Mineral requirement of high-yield sows

How to meet the mineral nutrition needs of high-yield sows?-- the mineral needs of high-yield sows are not clear. So far, studies have confirmed that with the increase of parity, the reserves of major and trace elements in sows are gradually decreasing, and high fecundity aggravates the loss of minerals. In some periods of the reproductive cycle of sows, usually in the later stages of pregnancy and lactation, there is a high demand for major and trace elements. But other periods are equally important. However, simply increasing the contents of major and trace elements in the diet of sows may not be an ideal method, because this way may reduce the reproductive performance of sows. Recent studies have shown that organic trace elements can increase the litter size of sows after 6 parities. Studies have shown that although organic selenium can improve the reproductive performance of sows, other trace elements may also play a corresponding role in improving the reproductive performance of sows. Effects of trace elements on reproductive performance of sows our previous reports showed that total litter size and live litter size of sows decreased when the content of inorganic trace elements in diet exceeded the recommended requirement of NRC, but increased when fed with organic trace elements (Bole series organic trace elements, Altege) (figure 1). In addition, when the calcium and phosphorus added to the diet during pregnancy exceeded the NRC requirement (1998), the decline in reproductive performance of sows was aggravated. The sources of trace elements in diets are generally organic trace elements or inorganic mineral salts (usually in the form of sulfate). Based on the study of organic trace elements in Baile and a study on the reproductive performance of sows (this study evaluated the efficacy of organic selenium sources-selenite (Altege) and inorganic selenium sources-sodium selenite. As shown in figure 2, the addition of selenite and organic trace elements can increase litter size. The addition of organic trace elements to the diet could increase about one piglet per litter, while the addition of selenite alone could only increase about 0.3 piglets per litter. Although the statistical difference of these data was not significant, the addition of organic trace elements (including selenite) was more effective than that of selenite alone in increasing litter size. Figure 1. Effects of dietary trace element sources and levels on reproductive performance of sows with more than 6 parity (nasty 375 litters) figure 2. Comparison of the effects of trace element sources on litter size in sows in two experiments We made another comparison of these studies. The Serle selenium trial of Mahan and Peters (2004) and the organic trace element study of Peters and Mahan (to be published) showed that the calcium level in the pregnancy diet was 1.0%, which was slightly higher than that recommended by NRC (1998), but it was similar to that in the commercial sow diet during pregnancy. In the Peters and Mahan (to be published) study, sows fed diets supplemented with NRC recommended levels (calcium and phosphorus) had lower litter size than those supplemented with Bailue or inorganic trace elements (figure 1). From the comparison of the data of the two experiments, it can be concluded that the sows fed with organic trace elements or selenite diets had higher litter size, but there was no significant difference in the overall litter size between the two experiments (figure 3). It should be pointed out that the level of management and facilities used in the two trials are the same, so the difference in the results is more due to the influence of dietary minerals in sows than the management level of sows. As the mineral loss of sows has been widely recognized in the breeding industry, it is a common practice to feed pregnant sows with high calcium diets. High productivity can lead to further loss of mineral reserves in sows (figure 4). This may be due to the negative effects of high levels of calcium in the diet on other trace elements in the digestive tract (figure 5). It is well known that calcium can chelate with other major elements (such as phosphorus, sulfur) and some trace elements (such as iron, zinc and copper) to reduce their absorption and bioavailability. In the early stage of pregnancy, sows need less calcium for fetal development than during late pregnancy or lactation, and dietary calcium and phosphorus levels can be adjusted appropriately. During each reproductive cycle, the mineral needs of sows during pregnancy and lactation are not constant. Figure 3. Effects of dietary trace elements on litter size when sows were fed high calcium pregnancy diets in two experiments. Mineral loss in sows after the third birth (compared with non-pregnant sows) figure 5. The absorption principle of calcium and phosphorus when the fetus's minerals need fetal development, the speed of tissue development is different, so a variety of nutrients are needed. We analyzed the total mineral content of the fetus from 45 days of pregnancy to birth, and the data showed that in the last 14 days of pregnancy, the sow devoted about 50% of the total mineral mass to fetal development (figure 6). Therefore, the fetus's need for trace elements in sow diet and its own mineral reserve play an important role in the normal development of fetal tissue, especially the fetus, its main stage of growth and development is in the third trimester of pregnancy. Compared with the early developmental period, pigs in the second week of pregnancy had higher requirements for calcium and phosphorus. As can be seen from figure 7, a litter of 12 piglets needs about 73 and 44 grams of calcium and phosphorus, respectively, two weeks after this pregnancy. Although the fetal demand for these major elements increases linearly throughout the cycle, pre-natal needs are the most critical. Therefore, the fetal need for calcium and phosphorus in sows may lead to mineral loss and bone damage in the bones of sows during pregnancy. Figure 6. The total amount of minerals in the fetus (from 45 days of pregnancy to birth). Figure 7. The total amount of calcium and phosphorus per litter (from 45 days of pregnancy to birth) in developing fetuses during 45 to 114 days of pregnancy has a similar trend to the need for trace elements and major minerals, although the requirements are relatively low. As shown in the figure, the deposition of iron (figure 8) and zinc (figure 9) in different days of pregnancy clearly shows that the deposition of trace elements is the highest in the second week of pregnancy, and other trace elements have the same trend. These results showed that pregnant sows had higher requirements for trace elements in the second trimester of pregnancy, and the sows with large litter size had higher mineral requirements than those with low litter size. Figure 8. Fetal total iron content / litter (45 days of pregnancy to birth) figure 9. Total fetal zinc content / litter (45 days of pregnancy to birth) Mineral needs of nursing pigs in order to meet the needs of the fetus, late-pregnant sows have a high demand for minerals, but lactating sows need more of these minerals. Figure 10 shows that two sows with a litter size of 11 and 8 need 85 and 68 grams of minerals per day respectively to meet the growth needs of piglets. The calcium requirements of two litters of piglets in the last 10 days of 21-day lactation were 19.0 and 13.3 g / day, respectively (figure 11). In the first 11 days of lactation, the mineral requirement of piglets was higher, and the mineral deposition of two litters of piglets was 11.7 and 4.7 g / day, respectively. Therefore, the mineral requirement of piglets increases with the increase of lactation or sow milk production. If the calcium or phosphorus requirements are expressed on a per piglet basis, the calcium and phosphorus contents of each piglet in the two litters are similar (to be published). Figure 10. The total mineral content of each litter of the two litters at birth, 11 and 21 days of age (11 litters compared with 8 litters) the contents of various trace elements in the two litters are shown in figures 12 to 16. The content of zinc has the same trend as that of major elements (figure 12), that is, the more litter size, the higher the content of trace elements. However, when the zinc content is converted into the daily content, the increase rate of zinc content is not the same as that of calcium content. Figure 11. The content of total calcium in each litter of two litters at birth, 11 and 21 days old (compared with 11 litters and 8 litters). The total zinc content of piglets in each litter of the two litters at birth, 11 and 21 days old (11 litter size and 8 litter size), although the piglets with 11 litter size stored more zinc in the first 11 days of lactation, the level of zinc was higher than that in the last 10 days of lactation. This difference may be more pronounced for iron and copper reserves at different stages of lactation. During the 21-day lactation period, the daily reserves of iron (figure 13) and copper (figure 14) were higher in the first 11 days than in the last 10 days. Figure 13. The total iron content of two litters of piglets at birth, 11 and 21 days of age (11 litters versus 8 litters) figure 14. The total copper content in each litter of two litters at birth, 11 and 21 days old (11 litters versus 8 litters) Fig. 15. Iron content of each piglet at birth, 11 and 21 days old (11 litter size compared with 8 litter size) figure 16. Copper content of each piglet at birth, 11 and 21 days old (11 litter size and 8 litter size) conclusion the dietary mineral level of high-yielding sows is higher than that recommended by NRC (1998). We need to do more experimental studies on the mineral requirements of sows. Simply increasing the level of minerals may be a mistake. For example, studies have shown that feeding sows a diet containing 0.1% calcium throughout pregnancy may reduce the number of piglets born in litters. However, it is certain that the demand for calcium and phosphorus in sows increases in the third trimester of pregnancy and throughout lactation. Understanding the trace element requirements of breeding sows plays a key role in improving the reproductive performance of breeding pigs. This study shows that the use of organic trace elements can increase the number of litter piglets compared with inorganic salts. It is not clear which trace elements play a role, but the results show that the increase in litter size is not just due to the addition of selenium. The level of mineral nutrition during pregnancy will affect the number of piglets born in the litter, but the optimal dietary mineral level is not clear. The results show that high fecundity sows may not be able to meet the needs of piglets for trace elements during the 21-day lactation period. Therefore, consideration is given to adding higher levels of minerals, but it has not yet been confirmed whether this is appropriate. The charts and data have not been sent up. The original author and the translator need to be marked.