Prevalence of foot disorders in lactating Jersey cows raised in semi-confinement

Background and Aim:

To establish prevention strategies, recording the prevalence of foot injuries within a herd should be the starting point in determining the risk factors involved in digital diseases. This study aimed to assess the prevalence of claw disorders in lactating Jersey cows raised in a semi-confinement system.

Materials and Methods:

Five hundred and eighty-four digits were examined from 73 lactating Jersey cows. The lameness score system was used to assess each cow while walking and on standing position, and digital lesions were evaluated with the cows restrained in a hydraulic cattle chute.

Results:

The prevalence of digital lesions was 93.1%. Among the 68 affected cows, only 21 were lame. Of the 584 digits examined, 970 lesions were recorded, corresponding to 13.3% lesions per cow and 1.66% injuries per digit. Forty-eight cows (65.7%) had lesions in all digits, and 92.8% of digits had at least one lesion. Lesions in digits of fore limbs were more common (55.3%) (p<0.0001) than those of hind limbs (44.7%). Foot injuries in medial digits of the fore limbs were more prevalent (56.8%) (p<0.001) than in the lateral digits (43.2%). The lesions’ occurrence was similar in both medial and lateral digits of the hind limbs (p=0.8347). The primary diseases observed were heel horn erosion (53.8%), white line disease (19.3%), and double sole (12.4%), which together accounted for 92.4% and 84.9% of foot disorders diagnosed in the fore and hind limbs, respectively. Other digital diseases occurred less frequently.

Conclusion:

The prevalence of foot disorders in lactating Jersey cows raised in semi-confinement systems was high. This could be due to the lack of preventive trimming, infectious diseases, and nutritional problems.

Immunohistochemical Detection of Intralesional Antigens of Ovine Gammaherpesvirus-2 in Cattle with Sheep-associated Malignant Catarrhal Fever

Sheep-associated malignant catarrhal fever (SA-MCF) is a severe lymphoproliferative disease of ruminants caused by ovine gammaherpesvirus-2 (OvHV-2). Since the initial identification of SA-MCF there has been extensive research related to the pathogenesis of OvHV-2, based primarily on serological and molecular assays associated with typical histopathological findings. The monoclonal antibody (MAb-15A) binds to a common epitope in MCF viruses and is used frequently in serological investigations. However, the utilization of this antibody to detect antigens of OvHV-2 in tissues has not been examined. Accordingly, this study standardized an immunohistochemical assay using MAb-15A to identify antigens of OvHV-2 in tissues of cattle (n = 5) with SA-MCF. All animals developed acute neurological signs, without ocular and nasal manifestations, and had nucleic acids of OvHV-2 in brain tissue detected by polymerase chain reaction. The principal histopathological findings were lymphocytic nephritis (n = 5), widespread arterial proliferation and vasculitis (n = 5), lymphocytic portal hepatitis (n = 3), non-suppurative meningoencephalitis (n = 2) and atrophic enteritis with cryptal necrosis and dilation (n = 2). Intralesional intracytoplasmic antigens of OvHV-2 were identified within multiple epithelial cells of the kidneys of all animals, the intestines of animals with and without atrophic enteritis, and within epithelial cells of bile ducts in animals with lymphocytic hepatitis. Additionally, there was positive intracytoplasmic immunoreactivity within histiocytes and lymphocytes in several tissues. These findings suggest that the MAb-15A detects antigens of OvHV-2 within epithelial cells and leucocytes in several organs. Moreover, this assay would contribute significantly towards understanding of the pathogenesis of SA-MCF and may be used for retrospective studies. Additionally, angiopathy in SA-MCF may be a progressive lesion, which may terminate in luminal occlusion and probably occurs irrespectively of the eye and head form of MCF.