Bovine Repro Final Flashcards
historical procedure for embryo transfer
full surgery with vets/techs/anesthesiologists etc. there is a middle incision and flank incision to flush into large container (container can hold lot of fluid so there is a lot to sort through to find) –> later made filter
then to transfer gun needs to make it into uterine horn so embryo can shot out front or sides and need to make sure it is in the side of the horn with CL (use palpation)
what is the embryo transfer filter
plastic embryo collection filter with 70 micron stainless steel filter
lid with in-flow connection, vent cup lid etc
embryo transfer (finding oocyte)
need stereomicroscope (10-50x suitable for bovine repro embryology
factors affecting success for ET
- time in holding medium: at 2 - 7hrs can have almost 6,000 transfers with 73% preg vs 19 - 24hrs can have 150 transfers and 72% preg
- embryo age day of flush: best to flush cows day 7 but 6 and 8 have no statistical difference
- using invivo vs invitro
- fresh > frozen
scales for grading embryos
IETS 1 - 4 (international embryo transfer society)
1 = excellent/good 2 = fair 3 = poor 4 = degenerate
want to have 1 or 2 (2 has 63% pr vs 3 has 46% pr)
embryo transfer recipient-donor estrus synchrony
increased percent pregnant at 24hrs on both ends (plus/minus) when being synched
sever decrease if using frozen embryos 24hrs after synching
embryo transfer on-farm factors (4)
management
synchronization of donors
nutrition
seasonal effects
invivo vs invitro (ET)
invivo: day 0 is the time you detect first standing heat, embryos are less advanced, should be within 24hr synch
invitro: day 0 is considered maturation, embryos have blastocysts and expanded blastocysts
vitro uses more matured egg
new tools
new/greatly improved tools appear constantly, about every 7 years truly novel tool occur which revolutionize science and application
1/2 noble prizes in physiology or medicine concern new tools
superovulation
neew tech to superovulate cows and collect much more embryos per flush, about 60% use FSH about twice daily for 3 to 4 days
cryopreservation of embryos
allow movement of valuable genetics, no need for large recipient herd, preserve genetics from deceased animals, can be coupled with other technologies (embryo biopsy)
gly (glycerol) eg (??)
revolutionary tools (5) ET
transgenic technology, stem cell biology, somatic cell nuclear transplantation, polymerase chain reaction, fertilization by sperm injection
IVF history
1959 first to be done in mammal being a rabbit
1981 first calf from IVF
1988 1st repeatable OPU (ovum pick up) protocol
1990s production of calves from IVF commercially established internationally
IVD (in vivo derived) trends decrease and IVP (in vitro produced) trends increase
IVP vs IVD
IVD = in vivo derived
IVP = in vitro produced
IVP > IVD trending
source of oocytes
OPU = ovum pick-up or transvaginal oocyte aspiration
slaughterhouse/deceased animals
why surge in IVF embryo production?
advances in collection, handling, processing, storage, transport, transfer
improved equipment for OPU and improvement in super stimulation protocols
more in dairy breeds but increasing overall, can leave embryo out for 24 hr and won’t see decrease in preg rate vs oocyte need to be more careful with temp
collecting oocyte process
oocytes are sensitive to temperature, move oocytes into an incubator as quickly as possible, grading for oocytes
storage = slow rate freezing?, vitrification = freezing so quickly liquid doesn’t form ice but instead glass-like solid, improvement in media
transport = portable incubators, maturation during shipment, shipping media does not require equilibrium
steps in in vitro embryo poduction (3)
- maturation
- fertilization
- embryo culture
fertilization: AI 2 mil put in for semen, usually get about 100 sperm trying to fertilize egg, capacitation that change sperm plasma membrane, chose frozen over fresh for invitro
maturation in vitro vs in vivo
in vivo = final maturation due to LH surge in vivo, cAMP maintains meiotic arrest by inhibiting PDE3, LH surge -> decrease cAMP -> releases inhibition of PDE3 -> resumption of meiosis
invitro = final maturation due to removal from an inhibitory environment, removal from inhibitory environment initiates maturation
capacitation
requires changes in the sperm plasma membrane so sperm is able to penetrate and fertilize the egg, sperm aquire the ability to fertilize oocytes (acromse reaction, hyperactivated motility) cryopreservation of sperm facilities capacitation
methods of inducing capacitation in vitro
heparin = binds to proteins that stimulate loss of membrane cholesterol and phospholipids increase Ca acrosome
caffeine = increase cAMP
BSA = removes cholesterol from membrane
freeze/thaw sperm = destabilizes membrane
ICSI
intracytoplasmic sperm injection\
dont usually do/does work well for bovine but will use when sperm are less mobile or don’t swim well
culture systems ET media
1 vs 2 vs 3 step media
composition of media is important: energy substrates, buffers, amino acids, antioxidants, macromolecules, osmolytes
why use IVF
females that process abnormalities in their reproductive tracts, terminal females, improves efficiency of sperm if semen is rare or expensive, can aspirate oocytes during the first 90 days of pregnancy
in vitro vs in vivo produced embryos
in vitro-produced embryos are inferior higher preg rate but more loss! b/c embryo quaity , lower preg rates, some suggestion of epigenetic problems
as culture systems improve the gap may lessen
IETS grade description
grade 1 = 3+ complete layers of cumulus
grade 2 = 1-2 compete layers of cumulus
grade 3 = <1 complete layer of cumulus
grade 4 = expanded cumulus
current use in industry for IVF
on the rise, specialized centers for IVF production, veterinarians performing OPU, embryos exported around the world
zygote development
zona pellucida (surronds oocyte), pronuclei (nucleus of sperm and egg), compact morula (has zona pellucida and compact cell mass), blastocysts
initial embryonic celvages
fertilized egg = one cell
1st clevage = two cell
2nd cleavage = 4 cell, either parallel or orthogonal
3rd cleavage = parallel goes to planar which happens about 20% of time OR orthogonal goes to tetrahedron which happens about 80% of the time
fluid pressure in controlling embryo size and cell fate
early blastocyst has low pressure vs late has high pressure
factors and mechanisms inducting senescence in invitro-produced embryos
factors = stress-induced senescence: oxygen tension, temperature, pH, light, fetal calf serum , culture media composition
mechanisms = metabolic stress, epigenetic alterations, oxidative stress, DNA damage, telomere shortening
senescence = cells don’t proliferate aka sleeping cells
ectopic pregnancy
development outside the female repro tract
embryogenesis
first differentiation is development of inner cell mass and trophectoderm = placenta vs embryo happens at 4 cell stage
embryo development
zygote = fertilized egg at d1, can tell by two/bi-nuclei and 2 polar bodies to morulla (compact) to blastocytes (attaches and implants to uterus wall
Yap
transcription factor when phosphorylated it is in cytoplasm and can’t do anything vs when not phosphorylated can move around nuclease and turn on genes for placenta development (happens in outside/edge cells of morula) mouse specific
placenta elongation
happens in sheep does not happen to humans
OCT 4
marker for ICM (inner cell mass) comes later after defined TE (trophectoderm)
CDX2
placenta development, transcription factor protein bind DNA
embryo vs fetal development
embryo = organ development, can’t tell species apart from looking
fetal = organs are formed and are able to tell species different
maternal RNA degradation to embryonic genome activation
2 cell for mouse
8 cell for human
8-16 cell for ruminant
slide 11 embryo-fetal development lecture 24, could be wrong
what initiates development?
molecular changes initiate development
male and female contributions are necessary for concepts development
twinning
dizygotic = faternal, two zygotes
monozygotic = identical, from one zygote
freemartin
male and female twin where male hormones affect female twin to be sterile
caruncle vs cotylendonary
caruncle is maternal side and gets wider with development vs cotyledonary is fetal side and branches more with development
placenta morphologies
facilitate transport, endocrine organ
zonary placenta: forms ring around organism (dogs)
cotyledonary placenta
caruncles and cotyledonary, examples cow sheep
interhemal barrier
blood from the mother stays “separate” from the blood of the fetus to avoid immune response b/c foreign body. classification based on separation between fetal and maternal blood supply
epitheliochorial: pigs horses and ruminants
endotheliochorial: dogs and cats
hemochorial: primates and rodents
placenta degree of implantation
nondeciduate = fetal and maternal tissues superfically associated so no maternal tissue is lost at partition
deciduate = fetal and maternal tissues firmly interlocked so layer of maternal tissue is torn away at partition
placental shapes
diffuse, zonary, cotyledonary
what is implantation (human)
trophoblast cells proliferate and penetrate the endometrium
human placenta
semi-permeable membrane, endocrine function, no mixing of blood but exchange of material
spiral artery remodeling
in early pregnancy will have spiral artery that slowly unwinds as gestation continues
preclampsia
blood flow from mother to fetus is tightened and blocked
human and sheep placenta cells
cytotrophoblast cells: villous, proliferative stem cells
extravillous trophoblast cells: proliferate migrate, invade
syncytiotrophoblast layer: fused syncytium, nutrient/gas exhange
large offspring syndrome
calfs born way too large for mother to handle, overgrowth disorder in ruminants
usually with cloning/IVF
epigenetic phenomena in mammals
x chromosome inactivation (female eutherian mammals) genome imprinting (parent-of-orgin expression)
maternal vs paternal imprinting
maternal imprinting
limits use of maternal resources by baby in utero causing less growth
paternal imprinting
maximizes the use of maternal resources by baby in utero causing more growth
dolly
first cloning of sheep
abnormalities associated with cloning
SCNT: will have abnormal nucleus reprogramming & abnormal cytoskeleton remodeling leading to abnormal fetal placena, low preg rate, large offspring syndrome, early death in pups
VS
SCNT and injection with sperm small RNA: will have ameliorated/better abnormal nucleus reprogramming, ameliorated abnormal cytoskeleton remodeling leading to increased preg rate and birth rate, improved cloning efficiency
SCNT somatic cell nuclear transfer
growing human organs in livestock
patients cells harvested and reprogrammed -> human stem cells -> injection of human stem cells w/ animal embryo engineered to lack organ -> generation of human organ in livestock animal -> organ transplantation
usually done with pigs because of size and other similarities to humans
first successful test to a pig-to-human kidney transplant donor done but recipient only lived few hours?
AI & genetic selection
AI gives extensive progeny from superior males through intensity
fertility traits in commercial sires: health and fertility traits (daughter preg rate, cow conception rate, heifer conception rate, CFI calving 1st insemination)
calving (dtr calving ease, daughter stillbirth)
sire calving ease & daughter calving ease
main concern when we use a few super sires
inbreeding = the probability that the two genes at any locus are identical by descent, that the common genes are copies of one of the genes carried by the common ancestor a few generations
spermatogenesis definition
process by which spermatozoa are formed = cell divisions and morphologic changes
spermatogenesis point
specialized final product: haploid (1n) cell, increased genetic variation, transformation into elongated/flagellated/highly condensed cell
continuous supply of gametes, local immunological regulation to avoid new cells destruction
spermatogenesis 3 phases
- proliferation phase (spermatocytogenesis
- meiosis
- differentiation phase
spermation
release of spermatozoa into lumen of the seminiferous tube
aka spermatogenic wave
where does spermatogenesis occur?
seminiferous tubules among the testicular parenchyma
basal compartment to peripheral adluminal compartment
seminiferous epithelium
spermatogonia (elongated cells) to primary spermatocytes to spermatids round to spermatozoa
maturation of sperm in seminiferous tubules
spermatogenesis overview
spermatocytogenesis of mitosis to increase number then meiosis to increase variation then spermiogenesis to fully mature sperm/get a specialized final product
first step spermatogenesis
proliferation (spermatocytogenesis) = mitotic divisions, proliferation and maintenance of spermatogonoia
second step spermatogenesis
meiosis = go to 1N, growth in genetic variation
end product is spermatid
third step spermatogenesis
differentiation (spermiogenesis) from spherical spermatids to spermatozoa w/ golgi phase, cap phase, acrosomal phase, maturation phase
spermiation
continuous release of spermatozoa into the lumen of the seminiferous tubules, maturation in the epididymis (shedding cytoplasmic droplets)
capacitaiton: ability to penetrate the zona pellucida in the female repro tract
female gamete supply
is completely produced before birth, maturation meiosis and release of gametes is pulsatile after puberty ovulate every 3 - 4 weeks
menopause (humans) the permanent cessation of menstruation due to depletion of gametes
male gamete supply
after puberty male gametes are formed continually and uniformly throughout reproductive livespan
seasonal breeders are an exception and produce spermatozoa only during breeding season
male dynamics of gamete production
cycle of seminiferous epithelium –> progression though series of cellular stages at one location along the seminiferous tube
spermatogenic wave
sequential ordering of stages along the length of the seminiferous tubule
this phenomenon ensures that spermatozoa are produced continuously
leydig cells
in clusters between the seminiferous tubulues, produce testosterone, with LH receptors
androgen production w/ primary function of initiation and maintenance of spermatogenesis (hour intervals not days like female)
sertoli cells
support spermatozoa production with FSH receptors, nurse cells, provides nutrients during spermatogenesis, produces hormones (inhibin, anti-mullerian hormone)
from the blood-testis barrier –> separating the interstitial blood compartment of the testis from the adluminal compartment
sertoli cell & leydig cell in summary
sertoli have FSH receptor and govern spermatogenesis
leydig cells have LH receptor and produce testosterone
implications of repro performance revenue
of calves sold: more total calves % retained for replacement
weight of calves sold
implications of repro performance expense
cost of non-producers in the herd: yearling replacement heifers, open cows
cost of young cows (2 yo) in the herd: additional feed labor and other resources, additional risk/lower performance
the economic value of beef females at different ages
1-4 yo slowly increase then steady decline after about 4 to 5 yo
what is good repro performance metrics
preg rate = #preg/#exposed (consider # of days in breeding season)
calf crop % = # calves weaned/#preg cows
calving interval = average birth date relative to the start of breeding season
factors affecting repro (6)
nutrition, postpartum interval, innate fertility, disease, dystocia, bull management and exposure
nutrition (1st factor affecting repro)
BCS @ calving, trend in BCS during breeding season
adequate body condition is the key (prior to calving, trend during the breeding season), strategies for monitoring and making adjustments (structured system to monitor BCS)
match stages of production with nutrient availability in forage (calving season, weaning date) supplemental feeding to compensate for deficiencies in grazed forage
post-partum interval (2nd factor)
defined calving season, breed heifers early season (30 days)
innate fertility (3rd factor)
fertility has a low heritability, heterosis has a large impact on fertility, effect of heterosis on repro traits, matching biological types to environment
disease (4th factor)
manage risks: vaccinate for repro diseases, trich test bulls, have a biosecurity plan (open cows, purchased cows, neighboring cows)
dystocia (5th factor)
bull selection, calving season, equip females to deal with the challenge of partition, early intervention when necessary
bull management and exposure (6th factor)
nutrition, breeding soundness exam, correct bull to cow ratio = 1:30 fairly standard company wide, adjust for pasture and stocking conditions (size of pasture, terrain, # of water sites, stock density)
genomics history
DNA markers matched to genetic information learned through traditional methods
grounded in familiar things –> 1895 USDA collects milk and fat records then 1936 first national sire evaluation now millions of records
2009 genomic evaluations official, 2010 evaluations using 3k markers
now over 5 million dairy animals genotyped
providing for every animal, the continuum of car
predict & plan: which animals are likely to get a disease?
prevent: what are the protocols recommended to prevent disease
detect: which animals are likely to get a disease, can we find an illness early and mitigate?
treat: if we can’t prevent what treatments will provide the best outcome
clarifide plus (genotyping guy) can provide more opportunity for wellness and profit
just looking at phenotype will not give you same inside as genotyping the animal to know its performance
official CDCB evaluation: parentage, production, fertility, longevity milk quality and calving, functional type
z cow wellness: mastitis, lameness, metritis, retained placenta, disposed abomasum, ketosis, milk fever, cow respiratory
z calf wellness: calf viability, calf respiratory, calf scours
genetic conditions: POLLED TEST (no fee), milk components, genetic conditions, infertility haplotypes
z fertility: abortion, twinning, cystic ovary
millk genetics vs phenotype contrast of results
2214 lb milk difference between best and worst 10%
7724 lb milk difference between best and worst 10%
best 25% DWP$ group stayed in the herd 202 days longer than the worst 25%
w/ clarified scours 83% reduction in prevalence from the worst to best group
dairy wellness profit DWP$
a selection index that expresses the expected lifetime profit for an animal
production (36%) cow wellness traits (23%) longevity milk quality & calving (13%) fertility (12%) functional type (10%) calf wellness traits (6%)
genotyping/genomics clarifide summary
marginal milk is king: mature cows give 25% more milk than 1st claf heifers (our best 2 yo don’t milk quite as much as out average 5 yo) cows/heifers that avoid health events net more milk than those that don’t
clarified polus predictions translate to real performance differences: producers need to keep up as the industry progresses
newborn dairy calf management critical points
before calving: records, dry and close up cow
at calving: calving assistance
after calving: environment, immediate car, colostrum, STP
on dairy farms calving means
dam starts new lactation –> new productive cycle, heifer calf represent the highest genetic advance of the herd and a future replacement cow = dairy heifer program
dairy heifer program goals
55% mature body weight at breeding (13-15mo)
85% mature weight at calving (22-24mo)
BCS at calving 3.5
newborn challenges
immature immune system/aggamaglobulinemic, abrupt change in environment, variable amounts of body fat, small body weight, large body surface area -> quick loss of body heat, thermoneutral zone 50-78*F, prone to digestive upsets
immune system of newborn calf
antibodies can’t cross the placenta so at birth calves have a naive immune system: calves are aggamaglobulinemic, calves have the components of the immune system but it needs time to mature
passive immunity chracteristics
mediated by antibodies produced outside the body, pathogen doesn’t have direct contact with the individual, generates a rapid response, provides short term immunity, does not generate immunological memory
relies on colostrum milk from cow to calf
critical points before claving
records: expected calving date -> date to dry -> date to close up -> diet and vaccination program
hygiene in calving areas: close-up and maternity pens
critical points at calving
calving management: detection of dystocia, calving assistance, metabolic problems
critical care points after calving (environment during the first hours of life)
maternity pen
newborn pen -> protected from extreme weather, clean and dry bedding
critical care points after calving (immediate care)
separate calf from the dam as soon as possible, place calf in sternal position in a clean and dry surface, clear respiratory airway: remove membranes and fluids from the nose, stimulate breathing
rub the calf vigorously with a clean towel: stimulate breathing and dry the calf, never hang the calf upside down, feed colostrum
critical care points after calving (feeding the newborn calf)
COLOSTRUM, first milk produced after birth for macro and micro nutrients, immunoglobulins, peptides with antimicrobial activity
feeding colostrum quantity
immunoglobulin concentration: MINIMUM quality 50mg/ml
pathogen load: colostrum harvest routine, interval between harvest and feeding/store, bacterial load double every 20 min
depends on age of dam, dry period, vaccination program pre-calving, diet BCS weather, time when colostrum is collected after birth (longer time = lower quality)
feed 10-12% of body weight at first feeding –> 4 liters for a holstein calf as soon as possible after birth –> 2 extra liters after 8-12hrs
feeding colostrum quickness
two main physiological changes after birth
1. intestine of the new born claf
2. amount of antibodies in colostrum
“race between bacteria in the environment and absorption of IgG”
colostrum harvesting
hygiene! closely related with colostrum bacteriological quality
establish a colostrum harvesting routine: milk cow as soon as possible after birth clean the teats as in the milking routine, use clean gloves to perform the harvesting, disinfect equipment, change gloves once done harvesting, test quality of fresh colostrum and decide to feed or store, never leave colostrum at room temp, before to feed claves/store colostrum make sure bottles etc disinfected
storing colostrum
be prepared
store colostrum with minimum 50mg/ml immunoglobulins, reduce temp as fast as possible
refrigerate up to 3 days, freeze up to 6 months, pasteurize then refrigerate or freeze
feeding colostrum do not
feed low quality
feed bloody colostrum
feed colostrum from cows positive to mycobacterium paratuberculosis
feed colostrum contaminated with feces or dirt
pool different quality colostrum
evaluation colostrum program
serum total protein STP: on-farm analysis to evaluate passive immune transfer in healthy calves (24 hr up to 7 d), high correlation between STP and serum IgG, STP is cheaper/easier than serum IgG
STP standards for passive immunity transfer
increase serum total protein amount to be considered excellent v good v fair v poor
colostrjm management practices are successful when: less than 10% of the animals are in the poor category, at least 40% of the tested animals are excellent
records and personnel training
basic records: date and time of birth, dam ID, calf ID, calving ease, colostrum feeding, colostrum quality
advance records: proposed dairy calf birth certificate data and death loss categorization scheme, training should be provided at least once a year, all new employees should be trained and follow same protocols
dairy calf management take-home message
at birth calves are aggamaglobulinemic with an immature immune system
first hours after birth are crucial for rearing programs
prevent pathogen contamination, provide adequate environment for newborn claves, provide clean and high-quality colostrum
colostrum is the key to good health start
reduced fertility affects (5)
productivity, animal longevity, animal welfare, economics, operation sustainability
causes of reduced fertility noninfectious vs infectious
noninfectious: toxic, environmental, genetic, physical trauma
infectious: bacteria, viruses, protozoa, fungi
reproductive pathogens …(overview)
are often difficult to identify
may pose a zoonotic risk
records (breeding vaccination)
samples collection and handling
disinfection, isolation PPE
bacterial pathogens (3)
leptospira
campylobacter
brucella
leptospirosis overview
gram +, hardjo-bovis = host adapted to cattle so live in harmony with cattle, only causes little loss and won’t see as a producer, abortion rates 3-10% , zoonotic risk
leptospirosis pathogenesis
entry though mucous membranes or skin abrasions –> bacteremia –> infects kidney and repro tract
placenta –> hemolytic crisis –> fetal death (usually late gestation)
persists in proximal renal tubules –> shed in urine and in milk
leptospirosis clinical signs
non or mild acute clinical signs
abortion, still birth, weak calves: if infected for the first time when pregnant (weeks after infection, no illness in dam, sporadic/host adapted)
reduced fertility: increased services per conception, prolonged calving intervals
leptospirosis diagnosis
maternal and fetal serum: serology
fetal kidney fluids: immunofluorescence
maternal urine: culture, fluorescent antibody testing PCR, paired serum samples
dark field micrioscopy
leptospirosis control
vaccination: 5-way vaccine and monovalent vaccines, renal colonization and shedding
reduced exposure: standing water, resivors
treatment: antimicrobial therapy
leptospirosis zoonotic risk
exposure through raw milk, urine, repro tract
disease of fever, chills, muscle aches, vomiting, rash, jaundice, weil disease kidney/liver failure meningitis
leptospirosis basics
hardjo-bovis host adapted, through mucous mebranes, shed in urine or milk, decreases fertility, diagnosed through maternal and decal serum and kidney and fluids, zoonotic risk
campylobacteriosis (vibrosis) overview
venereal disease cattle to cattle sex, gram curved rod, zoonotic risk? jejuni, fetis sporadic abortions
campylobacter pathogenesis
venereal transmission (contaminated bedding bulls, contaminated instruments AI or semen
organism invades cervixand uterus
endometritis and placentits with necrosis of cotyledons
early embryonic death
carrier stage is variable length
campylobacter clinical signs
temporary infertility, death of late embryo/early fetus, sporadic abortions around 4-8 month gestation, repeat breeders, dairy cattle irregular estrous cycles, beef cattle small calf crops and prolonged calving season
bulls are asymptomatic, older bulls>carriers preputial and penile epithelial crypts
campylobacter diagnosis
herd hx, fluorescent antibody, dark field microscope, culture-fastidious
campylobacter control
AI
bull management: testing
vaccination: bulls, heifers ,cows, oil-adjuvant vs aluminum hydroxide bacterins, duration of protection vs side effects
treatment: antimicrobial therapy for bulls
brucellosis
brucella abortus
gram cocobacillus
cooperative state federal brucellosis eradication program: since 1934 because major zoonotic risk and all states free in commercial herds but prevalent in wildlife especially Yellowstone
brucellosis pathogenesis
ingestion of bacteria in aborted fetuses, fetal membranes and uterine discharge, regional lymphnodes, bacteria mammary glands, uterus, chronic palcentitis, endotoxemia, fetal death and autolysis, variable incubation period incubation period variable inversely related to gestation (exposed earlier in gestation then takes longer)
ingestion of bacteria in aborted fetus, fetal membranes and uterine discharge –> entry through mucous membranes, wounds, venereal transmission (rare) –> regional LN, bacteremia, mammary glands, uterus (2nd trimester) –> chronic placentitis endotoxemia fetal death and autolysis (after 5th month)
brucellosis diagnosis
samples for isolation: fetal abomasal fluid, lung, placenta, uterine fluid, milk
serologic tests, smears, culture, fluorescent antibody
placentitis
brucellosis control
vaccination: breeding heifers <1yo, RB51 vaccine (live), differentiates between field strain-infected and vaccinated cattle, old vaccine-strain 19 vaccine
vaccination of pregnant animals, abortion and zoonotic risk
screening programs: milk ring attest (dairies), blood test at salebarn/slaughter, herd testing (slaughter of infected) interstate transport
brucellosis zoonotic risk
raw milk consumption, handling aborted fetus/uterine fluids, vaccination, orchitis, arthritis, undulant fever
bovine herpesvirus-1 overview
infectious bovine rhinotracheitis
endemic in cattle- frequently diagnosed
abortion storms followed by respiratory and conjunctival disease
latent infections: trigeminal and sacral root ganglia, carrier for life
bovine herpesvirus-1 pathogenesis
exposed to respiratory reproductive or ocular secretions, viremia, placentitis, abortions 2nd-3rd trimester variable time after exposure autolyzed fetus placental edema
bovine herpesvirus-1 clinical signs
sporadic abortions (storms if suseptible herd) oustular vulvovaginitis, balanoposthitis, necrotizing oophoritis
bovine herpesvirus-1 dignosis
herd hx, viral isolation, immunofluorescent staining or immunohistochemistry (kidney, liver, adrenal, placenta) serology (difficult to differentiate between vaccination and natural infection, paired serum sample)
bovine herpesvirus-1 control
vaccination! MLV approved for pregnant cattle only if previously vaccinated prior to breeding, annual revaccination, abortions possible, temporary infertility-follicular necrosis in naive animals timing is critical, also killed and intranasal vaccines
bovine herpesvirus-1 virus basics
widespread in cattle populations, non cytoplasmic type 1 and type 2, clinical signs vary according to time of exposure, persistently infected animals (survival of virus, immunosuppression)
pathogenesis: contact (ingestion) -> viremia -> fetal infection
bovine herpesvirus-1 clinical signs in calves
microphthalmia, hydrocephalus, cerebellar hypoplasia, hypomyelination, alopecia, growth retardation
bovine herpesvirus-1 repro signs
insidious repro performance reduction to abortion storms, early embryonic death (ovarian dysfunction, uterine inflammation, direct damage to embryo) depending on time of infection can have reabsorption, mummification or expulsion
bovine herpesvirus-1 diagnosis
serology: infection vs vaccination
virus isolation- fetus: fluorescent antibody liver, kidney
PI animal identification (persistently infected): ELISA <4mo ear notch >4mo serum
bovine herpesvirus-1 control
closed herd, testing of herd PI animals, vaccination (decrease disease wont prevent fetal infection all the time)
cryobiology
studyof the effect of very low temps on living organisms for biological system
minimum of -100*C
supercooling and seeding
supercooling = highly unstable, lower the temp increased chance of ice nucleation
seeding critical to embryo survival
in solutions with cryoprotectants solutions may be 10C below freezing point before ice nucleation occurs
inconsistent cooling profiles from embryo to embryo
seeding should occur at -6C and not while ramping to lower temps
decreasing temps
more crystalization
isotonic solutions
no movement of water
hypertonic solutions
loss of water
hypotonic solutions
gain of water into cell
cryopreservation cooling rate
as ice crystals form, embryo is constantly equilibrating to the changing medium
cooling rate must be sufficiently slow to allow equilibrium and dehydration of the embryo
rapid cooling will trap water inside cells of the embryo which can crystalize = embryo death
cryopreservation sources of injury
low temps: alters biochemical reactions, changes physical properties of cell membranes
crystallization of water: dehydration of cells, distortion or damage of cell membranes, solution effects
how to they (embryos) survive in cryopreservation?
cryoprotectants! decrease ice formation, maintain cell volume, limit macromolecular denaturation
ex: alcohols (adonitol, ethylene glycol, glycerol) amines, inorganic sulfates, macromolecules, sugars, DMSO
top 3 cryoprotectants
ethylene glycol (1.5M), glycerol (10%), DMSO
decreasing ice formation in cryopreservation
osmotic pressure: dehydrating cells, cell permeability less to CPA than water, decreases solute concentration in cells
freezing point depression: 1 mole of solute per kg h2O decreases freezing point by -1.86 C
penetrating cryoprotectants
glycerol DMSO ethylene glycol: diffuse across membranes and exchange for cell water, maintain cell volumes, prevent fracturing of cell membranes hardened during freezing
non-penetrating CPAs
prevent excessive swelling of cell by drawing water out, typically sugars, do not move across membranes in relevant time frame
cryopreservation thawing
critically important that it be done correctly, most injuries occur during thawing, slow freeze slow thaw
for vitrification thaw as quickly as possible
vitrification vs controlled rate freezing
controlled rate “slow” freezing: prevent ice crystal formation within the cell and thin layer of media surrounding cell
vitrification: prevent ice crystal formation within the cell and in all surrounding media
embryo transfer and disease
can be used to circumvent disease such as brucellosis and johnes disease
sexing semen
separating sperm that are x and y bearing
sexed will have lower preg rates, damaged during sorting
sexing embryos
PCR to amplify the Y chromosome, decreases efficiency of embryo freezing and increase embryonic mortality
cloning (manipulating embryos)
asexual reproduction, creating genetically identical organisms, nuclear transplantation in ovum, copying an animal genetically
methods of cloning
separation of blastomeres, splitting embryos, nuclear transplantation into ovum, fusion of ovum and small cell
can be used to help endangered species
cloning practical breeding purposes
cloned females will pass on their mitochondrial genes to their offspring via oocyte cytoplasm, males whether cloned or not do not pass on mitochondrial genes to their offspring
identical twins triplets etc are natural clones manufactured clones will be less identical
cloning cell fusion
success low and variable placentas often abnormal some calves are epigenetically abnormal
serial cloning will increase percent abnormal
cloning uses outside conventional cattle breeding
“spare parts”
use somatic cell nucleus, make embryo, differentiate tissue without making fetus, will not be rejected immunologically, 10+ yr horizon
logical framework for breeding program design
goal –> breeding objective = what to change –> selection criteria = what to measure –> breeding scheme design (who to measure) –> dissemination system = what to do with good ones –> mating plan –> economic analysis = what is net worth of change
dairy evaluation and net merit
important traits to look at is productive life, daughter preg rate, CAS, heifer conception rate, cow conception rate
economically relevant traits ERT
traits that are directly associated with a revenue stream or cost of production of a commercial producer
indicator traits
traits that add accuracy to the prediction of ERT by pleiotropy
ultimately our goal should be to improve what improves our profitability
ex: measure of scrotal size with larger scrotal size meaning younger age of puberty and increase heifer preg rate
heritability
tells us how important BV is to performance
the ratio of the two variances
when heritability is low an animals own performance is not likely to be a good indicator of its breeding
factors that determine rate of genetic progress
genetic variability, generation interval, selection intensity, accuracy of selection
how does fertility relate to toher traits
profit influenced by a multitude of traits, genetic correlations and how there might be correlated response to selection
two areas of concern: carcass selection & feed intake selection
partial budget
return on investment, is what you need to spend to make the change coming back as a profit
cost of adding a nutrient vs return in specific parameters
ex: lose 60d of milk and higher feed cost vs gain in milk production over productive lifetime
achievable rate vs alarm rate
achievable rate should be goals that the farm wants to get to and alarm rate is when you should be considered how high the numbers are
he sustainability of our food systems requires balancing multiple important criteria
environment: footprints, ecosystem services/biodiversity, multi-functionality of land use, considering animal feed use from human edible standpoint
social: nutritional quality, human health, animal welfare, antibiotic technology use
economic: producer economic viability, contributions to rural economies, affordability of food to consumers
climate vs weather
weather is short term vs climate is over long periods at least 30 yrs
greenhouse gases examples
water vapor, carbon dioxide, methane, nitrous oxide
cattle contribution to global warming
feed production of 3.3 gigatonnes
livestock production 3.5 gigatonnes w/ beef being 2.9 gigatonnes
more beef produced per animal reflects systems efficiency
influences on beef produced per live animal: yield per animal, time to finish, repro efficiency, animal morbidity and mortality
sustainability bottom line
sustainability issues beyond greenhouse gas emission are critical and filled with value judgments (health nutrition climate and ethical questions are converged)
global cattle production = 9% of global GHG emission (beef 6% dairy 3%
repro efficiency is critical to optimizing productive life and diluting whole system maintenance enrgy/nutrient costs relative to beef milk production
ruminants make unique contributions to our food system via upcycling and ecosystem services
