Dietary preference of dairy cows grazing ryegrass and white clover.

The dietary preference of lactating dairy cows grazing perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) was studied. Twelve groups of 2 lactating, Holstein-Friesian dairy cows grazed 1.2-ha plots containing conterminal monocultures of clover and grass. Half of the groups grazed a plot containing 75% clover and 25% grass (by ground area), with the remaining groups grazing a plot containing 25% clover and 75% grass. The intake rates of clover were higher than those of grass, and intake rates were higher in the evening than in the morning. During daylight hours, clover formed 63.2% of the diet of the groups offered 25% clover, which was higher than the 25% offered but lower than preference for 100% clover. This indicated that cows showed a partial preference for clover, with an overall value (i.e., the mean of the 75% and 25% clover groups) of 73.8%. There was a diurnal pattern to preference, with a stronger preference for clover in the morning and with the preference for grass increasing during the day. The basis for partial preference remains unclear and warrants further research.

Genetic variation in two cultures of Bradyrhizobium japonicum 110 differing in their ability to impart drought tolerance to soybean.

The polymerase chain reaction with arbitrary primers (RAPD) discriminated between two separately maintained cultures of Bradyrhizobium japonicum USDA 110 differing in symbiotic performance under drought conditions. Since strain 110 is used in inoculum production, the use of RAPD to monitor inoculum cultures could help to preserve their genetic composition and prevent the loss of important symbiotic properties. The use of RAPD could also be extended to other B. japonicum strains currently used in inoculum production.

Attitudes toward drug use: trends and correlations with actual use.

Monitoring revealed a consistent relationship between attitude and use for those drugs which showed a definite trend in use, whether upward or downward. Increasing use, which applied to five of the eight groups of drugs surveyed, was associated with more permissive attitude to use and an increasing denial of danger. The reverse applied to decreasing use, found only in the case of the stimulants. On the other hand, in the case of drugs which showed no change in the rate of use, a change in attitudes could still occur. In the case of tobacco and narcotics, which showed no significant overall change in use during the 3 years of monitoring, the change in attitudes reflected the effects of intervention programs. The data are interpreted to indicate that health education had arrested an upward trend in use by discouraging the potential moderate user, but failed to influence the heavy user, whose numbers increased. Reflecting the associated change in attitudes, nonusers became increasingly inclined to prohibition, all groups increasingly recognized the dangers of use, and the heavy users showed less denial of danger and a more realistic self-estimation of use than was apparent for all other groups of drugs. The relative stability of narcotics use would seem to result from the containment exerted by vigorous law enforcement rather than from a favorable response of the community to education. Overall, the attitudes became increasingly permissive and inclined to denial of danger. The data suggest that the potentiality for an upward trend in use remains a constant danger.

Monitoring trends in drug use.

The pattern of drug use in a community can alter so rapidly that the conventional methods of survey do not adequately assess the dynamics of the situation. Monitoring may indicate changes in prevalence, attitudes, and a variety of other criteria in the course of time, and from this base allow assessment of intervention measures and the prediction of trends. Annual surveys of selected population groups with a self-administered questionnaire established the utility of this technique of monitoring, and revealed a progressive increase in the use of licit and illicit drugs, principally alcohol and marijuana. The only group of drugs to show a decrease in use were the stimulants.

Deviancy, delinquency and drug use.

A system for monitoring drug use was based on the data from annual surveys of two contrasting population groups, a general cross-section of young people and a cross-section of antisocial deviants. Correlation of deviancy and drug use established that drug use, both licit and illicit, was more extensive among those who suffered parental deprivation, whose parents were divorced or separated, who had psychiatric illness and particularly those who had committed antisocial acts. The degree of antisocial deviancy correlated with the extent of drug use.

The dynamics of trends in drug use in Australia.

Drug use tends to follow cycles. Monitoring may be used to establish the trends over time and to analyse their dynamics. An approach is described which establishes the stage of adoption or discontinuance of drug use in the community and a method for the prediction of future trends. Monitoring in New South Wales from 1971 to 1973 provided data which are analysed to show that alcohol was in the phase of majority adoption and tobacco had reached a plateau, but with the worrying anomaly that heavy use among young people continued to rise. Sedatives and analgesics had also reached a plateau stage of use. The data on marijuana are subject to more than one interpretation, but in any case point to a continuing rapid increase in use; predictions are made about future trends. Hallucinogens seemed to be in the phase of late adoption and stimulants to have entered a phase that is of particular interest, discontinuance. Narcotics seemed to be in the phase of late majority adoption.

Isolation of Salmonella enteritidis serotype Agona from eutrophic regions of a freshwater lake.

Salmonella enteritidis serotype Agona, which is associated with animal feeds containing fish meal, was isolated consistently from waters influenced by sewage containing poultry processing wastes.