一. Use inferior stone powder
It was found that the calcium content of the feed was 1/3 lower than the standard. It was further found that the calcium content of the stone powder used was only 22%, which was 1/3 different from the normal calcium content of 35%-38% of the stone powder. By testing the stone powder, the stone powder was determined as dolomite.
At present, the main raw materials used in the production of stone powder are calcite and limestone, usually calcite and limestone contain more than 33% calcium, high quality can reach 35%-38%. Calcite is usually white or five colors, limestone is light gray or light yellow, so it is used to calcite powder called white stone powder, lime stone powder called bluestone powder, is commonly used in laying hens calcium source feed.
The content of calcium in dolomite is 22-24%, and the content of magnesium is too high, which is 10%. Too high magnesium will affect the absorption of calcium, iron and copper, so dolomite is not suitable for the calcium source feed of laying hens. Dolomite is usually white, and calcite is usually white. In production, dolomite is often used as calcite, resulting in insufficient calcium content, leading to a decrease in egg production rate.
二. Overfine pulverization of stone powder
The egg shell quality of 220-day-old laying hens in the chicken farm has been poor, manifested as light color, crisp quality, sandiness, lackluster, soft shell, higher proportion of broken eggs, and occasional pecking of eggs. However, there were no abnormal drinking water intake, normal feces, good spirits, and little difference in egg production rate between the chickens and other flocks. After the exclusion of diseases and other factors, it was found that all the stone powder used was fine stone powder, and then the fine stone powder was replaced with the fine stone powder with the fine stone powder, and the problem was solved.
The stone powder used in laying hens should not be crushed too fine, because the retention time of small calcium particles in muscle and stomach is short and the utilization rate is low, which will lead to the quality of eggshell decline. Research shows that stone powder granularity mix in with size 6-8 mesh powder (75%, 12.5%, 10-12 mesh stone powder with 12.5% 50 mesh powder) broken egg rate is the lowest, eggshell intensity is the largest, because the size of the particle size mixture can evenly for calcium, so as to guarantee the quality of shell, and larger particles in the muscular stomach with sand grinding effect, can promote the digestion of feed.
三. Zeolite powder was mistaken for stone powder
Some chicken farm 260 days old laying hens egg production rate dropped sharply, soft shell eggs, thin shell eggs, appetite, spirit can be, a few standing difficult, flexuous claws, preliminary determination and calcium phosphorus deficiency, inspection found small stone powder particle size, color is light bluish white, bulk density is significantly small, assay calcium content is only 2.4%, can be determined as zeolite powder. Change zeolite powder to stone powder, 5 days later, the chickens are basically normal.
Zeolite is a kind of aluminum silicate minerals, containing more than 20 elements, multiple holes, strong adsorption function, antibacterial, promote growth, reduce fecal odor, can be used as an additive, but due to the calcium content of only about 2%, can not be used as a calcium source feed instead of stone powder, otherwise it will lead to feed calcium serious shortage. In addition, the wheat rice stone; Sepiolite and zeolite similar, should be different from stone powder, farmers should improve the ability to identify, avoid misuse.
四. The amount of stone powder is relatively too large
Some chicken farm 160 days of age spirit of laying hens, well appetite, water quantity increase, part of the waste white water-like loose stool, there are a few dead chickens, autopsy observed in kidney is porphyritic flowers, filled with ureter with white lime, needle-like urate crystals found under microscope, a diagnosis of gout, check formula found powder dosage, 8.5% bone powder 2.5%, calcium content is 3.78%, and the metabolism can only 10.3 million kilojoules/kg, can determine the diet metabolizable energy is low, high calcium content, the early feed intake, lead to excessive calcium intake, sedimentary more cause gout. It was inquired that the high calcium content of the diet was caused by the substitution of stone meal and bran in order to reduce the cost and use of corn due to the rising price of corn. After adjusting the formula, the metabolic energy was 11.3 mj/kg and calcium was 3.30%. After 2 weeks, the chicken population was normal.
The laying hens feed on energy, the dietary energy value is high and the food intake is small. Low energy value, large feed intake. In combination with the diet, the metabolic energy and other nutritional indicators should be kept basically constant, otherwise, it is easy to lead to insufficient or excessive nutrition. The ratio of metabolic energy and calcium of high-yielding layer hens should be 3.4-3.5. When the metabolic energy is reduced or increased, the calcium should also be reduced or increased, and the dosage of stone powder should also be changed accordingly.
