Mastitis is a common illness of dairy cattle and is very costly economically to the dairy farmer. Thus there is a need to develop broad-spectrum therapies that are effective while not leading to unacceptably long antibiotic withdrawal times. The effects of the CH4-inhibitors nitroethane (2 mg/ml), 2-nitro-1-propanol (2 mg/ml), lauric acid (5 mg/ml), the commercial product Lauricidin ® (5 mg/ml), and a finely-ground product of the Hawaiian marine algae, Chaetoceros (10 mg/ml), were compared in pure cultures of S. aureus. Lauricidin® exhibited the most bactericidal acidity against S. aureus. These results suggest potential for treatments with a non antibiotic compound could be effective against mastitis.

Mastitis is a common illness of dairy cattle and is very costly economically to the dairy farmer. Thus there is a need to develop broad-spectrum therapies that are effective while not leading to unacceptably long antibiotic withdrawal times. The effects of the CH4-inhibitors nitroethane (2 mg/ml), 2-nitro-1-propanol (2 mg/ml), lauric acid (5 mg/ml), the commercial product Lauricidin ® (5 mg/ml), and a finely-ground product of the Hawaiian marine algae, Chaetoceros (10 mg/ml), were compared in pure cultures of S. aureus. Lauricidin® exhibited the most bactericidal acidity against S. aureus. These results suggest potential for treatments with a non antibiotic compound could be effective against mastitis.

Twenty Holstein steers subclinically infected with coccidia were allotted to 2 groups of 10 steers each. One group received a diet containing 0.5 mg of decoquinate/kg of body weight. After 25 days on the diet, there was no difference between the groups in lymphocyte blastogenic responsiveness mitogens; however, there were differences in neutrophil function. Lymphocytes from steers of the decoquinate-fed group had decreased random migration under agarose, enhanced cytochrome C reduction, and enhanced iodination activity. Other measures of neutrophil function evaluated (chemotactic index, Staphylococcus aureus ingestion, and antibody-dependent and-independent cell-mediated cytotoxicity) were not affected. After 30 days of decoquinate feeding, half of the cattle in each group received 5 daily IM injections of dexamethasone (0.04 mg/kg of body weight). The dexamethasone-treated steers from the group that did not have decoquinate in the diet developed clinical coccidiosis, whereas the decoquinate-treated steers remained clinically normal. Lymphocyte and neutrophil function were again evaluated for a 3-day period beginning 4 days after dexamethasone treatment was halted. Neutrophils from the steers that developed clinical coccidiosis after dexamethasone administration had significantly (P less than 0.05) inhibited random migration under agarose, cytochrome C reduction, and iodination activity, but significantly (P less than 0.01) enhanced S aureus ingestion. The feeding of decoquinate prevented the inhibition of neutrophil cytochrome C reduciton and lessened the inhibition of neutrophil iodination in the dexamethasone-treated group. Dexamethasone treatment was associated with an inhibition of lymphocyte blastogenic responsiveness to phytohemagglutinin in principals as well as controls.