Segmental Hypoplasia of the Spinal Cord in a Japanese Black Calf

Abstract

ABSTRACT. Segmental hypoplasia not associated with vertebral abnormalities was found in a Japanese Black calf that was unable to stand. Constriction occurred between the third and 5th segments of the lumbar spinal cord, and was most severe in the 4th segment. Myelodysplasia, such as hydromyelia and syringomyelia, absence or interruption of the central canal, dysplasia of the gray matter, and absence or divergence of the septal connective tissue at the dorsal median septum or the ventral median fissure, were confirmed histologically. These changes indicate hypoplasia of the segments affected following neural tube closure. Therefore, this case was suspected to be a closed neural tube defect. KEY WORDS: Japanese Black calf, myelodysplasia, segmental hypoplasia of the spinal cord.J. Vet. Med. Sci. 71(3): 337-340, 2009 Congenital abnormalities of the spinal cord have been described collectively as myelodysplasia or dysraphic states [7,10]. In cattle, the occurrence of spina bifida, a spinal neural tube closure defect, is common [8]. Hypoplasia of the spinal cord is defined as a reduced development of one or more segments of the spinal cord [10]. In cattle, this hypoplasia has been reported in Angus and other breeds [7,8]. Although these reports described only the brief clinical signs of the affected animal [8], abnormalities in appearance, pathological changes and other details of the animals were not reported. Constriction or absence of the spinal cord have always been associated with vertebral abnormalities such as segmental aplasia of the spinal cord [4,9], perosomus elumbis [6] and spinal stenosis [3].In this study, we describe a rare anomaly of the spinal cord, namely, segmental hypoplasia of the spinal cord in a calf that was not associated with vertebral abnormalities. The morphological changes of the malformed spinal cord were examined, and their pathogenesis was discussed from an embryological viewpoint. The subject was a male Japanese Black calf that was unable to stand after birth. His left forelimb and right hindlimb were not flexible and exhibited only mild convulsion. In general appearance, spinal defects could not be confirmed. Although the calf was born 2 weeks before the expected delivery date, the general conditions, such as vigor and appetite, were fine. The calf was euthanized after one month according to the request of the owner of the animal, and a postmortem examination was performed. The weight of the calf before the necropsy was 42 kg, indicating a reduced growth compared to normal calves. It was the first delivery of the cow, which went through a normal pregnancy and did not receive the administration of any drugs. No similar cases have been reported from the maternal or paternal line of the calf.The necropsy confirmed a constriction between the third (L3) and fifth (L5) segments of the lumbar spinal cord, with the constriction in the fourth segment (L4) being the most severe (diameter: approx. 6 mm) (Fig. 1). Despite a mild dorsal curvature of the spine, no spinal canal narrowing or abno...

Congenital Segmental Hypoplasia of the Spinal Cord in A Holstein Calf

“…Generally vertebral defects are detected in cows with segmental hypoplasia defect of spinal cord [5] . In cases like …”

“…In cattle, those hypoplasia have been previously reported in Angus and other breeds [3,4] . Genetic and nutritional factors, environmental factors like infections and toxins together with fertilization techniques have been shown as common reasons of congenital malformations [5,6] . [4,6] .…”

“…Previously, cavitations of the spinal cord without vertebral defect were reported in spinal dysraphisms of cervical spinal cord [9,10] and in syringomyelia of thoracic spinal cord [5,10] . Likewise in the cranial part of hypoplastic medulla spinalis we detected a cavitation approximately 1-2 mm without any defect in vertebras.…”

Syringomyelia in a Newborn Male Simmental Calf

“…Congenital malformations affecting the cerebellum, such as Chiari‐like malformation with displacement of the cerebellum through the foramen magnum, or Dandy‐Walker syndrome with cerebellar hypoplasia, cysts in the fourth ventricle and hydrocephalus often occur in combination with syringohydromyelia. Other congenital disorders affecting the spinal cord are described in the literature,12 from spinal dysraphism,13 spina bifida and spinal dysraphism,14 segmental aplasia of the cord15 and segmental hypoplasia 16…”

Recurrent Outbreaks of Myelodysplasia in Newborn Calves

“…There are few reports of this pathological change in cattle and these were isolated cases that affected only a small number of animals and were often associated with skeletal deformities, cleft palate and arthrogryposis (Leipold et al, 1977(Leipold et al, , 1993Hiraga and Abe, 1987;Doige et al, 1990;Ohfuji, 1999;Imai and Moritomo, 2009;Hill, 2010). Myelodysplasia has been related to genetic factors in Charolais and Hereford calves, although the mode of inheritance is unknown (Leipold et al, 1969).…”