Tramped teats--clinical mastitis disease complex in tied cows. Environmental risk factors and interrelationships with other diseases.

The effects of stall length, manure system, type of bedding and calving disorders on incidence rates of tramped teats, udder injuries, and clinical mastitis in Swedish Red and White tied cows, as well as interrelationships between these 3 disorders were investigated. Data used consisted of 370 herds, for a total of 45,133 cow records. Cows in herds with liquid manure system were at higher risk of udder injuries and mastitis than in herds with solid system. Lower risk of both udder injuries and mastitis was found for cows in herds with short stall size (less than 180 cm) compared to herds with stalls of 205-219 cm length. It was suggested that other factors, such as slipperiness of the stall floor and presence and type of feeding barrier, must be considered when the effect of stall characteristics on tramped teats is investigated. In farms with solid manure system cut straw or sawdust bedding increased the risk of tramped teats and mastitis relative to uncut straw. Parity and calving disorders were important risk factors for udder health and their effect was greater in herds with liquid manure system. Tramped teats and udder injuries were the most serious risk factors for clinical mastitis.

Case-referent study of cystic ovaries as a risk indicator for twin calvings in dairy cows.

The association between cystic ovaries and twin births in dairy cows was analyzed in an epidemiologic study. The case-referent study design was chosen. The cases were all twin-bearing cows during the observation period. Two different groups of cows giving birth to single calves were used as controls. One group consisted of cows from the same herds as the twin-bearing cows; the second group consisted of cows randomly selected from the entire population. The frequency of cystic ovaries was significantly higher in control cows from herds with twin-bearing cows than in control cows randomly selected from the general population. This finding suggests an indirect association between the occurrence of cystic ovaries and the birth of twins. The direct association between cystic ovaries and birth of twins was evaluated by odds ratio. The magnitude of this measure varied according to breed and the control group used for calculation. A biological explanation for this finding could be that the frequency of intrauterine death and resorption of one twin fetus differs among breeds and cows with or without a history of cystic ovarian disease.

Removal risks in Swedish Friesian dairy cows according to parity, stage of lactation, and occurrence of clinical mastitis.

The removal risk of Swedish Friesian dairy cows was analysed. The risk of removal increased with parity, and first parity cows were removed earlier in lactation than cows of higher parities. A positive report of clinical mastitis increased the risk of removal, both in the month of developing mastitis and during subsequent part of lactation. The consequences of different removal pattern for epidemiologic analyses of observational studies are discussed.

Inhibition of the blastogenic response of peripheral blood mononuclear cells to mitogen and antigens by bovine pulmonary macrophages and their culture supernatants.

Bovine pulmonary macrophages were shown to inhibit blastogenic response of peripheral blood mononuclear cells to high and low level stimulation with phytohaemagglutinin P. The blastogenic response of cells from calves sensitised to Pasteurella haemolytica or BCG, when stimulated with the corresponding antigen, was also suppressed by the addition of autologous pulmonary macrophages. Twenty-four-hour-old macrophage culture medium was likewise inhibitory to the blastogenic response. Determination of the arginine content of culture medium before and after 24 and 48 hours' incubation with macrophages showed a progressive decrease in arginine content. Dilution of the arginine deficient medium 1:16 with fresh culture medium did not reverse the inhibition, thus making arginine deficiency unlikely to account for the inhibition.

Toxicity of Haemophilus pleuropneumoniae for porcine lung macrophages, peripheral blood monocytes, and testicular cells.

Strain CM5 of Haemophilus pleuropneumoniae was toxic for porcine lung macrophages in minimum doses of 10(6) colony-forming units per ml and for peripheral blood monocytes at 10(7) colony-forming units per ml. The organism was not toxic for porcine testicular cells in a concentration of 10(8) colony-forming units per ml. Filtered sterile culture supernatant diluted 10(0), 10(-1), and 10(-2) was toxic for porcine pulmonary lavage cells. In dilutions of 10(0) and 10(-1), culture supernatant was toxic for peripheral blood monocytes, and at 10(0) it was toxic for testicular cells. Toxicity associated with bacterial cells was sensitive to heating (60 degrees, 60 min), whereas that of the culture supernatant was heat stable (100 degrees C, 15 min). Swine convalescent serum neutralized supernatant toxicity in dilutions of greater than or equal to 1:320. The findings promote the understanding of the pathogenesis of pleuropneumonia in swine caused by H. pleuropneumoniae.

Lack of intracellular degradation of Mycobacterium paratuberculosis by bovine macrophages infected in vitro and in vivo: light microscopic and electron microscopic observations.

Blood-derived macrophages from clinically healthy cows and cows infected with Mycobacterium paratuberculosis were cultured in vitro and inoculated with heat-killed M paratuberculosis. Five weeks after infection, acid-fast bacteria continued to be demonstrated in the macrophages. Macrophage cultures also were infected with living M paratuberculosis and were examined by electron microscopy. Four weeks after infection, intact bacteria were found in all cultures. Electron microscopic examinations of intestinal macrophages from infected cows also demonstrated intracellular intact bacteria.

Immunological reactions caused by infection with Mycobacterium paratuberculosis. A review.

The natural resistance of cattle to infection with Mycobacterium paratuberculsis in relation to their immunological reactions is recorded. In vivo and in vitro manifestations of cell-mediated immunity during infection are reviewed, together with the antibody responses. It is suggested that three distinct immunological states may arise following exposure to infection.

Application of the direct leukocyte-migration agarose test in cattle from a Mycobacterium paratuberculosis-infected herd.

Using johnin as the specific antigen, the direct leukocyte-migration agarose test was applied to 10 cows from a Mycobacterium paratuberculosis-infected herd. Nine of the cows did not have signs of paratuberculosis; 1 cow was clinically affected. The cows were slaughtered and, on the basis of histopathologic and cultural examinations of the intestines, were classified as infected or noninfected. Six of the healthy cows from which the bacterium was not isolated and the clinically affected cow reacted with migration indices lower than those of 3 healthy animals that were found to harbor the bacterium. It is suggested that the long incubation period of paratuberculosis could to some extent be due to immunologic tolerance.

Adenosine 3',5'-monophosphate in plasma, urine, and native and isoproterenol-stimulated leukocytes of dogs.

Adenosine 3',5'-monophosphate (cAMP) was determined by means of a commercial kit in urine and plasma from 40 hospitalized dogs and in native and isoproternol-stimulated leukocytes from 30 of these animals. Mean urine and plasma concentrations were 6.1 micron and 14 nM, with 95% tolerance limits ("normal values") ranging from 0.0 to 12 micron and 0.21 to 27 nM, respectively. The plasma concentration was approximately half the value previously reported for experimental dogs. The median cAMP content in native leukocytes was 5.9 pmol/10(7) cells. The mean response to isoproterenol was 0.85 pmol/10(7) cells, much less than in human leukocytes. The response was statistically significant (P less than 0.01), but was so small that it is unlikely to be measurably affected in atopic dogs.

Application of the direct leukocyte-migration agarose test in cattle naturally infected with Mycobacterium paratuberculosis.

Four cows with persistent diarrhea and complement-fixing antibodies to johnin were examined, using the leukocyte-migration agarose test (LMAT) with johnin as the specific antigen. The diagnosis of paratuberculosis (Johne's disease) was microscopically verified at necropsy. As control animals, 3 healthy cows and 3 cows with disease other than paratuberculosis were examined, using LMAT. The migration indices in the group of cows with paratuberculosis were significantly lower (less than 0.001) than those in the group of control cows. Furthermore, the migration zones of the unstimulated peripheral blood leukocytes in the former group were significantly smaller (less than 0.001) than those of the control group.