Key points of calcium supplement for laying hens

In order to increase the yield of hens and reduce the damage rate of eggs, the supply of calcium should be checked during the laying period. Feed is the main factor that determines the quality and strength of eggshell. The experiment showed that the deposition of calcium in the hen bone was enhanced half a month before the beginning of laying. Therefore, from the age of 4 months to 5% of the laying rate, hens should be fed ingredients with high calcium content. It is now generally believed that the best level of calcium in the diet of laying hens is 3.2%-3.5%, while in the case of high temperature or high laying rate (75%-80%), the calcium content can be increased to 3.6%-3.8%. In the short term, increasing to 4% can make the eggshell thicker, but further improvement is not good for laying eggs, nor can it improve the quality of eggshells. Insufficient calcium in feed will promote eating, resulting in excessive feed consumption, weight gain of hens and more fat deposition in the liver; the supersaturated calcium content in feed will lead to loss of appetite of chickens. When the ground is flat, you can put several feeding troughs specially equipped with coarse sand grains and broken shells in the chicken house to allow the chickens to feed freely.

In general, hens have enough calcium in their bones to form several eggs. when they do not get enough calcium from the feed, the eggshell will become worse, lay soft or shellless eggs, or even paralyzed. The longer the calcium in the bone is called to form the eggshell, the weaker the eggshell strength.

The hens feel calcium deficiency during the formation of eggshells at night. During the period of light, the calcium eaten by chickens in the first half of the day passes through the digestive tract, is absorbed into the blood in the small intestine, deposits in the bones, and then moves to form eggshells when necessary. Only the calcium eaten in the second half of the day is directly used to form eggshells. Therefore, it is best to supplement calcium to the hens at 12: 20, so that when the hens eat calcium freely, they can adjust the amount of calcium by themselves. For example, during eggshell formation, calcium intake is 92% under normal circumstances, but only 68% during non-formation. Hens with lower body weight and less food should be fed more calcium.

Shell and stone powder are commonly used as calcium sources. When the dietary shell and stone powder are 2 ∶ 1, the eggshell strength is the best. Chickens have the best absorption of animal calcium sources, poor absorption of plant calcium sources, and high-temperature sterilized eggshells are the best calcium sources.

In the experiment of hybrid chickens, when the shell breaking rate of 61-week-old chickens reached 3.5%, 2% of the total amount of granular shell powder was added in the afternoon, the eggs were significantly reduced, the eggshells were smooth, and the average egg-breaking rate was only 1.59% at the age of 72 weeks, with good results.

The proportion of calcium, phosphorus and vitamin D3 has an effect on the strength of eggshell. Calcium 3% calcium 3.5%, phosphorus 0.45% is the best, while the standard of vitamin D3 is 10-12 times that of vitamin A. Calcium determines the brittleness of eggshell and phosphorus determines the elasticity of eggshell. Vitamin D3 deficiency destroys the balance of calcium in the body, resulting in defective eggshells. Generally speaking, the eggshell quality of the eggs laid at 14: 17 in the afternoon is very good, which is mainly related to the prolongation of the interval between laying eggs and adequate calcium supplements for chickens.