Renal dysplasia and nephrosclerosis in calves

Renal dysplasia and nephrosclerosis in six calves, which were aged three to six months and from different farms in western Scotland and north-west England, was characterised clinically by stunted growth and renal failure with uraemia. Affected animals were depressed and one case exhibited severe neurological signs. Reduced erythrocyte counts were evident in three of four animals from which blood samples were submitted for haematology. At postmortem examination, the kidneys were bilaterally small, pale and firm, with marked fibrosis and sometimes contraction of the capsule. Histologically, affected calves had disorganised atrophic glomeruli, dilatation of tubules, loss of nephrons, areas of undifferentiated mesenchyme and diffuse interstitial and periglomerular fibrosis. There was minimal inflammation. Renal dysplasia and nephrosclerosis is a form of juvenile nephropathy of unknown aetiology that occurs sporadically in calves in the UK.

Clinicopathological presentation of cardiac disease in cattle and its impact on decision making

The records of 116 cattle suffering from cardiac disease were examined retrospectively. On the basis of the results of postmortem examinations there were 52 cases of endocarditis, 39 of pericarditis and 25 congenital cardiac defects. The most useful clinical tool for differentiating between these conditions was auscultation of the heart. The cases of pericarditis were characterised by muffled heart sounds, and the cases of endocarditis and congenital cardiac defects were characterised by a cardiac murmur. Endocarditis could be differentiated from congenital cardiac defects by the presence of a jugular pulse, venous distension, oedema, a reduced appetite, pain and polyarthritis, whereas congenital defects were associated with conformational abnormalities. These two conditions could also be differentiated by differences in the plasma sodium concentration, the albumin:globulin ratio, red blood cell count, lymphocyte count and haematocrit. The ability to differentiate between these three groups of cardiac diseases can help the veterinary practitioner in deciding whether treatment, economic salvage (slaughter for human consumption) or disposal (slaughter not for human consumption) is likely to be the best option.

Detection of genes with moderate effects on disease resistance using ovine mhc and resistance to nematodes as an example

Detecting some of the genes that influence disease resistance would improve our understanding of the processes that cause disease and also simplify disease control. Genes within the major histocompatibility complex (mhc) are strong candidates for disease resistance and they have been intensely studied for the last 30 years. Recently, several groups working independently have reported the existence of alleles within the mhc that are associated with enhanced resistance to nematode infection. This article uses hindsight to describe some of the potential pitfalls that hinder the search for valid disease resistance genes. The search requires a good understanding of disease biology, molecular genetics, statistical genetics and especially, the design and analysis of experiments. The power to detect mhc effects is quite low and is quite sensitive to the frequency of the putative resistance alleles.