Unlocking the Secrets of Calcium Management in Poultry: A Comprehensive Guide

Calcium (Ca) is a crucial nutrient in poultry farming, playing a vital role in the development and maintenance of strong bones, eggshell formation, and overall health of the birds. Here's a comprehensive and practical guide on the importance and management of calcium in poultry diets.

Key Takeaways from this article:

1. Calcium is essential for bone growth in chicks and eggshell formation in laying hens.
2. Growing chicks require 1% calcium while laying hens need about 3%.
3. Insufficient calcium can lead to rickets in chicks and osteomalacia in layers.
4. Common calcium sources include chalk powder, limestone, marble chips, oyster shells, and steamed bone meal.
5. Layers prefer granular calcium, while chicks need fine powder.
6. The balance between calcium and phosphorus is crucial; high phosphorus can be harmful.
7. Increase calcium supply during summer (4g to 5g per bird per day) to counter heat stress effects.
8. Administer calcium in the late evening for availability during the night for eggshell formation.
9. Half of the diet's calcium should be coarsely ground, and the other half as grit.
10. In hot climates, increase dietary electrolytes like chlorine, potassium, and sodium.

Importance of Calcium in Poultry Diets

1. Bone Growth and Maintenance: Growing chicks require about 1% calcium in their diet for proper body growth and skeleton build-up. Calcium deficiencies in chicks can lead to conditions like rickets, characterized by weak bones.
2. Eggshell Formation: For laying hens (layers), the calcium requirement is higher, approximately 3%. This higher level is essential for the production of eggs with strong, thick shells. Inadequate calcium intake in layers can result in reduced egg production, poor eggshell quality, and in some cases, the production of shell-less eggs. Osteomalacia, a condition resulting from calcium deficiency, can occur in laying birds.
3. Dietary Management: The diet of layers should ideally comprise half coarsely ground calcium sources and half as grit. This approach allows the hens to select and consume calcium as per their need, maintaining the palatability of the feed.
4. Sources of Calcium: Common sources of calcium for poultry include chalk powder, limestone, marble chips, and oyster shells. These sources typically contain about 33 to 38% calcium content. Marble chips are a good source of granular calcium supplement, particularly beneficial for layers. Oyster shell has a higher bio-availability of calcium compared to chalk powder or limestone. Steamed bone meal is also an effective calcium and phosphorus source, containing 24-26% Ca and 12-13% P.

Calcium Management Strategies

Adjusting Calcium Levels in Laying Hens

1. Increased Demand During Egg Laying: When hens start laying eggs, their calcium needs significantly increase. This is because a large amount of calcium is required for the formation of eggshells.
2. Recommended Calcium Levels: It is advised to increase the calcium content in the diet of laying hens to 3 to 3.5%. This elevated level ensures that there is sufficient calcium available for the high demand of eggshell production.
3. Sources and Forms of Calcium: This increase can be achieved by including high-calcium feed ingredients or supplements like limestone, oyster shells, or marble chips. The choice of the calcium source should also consider the particle size preference of layers, which is granular.

Heat Stress Management in Layers

1. Effects of Heat Stress: Heat stress can adversely affect layers, leading to decreased feed intake, reduced egg production, smaller egg size, and poorer eggshell quality.
2. Increasing Calcium Supply: To mitigate these effects, it is recommended to increase the daily calcium supply from 4g to 5g per bird during the summer months.
3. Timing of Calcium Supplementation: Providing calcium in the form of granular shell grit during the afternoon or evening is beneficial. This timing ensures that calcium is stored in the gizzard overnight, where it is gradually released and used for eggshell formation.

Evening Feeding of Calcium

1. Storage and Utilization of Calcium: Administering calcium in the late evening hours has the advantage of storing calcium in the gizzard. Here, it slowly dissolves due to the action of hydrochloric acid produced in the proventriculus.
2. Availability During Eggshell Formation: Since eggshell formation primarily occurs at night, this strategy ensures that calcium is readily available when the hen needs it most. This is particularly effective because feeding activity is generally low during the dark hours, so the calcium consumed earlier can be fully utilized for eggshell production.
3. Practical Implementation: To implement this strategy, Vets/farmers should provide a calcium supplement, preferably in a granular form, during the late evening. This can be part of the regular feed or offered separately to ensure that hens consume the required amount.

Practical Considerations

Particle Size in Calcium Supplementation

1. Layers: For laying hens, the calcium supplements should be in a granular form. This particle size is more palatable for layers and aids in the gradual release of calcium, which is essential for continuous eggshell formation. The granular form can be obtained from sources like marble chips or coarse oyster shell grit.
2. Chicks: Young chicks, on the other hand, prefer calcium in a fine powder form. This is because their smaller beak size and digestive system are more suited to finer particles. Fine powdered calcium can be sourced from finely ground limestone or chalk powder. The finer particles are easier for chicks to ingest and metabolize, which is crucial for their rapid growth and skeletal development.

Balancing Calcium with Phosphorus

1. Importance of Ratio: Calcium (Ca) and phosphorus (P) need to be balanced in poultry diets to ensure optimal health and productivity. An imbalanced ratio can lead to health issues such as weak bones in chicks and poor eggshell quality in layers.
2. Risks of High Phosphorus: High levels of phosphorus, relative to calcium, can be particularly harmful. This is especially true in conditions of elevated temperature, where the detrimental effects of an imbalanced Ca:P ratio may be exacerbated. Excessive phosphorus can interfere with the absorption and utilization of calcium, leading to deficiencies even when adequate calcium is present in the diet.
3. Recommended Ratios: While the exact ratio can vary depending on the life stage of the bird and specific dietary formulations, a general guideline is to maintain a Ca:P ratio in the range of 2:1. This ratio helps in preventing conditions like rickets in chicks and osteomalacia in layers.

Dietary Electrolytes in Hot Climates

1. Role of Electrolytes: Electrolytes like chlorine, potassium, and sodium play a crucial role in maintaining cellular function and fluid balance in poultry. They are particularly important in regulating body temperature and acid-base balance.
2. Heat Stress: In hot climates, poultry are more prone to heat stress, which can impact feed intake, egg production, and overall health. Heat stress leads to increased respiratory rate and water loss, disrupting electrolyte balance.
3. Supplementation Strategies: To counteract the effects of heat stress, it's advisable to increase the levels of dietary electrolytes. For instance, increasing the levels of chlorine, potassium, and sodium by 1.5% for every degree Celsius above 27°C can help maintain electrolyte balance, reduce heat stress, and support optimal physiological functions.
4. Consideration of Vitamin Supplementation: Alongside electrolytes, vitamins like Vitamin A and Vitamin C might have higher requirements in hot climates. Vitamin C, in particular, is beneficial in stress conditions and can be supplemented at a rate of 200 to 600 mg per bird per day, especially in the late evening hours when it can be effectively utilized for metabolic processes.

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