笼养蛋鸡疲劳症的发生及控制   总被引：2，自引：0，他引：2  

黄志宏 《当代畜牧》2001,(2)

笼养蛋鸡疲劳症又称笼养蛋鸡骨质疏松症 ,是一种在高产笼养产蛋母鸡群中广泛流行的疾病 ,最常发生在产蛋高峰期的母鸡 ,主要由于钙质消耗严重而发病。发病严重的鸡群如不采取适当措施 ,死亡淘汰率可超过 1 0 % ,值得引起人们的重视。1　病因及发病情况母鸡产一个蛋需要 2 .0～ 2 .2克钙形成蛋壳 ,形成蛋黄及蛋清仅需钙 30毫克。饲料中的钙从肠道吸收后被转送至蛋壳腺或暂时贮存在髓质骨。蛋壳形成所需的钙可以从饲料中供给 ,但如果不能从饲料中吸收足够的钙 ,母鸡就会动用髓质骨中的钙。在极端情形下 ,骨骼钙的损失多达其钙含量的 30 %～ 35…  相似文献   

西半球家畜虫媒病毒性脑脊髓炎     

Walt.  TE 王守忠 《国外兽医学(畜禽传染病)》1993,13(3):46-49,41

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缺硼对向日葵籽实与油分生产和早期幼苗生长的影响     

Smith  TE 禹航 《国外农学:油料作物》1993,(3):49-51

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A nutritional myopathy enzootic in a group of yearling beef cattle          下载免费PDF全文

Smith DL  Palmer SJ  Hulland TJ  McSherry BJ  Blackwell TE 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(12):385-386,387-390

Steers and bulls under feedlot conditions and on an apparently adequate ration developed transitory signs of diarrhea and unthriftiness. One animal became recumbent. Sick and clinically normal animals in the group had elevated serum creatine kinase and aspartate aminotransferase enzyme values and degenerative changes in muscle fibers on biopsy. Feed analysis was carried out and the animals were monitored over several weeks by means of muscle biopsy and serum enzyme analysis as well as by postmortem examination at slaughter. Subclinical myopathy was found in several animals and was thought to be related to low vitamin E content in the high moisture corn ration.  相似文献   

The modern role of meat inspection and food hygiene   总被引：2，自引：2，他引：0  

Feltmate TE 《The Canadian veterinary journal. La revue veterinaire canadienne》1985,26(1):29-32,33

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Atmospheric CO(2) and the ratio of intercellular to ambient CO(2) concentrations in plants     

Ehleringer JR  Cerling TE 《Tree physiology》1995,15(2):105-111

Much attention is focused today on predicting how plants will respond to anticipated changes in atmospheric composition and climate, and in particular to increases in CO(2) concentration. Here we review the long-term global fluctuations in atmospheric CO(2) concentration as a framework for understanding how current trends in atmospheric CO(2) concentration fit into a selective, evolutionary context. We then focus on an integrated approach for understanding how gas exchange metabolism responds to current environmental conditions, how it previously responded to glacial-interglacial conditions, and how it may respond to future changes in atmospheric CO(2) concentration.  相似文献   

Invertebrate lineages: crustacean phylogeny     

Bowman TE 《Science (New York, N.Y.)》1984,224(4644):53

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Life below the ross ice shelf, antarctica     

Lipps JH  Ronan TE  Delaca TE 《Science (New York, N.Y.)》1979,203(4379):447-449

Samples and observations under 420 meters of ice and 430 kilometers from the open sea on the Ross Ice Shelf at a water depth of 597 meters revealed an unusual assemblage of benthic organisms. Scavenging amphipods, an isopod, and fish were present but a living infauna was absent. The observations may be accounted for by sampling or spatial bias, or by extremely low or fluctuating trophic resources.  相似文献   

Evaluation of stocking density and subtherapeutic chlortetracycline on Salmonella enterica subsp. enterica shedding in growing swine     

Funk J  Wittum TE  LeJeune JT  Rajala-Schultz PJ  Bowman A  Mack A 《Veterinary microbiology》2007,124(3-4):202-208

The objective of this research was to determine the effect of stocking density and inclusion of subtherapeutic chlortetracycline in the diet on Salmonella fecal prevalence and antimicrobial resistance in growing swine. A 2 x 2 factorial design was employed on a privately owned commercial swine farm. Four finisher rooms were included in the study. Two of the rooms received 50 g/tonnes of chlortetracycline in the ration, two rooms received no antimicrobials in the feed. In each room, alternate pens were assigned to either high stocking density (0.60 m2/pig) or low stocking density (0.74 m2/pig). Pigs were placed in the finisher rooms at 10 weeks of age and followed for 6 weeks. Individual fecal samples were collected from the floors of each pen and cultured once weekly. Antimicrobial resistance phenotypes were determined. Data were analyzed using multilevel, multivariable logistic regression. Pigs fed chlortetracycline were at increased odds (OR 6.88, 95% CI 2.77-17.12) to shed Salmonellae. No other associations between treatments (CTC and stocking density) and Salmonella prevalence or reduced susceptibility to antimicrobials were identified. Variance in the odds of a fecal sample to be positive was distributed mostly at the lowest level, the individual fecal sample. The increased risk of shedding associated with inclusion of subtherapeutic chlortetracycline in swine diets is discordant with previous results by our group, suggesting farm or strain specific factors may impact this association. Understanding this risk may provide a potential intervention for controlling Salmonella pre-harvest.  相似文献   

A dynamic, optimal disease control model for foot-and-mouth disease: I. Model description     

Kobayashi M  Carpenter TE  Dickey BF  Howitt RE 《Preventive veterinary medicine》2007,79(2-4):257-273

A dynamic optimization model was developed and used to evaluate alternative foot-and-mouth disease (FMD) control strategies. The model chose daily control strategies of depopulation and vaccination that minimized total regional cost for the entire epidemic duration, given disease dynamics and resource constraints. The disease dynamics and the impacts of control strategies on these dynamics were characterized in a set of difference equations; effects of movement restrictions on the disease dynamics were also considered. The model was applied to a three-county region in the Central Valley of California; the epidemic relationships were parameterized and validated using the information obtained from an FMD simulation model developed for the same region. The optimization model enables more efficient searches for desirable control strategies by considering all strategies simultaneously, providing the simulation model with optimization results to direct it in generating detailed predictions of potential FMD outbreaks.  相似文献