Veterinary Pathology

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Browsing Veterinary Pathology by Author "Dr. Demissie, Tilaye"

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    Experimental Study on Sheep Infested With Bovicola Ovis and Melophagus Ovinus of Pathological Changes, Processed Skin Defect and Effect of Treatment in Improving Skin Quality
    (Addis Ababauniversity, 2015-10) Kebebew, Getachew; Dr. Demissie, Tilaye
    Experimental study was conducted from January, 2015 to August, 2015 on sheep experimentally infested by B .ovis and M. ovinus with the objective of identifying specific pathological changes they induce, the type of defect at pickle and their effect on skin quality and effect of treatment on resumption of skin to normal state. For this purpose, thirty indigenous sheep of Arsi origin approximately 18 months age were bought from market. They were treated against infection and parasites and kept for a month to stabilize them before the commencement of the experiment. The sheep were then grouped in to five groups each with six individual sheep as non-infested control, B .ovis infested untreated, B .ovis infested treated, M. ovinus infested untreated and M. ovinus infested treated. B .ovis and M. ovinus were manually collected from donor sheep; identified, counted and then infested at 500 B .ovis and 50 M. ovinus per sheep to the respective treatment groups. All groups were managed under similar condition and followed for 95 days and Sheep within the infested treated groups were treated with diazinon and followed for additional 30 days. The total WBC count was increased in B .ovis and M. ovinus infested groups compared to non-infested control group. However, the statistically significant was only for groups infested by M. ovinus (P< 0.05). In all infested groups the differential leukocyte count was increased; nevertheless, the significant difference was only for eosinophil (P <0.05). The common gross lesions noticed were skin discoloration with excreta, crust formation, macules and erythema for M. ovinus and B .ovis with slight difference in intensity of lesion. Microscopically, hyperkeratosis and acanthosis were more severe in groups infested by M. ovinus than B .ovis. The density of inflammatory cells infiltrating dermis was severely intensive in groups infested by M. ovinus than B .ovis. In groups that were treated, the gross pathological lesions except skin discoloration were totally disappeared within 30 days; nonetheless, the microscopic lesions persisted with a decrease in number of inflammatory cells specifically that of eosinophils. At pickle stage M. ovinus was characterized by large elevated cockles and B .ovis by extensive but small cockles. All processed skins from B.ovis and M. ovinus infested groups degraded and lied toward the stages of moderate x grades (5 or 6) and less which is very poor. In treated group 50% of the processed skins from B .ovis were improved in quality and were lied to grades 1 to 4 (very good to good) but only 33% of skin from M. ovinus were improved and lied to 1 to 4 grades. It could be concluded that infestation by B .ovis and M. ovinus cause severe to mild gross pathological lesions however severe microscopic lesions to sheep skin and reduced the quality of processed skin from top grades to low grade. Definitely treatment improves skin quality but not in all affected skin, and varies between B .ovis and M. ovinus. Keywords: B.ovis, Cockle, Ethiopia, Experiment, Lesion, M. ovinus, Sheep, Skin
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    Morphometrical, Pathological and Bacteriological Study of Mammary Gland of Cows With Subclinical and Clinical Mastitis in Selected Farms and Abattoirs in Central Ethiopia
    (Addis Ababauniversity, 2016-06) Meaza, Mandefrot; Dr. Demissie, Tilaye
    The cross sectional study was conducted from November 2015 to May 2016 in Bishoftu, Addis Ababa and Adama areas to evaluate cow’s udder morphometrical changes in relation to mastitis, mammary gland lesion characterization and isolation and characterization of aerobic bacteria from lesions. A total of 252 dairy cow from selected dairy farms in Bishofu and 72 udders from Addis Ababa and Adama municipality abattoirs were included in the study. The study revealed that the overall prevalence of mastitis was found to be 44.44% with clinical and sub-clinical mastitis accounting 16.11% and 36.67%, respectively. Morphometrically, cows with longer and thicker teats, greater distance between hind teats, Longer glandular longitudinal length and shorter teat end to floor distance had higher frequency of subclinical mastitis and the difference was statistically significant (P<0.05). However, udder and teat end shape had no significant association (P>0.05) with subclinical mastitis. Distance between hind teats and front udder height had direct statistically (p<0.05) association with somatic cell count. Out of 217 quarter milk samples cultured, 147 (67.74%) were positive for single colony, 46 (21.2%) for mixed bacterial growth and 24 (11.06%) were negative for bacterial growth. Predominant aerobic bacteria isolated were Coagulase Negative Staphylococci 66 (34.2%) followed by S. aureus 63 (32.8%) and E.coli 40 (20.7%). On the other hand, from culture result of 53 mammary gland tissue samples collected from abattoirs, the major isolated bacteria were E. Coli (35cases), streptococci (32 cases), S. aureus (23 cases), Coagulase Negative Staphylococci (14 cases),, and S. hyicus (11 cases). Tissue sections from abattoir showed glandular epithelial degeneration and necrosis, atrophy of alveoli and the glands, intestinal fibrosis, acute to sub-acute suppurative inflammation with neutrophil infiltration and chronic inflammation with mononuclear cell infiltration. Serum alkaline phosphatase analysis did not show significant difference between mastitic and non mastitic cows. In conclusion, mastitis was one of diseases of dairy cows in the study areas which could affect dairy production. Some udder traits could be risk factors to mastitis and chronic mammary lesions characterized might severely decreased milk production and could be reason for culling of dairy cows. Therefore udder traits might be part of dairy cattle selection and improvement programs with detailed further study on the subject in the country. . Keywords: Alkaline phosphatase, Bacterial isolation, Cow, Ethiopia, Histopathology, Mastitis, Somatic cell count, and Udder morphometry