R RN - 0 (Calcium, Dietary) RN - 0 (Phosphorus, Dietary) RN - 27YLU75U4W (Phosphorus) RN - SY7Q814VUP (Calcium) SB - IM MH - Aging/metabolism/*physiology MH - Animal Feed MH - Animal Nutritional Physiological Phenomena MH - Animals MH - Calcium/metabolism MH - Calcium, Dietary/*administration & dosage MH - Chickens/metabolism/*physiology MH - Egg Shell/metabolism MH - Eggs MH - Female MH - Nutritional Requirements MH - Oviposition/drug effects/*physiology MH - Phosphorus/metabolism MH - Phosphorus, Dietary/*administration & dosage EDAT- 2002/06/06 10:00 MHDA- 2003/01/10 04:00 CRDT- 2002/06/06 10:00 PHST- 2002/06/06 10:00 [pubmed] PHST- 2003/01/10 04:00 [medline] PHST- 2002/06/06 10:00 [entrez] AID - 10.1080/00071660120121481 [doi] PST - ppublish SO - Br Poult Sci. 2002 May;43(2):261-9. doi: 10.1080/00071660120121481.