The authors reported an outbreak of infection occurring in a small poultry laying farm without obvious symptoms of sick birds. The mortality rate within a few week-period of onset was up to 50%. Post mortem examinations were conducted and the lesions were described. With the aid of bacteriological confirmation including biochemical and pathogenicity test, the cause of the disease was found to be Pasteurella multocida. None of the birds died after one-week treatment and management.

The adverse effects of Monensin sodium and Troleandomycin in commercial broiler chickens in a commercial farm, confirmed by experimentation, were exhibited as sudden onset, leg weakness, prostration, unable to stand up and death. Morbidity rate was 30%, mortality rate was over 10%. Postmortem examination of these birds showed no significant lesions.

The primary objective of this study is to determine the extent of agricultural cooperatives' contribution to fertilizer diffusion at the farm level. A systematic interview of villagers together with the observation of village behavior and attitude in rural Chiangmai form the hard core data on which the findings of this empirical study rest. Chi-square tests of independent variables have been employed to determine the relationship of agricultural cooperative membership and fertilizer adoption. None of the results is statistically significant. This implies that agricultural cooperative fails to influence fertilizer adoption in the research area. This is consistent and thus reinforced by the field observation. The failure of the agricultural cooperative in introducing fertilizer to farmers is due not only to the inefficiency of the cooperative but also the unfavorable price ratio between fertilizer and agricultural product as well as the unreliable quality of fertilizer. The field data collection was financed by an ADC research grant. The report writing has been made possible by ISEAS of Singapore.

Effects of levamisole dilutions on HA of Newcastle Disease virus were studied in vitro and the findings are: 1. Treatment period 4 hours (at room temperature) - 1.1 When levamisole were mixed up to make final dilutions of 0.02 and 0.05% with NDV, no effect on HA was apparent; 1.2 When the final dilutions were 0.1, 0.25, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5 and 4.0%, the HA dropped significantly; 1.3 When the final dilution were 4.5 and 5.0% all HA activities of the NDV were destroyed. 2. At final dilution 0.02% levamisole did not affect the HA when the NDV were treated for 24 hours at room temperature. 3. HA activities of NDV was usually affected when NDV were treated longer than 4 hours when the final dilutions of levamisole were higher than 2.0%. Levamisole dilution should not exceed 0.1% when it is used as ND Vaccine diluent.

Six outbreaks of Aujeszky's disease in pigs have been confirmed by the Department of Pathology, Faculty of Veterinary Science, Chulalongkorn University since December, 1977. The clinically ill piglets were submitted and diagnosed by several laboratory methods. F.A. tests applied on brain impression smears and cryostat tonsil sections were rapid and gave an accurate results. Taking more time, histopathology of brains, tonsils and other organs of the infected pigs and the rabbit inoculation with the isolated virus were found reliable to support the F.A. tests. In this study, 21 out of 22 piglets from the 6 outbreaks of Aujeszky's Disease had non-suppurative encephalitis associated with Cowdry tape A intranuclear inclusion bodies in nerve and glial cells. Focal necrosis on livers, lungs, spleens, lymph nodes and tonsils were common. Rabbits developed intense pruritus at the site of injection at 2-4 days after inoculation of the virus. Clinically, the affected pigs, in all 6 outbreaks, exhibited nervous and respiratory signs and the pregnant swine had a high rate of abortions during the outbreaks.

Culture of the giant freshwater prawn in three different systems were comparatively studied. These culture systems are: 1) a large earthen pond; 2) nylon cages submerged in an irrigation canal; and 3) a longitudinal ditch located in an orchard. Each culture system was initially stocked with juvenile prawns at 5 prawns/m2. The prawns were fed with a compound diet at the same ratio for the experimental period of six months. The results showed a significant difference on growth among these three systems. The prawns reared in cages exhibited the poorest growth while those of the other two systems exhibited better and comparable growth. Nevertheless, the prawn reared in cages showed the best survival (52.5%). Survival of prawn reared in the earthen pond and the longitudinal ditch were 48.0% and 35.2%, respectively. The yield per rai (0.16 ha) per crop (six months) of these three systems were 210 kg, 138 kg, and 74 kg, respectively. The factors affecting growth, survival, and production of the prawn are discussed.

Fish feed, in general, contains protein content not less than 35%. At present, the use of the fish meal as a source of protein is facing problem since the price of fish meal has been increasing and often unavailable. Thus, there is a need to replace fish meal with another source of protein. Since the brewers' yeast contains 38-42% protein it might be possible to produce fish feed.