[Efficacy of individual smoking cessation instructions for general smokers among clients of a health center].

Smoking cessation instruction for individuals using a standardized smoking cessation manual and a handout developed by the authors was studied in a controlled trial among employees who visited a health center for Industrial Safety and Health Law mandated annual health examinations. Smokers in the study group were given 5-10 minutes smoking cessation instruction mainly by public health nurses and nutritionists following the above-mentioned manual and using the handouts. Subjects in both groups were interviewed by telephone to assess changes in smoking habits one month after the first contact. Smoking clients who came on Friday (132) and on Monday (93) were assigned to study and control groups, respectively. One hundred and nineteen members (90.2%) of the study group and 88 (94.6%) of the control group were successfully followed until one month after the initial contact. Seven subjects in the study group were not smoking one month after the instruction, while no one gave up smoking in the control group (p less than 0.05). It was confirmed by telephone survey that 6 of the 7 subjects who were not smoking at one month were still maintaining abstinence from smoking one year after the instruction. Smokers who did not stop smoking reported a reduction in their smoking dose in the study group. Lighter smokers reacted more readily to instruction than did heavier smokers and the knowledge level of subjects was positively associated with the success rate.

Effect of sire mating patterns on future genetic merit and inbreeding in a closed beef cattle population.

Alternative breeding strategies were simulated based on the population structure of the Tajima strain of Japanese Black cattle. An analysis of the population structure revealed that some sires up to 20 years of age have been used in Tajima. In addition, 95% of newborn calves were the progeny of only 20 sires, and their mating frequencies were significantly skewed. The current average inbreeding coefficient and founder genome equivalents of the strain were estimated to be 0.199 and 2.25, respectively. Average inbreeding coefficient is expected to reach 0.394 within 27 years. Thus, different breeding strategies were assessed for their effect on the level of inbreeding and average genetic merit. We compared strategies that (1) halve the sire service period, (2) double the number of mating sires and (3) lower the skewed sire mating frequency and optimize the frequency for weighted genetic merit and diversity. Reducing the service period yielded a 7.0-12.0% reduction in the rate of inbreeding while maintaining almost the same genetic gain. Increasing the number of sires resulted in a 19.3-21.3% reduction in inbreeding with a corresponding 1.6-8.4% reduction in gain. The rates of inbreeding from the optimized strategies decreased as the weight on genetic diversity increased. However, a strategy that emphasized only genetic gain yielded lower gain than other strategies because the strategy allowed only one sire to mate, resulting in reduced genetic variance and low accuracy of genetic evaluation. In contrast, a strategy with no emphasis on genetic gain when determining mating frequency resulted in reductions of 16.0% and 63.2% in genetic gain and inbreeding, respectively. The strategies examined here are easily applicable and can be expected to reduce immediate loss of genetic diversity.

Genetic analysis of calf market weight and carcass traits in Japanese Black cattle.

Heritabilities of and genetic correlations between additive direct and maternal genetic effects for calf market weight, and additive direct genetic effects for carcass traits, were estimated for Japanese Black cattle by REML procedures under 2-trait animal models. Data were collected from calf and carcass markets in Hyogo and Tottori prefectures and analyzed separately by prefecture. Calf market weight was measured on 42,745 and 23,566 calves in Hyogo and Tottori, respectively. Only the fattening animals with calf market weight were extracted from the carcass database and used for estimation. The carcass traits analyzed were carcass weight, ribeye area, rib thickness, subcutaneous fat thickness, yield estimate, beef marbling score, and 4 meat characters (color, brightness, firmness, and texture). Direct and maternal heritabilities for calf market weight were estimated to be 0.22 and 0.07 in Hyogo, and 0.37 and 0.15 in Tottori, respectively. The estimates of heritabilities for carcass traits were moderate to high in both prefectures. The estimates of direct-maternal genetic correlations for calf market weight were positive (0.17) in Hyogo and negative (-0.63) in Tottori. The direct effect for calf market weight was positively correlated with the direct effect for carcass weight (0.87 and 0.56 in Hyogo and Tottori, respectively) but negatively correlated with the direct effect for beef marbling score (-0.10 in both prefectures). The estimates of genetic correlations between the maternal effect for calf market weight and the direct effects for carcass traits varied from -0.13 to 0.34 in Hyogo and from -0.14 to 0.15 in Tottori. Because direct and maternal genetic effects for early growth traits can be evaluated from calf market weight data in the production system of Japanese Black cattle, this information should be incorporated into selection and mating schemes of the breed.