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The pregnant cow
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Veterinary Medicine
Graduate
10/29/2015

Additional Veterinary Medicine Flashcards

 


 

Cards

Term
Cow gestation
Definition
282 days
Term
Which cows tend to have longer gestation?
Definition
charolais and continental breeds
Term
Twinning
Definition

can occur in 1-4% of cow births

- increases with materna age, uncommon in heifers

- identical twins very rare in natural breeding-most are result of double ovulation

- 80% twin pregnancies bicornual, 20% unicornual

- calve out earlier, more post partum problems, pregnancy on same side of CL

Term
placentation
Definition

cotyledonary syndesmochrial

- placental cotyledons attach to maternal caruncles to form placentomes- arranged in 4 longitudinal rows in each horn

- formed by villi containing capillaries growing from the allantochorion into the crypts of the maternal uterine caruncles

- can palpate beyond 3 months of gestation 

Term
foetal fluids
Definition

intially there is some fusion of the allantoamnion and allantochorion causing allantoic fluid to be pushed to the extremeties of the allantochorion and amniotic fluid to lie centrally. As the volume of allantoic fluid increases the allantoamnion and allantochorion separate 

2-4 months: rapid increase in volume of allantoic fluid

3-4 months: rapid increase in volume of amniotic fluid

at term: amniotic fluid volume= 5-8 L

allantoic fluid volume = 14-16 L

Term
Endocrinology of pregnancy
Definition

CL is major source of progesterone until d.150. Loss of CL up until this time, will terminate the pregnancy ( can abort with prostaglandin injection up to 120-150days - the earlier you use prostaglandins, the more effective they will be. THe CL takes about 5 days to develop, wait a week to give prostaglanding for misalliance.

Beyond 150 days, the CL isnt the sole source of progesterone, which is produced by the ovarian stroma, the placenta and adrenals. Loss of CL after 150 d. wont necessarily terminate the pregnancy

Term

Induction of parturition/ Abortion: 

cow/heifer close to or over normal gestation

Definition

Inject short acting corticosteroid or PGF2α

parutrition normally occurs within 48-72 hours 

Term

Induction of parturition:

Cow/heifer between 150-270 days of gestation

Definition

PGF2α alone will not reliably cause abortion at this stage of pregnancy. Best option is combo of dex and PGF2alpha

- abortion should occur within 5 days 

Term

Induction of parturition:

Cows/heifer <150 days of gestation

Definition

injection of PGF2 alpha terminate unwanted pregnancy up to 120-150 days but is not 100% reliable

should see abortion or return to oestrous within 3-5 days. 

 

Term
Stages and causes of pregnancy loss in cattle
Definition

early embryonic death before day 19 is common. 

after service, the cow must recognise she is pregnany by day 16 to prevent luteolysis. Interferon-tau is secreted from blastocyst >15mm diameter normally by Day 15 until around Day 20. 

Term
Interferon tau
Definition
antiluteolytic properties as it inhibits oxytocin receptor ( OTR) expression in the endometrium which prevents prostaglandin production by the endometrium and therefore prevents luteolysis.
Term
Causes of pregnancy loss and when they occur
Definition
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Term
Foetal death in Utero, Later in pregnancy
Definition

events following foetal death in utero depend on

- cause of death

- stage of pregnancy

- other foetal/maternal factors

 

Term
Mummification
Definition

foetal death in utero, persistence of CL, cervix remains closed, uterine contractions absent. 

CAN ONLY TAKE PLACE WHEN FOETUS DIES WELL BEFORE TIME OF EXPULSION OR REMOVAL- TIME CONSUMING PROCESS

- two types occur: 

1. papyraceous

2. haematic 

Term
Papyraceous mummification
Definition

parchment like 

- after foetal death, all foetal fluids are slowly reabsorbed ( amniotic, allantoic, intra-extra cellular. foetus becomes a dried friable contorted mass surrounded by parchment-like membranes. 

Term
haematic mummification
Definition

said to be more common than papyraceous

- was associated principally with channel island breeds but also recognised in others

- 3-8 months ( usually 5-7) gestation

- haemorrhage from placentomes between endometrium and chorion follows foetal death. blood degenerates into a viscous brown material 

Term
Diagnosis of mummification
Definition

- late pregnancy/beyond term

- per rectum exam- small hard uterus at or anterior to the pelvic brim. 

- no placentomes

- no foetal fluids

- no fremitus

If uterus is over pelvic brim and not able to be retracted then blood sample for oestrone sulphate ( indicates placental function) and or Pregnancy specific protein B ( PSPB) will confirm absence of viable foetus

- occasionally luteal regression after mummification occurs- can be manually removed. 

If luteal regression occurs, and cervix dilates but mummy remains in utero, maceration follows. 

Term
Treatment of mummification
Definition

injection with PGF2alpha can be tried to lyse CL and cause expulsion of mummy. 

- in most cases mummified calf may be pushed into cervix/vagina but require manual assistance to remove. ( NB. corticosteroids ineffecetive when a dead foetus is present . if PGF2alpha treatment fails then cow may need culled for infertility. 

Term
Maceration
Definition

sequel to foetal death in utero without expulsion

following foetal death, CL regresses, parturient process begins, but failts to run its course

- bacteria enter the dilated cervix and by putrifaction and autolysis the soft tissues regress until a compact mass of bones remain

- discharge from vulva

- exam per rectum- foetal parts palpable

Term
Treatment for maceration
Definition

rarely effective

uterus may be manually emptied of larger bones but smalles ones usually remain and are invariably attached to or embedded within, the endometrium, where they cause residual chronic inflammation and act as an intra uterine contraceptive device. 

Term
Pyometra
Definition

most cases follow parturition and endometritis

can be a sequel to early pregnancy loss, when CL persists, cervix remains closed cow remains anoestrus. 

 

Term
pre partum metritis end Empysema  ( rotten calf)
Definition

- most commonly encountered in the peri-partum period- notably in cases of neglected ( not necessarily) dystocia

- uterine infection by gas producing bacteria which usually gain access via the cervix. uterine cntents provide an ideal medium for bacterial growth. 

- a dead foetus in utero can be emphysematous without intially causing maternal ill health. 

- toxaemia renders the dam acutely ill, the condition may be rapidly fatal 

clinical signs: 

depending on toxaemia, can be depressed, signs of dehydration, foetid vaginal discharge, occasional straining 

Term
Diagnosis of peri partum metritis and emphysema
Definition

confirmed by vaginal exam, 

ideally use lots of lube and remove calf intact by traction

partial fetotomy may be required but may be hard to remove all of calf as can be dry and clamped in uterine horns

- caesarian section may be preferable to fetotomy, but must be balanced against state of dam

- NSAIDS and fluids

- euthanasia sometimes needed 

Term
hydramnios
Definition

rare than hydrallantois

gradual accumulation of excess volume of amniotic fluid around mid late trimester

- caused by foetal abnormality imparing ability to swallow fluids

clinical signs: abdominal distension, may have excess fluid when amnion ruptures

 

Term
Hydrallantois
Definition

severe abdominal distension in last trimester associated with massive volume of allantoic fluid. Cow has distended pear-shaped abdomen when viewed from rear. 

can lead to increased appetite, weakness and recumbancy

- rectal palpation may reveal distended fluid filled uterus but foetus and placentomes often not palpable. 

abdominal ultrasound and paracentesis will confirm diagnosis and differentiate from ascites. 

treatment: humane distruction should be considered

- if cases are ID early enough, then aim is to monitor the wellbeing of the cow and induce parturition as soon as the ow deteriorates. 

Term
hydrocephalus
Definition
arises because of interference with normal circulation of CSF, usually secondary to cranio-facial foetal deformities. occasional cause of dystocia. most cases  unknown why
Term
foetal anasarca
Definition

grossly oversized foetus may be aborted, upto 3X normal birth weight. excessive subcutaneous fluid distorting whole body will cause dystocia

 - autosomal recessive gene

- mild hyrdallantois and oedema of the foetal membranes may accompany foetal anasarca

Term
Foetal ascites
Definition

gross accumulation of fluid, within the body cavities. 

may occur in any breed

- often associated with achondroplasia

will often cause dystocia with calf getting stuck at shoulders as abdomen too distended to enter pelvis. 

partial fetotomy can allow puncture of diaphragm and drainage of fluid via thorax or incision of abdomen with guarded knife. C section may be needed

Term
schistosoma reflexus
Definition
common foetal monster. foetus is presented with 4 feet or intestines at vagina of dam and may require partial embryotomy of C section
Term

involvement of uterus in a ventral hernia

 

Definition

can be due to muscle weakness, debility, trauma, rupture associated with hydrallantois. 

- ventral hernia arise lateral to midline, only a gravid uterus will enter a ventral hernia

- can see progressively larger swelling apparently in midline, greatest between hindlimbs. 

ddx: early stages may need differentiating from haematoma, abscess and pre partum oedema

- cull if severe concurrent injuries present. if not, aim to treat conservatively until calving. will need assistance at calving. 

Term
Prolapse of the vagina / cervix
Definition

most commonly as sporadic problem. 

- most commonly in older beef cows in late pregnancy

- cause: combination of overcondition, abnormal relaxation of pelvic ligaments associated with increased oestrogen levels. 

CS: prolapse, can become infected and irritated

Treatment: slight prolapse: keep under observation until cow calves when problem will self cure

severe prolapse: may need salvage slaughter, or a C section might save the calf 

But between these extremes, most can be replaced and retained until calving

Term
replacing a prolapsed vagina/ cervix
Definition

1. give caudal epidural- 5-8ml lignocaine

2. clean perineaum and prolapsed tissue

3. lube and replace prolapse by steady manual pressure

4. drain urine via a needle by puncturing the vaginal wall may help. 

5. check replacement is correct

6. give ab and NSAIDS to cover if vaginitis present

7. select method for retaining prolapse

ie. trusses and harnesses or sutures 

 

Term
Buhner's suture
Definition

placed in peri vulval tissue, non absorbable

is a modified purse string suture, least traumatic, best tolerated, doesnt induce straining. 

nylon tape as suture

sutures must be removed at start of parturition or severe perineal tearing can occur. 

Term
surgical methods for prolapses
Definition
Robert's modification of Caslick's operation and Farquharsons techniwue have been described.
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