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Meals & nutrition

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CATTLE BARRIER V1.0



Most of the dietary sulfur ingested by ruminant animals is converted to sulfide by rumen microbes, primarily the rumen bacteria. The S-containing amino acids are fermented to sulfide, while sulfate is also reduced to sulfide by ruminal sulfate-reducing bacteria (SRB) [3]. Although SRB are comprised of a small population of bacteria in the rumen, it can have a significant impact on the cattle fed with a high sulfur diet, such as DDGSs.




CATTLE BARRIER V1.0


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Increased DDGSs content in the diet also increases hydrogen sulfide (H2S) production by rumen SRB, increasing the risk of sulfide-induced polioencephalomalacia (PEM) [1]. The rumen epithelium plays an important role in the nutrient absorption and defense in ruminants. The normal barrier function of rumen epithelium is very important to ensure their health. However, it is unclear if H2S damages the rumen epithelium and affects the health of the animal, leading to an inflammatory response.


Of feed samples, 220 mg, same as the ration fed to fistula cattle, with the right sulfur levels were transferred to 100 mL glass syringes (Deli Electric Power Equipment, Shijiazhuang, Hebei, China), pre-incubated at 39 C, with each treatment containing nine syringes. Of the inoculum, 30 mL was injected into each syringe with a Varispenser (Eppendorf AG, Hamburg, Germany) and then incubated on an automatic shaker (Jie Cheng Experimental Apparatus, Shanghai, China), in a water bath at 39 C for 72 h. During the incubation, the volume of cumulative gas production (GP) was recorded manually at the time points of 0, 2, 4, 6, 8, 10, 12, 18, 24, 30, 36, 42, 48, 60, and 72 h.


A healthy, stratified, and flat epithelium of the rumen is usually covered by keratinocytes, which acts as a primary physical barrier to prevent the lower rumen epithelial cells from being invaded by toxic substances. Our results show that a high sulfur diet can cause excessive keratinization of rumen epithelium and cuticle accumulation, which changes the function of the epithelial barrier and reduces the short-chain fatty acid transport [31]. This may be related to the high concentration of propionic acid and butyric acid in the rumen that promotes excessive proliferation or differentiation of the rumen epithelial cells [32]. According to our results, the concentration of propionic acid and butyric acid in the rumen increased significantly with high sulfur diet, which is one of the reasons for rumen epithelial keratosis.


We thank the staff and students of Beef cattle Research Center of China Agricultural University for their help with animal care and sampling. This manuscript has been released as a pre-print at Research Square (DOI:10.21203/rs.3.rs-47899/v1).


Each cattle stop is available in sizes up to 14 feet, but can also be added onto existing cattle guards in order to meet road width requirements. Available in sizes up to 14 feet, and multiple colors, a Powder River cattle stop is also available with a concrete casting set.


Figure 1. Experimental site (not to scale). The home pens were used to house cows during the neckband acclimatization and pasture regrowth periods. Water and shade were accessible in all home pens with a feed bunk in each used to feed out hay daily at maintenance level. The cattle yards were accessible from the home pens and contained multiple smaller pens and a cattle crush. The annual ryegrass paddock was used for both the training period and strip grazing. water; fixed fence; gate way.


Lily N Edwards-Callaway, M Caitlin Cramer, Caitlin N Cadaret, Elizabeth J Bigler, Terry E Engle, John J Wagner, Daniel L Clark, Impacts of shade on cattle well-being in the beef supply chain, Journal of Animal Science, Volume 99, Issue 2, February 2021, skaa375,


Bovine tuberculosis (bTB) is a major economic disease of livestock worldwide. Despite an intensive, and costly, control program in the United Kingdom, bTB continues to persist. Vaccination can provide some protection to cattle, but is currently illegal within the European Union due to the interaction of BCG with the action of the tuberculin skin test. The EU has signaled that changes in legislation will require field validation of BCG as a supplement to existing controls. A particular concern is that the imperfect sensitivity of prospective DIVA tests for vaccinates may increase the chances of infection being missed within herds. However, we demonstrate that high DIVA specificity will also be essential in order for farmers to see a protective herd level benefit of vaccination in terms of the frequency of tests they are subjected to and number of animals condemned. Field validation of the DIVA test will be an essential prerequisite to use of BCG in the field. Our estimated target specificity provides an important criterion for validation of prospective DIVA tests before deployment in the field.


Funding: This study was funded by Defra project SE3127 and uses nationally collected incidence and cattle-movement data sets held by Defra. The funders had no role in study design, data analysis, decision to publish, or preparation of the manuscript.


Human vaccine Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccination has been shown to induce significant levels of protection in cattle in a large number of experimental studies and field trials since 1912 (reviewed in [1]). More recent laboratory studies have demonstrated significant reductions in the development and presentation of visible lesions after challenge with M. bovis [2]. Recent field trials and experiments under natural transmission conditions have also reported its effectiveness, although with variable levels of protection [3], [4] ranging from no effect to up to individual protective efficacies of 68% [5]. However, vaccination is not currently used as part of a national bovine TB control program. By far the most important historical barrier to the use of cattle vaccination is the interference of BCG with the specificity of the tuberculin skin test [6], which is the cornerstone of surveillance and eradication strategies [7]. A new generation of diagnostic DIVA tests that can Differentiate Vaccinated from Infected Animals [8], [9] opens up the opportunity for the use of BCG within current control programs. For vaccination to be feasible economically and useful within the context of European legislation, the benefits of vaccination must be great enough to outweigh any increase in testing associated with the efficiency of DIVA testing. In this study we use rigorously estimated within-herd transmission models [7] to explore scenarios for the supplemental use of BCG vaccination in Great Britain. We estimate the DIVA test characteristics necessary to see a protective herd level benefit of vaccination when used within the current statutory system of testing.


Control of M. bovis infection of cattle in Great Britain, and internationally, generally depends on active disease surveillance through repeated testing of herds using tuberculin. The sequence of testing used has been designed around the known imperfect sensitivity and specificity of the tuberculin test. A fundamental challenge to the evaluation of diagnostic tests for bTB in GB is that test-positive animals are slaughtered irrespective of development of physical symptoms of disease. In the absence of a gold standard, the sensitivity and specificity of diagnostic tests can only be directly measured relative to culture confirmation of visible lesions. In this paper, unless otherwise stated, we define (and estimate) the sensitivity and specificity of diagnostic tests relative to the true infection status of animals. In our modelling framework we therefore define the specificity of a test as the complement (1-pFP) of the probability of obtaining a false-positive test result (pFP).


Due to the indirect protection afforded by vaccination through herd immunity [18], vaccination is often the most cost-effective method of controlling infectious diseases. Cattle vaccination has been proposed as a supplementary method to reduce the duration of time that herds are under restrictions and the number of animals removed during testing. However, such use poses a particular challenge for M. bovis infection where the known interference of BCG with tuberculin testing has resulted in cattle vaccination for bTB being prohibited in the EU. Tuberculin testing is used to demonstrate progress towards national eradication and also as the basis of international trade in cattle. Thus, vaccinated animals that demonstrate sensitivity to tuberculin have to be treated as infected animals and slaughtered.


There has recently been movement in this position by the EU and requirements for changes in legislation to allow cattle vaccination have been outlined, essentially requiring field evaluation of both BCG efficacy and DIVA test characteristics. Recent advice from the European Food Safety Authority [19], commissioned by the EU, emphasized the importance of demonstrating that BCG is efficacious and that DIVA tests can be shown to have a comparable sensitivity to tuberculin testing. However, a key factor overlooked in this report was that the currently viable DIVA tests are based on the gamma-interferon platform, which is known to have a lower specificity than SICCT testing [8]. This raises the concern that the use of BCG vaccination and DIVA tests under the current regulatory system of testing may lead to vaccinated herds effectively unable to escape restrictions once a single reactor animal has been detected.


The compartmental models developed in [7] assumed that the movement of animals on and off a herd occurred at constant herd level turnover rate sampled from the Cattle Tracing System (CTS). As a consequence of this approximation, individuals spend an exponentially distributed duration of time on herds. In practice the distribution of residence times on herds can vary considerably between different business models impacting on the herd level rates of removal of residual infection from herds. Implementing these models within an individual based framework allows us to model more realistic residency times of individuals on herds and more accurately capture the variation in turnover rates between herds. An additional benefit of the individual based model framework is that we can also incorporate new evidence for the relative risk of infection with age and probability of reactor animals demonstrating visible lesions recently estimated by [21] (Fig. 1). After adjusting for testing patterns, we found that young beef and dairy animals experience a similar infection risk that peaks at 36 months before falling and plateauing for animals older than five years (Fig. 1A, Table 1). Although the infection risk is lowest in cattle under 12 months, the highest proportion of skin test positive animals is found to have visible lesions when they are examined at slaughter (Fig. 1B, Table 2). 041b061a72


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