Efficacy of multiple and single intramammary infusions of benzathine cloxacillin (500 mg/quarter) were compared for treatment of mastitis during the dry period. Treatments were three infusions, one each at 0, 7, and 14 d into the dry period; one infusion at drying off; and no infusions. Cows were grouped (30/treatment) based on previous mastitis history, mean monthly SCC, mature equivalent milk production, and pathogen detected pretreatment. Infected quarters/cow at parturition, posttreatment were 1.26, 1.6, and 2.35 for multiple, single, and no infusion groups, respectively. Milk production and somatic cell count posttreatment were not affected by treatment. Across all genera of microorganism, 75.5, 73.6, and 52.8% of infections were eliminated in the multiple, single, and no infusion groups, respectively. Primary effect of multiple infusions with cloxacillin in the dry period was to prevent new streptococcal infections. Sensitivity tests on staphylococcal isolates indicated that cloxacillin was still an effective dry cow treatment after 7 yr of use in the herd. Resistance to cloxacillin in approximately half the posttreatment staphylococcal isolates appeared to be nonenzyme (penicillinase) dependent. Multiple dry cow treatments with cloxacillin do not offer any advantage over a single treatment.

Manure from beef steers confined on concrete was blended with a basal ration at 20, 40, and 60% and ensiled at 25C. The moisture content of the rations increased with manure added. The rations with higher moisture developed a lower pH and higher lactic acid during the 10-day ensiling. Coliform bacteria were not detected in rations with 40% and 60% manure after 5 days ensiling and after 10 days in the 20% manure-blended ration. Coliform count of the basal ration (no manure) remained constant at about 104/g. When pH dropped to 4.4 to 4.7, coliforms died in all manure-blended rations. Salmonellae were isolated twice from 66 samples of the manure-blended rations and ration constituents (basal ration and manure) prior to ensiling. Salmonellae were not recovered from the salmonellae positive manure-blended rations after 3-days ensiling. The total bacterial count, numbers of acid-producing bacteria, and numbers of yeasts and molds decreased in the manure-blended rations after 10 days ensiling. Sporeform-ing bacteria survived but did not proliferate in the ensiled rations. The predominant acid-producing bacterium in the manure-blended rations prior to ensiling was Streptococcus faecalis. After 10 days ensiling Lactobacillus plantarum was the predominant type.

Cellulose digestibility of corn silage, ensiled with four percents (0, .05, .10, and .20% on a dry matter basis) of fungal cellulase, enzyme no. EC 3.2.1.4. of Trichoderma viride, was studied by the nylon bag technique with six rumen-fistulated cows. After 1 yr in the silo, cellulose content of the cellulase treated forages was lower than that of the untreated materials. Cellulase activity of the silage, at the time of feeding, as measured by “filter paper activity”, coincided closely with treatments. The pH of ensiled forage varied inversely with cellulase treatment, indicating increased fermentation of carbohydrates at higher enzyme, apparendy resulting from some breakdown of cellulose in the silo. Coefficients of cellulose digestibility for cows receiving a corn silage ration were 48 to 51% compared to only 12 to 24% for animals consuming sericea lespedeza hay.