The productivity of sows is higher than that of primiparous sows. Therefore, the management of breeding farms must focus on keeping the sows in the herds for as long as possible. Therefore, attention should be paid to the daily stages of growth, pregnancy and lactation. The quality and quantity of the feed, ie the energy, fiber, amino acid and protein, vitamins, minerals levels of the feed. The goal of feeding during lactation is to have enough sow to feed your piglets and to prevent excessive weight loss to ensure estrus and breeding as soon as possible after weaning.
1 The energy of lactating sows needs
The daily energy needs during lactation include maintenance needs and lactation needs. The amount of lactation is relatively small at the beginning of the lactation period and peaks around 3 weeks after delivery. The amount required during lactation depends mainly on the number of suckling piglets. Sows first feed their diets to meet their amino acid and energy needs during the lactation period, and then use the body reserves to meet their needs. Sows inevitably lose some body fat even if the lactation period is short. Researchers at the University of Nebraska have shown that sows (53.44 MJ/d), which strictly limit breastfeeding energy intake, are far less likely to estrus during the first 7 days after weaning than energy intake. Double the sow. The same test group later showed that the energy limit to 41.8 MJ/d would have a detrimental effect, but the daily intake increased to 50.16 MJ/d. Koketsu limited the energy intake during the 1st, 2nd and 3rd weeks of lactation to 60%. It was found that the energy intake was limited, no matter what week, the pulse secretion of luteinizing hormone was reduced and prolonged. The interval between weaning and re-estrus. This also indicates that poor feed intake at any time during the lactation period has an adverse effect on subsequent reproductive performance.
In most practical situations, lactating sows cannot eat enough feed to meet their energy needs, so weight loss usually occurs during lactation. In general, the lack of energy and weight loss in primiparous sows are usually extremely significant. There is a lot of evidence that the extreme reduction in stored fat can hinder the sow's cycle estrus. From the production experience of commercial pigs, the degree of body fat loss is an important factor in the low reproductive efficiency of many sows, but there is no experimental evidence. A negative balance of energy does not immediately affect the sow's lactation and the growth of the piglets, as the sow has sufficient reserves to supplement the feed energy. However, if there are repeated energy supply problems for several consecutive births, sow lactation and piglet growth will be affected. Therefore, in order to prevent this from happening, measures should be taken from the first and second births. The best solution is to increase the nutrient concentration of the diet or increase the feed intake of lactating sows so that the sows can feed up on average during lactation. More than 7kg.
The application of fat in lactating sow diets is based on the high energy requirements of lactating sows, and the addition of high energy concentrations of fat can increase the energy concentration of the diet and the energy intake of the sow. The use of fat can also reduce the effects of body heat gain and reduce the side effects of high temperature stress on sow production. The use of fat can increase the energy level of the diet, reduce the weight loss of the sow, increase the fat content of the milk, and increase the survival rate of the light-weight piglets. However, the fat addition of more than 5% will reduce the reproductive performance of the sows and increase the feed cost. store.
Expanded soybeans are of great help to improve the lactation capacity of sows. The amount used in mammals should not exceed 30%. Otherwise, the sows may have estrus during lactation, resulting in abnormal estrus after weaning. It affects the production rules of pigs and causes greater economic losses. In addition, intensively farmed sows have special needs for essential fatty acids. Currently, linoleic acid and arachidonic acid are more important. The recommended addition amounts are not less than 7g/kg and 5g/kg, respectively.
2 The protein and amino acids of lactating sows need
Proteins and amino acids are extremely important for suckling sows. Amino acids are required for lactation and maintenance of lactating sows. Up to one-third of the weight loss during sow lactation is a reduction in muscle tissue. The body decomposes proteins in muscle tissue to provide the amino acids needed for lactation. It is much more difficult to compensate for lean meat loss in the next breeding cycle than to compensate for fat loss.
Keeping the minimum body protein loss ratio requires a higher level of lysine intake (49 g/d) because sows can use body proteins to meet lactation needs. Touchette (1996) also confirmed the same conclusion. This loss of protein affects the reproductive performance of the sow in the future.
It has been reported that the loss of body protein from 5kg to 0 during lactation shortens the interval from weaning to estrus from more than 20 days to less than 10 days. The lysine intake of lactating sows also has an important effect on subsequent reproductive performance. The lysine level of the primiparous sow lactation diet increased from 0.62% to 1.5%, and the number of litters in the next litter increased from 10 to 11. During the first lactation period, lysine intake above 58g/d increased the litter size of the second litter from 9.6 to 10.7 compared to the lysine intake below 37g/d. . Based on regression statistics on published lysine intake and litter weight gain, 26 g lysine per kilogram of litter weight per day is required. Dourmad studies have shown that lactating primiparous sows have a digestible lysine utilization capacity of up to 48 g/d (58 g/d total lysine), thereby minimizing loss of body protein; when digestible lysine When the acid level is below 48g/d, the sow uses a lot of protein to maintain milk production. According to Touchette, in order to increase the number of litters in the next litter, the sow should consume at least 52 g/d of lysine during lactation, mainly because the intake of lysine is higher than the level required to increase milk production. Reduce nitrogen loss, thereby increasing litter size in subsequent litters. In addition, the level of lysine in the diet has an interaction with energy.
Tokach reported that lysine and digestible energy intake during lactation have an interaction with the amount of components in the milk. In order to increase milk production, the amount of lysine required increases with the increase in digestible energy intake. Therefore, the level of lysine should be increased in the preparation of high-energy breastfeeding diets.
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