Effects of Added Substrate on Production of Red Swamp Crawfish, Procambarus clarkii, in Earthen Ponds without Planted Forage

The effects of addition of substrate consisting of plastic mesh fencing to experimental earthen ponds were evaluated for the culture of the red swamp crawfish, Procambarus clarkii, without planted forage. Mean daily yield (kg/ha/d), number of crawfish harvested (number/ha/d), and mean individual harvest weight were compared for ponds with and without substrate during a 2‐yr period. The surface area of added substrate was equivalent to 50% of the bottom surface area of the pond. Mean daily yield in the ponds containing substrate, based on a comparison with that of the previous year, increased by 80.2% and was principally attributed to a 66.7% increase in the number of crawfish harvested. Comparative values for the ponds without substrate were ?13.1 and ?11.7%. For the second year, the treatment‐dependent response was consistent. Mean daily yield for the substrate ponds increased by 48.8% compared to 15.0% for the ponds lacking substrate. The primary benefit of the substrate appears to be provision of refuge and three‐dimensional distribution of crawfish in the pond, thereby reducing the incidence of cannibalism and increasing the total number of crawfish harvested per hectare per day. The benefit of the substrate in a commercial production setting must be weighed against its cost and longevity as well as the conditions of the particular management scenario into which it may be incorporated.     

Bekämpfung von Sturm-, Wind- und Spätfrostschäden

European Journal of Forest Research -     

Mycobacteriosis in a black-tailed deer (Odocoileus hemionus columbianus) caused by Mycobacterium kansasii.

An eviscerated hunter-harvested female black-tailed deer (Odocoileus hemionus columbianus) was submitted to the Washington Department of Fish and Wildlife. The deer was emaciated, devoid of adipose tissue, and the parietal surface of the thoracic cavity contained multiple granulomas. Acid-fast bacteria were detected histologically from the granulomas and were isolated and identified as Mycobacterium kansasii, a nontuberculous mycobacterium sporadically reported to cause tuberculosis-like disease in a variety of vertebrates. This was the first report of symptomatic disease caused by M. kansasii in free-ranging deer. This case indicates that atypical mycobacteria can cause tuberculosis-like disease in free-ranging deer and illustrates the importance of identifying causative agents of tuberculosis-like disease in wildlife.     

DNA育种对养猪业的贡献

猪育种专家和生产者可做的工作决不仅仅是给猪称重,而是从较大窝重中选择后备母猪和选择生长最快的猪或有价值的猪。分子图谱(DNA)分析对猪遗传育种专家如何选择目前商品猪群中遗传的差异具有划时代的影响。过去10年中,猪遗传育种专家第一次直接研究了猪的染色体图谱,包括自由遗传标记和已经知道的基因。就像交通地图一样,在这些图谱上,研究者可以分析和找到影响猪主要经济性状的染色体区域和主要的基因。这些研究已经以遗传检测(DNA)的形式产生了真正的成果,该检测对个体生产者和育种公司改善种群具有重要作用。在养猪行业中,可以采用大…     

Cooperating with industry to teach food-animal medicine

Cooperative programs with agribusiness offer opportunities for colleges of veterinary medicine to expand their instructional programs in agricultural practice. Agribusinesses associated with livestock agriculture recognize the importance of veterinary medicine in maintaining a vibrant and successful industry. Stewardship of corporate support involves close communication with advocates within the companies, providing them with documentation of the potential effects of corporate investments. This article describes the creation of the Michigan State University (MSU) Training Center for Dairy Professionals, a key aspect of which was the identification of innovative and productive areas of mutual interest and benefit. In addition to supporting the dairy industry by training veterinary students, the program offers specific benefits to investors, including the use of MSU facilities and direct participation in veterinary instruction.