| bovine mastitis in ontario due to mycoplasma agalactiae subsp. bovis. | bovine mastitis caused by mycoplasma agalactiae subsp. bovis was first diagnosed in 16 of 55 cows in an ontario herd in feburary 1972. a total of 182 of 598 (30.4%) cows from 33 of 64 (51.5%) farms in widely separated areas of the province were culturally positive. herd incidence varied from 15 to 40% with one closed herd having an incidence of 61%. four herds were investigated culturally and serologically by the growth inhibition test for 15 months. in the acute phase the organism was present i ... | 1976 | 1000385 |
| the frequency, distribution and effects of antibodies, to seven putative respiratory pathogens, on respiratory disease and weight gain in feedlot calves in ontario. | during 1983-85, 279 calves requiring treatment for bovine respiratory disease and 290 comparison (control) animals from 15 different groups of feedlot calves were bled on arrival and again at 28 days postarrival. their sera were then analyzed for antibodies to seven putative respiratory pathogens. on arrival, the prevalences of indirect agglutination titers to pasteurella haemolytica, p. haemolytica cytotoxin, mycoplasma bovis and m. dispar were greater than 50%, the prevalence of titers to bovi ... | 1989 | 2766158 |
| diseases and pathogens associated with mortality in ontario beef feedlots. | this study determined the prevalence of diseases and pathogens associated with mortality or severe morbidity in 72 ontario beef feedlots in calves that died or were euthanized within 60 days after arrival. routine pathologic and microbiologic investigations, as well as immunohistochemical staining for detection of bovine viral diarrhea virus (bvdv) antigen, were performed on 99 calves that died or were euthanized within 60 days after arrival. major disease conditions identified included fibrinos ... | 2006 | 16566254 |