Resistance of gram-negative bacteria to gentamicin has become an increasingly common problem among clinical isolates from human beings. Susceptibility of isolates from horses to gentamicin and amikacin was evaluated for the period from July, 1983 to June, 1985. All isolates of Escherichia coli, and species of Enterobacter, Klebsiella, Proteus, and Pseudomonas examined were susceptible to amikacin, except 2 of the 46 Pseudomonas isolates. In contrast, 13 to 50% of isolates were resistant to gentamicin. Escherichia coli, and Klebsiella, Proteus, and Enterobacter species isolates were highly significantly more susceptible to amikacin (P less than 0.01) than to gentamicin. Pseudomonas spp (P = 0.13) were not significantly different in susceptibility to the 2 drugs. There was significant variation among genera in their susceptibility to gentamicin (P = 0.002), primarily because of the frequency of resistance in isolates of Klebsiella spp and Proteus spp, compared with the other 3 organisms (E coli, Enterobacter spp, and Pseudomonas spp). There was no significant difference of susceptibility to amikacin among the genera studied (P = 0.06).

Observations were completed over an 18-year period (1966 through 1983) in Thoroughbred mares (15/year) and yearlings (11 to 24/year) on a farm where benzimidazole-resistant small strongyles had emerged previously (1962 to 1965). This farm was operated as a closed, nonboarding type, which included a racing stable for its home-bred foals. At 2-week intervals, counts of worm eggs per gram of feces (EPG) and larvae per gram of feces were done to monitor strongyle infections and efficacies of bimonthly (every 8 weeks) antiparasitic treatments that were administered by stomach tube or were fed (dichlorvos pellets) to 1 group of yearlings during a 7-year period (1970 through 1976). The study included several drugs or mixtures, including thiabendazole (TBZ), phenothiazine (PTZ) + piperazine (PPZ)-carbon disulfide (CS2) complex, PTZ + PPZ + trichlorfon (TCF), dichlorvos, and pyrantel pamoate. These were used selectively in treated subgroups (usually 3/year) of mares and yearlings. The horses in drug treatment subgroups grazed together on common pastures; thus, efficacy comparisons between drugs were limited or nullified. However, annual mean EPG and larvae per gram of feces counts of mares and yearlings tended to increase over time, and for the yearlings treated with TBZ + PPZ and PTZ + PPZ-CS2, the buildup of these mean counts was statistically significant (P less than 0.05 for regression coefficients). These trends of annual mean counts to increase were a general index of loss of anthelmintic activity of the 3 drug mixtures containing PPZ (TBZ + PPZ, PTZ + PPZ-CS2, and PTZ + PPZ TCF); however, trends were indicated more definitively by 2 other indices: (1) loss of effectiveness in reduction of EPG counts 2 weeks after treatment and (2) decrease in performance for complete clearance of strongyle eggs (EPG, 0) 2 weeks after treatment. Loss of effectiveness over time was statistically significant (P less than 0.001) for the mares only when data was pooled for all 3 treatments (TBZ + PPZ, PTZ + PPZ-CS2, and PTZ + PPZ + TCF); however, the decreasing effectiveness was statistically significant (P less than 0.05) for TBZ + PPZ and PTZ + PPZ-CS2 treatment of yearlings. Statistically, clearance performance in mareswas significant for treatments with TBZ + PPZ (P less than 0.003) and PTZ + PPZ + TCF (P less than 0.005) and approached significance with PTZ + PPZ-CS2 (P greater than 0.06). Clearance performances in yearlings were highly significant (P less than 0.0003) for treatments with TBZ + PPZ and PTZ + PPZ-CS2. These analyses of data indicate that the intense and prolonged (greater than or equal to 18 years) use of PPZ as a common component in several of the drug mixtures had resulted in the selection of a segment of small strongyles resistant to PPZ. Multiple resistance of this population of small strongyles includes several drugs: PTZ, the benzimidazoles (except oxibendazole and albendazole), possibly pyrantel, and PPZ. Side effects of drug treatments were not apparent during the prolonged period of this study.

Four types of products made from Neem namely, neem leaf decoction, neem capsule, neem fresh juice and neem extract were given to 4 groups of goat for a period of 10 weeks to evaluate the effectiveness of these products in controlling natural gastrointestinal helminth infection. During the course of the study, faecal egg counts, Packed Cell Volume and FAMACHA readings were
monitored weekly. Results of feeding these products were variable when compared to untreated control animals, however, a 40-60% worm control was observed. Further testing is required to fine tune these
products for use in the field especially where anthelmintic resistance deems drugs to be ineffective.

Evaluation of safety and efficiency of application of immunostimulative drug Izambenum (C14H15IN2O) for stimulation of natural resistance (autarcesis) and immunologic responsiveness of chickens of laying breeds was realized in the conditions of the Republic of Belarus. Clinical and experimental investigation of Izambenum influence on poultry for the increasing of their resistance, activation of immunological response to vaccination against Newcastle disease, stimulation of their growth and development was realized. Research results showed that Izambenum influenced on level of morphological indexes of chicken blood: number of erythrocytes increased on 24%, hemoglobin - on 17%. Total protein in blood serum increased in all test period and number of lymphocytes increased and differential was 90-100%. Izambenum increased strains of post vaccination immunity to Newcastle disease. Bacterial growth-inhibitory activity decreased on the 27the day of life and increased at the same positions on the 34-41 days. Phagocyte activity of pseudoeosinophils increased in all test groups. Research results showed that Izambenum rendered growth and immunity stimulation action and increased their viability. Its immunostimulative action was conditioned by strengthening of cellular and to lower extent humoral immunity factors. Application of the preparation in period of Newcastle disease vaccination promoted the formation of long-lived immunity