Yasmin JibrilFekadu RegassaAkafete TekluMandefro Dargie2026-08-042026-08-042010-06https://etd.aau.edu.et/handle/123456789/8765The study was conducted with an objective of determining prevalence of mastitis in local zebu and cross breed lactating cows and assessing efficacy of seven phytopreparatons on commonly isolated pathogens of bovine mastitis. The study was based on 369 lactating cows with in small-scale extensive and semi-intensive husbandry practices in two selected highland and midland areas of Amhara region and in a large-scale intensive farm in Algae ATVET College. During sampling, each quarter was inspected for clinical case of mastitis and quarter milk from each cow was tested with CMT for sub-clinical mastitis. Plants were collected from their natural habitat, prepared, extracted and impregnated for efficacy test on (n= 12) isolates of Staphylococcus aureus and Streptococcus agalactia. With combined clinical inspection and CMT test, an overall prevalence of mastitis was 50.7% (16.0% clinical and 34.7% sub clinical) are cow base and 39.8% (6.3% clinical and 33.5% sub-clinical) at quarter level. A binary logistic regression analysis showed statistical associations of intensive farms (OR= 10.727, p= 0.000) with the disease than extensive husbandry practices. Cows at third and above lactation were statistically associated (OR= 5.418, P = 0.000) with mastitis than cows at first lactation. From seven plants tested for efficacy Bereza, Commicarpus pediculosus, Cyphostemum adenocaule and Xanthium stramarium showed visible zone of inhibitions. There was a significant difference' observed within mean zone of inhibition of plant types. Mean zone of inhibition from 20% Commicarpus pediculosus (29.00mm) was found statistically higher than (P<O.OI) mean from 20% Bereza (19.83mm). (P<O.Olmm) mean from 20% Cyphostemum (26.17mm) mean zone of inhibition from 20% Commicarpus pediculosis was also found statistically higher (P<O.OOI) than mean from penicillin G resistant isolates (19.13nml) and (P<O.OOI) than mean from oxytetracycline resistant isolates (11.25mm), 66.7% and 33 .3% of the isolates of Staphylococcus aureus were resistant to penicillin in G and oxytetracycline, respectively. The higher prevalence of mastitis and drug resistance development of isolates results economic loss to increase in a farm with a subsequent effect at national level. To combat the loss an effective control program needs to b e implemented. Finding alternatives for drug resistance are of the lections taken for the control program. in-vitro experiment result of plant efficacy in this study will be used as an input to solve the problem. Key words: Breed/ C:ow/Orug resistance/Economic loss/Efficacy/Ex traction/ Impregnation/ Plants/ Prevalence/ Mastitis/ MeanenBreed/ C:ow/Orug resistance/Economic loss/Efficacy/Ex traction/ Impregnation/ Plants/ Prevalence/ Mastitis/ MeanThesis