Reproduction Flashcards
where is the control of the oestrus cycle begin?
hypothalamus releasing pulses of GnRH
what does GnRH work on?
pituitary gland to secrete FSH and LH
how long does it take a follicle to be released from the primordial follicle pool and become a dominant follicle?
3 months
what things can have an effect on the brain, which in turn can effect fertility?
energy
stress - lameness, nutrition…
photoperiod
what feedback loops does oestradiol have?
negative on LH and FSH
what happens to the first follicle when the cow returns to ovarian activity after calving?
there is no progesterone so the follicle will be smaller - so this oestrus may be silent
what is a silent oestrus?
no behavioural signs of oestrus
if there is progesterone available as another follicle develops, what happens to the developing follicle?
atresia
how is metestrus detected on vaginal examination?
blood in the discharge
when does progesterone increase?
after ovulation when a CL is present
how many follicular waves are usually present in a oestrous cycle?
2 (some have 3 but takes more energy)
how long does it take beef cows to return to oestrus?
up to 3 months
what does success of AI depend on?
fertility/sires
reliable oestrus detection
what is the best sign of oestrus?
cow standing to be mounted
if a cow sniffs the vulva of another cow, which cow is in heat?
cow that is sniffing
if a cow rests her chin on another cow, which one is in heat?
either or both
if a cow is licking another cow, which one is in heat?
either or both
if a cow is binding another cow, which one is in heat?
either or both
if a cow mounts another cow, but on the head end, which one is in heat?
the cow doing the mounting
if a cow mounts another cow, which one is in heat?
the one being mounted (stands to be mounted)
when is the most common behaviour seen when a cow is in heat?
sniffing and chin resting
what are some aids for heat detection?
tail paint and kamars
records - target those in oestrus 21 days ago
teaser animal
pedometers
what is the best way to detect heat?
observation and pedometers together
how many sperm are in an AI straw?
conventional - 15-20 million
sexed - 1 million
what is the role of KPIs in relation so fertility?
demonstrate efficiency, animal health/welfare and provides a benchmark
what are some recording systems for farms?
on farm diary
computer packages - milking parlour data, activity/rumination monitoring
milk recording companies
what assessments of animals can be made as a rough look at fertility?
BCS
type
cleanliness
what is submission rate?
the number of animals served that are eligible
what is first service submission rate?
the number of animals served in their first service out of their voluntary waiting period
what should the calving to first service interval be?
roughly 75 days
why is calving interval not a great KPI?
has to have had at least 2 calves for this to work (doesn’t work as a representation of the herd if lot of heifers are present)
what is conception rate?
percentage of animal that are pregnant that have been served
what are the advantages of early PD?
identify empty animals early to treat problem
what is preg rate a combination of?
conceptions rate and submission rate
what is preg rate?
number of cows pregnant that are eligible to be pregnant in a 3 week block
what should the inter service interval be?
3 weeks (time in-between each service)
how many days after fertilisation is the embryo implanted in embryo transfer cases?
day 7 (16 cell embryo)
what happens for maternal recognition of pregnancy?
the embryo implants and progesterone/oxytocin stay high meaning no prostaglandin is released by the uterus
what day does the embryo implant?
16 (days after fertilisation)
when does a pregnancy become visible using ultrasound?
around day 27
what is the trigger for calving?
calf (foetal stress response)
how does the calf trigger calving?
produces cortisol which helps the calves lungs develop and triggers the increased release or prostagladin and progesterone to trigger parturition
when in a cows life must resumption of cyclicity occur?
puberty
onset of seasonal breeding
recovery from NEB
post partum
what happens for a cow to resume cyclcity after calving?
increase in FSH stimulates first follicular wave 2 weeks post partum
what two hormones are low after calving?
progesterone and oestrogen
why may fertilisation fail or embryo losses occur?
poor AI technique/timing
poor oocyte quality/health
uterine environment
infectious agents
metabolic status of dam
genetic abnormalities
what is the biggest risk factor for uterine infection?
retained foetal membranes
what is metritis?
an abnormally enlarged uterus and purulent uterine discharge in the vagina within 21 days of parturition
what are the consequences of uterine infection?
damage to uterus
suppression of hypothalamic GnRH and pituitary LH secretion
what are the main pathogens causing uterine infection?
E. coli
Trueperella pyogenes
Dichelobacter nodosus
Fusobacterium necrophorum
what increases the risk of uterine infection?
multiparous
dystocia
abortion
retained foetal membranes
what is a grade 1 metritis?
enlarged uterus and purulent uterine discharge but no pyrexia or illness
what is a grade 2 metritis?
puerperal metritis - systemic illness with milk drop and pyrexia
what is grade 3 metritis?
toxaemic metritis - signs of toxaemia (cold and dull)
what is pyometra?
accumulation of purulent material within the uterine lumen in the presence of a corpus lute and closed cervix
what is used to treat pyometra?
prostaglandin
what is clinical endometritis defined as?
presence of purulent uterine discharge in the vagina at least 21 days post partum
what is done with cows that retain a mummified foetus?
cull (if valuable then collect eggs)
what is subclinical endometritis?
immune cells (neutrophils) present in uterus when flushed but not necessarily any bacteria present
what are the risk factors for subclinical endometritis?
negative energy balance/ketosis
metritis
what are the two types of ovarian cyst?
follicular
luteal
what is a follicular cyst?
follicle that has grown and not ovulates so continues to grow
what is a luteal cyst?
follicular cyst that lutenises
when are ovarian cysts most commonly seen?
in cattle less than 60 days in milk
when would an ovarian cyst not be treated?
if the animal is less than 30 days in milk (usually correct themselves with good nutrition and minimal stress)
what are some risk factors for ovarian cysts?
high milk production
negative energy balance and ketosis
older cattle
twinning and periparturient problems
excess BCS at drying off
what is the rule for determining if the corpus luteum or follicular cyst is the dominant structure?
if the corpus lute is greater than 2cm then the follicular cyst is hormonally inactive and all treatment is directed at the corpus luteum
what are the features of a follicular cyst?
thin wall (less than 3mm)
fluid filled (clear - no infection)
internal diameter >25mm
>10 day duration of follicle
what are the features of a luteal cyst?
luteinised follicular cyst
>25mm external diameter
thick wall >3mm
fluid filled lacuna
what does the thick wall of a luteal cyst indicate?
progesterone production
does a follicular or luteal cyst hair trabelulae?
luteal
what are the options for treating follicular cysts?
burst
GnRH
progesterone (PRID)
aspirate
how does GnRH treat a follicular cyst?
causes it to ovulate or lutenise
can you inseminate animals that come into heat after a follicular cyst?
no egg will be too old to be fertile
how is a luteal cyst treated?
prostaglandin
if unsure on whether a follicular or luteal cyst is present, what treatment is used?
progesterone device
what is the notifiable cause of abortion, which is the reason behind needing to report abortions?
brucellosis
what are the regulations behind brucellosis management?
all abortions must be reported in the UK
monthly routine bulk milk sampling
why should we try to diagnose the causes of abortion?
economic importance
vaccination
zoonosis
venereal infections
what are the two types of infectious causes of abortion?
primary agents - cross feet-maternal barrier
opportunistic - cross damaged barrier
what are some tissue the can be targeted and cause abortion?
chorio-allantois
amnion
bone
soft tissue (lungs…)
endocrine gland (adrenal…)
foetal immune cells
what is the definition of a primary abortive agent?
destroys integrity of feto-maternal unit (this may/may not cause abortion) allowing opportunistic pathogens to invade the placenta and foetus
what are some primary infectious abortive agents?
Brucella abortus
BVD
Leptospirosis hardjo
Neospora
BHV-1
parainfluenza 3
Bacillus licheniformis
fungi
what tissue do opportunistic (secondary) abortive pathogens target?
chorion and amnion
what are the main secondary abortive pathogens?
Listeria
Leptospira
Salmonella dublin
what are the three routes of infection of abortive agents?
resident flora of reproductive tract
transplanental
haematogenous
what determines the response to an abortive agent?
when the infection occurs - if the foetal immune system is functional or not
at what stage will infection with an abortive agent cause the animal to be born with a carrier status?
90-120 days of gestation
what type of virus is infectious bovine rhinotracheitis?
herpesvirus (BHV1)
will the reproductive and respiratory symptoms of IBR be present in the same herd?
highly unlikely
when can vaccination be used for IBR?
protection in the face of an outbreak (outbreak of abortions)
what is the most commonly diagnosed cause of abortion in cattle?
Neospora
what are the ways Neospora can infect a cow?
ingestion of oocyst (exogenous)
transplacental (endogenous)
how can neospora be diagnosed?
test calf at birth (show dam is infected)
histopathology of brain (dead foetus)
screen at drying off
what are some ways of controlling Neospora?
keep dogs away from cattle feed and cleansing
cull seropositives
breed to beef
sexed semen
what happens if BVD is caught in the first trimester (0-95 days)?
foetal resporption or abortion
what happens in BVD is caught from day 95-120 of gestation?
immunotolerance (PI status of calf)
what happens if BVD is caught from day 120 onwards of gestation?
seropositive calf with congenital lesions or aborted
in terms of antibody and antigens, how would a PI BVD calf be described?
antibody negative and antigen positive
what develops in PI animals with the cytopathic biotype of BVD?
can develop mucosal disease
what are the clinical signs of mucosal disease?
ulceration of mucosa (tongue, soft palate, gingiva…)
ill thrift
diarrhoea
what are the ways of diagnosing BVD?
quarterly bulk milk tank antibodies
PI in blood from one months (after MDA are gone)
ear notch test
antibody - check test of other animals in a group to see if PI is present
how can BVD be controlled?
test and cull
biosecurity
avoid co grazing with sheep
vaccinate (protects pregnancy)
where does Leptospira reside in the cow?
kidney (excreted for months/years in urine)
why is control of leptospirosis so important?
zoonotic
what are some clinical signs of leptospirosis?
(often unapparent and latent)
infertility, abortions, stillbirths, weak calves, retained foetal membranes, milk drop
what is used to treat leptospirosis?
antibiotics - oxytetracycline, streptomycin
vaccinate before turnout
what is the most common serovar of salmonella associated with bovine abortion?
S. dublin
when is the ideal time to vaccinate for salmonella?
in the run up to calving (highest shedding around calving - stress!!!)
what is the main abortive agent spread venereally?
Campylobacter fetus fetus
how can Campylobacter fetus fetus be diagnosed?
preputial washing bulls and vaginal mucus aspiration of cows
what is an uncommon cause of abortion spread by natural service? (eradicated in UK??)
Trichomonas fetus
what can be recorded on post-mortem examination of aborted calves to help the pathologist?
crow rump length (age of death)
thyroid gland weight
fractures/haemorrhages
fluid compartment (-itis)
placentitis
liver rupture
meningeal haemorrhage and oedema
what sample would be taken on post mortem of a post mortem suspected to be BVD?
spleen
what sample would be taken on post mortem of a post mortem suspected to be IBR?
liver
what sample would be taken on post mortem of a post mortem suspected to be of bacterial cause?
stomach content
what sample would be taken on post mortem of a post mortem suspected to be leptospirosis?
kidney
what sample would be taken on post mortem of a post mortem suspected to be neospora?
brain
what sample would be taken on post mortem of a post mortem suspected to be fungal?
eye lid hair follicles (hyphae in hairs)
what should always be taken from the dam and foetus when abortion has occurred?
bloods
in lambs how big should the thyroid be in grams?
foetal weight divided by 2 to 3
what does a large thyroid in lambs suggest?
iodine deficiency
what antibodies can be tested for in bulk milk samples? (relating to abortion)
BVD, leptospirosis, IBR, neospora
(take care if vaccinating)
what are the three fates of the first dominant follicle of a peri-parturient cow?
follicle ovulates
follicle turnover - new follicle rises
becomes cystic
what is the relationship between milk yield and first service pregnancy rate?
inversely proportional (as yield increases pregnancy rate decreases)
what consequences can milk fever have in terms of predisposing to other disease?
difficult calving
retained foetal membrane
endometritis
subclinical low calcium - poor fertility
how does lameness effect the monitoring of heat in cattle?
less active - pedometers not so useful (less mounting…)
high proportion of vulva sniffing and chin resting
what effect does mastitis have on ovulation?
cows take longer to ovulate when induced when they have a higher cell count (due to follicles taking longer to mature)
if the cow is known to be lame or have mastitis how could we alter service?
possibility to serve them slightly later after induction
what increases your chances of being a repeat breeder?
having uterine disease previously (or dystocia)
what is a repeat breeder?
cow that gets served but doesn’t hold
how does yield effect the standing oestrus signs?
decreases with high yielding cattle
what is the first stage if labour?
dilation of cervix
how long can the first stage of labour (cervix dilation) take?
3-6 hours
what are some possible signs of the first stage of labour (cervix dilation)?
separated from herd
appetite decreases
restless (standing and lying alternates)
thick mucus string
abdominal straining (towards end)
what is the second stage of labour?
delivery of the calf
what is the sign that stage two of labour has began?
water bag (membranes) at vulva
what is the third stage of labour?
expulsion of placenta
when is a placenta classed as a retained foetal membrane?
if it isn’t expelled within 12 hours of calving
what happens if you intervene in calving too early?
can prevent the cervix from fully dilating
what is the earliest stage to intervene with calving?
if water bag has started showing and no progress has been made after an hour
if there is extreme discomfort
if there is significant bleeding
what would be a potential problem if the calving cow has progressed to the second stage of labour after 6 hours?
twisted uterus
if a calving cow doesn’t strain when you put your hand in, what does this suggest?
cow is hypocalcaemic (give calcium)
what are some causes of dystocia?
malpresentation
foeto-maternal oversize
congenital abnormality
hydrops allantois
schmallenberg virus
primary inertia (hypocalcaemia)
what is hydrops allantois?
a lot of fluid accumulation in the membranes
when doing a vaginal examination of a calving cow, what must be examined?
lesions or haemorrhage
position of uterus and calf
relaxation/distention of vulva, vagina, cervix
signs of life
position of umbilical cord
likelihood of extraction of calf
what are the 3R’s for approaching dystocia?
reposition
repulsion
rotation
what is a good way to position the cow when calving?
downhill - uterus pushes towards diaphragm and gives you more room
what is the best lubricant?
J-lube
what can be used to relax the uterus?
clenbuterol
what is the risk with placing calving ropes/chains above the fetlock?
higher risk of leg fracture
what is the risk of placing calving ropes/chains below the fetlock?
higher risk of slipping off
what is the ideal way to place calving ropes/chains?
loop above and below the fetlock
how can you tell if a posterior positioned calf is going to be able to be calved per vaginum?
if the two limbs are able to be exteriorised past the hocks
before pulling out a calf in posterior position, what must be checked?
the position of the umbilical cord
what is episiotomy?
purposeful cutting of the vulva to allow more space for calving (uncommon in cows, can be seen done in heifers)
what should be done before opting for an episiotomy?
manually stretch vulva lips with arms for about 20 minutes
where is a cut made for an episiotomy?
10-11 o’clock or 1-2 o’clock
what is required for an episiotomy?
caudal epidural
antibiotic cover
what are some complications of episiotomy?
wound infection/breakdown
distorted vulva conformation - poor conception rates - pneumo-vaginum and uro-vaginum
weak point can effect ability to calve naturally in future
when are full embryotomy/foetotomy indicated?
large dead calf
abnormal calf (foetal monster…)
when is partial embryotomy/foetotomy indicated?
hip lock
head back - unable to correct and dead
leg back - unable to correct and back
what are the methods of passing wire for a embryotomy/foetotomy?
passing
cleat
what is the passing method for placing the wire for a embryotomy/foetotomy?
pass wire by hand around area of calf that is being removed
thread wire through each side of embryotome, tighten and check before sawing
how is the head removed in a full embryotomy/foetotomy?
passing method cutting as caudally as possible
once on leg and the head is taken off in a full embryotomy/foetotomy, what is done next?
keep one leg on, to allow to pull and give traction then remove as much of the trunk as possible then split the pelvis
what are some complications fo embryotomy/foetotomy?
uterine, cervical, vaginal tears
retained foetal membranes
metritis
adhesion formation
when do most uterine torsions occur?
at the onset of parturition (rather than during pregnancy)
what are the risk factors for uterine torsion?
poor rumen fill
space in abdomen
hilly land
lots of standing/lying
what direction do most uterine torsions occur?
anti-clockwise
how do cows with uterine torsion present?
start calving but don’t progress
no straining (Fergusons reflex not triggered)
slightly raised tail
down/toxic
what is found on examination of cattle with uterine torsion?
arm will corkscrew on vaginal exam
lip in front of cervix
palpate torsion (per rectum)
what is the first way to attempt to correct uterine torsion?
swing the calf or twist a leg of the calf
what are the ways of dealing with uterine torsion?
swing the calf
twist the calfs leg
roll the cow
caesarian
what are some complications of uterine torsion?
high degree can lead to occluded blood supply and friable tissue
dead emphysematous calf and toxic cow
what are the major indications of forced caesarians?
foetal oversizing or maternal disproportions
irreducible uterine torsion
insufficient cervical dilation
what are some minor indications of forced caesarian?
foetal malpresentation
abnormal calf
dead/emphysematous calf (embryotomy not feasible)
constricted vagina and vestibulum
what are some reasons for an elective caesarian?
double muscled breeds and embryo transfer calves (not always in the UK)
what anaesthesia techniques can be used for a caesarian?
caudal epidural
paravertebral nerve block
line block or inverted L
what is the most common anaesthetic used for caesarians?
clenbuterol
where is an incision made for a caesarian?
left flank just below transverse process and behind last rib
where is an incision made in the uterus during a caesarian in a cow with a normally presented calf?
greater curvature from hock to tip of toe
what are some complications of caesarians?
haemorrhage
peritonitis
localised adhesions
retained foetal membranes
metritis
wound infection/breakdown
what is uterine prolapse commonly associated with?
hypocalcaemia
what are quantitative genetics?
inheritance of traits that can be measured such as milk yield or muscle growth rates that can be influenced by several genes at different loci
what effects quantitative traits of cattle?
genes and environment
what is heritability?
part of the phenotypic variation that is due to the heritable gene effects
what is a breeding value?
additive genetic merit of an animal
how are breeding values predicted?
information from animals own performance and its relatives
what does a breeding value of 0 mean?
they are average of the current population (mean)
what effect does the bovine leucocyte adhesion deficiency have?
fewer neutrophils get into tissue to fight infection
what are the clinical signs of bovine leucocyte adhesion deficiency?
oral ulcers, gingivitis, pneumonia, chronic diarrhoea
death due to infectious complications
what is PLI in relation to genetics?
profitable lifetime index
