Calving-related intradural avulsion injuries of the thoracolumbar spinal nerve roots in a calf.

Calving difficulty may lead to traumatic peripheral nerve injury. A male, 8-mo-old, Japanese Black calf with a history of secondary dystocia as a result of fetal gigantism had lameness and gait disturbance. At autopsy, multifocal dural thickening with adhesions to the adjacent spinal cord was observed at T12-13 and L4-5 vertebral levels. Microscopically, numerous traumatic neuroma-like fascicles of nerve twigs were embedded in the dura mater with abundant collagenous connective tissue. By immunohistochemistry, axons and Schwann cells were confirmed in each nerve fascicle. Our observations suggest that avulsion injuries in the preganglionic fibers of the spinal nerve roots, and secondary spinal cord compression, resulted in the development of neurologic signs.

Partial costectomy for tracheal collapse and stenosis associated with perinatal rib fracture in three Japanese Black calves.

2.3-month-old (Case 1), one-month-old (Case 2) and 6-month-old (Case 3), Japanese Black calves presented with mild to severe wheezing. All calves had histories of dystocia at birth with breech presentation. Physical examination, thoracic radiography, endoscopy or computed tomography indicated wheezing associated with tracheal collapse and stenosis caused by perinatal rib fractures. Partial resection of the fractured first and second ribs was performed on all calves. The respiration in Cases 1 and 2 immediately improved after the surgery, while Case 3 required two weeks to improve. Cases 1 and 3 grew up healthy and were sold at auction, but Case 2 had a recurrence of wheezing at three months post-discharge and showed growth retarding. Partial costectomy may be an effective solution for control of respiration, however, further cases are required to discuss the criteria for surgical management and to obtain favorable postoperative prognosis in calves with tracheal collapse and stenosis caused by perinatal rib fractures.

Extraction forces in bovine obstetrics: an in vitro study investigating alternate and simultaneous traction modes.

Whether extraction of a calf in longitudinal anterior presentation should be carried out by simultaneous or alternate traction on the forelimbs remains controversial. Because most recommendations are based on empirical observations rather than on scientific studies, the aim of this study was to develop an in vitro model to objectively compare the forces occurring during alternate and simultaneous traction. In a biomechanical in vitro model, 12 dead Holstein-Friesian (Bos taurus) calves were pulled through the prepared pelvic specimen of a cow at a controlled speed using two electric motors. Traction was applied simultaneously (ST) to both legs or alternately (AT) to one leg at a time to advance the calf 5 cm (AT 5) or 10 cm (AT 10). Forces on each limb were measured digitally using load cells. In all cases, two peaks of maximum force occurred during the extraction of the cranial part of the body. The first peak was observed when the elbows were pulled into the pelvis, and the second peak occurred when the chest emerged from the pelvis. Up to and including entry of the elbows into the pelvis, the maximum force on a single limb (341+/-106 N) was lowest (P<0.01) using AT10. The maximum traction forces acting on a single limb using AT5 (411+/-86 N) and ST (431+/-127 N) did not differ (P>0.05). During extraction of the thorax, the maximum force acting on a single limb was lower (P<0.0001) using ST (352+/-98 N) compared with AT5 (432+/-79 N) and AT10 (547+/-115 N). Based on these findings, alternate-limb traction, 10 cm at a time, should be used until both elbows have entered the pelvis. Simultaneous traction should then be applied to both forelimbs to complete extraction of the chest.

Lesions in the central nervous system associated with perinatal lamb mortality.

OBJECTIVE: To identify and describe the occurrence of neurological lesions that could have an effect on lamb mortality. PROCEDURE: The central nervous system was investigated macroscopically (n = 92) and microscopically (n = 72) in lambs dying in the perinatal period during 3 years in flocks of adult Corriedale ewes. The central nervous system was removed intact and samples of cerebral cortex, basal ganglia, thalamus, hippocampus, mesencephalon, cerebellar cortex, medulla oblongata, and cervical spinal cord were scored microscopically for the severity of neuronal dead, cytotoxic and perivascular oedema, and haemorrhage. RESULTS: Neurologic findings between birth and 6 days included haemorrhages in meninges, brain congestion and oedema, neuronal ischemic necrosis, intraparenchymal haemorrhages in medulla oblongata and cervical spinal cord, parasagittal cerebral necrosis, and periventricular leukomalacia. No significant lesions were found in anteparturient deaths or in those aged between 7 and 16 days. Oedema was more severe in the brain than in other regions of the central nervous system. Ischaemic neurons first appeared 24 hours post partum, increased linearly in number between 48 hours and 5 days post partum, and had a laminar distribution in the cerebral cortex, indicating a hypoxic-ischemic encephalopathy. Haemorrhages were most severe in the gray matter of medulla oblongata and cervical spinal cord, suggesting trauma due to instability of atlantoaxialis joint. CONCLUSION: Lesions in the central nervous system can explain most deaths at birth and within 6 days of birth. The lesions were hypoxic-ischemic and appeared to be related to birth injury.

Detection of rib trauma in newborn foals in an equine critical care unit: a comparison of ultrasonography, radiography and physical examination.

REASONS FOR PERFORMING STUDY: Previous studies have shown that in man ultrasonography is more accurate than radiography for detecting rib fractures. OBJECTIVES: To describe clinical, radiographic and ultrasonographic findings related with rib fractures in newborn foals in an equine critical care unit; and to compare diagnostic accuracy of ultrasonography to radiography. METHODS: A prospective ultrasonographic study was performed on 29 foals presented to the emergency unit. This study was performed at the Centre Hospitalier Universitaire Vétérinaire (CHUV), University of Montreal. Physical examination as well as radiographic and ultrasonographic examinations were performed. RESULTS: Thoracic radiographs revealed 10 rib fractures in 5 of 26 (19%) foals. Ultrasonography revealed 49 fractures in 19 of 29 (65%) foals of which fillies (n = 13; 68%) were significantly over represented as were fractures to the left thorax (n = 15; 78%). Seventeen of 19 foals (90%) had rib fractures located 3 cm or less from the costochondral junction, the distal part of the rib being displaced laterally in all cases. In 2 foals, where both thoracic radiographs and ultrasonography detected rib fractures, the site of fractures was located on the mid portion of the rib. Rib fractures were detected only by thoracic radiographs in one foal. Sixty-five percent (32/49) of fractured ribs had a moderate displacement (1-4 mm). CONCLUSIONS: Rib fractures are seen frequently in newborn foals in equine critical care units. Ultrasonography is more accurate than radiography and reveals fractures in most patients presented in emergency. The position (costochondral junction) of rib fractures and of the fragments suggest that most thoracic trauma probably occurs during parturition. POTENTIAL RELEVANCE: Ultrasound imaging increases awareness and improves the diagnosis of rib fractures in newborn foals.

Thoracic trauma in foals: post mortem findings.

REASONS FOR PERFORMING STUDY: Thoracic trauma occurs in newborn foals and may cause associated clinical signs; this condition remains poorly documented. OBJECTIVES: The purpose of this study was to describe the pathological features of thoracic trauma in newborn foals presented for necropsy examination between 1990 and 2000. METHODS: Necropsy reports of foals with thoracic trauma from 1990-2000 were reviewed. Subject details, clinical signs, thoracic and abdominal lesions were noted and analysed statistically. RESULTS: Sixty-seven (9%) of 760 necropsied foals had thoracic trauma. In 19 foals, fractured ribs were considered to be the cause of death (Group A). The remaining foals had fractured ribs (Group B, n = 20) or rib contusions (Group C, n = 28) that were incidental findings. Ribs 3 to 8 accounted for 86% of the traumatised bones. The most common site of injury was the costochondral junction and an area immediately above it (94%). In Group A, all but 2 foals died within the first 8 days postpartum. Haemothorax and subsequent pulmonary collapse was cited most commonly as the cause of death (53%). Diaphragmatic rupture and hernia (n = 2) also occurred. CONCLUSIONS: The focal site, consistent location and presence of lesions during the first week post partum, all suggest that thoracic trauma in newborn foals probably occurs during parturition. POTENTIAL RELEVANCE: The description of lesions and site of occurrence of thoracic trauma in foals will increase awareness and improve the diagnosis and treatment of this life threatening condition.

Thoracic trauma in newborn foals.

In a report describing life ending fractures (255 horses) from the Livestock Disease Diagnostic Center, Kentucky (1993 and 1994), 32 foals had rib fractures. The purpose of our study was to examine the incidence of rib fractures in newborn foals on a Thoroughbred studfarm by physical and radiographic examination, to determine factors which may contribute to the problem and to document any clinical consequences. All foals (263) included were examined within 3 days of birth. The thoracic cage was palpated externally for abnormalities and all foals were placed in dorsal recumbency to evaluate thoracic cage symmetry. Radiographs were used to diagnose foals with thoracic cage asymmetry (TCA) and rib fracture (RF). A diagnosis of costochondral dislocation (CD) was made when no radiographic evidence of fracture was present but there was severe TCA. Fifty-five foals (20.1%) had TCA (9 RF). One to 5 ribs were fractured on 9 of 40 radiographic studies. No consequences of the thoracic trauma was detected clinically, radiographically or ultrasonographically in this group of foals or at a 2- and 4-week follow-up examination. The percentage of foals with a history of abnormal parturition was higher in the TCA foals (15%) compared to the normal foals (6.8%). There were more primiparous dams in the TCA group than in the normal foal group. Fillies (56.6%) had a higher incidence of birth trauma than colts (43.4%). This study demonstrates that thoracic trauma is often present in newborn foals and may not always be of clinical significance. Dystocia foals and foals from primiparous mares should be considered high risk for thoracic trauma.

Horner's syndrome in a puppy.

A puppy was presented with unilateral Horner's syndrome thought to have been in existence since the eyes first opened. No other clinical signs were evidence and the condition was attributed to trauma during assisted birth. All abnormalities resolved spontaneously by 11 weeks of age.

Causes of abortion, stillbirth, and perinatal death in horses: 3,527 cases (1986-1991).

Pathology case records of 3,514 aborted fetuses, stillborn foals, or foals that died < 24 hours after birth and of 13 placentas from mares whose foals were weak or unthrifty at birth were reviewed to determine the cause of abortion, death, or illness. Fetoplacental infection caused by bacteria (n = 628), equine herpesvirus (143), fungi (61), or placentitis (351), in which an etiologic agent could not be defined, was the most common diagnosis. Complications of birth, including neonatal asphyxia, dystocia, or trauma, were the second most common cause of mortality and were diagnosed in 19% of the cases (679). Other common diagnoses were placental edema or premature separation of placenta (249), development of twins (221), contracted foal syndrome (188), other congenital anomalies (160), and umbilical cord abnormalities (121). Less common conditions were placental villous atrophy or body pregnancy (81), fetal diarrhea syndrome (34), and neoplasms or miscellaneous conditions (26). A diagnosis was not established in 16% of the cases seen (585). The study revealed that leptospirosis (78) was an important cause of bacterial abortion in mares, and that infection by a nocardioform actinomycete (45) was an important cause of chronic placentitis.

[Birth injuries in calves and perinatal calf losses in a large dairy herd]. / Geburtsschäden an Kälbern und perinatale Kälberverluste in einer grossen Milchrindherde.

Post-mortem examinations were carried out on 65 calves which were stillborn or died within 24 hours of birth. All calves came from a large dairy unit with about one thousand cattle of the Schwarzbuntes Milchrind breed. To evaluate the perinatal losses, the farm records of parturitions from 1985-1990 were used. The calves had gross damage of the CNS, the musculature, subcutaneous tissue and internal organs such as lung and intestines. It may be assumed that a lesser degree of similar damage would also be present in the surviving calves. The level of perinatal losses is determined particularly by deaths following prolonged parturition due to foetal oversize in heifers and young cows, but also by the birth of immature calves of low weight after pregnancy of normal or decreased duration and by twin pregnancies with high total calf mass and relative immaturity of the calves.

[Delivery-induced fracture of the spine in a newborn calf]. / Geburtsbedingte Wirbelsäulenfraktur bei einem neugeborenen Kalb.

The case of a 3 days old calf taken to the local animal hospital with a complete fracture of the vertebral column at the transitory point between thoracic and lumbar spine is reported. The fracture could be attributed to the wrong use of a mechanical fetal extractor, which is a common mistake when using it for forced extraction.