Occurrence of cutaneous infections of Myxobolus episquamalis (Myxozoa: Myxobolidae) in sea mullet, Mugil cephalus L, in Australia

Objective To report the occurrence of Myxobolus episquamalis in sea mullet, Mugil cephalus L , caught in estuaries in eastern and western Australia.
Design A prospective study of commercial catches of mullet in the Clarence River of NSW and individual cases from other areas.
Results The organism caused pale, white to pink, raised lesions on the scales and fins of sea mullet. Occurrence of infection was highest in spring and in a marine (down-river) environment compared to a brackish environment. Up to 6% of fish were affected in commercial catches.
Conclusion The infection is widespread in Australian mullet, but rarely causes significant economic loss.     

Dairy-heifer management in the Netherlands

The objective of this study was to describe the Dutch rearing performance of dairy heifers by the evaluation of performance indices at weaning, breeding and calving. The second objective was to determine the extent to which dairy farmers use pre-set rearing targets and data monitoring for the evaluation of their rearing results. A questionnaire was sent to 3000 randomly chosen dairy cattle farmers to survey their heifer-rearing practices. Almost a third of the farmers (n=959) completed and returned the questionnaire. Of the farms responding, 29% realised an age at first calving of < or =24 months, 51% from 25 to 27 months, and 20% of > or =27 months. The farmers indicated that the average body weight after calving was within the range 525-550 kg. Average wither height class was 141-145 cm. Most farmers estimated the body-condition score of their heifers at calving to be 3-3.5. In 29% of the cases, weaning occurred at an age of < or =8 weeks, 35% at 9-10 weeks of age and 36% at > or =11 weeks of age. Most farmers (81%) commenced breeding at an age of > or =15 months.Intermediate evaluation of the rearing policy by means of performance goals and measurements was limited, and many of the reported performance indices on age and body weight were outside the range of the recommended target values. These results indicated that the common Dutch heifer-rearing management system could be improved considerably.     

Eliciting the relative importance of risk factors concerning contagious animal diseases using conjoint analysis: a preliminary survey report

Conjoint analysis is a technique well known in marketing research to elicit consumer preferences and opinions. This paper describes the results of an experiment which explores the potential application of conjoint analysis in the field of veterinary epidemiology and economics. In this experiment, the method of conjoint analysis was used to elicit the opinion of experts about the relative importance of risk factors concerning contagious animal diseases. Diseases studied were: African Swine Fever (ASF), Classical Swine Fever (CSF), Foot-and-Mouth Disease (FMD), Swine Vesicular Disease (SVD), Newcastle Disease (NCD) and Avian Influenza (AI). Risk factors included were import of livestock, import of animal products, feeding of swill, tourists, returning livestock trucks and air. The conjoint analysis technique was used to draw up a questionnaire which was handed out during the 7th ISVEE held at Nairobi, Kenya, from 15 to 19 August 1994. According to the experts approached, the factors ‘import of livestock’ and ‘import of animal products’ were the major sources of risk for all diseases. For ASF, CSF and FMD, the risk factor ‘swill feeding’ ranked third. For FMD and the two poultry diseases NCD and AI, only the risk factor ‘air’ was important. Overall conclusion was that conjoint analysis could be a useful method for eliciting the opinion of experts about risk factors concerning contagious animal diseases. In further research, special attention should be given to the selection of experts and the presentation of the conjoint questions.     

Distribution of lesions in ovine salmonellosis

SUMMARY Four forms of salmonellosis were recognised in feedlots and during transport by sea: septicaemic, and acute, subacute and chronic enteric. The severity and distribution of lesions in the enteric forms varied according to the progression of the pathological process. The acute disease involved the abomasum and small intestine whereas the subacute disease centred on the lower small intestine and upper large intestine. Chronic disease involved considerable mucosal repair in the ileum, caecum and proximal colon. Septicaemic salmoneiiosis was often accompanied by acute enteritis and occasionally by cholecystitis. S typhimurium was the most frequently encountered serotype.     

抗药性对球虫病流行病学的影响

在艾美耳球虫感染的群体动力学、影响球虫病流行病学的因素和抗药性可导致家禽业经济损失的环境条件等方面,人们的知识仍显得不足(HD Chapman,1997). 人们对抗药球虫怀有巨大恐惧感已有很多年了,这主要是因为养禽业记得二十世纪六十年代后期抗吡啶酮或抗喹诺酮柔嫩艾美耳球虫病的灾难性爆发.