Strategies for two-stage sampling designs for estimating herd-level prevalence     

Wagner B  Salman MD 《Preventive veterinary medicine》2004,66(1-4):1-17

We propose a herd-level sample-size formula based on a common adjustment for prevalence estimates when diagnostic tests are imperfect. The formula depends on estimates of herd-level sensitivity and specificity. With Monte Carlo simulations, we explored the effects of different intracluster correlations on herd-level sensitivity and specificity. At low prevalence (e.g. 1% of animals infected), herd-level sensitivity increased with increasing intracluster correlation and many herds were classified as positive based only on false-positive test results. Herd-level sensitivity was less affected at higher prevalence (e.g. 20% of animals infected). A real-life example was developed for estimating ovine progressive pneumonia prevalence in sheep. The approach allows researchers to balance the number of herds and the total number of animals sampled by manipulating herd-level test characteristics (such as the number of animals sampled within a herd).  相似文献   

Controlling emerging diseases in the 21st century     

Salman MD 《Preventive veterinary medicine》2004,62(3):177-184

The presentation addressed the following points: the role of veterinary epidemiology in emerging and global disease outbreaks; the contribution of veterinary epidemiology discipline to understanding and prevention of infections and other emerging animal disease, and the challenges for the discipline of veterinary epidemiology in the near future. The emerging and re-emerging infections animal diseases have contributed to expand the outlook of veterinary epidemiology. Methods and approaches in this discipline have been modified to satisfy the needs of society and of the scientific community. Mistakes and "bad turns" were made and should be avoided in the future. Veterinary epidemiology is alive and growing.  相似文献   

Use of epidemiologic risk modeling to evaluate control of foot-and-mouth disease in southern Thailand     

Wongsathapornchai K  Salman MD  Edwards JR  Morley PS  Keefe TJ  Van Campen H  Weber S  Premashthira S 《American journal of veterinary research》2008,69(2):240-251

OBJECTIVE: To assess the impacts of the introduction of foot-and-mouth disease (FMD) and various FMD control programs in southern Thailand. ANIMALS: A native population of 562,910 cattle and 33,088 buffalo as well as 89,294 animals legally transported into southern Thailand. PROCEDURES: A quantitative risk assessment was used to ascertain the probability of FMD introduction, and an intrinsic dynamic model was used to assess impacts. Value for the transmission rate (beta) was estimated. Five scenarios created to assess the impacts of nonstructural protein (NSP) testing, mass vaccination, and culling were examined. Impacts were assessed through an examination of the estimated annual cumulative incidence (ACI) of FMD. The ACIs of various scenarios were compared by use of the Tukey Studentized range technique. RESULTS: beta was estimated at 0.115. Approximately 35,000 cases of FMD would be expected from the baseline situation. A 30% reduction of ACI was detected with the introduction of NSP antibody testing. Prophylactic vaccination resulted in an 85% reduction of ACI. Concurrent use of NSP antibody testing and vaccination reduced the ACI by 96%, and the addition of an eradication policy resulted in a slightly greater decrease in the ACI (98%). CONCLUSIONS AND CLINICAL RELEVANCE: The study used epidemiologic models to investigate FMD control interventions. Results suggested that vaccination has more impact than the use of NSP testing. Use of the NSP test reduced ACI during peak seasons, whereas vaccination diminished the underlying incidence. The best mitigation plan was an integrated and strategic use of multiple control techniques.  相似文献   

Assessment of a germplasm bank for the autochthonous cattle breed Asturiana de la Montaña: Extender (Biociphos vs. BIOXCell) affected sperm quality but not field fertility     

Carolina Tamargo  Carlos O. Hidalgo  Jose Nstor Caamao  Amer Salman  Carmen Fueyo  Cristina Arija  ngel Fernndez  María J. Merino  Felipe Martínez‐Pastor 《Reproduction in domestic animals》2019,54(Z4):90-93

Semen banking is critical to preserving rare and autochthonous breeds. However, protocols can change with time, leaving heterogeneous semen batches. The objective of this study was to assess differences in sperm quality and field fertility. We report differences between batches frozen with the Biociphos and BIOXCell extenders in the Asturiana de la Montaña cryobank (autochthonous and endangered breed, Northern Spain). Doses from 48 bulls were analysed by CASA and flow cytometry. The 85‐days non‐return rates from AI records were used to assess the fertility of 23,853 AI. BIOXCell showed higher quality post‐thawing. Differences increased after a 5‐hr incubation at 37°C, and Biociphos yielded doses with lower resilience. Field fertility did not differ between extenders (Biociphos: 57.4% ± 1.2; BIOXCell: 56.6% ± 3.0), possibly because of AI protocols compensating for differences in quality. However, this needs to be confirmed by controlled intervention studies. In conclusion, batches frozen with Biociphos may require specific strategies for compensating for the lower sperm quality. Regular surveys and evaluation of cryobank procedures may be useful to characterizing stored batches and defining strategies to guaranteeing success in their future use.  相似文献   

Level of dietary energy and 2,4-thiazolidinedione alter molecular and systemic biomarkers of inflammation and liver function in Holstein cows     

Afshin Hosseini  Mustafa Salman  Zheng Zhou  James K.Drackley  Erminio Trevisi  Juan J.Loor 《畜牧与生物技术杂志(英文版)》2018,(1)

Background: The objective of the study was to evaluate the effect of overfeeding a moderate energy diet and a2,4-thiazolidinedione(TZD) injection on blood and hepatic tissue biomarkers of lipid metabolism, oxidative stress,and inflammation as it relates to insulin sensitivity.Results: Fourteen dry non-pregnant cows were fed a control(CON) diet to meet 100% of NRC requirements for3 wk, after which half of the cows were assigned to a moderate-energy diet(OVE) and half of the cows continued on CON for 6 wk. All cows received an intravenous injection of 4 mg TZD/kg of body weight(BW) daily from 2 wk after initiation of dietary treatments and for 2 additional week. Compared with CON cows and before TZD treatment, the OVE cows had lower concentration of total protein, urea and albumin over time. The concentration of cholesterol and tocopherol was greater after 2 wk of TZD regardless of diet. Before and after TZD, the OVE cows had greater concentrations of AST/GOT, while concentrations of paraoxonase, total protein, globulin, myeloperoxidase, and haptoglobin were lower compared with CON cows. Regardless of diet, TZD administration increased the concentration of ceruloplasmin, ROMt, cholesterol, tocopherol, total protein, globulin, myeloperoxidase and beta-carotene. In contrast,the concentration of haptoglobin decreased at the end of TZD injection regardless of diet. Prior to TZD injection, the mR NA expression of PC, ANGPTL4, FGF21, INSR, ACOX1, and PPARD in liver of OVE cows was lower compared with CON cows. In contrast, the expression of HMGCS2 was greater in OVE compared with CON cows. After 1 wk of TZD administration the expression of IRS1 decreased regardless of diet; whereas, expression of INSR increased after 2 wk of TZD injection. Cows fed OVE had lower overal expression of TNF, INSR, PC, ACOX1, FGF21, and PPARD but greater HMGCS2 expression. These differences were most evident before and after 1 wk of TZD injection, and by 2 wk of TZD differences in expression for most genes disappeared.Conclusions: Based on molecular and blood data, administration of TZD enhanced some aspects of insulin sensitivity while causing contradictory results in terms of inflammation and oxidative stress. The bovine liver is TZD-responsive and level of dietary energy can modify the effects of TZD. Because insulin sensitizers have been proposed as useful tools to manage dairy cows during the transition period, further studies are required to investigate the potential hepatotoxicity effect of TZD(or similar compounds) in dairy cattle.  相似文献   

Pot study on wheat growth in saline and waterlogged compacted soil: II. Root growth and leaf ionic relations     

Muhammad Saqib  Javaid Akhtar  Riaz Hussain Qureshi 《Soil & Tillage Research》2004,77(2):179-187

Soil compaction affects plant growth by causing increased resistance to root penetration and a decreased uptake of water and ions. A pot experiment was conducted to study the effect of soil compaction in conjunction with the soil salinity and waterlogging on root growth and leaf ionic composition of two wheat genotypes (Aqaab and MH-97). Compaction was achieved at a 10% soil moisture content by dropping 5 kg weight, controlled by a tripod stand for 20 times from 0.6 m height on a wooden block placed inside the soil-filled pots. Soil bulk density of non-compact and compact treatments was measured as 1.21 and 1.65 Mg m⁻³, respectively. The desired salinity level (15 dS m⁻¹) was developed by mixing required amount of NaCl in the soil before filling the pots. Waterlogging was developed by flooding the pots for 21 days both at tillering and booting stages. Compaction significantly reduced the root length density (RLD) of both the wheat genotypes while the combined effect of compaction×salinity was more drastic on root length density than compaction alone. Waterlogging however, did not decrease the root length density, rather it mitigated the effect of compaction. Compaction decreased the concentration of K⁺ and K⁺:Na⁺ ratio in leaves. Salinity also decreased the concentration of K⁺ and K⁺:Na⁺ ratio, but increased the concentrations of Na⁺ and Cl⁻ in the crop leaves. Salinity and compaction interacted to cause a greater reduction in K⁺ concentration and the K⁺:Na⁺ ratio, while there was lesser increase in the concentrations of Na⁺ and Cl⁻ compared with salinity alone. Waterlogging also decreased the concentration of K⁺ and K⁺:Na⁺ ratio in leaves. It intensified the effect of salinity but decreased the effect of compaction on leaf ionic composition. Therefore, the effect of compaction on root growth and ion uptake is more severe under salt-affected soil conditions than under normal soil conditions while occasional waterlogging of a compact soil for a few days makes the soil conditions favorable for root growth both under non-saline as well as saline soil conditions. Also, the performance of a genotype in stressed environment is related to maintenance of higher root length density, leaf K⁺ concentration and K⁺:Na⁺ ratio and lower leaf Na⁺ and Cl⁻ concentrations.  相似文献   

Trace elements and prion diseases: a review of the interactions of copper, manganese and zinc with the prion protein     

Leach SP  Salman MD  Hamar D 《Animal health research reviews / Conference of Research Workers in Animal Diseases》2006,7(1-2):97-105

Transmissible spongiform encephalopathies (TSEs) are a family of neurodegenerative diseases characterized by their long incubation periods, progressive neurological changes, and spongiform appearance in the brain. There is much evidence to show that TSEs are caused by an isoform of the normal cellular surface prion protein PrPC. The normal function of PrPC is still unknown, but it exhibits properties of a cupro-protein, capable of binding up to six copper ions. There are two differing views on copper's role in prion diseases. While one view looks at the PrPC copper-binding as the trigger for conversion to PrPSc, the opposing viewpoint sees a lack of PrPC copper-binding resulting in the conformational change into the disease causing isoform. Manganese and zinc have been shown to interact with PrPC as well and have been found in abnormal levels in prion diseases. This review addresses the interaction between select trace elements and the PrPC.  相似文献   

Feed supplementation prevents post-conception decline in milk progesterone concentrations associated with production stress in dairy buffaloes (<Emphasis Type="Italic">Bubalus bubalis</Emphasis>)     

Sarzamin Khan  Muhammad Subhan Qureshi  Nazir Ahmad  Muhammad Amjed  Muhammad Younas  Altafur Rahman 《Tropical animal health and production》2009,41(7):1133-1142

The onset of pregnancy may be associated with hormonal changes and decline in milk yield of buffaloes. To investigate this, forty lactating buffaloes from 1st to 23rd weeks post-conception were selected. The animals were assigned to three treatments: PRT, PRS, NPRT and three milk yielding groups HMY, 66 to 75 l/week, n = 12; MMY, 56 to 65 l/week, n = 16; LMY, 46 to 55 l/week, n = 12). Milk samples were collected on alternate weeks and analyzed with ultrasonic milk analyzer. EIA was used for milk progesterone concentrations. Group means were compared and correlation analysis was conducted. Progesterone concentrations increased in almost similar pattern with the advancing weeks post-conception. The high and low yielder showed greater progesterone concentrations in the supplemented than the animals on traditional ration (P < 0.001). Progesterone concentrations correlated positively with fat (%), negatively with milk yield, protein (%) and lactose (%). Decline in milk yield became drastic when progesterone concentrations rose above 6.44 ng/ml. The pregnant animals on traditional ration exhibited a sharper decline in milk yield with the increasing progesterone concentrations as compared to pregnant animals with supplemented ration. It is concluded that concentrates supplementation induced a raise in progesterone levels. Progesterone concentrations and milk yield showed an inverse relationship.  相似文献   

Induction of heat-shock proteins and phagocytic function of chicken macrophage following in vitro heat exposure.     

L Miller  M A Qureshi 《Veterinary immunology and immunopathology》1992,30(2-3):179-191

The protein profiles and phagocytic ability of Sephadex-elicited chicken peritoneal macrophages were examined following heat-shock exposure. Macrophage cultures were exposed to various temperatures, time exposures and recovery periods. Densitometric analysis of SDS-PAGE autoradiographs revealed that heat-induced macrophages synthesized three major (23, 70 and 90 kD) heat-shock proteins (HSPs). The optimal temperature and time for induction of these HSPs was 45-46 degrees C for 1 h, with a variable recovery period for each HSP. Macrophages exposed to 45 degrees C for 30 and 60 min were significantly depressed in phagocytosis of uncoated sheep erythrocytes (SE) under 45 degrees C incubation conditions. However, phagocytosis of antibody-coated SE was not affected when compared to 41 degrees C control cultures. Macrophages allowed to recover at 41 degrees C following heat-shock exhibited no alterations in their phagocytic ability for either antibody-coated or uncoated SE. This study suggests that heat shock induces three major HSPs in chicken peritoneal macrophages in addition to maintaining their Fc-mediated phagocytic function while significantly depressing their nonspecific phagocytosis.  相似文献   

Integrated hydrologic-economic modelling for analyzing water acquisition strategies in the Murray River Basin     

Mohammed Mainuddin  Mac Kirby  M. Ejaz Qureshi 《Agricultural Water Management》2007,93(3):123-135

We describe a coupled hydrologic-economic spreadsheet model for the Murray-Darling Basin that allows analyses of water allocation and use by different sectors including agriculture and environment under alternative policy scenarios. The model is a simple, lumped optimisation model which includes partitioning of rainfall into runoff and evapotranspiration, a reach by reach water balance of the river system, irrigation demand and revenue generation. Groundwater is not considered because groundwater use is a small part of the overall water use. The model is used to optimize profit, diversions and flows subject to hydrological and economic constraints determined by the policy scenario.We use the model to examine approaches of acquiring water for reallocation to the environment, and their impacts on irrigation water use and regional income from agriculture. We show that the optimal approach for acquisition depends on: economic factors, including the cost of water and the profits generated by its use; institutional factors, such as restrictions to trade between regions; and, hydrological factors, particularly the connectivity of and losses within the river network.The volume of water to be acquired does not, in general, equal the volume to be allocated. For a downstream site, water must be acquired from upstream, and more water must be acquired than is to be allocated: the volume acquired is that to be allocated plus transmission losses between the locations of acquisition and allocation. For upstream sites, it is optimal to acquire some water from downstream, and less water must be acquired than is to be allocated: the volume acquired is that to be allocated, less the transmission losses no longer incurred between the locations of acquisition and allocation.The volumes of water that must be acquired to satisfy an allocation target and maintain flows in the river system are affected by restrictions on trade between sub-catchments.  相似文献