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日期:2019-06-27 阅读:3286次

Do these pants make me look fat?


Obviously, there is never a rightanswer.  It tends to get me in troubleeven if I do answer.


What is the proper Backfat for a sow?  This is one of my most frequent askedquestions.  Fifteen years ago, I had theopportunity to work on a 3-year project studying this question.  I have always been reluctant to answer thisquestion because in general a sow can perform normally with a large range ofbackfat as this project had found out. In differing levels of backfat she will require differing levels ofmanagement.  Fifteen years later the sowis now weaning what we had at that time as total born.  This has made the question of backfat in sowsmore acute today.  You can never be rightin answering this question, but you can see certain levels that are moremanageable.


Generally, sows perform poorly when backfatis taken to extremes.  Sows that are toolean have fertility problems related to metabolizing muscle instead of fatduring the last 3 weeks of gestation when fetus growth is the greatest andduring lactation where the demand for protein (milk) is very great.    Overly fat sows tend not to eat duringlactationand milk offtheir backs (fat reserves). This resulted in excess weight loss, poor subsequent litter size andlong wean to service interval.  Sows thatgain and lose excess of weight during the sow interval will also have a shorterlife span in the herd.  Too skinny sowsmay just not breed back.


So, whatis the right level of backfat?  The rightlevel of backfat is where the sow performs normally without excess loss ofweight during lactation, weans a good litter, breeds back well and stays in theherd for a long time, with the minimum amount of management. 


Backfat is more important in the first 2parities than it is in older sows that have a greater feed intake and largerbody mass to draw from.  Therefore, Iwill focus on the gilt and its development as a best practice.


Maternal gilts should follow a strictgenetic program.  The emphasis on Backfatin maternal gilts should be minimal.  Maternalgilts at 100 Kgs. should be around 12mm to 14mm at 100 Kgs.  Maternal gilts at breeding should be 14mm to16mm.  Maternal gilts at farrowing shouldbe 20mm to 24 mm.  Anything outside thisis acceptable but will require greater management.  I would tend to be fatter with maternal giltsthan leaner.  Backfat has a 40%hereditability and therefore a lean carcass should be focused on the Terminalsire rather than on the Maternal side. Backfat in maternal gilts is interdependent of backfat, age and weightof the maternal gilt.  Charts 1,2 and 3look at these three important interdependent factors.


Here is a chart that gives an idea of where the backfat (in Millimeters) in maternalgilts should range at farrowing.  At breeding shift the chart 4mm to the left.  Ideal at breeding from 16mm to 20mm.


Stop using back fat for milk duringlactation.  The modern sow has 30 % morepigs to wean and weaning 15% heavier piglets. Overall milk for this modern litter requires feed not back fat to getresults.


The second part of this is total bodymass.  Maternal gilts weight is also animportant part of this.  Weight inKilograms at breeding.


The third component is age.  Age in days from birth at breeding.


Here is a look at 5 purebred farms I followin China.  We want to focus on FarmG.  Where they are weaning 13 pigs persow over the last 10 weeks, (12.5 for all last 2 years), with all three breeds Yorkshire, Landrace andDuroc).  It in contrast to the otherfarms, farm G places a great deal of effort in Gilt develop and gilt udderdevelopment.  They focus on getting allthree 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 forthe full term 14 pigs.  Management ofthis gilt is the simplest.  The pre-weanmortality is less than 5%.  Farm H andFarm G have differing strategies.  WhereFarm H puts more pigs on older sows and places less emphasis on giltdevelopment.  Remember your paritydistribution.  The largest group isalways your parity 1 sows.  Farm Gemphasis gilt udder development.  Thishas a great affect in subsequent parities and longevity in the herd.




Backfat is very subjective.  There is a range of acceptable levels.  Some levels are more manageable thanothers.  Backfat in maternal gilts isinterdependent of age and weight.  Maternalgilts require a greater need for backfat management.  Managing Backfat, age and weight of the maternalgilt 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 yourfarm.  Rely on feed intake and nutrientlevels in lactation feed to get milk production.  Do not expect to get results from the sowsbackfat.  I don’t even measure backfatanymore but focus rather on feed intake.




There is no such thing as fat sows anymorein hyper prolific sows.  Only 8.3% areover 24 mm BF.  45% are under 18mm.  These all fall in the manageable to difficultto manage range.  Only 56.7% areideal.  Natural variation is normal.


Natural Variation:


Here isa look at 44 YY gilts in a herd that were Adjusted to 100 Kgs and the backfatwas Adjusted to that 100 Kgs weight.  At 100 Kgs they were from 127 to 139 days of age.  The natural variation of these gilts Back Fatwas from 8.2 mm to 16.9 mm.  These pigsbeing on full feed until they were taken off test and probed to get their truenatural body metabolism of Back Fat.  Noticethe wide range.  The same naturalvariation would be expected at breeding and at farrowing.  The average at 100 Kgs is 12.7 but note thewide variation from that average.  Youcannot use back fat as a true measure of a gilt as an average.  Unless you use its own off test Backfat todetermine where her breeding and farrowing Back fat will be.


Backfat is just anumber, it doesn’t identify performance just the level of management to get herto perform.


Alberta Technology Consultancy(Shanghai) Co. Ltd

Lorne and Vicki Tannas: Swine Production Specialists and Nucleus Support

作者:Lorne和Vicki Tannas:养猪专家为核心场提供专业支持

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