Calcium and Phosphorus Deficiency or Imbalance in Laying Hens
Happenings / Clinical Signs
The utilization of calcium and phosphorous depends on presence of an adequate amount of vitamin D in the diet
Calcium deficiency results in reduced egg production and thin-shelled eggs as well as a tendency to deplete calcium content of the bones. This condition may be associated with the syndrome commonly termed “cage fatigue”
- Egg production declines gradually
- Reduced egg production
- Increase the incidence of thin-shelled eggs
- Thin-shelled and soft-shelled or porous eggs
- Calcium and phosphorus deficiency result in reduced egg production and thin-shelled eggs
- Poor shell quality occurs most commonly in older flocks
- Egg shell weakness leads to loss of income due to egg cracks and breakage.
- Hairline cracks (Blind checks)
Visibly sick birds
- Birds are unable to stand, but willing to eat and drink
- Hens with cage layer fatigue have trouble standing and typically crouch or lie at the back of the cage.
- Birds often are alert
- Paralysis in severe cases
Lameness or unusual movement incoordination ataxia
- Paralysis due to the collapse of spinal bone (severe cases)
Neck wings breast abdomen shanks legs hocks feet joints vent skin
- Bone become so thin that spontaneous fractures may occur, especially in the vertebrae, tibia and femur
- Fractures of ischium, humerus, and keel bones show the highest incidence, follow by fractures of pubis, ulna, coracoid and femur
- Bone fragility is responsible of up to 30% of fractures in commercial flocks during their life
- Low mortality or increases gradually
- Some birds have an egg in the oviduct and have die acutely
- Poor body fleshing condition
- Some birds die from dehydration (unable to reach the drinkers)
- Some birds have an egg in the oviduct and have die acutely (good body fleshing condition)
Diet or Feed Changes
- Recent Feed delivery
- Recent formulation / diet
In laying hens, calcium deficiency results in reduced egg production and thin-shelled eggs as well as a tendency to deplete calcium content of the bones. Finally, bones become so thin that spontaneous fractures may occur, especially in vertebrae, tibia, and femur. This condition may be associated with the syndrome commonly termed "cage fatigue".
Calcium and phosphorous are closely associated with metabolism, particularly with bone formation. The major portion of dietary calcium is used for eggshell formation in mature hens.
In addition to its role in bone formation, phosphorous is an essential component involved in the transfer or conservation of free energy in biochemical reactions. It is an integral component of many macromolecules and is involved in the regulation of many cellular and metabolic processes. Phosphorous also plays a critical role in the maintenance of acid-base balance.
The utilization of calcium and phosphorous depends on the presence of adequate amount of vitamin D in the diet.
- Causing Agents
- Calcium (Ca) and Phosphorous (P) deficiency or imbalance in the diet. Decreased of normal mineralization of structural bone and egg-shell. Calcium and phosphorous are closely associated in metabolism processes, particularly in bone and eggshell formation.
- Affected Systems/Organs
- Reproductive and locomotor systems
- Mainly Affects
- Egg production, egg quality and performance
- Supplementation of the diet with Vitamin D and appropriate Ca and P ratio and levels. The availability of phosphorous can be increased by inclusion in the diet of phytase of microbial or plant origin. The phosphorous in plant-base feedstuffs is poorly available because much of it is present in phytic acid and is not released by digestive enzymes.
- Suggested Actions
- Can be confirmed with clinical signs and gross lesions
- Technical assistance recommended
- Can be managed with feed additives, off-the-shelf medications
- Diagnosis should be confirmed with rapid assays and/or a certified laboratory
- Veterinary intervention is recommended
Impact on Egg quality
Impact on Liveability
Impact on Production
Overall Economic Impact
Y.M. Saif. 2008. Disease of Poultry. 12th Edition. page 1137,1157
David E. Swayne. 2013. Diseases of Poultry 13th Edition. page 1222,1240