Infertility and obstetrics cattle/ruminants Flashcards
What does superfecundation mean
Offspring born from more than one sire
What does superfetation mean
fetuses developing and born at different stages; doesn’t really happen
What is the biggest cause of no offspring from a mating
Early embryonic death
Fetal mummification
Often no bacterial contamination
Resorption of fetal fluids
Fetal maceration
Fetal death with bacterial contamination so get decay in utero
Emphysematous fetus
When there is death at a late stage of gestation; e.g neglected dystocia
-> Decomposition produces gas which causes emphysema of fetal tissues
Which type of hydrops is more common
Allantois
Treating hydrops uteri in cattle
Depends on value of calf vs cow
- May do elective c section
- May just leave her; but be prepared to assist in parturition due to likely uterine inertia
- Can induce birth; but risk of calf death due to prematurity
- Can drain fluid; but will re-fill + risk of infection
What do we worry about when inducing birth of a calf
Won’t have functioning adrenal glands
How do we induce birth at different stages of cattle gestation
Up to day 100/150: CL is providing progesterone so can use PGF2alpha
From day 150-270: placenta is providing progesterone so need corticosteroids
Risk factors for vaginal and cervical prolapses
Older, multiparous animals: more relaxation of pelvic ligaments
Ruminal distension
Increased intra-abdominal pressure e.g due to straw within rumen
Oestrogens in diet (white clover)
Breed e/g Herefords
Risk of dystocia in bovine parturition
3-10%
Parturition stages in cattle and timings of it
1) Preparatory stage: 2-6 hours
- Calf rotates to an upright position; uterine contractions begin and amnion is expelled
2) Foetal expulsion: 30 mins to 4 hours
-3) Expulsion of fetal membranes: 2-8 hours
Most common causes of dystocia in cattle
Main one = feto-maternal disproportion
Then fetal maldisposition
What does presentation mean in relation to birth position
Relationship between longitudinal axis of fetus and birth canal e.g anterior or posterior
What does position mean in relation to birth position
Which birth canal surface is fetal spine applied to e.g dorsal or ventral
What does posture mean in relation to birth position
Disposition of limbs of the fetus e.g extended or flexed
Which drugs might be given during a dystocia case
Xylazine for sedation
Clenbuterol to reduce myometrial contraction strength (NB: will counteract the increased contractions caused by xylazine)
Denaverine: antispasmodic; promotes dilation of birth canal
When would we NOT use denaverine (anti-spasmodic) in dystocia
With mechanical obstruction of birth canal e.g oversized fetus, uterine torsion, fetal maldisposition
How to distinguish fore and hindlimbs when palpating fetus
Forelimb fetlock and carpus bend in the same direction
Hindlimb joints bend in opposite directions to each other
What additional signs of fetal life can we look at in a posterior presenting calf
Anal reflex, umbilical artery pulse
what do we describe as the maxmum pull that should be applied to a fetus during traction
Well coordinated pull of 4 average people
What is the most common MATERNAL cause of dystocia
Uterine inertia
Due to hypocalcaemia/magnesaemia; overstretching of myometrium e.g in hydrops, fatty infiltration of uterus, hormones
OR may be SECONDARY e.g to exhaustion
In what breed is normal delivery not usually possible due to inadequate size of birth canal
Belgian blue
Why might we see incomplete dilation of cervix in cattle (NB rare)
Most likely hormonal issues; or hypocalcaemia
May relate to fibrosis of the cervix
What is associated with incomplete relaxation of vagina and vulva
Dairy heifers
Over fat body condition
Or interruption during parturition
What direction does uterine torsion more commonly go in
Anticlockwise
Usually 90-180 degrees
When can’t we correct uterine torsion per vaginum
If anterior to vagina
Or >270 degree torsion
What is an episiotomy
Making a cut to increase diameter of vulval opening
Should be done dorso-laterally at 11 or 1 o’clock
Options to deal with feto-maternal disproportion
> Supplementing contractions with traction
Episiotomy to increase vulval opening diameter
C section
Fetotomy to reduce volume
How soon do we want a calf out within traction being applied
10 mins
At what point in posterior delivery must we avoid any delays because calf compromised
Once umbilical cord trapped; i.e after tail head and anus is out
What is ‘true breech’ presentation
Hip flexion; to correct should retropulse then push limb into hock flexion and then straighten this
What is the normal position for birth
Dorso-sacral i.e fetal spine upwards towards maternal pelvis
What does dorso-pubic position mean
Fetal spine is down towards pelvis i.e upside down fetus
What does dorso-iliac position mean
Fetus lying on side
How can we use pressing eyeballs in calves to correct faulty position
Triggers a convulsive reflex
How many cuts does a complete fetotomy usually require
4-6
Difference between a subcut and percutaenous fetotomy
Subcut is within skin; can be used to remove forelimb in anterior presentation; incise skin a little and break down muscle
Percutaneous = making full cuts through body
What is the most common reason for fetotomy
HIp lock
post-fetotomy management of a cow
Uterine flushing
Oxytocin to aid involution
NSAIDs and antibiotics
Fluids
What is prognosis of a c section most related to
Duration dystocia has been left
What is the preferred surgical site for cow c section
Left flank standing laparotomy
What is a complication with giving xylazine for sedation during c section
Increases the intensity of uterine contractions
+ can reach calf and cause sedation; reduces fetal cardiovascular function
What is a side effect of clenbuterol (for myometrial relaxation)
Delays uterine involution
Options for cow c section anaesthesia
Line block; over incision site BUT delays healing
Inverted L block; above and to side of of incision - won;t affect healing
Paravertebral block
Can do epidural
What limb will we palpate during c section depending on presentation
If anterior; will feel hindlimb
If posterior; will feel forelimb
How to repair a uterine incision; abdomen and skin
Continuous layer of inversion sutures for uterus
Continuous sutures for muscle
Non-absorbaby ford-interlocking or horizontal mattress for skin
When might we choose a right flank incision for C section
Lots of previous C sections so much scar tissue
L side not accessible
Fetus in right horn
When might we choose a ventral/midline incision for C section
If calf dead/emphysematous to avoid fluid spilling into the cow
- Must sedate cow and cast in lateral recumbency
MOst common causes of dystocia in EWEs
Most common = fetal maldisposition
Then obstruction of birth canal
MUCH MORE RARE to have it due to disproportion
Considerations when approaching dystocia in the ewe vs cow
Uterus more friable so take care
+ More risk of infection so must be more hygienic
Tissue breaks down easier so easier to do a subcut fetotomy compared with cow
What position do we normally do a c section in a sheep
Lateral recumbency
Treating acidosis in neonatal calves
Inject 50ml of sodium bicarbonate
Incidence/consequences of retained fetal membranes in cows vs sheep
More common in cows
BUT worse consequences in sheep
How common is RFM incidence in cows
8-12%
Risk factors for RFM
NB: management factors involved because separation process starts weeks pre-partum
- Age, dystocia, multiple births, inductino
- infection-related abortion
- Deficiencies in cit A, E, selenium, Ca2+, Cu2+, iodine
- High body condition; fatty liver syndrome
- Hormones; lack of PGF2a, low progesterone, hgih oestradiol
What treatments can help with RFM
Avoid manual removal esp on septicaemic animals
Antibiotics; only if systemically ill + only parenteral
Hormones: PGF2a if low in this; oxytocin if in first 24hours post-partum
Contributing factors to uterine prolapse
Poor uterine tone
Oversized fetus
Prolonged dystosia
Increased intra-abdominal pressure
High oestrogens in diet
Too high BCS
What is the New Zealand method for correcting uterine prolapse
Pull back legs all the way back; then sit between legs and correct
In what breeds do we sometimes see congenital ovarian hypoplasia
Swedish Highlands
White ayrshire
At what age should cows be cycling
By 12 months old; but may be later if underfed
What is white heifer disease
form of segmental aplasia due to sex linked recessive disease
- Get occlusion of the genital tract due to incomplete canalisation or septae presence
What are freemartins
Females which have been exposed to testosterone in utero due to male twin (NB: male may have died in utero)
- Get absence of normal repro tract, masculinisation of calves e.g prominent clitoris; short vagina; testes present
> Diagnose definitively via blood test
90% of females with male twin affected
What are ovario-bursal adhesions
Fibrous tissue that sticks ovaries to ovarian bursa; impacts ovulation
Usually on R side
What is hydrosalpinx
Where there is blockage of ovarian tubes which then fill with secretion; tubes will become palpable
What is the most common type of ovarian tumour
Granulosa cell tumour; usually oes producing so get nymphomaniac behaviour
effect of fibropapillomas in uterus and cervix on fertility etc
No effect on fertility
BUT can interfere with parturition
Which type of cows are often 3 wave rather than 2 wave
Beef cows
Dairy heifers
How does maternal recognition of pregnancy in the cow work
Fetal trophoblasts secrete IFN-tau from day 14; this blocks oxytocin receptors on the uterus so they don’t respond to oxytocin
–> Don’t release of prostaglandins
What is anovulatory anoestrus
No ovulation
see small flattened ovaries, no CLs, no uterine tone, little vaginal mucus
Follicles are <8mm
What is the minimum size follicle for ovulation in a cow
8mm
What can we tell about where the problem is in follicular development based on follicle size
If all <4mm: likely from emergence to selection i.e FSH issue (severe malnutrition)
If 4-8mm: issue from selection to dominance; GnRH issue
If some >8mm: issue is with ovulation i.e LH surge
In anovulatory anoestrus; what size follicles can we use GnRH on to cause ovulation/leutinsation or atresia
> 4mm
If less than this = a DEEPER ANOESTRUS so this is less likely to work
What do we use to treat deep anoestrus in cattle
Progesterone vaginal implant; should get resumption or normal cyclical activity once removed
Why do we use eCG in treating anoestrus in cattle
Has FSH-like activity
Difference between follicular and luteal cysts
Follicular cysts are thin walled
Luteal cysts are thicker walled (>2mm) with luteal tissue
Why might early CLs be misdiagnosed as luteal cysts
They have a fluid centre at the start (trapped during formation) BUT this will be gone by the time of normal PD diagnosis
Why do we get cystic ovarian disease
Lack of LH surge so follicles continue to grow without ovulating
Approach to treating follicular vs luteal cysts
Follicular: can give GnRH to cause LH surge; hCG/LH; progesterone to re-establish hypothalamic action
Luteal cysts: progesterone; PGF2alpha for luteolysis
What are possible causes of lack of oestrus but CL present
MOST LIKELY = JUST MISSING OESTRUS SIGNS
- Persistent CLs
- Subclinical endometriosis; can cause failure of uterus to release PGF2alpha
To treat can use PGF2alpha to get rid of CL
How could we deal with delayed ovulation causing inappropriate insemination timing
Give GnRH at service to induce ovulation
What is the main cause of repeat breeders
Ovum not reaching sperm e.g due to ovarian bursal adhesions
How could we deal with poor quality CLs in high yielding dairy cows
Give GnRH at service and/or 11 days later to cause development and leutinisation of other follicles
What can cause short cycles
Cystic ovarian disease
At what % mature weight/age should we serve heifers
60% mature weight
Usually about 15 months old
How can negative energy balance affect fertility
Reduced LH pulse freq
Reduce insulin
Reduced oestradiol from follicles
Deleterious effects of BHBs and NEFAs
Why should we avoid excess rumen degradable protein in relation to fertility
Ammonia and urea have negative effects on oocytes and embryos
+ can exacerbate -ve energy balance because uses energy to make this safe
timing of ovulation in relation to oestrus
Ovulation 12-18 hours after the end of oestrus
- Follow AM/PM rule
Which opportunistic bacteria causes non-specific infections of genital tract
Staph, strep, trueperella, E coli, other anaeroes (fusobacterium, clostridia, bacteroides)
Under which hormone dominance is the immune system weaker
Progesterone
(to avoid new conceptus being seen as foreign)
What is metritis
ACute-peracute inflammation of endometrium/myometrium after calving
> may be subclinical or be more peracute with toxaemia
Why might we avoid doing uterine irrigation in acute metritis cases
Uterus is friable so risk of rupture
how do we grade endometritis
Baseon on what the secretion looks like
From 0-2; 0 = normal, 2= 50% pus/mucus
How do we treat endometritis
With inter-uterine antibiotic e.g cephalosporin via catheter (no milk withdrawal)
+ may do hormonal treatments:
- PGF2alpha: for luteolysis of persistent CL
- GnRH for early resumption of cyclicity
Oestrogens: to increase natural defences of endometrium BUT not allowed in food producing animals
Why do we get pyometra and how do we treat
Because cervix remains closed; usually due to CL or luteal cyst
- So can use prostaglandin to lyse the CL
Which bacteria cause specific infections of genital tract; i.e without predisposing causes
Brucellosis, leptospirosis, salmonella, bacillus, listeria
Characteristics of brucellosis abortion
From 5 months +
= notifiable (causes undulant fever in man)
Infection is via ingestion of organism from recent abortion
What is the most common (ly diagnosed) cause of abortion in cattle
Neospora caninum
Characteristics of neospora abortion
4-6 months
Autolysed fetus
What is the most important route of transmission of neospora caninum in cattle
Vertical transmission
Diagnosing neospora as cause of abortion in cattle
+ve serology result NOT diagnostic
BUT -ve result does rule it out
Consequences of leptospira infection or shedding in pregnancy
Early embryonic death (infertility)
Abortion; late gestation
premate/weak calves
See sudden milk drop in mother
- NB: usually no symptoms if not pregnant
Which organ might leptospira isolate into and start shedding from
Kidneys
Which species of campylobacter causes abortion in cattle
C fetus subspecies fetus; more so abortion
C fetus subspecies venerealis; more so infertility
How does campylobacter impact fertility
= venereally transmitted disease where bull is carrier
Embryonic death and infertility; but can also get later abortion
Endemic campylobacter situation
Just subfertility because cow gets immunity
- Newly introduced animals become the ones to succumb
How can we diagnose a campylobacter abortion
Getting typical organisms from the stomach of fetus
Which strain of salmonella is most responsible for abortions
S Dublin
- May have accompanying dysentery OR no clinical signs
Which bacillus species causes abortion and at what stage
B licheniformis
Usually late stage 5-7 months
Source = poor silage
Characteristics of a listeria abortion
From poorly fermented silage
Fetus AUTOLYSED
What does serology for BVD tell us about
EXPOSURE only; but good for herd monitoring
BVD-1 impacts on reproduction
Abortion rare
Can cause infertility via embryonic death
infectious pustular vulvovaginitis; must stop natural service
how is Schmallenberg virus spread
Via culicoides midges
+ transplacentally from viraemic dam to fetus
Characteristics and causative agents of mycotic abortions
LATE TERM (7-8 months)
e.g Aspergillus, absidia, rhizpus, mucor
Diagnosis via fungal hyphae in fetal stomach or placent
Definition of an abortion in cattle
Expulsion of fetus from 150-270 days gestation
Why must we report all bovine abortions to DEFRA
Brucellosis eradication legislation
What samples should we send for investigationof abortion
IDeally whole fetus + fetal membranes
Is it easier to get heifers or cows pregnant
Heifers; because not also lactating + don’t have age-related issues
How long after parturition do farmers get dairy cow pregnant (not aiming for 365 day interval)
~ 6 months
At what point should cows have full uterine involtuion after birth
21 days
By which day post-partum should cows have had first oestrus
45 days; this is ‘voluntary wait period’ for farmers
What is calving index and how good is it as a measure of herd fertility
Interval between services; target is 365 days BUT takes a long time and is biased towards successful cows (i.e those not culled)
What does 24 days submission rate mean
% cows served within 24 day period of the START of the breeding period (after voluntary 45 day wait period)
What should the inter-service interval be
18-24 days; this is the normal length of an oestrus cycle
- IF longer means there was a pregnancy and early embryonic death
- If shorter cow is ‘short-cycling’; may be cystic
What progesterone levels do we expect in a cow in oestrus
Very low
What body condition do we want cows at service, calving and mid-lactation
Service = 2-2.5
Calving = 3-3.5
Mid-lactatino = 2.5-3
Metabolic profiles of cows; what can we use to monitor different things
BHB = for -ve energy balance
NEFA = for fat mobilisation
Urea = for daily protein intake
Albumin = for long term protein status
Globulins = for inflammation
What does low protein in milk yield or low overall yield suggest about diet
Energy deficit
What does low milk fat suggest about diet
Deficient in fibre
(no detail) options for synchronising cows
Prostaglandins
Progesterone; implant then remova;
How can prostaglandins be used to synchronise cows
Causes luteolysis and return to oestrus in 2-5 fays
> Brings lots of cows into heat at same time so will mount each other etc for detection
BUT won’t all ovulate at same time so not good for fixed time AI
How can we use progesterone to synchronise cows
Leave impant in for 12 days; then when removing it mimics CL regression SO get oestrus in 2 days
(if leaving P in for less time then will need to use a luteolytic upon removal)
How can GnRH be useful in issues with ovulation etc
As a luteotrophin or to induce ovulation
> If delayed ovulation an issue, inject at service for ovulation at predicted time
> If luteal insufficiency an issue, inject at 11 days post service to stimulate the development of accessory CLs
How can gonadotrophins be used in cycle manipulation and which ones
hCG has more LH-like activity; to treat follicular cysts or induce ovulation
eCG has more FSH-like activity; to induce ovulation (e.g in instances where progesterone has been used to advance the breeding season)
5 main categories of causes of infertility in the male
1) Deficient libido
2) INability to mount
3) INability to achieve intromission
4) Inability to fertility
5) Venereal disease transmission
What venereal disease are we worred about bulls passing to cows
Campylobacter fetus subspecies venerealis
What age is puberty usually in bulls
9-10 months
How might we treat bulls with deficient libido
Hormone therapy e.g hCG every 3 weeks for LH like activity (LH supports Leydig cells to make testosterone)
How are LH and FSH involved in male fertility
LH: supports leydig cells to make testosterone
FSH: supports sertoli cells to do spermatogensis
What penile neoplasia is common
Warts caused by papilloma viruses
What is phimosis
Inability to extrude penis through prepuce
What is paraphimosis
Inability to withdraw penis back into prepuce
What is a persistent frenulum in bulls
An adhesion from tip of penis to shaft; should have broken down at puberty
- (can be result of early castration)
Simple to correct
What ligament insuffiency causes spiral deviation of the penis
Dorsal apical ligament (holds penis straight)
- Can fix this ligament to the tunica albuginea to fix
Primary, secondary and tertiary sperm defects
Primary = at time of production
secondary = following exposure to infection or noxious agents in transit
Tertiary = during processing for AI e.g bent tails = cold shock
Difference between conpensable and non-compensable sperm detects
Compensable: can still get fertilisation by using different AI technique to reach eggs e.g bent tails
Non-compensable; e.g acrosome defects; won’t get fertilisation
What infections cause orchiditis
B abortus, T pyogenes, M bovis + some non-specific opportunists
What causes testicular degeneration
Toxic damage
Viral infection e.g BHV-1
Physical damage
Autoimmunity
Deviation in normal temp
Gonadotrophin insufficiency
-> See previous good fertility then decrease
What scrotal circumference should a bull have
> 34cm
Caution with interpreting electro-ejaculation sample
Not true ejaculate
More watery; but good for looking at sperm morphology
What sperm density do we expect in ruminants
1,000 million/ml
What are the cut offs for sperm morphology
> 70% should be normal
with <20% of any single abnormality
+ 75% should be live
