Evaluation of vitamin K3 feed additive for prevention of sweet clover disease

Sweet clover poisoning in cattle is caused by an anticoagulant (dicumarol) that is formed in moldy sweet clover hay. Previous experiments with vitamin K3 and vitamin K1 in therapy trials indicated that vitamin K1 was effective in reducing prothrombin times but vitamin K3 was not. As a possible alternative in the use of toxic sweet clover hays, vitamin K3 was evaluated to see if it would prevent hemorrhagic crises when fed to cattle consuming toxic sweet clover hay. Vitamin K3 levels of 0, 0.45, 4.5, 11, and 45 mg/kg body weight/day were fed to 173-235-kg steers consuming toxic (40-50 ppm dicumarol) sweet clover. The 45-mg K3/kg/day supplement was not palatable and had to be discontinued. The 0.45, 4.5, and 11-mg K3/kg/day supplements did not significantly reduce the prothrombin times as compared to the 0-mg K3/kg/day group.     

Radiographic diagnosis of hereditary chondrodysplasia in newborn lambs

Normal appearing Suffolk lambs affected with hereditary chondrodysplasia (HC) and normal appearing unaffected lambs were radiographed at birth, and at 2, 4, and 8 weeks of age. In affected lambs, lesions were seen consistently in the elbows, shoulders, sternum, and spine. Similar lesions were not identified in unaffected lambs. A malformed Corriedale lamb was radiographed to compare its lesions to those seen in HC. The Corriedale lamb had islands of ossification of the anconeal process similar to those identified in lambs with signs of HC at birth. The islands of ossification seen in the Corriedale lamb were fused by 2 months of age, whereas elbow lesions seen in lambs with HC increased in severity during the same period.     

Analysis of the costs of veterinary education and factors associated with financial stress among veterinary students in Australia

Objective

To investigate the course‐related and other costs involved in obtaining a veterinary education in Australia and how these costs are met. The study also aimed to identify sociodemographic and course‐related factors associated with increased financial stress.

Methods

Students from seven Australian veterinary schools were surveyed using an online questionnaire. A total of 443 students participated (response rate 17%). Responses to survey items relating to finances, employment and course‐related costs were compared with sociodemographic factors and prior research in the area of student financial stress.

Results

Respondents reported spending a median of A$300 per week on living costs and a median of A$2,000 per year on course‐related expenses. Over half of respondents received the majority of their income from their parents or Youth Allowance (56%). A similar proportion (55%) reported that they needed to work to meet basic living expenses. Circumstances and sociodemographic factors linked to perceived financial stress included requiring additional finances to meet unexpected costs during the course; sourcing additional finances from external loans; an expected tuition debt at graduation over A$40,000; being 22 years or older; working more than 12 hours per week; living costs above A$300 per week; and being female.

Conclusion

The costs involved in obtaining a veterinary education in Australia are high and over half of respondents are reliant on parental or Government income support. Respondents with certain sociodemographic profiles are more prone to financial stress. These findings may have implications for the psychological health, diversity and career plans of veterinary students in Australia.     

Selection, outbreeding depression, and the sex ratio of scale insects

The black pineleaf scale insect has haploid males and diploid females. Ratios of males to females late in development ranged from 0.005 to 0.320 among insect subpopulations that were infesting different host trees. Demes well adapted to an individual ponderosa pine had a higher proportion of males than did demes that were poorly adapted to the host. Ratios of males to females rose in successive annual samples as natural selection increased insect adaptation. Gene flow between demes on different host trees produced predictable changes in the sex ratio.     

Managing the evolution of insect resistance to transgenic plants

The evolution of resistance in pests such as the European corn borer will imperil transgenic maize varieties that express insecticidal crystal proteins of Bacillus thuringiensis. Patchworks of treated and untreated fields can delay the evolution of pesticide resistance, but the untreated refuge fields are likely to sustain heavy damage. A strategy that exploits corn borer preferences and movements can eliminate this problem. Computer simulation indicates that this approach can delay the evolution of resistance and reduce insect damage in the untreated fields of a patchwork planting regime.