What are the mineral requirements of high-producing sows?
Mineral requirements of high-producing sows
How can the mineral nutrient requirements of high-producing sows be met?
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The mineral requirements of high-producing sows are still not very clear. Research to date has confirmed that, as parity increases, the sow's body reserves of macro- and trace minerals gradually decline, and high prolificacy further aggravates mineral loss. During the sow's reproductive cycle, there are certain periods, usually late gestation and lactation, when the requirements for macro- and trace minerals are very high. But other periods are equally important. However, simply increasing the macro- and trace mineral content of the sow's diet may not be the ideal approach, because this method may reduce the sow's reproductive performance. Recent research has shown that organic trace minerals can increase litter size after the 6th parity. Research has shown that, although organic selenium has the effect of improving sow reproductive performance, other trace minerals may also play a corresponding role in improving sow reproductive performance.
Effects of trace minerals on sow reproductive performance
Our previous reports showed that when the content of inorganic trace minerals in the diet exceeds the NRC recommended requirement, both the total number of piglets born per litter and the number of piglets born alive per litter in sows decline, but when organic trace minerals are fed (Bioplex series organic trace minerals, Alltech), litter size increases (Figure 1). In addition, when the calcium and phosphorus added to the gestation diet exceed the NRC requirements (1998), the decline in sow reproductive performance is aggravated. The sources of trace minerals in the diet are generally organic trace minerals or inorganic mineral salts (usually in sulfate form). This is based on research on Bioplex organic trace minerals and a study on sow reproductive performance (this study evaluated the efficacy of an organic selenium source - Sel-Plex (Alltech) and an inorganic selenium source - sodium selenite). As shown in Figure 2, the addition of both Sel-Plex and Bioplex organic trace minerals can increase litter size. After adding Bioplex organic trace minerals to the diet, approximately one more piglet per litter can be added, while adding only Sel-Plex can add only about 0.3 piglets per litter. Although these data are not statistically significantly different, numerically, the addition of Bioplex organic trace minerals (including Sel-Plex) is more effective in increasing litter size than the addition of Sel-Plex alone.
Figure 1. Effects of the source and level of trace minerals in the diet on the reproductive performance of sows beyond 6 parities (n=375 litters)
Figure 2. Comparison of the effects of trace mineral sources on sow litter size in two trials
We also conducted another comparison of these studies. In the Sel-Plex trial study by Mahan and Peters (2004) and the Bioplex organic trace mineral study by Peters and Mahan (unpublished), the calcium level contained in the gestation diet was both 1.0%, slightly higher than the NRC (1998) recommendation, but it was comparable to the content in commercial sow gestation diets. In the study by Peters and Mahan (unpublished), compared with sow diets supplemented at the NRC recommended levels (calcium and phosphorus), litter size was lower when Bioplex or inorganic trace minerals were added (Figure 1). From the comparison of the data from these two trials, it can be concluded that sows fed diets with Bioplex organic trace minerals or Sel-Plex had higher litter size, but the overall litter size difference between the two trials was not large (Figure 3). It should be pointed out that the management level and facilities used in these two trials were the same, so the differences in the trial results can be attributed more to the effects of the minerals in the sow diet than to the sow management level. Because the breeding industry has generally recognized the situation of mineral loss in sows, a common practice is to feed gestating sows a high-calcium diet. High productivity causes further loss of various mineral reserves in the sow's body (Figure 4). This may be because high levels of calcium in the diet have a negative effect on other trace minerals in the digestive tract (Figure 5). It is well known that calcium can chelate with some other macro minerals (such as phosphorus and sulfur) and some trace minerals (such as iron, zinc and copper), reducing their absorption and bioavailability. In early gestation, because the sow needs less calcium for fetal development than in late gestation or lactation, the levels of dietary calcium and phosphorus can be appropriately adjusted. In each reproductive cycle, the sow's mineral requirements during gestation and lactation do not remain constant.
Figure 3. Effect of the source of trace minerals in the sow diet on litter
size when sows were fed a high-calcium gestation diet in two trials
Figure 4. Loss of body minerals in sows after three parities (compared with non-pregnant sows)
Figure 5. Principles of calcium and phosphorus absorption
Mineral requirements of the fetus
During fetal development, body tissues develop at different rates, and therefore require various nutrients. We analyzed the total mineral content of fetuses from 45 days of gestation to birth. The data show that during the last 14 days of gestation, the sow uses about 50% of the total mineral amount for fetal development (Figure 6). Therefore, the fetus's need for trace minerals from the sow's diet and its own mineral reserves play an important role in the normal development of fetal tissues, especially for the fetus, whose main growth and development stage is in late gestation.
Compared with early development, the pig's requirements for calcium and phosphorus are higher in the last two weeks of gestation. As can be seen from Figure 7, a litter of 12 piglets requires approximately 73 and 44 g of calcium and phosphorus, respectively, during the last two weeks of gestation. Although the fetus's requirement for these macro minerals increases linearly throughout the cycle, the requirement before birth is the most critical. Therefore, the fetus's need for calcium and phosphorus from the sow's body may lead to loss of minerals from the sow's bones during gestation and bone damage.
Figure 6. Total mineral amount of the fetus (45 days of gestation to birth)
Figure 7. Total calcium and phosphorus of the fetus/litter (45 days of gestation to birth)
The developing fetus's requirement for trace minerals from 45 to 114 days of gestation shows a similar trend to the requirement for macro minerals, although the requirement is relatively lower. As shown in the figures, the deposition of iron (Figure 8) and zinc (Figure 9) at different days of gestation, both figures clearly show that the deposition of trace minerals is highest in the last two weeks of gestation, and other trace minerals also show the same trend. These results indicate that pregnant sows have higher trace mineral requirements in late gestation, and compared with sows with low litter size, sows with high litter size have even higher mineral requirements.
Figure 8. Total iron content of the fetus/litter (45 days of gestation to birth)
Figure 9. Total zinc content of the fetus/litter (45 days of gestation to birth)
Mineral requirements of nursery pigs
To meet the needs of the fetus, the sow's mineral requirements are very high in late gestation, but the sow's requirements for these minerals are even higher during lactation. Figure 10 shows that two sows with litter sizes of 11 and 8 piglets require 85 and 68 grams of minerals per day, respectively, to meet the growth needs of the piglets. The calcium requirements of the two litters during the last 10 days of the 21-day lactation period were 19.0 and 13.3 g/day, respectively (Figure 11). During the first 11 days of lactation, the piglets' mineral requirements were relatively high, and the mineral deposition of the two litters was 11.7 and 4.7 g/day, respectively. Therefore, the piglets' mineral requirements increase with lactation or with the sow's milk production. If the calcium or phosphorus requirement is expressed on a per-piglet basis, the calcium and phosphorus contents per piglet in the two litters are similar (unpublished).
Figure 10. Total mineral content per litter of two litters at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
For the contents of various trace minerals in the two litters, please see Figures 12 to 16 in detail. The zinc content shows the same trend as the macro minerals (Figure 12), that is, the larger the litter size, the higher the trace mineral content. However, when the zinc content is converted into daily content, the rate of increase in zinc content is not the same as that of calcium.
Figure 11. Total calcium content per litter of two litters at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
Figure 12. Total zinc content per litter of two litters at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
Although the piglets from the litter of 11 stored more zinc during the first 11 days of lactation, the zinc level was higher than the retention in the last 10 days of lactation. For iron and copper reserves at different stages of lactation, this difference may be even more obvious. During the 21-day lactation period, the daily reserves of iron (Figure 13) and copper (Figure 14) were both higher in the first 11 days than in the last 10 days.
Figure 13. Total iron content per litter of two litters at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
Figure 14. Total copper content per litter of two litters at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
Figure 15. Iron content per piglet at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
Figure 16. Copper content per piglet at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
Conclusion
The mineral levels in the diets of high-producing sows are already higher than the NRC (1998) recommendations. We still need more experimental research on the mineral requirements of sows. Simply increasing mineral levels may be a mistake. For example, research shows that feeding sows a diet containing 0.1% calcium throughout gestation may reduce the number of piglets born per litter. However, it is certain that in late gestation and throughout lactation, the sow's requirements for calcium and phosphorus are increased.
Understanding the trace mineral requirements of breeding sows plays a very key role in improving the reproductive performance of breeding pigs. This study shows that, compared with inorganic salts, the use of organic trace minerals can increase the number of piglets born per litter. It is currently unclear which trace minerals are responsible, but the research results show that the increase in litter size is not solely due to the addition of selenium. Mineral nutrition levels during gestation affect the number of piglets born per litter, but the optimal dietary mineral level is currently unclear. The results of this study indicate that highly prolific sows may not be able to meet the piglets' trace mineral requirements during the 21-day lactation period. Therefore, consider adding higher levels of minerals, but it has not yet been confirmed whether this practice is appropriate.
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The figures and data have not been uploaded.
The original author and translator need to be indicated.
--------------------------------------
The mineral requirements of high-producing sows are still not very clear. Research to date has confirmed that, as parity increases, the sow's body reserves of macro- and trace minerals gradually decline, and high prolificacy further aggravates mineral loss. During the sow's reproductive cycle, there are certain periods, usually late gestation and lactation, when the requirements for macro- and trace minerals are very high. But other periods are equally important. However, simply increasing the macro- and trace mineral content of the sow's diet may not be the ideal approach, because this method may reduce the sow's reproductive performance. Recent research has shown that organic trace minerals can increase litter size after the 6th parity. Research has shown that, although organic selenium has the effect of improving sow reproductive performance, other trace minerals may also play a corresponding role in improving sow reproductive performance.
Effects of trace minerals on sow reproductive performance
Our previous reports showed that when the content of inorganic trace minerals in the diet exceeds the NRC recommended requirement, both the total number of piglets born per litter and the number of piglets born alive per litter in sows decline, but when organic trace minerals are fed (Bioplex series organic trace minerals, Alltech), litter size increases (Figure 1). In addition, when the calcium and phosphorus added to the gestation diet exceed the NRC requirements (1998), the decline in sow reproductive performance is aggravated. The sources of trace minerals in the diet are generally organic trace minerals or inorganic mineral salts (usually in sulfate form). This is based on research on Bioplex organic trace minerals and a study on sow reproductive performance (this study evaluated the efficacy of an organic selenium source - Sel-Plex (Alltech) and an inorganic selenium source - sodium selenite). As shown in Figure 2, the addition of both Sel-Plex and Bioplex organic trace minerals can increase litter size. After adding Bioplex organic trace minerals to the diet, approximately one more piglet per litter can be added, while adding only Sel-Plex can add only about 0.3 piglets per litter. Although these data are not statistically significantly different, numerically, the addition of Bioplex organic trace minerals (including Sel-Plex) is more effective in increasing litter size than the addition of Sel-Plex alone.
Figure 1. Effects of the source and level of trace minerals in the diet on the reproductive performance of sows beyond 6 parities (n=375 litters)
Figure 2. Comparison of the effects of trace mineral sources on sow litter size in two trials
We also conducted another comparison of these studies. In the Sel-Plex trial study by Mahan and Peters (2004) and the Bioplex organic trace mineral study by Peters and Mahan (unpublished), the calcium level contained in the gestation diet was both 1.0%, slightly higher than the NRC (1998) recommendation, but it was comparable to the content in commercial sow gestation diets. In the study by Peters and Mahan (unpublished), compared with sow diets supplemented at the NRC recommended levels (calcium and phosphorus), litter size was lower when Bioplex or inorganic trace minerals were added (Figure 1). From the comparison of the data from these two trials, it can be concluded that sows fed diets with Bioplex organic trace minerals or Sel-Plex had higher litter size, but the overall litter size difference between the two trials was not large (Figure 3). It should be pointed out that the management level and facilities used in these two trials were the same, so the differences in the trial results can be attributed more to the effects of the minerals in the sow diet than to the sow management level. Because the breeding industry has generally recognized the situation of mineral loss in sows, a common practice is to feed gestating sows a high-calcium diet. High productivity causes further loss of various mineral reserves in the sow's body (Figure 4). This may be because high levels of calcium in the diet have a negative effect on other trace minerals in the digestive tract (Figure 5). It is well known that calcium can chelate with some other macro minerals (such as phosphorus and sulfur) and some trace minerals (such as iron, zinc and copper), reducing their absorption and bioavailability. In early gestation, because the sow needs less calcium for fetal development than in late gestation or lactation, the levels of dietary calcium and phosphorus can be appropriately adjusted. In each reproductive cycle, the sow's mineral requirements during gestation and lactation do not remain constant.
Figure 3. Effect of the source of trace minerals in the sow diet on litter
size when sows were fed a high-calcium gestation diet in two trials
Figure 4. Loss of body minerals in sows after three parities (compared with non-pregnant sows)
Figure 5. Principles of calcium and phosphorus absorption
Mineral requirements of the fetus
During fetal development, body tissues develop at different rates, and therefore require various nutrients. We analyzed the total mineral content of fetuses from 45 days of gestation to birth. The data show that during the last 14 days of gestation, the sow uses about 50% of the total mineral amount for fetal development (Figure 6). Therefore, the fetus's need for trace minerals from the sow's diet and its own mineral reserves play an important role in the normal development of fetal tissues, especially for the fetus, whose main growth and development stage is in late gestation.
Compared with early development, the pig's requirements for calcium and phosphorus are higher in the last two weeks of gestation. As can be seen from Figure 7, a litter of 12 piglets requires approximately 73 and 44 g of calcium and phosphorus, respectively, during the last two weeks of gestation. Although the fetus's requirement for these macro minerals increases linearly throughout the cycle, the requirement before birth is the most critical. Therefore, the fetus's need for calcium and phosphorus from the sow's body may lead to loss of minerals from the sow's bones during gestation and bone damage.
Figure 6. Total mineral amount of the fetus (45 days of gestation to birth)
Figure 7. Total calcium and phosphorus of the fetus/litter (45 days of gestation to birth)
The developing fetus's requirement for trace minerals from 45 to 114 days of gestation shows a similar trend to the requirement for macro minerals, although the requirement is relatively lower. As shown in the figures, the deposition of iron (Figure 8) and zinc (Figure 9) at different days of gestation, both figures clearly show that the deposition of trace minerals is highest in the last two weeks of gestation, and other trace minerals also show the same trend. These results indicate that pregnant sows have higher trace mineral requirements in late gestation, and compared with sows with low litter size, sows with high litter size have even higher mineral requirements.
Figure 8. Total iron content of the fetus/litter (45 days of gestation to birth)
Figure 9. Total zinc content of the fetus/litter (45 days of gestation to birth)
Mineral requirements of nursery pigs
To meet the needs of the fetus, the sow's mineral requirements are very high in late gestation, but the sow's requirements for these minerals are even higher during lactation. Figure 10 shows that two sows with litter sizes of 11 and 8 piglets require 85 and 68 grams of minerals per day, respectively, to meet the growth needs of the piglets. The calcium requirements of the two litters during the last 10 days of the 21-day lactation period were 19.0 and 13.3 g/day, respectively (Figure 11). During the first 11 days of lactation, the piglets' mineral requirements were relatively high, and the mineral deposition of the two litters was 11.7 and 4.7 g/day, respectively. Therefore, the piglets' mineral requirements increase with lactation or with the sow's milk production. If the calcium or phosphorus requirement is expressed on a per-piglet basis, the calcium and phosphorus contents per piglet in the two litters are similar (unpublished).
Figure 10. Total mineral content per litter of two litters at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
For the contents of various trace minerals in the two litters, please see Figures 12 to 16 in detail. The zinc content shows the same trend as the macro minerals (Figure 12), that is, the larger the litter size, the higher the trace mineral content. However, when the zinc content is converted into daily content, the rate of increase in zinc content is not the same as that of calcium.
Figure 11. Total calcium content per litter of two litters at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
Figure 12. Total zinc content per litter of two litters at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
Although the piglets from the litter of 11 stored more zinc during the first 11 days of lactation, the zinc level was higher than the retention in the last 10 days of lactation. For iron and copper reserves at different stages of lactation, this difference may be even more obvious. During the 21-day lactation period, the daily reserves of iron (Figure 13) and copper (Figure 14) were both higher in the first 11 days than in the last 10 days.
Figure 13. Total iron content per litter of two litters at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
Figure 14. Total copper content per litter of two litters at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
Figure 15. Iron content per piglet at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
Figure 16. Copper content per piglet at birth, 11 days of age and 21 days of age (litter size 11 vs. litter size 8)
Conclusion
The mineral levels in the diets of high-producing sows are already higher than the NRC (1998) recommendations. We still need more experimental research on the mineral requirements of sows. Simply increasing mineral levels may be a mistake. For example, research shows that feeding sows a diet containing 0.1% calcium throughout gestation may reduce the number of piglets born per litter. However, it is certain that in late gestation and throughout lactation, the sow's requirements for calcium and phosphorus are increased.
Understanding the trace mineral requirements of breeding sows plays a very key role in improving the reproductive performance of breeding pigs. This study shows that, compared with inorganic salts, the use of organic trace minerals can increase the number of piglets born per litter. It is currently unclear which trace minerals are responsible, but the research results show that the increase in litter size is not solely due to the addition of selenium. Mineral nutrition levels during gestation affect the number of piglets born per litter, but the optimal dietary mineral level is currently unclear. The results of this study indicate that highly prolific sows may not be able to meet the piglets' trace mineral requirements during the 21-day lactation period. Therefore, consider adding higher levels of minerals, but it has not yet been confirmed whether this practice is appropriate.
--------------------------------------
The figures and data have not been uploaded.
The original author and translator need to be indicated.