Hereditary neuraxial oedema in a Poll Hereford herd

Cases of neuraxial oedema in a Poll Hereford herd were investigated and the pedigrees of affected calves determined. In all cases, and over no more than 3 generations, the pedigree led back to a common bull. Analysis of the herd breeding records supported an autosomal recessive mode of inheritance of the disease. Fractures of the femoral heads, acetabular cartilage and/ or bone, or both, were seen in some affected calves. This lesion was probably induced during birth or soon after, and the suggestion is made that such hip lesions could be regarded as highly suggestive of hereditary neuraxial oedmea of Herefords. The majority of calves showed clinical signs at birth, but 2 calves did not develop clinical signs until they were 2 days old.     

Spastic syndrome in a Canadian Hereford bull.

A 3-1/2-year-old Canadian Hereford bull was diagnosed with spastic syndrome. The disease had not been reported previously in Canadian Herefords and, in this case, it had a strong familial component with a relatively early age of onset (1 to 2 years). Signs of the disease were exacerbated while the bull was housed indoors.     

Pathogenesis of psoroptic scabies in Hereford heifer calves

Hereford heifer calves were experimentally infested with Psoroptes ovis. Histologic examination of skin specimens was conducted at weekly intervals before and after treatment with ivermectin on postinfestation week 7. Electron microscopy revealed numerous degranulating mast cells in the skin of infested but not in control calves. many active, as well as degenerate, neutrophils were in the scab on infested calves. Microscopic epidermal ulcers developed on infested calves when live mites were present but not after treatment. Numbers of dermal neutrophils and plasma cells decreased and numbers of circulating neutrophils increased 1 week after treatment. Numbers of dermal eosinophils and mast cells in calves with eosinophilia increased for several weeks after treatment. Statistical analysis indicated significant correlations (P less than 0.05) among numbers of dermal inflammatory cells, hemogram values, and changes in dermal thickness. Seemingly, mite-induced epidermal damage was the key pathogenic event in psoroptic scabies in calves. Mast cell degranulation contributed to the pathogenesis of the dermatitis, and neutropenia was caused by sustained, poorly compensated efflux of neutrophils into the scab through mite-induced breaks in the epidermis.     

Cardiomyopathy associated with a curly hair coat in Poll Hereford calves in Australia

Fifteen newborn Poll Hereford calves from five farms died over a three-and-a-half year period. From birth all calves had a tight, curly hair coat which was not observed on any other calves on these properties. All calves with this phenotype died before reaching six months of age. Seven of the 15 calves were noticed to have exercise intolerance, hyperpnoea and dyspnoea for one to seven days before death. The incidence of additional features of the curly hair coat phenotype is also described. Post mortem examinations conducted on the calves revealed focal, diffuse and pale fibrous streaking of the entire myocardium and vascular congestion of the livers, spleens and lungs. A primary cardiomyopathy was diagnosed on the basis of the clinical and pathological findings. Analysis of the pedigrees of seven affected calves from one farm demonstrated a common ancestor for all sires and dams of affected calves and suggested a simple autosomal recessive mode of inheritance of the syndrome as a reasonable hypothesis for future experimental testing.     

Congenital dyserythropoietic anaemia and dyskeratosis in Australian Poll Hereford calves

Congenital dyserythropoietic anaemia (CDA) is a heterogeneous group of rare genetic disorders that in humans is characterised by ineffective haematopoiesis with morphological abnormalities in erythroid precursor cells and secondary iron overload. In the 1990s, a syndrome of CDA with dyskeratosis and progressive alopecia was reported in Poll Hereford calves in Canada and the USA. We report the clinical and pathological findings in two Poll Hereford calves with this syndrome from separate properties in South Australia. The animals had a variably severe anaemia, associated with abnormal nucleated red blood cells in peripheral blood, and large numbers of rubricytes and metarubricytes with a characteristic nuclear ultrastructure in the bone marrow. Both calves were born with a wiry hair coat and a progressively ‘dirty‐faced’ appearance associated with hyperkeratosis and dyskeratosis (apoptosis).     

Additive genetic relationships between heifer pregnancy and scrotal circumference in Hereford cattle.

The objective of this study was to determine an appropriate method for using yearling scrotal circumference observations and heifer pregnancy observations to produce EPD for heifer pregnancy. We determined the additive genetic effects of and relationship between scrotal circumference and heifer pregnancy for a herd of Hereford cattle in Solano, New Mexico. The binary trait of heifer pregnancy was defined as the probability of a heifer conceiving and remaining pregnant to 120 d, given that she was exposed at breeding. Estimates of heritability for heifer pregnancy and scrotal circumference were .138+/-.08 and .714+/-.132, respectively. Estimates of fixed effects for age of dam and age were significant for heifer pregnancy and bull scrotal circumference. The estimate of the additive genetic correlation between yearling heifer pregnancy and yearling bull scrotal circumference was .002+/-.45. Additional analyses included models with additive genetic groups for scrotal circumference EPD for heifer pregnancy or heifer pregnancy EPD for scrotal circumference to account for a potential nonlinear relationship between scrotal circumference and heifer pregnancy. Results support the development of a heifer pregnancy EPD because of a higher estimated heritability than previously reported. The development of a heifer pregnancy EPD would be an additional method for improving genetic merit for heifer fertility.     

Thymic lymphosarcoma with metastases causing spinal cord compression and pelvic limb paresis in a heifer

Neurological examination of a heifer displaying pelvic limb ataxia and paresis progressing to a dog-sit position but with normal thoracic limb function indicated a spinal cord lesion in the low thoracic/high lumbar region. The progressive neurological deterioration despite normal radiological and cerebrospinal fluid findings were suggestive of a non-inflammatory, non-traumatic extradural compressive lesion; this was subsequently shown to be a lymphosarcoma.     

Prenatal occurrence and mode of inheritance of neuraxial oedema in Poll Hereford calves

Breeding experiments were conducted in 1981, 1982 and 1983 using bulls and cows that were obligatory heterozygotes for neuraxial oedema. Fifty-six calves were born in the herd, 14 of which were diagnosed as cases of neuraxial oedema. The mean gestation length for affected calves born in 1983 was nine days shorter than that for unaffected calves. Observations were made of the birth of three affected calves. In one calf spasms of the forelimbs were observed during an unassisted delivery, and in this and two others, typical clinical signs were observed within two minutes of birth. Radiological and, or, pathological examination of each of the eight affected calves born in 1983 revealed lesions in the coxae, some of which predated parturition. These observations are consistent with the calves being affected with neuraxial oedema while in utero.     

Cardiomyopathy and woolly haircoat syndrome of Poll Hereford cattle: electrocardiographic findings in affected and unaffected calves

Electrocardiograms were recorded from 4 calves with cardiomyopathy and woolly haircoat syndrome (CWH), a lethal autosomal recessive trait of Poll Hereford cattle and from 9 unaffected calves. Electrocardiograms of calves with CWH were characterised by multifocal ventricular premature contractions which occurred singly, in pairs, in runs and as episodes of ventricular tachycardia. Bigeminal rhythms were recorded occasionally. The frequency of ventricular premature contractions ranged from 5 to 120.min-1. Ventricular premature contractions in calves with CWH were attributed to myocardial degeneration and fibrosis which were observed grossly and microscopically. Electrocardiograms in unaffected calves were characterised by normal sinus rhythm and by variation in the morphology of wave forms between animals. The durations of the various wave forms were less than those previously recorded from adult cattle.     

Autosomal trisomy in a heifer

A malformed Ayrshire heifer had one additional autosome in all the lymphocyte metaphases studied. Chromosome banding techniques showed the karyotype of the calf to be 2n = 61, XX, +24.Slight prognathia of the lower jaw and peculiar abbrevations in the structure of the genitals were the most apparent anomalies, in addition to heart abnormalities, a poorly-closed urachus and slow growth rate.     

Melanosis in a Holstein heifer

A case of Melanosis in a Holstein heifer is described in this report. Many of the visceral organs, diaphragm and skeletal muscles have got dark-brown to black and diffuse pigmentation in different diameters on their surfaces and cuts. Microscopically, brown to black coloured pigment containing cells were detected in the heart, lung, liver, spleen and muscle tissues. After depigmentation process, it was seen that the normal histological structure of the organ disappeared in these pigmented region. There were large, vesicular and macrophage-like cells with small nuclei. In immunohistochemical staining, HMB45 was strongly positive in many tissues.