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1、Swine Breeding,Genetics and Reproduction,Dr.Randy Harp,The Stress Report,Meat quality is the key to what we are sellingPackers figure out how to identify poor quality and where it comes fromPackers are pushing to get leaner hogs,yet not with poor qualityPorcine Stress Syndrome(PSS),Two types of PSS
2、genes,Napole(RN)and Halothane(HAL)RN is a dominant allele(RN-)and a recessive allele(rn+)that is simply inherited on one locusThe RN-reduces the ultimate pH of the muscle that reduces WHC and increases purge esp.in the ham and loin,PSS cont.,HAL-is a mutation on chromosome 6 of the pig at nucleotide
3、 1843.It increases lean meat content but enhances PSE and PSS.PSS animal lacks the ability to adapt to stressHAL is inherited also from a single locus and there are two alleles(N normal and n mutant),PSS cont.,HAL has three possibilitiesNN normalNn carriernn mutant(stress positive)DNA probe now can
4、identify all three genotypes 30-50%of carriers will produce inferior muscle pork quality,Pork Quality,All poor pork quality is not due to HAL only-about 20%of poor pork quality was negative for HALYet,eliminating HAL positive pigs would drastically help the pork quality issues,PSS-genetic influence,
5、worst condition is homozygous recessive for HAL and RNproduces carcasses that are watery,chewy and undesirablethey reproduce at lower rates and often die before they get into the breeding herdheterozygous-dont show signs but carry the potential for stress,PSS,either homoz.or heteroz.will cause probl
6、ems either in transit or at the packing plantLauren Christian of Iowa State says to mate the carrier sows to totally free boarsif you have any stress genes in the herd,look at them as though they are strictly terminal(yet try to stay away from it),PSS,Nebraska SPF claims that they were the first to
7、have stress free herdsAmerican Yorkshire Club first to take a stand against the stress geneany York boar used for AI or natural had to be test by DNA test and be free in order to be registeredDuroc&Chester White Associations were second and third to pass similar rules,Birth Defects,estimated one out
8、 of one hundred has some birth defectaround 150 different known birth defectsonly 13%are known to be due to geneticsabout 13%due to environmental effectstherefore,75%unknown,if problems pop up,ask four questions:,were the defective pigs sired by the same boardoes the condition trace back to one sire
9、,if every litter was effectedare the matings due to abnormal inbreedingwere the dams afflicted treated similarly during gestation,Abnormalties,PSSScrotal Hernia-result from weak muscles around the scrotumfrequently occurs at castration recessive gene action is probable causeUmbilical Hernia-belly ru
10、ptures or belly busts,Abnormalties,Atresia Ani-pigs born without an anusgilts can survive,but boars dieChriptorchidism-Males with one or both testicles retained in the body cavity and the animal is sterileHermaphrodites-intersexuality among European breedsUnderline defects-pin,inverted or blind nipp
11、les,Abnormalities,Tremors-shakers,trembles,myoclonia congenital,shivers,jumpy pig diseaseFour types of tremorsnon-heritable:caused by infection of certain hog cholera strains and shows small brains and spinal cordsnon-heritable-pre-birth infection by a virus such as PRVtwo type of heritable-recessiv
12、e gene action with specific breeds,Abnormalities,Leg defects:splayleg or spraddle legs-usually rear legs affectedtruly unknown,but causes considered are choline deficiency,viral infection,etc.small inside toesbent legs,Leg Defects cont.,polydactyly-mulefoot(presence of only one toe per foot caused b
13、y single dominant gene)thickened forelimbs-connective tissue replaces muscleNon-leg defects:Blood Warts-moles or skin tumorsBrain hernia-generally lethal,Abnormalities,Humpback-crooked spineHemophilia(bleeders)-mycotoxins caused and by recessive inheritanceRectal prolapse-no genetic influence(caused
14、 by environ.such as coughing,piling,feed ingredients,antibiotics and diarrhea),Principles of Swine Breeding and Selection,Swine testing programsproduction testing at central test stations or on the farmPerformance testing-testing of the individualProgeny testing-testing of the offspringPedigree sele
15、ction-using the reputation or records of animals for breeding selection,Possible economic important traits for selection,feed efficiencylitter size weaned%lean cuts or cutabilityconception rate21 day litter weightsoundness scoreave.daily gain,Types of Breeding,Crossbreeding:the mating of animals of
16、different breeds.Outcrossing:the mating of relatively unrelated animals within the same breed.,Types of Breeding cont.,Inbreeding:production of offspring from parents more closely related than the average of a population.Line breeding:a form of inbreeding in which an attempt is made to concentrate t
17、he inheritance of some ancestor in the pedigree.,Principles of Swine Breeding and Selection,Breeding Program-a designed system of management to make genetic improvementBasic stepsestablish goalsdetermine economic traitsutilize recordsevaluate performancestick to your program,Principles of Swine Bree
18、ding and Selection,Factors that determine to include in a selection programeonomic valueheritabilitygenetic relationship with other traitsease of measuring,Heritability Estimate,Heritability estimate:hereditary variation due to additive gene action.effects the rate of improvementlow heritability len
19、ds to slow rates of improvementhigh heritability estimates yields faster rates of improvement,Heritability Estimates for economical important traits,Rate of Gain-days to 23035%Feed Efficiency30%Litter size15%Loin eye Area50%,Ave.Daily Gain40%Litter Weaning Wt.15%Carcass length60%Backfat 40%,Terminol
20、ogy,Prepotency:the amount that an offspring looks like the parent.Nicking:when genes of the dam and sire complement each other.Heterosis:the improvement that the offspring has over its parents.,Selection Systems,Tandem-looking at intensifying on one trait at a timeIndependent Culling-using minimal c
21、riteria to select for two or more economic important traitsSelection Index-using the combination of two or more economic important traits by observing an index to make selections for breeding,Selection Differential,definition-the difference between animals selected to be parents and the average of a
22、ll animals in the herd for selection for a specific traitS.D.=ave.of animals selected minus the ave.of all animals X heritability,Example of selection differential for Feed Efficiency,selected females-2.9 and males at 3.1#of feed/#of gainave.of parents=3.0,herd ave.was 3.3diff.is.3,whereas heritabli
23、ty=.35therefore,.3 X.35=.105 gain from selection$?40-240#=200#gain=600#of feed,Expected Progeny Differences-EPDs,a prediction of the progeny performance of an animal compared to the progeny of an average animal in the population,based on all information currently available.do not cross comparehandou
24、t from Duroc Swine Registry,Swine Reproductive Anatomy&Physiology,REPRODUCTION DEFINITIONS,Organ-any part of the body having a special functionGland-an organ that produces a specific productEndocrine-a gland that secretes discharges directly into the bloodExocrine-a gland which discharges its secret
25、ions through a duct,Reproductive Function&Hormones in the female are influenced in response to:,Season,Genetics,Nutrition,Body Condition,Lactation Length,Parity,Housing,Management,Stress,Disease,Age,Reproduction Depends Upon Hormonal Interaction and Responses:,Reproduction in Female Pigs is Cyclic,E
26、strus,Estrus,Estrus,Estrous Cycle,The Hypothalamus Secretes GnRH(Gonadotropin Releasing Hormone)in response to:,Season,Genetics,Nutrition,Age&Weight,The Pituitary,Secretes gonadotropins in response to GnRHFSH Follicle Stimulating HormoneLH Luteinizing HormoneSource of OXYTOCIN(PG600 like),Reproducti
27、on Depends Upon Hormones:,GnRH,LH&FSH,Reproductive Hormones,Estrus,Progesterone Prevents estrus,Estrogen Induces estrus),LH Causes ovulation,The Reproductive Tract,Bladder,Oviduct,Vulva,Vagina,Cervix,Uterus,Ovary,Swine Female Repro Tract,The Vagina,The organ for copulation(mating)pH unfavorable to s
28、permµbes,The Cervix,Mucus sourcehas 5 interdigitating padsprotects fetus when closed,The Uterus,the site of embryo and fetal developmentProstaglandin production,prostaglandins,The Oviducts,catch egg site of fertilizationleads to uterus,The Ovary,Has numerous follicles-which contain eggs&hormone
29、s,Tract Comparisons,Embryonic Position in the Uterine Horns,Reproductive Function&Hormones in the boar are influenced in response to:,Season,Genetics,Nutrition,Body Condition,Housing,Management,Stress,Disease,Age,Hypothalamus Gland,GnRH,Pituitary Gland,FSH&LH,The Pituitary responds to GnRH productio
30、n,Testes,FSH&LH,The testes respond to FSH&LH presence by beginningspermatogenesis.,Reproduction Depends Upon Hormonal Interaction and Responses:,Male Hormone Production,Androgens,Testosterone,EstrogensIngibins,The Hypothalamus Secretes GnRH(Gonadotropin Releasing Hormone)in response to:,Season,Genet
31、ics,Nutrition,Age&Weight,Boar Exposure Maturity Required,Boars should beReasonably aggressiveVocalActive secondary sex glandssub maxillary salivary glandspheromones,MALE ANATOMY,Testicles-primary sex organproduces sperm cells(spermatogenesis)Scrotum-regulates temperature of the testicles(tunical dar
32、tos muscle)Paniform plexus-network of arteries and veins to provide blood supply of the testicleslocated above the testicle within the spermatic cord,MALE ANATOMY,Cryptorchidism-one or both testicle that do not descend into the scrotum during embryonic developmentEpididymis-four functions for sperm
33、cellstransportstoragematurationconcentration,MALE ANATOMY,Seminiferous tubules-within the testicleplace where sperm cells are formedVas deferens-function is to transport spermatozoa to the urethraPenis and urethra-transport spermatozoa to the female for natural insemination,SEMEN,Criteriamotility pe
34、rcentage of abnormal spermvolume,FEMALE ANATOMY,Ovaries-primary sex organproduces the female reproductive cell“the egg”process of oogenesisunlike the male,it is not continuouscontrolled by the estrus cycleproduces a primary follicleGraafian follicle:mature follicle,FEMALE ANATOMY,Ovulation:when the
35、tissue ruptures and releases the eggCorpus luteum-cells that grow rapidly replacing the blood clot from the ruptureplays an integral role in pregnancy detection by the body,FEMALE ANATOMY,SECONDARY SEX ORGANSreceives the semen and transports the sperm to the egginfundibulumoviduct(fallopian tube)ute
36、rine hornsuteruscervixvagina,FEMALE ANATOMY,Infundibulum-catches the released eggFallopian tube-place where fertilization occurs important that sperm is at the upper end when ovulation takes placeUterine Horns-where the embryo develops in cattle,sheep,and swine before attachment,FEMALE ANATOMY,Uteru
37、s-major body of storage for the fetusfetus develops within the uterus within a layer of membranes called the placentaCervix-overlapping and interlocking folds that form the so-called neck of the uteruspassageway for spermprotection from infection during pregnancyVagina-receptacle for male for servic
38、e,HORMONAL CONTROL,MALETESTOSTERONE-secreted by the testicleresponsible for development and maintenance of the male reproductive tractsex driveincreases muscular and skeletal growthessential for sperm formationdevelopment of secondary sex characteristics,HORMONAL CONTROL,MALEInfluenced by the anteri
39、or lobe of the pituitary glandGonadotrophic hormones that affect the maleFSH(follicle stimulating hormone)development of seminiferous tubules and sperm cellsLH(luteinizing hormone)influences interstitual cells to secrete testosterone,HORMONAL CONTROL,FEMALEEstradiol:produced by the Graafian follicle
40、Estrogen:a collective term for a number of hormones similar to estradiolFunctions:development of secondary sex organsonset of estrus(heat cycle)affects rate and type of growth as well as deposition of fat,HORMONAL CONTROL,FEMALEPROGESTERONEhormone of pregnancysuppresses production of follicles and e
41、strogenprepares the uterus to receive the fertilized egg,HORMONAL CONTROL,FEMALEHORMONESFSH-stimulates growth of the follicleLH-causes rupture of the follicleLTH(lactogenic hormone)-milk secretionLH(luteotropic hormone)-formation and maintenance of the corpus luteum(CL),BREEDING AND REPRODUCTION,Rep
42、roduction efficiency is most important economic important trait,REPRODUCTION,Puberty 4-7 monthsGestation 114 days(3x3x3)Breed to farrow than 1 year of age or breed at least 225 lbs.Natural vs A.I.adv:extension of semen,decrease disease spreading,Heat Period,Standing Heat(2-3 days)Ovulations usually
43、occurs 2nd day of heatswine should be bred at ovulation1st mating of gilts should be on the 1st day1st mating of sows should be on the 2nd dayeach should be re-bred 12 to 24 hours latercycle=18 to 24 days ave.21,Swine Fertility,average-releases 18-25 eggsfertilizes 14-18birth 8-14wean 8Breed,nutriti
44、on and disease dependent,Flushing the Sow,increase grain or concentrate in the diettwo weeks prior to breedingincrease eggs ovulatedhowever,if over-conditioned,lightly exercise gilts for 2-4 weeks before breeding,Breeding after farrowing,standing heat occurs 3-10 days after weaningusually breed sows
45、 2nd day after heat detectioncommercial vs purebredbreed 1st vs 2nd heat cycle,Reproduction Facts,The effect of increased dietary protein and energy can increase gilt mammary tissue slightly,coupled with lipid content in the mammary glandsMany cases of mature sows or just weaned sows may deplete the
46、ir Vit E reserves as they age and while they are nursingHigh producing sows have higher nutrient requirements,Repro Facts,gilts in confinement are slower to reach puberty and show estruskeep gilts grouped together without overcrowdingprovide exposure to boars for teasingreplacement gilts are usually
47、 kept separate at the end of the finishing floor and then moved to the gestation barn at around 6.5 months of age,Repro Facts,station an old boar(because of stronger boar smell)near the gilt penHave a sprinkler system in the summertime Use lighting in confinement situations to simulate outdoorsProvi
48、de 16 hours of artificial lighting at 1/2 watt per sq.ft.,esp.in the fall for breeding,More Repro Facts,Yugoslavian research indicates that sows are safely pregnant after 42 daysTherefore,it may help to continue to provide boar exposure for 45 days post-breedingAny unusual change in the environment
49、will create estrusPoor ventilation-20 ppm of ammonia will decrease estrus,Dont let them stop cycling,seasonalfeed intake-not enough protein or energy during lactation decreases estrus at weaningfirst litter sows are later than older sowsfeeding in gestation-too much can cause more anestrous at weani
50、nglitter size?combined with nutrient req.and feed intake,Detecting heat,sows ave.5 days after weaningsplit weaning helps-wean half the litter 2 days before resulting sows in standing heat soonersigns-swollen and reddening of the vulva,mounting,etc.handout,Synchronizing Estrus,PMS/HCG(PG 600)75%effec
