Sub-acute ruminal acidosis: a multidisciplinary approach to understand and prevent a multifactorial disease
Lead Research Organisation:
University of Strathclyde
Department Name: Electronic and Electrical Engineering
Abstract
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Technical Summary
Sub-acute ruminal acidosis (SARA) affects some cattle herds, but not others, and individual animals within herds, but not others. The root cause of the dysfunction is the loss of control of ruminal and possibly intestinal pH. SARA is generally caused by grain feeding, but the basis of the variability requires better definition and the precise cause of inflammation and pathology remains uncertain. This project will monitor six beef and two dairy herds for nutrition and management and relate the information to post-mortem scores of ruminal wall lesions, liver abscesses and laminitis. The potential value of remote motion sensors in alerting farmers to problematic animals will be explored. Ruminal digesta and ruminal epithelial tissue samples taken post mortem will be analyzed by state-of-the-art microbiomic analysis based on 16S rRNA gene sequences, in order to identify significant differences in microbial communities in different animal types. Different Escherichia coli biotypes will be monitored. Bacteria will be isolated from least affected animals for their ability to inhibit the growth or adhesion properties of E. coli, on the basis that these animals may already possess bacteria that protect them from SARA. Candidate strains will be evaluated for their potential usefulness as probiotics to prevent or treat SARA. The hypothesis that soluble lipopolysaccharide (LPS) lies at the heart of the inflammation which results in pathology will be tested by measuring the quantities and nature of cell-free LPS in different animals. Possible feed additives that adsorb or break down LPS will be evaluated in digesta samples from badly affected animals. Demonstration animal trials will be carried out in the third year of the project to test the potential nutritional, management and feed-additive solutions identified by the project's results.
Planned Impact
A wide international spectrum of academic researchers will benefit from the project, because SARA is a widespread problem internationally. Researchers interested in ruminant health and welfare and those whose main interest is ruminant gut microbiology will be the primary beneficiaries. They will be able to translate the results to their own production conditions where SARA is endemic. The results will be of wider interest, however, because although SARA is a disorder that afflicts ruminant species, researchers interested more generally in inflammation that originates in the gastrointestinal tract of other species, including man, will benefit. Related fields include equine health and poultry production: researchers in these areas will build upon the novelty of this project to determine if the aetiology of their target diseases, in terms of microbiology, inflammatory factors and pathology compare. New research and research proposals for these different animal species could result. Medical researchers may benefit too: the concept of soluble LPS has not yet been explored in human disease, for example. One might speculate that soluble LPS may have an important, as yet uninvestigated, role in inflammatory bowel disease (IBD) in man. Our project may spark useful medical research in this area. Microbiome profiling will provide information about how diet and the individual animal affect numbers and species of methanogenic archaea in the rumen, thereby aiding research into greenhouse gas emissions from animal agriculture. Ruminal microbial ecology in UK ruminants is under-studied in the modern era: the project will help correct that deficiency.
Veterinary practitioners and public sector advisers from colleges of agriculture and levy bodies will benefit by being better equipped to advise farmers. The project will describe management and nutritional factors associated with variations in the incidence of SARA, information that farmers' advisers can use on-farm. Vets will be able to make better diagnosis of SARA and they will be able to suggest solutions from those feed additives coming out of the SARA project. The probiotic(s) will be useful to help prevent pathological problems in susceptible farms and animals. The adsorbants may be useful in prevention but also to treat the condition. The market potential for a successful feed additive is many millions of pounds. The advisors may consider the remote monitoring system a useful mechanism to monitor the success or otherwise of strategies to ameliorate SARA. The academic partner expert in remote broadband technology has a spin-out SME that will benefit if the technology is found to be generally useful in an on-farm situation. The companies selling these additives and devices will benefit commercially. Initially, those will be from within the consortium. However, as the results are disseminated, more companies in the UK and worldwide will take up the technologies.
Farmers will benefit economically. The beef industry nationwide has a value of £2.22bn at 2009 values. It follows that even a 5% overall loss of productivity caused by SARA may cost livestock producers £111M p.a. Dairying has a similar incidence of therefore the loss to farmers (and the UK economy) could easily exceed £200M p.a. The economic impact will be felt across the globe in countries that suffer from SARA in their ruminants, including the US (26% of mid-lactation cows suffer SARA), the Netherlands and Germany (18%). Livestock production in the UK will gain against its international competitors and, by retaining the IP in the UK, the economic competitiveness of the United Kingdom will be enhanced. Societal benefit will stem from improved economics and sustainability of food production and a healthier national herd. The livestock will benefit by being less subject to the distress of SARA, thus enhancing animal welfare.
Veterinary practitioners and public sector advisers from colleges of agriculture and levy bodies will benefit by being better equipped to advise farmers. The project will describe management and nutritional factors associated with variations in the incidence of SARA, information that farmers' advisers can use on-farm. Vets will be able to make better diagnosis of SARA and they will be able to suggest solutions from those feed additives coming out of the SARA project. The probiotic(s) will be useful to help prevent pathological problems in susceptible farms and animals. The adsorbants may be useful in prevention but also to treat the condition. The market potential for a successful feed additive is many millions of pounds. The advisors may consider the remote monitoring system a useful mechanism to monitor the success or otherwise of strategies to ameliorate SARA. The academic partner expert in remote broadband technology has a spin-out SME that will benefit if the technology is found to be generally useful in an on-farm situation. The companies selling these additives and devices will benefit commercially. Initially, those will be from within the consortium. However, as the results are disseminated, more companies in the UK and worldwide will take up the technologies.
Farmers will benefit economically. The beef industry nationwide has a value of £2.22bn at 2009 values. It follows that even a 5% overall loss of productivity caused by SARA may cost livestock producers £111M p.a. Dairying has a similar incidence of therefore the loss to farmers (and the UK economy) could easily exceed £200M p.a. The economic impact will be felt across the globe in countries that suffer from SARA in their ruminants, including the US (26% of mid-lactation cows suffer SARA), the Netherlands and Germany (18%). Livestock production in the UK will gain against its international competitors and, by retaining the IP in the UK, the economic competitiveness of the United Kingdom will be enhanced. Societal benefit will stem from improved economics and sustainability of food production and a healthier national herd. The livestock will benefit by being less subject to the distress of SARA, thus enhancing animal welfare.
Publications
C. Michie
(2015)
Measurement of rumen motility using a triaxial gyroscopic
Craig Michie (Author)
(2012)
oestrus detection in beef and dairy cattle
Jonsson NN
(2020)
Postmortem observations on rumen wall histology and gene expression and ruminal and caecal content of beef cattle fattened on barley-based rations.
in Animal : an international journal of animal bioscience
McCartney C A
(2014)
Caecal lipopolysaccharide concentrations and SARA pathology in beef cattle
Michie C
(2013)
Oestrus Detection in beef and dairy cattle
Thorup VM
(2016)
Lameness Affects Cow Feeding But Not Rumination Behavior as Characterized from Sensor Data.
in Frontiers in veterinary science
Description | Key Results (Task 3) The main ingredient of all the diets on the six farms was barley, which was grown and processed on each of the farms. The diets were diverse, despite being barley-based. Sugar beet pulp, soya hulls and a buffer against acidosis were only used on one farm each and yeast was used on all farms. Rumitech was included only on two of the high concentrate, high risk farms. The farm of origin was the dominant effect on the measured variables, almost all variables differing significantly among farms. The animals on the high risk diets had lower concentrations of short-chain fatty acids (SCFAs) and higher concentrations of lactate and LPS in the reticuloruminal fluid. The diameters of the strata granulosum, corneum and of the vasculature of the papillae were increased on the high-risk farms, as was the expression of the gene TLR4 in the ruminal epithelium, while the expression of IFN-? and IL-1ß was lower, as were the counts of CD3+ and MHCII+ cells. As the proportion of barley in the ration increased, so did the concentration of reticuloruminal and caecal lactate, reticuloruminal histamine, LPS and the thickness of the strata corneum and granulosum, while there was a reduction in the total SCFA concentration in the reticulorumen the expression of IFN-? and count of MHCII+ cells in the ruminal epithelium. Increasing the proportion of fines in the ration had mostly similar effects to increasing the proportion of barley, but in several cases, the effect was stronger and there was also an increase in the expression of NHE3 gene in ruminal epithelium. Despite variation among farms, there were few strong associations of gene expression variables with the other input or dependent variables. NHE3 expression was positively associated with the concentration of LPS in reticuloruminal fluid (r = 0.30, p < 0.05), and with the level of fines in the ration. IFN-? expression decreased as barley and fines in the ration increased. The levels of expression of the genes in the epithelium correlated moderately or highly with each other. They were not strongly correlated with the thickness of the stratum granulosum, nor with the density of CD3+ nor MHCII+ cells, nor lactate concentration in reticuloruminal or caecal fluid. A surprising result from this study was the lack of obvious pathology in the rumens that were examined. We used a gross scoring system with 5 categories but only 15 of 119 animals in total scored anything other than a baseline normal score ("A") for the variable "Pre-Score". We therefore combined the non-"A" categories for analysis and there was no strong relationship between the pre score of the ruminal mucosa with any of the factors considered in the study. This should not be taken as definitive evidence that there was no pathology in the rumens that we examined, but that none was detected using our matrix. The lack of clear-cut histological signs of pathology was consistent with this observation. As a consequence of the lack of any distinct pathology, one of the objectives of the study, to characterise the possible pathological features of the reticulorumen in cattle from divergently managed intensive beef finishing farms with high rates of concentrate feeding, was not able to be achieved. Nonetheless, elevated concentrations of LPS and lactate were seen in the reticulorumens of cattle on diets with high percentages of barley and fines. Of the dependent variables measured in this study, LPS and lactate concentrations are the best indicators of pathology, however without any independent marker for performance or health (eg daily live weight gain, feed intake, clear evidence of systemic illness) it was not possible to determine de novo thresholds at which LPS or lactate concentrations indicate pathology. A previously proposed threshold of mmol/l of lactate above which an animal is considered to be suffering from acute acidosis seems reasonable and would have been exceeded by 4% of the animals in this study. Key Results (Task 4 and Task 6) The microbial population of the rumen was found to be typical of an animal consuming a high starch diet. The population in the caecum was significantly different to that of the rumen and was less diverse. Furthermore, the microbial population in both the rumen and caecum seemed to be unique to individual farms. Previous research has shown that E. coli, which is a proteobacteria, is a potential driver of the inflammation associated with SARA. Surprisingly, there were negligible counts of E. coli in the rumen and caecum, and Proteobacteria in the caecum appeared to drastically reduce. Furthermore, the predominant proteobacteria species in the caecum actually belonged to the Moraxellaceae. This clade had not previously been characterised in the ruminant; however, previous research shows that it can have inflammatory properties. In addition, Moraxellaceae were more common in the caecum in animals who consumed feed that contained a high proportion of "dusty" feed (i.e. TMR <1.18 mm). There was also a relationship between the "dusty" feed and apparent inflammation of the rumen wall. The role of caecal Moraxellaceae and dusty feed on the caecum warrants further investigation. Farmer Facing Messages It is interesting that "dusty" feed appears to have a relationship with rumen inflammation and the presence of Moraxellaceae in the caecum. The negative effects of SARA could be reduced by changing physical treatment of the barley grain to avoid dust, and possibly clearing out dusty feed from the bottom of the food trough. Further Exploitation by Industry Industry will need to be aware of any subsequent effects on the caecum. Even if the rumen appears healthy, the caecum is less well adapted to cope. The study also highlights that E. coli may not be the only culprit and that other bacterial species may have an influence on the inflammation associated with SARA. |
Exploitation Route | Messages and industry exploitation • When challenged with high starch and low NDF diets, an inflammatory condition (SARA) can develop in cows before there are signs of reduced milk fat or reduced milk production. • Direct fed microbials, particularly Probios Complete and an Enterococus faecium strain used alone, increased reticuloruminal pH. • Traditional methods of diagnosing SARA on the basis of reticuloruminal pH are likely to be too stringent and will not correctly identify some farms on which SARA is contributing to disease. • Previously reported associations of dietary challenge using high concentrations of soluble carbohydrates with lipopolysaccharide and histamine concentrations in the reticuloruminal fluid were confirmed. • Previously reported associations of dietary challenge using high concentrations of soluble carbohydrates with inflammatory markers in the blood were confirmed. • One or more of the associated blood or reticuloruminal fluid variables might be developed as a potential bio-markers for the early identification of diets that contain excessive soluble carbohydrate relative to effective fibre. |
Sectors | Agriculture Food and Drink |
Description | Messages and industry exploitation (Task 3) There are three main messages from this study; Firstly, despite a reasonable expectation of some degree of equivalence among farms due to their similar location, management and broad nutritional inputs, farm to farm variation in rations and practices was wide and the effects of individual farm factors on animal physiology dominated any other factors that were measured. Some of the potential confounding factors at the level of the farm include specific nutritional components, mixing and feeding practices, stocking density, faecal or bedding management, the source of cattle, variation in their genotype and enteric microbiome, health and nutritional management before arrival at the farm of origin. This observation has implications for the design and interpretation of future studies on the impact of interventions in the field, in which a higher level of replication is required than is required for conventional, controlled experimental studies. It also implies a need to consider the effects of any nutritional intervention as part of a complex, interactive network of input factors. Secondly, the study provides an insight into the adaptive capacity of cattle. The animals in this study were those that made it to slaughter with the rest of their cohort and over the three months or so that they were on feed they had all successfully adapted to a highly challenging diet with little or no evidence of pathology, despite the fact that 4% of them had reticuloruminal lactate concentrations that were consistent with acute acidosis. Future studies on the effects of high levels of soluble carbohydrate supplementation or seeking to describe pathology associated with SARA would be more effective if they were to focus on the animals that failed to meet performance targets. The third message from the study is that the proportion of fines in concentrate-based total-mixed rations is a strong driver of the reticuloruminal SCFA, lactate and histamine concentrations. It follows that as much care is required with presentation of the concentrate diet as with its formulation. An understanding that rumination signatures can be detected using collar technology has inspired organisations such as Harbro to examine how this signature can be translated into information relevant to the farming community |
First Year Of Impact | 2014 |
Sector | Agriculture, Food and Drink |
Impact Types | Economic |
Title | Sub Acute Rumen Acidosis (SARA): a study relating rumen pH value and low activity. |
Description | "This archive contains collar based accelerometer data that was used to identify changes in animal behaviour associated with the onset of SARA as determined by a drop in rumen pH value measured using a rumen pH bolus. The measurements were made on cattle at Cochno farm Oct to Dec 2015. These are associated with rumen pH measurements. Where there are strong rumination pH changes, these can often be associated higher incidences of low activity. This is currently being analysed. The experiments took place between Oct-Dec 201. Additional data is provided running to March 2016." |
Type Of Material | Database/Collection of data |
Provided To Others? | No |
Impact | Not Applicable |
Description | Joint research with SRUC, Scotland's Rural College |
Organisation | Scotland's Rural College |
Department | Animal and Veterinary Sciences |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | Joint research |
Collaborator Contribution | Joint research |
Impact | Joint research and collaboration |
Start Year | 2012 |
Description | Joint research with University of Aberdeen |
Organisation | University of Aberdeen |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | University of Strathclyde researchers worked on this project with researchers from University of Aberdeen |
Start Year | 2012 |
Description | University of Kentucky |
Organisation | University of Kentucky |
Department | Department of Animal and Food Sciences |
Country | United States |
Sector | Academic/University |
PI Contribution | Research into animal welfare on Kentucky farm |
Collaborator Contribution | Data Analysis, animal monitoring |
Impact | research |
Start Year | 2015 |
Description | Advances in monitoring of livestock |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | Plenary talk at European Association of Animal Science, Warsaw August 2015. Contributors - Dave Ross, Craig Michie, Carol-Anne Duthie, Shane Troy, Ivan Andonovic. Presentation delivered by D Ross |
Year(s) Of Engagement Activity | 2015 |