programming and assisted reproductive technologies modules 18 and 19 ans 536 spring 2014

Programming and Programming and Assisted Assisted Reproductive Reproductive TechnologiesTechnologiesModules 18 and 19Modules 18 and 19AnS 536AnS 536Spring 2014Spring 2014

Fetal ProgrammingFetal Programming HypothesisHypothesis

The developing fetus responds to nutritional and The developing fetus responds to nutritional and oxygen shortages by diverting resources from other oxygen shortages by diverting resources from other organs to the brainorgans to the brain

Potential adverse affects may occur later in lifePotential adverse affects may occur later in life Adaptations include:Adaptations include:

Vascular responseVascular response Metabolic responseMetabolic response Endocrine responseEndocrine response

Fetal ProgrammingFetal Programming Exogenous maternal malnutrition during pregnancyExogenous maternal malnutrition during pregnancy

May cause lifelong, persisting adaptation to the fetusMay cause lifelong, persisting adaptation to the fetus Low birth weightLow birth weight ↑ ↑ Cardiovascular riskCardiovascular risk Non-insulin dependent diabetes Non-insulin dependent diabetes

Critical periods of vulnerability to suboptimal Critical periods of vulnerability to suboptimal conditions during developmentconditions during development Vulnerable periods occur at different times for various Vulnerable periods occur at different times for various

tissuestissues Greatest risk: rapidly dividing cellsGreatest risk: rapidly dividing cells

Fetal ProgrammingFetal Programming ‘‘Fetal origins’ hypothesisFetal origins’ hypothesis

Poor Poor in uteroin utero environment induced by maternal environment induced by maternal dietary or placental insufficiency may program dietary or placental insufficiency may program susceptibility later in fetal development and lifesusceptibility later in fetal development and life

‘‘Thrifty phenotype hypothesis’Thrifty phenotype hypothesis’ If If in uteroin utero nutrition is poor, then predictive adaptive nutrition is poor, then predictive adaptive

responses are made by the fetus to maximize responses are made by the fetus to maximize uptake and conservation of any nutrients available, uptake and conservation of any nutrients available, resulting in a conservative metabolismresulting in a conservative metabolism

Problems occur when postnatal diet is adequate and Problems occur when postnatal diet is adequate and plentiful and exceeds the range of predicted plentiful and exceeds the range of predicted adaptive responseadaptive response

Fetal ProgrammingFetal Programming Prevalent in developed and developing Prevalent in developed and developing

countriescountries Dutch famine (limited intake of 1680-3360 kJ)Dutch famine (limited intake of 1680-3360 kJ)

During late gestation was associated with During late gestation was associated with increased adult obesity and glucose intoleranceincreased adult obesity and glucose intolerance

During early gestation resulted in hypertensionDuring early gestation resulted in hypertension Disadvantageous populations in USA, South Disadvantageous populations in USA, South

Africa, the Caribbean, India, and AustraliaAfrica, the Caribbean, India, and Australia Shown cardiovascular risk to be greater in Shown cardiovascular risk to be greater in

populations suffering from poor populations suffering from poor in uteroin utero nutrition nutrition

Fetal ProgrammingFetal Programming Permanent affects of programmingPermanent affects of programming

Modifies susceptibility to diseaseModifies susceptibility to disease Structural changes to organsStructural changes to organs Might pass across generationsMight pass across generations Different effects on males and femalesDifferent effects on males and females

Placental effectsPlacental effects Fetus will attempt to compensate for womb Fetus will attempt to compensate for womb

deficienciesdeficiencies

Metabolic SyndromeMetabolic Syndrome Cluster of abnormalities occurring together, Cluster of abnormalities occurring together,

increase your risk of heart disease, stroke, and increase your risk of heart disease, stroke, and diabetesdiabetes

Largely attributed to altered dietary and Largely attributed to altered dietary and lifestyle factors favoring central obesitylifestyle factors favoring central obesity

Characterized by a group of metabolic risk Characterized by a group of metabolic risk factors in a personfactors in a person Abdominal obesityAbdominal obesity Atherogenic dyslipidemiaAtherogenic dyslipidemia Elevated blood pressureElevated blood pressure Insulin resistanceInsulin resistance Proinflammatory statesProinflammatory states Prothrombotic statesProthrombotic states

Metabolic SyndromeMetabolic Syndrome Abdominal obesityAbdominal obesity

Strongly associated with metabolic Strongly associated with metabolic syndromesyndrome

Atherogenic dyslipidemiaAtherogenic dyslipidemia ↑ ↑ triglycerides, ↓ concentrations of HDL triglycerides, ↓ concentrations of HDL

cholesterol, ↑ remnant lipoproteins, ↑ cholesterol, ↑ remnant lipoproteins, ↑ apolipoprotein B, small LDL particles nad apolipoprotein B, small LDL particles nad small HDL particlessmall HDL particles

Metabolic SyndromeMetabolic Syndrome Elevated blood pressureElevated blood pressure

Strongly associated with obesity Strongly associated with obesity Commonly occurs in insulin-resistant individualsCommonly occurs in insulin-resistant individuals

Insulin resistanceInsulin resistance Commonly associated with metabolic syndromeCommonly associated with metabolic syndrome Usually leads to glucose intolerance Usually leads to glucose intolerance diabetic- diabetic-

level hyperglycemialevel hyperglycemia Independent risk factor for cardiovascular diseaseIndependent risk factor for cardiovascular disease

Metabolic SyndromeMetabolic Syndrome Proinflammatory statesProinflammatory states

↑ ↑ levels of C-reactive proteinlevels of C-reactive protein Excess adipose tissue release inflammatory Excess adipose tissue release inflammatory

cytokinescytokines Multiple mechanisms contribute to inflammatory Multiple mechanisms contribute to inflammatory

statestate Prothrombotic statesProthrombotic states

↑ ↑ Plasma plasminogen activator inhibitor-1Plasma plasminogen activator inhibitor-1 ↑ ↑ fibrinogenfibrinogen

Rises in response to a high cytokine stateRises in response to a high cytokine state Acute phase reactantAcute phase reactant

Proinglammatory and prothrombotic states are Proinglammatory and prothrombotic states are interconnectedinterconnected

Metabolic SyndromeMetabolic Syndrome Underlying risk factors for this condition:Underlying risk factors for this condition:

Abdominal obesityAbdominal obesity Insulin resistanceInsulin resistance Physical inactivityPhysical inactivity AgingAging Hormonal imbalanceHormonal imbalance Genetic predispositionGenetic predisposition Fetal environmentFetal environment

Non-genomic Non-genomic Intergenerational EffectsIntergenerational Effects

Significant evidence that programmed Significant evidence that programmed phenomena can be disturbed in later phenomena can be disturbed in later generationsgenerations Offspring exposed to a poor uterine environmentOffspring exposed to a poor uterine environment Prenatal programming by nutrition or exercise Prenatal programming by nutrition or exercise

(animal models)(animal models) Postnatal programming by nutrition or handling Postnatal programming by nutrition or handling

(animal models)(animal models) Effects:Effects:

Birth weightBirth weight Glucose toleranceGlucose tolerance Hypothalamic-pituitary axis in subsequent generationsHypothalamic-pituitary axis in subsequent generations


Effects on birth weightEffects on birth weight Black and white hooded rats (Steward, 1975)Black and white hooded rats (Steward, 1975) Continued poor maternal nutrition produced amplified Continued poor maternal nutrition produced amplified

effects on birth weight through a number of effects on birth weight through a number of generationsgenerations

Accidental introduction of less-palatable food in control Accidental introduction of less-palatable food in control animals resulted in a period of self-imposed calorie animals resulted in a period of self-imposed calorie restrictionrestriction

Evidence that poor nutrition in one generation can Evidence that poor nutrition in one generation can produce effects on birth weight in subsequent produce effects on birth weight in subsequent generationsgenerations


Effects on birth weight, cont…Effects on birth weight, cont… First generation pups (Pinto and Shetty, 1995)First generation pups (Pinto and Shetty, 1995) Exercise during pregnancy resulted in low birth Exercise during pregnancy resulted in low birth

weigh first generation pupsweigh first generation pups First generation offspring were sedentary during First generation offspring were sedentary during

pregnancy and second generation offspring were pregnancy and second generation offspring were also found to be growth retardedalso found to be growth retarded

Suggesting adverse intergenerational influence of Suggesting adverse intergenerational influence of maternal exercise stress on fetal growthmaternal exercise stress on fetal growth


Metabolic parameters and blood pressureMetabolic parameters and blood pressure Female rabbits with surgically induced Female rabbits with surgically induced

hypertension were mated with normotensive hypertension were mated with normotensive malesmales

Female offspring had increased blood Female offspring had increased blood pressure as adults when compared to the pressure as adults when compared to the offspring of sham-operated femalesoffspring of sham-operated females

Blood pressure in male offspring was Blood pressure in male offspring was unaffectedunaffected


Postnatal effectsPostnatal effects Second generational alterations on glucose Second generational alterations on glucose

homeostasis has been seen when overfeeding homeostasis has been seen when overfeeding takes place in the neonatal periodtakes place in the neonatal period

In rodents, naturally occurring variations in maternal In rodents, naturally occurring variations in maternal behavior is associated with different hypothalamic-behavior is associated with different hypothalamic-pituitary-adrenal stress responsiveness in offspringpituitary-adrenal stress responsiveness in offspring

Postnatal environmental manipulations to the Postnatal environmental manipulations to the hypothalamic-pituitary-adrenal axis stress response hypothalamic-pituitary-adrenal axis stress response may produce intergenerational effectsmay produce intergenerational effects

Assisted Reproductive Assisted Reproductive Technologies (ART)Technologies (ART)

Artificial insemination (AI)Artificial insemination (AI) Sexed semen and embryo sexingSexed semen and embryo sexing Embryo transfer (ET)Embryo transfer (ET) In vitroIn vitro fertilization (IVF) fertilization (IVF) Intracytoplasmic sperm injection (ICSI)Intracytoplasmic sperm injection (ICSI) Gamete intrafallopian transfer (GIFT)Gamete intrafallopian transfer (GIFT) Zygote intrafallopian transfer (ZIFT)Zygote intrafallopian transfer (ZIFT) Donor egg, sperm or embryoDonor egg, sperm or embryo Cloning (SCNT)Cloning (SCNT)

Artificial Insemination Artificial Insemination (AI)(AI)

Used commonly in livestockUsed commonly in livestock Method of banking semen (genetics) without Method of banking semen (genetics) without

keeping a sire on site (cryopreservation)keeping a sire on site (cryopreservation) ChallengesChallenges

Difficulty passing AI gun through cervixDifficulty passing AI gun through cervix Potentially reduced pregnancy ratesPotentially reduced pregnancy rates Breeding when animal is in estrusBreeding when animal is in estrus Damage to reproductive tractDamage to reproductive tract Reduced fertility with cryopreserved spermReduced fertility with cryopreserved sperm

Artificial Insemination Artificial Insemination (AI)(AI)

Management approachesManagement approaches Goal is to increase conception ratesGoal is to increase conception rates Implementing appropriate methods of heat Implementing appropriate methods of heat

detectiondetection Skilled technician in AISkilled technician in AI Time of year, time of day, or temperature on Time of year, time of day, or temperature on

day of breeding can affect conception ratesday of breeding can affect conception rates

Sexed semen and embryo Sexed semen and embryo sexingsexing

Biological mechanismBiological mechanism Sexed semen uses flow cytometry to sort Sexed semen uses flow cytometry to sort

genetically male and female spermgenetically male and female sperm Female (XY) sperm have 4% more DNA than male Female (XY) sperm have 4% more DNA than male

spermsperm Embryo sexing entails obtaining a biopsy of the Embryo sexing entails obtaining a biopsy of the

inner cellular mass (ICM) of the embryo to inner cellular mass (ICM) of the embryo to determine male or female statusdetermine male or female status

Used in livestock industry (dairy cattle)Used in livestock industry (dairy cattle) Ethical considerations in humansEthical considerations in humans


ChallengesChallenges Sexed semenSexed semen

Reduced fertilityReduced fertility Higher concentration of sperm needed to ensure Higher concentration of sperm needed to ensure

pregnancypregnancy Embryo sexingEmbryo sexing

Reduced viability of embryoReduced viability of embryo Multiple pregnancies can occurMultiple pregnancies can occur


Management approachesManagement approaches Sexed semen is preferred method, less risk Sexed semen is preferred method, less risk

to developing embryoto developing embryo Less invasiveLess invasive Sexed semen is used in combination with Sexed semen is used in combination with

IVF technologies or AIIVF technologies or AI Embryo sexing require embryo transfer Embryo sexing require embryo transfer

techniquetechnique

In vitroIn vitro fertilization (IVF) fertilization (IVF) Commonly used practice in humans and Commonly used practice in humans and

livestock (cattle)livestock (cattle) Biological mechanismsBiological mechanisms

Dam is administered a series of reproductive Dam is administered a series of reproductive hormone (GnRH) to stimulate the development of hormone (GnRH) to stimulate the development of Graafian follicles, a.k.a., superovulationGraafian follicles, a.k.a., superovulation

Oocytes are collected via aspiration and are Oocytes are collected via aspiration and are incubated in an artificial lab environment, mimicking incubated in an artificial lab environment, mimicking the environment of the uterusthe environment of the uterus

Sperm is introduced to the oocytes and fertilization Sperm is introduced to the oocytes and fertilization occursoccurs

Embryos are developed to the blastocyst stage prior Embryos are developed to the blastocyst stage prior to transfer to the mother or damto transfer to the mother or dam

In vitroIn vitro fertilization (IVF) fertilization (IVF)

ChallengesChallenges Patients or recipients using IVF technology Patients or recipients using IVF technology

usually face moderate to severe infertility usually face moderate to severe infertility problemsproblems

Poor quality ovum or spermPoor quality ovum or sperm Uterine rejectionUterine rejection May be used as a ‘last ditch effort’ for May be used as a ‘last ditch effort’ for

pregnancypregnancy Incidence of multiple births are highIncidence of multiple births are high Ectopic pregnanciesEctopic pregnancies

In vitroIn vitro fertilization (IVF) fertilization (IVF)

Management approachesManagement approaches Age of the patientAge of the patient

Inversely related to the probability of multiple pregnancies Inversely related to the probability of multiple pregnancies and overall pregnancy successand overall pregnancy success

Implantation rateImplantation rate Attributed to many factors including quality of embryoAttributed to many factors including quality of embryo Selecting embryos with the greatest potential for survivalSelecting embryos with the greatest potential for survival Matching synchrony of uterus to embryo stage of Matching synchrony of uterus to embryo stage of

developmentdevelopment Number of embryos transferredNumber of embryos transferred

Directly related to risk of multiple pregnanciesDirectly related to risk of multiple pregnancies Most controllable of the variablesMost controllable of the variables

Embryo transfer (ET)Embryo transfer (ET) Biological mechanisms (in livestock)Biological mechanisms (in livestock)

A donor animal is super ovulated, bred by a A donor animal is super ovulated, bred by a sire (AI or live cover)sire (AI or live cover)

Fertilization occurs Fertilization occurs in vivo in vivo and embryos are and embryos are collected prior to the implantation stagecollected prior to the implantation stage

Collected embryos can be then be Collected embryos can be then be transferred to a recipient (surrogate) animal transferred to a recipient (surrogate) animal with the same estrus synchrony as the donor with the same estrus synchrony as the donor or can be cryopreserved for a later or can be cryopreserved for a later implantation dateimplantation date

Embryo transfer (ET)Embryo transfer (ET) ChallengesChallenges

Reduced rate of pregnancy as compared to Reduced rate of pregnancy as compared to natural conceptionnatural conception Fresh embryos have better conception rate as Fresh embryos have better conception rate as

compared to cryopreserved embryoscompared to cryopreserved embryos Synchronizing recipient animals with the Synchronizing recipient animals with the

donor animaldonor animal Retained embryos in donor animal resulting Retained embryos in donor animal resulting

in pregnancyin pregnancy

Embryo transfer (ET)Embryo transfer (ET) Management approachesManagement approaches

Optimizing synchrony for maximum Optimizing synchrony for maximum pregnancy ratespregnancy rates

Selecting appropriate recipients for breed Selecting appropriate recipients for breed and birth weight of offspringand birth weight of offspring

Use of prostaglandin in donor animals to Use of prostaglandin in donor animals to eliminate pregnancy due to retained embryoeliminate pregnancy due to retained embryo

Intracytoplasmic sperm Intracytoplasmic sperm injection (ICSI)injection (ICSI)

Biological MechanismBiological Mechanism A single sperm is injected into unfertilized oocyte A single sperm is injected into unfertilized oocyte

and is transferred to a recipientand is transferred to a recipient Treatment for male factor infertilityTreatment for male factor infertility

ChallengesChallenges Potentially abnormal sperm can fertilize ovaPotentially abnormal sperm can fertilize ova Long term health affects, including genetic Long term health affects, including genetic

abnormalitiesabnormalities Lower birth weightLower birth weight Abnormalities on the Y chromosomeAbnormalities on the Y chromosome Greater potential for developmental delaysGreater potential for developmental delays

Intracytoplasmic sperm Intracytoplasmic sperm injection (ICSI)injection (ICSI)

Management approachesManagement approaches Men and women should have genetic Men and women should have genetic

screening for potential chromosomal screening for potential chromosomal abnormalities prior to fertility treatmentabnormalities prior to fertility treatment

Men lacking a vas deferens can carry Men lacking a vas deferens can carry mutations increasing the risk of offspring mutations increasing the risk of offspring with cystic fibrosiswith cystic fibrosis

Gamete Intrafallopian Gamete Intrafallopian transfer (GIFT)transfer (GIFT)

Biological mechanismsBiological mechanisms An unfertilized oocyte and sperm are An unfertilized oocyte and sperm are

combined outside of the uterus and are combined outside of the uterus and are surgically transferred to the site of normal surgically transferred to the site of normal fertilization in the fallopian tube via fertilization in the fallopian tube via laparoscopic techniquelaparoscopic technique

Fertilization occurs Fertilization occurs in vivoin vivo Implantation occurs naturallyImplantation occurs naturally

Gamete Intrafallopian Gamete Intrafallopian transfer (GIFT)transfer (GIFT)

ChallengesChallenges Surgical intervention causes trauma and Surgical intervention causes trauma and

scarringscarring More invasive techniqueMore invasive technique Multiple pregnanciesMultiple pregnancies

Management approachesManagement approaches Other techniques are more widely used Other techniques are more widely used

(IVF) due to higher success rates(IVF) due to higher success rates

Zygote intrafallopian Zygote intrafallopian transfer (ZIFT)transfer (ZIFT)

Biological mechanismsBiological mechanisms Similar to GIFT however, oocyte and sperm Similar to GIFT however, oocyte and sperm

are combined outside of the uterus and are are combined outside of the uterus and are not transferred until an embryo is producednot transferred until an embryo is produced

Management approachesManagement approaches Other techniques are more widely used Other techniques are more widely used

(IVF) due to higher success rates(IVF) due to higher success rates

Donor ova, sperm or Donor ova, sperm or embryoembryo

Donor oocyte, sperm or embryos can be used Donor oocyte, sperm or embryos can be used to generate offspring if poor quality ova or to generate offspring if poor quality ova or sperm exist or if there is a lack of a female or sperm exist or if there is a lack of a female or male counterpartmale counterpart

ChallengesChallenges Social implicationsSocial implications Lack of genetic historyLack of genetic history Predisposition to risk of diseasePredisposition to risk of disease Children may never know their parentsChildren may never know their parents

Cloning (SCNT)Cloning (SCNT)

Producing genetically identical copies of Producing genetically identical copies of a biological entitya biological entity

Different types of methods:Different types of methods: ReproductiveReproductive

Natural identical twinningNatural identical twinning Somatic cell nuclear transfer (SCNT)Somatic cell nuclear transfer (SCNT)

Non-reproductiveNon-reproductive Recombinant DNA TechnologyRecombinant DNA Technology Therapeutic cloningTherapeutic cloning


ChallengesChallenges Low conception ratesLow conception rates Increased birth weightsIncreased birth weights Increased incidence of genetic abnormalitiesIncreased incidence of genetic abnormalities Decreased neonatal survivalDecreased neonatal survival Increased placentation abnormalitiesIncreased placentation abnormalities Decreased life span of animal??Decreased life span of animal?? Increased dystocia and prolonged gestationIncreased dystocia and prolonged gestation Decreased genetic variationDecreased genetic variation


Biological mechanismsBiological mechanisms Low conception ratesLow conception rates

Research is being done to explore this realityResearch is being done to explore this reality Current methods of cloning are very artificial and vastly Current methods of cloning are very artificial and vastly

differ from normal differ from normal in vivoin vivo embryo development embryo development Methods to promote a more similar environment to what Methods to promote a more similar environment to what

the embryo experiences the embryo experiences in vivoin vivo Increased birth weightsIncreased birth weights

Possible link to media used in incubating cloned embryosPossible link to media used in incubating cloned embryos Fetal calf serum (FCS) promotes excessive growth of Fetal calf serum (FCS) promotes excessive growth of

embryoembryo

Cloning (SCNT)Cloning (SCNT) Biological mechanisms, cont…Biological mechanisms, cont…

Increased incidence of genetic abnormalitiesIncreased incidence of genetic abnormalities Possible link to problems in cell reprogramming Possible link to problems in cell reprogramming

with SCNTwith SCNT Electric charge fuses cells to promote cell Electric charge fuses cells to promote cell

proliferationproliferation Decreased neonatal survivalDecreased neonatal survival

Offspring can be less vigorous initially after birthOffspring can be less vigorous initially after birth Anemia, enlarged organs, metabolic Anemia, enlarged organs, metabolic

disturbances, problems thermoregulating, disturbances, problems thermoregulating, hypoxia can all contributehypoxia can all contribute


Increased placentation abnormalitiesIncreased placentation abnormalities Mechanisms unknownMechanisms unknown Hydrops amnion is a condition that is seen during gestation Hydrops amnion is a condition that is seen during gestation

in cattle and sheepin cattle and sheep Less frequent attachment sites but increased size of Less frequent attachment sites but increased size of

codyledons as compared to normal pregnancies in cattlecodyledons as compared to normal pregnancies in cattle Intrauterine Growth Restriction (IUGR)Intrauterine Growth Restriction (IUGR)

Decreased life span of animal ??Decreased life span of animal ?? ““Dolly” the sheep only lived to 6 years of ageDolly” the sheep only lived to 6 years of age Controversial studies that cloning affects life span of Controversial studies that cloning affects life span of

offspringoffspring Decreased telomere length has been associated with a Decreased telomere length has been associated with a

decreased life spandecreased life span Age of animal being cloned may affect life span of offspring Age of animal being cloned may affect life span of offspring

(increased age shortens telomere length) (increased age shortens telomere length)


Increased dystocia and prolonged gestationIncreased dystocia and prolonged gestation Recipient animals carrying cloned animals fail to recognize Recipient animals carrying cloned animals fail to recognize

the onset of parturition near term or the cloned fetus fails to the onset of parturition near term or the cloned fetus fails to induce parturitioninduce parturition

Increased birth weights contribute to dystociaIncreased birth weights contribute to dystocia Decreased genetic variationDecreased genetic variation

Selection of cloned animal can potentially promote a Selection of cloned animal can potentially promote a genetically inferior or superior animalgenetically inferior or superior animal

Breeding pool can be narrowedBreeding pool can be narrowed Long term effects?Long term effects?


Management approachesManagement approaches Low conception ratesLow conception rates

Matching synchrony of recipient animal with Matching synchrony of recipient animal with stage of embryostage of embryo

Increased birth weightsIncreased birth weights Selecting larger framed, multi-parous recipient Selecting larger framed, multi-parous recipient

animals animals Awareness of breed of embryo and potential birth Awareness of breed of embryo and potential birth

weightweight Caesarian section deliveriesCaesarian section deliveries

Cloning (SCNT)Cloning (SCNT) Management approaches, cont…Management approaches, cont…

Increased incidence of genetic abnormalitiesIncreased incidence of genetic abnormalities Humane euthanasia or abortion in severe casesHumane euthanasia or abortion in severe cases Preventing the perpetuation of genetically inferior Preventing the perpetuation of genetically inferior

animals through selectionanimals through selection Decreased neonatal survivalDecreased neonatal survival

Intensive care and monitoring of animal first Intensive care and monitoring of animal first week of lifeweek of life

Ensuring colostrum uptakeEnsuring colostrum uptake Temperature regulationTemperature regulation


Increased placentation abnormalitiesIncreased placentation abnormalities Close monitoring of recipient animals for hydrops Close monitoring of recipient animals for hydrops

amnionamnion Abort early in gestation if necessaryAbort early in gestation if necessary Pregnancy palpations/ultrasound to determine Pregnancy palpations/ultrasound to determine

fetal well beingfetal well being Decreased life span of animal ??Decreased life span of animal ??

Age of animal being cloned may affect life span Age of animal being cloned may affect life span of offspring (increased age shortens telomere of offspring (increased age shortens telomere length) length)


Increased dystocia and prolonged gestationIncreased dystocia and prolonged gestation Know expected parturition datesKnow expected parturition dates Induce parturition if necessaryInduce parturition if necessary Caesarian sectionsCaesarian sections

Decreased genetic variationDecreased genetic variation Criteria for animal selectionCriteria for animal selection Promoting healthy animals – not just based on Promoting healthy animals – not just based on

phenotypephenotype

programming and assisted reproductive technologies modules 18 and 19 ans 536 spring 2014

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