Depletion of Femur Bone Mineral after the Onset of Egg Production in a Commercial Strain of Leghorns and in Broiler-Type Pullets

Cox, Allan C.; Balloun, S. L.

doi:10.3382/ps.0501429

Cited by 10 publications

(4 citation statements)

References 3 publications

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“…Hurwitz and Bar (1969) stated that the function of bone in supplying calcium in egg shell has been considerably overestimated and that sufficient amounts of calcium for shell formation could be supplied by the intestine, and little, if any, calcium is needed from bone when the dietary calcium supply is not limiting. However, evidence presented by Cox and Balloun (1971) and that presented by Taylor (1961) does not support the Hurwitz and Bar (1969) opinion.…”

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confidence: 58%

Influence of Dietary Calcium on Bone Calcium Utilization

1986

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In Experiment 1, 10 microCi 45Ca/day were administered to 125 hens for 10 days. Hens were then allocated to five treatments with calcium levels ranging from .08 to 3.75% of the diet. In Experiment 2, hens with morning oviposition times were randomly allocated to 11 treatments that were periods of time postoviposition ranging from 6 hr to 24 hr, in 2-hr increments (Experiment 2). At the end of each 2-hr period, eggs from 25 hens were removed from the uterus. The 18-, 20-, and 22-hr treatments were replicated three times. In Experiment 3, hens were fed either ad libitum or feed was withheld the last 5 or 6 hr before oviposition. In Experiment 4, hens were fed 10 microCi of 45Ca for 15 days to label skeletal calcium. Hens were divided into two groups and fed a .08 or 3.75% calcium diet for 2 days. On the second day, 25 hens fed the 3.75% calcium diet were intubated with 7 g of the same diet containing .5 g calcium at 1700, 2100, 0100, 0500, and 0700 hr. The measurements used were egg weight, shell weight, and 45Ca content of the egg shell. Results indicated a significant linear or quadratic regression of dietary calcium levels on 45Ca accumulation in eggshells and eggshell weight (Experiment 1). As the calcium level of the diet increased, eggshell weight increased and 45Ca recovery decreased. Utilization of skeletal calcium for shell formation ranged from 28 to 96%. In Experiment 2, the rate of shell calcification was not constant throughout the calcification process but varied significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

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confidence: 58%

Influence of Dietary Calcium on Bone Calcium Utilization

1986

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“…There are several situations in which expressions involving external bone V may be informative. These include the study of bone mineralization with onset of production (Hurwitz, 1964;Cox and Balloun, 1971b), calcium depletion and repletion in hens (Hurwitz and Bar, 1966), and the problem of bone fragility in spent hens (Rowland et al, 1972). Hurwitz (1964) remarked that "ash percentage in three femur segments was influenced neither by dietary calcium nor by egg laying."…”

Section: •V' Cjr 'P^ Discussionmentioning

confidence: 98%

External Bone Volume, Ash, and Fat-Free Dry Weight of Femurs of Laying Hens Fed Diets Deficient or Adequate in Phosphorus

1982

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The femurs of laying hens fed diets containing .18, .23, or .43% available phosphorus were evaluated. External bone volume (V) and organic matter (OM) content and OM/V were not different. Ash (A), percent bone ash, and A/V were significantly less at the two lowest levels of dietary phosphorus. It was concluded that the femurs of phosphorus deficient laying hens have a reduction in mineral content but not organic matter, Determination of external bone V and expression of A/V may be of value in assessing osteoporotic bone. (

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“…The bone mass loss which accompanies bone fragility occurs with aging, and is particularly prevalent in caged layers even though it does occur in floor hens to a lesser degree. Cox and Balloun (1971) demonstrated that bone mineral depletion commenced with the first egg laid and progressed rapidly for the first 30 eggs laid. This process occurs until a point is reached beyond which a further reduction in bone mass will result in a bone fragility problem which can be of economic importance to the processor of spent hens.…”

Section: Introductionmentioning

confidence: 98%

Time Required to Develop Bone Fragility in Laying Hens

Rowland¹,

Harms²

1972

Poultry Science

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Two experiments were conducted to determine the length of time necessary to produce bone fragility in caged layers. Tibia ash and bone breaking strength of caged and floor pullets were found to be higher in floor pullets after four weeks, with a maximum difference between groups occurring at the end of eight weeks. Both groups exhibited a slight decrease in both tibia ash and bone breaking strength which was not statistically significant with each successive month of lay. It was further observed that tibia ash was closely associated with breaking strength, but was not as sensitive a measurement of bone fragility as was breaking strength.

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Depletion of Femur Bone Mineral after the Onset of Egg Production in a Commercial Strain of Leghorns and in Broiler-Type Pullets

Cited by 10 publications

References 3 publications

Influence of Dietary Calcium on Bone Calcium Utilization

Influence of Dietary Calcium on Bone Calcium Utilization

External Bone Volume, Ash, and Fat-Free Dry Weight of Femurs of Laying Hens Fed Diets Deficient or Adequate in Phosphorus

Time Required to Develop Bone Fragility in Laying Hens

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