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猪的营养与饲养

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2025-01-04 00:52

Animal Nutrition HandbookSection 11:Pig Nutrition and FeedingPage 285Copyright 2009 by Lee I.ChibaPIG NUTRITION AND FEEDINGCReferences:Chiba(2004;http:/www.ag.auburn.edu/lchiba/swineproduction.html)&NRC(1998).Also,see Chiba(2000)in Theodorou and France(2000).REPLACEMENT BOARS AND GILTS1.Replacement BoarsA.Some considerations:1)Consider buying a strong boar in a good body condition(including sound feet andlegs)from a reliable seedstock producer(.known genetics and herd health)-Selection should be based on the performance record rather than placing too muchemphasis on how they look.2)Purchase boars(5.5 to 6 mo.old)at least 60 days before being used-Should notuse boars before they are 7.5 to 8 mo.old.3)Isolation-Isolate all new boars a minimum of 28 days for treatment for parasites,vaccinations,acquisition of immunity for microorganisms on the farm,andevaluation of sexual behavior(&possibly semen too).4)In the confinement system,a boar should be housed individually,and provide 35 to50 ft2/pen or use 28 in.x 7 ft.stalls.5)In non-confinement system,should have 20 ft2 of shelter and dry sleeping area.Better to house boars individually,but if not possible then:a)boars must be rearedtogether,and b)should provide 20-24 of feed space/boar,and one waterer/3boars.B.How should we feed?1)The newly purchased boar has less appetite for the first few days because of thechanges in the environment and other factors,thus,may want to obtain a bag offeed from a supplier!2).Feed sparingly,i.e.,feed.2 lb the first day and increase gradually,and feed tomaintain a proper body condition,which can be done by feeding 4 lb/day.2.Replacement GiltsA.Some considerations:1)Selecting gilts?a)At birth-Ear notch at least twice as many gilts as will be needed,and keeprecords,and may want to foster barrows in large litters(.does not mean thatgilts should be selected from small litters though!).b)At weaning-Remove gilts from a list if their sows did not milk well.Animal Nutrition HandbookSection 11:Pig Nutrition and FeedingPage 286Copyright 2009 by Lee I.Chibac)Finishing phase-Make a final selection at 175 to 200 lb based on growth rate,backfat,mammary&skeletal systems and vulva development.2)Early pubertya)Most gilts reach puberty at 6-8 mo of age(avg.,.200-220 days)-Theyshould reach puberty(1st estrus and ovulation)at an early age.b)Gilts should express one or more estrous cycles before the breeding age(7-9mo)because may be able to increase.2 pigs/litter by breeding at 2nd estrusvs.1st estrus!c)Factors affecting puberty?-Genetics,season of the year(winter-and spring-born gilts tend to have delayed expression of the 1st estrus),confinement,etc.3)Stimulate gilts or induce estrus?a)Stimulation should precede the breeding period by 3 to 4 wk.b)Regrouping and relocation:(1)Gilts should weigh.200 to 230 lb(5-5 to 6 mo of age),and startrestricting energy intake by feeding 5-6 lb/day.(2)If possible,relocate to the outside.Relocation seems to be the mostimportant component of transport phenomenon,and relocation within theconfinement is less effective vs.moving to the outside.c)Perhaps,use PMSG(Pregnant Mare Serum Gonadotropin-similar to FSH)and HCG(Human Chorionic Gonadotropin-similar to LH)to induce estrus ingilts that have not cycled.d)Allow a fence-line contact/supervised direct mingling with a sexually active,mature boar for 15-30 min/day.Check gilts for estrus with the main criterionbeing a standing reaction to the pressure applied to the back with the presenceof a boar.B.How should we feed?1)Most gilts are developed to 175-200 lb by self-feeding grower-finisher diets.2)Should restrict energy intake after 175-200 lb,which can save feed costs and avoidunneeded weight gain to avoid a reduction in the longevity and unsoundnessproblems!3)Restrict the energy intake by hand feeding 5-6 lb of balanced diet/day.Shouldadjust feed allowance because:a)require 10%less feed(.0.5 lb less/day)in theconfinement,and b)require 25%more feed(.1 lb more/day)during the coldweather.4)Flushing or high-energy feeding-End restricted-feeding and increase feed intakeby 50 to 100%7-10 days before breeding,which can maximize the ovulation rate!Animal Nutrition HandbookSection 11:Pig Nutrition and FeedingPage 287Copyright 2009 by Lee I.Chiba5)A practical feeding approach?:a)Feed a grower diet until making a final selectionat 175-200 lb,and,then,b)feed a lactation diet(5-6 lb/day)thereafter?BOARS AND SOWS AT BREEDING1.Feeding Boars?A.When to feed?1)They have a tendency to stop and eat spilled feed in the alley and miss sows in astanding reaction because of the delay!2)Thus,boars should be fed before being used in the hand mating system.B.How much?1)Before the breeding period(within 2 weeks),feed 5-6 lb of a well-balanced 14%CP diet to young boars and 4-5 lb to older boars in a good body condition.2)During the breeding period?-Depends onthe work load,but increase the amountsome?3)After the breeding period?-Depends on abody condition and the idle period,butgenerally 4 lb of a well-