Layer chickens need a lot of calcium and phosphorus during the egg laying period, of which about 90% of calcium is used for bones and eggshells, about 80% of phosphorus is composed of bones together with calcium, and the rest of calcium and phosphorus are distributed in various tissues throughout the body, and the eggshell of the layer chicken accounts for about one-tenth of the egg weight, of which 90% of the eggshell is calcium carbonate. An egg weighing about 50-60 grams has a water content of 4.5-5.4 grams of calcium carbonate, according to the utilization rate of calcium is 60%, each egg needs about 10 grams of calcium carbonate, and 3.5 grams of pure calcium. However, the body calcium in the chicken body is only limited to about 15 grams, according to the needs of egg laying, the hen's body (including bone calcium) is only enough to produce 3-4 eggs, so it is necessary to supplement calcium in large quantities. However, when supplementing calcium, be sure to choose a good source of calcium.
01, do not feed raw bone meal
Due to the different production processes of processing bone meal, the quality of its products varies greatly, so there are steamed bone meal and raw bone meal. Steamed bone meal is a product that is processed to remove most of the protein and fat, and then pressed, dried and crushed. Steamed bone powder is white or silvery gray, odorless, contains 30% calcium, 14.5% phosphorus, 7.5% crude protein, and 1.2% crude fat.
The so-called raw bone meal is an inferior bone meal produced under the condition of poor equipment. It is a simple rinse of the mixed bone and then steamed in a large pot for several hours, without pressure, without degumming, and then fished out of the pot, dried and crushed. This bone meal has a foul smell, is black or dark gray, contains 23% calcium, 10.5% phosphorus, 21% crude protein, and 5% crude fat.
If this raw bone meal is fed to layer chickens for a long time, because it is not treated with high temperature and pressure, bone calcium is combined with bone glue, and the absorption and utilization of calcium by the chicken body is much worse than that of steamed bone meal. Over time, it will cause imbalance in the proportion of calcium and phosphorus in chickens, resulting in a decline in the egg-laying capacity of layer chickens and causing major economic losses to chicken production. Therefore, chicken farmers, especially large-scale chicken farms, must pay attention to avoid feeding chickens with raw bone meal ingredients.
02, can not feed sheep bone meal
In places where sheep are raised more, people often process sheep bones into sheep bone meal and add it to livestock and poultry feed instead of other bone meal. This is okay for most livestock and poultry, and the effect is good, but not for laying hens. Because the eggshell of the egg is formed in the chicken body, the temperature should not be too high. And sheep bone powder is hot. When absorbed by layer chickens and used to participate in the formation of layer hen shells, the temperature in the chicken body will increase. This not only affects the formation of eggshells, but also reduces egg production rates. Therefore, layer chickens cannot be fed sheep bone meal.
03, it is best to choose a crude grain calcium source
During egg laying, the addition of calcium to the diet should be supplied in the form of shells or coarse-grained limestone, because this granular calcium leaves the muscula at a slower rate and is effective in strengthening the strength of eggshells that form eggshells at night.
Stone powder. Namely limestone powder, natural calcium carbonate. Generally containing about 38% pure calcium, it is the cheapest mineral feed to supplement calcium, and other purer commodities calcium carbonate, chalk soil and old lime also have the same effect as stone powder.
Shell powder. With shell powder as a calcium source feed, attention should be paid to the priority use of shells accumulated on the seashore for many years, because after a long period of accumulation, the attached organic matter has disappeared, and there are fewer bacteria; fresh shells should pay attention to disinfection, because the protein is spoiled, there are more bacteria and viruses attached, and the disease will often cause diseases to the chickens without disinfection. Generally, shell powder contains about 96.4% calcium carbonate, equivalent to 38.6% calcium.
04, calcium supplementation should be appropriate
Calcium supplementation for hens is not the more the better. Generally, hens need about calcium for each egg laid4. 4 grams, if the calcium content in the diet exceeds 4%, on the one hand, it will cause urate accumulation in the body, causing indigestion to cause dilution, and even the symptoms of gout; on the other hand, it will make the feed palatability worse, and the intake and egg production of the chickens will be reduced. Therefore, the calcium content in the feed of laying hens is generally 3. 0％—3． 5% is good, the feed source can be placed separately, allowing the chicken to feed, and can also be mixed with feed.
05, add vitamin C
In the stress state, vitamin C can also be added, which can promote the secretion of calcium from the bone marrow, and can also activate vitamin D3, which not only helps to improve the quality of eggshells, but also increases egg contents. The added dose of vitamin C in the diet should be added to 50 mg per kilogram of feed.