Smith.18Peripartum Ruminant Flashcards
What is the incidence of dystocia in Holsteins?
50% of heifers
30% of cows
require calving assistance
What are examples of disorders in pregnancy and peripartum period that negatively affect the health of the dam and fetus during late gestation?
uterine torsion
vaginal prolapse
hydrops allantois
hydrops amnii
metabolic disorders
When does uterine torsion usually occur?
late first-stage or early second-stage labor
What are risk factors for uterine torsion in cows?
poor maternal muscle tone
strong fetal movement
reduced rumen fill
calf birth weigh tabove average
greater proprtion of fetuses male (63%)
higher in cows compared with heifers
what are clinical signs of a uterine torsion?
fever
tachyardia
tachypnea
straining
anorexia
vaginal discharge
Uterine torsion on rectal palpation feels like?
- dependent on whether the orsion is to the left or the right
- braod ligament is pulled tightly across the uterus
Most uterine torsions are which direction?
to the left (counterclockwise)
In a uterine torison, the uterus rolls toward which horn?
uterus rolls toward and over the nongravid horn
What is the outcome for manual delivery after correction of uterine torsion?
vaginal delivery after manual correction 20%
rolling of the cow: 18%
Cesarean section performed in 35% of cases
What is the prognosis for fetal survival in uterine torsion dependent on?
duration of parturition before intervention (longer =worse)
the presence of fetal membranes (worse with detachment)
What is the primary predisposition to cervicovaginal prolapse in cattle?
elevated plasma estrogen concentrations
What are factors that contribute to the risk of vaginal prolapse?
increased intraabdominal pressure in late pregnancy
obesity
poor vaginal conformation
Is vaginal prolapse recurrent in cows?
likely to recurr
**recommend culling when calf is weaned
what is ring womb in sheep and goats?
incomplete dilation of the cervix
Are there any predisposing factors to ring womb?
No
Is prostaglandin E2 administration effective in the dilation of the cervix?
No
What is early dilation syndrome in sheep?
Incomplete dilation fhte cervix ocurs approximately 7 to 14 days before term
**ewe has no udder or overnight blooming of udder
**lambs born alive are not viable
Early dilation syndrome in sheep occurs most frequently in:
ewe lambs
first -lambing 2 yr olds
**occasionally older ewes
Hydrallantois is often associated with disease of :
the uterus
Hyrdamnios is often associated with disease that is:
genetic or congenital defects of the fetus
**dexter cattle with bulld dog calves
angus calves with osteopetrosis
Guernsey calves iwth piutiary hypolasia or pituitary aplasia
Define hydrops allantois
progressive accumulation of allantoic fluid
accumulation of allantoic fluid from mid-gestation is associated with:
placental dysfunction
What is appreciated on rectal palpation of a cow with hydrops allantois?
tight distension o futerus
fetus & placentomes are not palpable d/t tightness of uterine wall
What is the recommended treatment for hydrops allantois?
poor px– salvage slaughter recommended
Hydraminios is associated with what?
genetic (austosomal recessive) or congenitally defective fetuswith swallowing impaired and fluid accumulates
What is appreciated on rectal papation of cow with hydramnios?
placentomes & fetus are palpable per rectum
What is the prognosis for cattle with hydramnios?
Good– calf i not viable
What is the prevalence of hydrallantois compared to hyramnios?
hydrallantois: 85-95%
Hydramnios: 5 - 15%
Define abnormal offspring syndrome:
Range of abnormalities seen with the transfer of bovine embryos producted and mainpulated in vitro resulting in abnormalities in conceptuses, foetuses, placentas and offspring
What is important in environmental management in the peripartum period in cows?
Stress (heat/col) around the tiem of parutirition may compromise fetus or neonate
When is assessment of fetal viabiity performed in production animals?
rarely done, unless prepartum dam is diseased or debilitated
Abdominal ultrasound is useful for examining ruminants peri-parturition to determin fetal viability, what parameters are seen following fetal death?
absence of fetal heartbeat
thickening of uterine wall
increased echogenciity of chorioallantoic and amniotic fluid
altered fetal posture & defnition
altered contour of the amnion
reduced fentiion and ultimately size of the caruncles
with induced parturition, when is the viability of the calf good?
within 14 days of anticipated calving date
Secretion of what prior to parturition increases and plays important role in the cascade of endocrine eentings leading to parturition?
fetal glucocorticoid hormone secretion from adrenal glands
What drugs can be used to induce partiurtion in cattle?
dexamethasone: 20 - 30 mg alone or in combination with 25 mg PGF2alpha
What drugs can be used to induce parturition in sheep and goats ?
10 to 20 mg dexamethasone and/or 15 mg PGF2alpha
What is a common complication with induction of parturition with dexamthasone and why, in cattle?
retention of fetal membranes d/t failure of immune-assessted detachment of fetal membranes & accompanying release of chemotactic factors
The efficiency of oxygen transfer to the fetus is increased in the fetus compared to adults due to:
high oxygen affinity of fetal hemoglobin
Oxygenated blood flow to the fetus is delivered through what vessel? and then pathway of blood through fetus
umbilical vein
–> anastomoses with portal vein near liver
–> 2/3rds blood shunted via ductus venosus directly to caudal vena cava
–>ca vena cava drains into right atrium
–>50% of blood shunts from R to L atrium via foramen ovale
In the fetus, pulmonary arterial resistance is higher than systemic arterial resistance, what percentage of pulmonary artery flow is shunted into aorta vs perfusing the lung?
Pulmonary artery flow:
70% shunts via ductus arterious into aorta
30% perfuses the lung
What vessels carry blood back from the fetus to the placenta via the umbilicus?
2 umbilical arteries arise from the aorta in teh region of the last lumbar vertebra
**predominantly carrying venous blood back to placenta
The majority of lung fluid in the fetus is absorbed through alveolar walls in the initial stages of ventilation, what is this mechanism controlled by?
activaiton of adrenaline-mediated alpha-adrengeric receptors in the pulmonary epithelium
Pulmonary ventilation decreases pulmonary vascular resistance, promoting perfusion of ventilated alvolar tissue. The increased O2 saturation of blood sitmulates close of what structure?
The ductus arteriosus w/in 4 to 5 minutes of birth
When does the foramen ovale close in the fetus?
Functionally closes with 5 to 20 minutes of birth
Why does the foramen ovale close soon after birth?
Increased pulmonary venous return raises blood pressure in teh left atrium, reversing the right to left shunt
What is the name of tissue that closes the foramen ovale?
The septum secundum
**thin fold of tissue that lies in cloe apposition to eh foramen & acts as a valve closing the opening
When does anatomic closure of the foramen ovale and ductus arteriosus occur?
within several weeks
Explain the mechanism, with dystocias why we see continued right to left vascular shunts?
Dystocia– prolonged hypoxia & acidosis
–>maintains constriciton of pulmonary arterioles=
maintenance of high pulmonary vacsulr resistance=
favored maintaince of R to L shunt
What is the normal duration of stage 2 labor in ruminants?
multiparous animals- 30 minutes
primiparous animals - 60 minutes
Fetal viability in ruminants is improved with early intervention in a dystocia, when should you intervene?
multiparous animals: assisted within 30 to 60 minutes
primiparous animals: assisted within 60 to 90 minutes
How do newborns maintain thermoneutrality?
Maintained via shivering and metbaolism of brown adipose tissue
In older cows what are the common causes of dystocia?
weak labor secondary to:
hypocalcemia
uterine torsion
incompelte cervical dilation
What is a common cause of dystocia in heifers?
fetoplevic incompatibility
During parturition what reflexes can be tested in the calf presenting in anterior presentation?
Reflexes:
- interdigital
- bulbar
- swallowing
During parturition what reflexes can be tested in the calf presenting in posterior presentation?
Reflexes:
- interdigital
- anal
pulses in umbilical cord
Failure to elicit reflexes/responses in the fetus during parturition is confirmatory of death?
No
**because failure to elicit relfexes can be observed in severely acidotic live calves
Post birth when should calves:
- head right reflex?
- sternal recumbency?
- attempts to stand?
- head right reflex: immediately after birth
- stneral: 2 to 4 minutes
- Stand: 15 to 30 minutes (calves) (10 to 20 minutes lambs)
Failure of maternal bonding is more common with
primiparous dams
multiple offspring
following delivery via caesarean section
If calf does not breath or move spontaneously within a few seconds of birth, what can be performed to initiate a gasping reflex?
tactile stimulations;
insertin finrge ro legnth of straw in nasal cavity
inching the nasal septum
rubbing calfs body with straw or towel
pouring cold water in ear or over the head or body of calf
In dyspneic neonatal calves the, the respiratory center can be stimulates with respiraotry stimulants, such as
doxa pram (1 to 2 mg/kg IV)
**drug is nonselective
**caution in repeat dosing d/t vosulions in hypoxic neonate
Thermoregulation is important as recovery from acidosis is dlayed by hypothermia. Cold stress lead sto:
increased metabolic needs
produces hypoxia
hypercarbia
metabolic adisosis
potentailly hypoglycemia
