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初產母豬斷奶后不發情、再次配種困難、二胎產仔數降低，是現代母豬生產中最常出現的問題。造成這一問題的根源是進入第2繁殖周期時母豬體營養儲備嚴重不足，因為生殖系統在營養分配的優先權弱于其他器官和系統，故營養缺乏對生殖系統影響最大。當然，初產母豬斷奶不發情也與母豬健康狀況尤其是生殖道健康以及誘情環境相關。下面主要從營養管理著手解決初產母豬斷奶后不發情等一系列繁殖障礙問題。
營養原理與理念
發情所需要的營養儲備，不僅需要大營養儲備，而且也需要生殖營養儲備。大營養儲備主要指淀粉、蛋白質、脂肪、常量礦物質等營養物質的儲備，體現在體重和膘情上面；生殖營養儲備主要指與生殖結構和生殖功能相關的關鍵營養如特殊的維生素、特殊的微量元素等營養的儲備。這兩類營養物資的足夠儲備都是完成繁殖過程不可或缺的。
大營養儲備不足的主要原因有：初產母豬自身增重（初產母豬自身增重約為50kg）、初配不達標、妊娠早中期限飼不夠/不當、日進食營養總量不夠、哺乳期采食量不夠、攻胎不夠。大營養儲備主要目標是：斷奶時，母豬失重不超過10kg，膘情達到體況評分2.5～3分。要實現這一體儲目標，光增加哺乳期采食量是不夠的，需要從初產母豬培育全過程著手（如下圖）。
圖1 泌乳期體重損失對斷奶至發情間隔的影響
生殖營養儲備方面，一要注意限飼期因為精料采食量減少而導致生殖營養攝入不足；二要注意哺乳期的哺乳營養需要與生殖的營養需要是有差異的，在配種準備期，即使飼喂營養相對豐富的哺乳料，也滿足不了發情所需的生殖營養需求；三是還要考慮高溫季節對生殖營養需求的增加；四要考慮環境因素對飼料中生殖營養的破壞；五要考慮商品飼料添加量可能不足。
解決初產母豬斷奶不發情的措施
1）初配要達標。引進的國外品種，初次配種標準要達到：體重140kg以上，背膘18～22mm，日齡230d以上。如果體重輕、背膘薄、年齡未到的母豬過早配種會導致：初產母豬斷奶后發情延遲、再次配種返情率高；二胎窩產仔數少；寒冷季節流產機會增加；泌乳量低，利用年限縮短。
2）初次懷孕母豬，懷孕期的某些營養水平相對于經產母豬而言可以適當提高10%左右，如CP14%，賴氨酸（Lys）0.7%，鈣0.9%，總磷0.8%，有效磷0.45%。
3）初產母豬懷孕后期，仍然需要適度增料攻胎。因為胎兒的2/3的體重是在母豬妊娠期最后1/3的時間增加的，如果不攻胎，根據后代優先的營養分配原理，母豬的營養優先供應胎兒，在攝入不足的情況下，可能動用母豬體脂肪甚至體蛋白來供應胎兒的生長，意味著初產母豬在懷孕后期就在失重和掉膘！再者如果不攻胎，會導致母豬體質下降反而影響分娩；此外，胎兒初生重不足會影響哺乳期仔豬成活率。實際上，調查發現，初生重在1.5kg以內不會因初生重過大而出現難產。
4）鍛煉母豬腸道功能。胃好，胃口才好。這里的“胃好”，指的是胃腸功能好和胃腸道容積大。2014年在歐洲召開的“營養與腸道健康國際學術會議”上，與會專家認為：一是動物的腸道除了消化功能外，還有化學感應和接收機體信號的功能，小腸不僅是被動吸收通道，實際上在吸收之前還有調節控制功能。因此，飼養動物必須先養好小腸；二是對仔豬腹瀉的控制手段，不能僅僅考慮病原的因素，也不要濫用抗生素，而是從改善環境、調整水質和強化營養上下功夫；三是通過母豬的飼喂調控仔豬腸道健康，因此，豬場要把母豬作為核心要素從強化營養和加強管理上下功夫，把母豬奶水調養好；四是在炎熱環境下需要特別注意母豬飼養管理的改善。
懷孕母豬尤其是初產懷孕母豬，在整個懷孕期補充優質粗纖維特別是青綠飼料非常必要，可以減少便秘、鍛煉腸道功能、撐大胃腸容積、促進生殖器官發育、增加母豬幸福指數。試驗研究發現臨產前3d和產后7d補喂青綠飼料，對于減少泌乳障礙、增加7d后的采食量很有幫助。
5）集中豬場優勢資源，增加初產母豬哺乳期采食量。從圖1可以看出，泌乳期體重損失越多，斷奶至發情的時間間隔越長，但這一特征主要在頭胎表現得更明顯（Vesseuret al.,1994）。所以，增加哺乳期采食量是減少初產母豬斷奶掉膘的最有效措施，必須達到理想的采食量目標（kg）：1.8+0.5×（母豬哺乳仔豬數）。
The English version
First farrowing sows after weaning estrus, breeding difficult again, a second litter size is reduced, is most commonly occurs in the production of modern sow. The cause for this problem is to enter 2 nutrient reserves of the sow breeding cycle, because the reproductive system in nutrient allocation priority weaker than other organs and systems, so the nutrient deficiency had the greatest influence on the reproductive system. First-timer sow weaning estrus not, of course, also with the sow health, especially reproductive tract health and induced environment related. Below mainly from nutrition management to address a first-timer sows after weaning estrus problem of a series of reproductive barriers, such as.
Nutrition principles and ideas
Heat needed nutrients reserves, not only need big nutritional reserves, but also need reproductive nutrition reserves. Large nutrient reserves refers to starch, protein, fat, constant minerals and other nutrients reserves, reflect on body weight and body condition; Reproductive nutrition reserve refers to related to reproductive structure and reproductive function of key nutrients such as special vitamins, such as special trace element nutrition reserves. The two kinds of nutrition supplies enough reserves are indispensable to complete reproduction process.
Nutrition are the main reasons of the lack of reserve: first-timer sow weight (first-timer sow weight at about 50 kg), not up to standard, at the beginning of the pregnancy early in the term improper feeding/enough, daily feeding amount not enough nutrition, not enough lactation feed intake, tapping tyres. Nutrition reserve main aim is to: when weaning, sow weightlessness not more than 10 kg, body condition of body condition scoring 2.5 ~ 3 points. To realize the goal of this store, the light is not enough to increase lactation feed intake, the first-timer sow breeding process need to begin (pictured).
Figure 1 lactation weight loss effects on weaning to estrus interval
Reproductive nutrition reserves, one must pay attention to the limited feeding period by a decrease in grain feed intake causes reproductive nutrition deficiency; To pay attention to the nursing nutritional needs of nursing and reproductive have different nutritional needs, in the run-up to mating, even feeding relatively rich nutrition of lactation, also cannot satisfy the requirement of reproductive nutrition for the heat; Three is to consider the high temperature season increased demand for reproductive nutrition; Fourth, we need to consider environmental factors on the feed in reproductive nutrition; Five to consider commodity feed additives may be insufficient.
Solve the first-timer pigs weaned measures are not in heat
1) early to amount to mark. Introduce foreign varieties, breeding standards to achieve: first time more than 140 kg of body weight and backfat 18 ~ 22 mm, more than 230 d day age. If the weight is light, back fat thin, age not to sow breeding early causes: first farrowing sows after weaning estrus delay, high rate of breeding return mood again; Less two nest litter size; Increased opportunities for cold season abortion; Mammary volume is low, use fixed number of year shortened.
2) the first pregnancy sow, some of the nutrition level during pregnancy may be appropriately increased by 10% compared to the multiparity sows, such as CP14 %, 0.7% lysine (Lys), calcium is 0.9%, 0.8% of the total phosphorus, effective phosphorus 0.45%.
3) the first-timer sows late pregnancy, still need to moderate increase is expected to attack. Because two-thirds of fetal weight is increased in pregnancy period finally a third of the time, if you don't attack, according to the principle of offspring priority nutrition distribution, sow nutrition supply priority fetus, in the case of inadequate intake, may use the sow body fat and body protein to supply the growth of the fetus, means a first-timer sows in late pregnancy in weightlessness and DiaoBiao! Moreover if they don't attack, instead, to cause a decline in the sow physique affect delivery; In addition, the lack of fetal birth weight will affect lactation piglet survival rate. In fact, the survey found that the primary emphasis on within 1.5 kg will not occur during childbirth by birth weight is too large.
4) exercise sows the intestinal function. The stomach is good, appetite is good. Here "stomach", refers to the gastrointestinal function and large volume of gastrointestinal tract. Held in Europe in 2014's "nutrition and intestinal health international academic conference", the participating experts believe: one is the animal's gut besides digestive function, as well as chemical sensors and the function of the body's reception, the small intestine is not only the passive absorption channel, actually before absorption and adjust the control function. Animals, therefore, must first raise good small intestine; Second, the control of diarrhea piglets, not only consider the factor of pathogen, also don't abuse of antibiotics, but from the improvement of the environment, adjust the water quality and strengthening nutrition fluctuation kongfu, 3 it is through the sow feeding control piglets intestinal health, therefore, pig farms to sow as core elements from strengthening nutrition and strengthening management, put milk and nurse; Four is in the hot environment need to pay special attention to sow breeding management improvement.
Pregnant sows first-timer pregnant sows, especially in the high quality coarse fiber supplements during pregnancy, especially it is necessary to green feed, can reduce constipation, intestinal function exercise, enlarged gastric volume, promote the development of reproductive organs, increase the sow happiness index. Experimental studies have found that 3 d before labor and postpartum 7 d fill hello green feed, to reduce lactation disorder, increase feed intake after 7 d is very helpful.
5) concentrated pig advantage resources, increase the first-timer sow lactation feed intakes. Can be seen from the figure 1, lactation weight loss, the more weaning to heat the longer the time interval, but this feature is mainly in the first act more obvious (Vesseuret al., 1994). So, increase lactation feed intake is the most effective measures to reduce the first-timer sow weaning DiaoBiao must achieve the ideal intake (kg) : 1.8 + 0.5 x (the sow lactation piglet number).
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