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J M Gillespie A R Schupp 《Veterinary Clinics of North America: Food Animal Practice》1998,14(3):373-386
The ratite industry remains in the market introduction stage of evolution; basic information on markets and production is limited. It is uncertain when, or perhaps whether, either the ostrich or emu industries will progress to the market growth stage. Until significant expansion occurs, ratite operations are likely to be faced with low or even nonexistant profits. It is the authors' observation that the ostrich industry is making slow but significant progress toward introducing products into potential growth markets. The fact that ostrich products were in demand prior to the ostrich being introduced into North America has helped the industry. The future of the emu industry appears to be much less certain. In the authors' opinion, in order for the emu industry to become profitable and grow, significant promotion of emu meat and immediate resolution of the value of the oil must be achieved. Meat sales alone will not carry emu production as a profitable commercial enterprise. Veterinarians can derive significant conclusions from this information. Currently, ratite production is composed of firms generating losses or minimal profits. South African producers are receiving approximately the same amount for a slaughter ostrich as North American producers. It is unlikely that North American ostrich prices will increase significantly. Prices of ostrich breeders of $2,000 to $4,000 per pair and $400 to $450 for slaughter birds are likely to remain the same for some time. Given that world demand has increased at a slower rate than supply, prices may decrease further. Breeder and slaughter birds will continue to require significant veterinary care; however, the producer will be forced to perform more farm treatments, given the negligible margins. Based on the differences in efficiency of existing operations, there are ample opportunities for veterinarians and extension services to assist producers. Vertical coordination in the ratite industry may evolve slowly in the future, especially in the arid regions of the country; however, economies of size in ratite slaughter are likely to remain uncaptured in the short run, limiting the rate at which vertical coordination evolves. If significant opportunities develop for veterinarians in vertically integrated ratite firms, the emphasis, as with other intensive livestock operations, will be preventative rather than therapeutic medicine, and will involve the integration of nutrition, management, genetics, and the control of disease. 相似文献
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S Sen S.M Shane D.T Scholl M.E Hugh-Jones J.M Gillespie 《Preventive veterinary medicine》1998,35(4):265-295
Velogenic viscerotropic Newcastle disease (vvNCD), which is endemic in Cambodia, can be prevented in theory by a combination of biosecurity and immunization of broiler flocks. The relative contribution of appropriate biosecurity and effective vaccination was quantified at the farm level, applying realistic projections for capital investment, fixed and variable production costs and losses following infection. Non-protected broiler flocks generate a loss when the probability of vvNCD infection exceeds 0.4. Applying both biosecurity and effective vaccination would sustain profitability up to a probability of exposure of 1.0. The benefit to cost ratios for alternative strategies were evaluated for a range of probabilities of exposure to vvNCD extending from 0.1 to 1.0. The benefit-to-cost ratio for biosecurity exceeded unity at a risk of exposure exceeding 0.1, and 0.2 for vaccination and the combination of vaccination and biosecurity respectively. A sensitivity analysis demonstrated that the efficiency of protection, feed cost, and financial consequences of infection markedly affected the projected benefit-to-cost ratios associated with alternative methods of prevention. 相似文献
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Blount BC Ozpinar A Alwis KU Caudill SP Gillespie JR 《Journal of agricultural and food chemistry》2008,56(22):10709-10715
Perchlorate is an inhibitor of iodide uptake that is found widely in the environment. Given the potential for perchlorate accumulation during egg formation and the widespread consumption of eggs, it is important to examine eggs as a source of exposure to perchlorate and other potential inhibitors of iodide uptake (nitrate and thiocyanate). This study was conducted to determine potential human exposure to perchlorate from eggs produced by chicken flocks consuming differing amounts of perchlorate. The mean concentrations of perchlorate (7.16 ( 1.99 microg/kg of dry weight), nitrate (2820 ( 2100 microg/kg of dry weight), thiocyanate (574 +/- 433 microg/kg of dry weight), and iodide (2980 ( 1490 microg/kg of dry weight) in eggs (n = 180) from 15 chicken houses on 3 U.S. farms were determined. Chickens secreted into eggs an average of 23% of the perchlorate ingested from feed and water. Perchlorate levels in eggs were positively correlated with perchlorate intake (p < 0.001). Increased intake of perchlorate, nitrate, and thiocyanate was associated with decreased iodide levels in eggs, possibly indicating a competitive transport mechanism, such as sodium-iodide symporter. It was estimated that egg consumption contributes minimal perchlorate (approximately 0.040 microg) compared to the average total intake of approximately 10.5 microg for U.S. adults. Additionally, it was found that egg consumption was not associated with increased perchlorate exposure in 2820 individuals from the National Health and Nutrition Examination Survey (p value for the difference of least-squares means, pDiff = 0.225). From these findings it was concluded that, although chickens secrete perchlorate in eggs, eggs do not appear to be a significant source of perchlorate exposure for adults in the United States. 相似文献