這些褲子讓我看起來胖嗎？　　　　Do these pants make me look fat?　　　　Lorne and Vicki Tannas: 養(yǎng)豬生產(chǎn)專家，核心豬場支持　　　　Lorne and Vicki Tannas: Swine Production Specialists and Nucleus Support　　　　顯然，根本沒有一個正確答案。　　　　母豬的合適背膘厚度是多少？這是我最常問的問題之一。15年前，我有機(jī)會在一個3年項(xiàng)目中研究這個問題。我一直不愿回答這個問題，因?yàn)橐话銇碚f，母豬在較大背膘范圍浮動可以表現(xiàn)正常，正是這個項(xiàng)目得出的結(jié)論。不同水平的背膘厚度，母豬需要不同的管理水平。15年后，我們那時出生總數(shù)的母豬斷奶。這使得今天母豬的背膘問題更加嚴(yán)重。你永遠(yuǎn)不可能正確地回答這個問題，但是你可以看到某些更易于管理的水平?！　　　∫话銇碚f，當(dāng)背膘厚度達(dá)到極限的時候母豬性能表現(xiàn)差。太瘦的母豬存在繁殖性能問題，這與肌肉代謝代替了脂肪代謝相關(guān)，因?yàn)樵谌焉镒詈?周胎兒長得最快，以及哺乳階段機(jī)體對蛋白質(zhì)（乳汁）的需求非常大。過于肥胖的母豬，在泌乳階段往往不吃食，然后乳汁從背部（脂肪儲存）產(chǎn)出。結(jié)果會導(dǎo)致過度丟失體重，后期窩產(chǎn)仔數(shù)少，還有長的斷奶間隔期。在斷奶后間隔期間，增加或丟失過多體重的母豬，也將會在群體中壽命更短。太瘦的母豬可能正好不能飼養(yǎng)回來?！　　　bviously, there is never a right answer.　　　　What is the proper backfat for a sow? This is one of my most frequent asked questions. Fifteen years ago, I had the opportunity to work on a 3-year project studying this question. I have always been reluctant to answer this question because in general, a sow can perform normally with a large range of backfat, as this project had found out. In differing levels of backfat, she will require differing levels of management. Fifteen years later, the sow is now weaning what we had at that time as total born. This has made the question of backfat in sows more acute today. You can never be right in answering this question but you can see certain levels that are more manageable.　　　　Generally, sows perform poorly when backfat is taken to extremes. Sows that are too lean have fertility problems related to metabolizing muscle instead of fat during the last 3 weeks of gestation when fetus growth is the greatest and during lactation, where the demand for protein (milk) is very great. Overly fat sows tend not to eat during lactation and milk off their backs (fat reserves). This resulted in excess weight loss, poor subsequent litter size and long wean to service interval. Sows that gain and lose excess of weight during the sow interval will also have a shorter life span in the herd. Too skinny sows may just not breed back.　　　　那么，正確的背膘厚度是多少呢？正確的背膘厚度是，用最少的管理，母豬表現(xiàn)正常，在哺乳階段沒有額外丟失體重，有好的斷奶仔豬數(shù)量，容易飼養(yǎng)恢復(fù)至正常體重，以及在群體中停留更長的時間。　　　　頭2胎母豬的背膘管理比老母豬更重要，因?yàn)槔夏肛i具有較大的采食量和較大的體重需要調(diào)節(jié)。因此，我將會關(guān)注后備以及將后備母豬的發(fā)育作為一項(xiàng)較佳實(shí)踐?！　　　『髠淠肛i應(yīng)該遵循嚴(yán)格的遺傳程序。對背膘厚度的強(qiáng)調(diào)應(yīng)該降到最低。100kg的繁殖后備母豬背膘厚度應(yīng)該大約在12-14mm之間。進(jìn)入配種階段的后備母豬背膘厚度應(yīng)該在14-16mm之間。分娩階段的后備母豬背膘厚度應(yīng)該在20-24mm之間。在此以外的范圍是可以接受的，但是需要更高的管理水平。我會傾向于后備母豬更胖點(diǎn)而不是更瘦點(diǎn)。背膘厚度具有40%遺傳力，因此應(yīng)該更多地關(guān)注終端公豬而非母系豬。后備母豬的背膘厚度，日齡和體重三者相互關(guān)聯(lián)。圖表1，圖表2和圖表3展現(xiàn)了這三個重要的相互依賴得因素?！　　　o, what is the right level of backfat? The right level of backfat is where the sow performs normally without excess loss of weight during lactation, weans a good litter, breeds back well and stays in the herd for a long time, with the minimum amount of management.　　　　Backfat is more important in the first 2 parities than it is in older sows that have a greater feed intake and larger body mass to draw from. Therefore, I will focus on the gilt and its development as a best practice.　　　　Maternal gilts should follow a strict genetic program. The emphasis on Backfat in maternal gilts should be minimal. Maternal gilts at 100 Kgs should be around 12mm to 14mm. Maternal gilts at breeding should be 14mm to 16mm. Maternal gilts at farrowing should be 20mm to 24 mm. Anything outside this is acceptable but will require greater management. I would tend to be fatter with maternal gilts than leaner. Backfat has a 40% hereditability and therefore should be focused on the Terminal sire rather than on the Maternal side. Backfat in maternal gilts is interdependent of backfat, age and weight. Charts 1, 2 and 3 look at these three important interdependent factors.　　　　下圖給出了后備母豬的背膘厚度（以毫米計(jì)算）在分娩階段應(yīng)該發(fā)生浮動。（在配種階段圖表中厚度增加4mm。配種階段理想的背膘是16-20mm）　　　　Here is a chart that gives an idea of where the backfat (in Millimeters) in maternal gilts should range at farrowing. (At breeding shift the chart 4mm to the left. Ideal at breeding from 16mm to 20mm).　　　　圖表1　　　　　　　第二部分是總體重。繁殖母豬的體重也是一個很重要的組成部分。配種階段的體重公斤　　　　The second part of this is total body mass. Maternal gilts weight is also an important part of this. Weight in Kilograms at breeding.　　　　圖表2　　　　　　第三部分是日齡。配種階段的日齡　　　　The third component is age. Age in days from birth at breeding.　　　　圖表3　　　　　　下面是我在中國跟蹤的5個純種豬場。我們要關(guān)注豬場G。他們豬場過去10周的窩平斷奶達(dá)到13頭（2016年全年是12.5頭），（包括大約克、長白、杜洛克3個品種）。這個豬場同其他豬場形成鮮明對比，他們在后備母豬培育和后備母豬乳房發(fā)育方面做出了很大的努力。他們在培育后備母豬的過程中關(guān)注了所有的三個部分。后備母豬能夠哺乳14頭仔豬。因?yàn)樗哂羞m中的背膘厚度，日齡以及體重，因此有能力全程哺乳14頭仔豬。管理這樣的后備母豬最簡單。斷奶前死亡率低于5%。豬場H和豬場G則有不同的策略。豬場H利用更多的母豬更換老母豬，較少地關(guān)注后備母豬培育。牢記你的胎次分布。最大的群體一直是頭胎母豬。豬場G關(guān)注后備母豬乳房發(fā)育。這樣做會顯著影響隨后的母豬胎次和群體中的使用年限?！　　　ere is a look at 5 purebred farms I follow in China. We want to focus on Farm G. Where they are weaning 13 pigs per sow over the last 10 weeks, (12.5 for all 2016), (with all three breeds Yorkshire, Landrace and Duroc). It in contrast to the other farms places a great deal of effort in Gilt develop and gilt udder development. They focus on getting all three components in developing the gilt. The gilt is given 14 pigs to milk. Because she has adequate backfat, age and weight she is able to milk for the full term 14 pigs. Management of this gilt is the simplest. The pre-wean mortality is less than 5%. Farm H and Farm G have differing strategies. Where Farm H puts more pigs on older sows and places less emphasis on gilt development. Remember your parity distribution. The largest group is always your parity 1 sows. Farm G emphasis gilt udder development. This has a great affect in subsequent parities and longevity in the herd.　　　　圖表4　　　　　　總結(jié)　　　　Summary　　　　背膘厚度是非常主觀的指標(biāo)。它在可接受范圍內(nèi)浮動。某部分背膘厚度區(qū)間比其他區(qū)間更容易控制。后備母豬的背膘厚度跟日齡和體重相關(guān)聯(lián)。后備母豬更加需要進(jìn)行背膘管理。管理后備母豬的背膘，日齡和體重將有助于使母豬的泌乳量最大化，同時延長在群體中的使用壽命。3胎之后差異更加顯著。參考有較好成績的豬場，然后讓較佳實(shí)踐適應(yīng)您的豬場?！　　　ackfat is very subjective. There is a range of acceptable levels. Some levels are more manageable than others. Backfat in maternal gilts is interdependent of age and weight. Maternal gilts require a greater need for backfat management. Managing Backfat, age and weight of the maternal gilt will help to maximize her ability to milk, and have longevity in the herd. After parity 3 the range is much broader. Look at farms with best results and adapt the best practices to your farm.