Diseases of pregnancy in the mare Flashcards
Differential diagnoses of colic (8)
- Abortion/premature parturition
- Uterine torsion
- Fetal hypermotility
- Uterine dorsoretroflexion
- Hydrops of the placental membranes
- Uterine rupture
- Pre-pubic tendon / abdominal muscle rupture
- Colic of non-genital tract origin
Differential diagnoses of premature mammary gland development and lactation (6)
- Placentitis
- Chronic placental separation
- In utero death of a twin
- Impending abortion
- Idiopathic abortion
- ‘Running milk’
Differential diagnoses of vulval discharge (5)
- Placentitis
- Placental separation
- Vaginitis
- Urine staining
- Varicose veins
Differential diagnoses of ventral oedema/abdominal swelling (4)
- Hydrops
- Pre-pubic tendon/abdominal wall muscle rupture
- Mammary gland oedema
- Late pregnancy
Other abnormalities of pregnancy
- Hyperlipidaemia
- Orthopaedic problems
- Oestrus behaviour
- Prolonged gestation
- Rarely immune-mediated thrombocytopaenia (ITP) and Evan’s syndrome
Mammary gland development
- 2 mammary glands, each with two small openings
- Growth begins about a month before parturition
- Most size increase in two weeks beforehand
- Teats become shorter and fatter as udder becomes full as bases are stretched
- Oedema of udder and ventral body wall are indications of full term
- White flecks seen on teats a few days before waxing up
- Wax up 24 hrs before birth
Mammary secretion
Typically mammary secretions pass from straw colour water like secretions to more cloudy in the weeks preceding parturition
Colostrum is yellowish white and viscous
Perineal conformation/relaxation
Relaxation of pelvic ligaments and softening either side of tail head several days before parturition to allow expansion of birth canal
Vaginoscopy
In first 10 months of pregnancy vagina should be tight, tacky, and cervix tight and pale with a mucus plug
Transrectal ultrasound
5.0 or 7.5 MHz linear transducer
To measure the combined thickness of the uteroplacental junction just cranial to the cervical os to be measured
Abnormal thickening may be indicative of placentitis while increased echogenicity of the uterine fluid may follow haemorrhage, meconium release or inflammatory debris which
Transabdominal ultrasound
Enables assessment of maturity and viability of the pregnancy
Further placental assessment, foetal fluids, foetal movement and position, foetal heart rate, and foetal size and growth
Parameters measures in the blood
- eCG: early gestation, confirms presence of placenta only
- Oestrone sulphate: mid gestation, ocnfirms presence of live foetus (produced by foetal gonads)
- Progesterone
Abortion/premature parturition
Mild/moderate colic
Restlessness, sweating, raised tailhead
Usually little or no mammary gland development
Dry vulva, but vagina is moist and pink
Cervical plug will have liquefied
Allantochorion membranes may be visible with or without a bloody or purulent discharge
No effective treatment - just monitor and help with dystocia if it occurs
Isolate, burn bedding and placental membranes, and submit foetus to a lab
Uterine torsion
Often in late gestation (7mo-term)
Older mares more susceptible
Early intervention important
Varied signs from low grade colic to severe colic unresponsive to analgesic
Diagnose via palpation of broad ligaments per rectum
Treat by rolling or laparotomy
Fetal hypermotility
Mild colic in late pregnancy
Violent and excessive fetal movement of unknown cause
Treat with smooth muscle spasmolytics or tocolytics but if it persists assess with transabdominal US
Uterine dorsoretroflexion
Seen in last third of pregnancy
Moderate to severe colic
Straining to pass faeces
Swelling may be visible around vulva and perineum due to fetal impaction in pelvic canal
Cause unknown
Diagnose with rectal palpation - live fetus palpable in birth canal enclosed in tight uterus
Treat with smooth muscle relaxant drugs, reduce food intake and encourage regular walking
Hydrops of the placental membranes
Large physiological volumes of fluid (up to 100L) may accumulate before clinical signs become apparent, then up to 250L
Uncommon and cause unknown
Usually multiparous mares and hydroallantois is most likely
Signs are acute onset, rapid excessive abdominal distension in last third of pregnancy
Progressive condition, few reach term and produce a live foal, most abort spontaneously
Can be rebred successfully
Uterine rupture
Usually post-foaling period but may occur secondary to uterine torsion, hydrops allantois and twins
Mild to moderate colic signs dependent on extent of rupture and peritoneal inflammation
Diagnosis on rectal palpation
Occasionally haemorrhage and exsanguination can be fatal
Foal may be free within the abdomen
Prepubic tendon/abdominal muscle rupture
In late gestation
Tearing of the prepubic tendon where it inserts onto pelvis, or of the central abdominal musculature
Acute onset with a discrete bulge on ventral aspect, painful to palpate, oedema does not disappear with exercise
Treatment is variable and dependent on extent of rupture - premature parturition, belly band, etc.
Further breeding not advisable
Placentitis
Cervix open and draining pus
Accelerates fetal maturation, so increased viability of the foal is possible
Treat with systemic antibiotics, normally only trimethoprim cross the placenta to fetal circulation
Chronic placental separation
Insidious onset
May be the result of an underlying abnormality within the fetoplacental unit
Separation begins at the cervical star, cervix softens and opens
Treatment may include antibiotics, anti-inflammatories, clenbuterol, and progesterone
Acute premature placental separation
‘Red bag’
During second stage labour
Treatment may include antibiotics, anti-inflammatories, clenbuterol, and progesterone
Impending abortion
Usually no mammary gland development due to acute nature of the event
‘Running milk’
Premature secretion of milk
Can occur up to several weeks before foaling
Leads to failure of passive transfer
