Tethered spinal cord related to caudal spinal dysraphism in a tailless Holstein calf.

A rare dysraphic caudal spinal anomaly, or caudal agenesis, comprising a tethered spinal cord, was found in a tailless Holstein calf that presented ataxia and paresis with analgesia of the hind limbs. The gently and slimly tapered conus medullaris was poorly formed between S2 and S3 which indicated that it was lying more caudally. The caudal end of the filum terminale adhered to the inner periosteum of the vertebral arch at S4, which is compatible with tethering of the spinal cord. The dysraphic changes from the secondary neurulation error and the longitudinal deranged cord morphology that may have been caused by the caudad traction due to tethering were confirmed. This represents the first bovine case with definitive morphological confirmation.

Segmental spinal dysgenesis with caudal agenesis in a Holstein calf.

A rare complex dysraphic malformation, comprising segmental spinal dysgenesis with caudal agenesis, was found in a Holstein calf that was unable to stand and was slightly short at the lumbosacral spine with taillessness. The thoracolumbar and sacrococcygeal regions of the midline axial segments showed severe deformities. In the spinal cord, the thoracolumbar region showed severe constriction with myelodysplastic changes, and the sacrococcygeal region showed dorsoventral separation with connection to a neural mass. In the spine, vertebral anomalies according to the degree of the segmentation error were confirmed. The cervical and thoracic segments also showed milder dysraphic changes. These changes suggest a multisegmental causal insult impairing the early embryonic notochord. This represents the first bovine case definitively confirmed morphologically.

Accumulation of xanthophylls from the phaffia yeast (Xanthophyllomyces dendrorhrous) in calves.

An investigation into the absorption and accumulation of carotenoids from phaffia yeast in two to three-week-old calves was carried out. Carotenoid contents of the control cattle (n=1) were 615.0 ng/g in the liver, 263.7 ng/g in the duodenum, 218.0 ng/g in the pancreas, 170.0 ng/g in the blood, 140.3 ng/g in the jejunum, 115.0 ng/g in the spleen. Among the accumulated carotenoids, ß-carotene was presented as a major component (86.0 to 94.3%) along with lutein (5.7 to 14.0%) as a minor component. On the other hand, carotenoid contents in phaffia yeast-supplemented (5 g/day for one month) calves (n=3) were 4 to 10 times higher than those of the control calf. Carotenoid contents of phaffia yeast-supplemented calves were 2570.1±782 ng/g in the liver, 1806.6±1064 ng/g in the pancreas, 1648.4±630.2 ng/g in the spleen, and 1255.9±300.2 ng/g in the blood. In addition to ß-carotene, keto-carotenoids from phaffia yeast, echinenone, (3R)-3-hydroxyechinenone, and (3R,3'R)-astaxanthin, were accumulated in all organs of phaffia yeast-supplemented calves. ß-Carotene and (3R)-3-hydroxyechinenone were present as major carotenoids followed by echinenone. However, (3R,3'R)-astaxanthin, which was the major carotenoid in phaffia yeast, was found to be a minor carotenoid in calves. This indicated that calves well absorbed fewer polar xanthophylls, echinenone and (3R)-3-hydroxyechinenone compared to the polar xanthophyll, astaxanthin.

Segmental hypoplasia of the spinal cord in a Japanese black calf.

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.

Clinical and pathological aspects of hemophilia a in Japanese Brown cattle.

A coagulopathy with subcutaneous bleeding and muscular or peritracheal/periesophageal bleeding occurred in two male Japanese Brown calves of the same dam. One of the affected calves died three days after the onset of bleeding and the other survived normally until being slaughtered despite once suffering from subcutaneous hematoma. Hemostatic tests of the latter case showed prolonged activated partial thromboplastin time (APTT), and severely reduced factor VIII activity. In addition, von Willebrand factor activity, determined by the human platelet aggregation test, was within the normal range; therefore, the calf was diagnosed with hemophilia A. These are the first bovine cases of hemophilia A definitely diagnosed clinicopathologically.

Morphological observations of uterine and vaginal duplexes with a developmental anomaly at the vaginovestibular junction in a Japanese brown calf.

Since a rare anomaly of the female genital tract was defined as uterine and vaginal duplexes with a developmental anomaly at the vaginovestibular junction, it was morphologically examined in detail in a Japanese Brown calf. The genital tract was completely duplicated from the uterus to the vagina just cranial to the vestibule. At the vaginovestibular junction, a hymenal constriction and an aberrant location of the outer urethral orifice were also observed. These anomalies suggest that an error in the complete fusion of the Mullerian ducts and a failure in the correlated development between the Mullerian ducts and the urogenital sinus occurred in the embryonic stage.

Positional cloning of the gene LIMBIN responsible for bovine chondrodysplastic dwarfism.

Chondrodysplastic dwarfism in Japanese brown cattle is an autosomal recessive disorder characterized by short limbs. Previously, we mapped the locus responsible for the disease on the distal end of bovine chromosome 6. Here, we narrowed the critical region to approximately 2 cM by using linkage analysis, constructed a BAC and YAC contig covering this region, and identified a gene, LIMBIN (LBN), that possessed disease-specific mutations in the affected calves. One mutation was a single nucleotide substitution leading to an activation of a cryptic splicing donor site and the other was a one-base deletion resulting in a frameshift mutation. Strong expression of the Lbn gene was observed in limb buds of developing mouse embryos and in proliferating chondrocytes and bone-forming osteoblasts in long bones. These findings indicate that LBN is responsible for bovine chondrodysplastic dwarfism and has a critical role in a skeletal development.