Multiple factors can affect the eggshell quality and they are very diverse. This article focuses on defining and finding a solution to eggshell problems, caused by a deficient calcium absorption in the digestive tract and heat stress.

Calcium (Ca) requirements

Layers’ eggshells contain an average of 2 grams of calcium (that corresponds to the 8-10% of the total calcium weight in the organism).

98% of the birds’ calcium is in the bones, and the calcium supply to form the eggshell coming from the skeletal system depends on the diet:

• If diet’s calcium level is >3.65%: most of the eggshell Ca comes from the intestine.
• If diet’s calcium level is <3.6%: most of the eggshell Ca comes from the bones. For example, if the diet contains 1.95% of calcium, bones’ contribution in the eggshell calcium will be around 30-40%.

For this reason, it is important to:

• Supply the proper amount of calcium in the diet
• Make sure dietary calcium is absorbed (good status of the intestine)
• Make sure there is enough calcium stored in bones (minimize calcium excretion)

Calcium deficiency

Calcium deficiency leads to an increase of broken eggs because of the bad quality of their eggshell and skeletal problems (cage layer fatigue).

Layers can suffer from calcium deficiency, particularly in two situations:

• Intestinal dysbiosis: when there’s an imbalance of the intestinal microbiota and intestinal cells (enterocytes) can be affected, or when there’s an intestinal “overload” because the diets used for commercial breeds are highly concentrated.
• Heat stress periods: birds, to diminish their body temperature, increase the respiratory frequency (hyperventilation), which causes a reduction of the calcium stored in bones, since it is eliminated through the kidney.

1. The bird hyperventilates
2. Eliminates CO₂ and increases O₂ levels in blood
3. Low CO₂ levels à respiratory acidosis
4. Low quantity of carbonates (“C”) in blood, carbonates are stored in bones
5. The bird decomposes part of the bones to obtain carbonates
6. Calcium gets decomposed together with carbonates, and go to the circulatory system
7. Calcium level in blood increases
8. Calcium is excreted through the kidney

C) AVOID CALCIUM DEFICIENCY

• To increase calcium absorption in the intestine: pronutrients
  1. To optimize the regeneration of the intestinal mucosa: Intestinal Conditioners¹
  2. To optimize calcium absorption in enterocytes: Promoters of mineral absorption²
• To avoid calcium excretion due to hyperventilation: carbonates³

By supplying carbonates, the bird won’t decompose the bones during heat stress and will have enough calcium stored in its bones.

¹Intestinal Conditioner pronutrients can be found in the product Alquernat Nebsui

²Promoters of mineral absorption can be found in the product Alquernat Magacal

³Alquerfeed Ovoponedoras, is a product that supplies carbonates to avoid eggshell problems during heat stress periods.

You can read more about this topic at the following links:

Physiology of egg laying

Egg shell quality problems