Scientific pig raising 100 questions and answers 10. Copper, iron, manganese, zinc, cobalt, iodine and selenium in trace elements are

Copper is used in the body to synthesize hemoglobin, synthesize and activate some oxidases, and copper deficiency rarely occurs in pigs. The dietary copper 6mg/kg can meet the requirements of suckling piglets, and when the dietary copper content reaches 15mg/kg, it can meet the normal needs of growing pigs. When the dietary copper content of pregnant sows and lactating sows reaches 60mg/kg, it can increase the birth weight and weaning weight of piglets. A large number of studies have shown that high doses of copper can stimulate growth and improve feed utilization. Some people have found that copper fed with 250mg/kg can increase the daily gain of pigs by 9.1% and feed utilization rate by 7.4%. Long-term use of high copper will cause copper poisoning and damage liver and kidney function. For this reason, the United States no longer advocates the use of high copper, and even the UK, which has always used high copper, has changed its high copper dose to 160mg/kg. The suitable supplementary feeding amount of copper sulfate is between 125mg and 250mg. The formula used by the premix produced in our farm is 160g of copper per ton feed (160g/ ton full price feed), that is, 160mg copper per kilogram of compound feed (160PPM), and 250mg per kilogram of full price feed is the best. The experiment showed that when 255 mg of copper was added to each kilogram of compound feed, the growth rate of pigs was 17.4% higher than that of the control group, and the feed reward was increased by 16.9%. Too much will affect appetite and weight gain. Generally, the copper content of feed copper sulfate is 25%, and the copper content of air-blown powder containing five crystal water is 24.5%. When you use it, you can see the instructions. Iron is a component of most metabolic enzymes in the body. At the same time, it is an important component of hemoglobin, myoglobin, uterine ferritin, lactoferrin and other proteins. The sensitivity of pigs to iron is that suckling piglets are prone to iron deficiency anemia. When the content of calcium, phosphorus, manganese, copper, zinc and other elements in the diet is too high, it will affect the absorption of iron. The net iron requirements of piglets at different weeks were as follows: 1-week-old 70.3mg, 2-week-old 111.6mg, 3-week-old 170.2mg, 4-week-old 230.4mg, 5-week-old 294.3mg. Ferrous sulfate contains five crystal water (FeSO4 ·5H2O). The iron content is 22.5%. The iron content of air-blown powder is generally 30%. See the instructions for details. Our factory used to provide piglets with 144PPM per kilogram of feed, that is, 144g / ton full price feed. Manganese is a component of several enzymes, which participates in the metabolism of carbohydrate, fat and protein. When pigs were fed with insufficient manganese, the growth and ossification process were blocked, the fat deposition of carcass increased, and the reproductive function of sows decreased. When dietary manganese decreased from 36.95mg/kg to 25.74mg/kg, the above deficiency symptoms could be observed. At present, it is not possible to determine the appropriate content of manganese in pig diet, which is caused by the contradictory results of many experiments. Therefore, the recommended values of manganese requirements for pigs are 10mg/kg, 55mg/kg and 80mg/kg. German experts put forward that for pigs with a requirement of more than 20 kg, dietary manganese content is 20mg/kg, weaning to 20 kg body weight and sow diet manganese content is 30mg/kg. The manganese consumption of piglets provided by our factory is 50.52g/ tons of full price material, that is, each kilogram of full price material is 50.5PPM. Manganese sulfate contains a crystal water (MnSO4 ·H2O) with a manganese content of 31.8%, as detailed in the manual. It is better for suckling piglets to be supplemented with 2 mg manganese sulfate per kilogram according to their body weight. Zinc is a component of a variety of enzymes in the body. The zinc requirement of growing pigs is 40-170mg/kg and that of sows is 80-100mg/kg. The physiological effective dose of zinc is very different from the toxic dose. Pigs can tolerate 20-30 times of the normal amount of zinc, generally rarely occur poisoning caused by excessive zinc, and more zinc deficiency in the body. Zinc deficiency is common in growing and fattening pigs raised in cement fields. Zinc deficiency causes dermatitis of incomplete keratosis, hinders growth, poor growth of hair, that is, tinea, skin damage and so on. Zinc sulfate contains seven crystal water (ZnSO4 ·7H2O) contains 22.5% zinc, and air-blown powder contains 35% zinc, as shown in the product manual. The zinc content produced by our factory for piglets is 156g/ tons of full price feed, that is, 156PPM per kilogram of feed. According to the data, the effect of adding 100 mg zinc sulfate per kilogram of formula feed is better, the weight gain rate is increased by 64.15% compared with the control group, and the feed reward is increased by 20.67%. Generally, the addition of four-thousandths of zinc sulfate in formula feed can basically meet the needs. Cobalt can affect the synthesis of protein, nucleic acid, glycogen and phosphate in the form of vitamin B12, and there is usually no shortage of cobalt in pig diets. When the diet of pigs was deficient in cobalt, cobalt supplementation was beneficial to the synthesis of VB12 by intestinal microorganisms and increased daily gain and feed utilization. There is not much research data on cobalt requirement of pigs, and it is generally believed that cobalt deficiency can be avoided by dietary cobalt 1mg/kg. Cobalt in 400mg/kg can cause piglet poisoning. Selenium and vitamin E have protective effects on cobalt poisoning. Cobalt is not added to the premix we originally produced, but cobalt is added to the feed formula of Jiangxi Feed Factory. Iodine exists in the thyroid gland and affects substance and energy metabolism in the body by participating in the formation of thyroxine. Iodine deficiency in pig diet can reduce the synthesis of thyroxine and affect the metabolism of organic matter and mineral trace elements in the body, resulting in growth obstruction, reproductive dysfunction and iodine deficiency in pregnant sows, resulting in an increase in the number of stillbirths and a decrease in milk production. Piglets goiter, rough fur or hairless. The content of iodine in the diet is 0.2-0.3mg/kg, which can meet the needs of growing pigs. The iodine requirement of sows is 0.4-0.5mg/kg. Calcium iodate, potassium iodate and calcium periodate are nutritious iodized salts, which are more stable than sodium iodide and potassium iodide. Selenium deficiency in selenium pig diet can cause nutritional liver necrosis, morula heart disease or skeletal muscle degeneration, intestinal bleeding and other symptoms. Sudden death is a prominent feature of porcine selenium deficiency syndrome. Dietary vitamin E deficiency or environmental stress factors can easily lead to selenium deficiency symptoms. Many experiments show that the selenium content in the diet is between 0.1 and 0.3mg/kg, which can meet the normal needs of pigs. For mild selenium deficiency, 0.06mg selenium can be injected per kg body weight; for moderate selenium deficiency, 0.22mg selenium and 75IU vitamin E supplement can be injected per kg body weight; for severe selenium deficiency, 1.1mg selenium and 75IU vitamin E supplement can be injected per kg body weight, and the dietary selenium content can be maintained by 0.6mg/kg, plus 30IU vitamin E. Xiangying breeding Pig Co., Ltd. uses 1% selenium and piglet 20g/ tons of full-price feed. Selenium and vitamin E have similar antioxidant effects, and the symptoms of selenium deficiency are similar to vitamin E deficiency. The selenium requirement of pigs is 0.1 mg per kilogram of dry feed, and poisoning can occur when it reaches 5 mg. Proper methods should be adopted in feed processing, not only moisture-proof and moisture absorption, but also strict control and reasonable dosage. (this content is extracted from the "100 questions and answers on Scientific Pig raising" edited by Yingtan Old Science and Technology Workers Association and Zhang Genkai.)