Animal performance and economic comparison of novel and toxic endophyte tall fescues to cool-season annuals     

Beck PA  Gunter SA  Lusby KS  West CP  Watkins KB  Hubbell DS 《Journal of animal science》2008,86(8):2043-2055

Increased costs of annual establishment of small grain pasture associated with fuel, machinery, and labor are eroding the profitability of stocker cattle enterprises. Interest has therefore increased in development of cool-season perennial grasses that are persistent and high quality. This study occurred on 24 ha (divided into thirty 0.81-ha paddocks) located at the University of Arkansas Division of Agriculture Livestock and Forestry Branch Station, near Batesville. Two tall fescue (Festuca arundinacea Schreb.) cultivars infected with novel endophytes (NE), Jesup infected with AR542 endophyte (Jesup AR542), and HiMag infected with Number 11 endophyte (HM11) were established in September 2002. Jesup AR542 and HM11 were compared with endemic endophyte Kentucky 31 (KY-31) tall fescue; wheat (Triticum aestivum L.) and cereal rye (WR, Secale cereale L.) planted in September 2003, 2004, and 2005; and annual ryegrass [RG, Lolium perenne L. ssp. multiflorum (Lam.) Husnot] planted in September 2004 and 2005. Each year, 3 steers (3.7 steers/ha) were placed on each pasture for fall and winter grazing, and 5 steers (6.2 steers/ha) were placed on each pasture for spring grazing. Animal performance is presented by year in the presence of a year x treatment interaction (P < 0.01). Body weight gain per hectare of steers grazing NE tall fescue was greater (P < 0.01) than those of KY-31 and WR during 2003 to 2004, whereas in 2004 to 2005, BW gain per hectare of steers grazing NE and RG did not differ (P < or = 0.29) and was greater (P < 0.01) than that of WR, which was greater (P < 0.01) than that of KY-31. During 2005 to 2006, BW gain per hectare was greater (P < 0.01) for steers grazing RG than those of NE and WR, which did not differ (P > or = 0.14). Body weight gain per hectare was least (P < 0.01) for steers grazing KY-31. Average net return of NE tall fescue was greater (P < 0.01) than KY-31, but profitability of NE did not consistently differ from cool-season annuals. Across the 3-yr study, NE tall fescue produced net returns per hectare of $219; this level of profitability would require 4 yr for a new planting of NE tall fescue to break even. Novel endophyte tall fescues offer potential benefits related to decreased risk of stand establishment of annual forage crops, longer growing season, and acceptable animal performance.  相似文献   

Suggested guidelines for immunohistochemical techniques in veterinary diagnostic laboratories     

José A Ramos-Vara  Matti Kiupel  Timothy Baszler  Laura Bliven  Bruce Brodersen  Brian Chelack  Stefanie Czub  Fabio Del Piero  Sharon Dial  E J Ehrhart  Tanya Graham  Lisa Manning  Daniel Paulsen  Victor E Valli  Keith West 《Journal of veterinary diagnostic investigation》2008,20(4):393-413

This document is the consensus of the American Association of Veterinary Laboratory Diagnosticians (AAVLD) Subcommittee on Standardization of Immunohistochemistry on a set of guidelines for immunohistochemistry (IHC) testing in veterinary laboratories. Immunohistochemistry is a powerful ancillary methodology frequently used in many veterinary laboratories for both diagnostic and research purposes. However, neither standardization nor validation of IHC tests has been completely achieved in veterinary medicine. This document addresses both issues. Topics covered include antibody selection, fixation, antigen retrieval, antibody incubation, antibody dilutions, tissue and reagent controls, buffers, and detection systems. The validation of an IHC test is addressed for both infectious diseases and neoplastic processes. In addition, storage and handling of IHC reagents, interpretation, quality control and assurance, and troubleshooting are also discussed. Proper standardization and validation of IHC will improve the quality of diagnostics in veterinary laboratories.  相似文献   

Effect of pre-calving zeolite, magnesium and phosphorus supplementation on periparturient serum mineral concentrations     

Pallesen A  Pallesen F  Jørgensen RJ  Thilsing T 《Veterinary journal (London, England : 1997)》2008,175(2):234-239

The objective of this study was to test whether supplementing dry cow rations with phosphorus (P) and magnesium (Mg) would interfere with the beneficial effect of zeolite supplementation on the periparturient blood calcium (Ca) concentration in dairy cattle. Three groups (A-C) of 10 Danish Jersey cows were each given the following daily supplements from 2 weeks before the expected date of calving until actual calving: group A: zeolite, monoammonium phosphate, standard dry cow mineral and vitamin mix, containing 61g magnesium phosphate; group B: zeolite, standard mineral and vitamin mix without the magnesium phosphate and group C: standard mineral and vitamin mix, monoammonium phosphate. All cows in group B had an apparently less variable serum calcium concentration around calving with no cases of milk fever and no subclinical hypocalcaemia or hypomagnesaemia recorded. In contrast, a parturient drop in blood Ca was seen in group A as well as group C. In group A, one cow was hypocalcaemic at calving, and developed milk fever. In group C, 12 blood samples, representing six cows, were hypocalcaemic, and three of these cows were treated for milk fever. All groups remained normomagnesaemic and there were no significant differences in blood Mg across groups. In conclusion, the combined P and Mg supplementation in addition to zeolite supplementation did not increase the serum Mg level (forage Mg 16.9g/day; 0.21% of DM). Combined P and Mg supplementation reduced the zeolite-induced hypophosphataemia but also reduced the stabilising effect of zeolite on parturient serum Ca.  相似文献   

Antibiotic resistance and molecular characteristics of <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> isolated from backyard-raised pigs and pig workers     

Asabe Halimat Momoh  Jacob K. P. Kwaga  Mohammed Bello  Anthony K. B. Sackey  Anders Rhod Larsen 《Tropical animal health and production》2018,50(7):1565-1571

Staphylococcus aureus is a commensal and pathogenic bacterium with impact on public health and livestock industry. The study investigated nasal carriage, antibiotic resistance, and molecular characterization of S. aureus in pigs and pig workers. Nasal swabs from 300 backyard-raised pigs and 101 pig workers were used for the study. Resulting isolates were confirmed using MALDI-TOF MS, tested for antibiotic resistance, and three different multiplex PCRs were used to detect enterotoxin, mecA, spaA, scn, and pvl genes. spa typing was used to annotate the isolates into MLST clonal complexes (CC). Structured questionnaire was used to access possible risk factors for S. aureus carriage. The prevalence of S. aureus in pigs and pig workers were 5.3 and 12.9%, respectively. The isolates were resistant to beta-lactams (97%), tetracycline (62%), sulfonamide (52%), aminoglycoside (20.6%), fluoroquinolone (24%), and mupirocin (3.4%). Twenty seven (93%) of the isolates carried scn, 7(24%) pvl, and 12 (41%) enterotoxin genes, respectively. Questionnaire survey showed medical-related occupation of household members was associated (p?<?0.5) with S. aureus carriage. This study suggests the presence of human multidrug resistant strains of S. aureus, high carriage of pvl, and enterotoxin genes, and CC5, CC15, and CC152 were the CC-groups shared among pigs and pig workers.  相似文献   

Prevalence of interfering antibodies in dogs and cats evaluated using a species‐independent assay          下载免费PDF全文

Daniel Bergman  Anders Larsson  Helene Hansson‐Hamlin  Anna Svensson  Bodil Ström Holst 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2018,47(2):205-212

Background

Interfering antibodies in human serum and plasma are known to react with mammalian antibodies in immunoassays and cause false‐positive test results. Although this phenomenon was recently shown in companion animals, knowledge regarding immunoassay interference in veterinary medicine is very limited.

Objectives

The aims of this study were to set up a species‐independent immunoassay procedure to detect interference in serum samples, to screen for interference in a cross‐section of canine and feline patient samples from an animal hospital, and to determine if the detected interference could be neutralized using an immunoassay based on nonmammalian reagents.

Methods

A 2‐site sandwich‐type interference assay was set up using commercially available mouse reagents. A total of 369 serum samples from 320 dogs and 263 samples from 218 cats were analyzed using the interference assay. Multiple samples were submitted from 36 dogs and 39 cats. Nineteen samples identified as interference‐positive were analyzed in an assay using chicken antibodies.

Results

Interference was detected in samples from 28 dogs (9%) and 10 cats (5%) screened with the interference assay. Except for 1 cat, consistent results were obtained for all 75 dogs and cats that submitted more than 1 sample. The interference was eliminated when analyzed in the chicken‐based assay (P < .001).

Conclusions

Substances with reactivity toward mouse IgG can be detected in serum samples from dog and cat patients using a 2‐site interference assay. The detected substances are most likely interfering antibodies, possibly originating from immunization with other mammalian species.  相似文献   

A tale of two wildfires; testing detection and prediction of invasive species distributions using models fit with topographic and spectral indices     

Amanda M. West  Paul H. Evangelista  Catherine S. Jarnevich  Darin Schulte 《Landscape Ecology》2018,33(6):969-984

  相似文献   

Photosynthesis,leaf conductance,and water relations of cowpea under saline conditions   总被引：1，自引：0，他引：1  

D. W. West  G. J. Hoffman  M. J. Fisher 《Irrigation Science》1986,7(3):183-193

Summary Cowpea (Vigna unguiculata L.), grown widely under both irrigated and dryland conditions, is well adapted to drought and high temperature and is moderately salt tolerant. Data on photosynthetic response and regulation of water relations in cowpea under salinity stress is lacking. Therefore, in conjunction with a field plot experiment to establish the leaching requirement of cowpea, measurements were made of carbon dioxide assimilation rates (A) by ¹⁴CO₂ uptake, leaf conductances to H₂O (g₁) by tritum uptake, and to CO₂ (g), and leaf total water potential (_t ¹) and osmotic potential ( ¹).Cowpeas, grown in field plots containing Pachappa fine sandy loam (mixed, thermic, Mollic Haploxeraff), were irrigated daily with saline water (1,350 mg 1^–1 total salt concentration) to achieve leaching fractions of 0.17, 0.13, 0.09, 0.07, and 0.02. Cowpea maintained high leaf water potentials, high rates of CO₂ assimilation and high leaf conductances under moderately saline conditions (high leaching). Values of _t ¹ and ¹ for high leaching were consistently 50 to 200 J kg^–1 higher than for low leaching throughout the day. Calculating ¹ at full leaf turgor eliminated diurnal variation in ¹. As leaching decreased, however, A, g₁, and g, decreased significantly. About 45% of the 1°C assimilated by the leaf was incorporated rapidly into ethanol insoluble compounds. The relationship between A and g₁ for cowpea was similar to that reported for other crops.Contribution from the US Salinity Laboratory, USDA-ARS, 4500 Glenwood Dr., Riverside, CA. 92501, USA  相似文献   

Effect of the ratio of teaser rams used prior to breeding on the reproductive performance of ewe hoggets     

Kenyon PR  Morel PC  Morris ST  Burnham DL  West DM 《New Zealand veterinary journal》2007,55(6):342-345

AIM: To determine the effects of the ratio of vasectomised (teaser) rams to ewe hoggets used prior to breeding on the breeding performance and pregnancy rate of ewe hoggets. METHODS: Romney-composite ewe hoggets (n=1,180), 7-8 months of age, were randomly assigned to one of five treatment groups (Day 1) and either exposed to harnessed teaser rams at a teaser-ram:ewe-hogget ratio of 1:32 (n=193 hoggets), 1:66 (n=199), 1:98 (n=197), or 1:197 (n=395), for 17 days prior to the breeding period, or not exposed to teasers (unteased; n=196). Harnessed entire rams were then introduced for the duration of two oestrous cycles (34 days). Using crayon marks, ewe hoggets were identified as having been mated during the first 17 days only, during the second 17 days only, during both 17-day periods, or not mated. Hoggets were weighed on Days 1 and 18. All ewe hoggets were scanned for pregnancy using ultrasound, 57 days after the end of the breeding period. RESULTS: Hogget groups did not differ in liveweight at Day 1, but at Day 18 hoggets exposed to teasers at a ratio of 1:66 were lighter, and those exposed to teasers at a ratio of 1:32 were heavier than all other groups by up 3.0 kg (p<0.05). Unteased ewe hoggets were less likely to be pregnant to the first 17 days of breeding compared with all teased groups, by at least 16.4% (p<0.05). Over the entire 34-day breeding period, however, only those teased at a ratio of 1:32 were more likely to be pregnant, by 11.9%, than unteased hoggets (p<0.05). Within the teased hogget groups, there were no differences between groups for either the percentage mated in the first 17 days of breeding only, or those pregnant to either the first 17 days of breeding only or the entire breeding period. CONCLUSIONS: The results of this study indicate that teaser-ram:ewe-hogget ratios as high as 1:197 can increase the percentage of ewe hoggets bred in the first 17 days of mating by at least 16.4%. Across the range of ratios used there was little difference in breeding pattern or pregnancy rate, although results might suggest ratios 1:98.  相似文献   

Modeling wood fiber deformation caused by vapor expansion during steam explosion of wood     

Muhammad Muzamal  E. Kristofer Gamstedt  Anders Rasmuson 《Wood Science and Technology》2014,48(2):353-372

Steam explosion is a process used to enhance enzyme penetration and digestibility of wood. Wood chips are processed with high-pressure steam for a limited time, and the bonding between polysaccharides and lignin is weakened. After this processing, the pressure is rapidly reduced to induce steam explosion where the vapor inside a fiber expands and exerts pressure on the fiber walls. This pressure causes fiber deformation and breakage. In this study, fiber deformation caused by vapor expansion was simulated by single wood fibers using finite element modeling. When pressure is applied inside a fiber, it is likely to break from the corner and midway between two adjacent corners. The fiber is modeled with four layers (P, S1, S2, and S3). Although the P, S1, and S3 layers are very thin, they significantly prevent fiber deformation. The fibers with a thin wall and a low micro-fibril angle (MFA) deform more than the fibers with a thick wall and a higher MFA. It was found that the shape of the fiber plays an important role in its deformation. The areas of localized strain are the most likely places for fiber splitting. Essentially, fiber wall damage is more likely to occur in (1) thin-walled fibers, i.e., earlywood, (2) fibers with damaged P and S1 layers, (3) fibers with low MFAs, and (4) fibers with irregular cross-sections. Different chemical pretreatments, fractionation procedures, and selections of raw materials can accordingly be considered to produce easily steam-exploded materials.  相似文献   

Innovation diffusion of new wood-based materials – reducing the “time to market”     

Anders Roos  Mikael Lindström  Lena Heuts  Nippe Hylander  Erik Lind  Christian Nielsen 《Scandinavian Journal of Forest Research》2014,29(4):394-401

The purpose of this study is to understand the innovation diffusion of new wood-based materials, “from lab to market,” to identify the success factors and barriers to market introduction, and to reveal important factors for the success of commercialization. Examples are given from target markets in the furniture, appliance, and automotive sectors. This study is based on three qualitative interview studies in Sweden from 2010 to 2012. The analysis showed that the diffusion process of a new bio-based material normally takes up to 10 years or even more. There are only a few companies along the supply chain whose specialized function is finding new materials. However, the automotive industry regularly monitors the development of new materials. Industrial customers of materials generally obtain information about biobased materials from suppliers, exhibitions, conferences, professional contacts, industry magazines, digital media, customers, and partners in development projects. Different industry sectors apply specific material requirements. Regulations regarding safety issues have a high priority, and the interviewees believed that environmental considerations will increase with time. If the materials are equal in other quality dimensions, environmental performance may cast the deciding vote. Recommendations for a faster diffusion cover the right mix of competences, financing, regulations, creativity, and support from the leadership.  相似文献