Assessment of organoleptic postmortem inspection techniques for bovine offal

Prevalence of renal lesions in slaughtered cattle in Shiraz, Iran, and detection of Leptospira in them by nested PCR-RFLP

Renal diseases in cattle are frequently not recognized due to the subclinical conditions. Some species of Leptospira are the main cause of infectious agents that damage the kidneys and lead to abortion and economic losses in cattle and are also of major concern in the public health. This study was aimed to assess the prevalence of renal lesions of slaughtered cattle in the Shiraz abattoir and to determine the correlation between rejected kidneys and infection with Leptospira using nested PCR-restriction fragment length polymorphism (RFLP) techniques. Out of 1000 inspected animals, 205 (20.5 %) revealed the renal lesions. Chronic nephritis (7.5 %), white-spotted kidney (7.3 %), and petechial hemorrhage (3.5 %) were the most prevalent forms of the lesions. A direct correlation between increasing the age and significant increase in the rate of lesions was also observed (P = 0.03). Using nested PCR-RFLP assay, 40.8 % of the tested kidneys were turned to be infected to the pathogenic species of Leptospira. The risk of infection of the kidneys with white spot to pathogenic species of Leptospira (53.8 %) was more than that of the kidneys with other lesions (25.0 %) (P = 0.014). The odd ratio indicates that the kidneys with white spot lesions are likely to be infected with pathogenic species of Leptospira, five times greater than other lesions. This study showed that renal lesions especially white-spotted kidney, which were considerably associated with Leptospira in slaughtered cattle in Shiraz, were very high. This is important in terms of public health and in particular, increases the risk of transmission of disease to human specially in the high-risk careers including farmers, veterinarians, and abattoir workers.

A study of "white spotted kidneys" in cattle

A study was performed at an abattoir in Australia, in an attempt to correlate focal chronic interstitial nephritis (FCIN) producing the so-called "white spotted kidney", with Leptospira spp. and other pathogens in cattle. Samples of kidneys, urine and blood were collected immediately after slaughter from 46 two-year-old heifers, and 72 cows and bulls with gross lesions consistent with FCIN. The same samples were also collected from nine heifers and 12 cows with no gross kidney lesions. Aqueous humour was also collected from the eye of 17 of the adult animals. The sera were processed by a microscopic agglutination test for leptospira antibodies, while all the other samples were cultured for Leptospira spp. and also processed for routine aerobic and anaerobic culture for other pathogens. Sub-samples from all the kidneys were fixed in 10% buffered formalin and processed histologically. Antibody titers of 1:400 or higher for Lepstospira borgpeterseni serovar hardjo were found in six adult animals with FCIN and in one adult animal with no gross kidney changes, while antibody titers of 1:400 to L. borgpeterseni serovar tarassovi were found in only one animal with FCIN. L. borgpeterseni serovar hardjo was isolated from the urine and kidney of one adult animal and from the urine of another adult animal, both with FCIN. No pathogens were isolated from any of the other samples. The histological lesions were consistent in most cases with FCIN. The results suggest that neither Leptospira spp. nor active infection by other bacteria are associated with the so-called "white spotted kidneys".