Increased understandings of ruminal acidosis in dairy cattle

ABSTRACT Ruminal acidosis remains an important and prevalent disorder of economic and welfare concern to the dairy industry worldwide. There are inconsistencies in the diagnostic techniques and definitions of ruminal acidosis and a requirement for further information on the pathogenesis of ruminal acidosis, in particular in regard to the role of feed substrates, such as starch, sugar, and protein (Chapter 1). A greater understanding of changes to the microbiome during ruminal acidosis, feed management, and the possible synergistic effects of feed additive control agents is also required (Chapter 1). Consequently, the overall hypothesis of this thesis, which was supported, is that starch-, sugar-, and protein- or amino acid-based feed substrates would produce different ruminal and blood measures and distinct rumen bacterial community composition associated with different risks of ruminal acidosis. Secondly, that partial mixed ration feeding strategies and feed additive control agents would promote favorable ruminal conditions and reduce the risk of ruminal acidosis, which was also supported; however, whether feed additive control agents reduced the risk of ruminal acidosis was equivocal. Heifers exposed to a single feeding of grain and fructose had an increased risk of ruminal acidosis and accumulated ruminal lactate, compared to those fed grain only (Chapter 2). This highlights that diets with high sugar content should be fed with caution and increase the risk of ruminal acidosis when physically effective fiber is inadequate. Different oxidative stress responses were not observed among treatment groups of heifers fed single exposures of different substrates (Chapter 3) or different feed additives over a 20 d period (Chapter 7), but were evident in a heifer with acute clinical ruminal acidosis (Chapter 8). This suggests oxidative stress responses may only occur during acute clinical ruminal acidosis. Distinct ruminal bacterial community composition occurred among heifers fed a single exposure to different substrates (Chapter 4) and also among lactating cows fed different feeding strategies at different supplementary feeding amounts (Chapter 5) and these communities were associated with rumen fermentation characteristics. Cattle appeared to have host specific rumen bacteria and a core microbiome (Chapters 4 and 5). This suggests that host specificity in rumen ecosystems may be associated with the individual susceptibilities of cattle to ruminal acidosis and a need to tailor feed management and control for ruminal acidosis for individual cattle. Supplementary feeding amount and ruminal concentrations of propionate and valerate appeared to have the largest association with ruminal bacterial communities in Chapter 5 and may be good predictors of ruminal acidosis. A partial mixed ration feeding system, compared with component feeding, decreased ruminal acidosis (Chapter 5), suggesting benefits of this feeding system; however, milk production and milk component benefits were not observed for this feeding system. Feed additive control agents perturbed the rumen by different mechanisms but had minimal synergistic effects when combinations of feed additives were fed and ruminal acidosis control was equivocal (Chapters 6 and 7). Feed additives may not be capable of controlling ruminal acidosis in all cattle when large amounts of readily fermentable carbohydrates are fed (Chapter 7). Concentrations of the volatile fatty acids (VFA): butyrate, propionate, valerate, isobutyrate, isovalerate, and caproate were below detectable limits in a heifer with acute clinical ruminal acidosis 24 h after she consumed a ration with 19.1% sugar and 54.1% starch on a DM basis and her acetate concentration was <20 mM. However, concentrations of these VFA were higher 55 h after she consumed the ration. These findings demonstrate that the rumen is extremely dynamic and can rapidly recover from severe perturbation. Throughout this thesis it has been evident that classic models of ruminal acidosis may not be sufficient to describe the pathogenesis of ruminal acidosis when diets with a high sugar content are fed and uncharacterized rumen bacteria may be involved in the pathogenesis of ruminal acidosis. Definitions of ruminal acidosis to describe acidosis when cattle are fed different substrates, in particular diets with a high sugar content are required. The rumen appears to be better adapted to respond to changes in starch intakes, compared with sugar intakes and cattle have individual rumen responses and susceptibilities to ruminal acidosis during shifts in feed substrates. In summary, this thesis has increased our understandings of the pathogenesis of ruminal acidosis and control strategies for ruminal acidosis in cattle

Increased understandings of ruminal acidosis in dairy cattle

ABSTRACT Ruminal acidosis remains an important and prevalent disorder of economic and welfare concern to the dairy industry worldwide. There are inconsistencies in the diagnostic techniques and definitions of ruminal acidosis and a requirement for further information on the pathogenesis of ruminal acidosis, in particular in regard to the role of feed substrates, such as starch, sugar, and protein (Chapter 1). A greater understanding of changes to the microbiome during ruminal acidosis, feed management, and the possible synergistic effects of feed additive control agents is also required (Chapter 1). Consequently, the overall hypothesis of this thesis, which was supported, is that starch-, sugar-, and protein- or amino acid-based feed substrates would produce different ruminal and blood measures and distinct rumen bacterial community composition associated with different risks of ruminal acidosis. Secondly, that partial mixed ration feeding strategies and feed additive control agents would promote favorable ruminal conditions and reduce the risk of ruminal acidosis, which was also supported; however, whether feed additive control agents reduced the risk of ruminal acidosis was equivocal. Heifers exposed to a single feeding of grain and fructose had an increased risk of ruminal acidosis and accumulated ruminal lactate, compared to those fed grain only (Chapter 2). This highlights that diets with high sugar content should be fed with caution and increase the risk of ruminal acidosis when physically effective fiber is inadequate. Different oxidative stress responses were not observed among treatment groups of heifers fed single exposures of different substrates (Chapter 3) or different feed additives over a 20 d period (Chapter 7), but were evident in a heifer with acute clinical ruminal acidosis (Chapter 8). This suggests oxidative stress responses may only occur during acute clinical ruminal acidosis. Distinct ruminal bacterial community composition occurred among heifers fed a single exposure to different substrates (Chapter 4) and also among lactating cows fed different feeding strategies at different supplementary feeding amounts (Chapter 5) and these communities were associated with rumen fermentation characteristics. Cattle appeared to have host specific rumen bacteria and a core microbiome (Chapters 4 and 5). This suggests that host specificity in rumen ecosystems may be associated with the individual susceptibilities of cattle to ruminal acidosis and a need to tailor feed management and control for ruminal acidosis for individual cattle. Supplementary feeding amount and ruminal concentrations of propionate and valerate appeared to have the largest association with ruminal bacterial communities in Chapter 5 and may be good predictors of ruminal acidosis. A partial mixed ration feeding system, compared with component feeding, decreased ruminal acidosis (Chapter 5), suggesting benefits of this feeding system; however, milk production and milk component benefits were not observed for this feeding system. Feed additive control agents perturbed the rumen by different mechanisms but had minimal synergistic effects when combinations of feed additives were fed and ruminal acidosis control was equivocal (Chapters 6 and 7). Feed additives may not be capable of controlling ruminal acidosis in all cattle when large amounts of readily fermentable carbohydrates are fed (Chapter 7). Concentrations of the volatile fatty acids (VFA): butyrate, propionate, valerate, isobutyrate, isovalerate, and caproate were below detectable limits in a heifer with acute clinical ruminal acidosis 24 h after she consumed a ration with 19.1% sugar and 54.1% starch on a DM basis and her acetate concentration was <20 mM. However, concentrations of these VFA were higher 55 h after she consumed the ration. These findings demonstrate that the rumen is extremely dynamic and can rapidly recover from severe perturbation. Throughout this thesis it has been evident that classic models of ruminal acidosis may not be sufficient to describe the pathogenesis of ruminal acidosis when diets with a high sugar content are fed and uncharacterized rumen bacteria may be involved in the pathogenesis of ruminal acidosis. Definitions of ruminal acidosis to describe acidosis when cattle are fed different substrates, in particular diets with a high sugar content are required. The rumen appears to be better adapted to respond to changes in starch intakes, compared with sugar intakes and cattle have individual rumen responses and susceptibilities to ruminal acidosis during shifts in feed substrates. In summary, this thesis has increased our understandings of the pathogenesis of ruminal acidosis and control strategies for ruminal acidosis in cattle

Ruminal bacterial communities differ in early-lactation dairy cows with differing risk of ruminal acidosis

IntroductionEarly-lactation Holstein cows (n= 261) from 32 herds in three regions (Australia, California, and Canada) were previously categorized using a discriminant analysis model as being at a high (26.1% of cows), medium (26.8% of cows), or low risk (47.1% of cows) of ruminal acidosis. We aimed to investigate if (1) risk of acidosis would be associated with ruminal bacterial taxa and dietary nutrient components, (2) there would be individual or combinations of bacterial taxa associated with acidosis-risk groups, and (3) the abundance of bacterial taxa would be associated with the intake of dietary nutrient components.MethodsDiets ranged from pasture supplemented with concentrates to total mixed rations. Bacteria 16S ribosomal DNA sequences from rumen samples collected &lt; 3 hours after feeding via stomach tube were analyzed to determine bacterial presence. The relative abundance of each bacterial phylum and family was center log transformed and the transformed family data were subjected to two redundancy analysis biplots, one for acidosis risk group and one for region, to identify the 20 best-fit bacterial families from each respective redundancy analysis. A total of 29 unique families were identified when the lists of 20 families were combined from each redundancy analysis, and these 29 families were termed "influential" families." The association of acidosis-risk groups with the abundance of individual influential families was assessed by mixed models. Backward stepwise elimination mixed models were used to determine the bacterial taxa associated with each acidosis-risk group and the dietary nutrients associated with the abundance of the bacterial taxa.Results and discussionHigh-risk acidosis cows were associated with increased abundances of Anaerocella_f and Veillonellaceae and decreased abundances of several bacterial families with different characteristics. Five phyla: Firmicutes [odds ratio (OR) = 7.47 ± 7.43], Spirochaetes (OR = 1.28 ± 0.14), Lentisphaerae (OR = 0.70 ± 0.07), Planctomycetes (OR = 0.70 ± 0.09), and Tenericutes (OR = 0.44 ± 0.15), and nine families were associated with a higher risk of acidosis. Of the nine phyla identified to be of interest based on abundance and strength of association with acidosis-risk groups, all had one or more dietary nutrient that predicted their abundance. Sugar was the most frequently associated nutrient with the nine phyla, and was present in 78% (seven out of nine phyla) of the models; crude protein was present in 56% of models and crude fat was present in 44% of the models. Sugar and crude protein were most associated with the influential families and all but three families had one or more nutrient predictive of their abundance. Ruminal bacterial taxa are associated with ruminal acidosis; dietary sugar and crude protein are vital predictors of these and, thus, of ruminal acidosis risk

Cardiovascular health promotion : A systematic review involving effectiveness of faith-based institutions in facilitating maintenance of normal blood pressure

Globally, faith institutions have a range of beneficial social utility, but a lack of understanding remains regarding their role in cardiovascular health promotion, particularly for hypertension. Our objective was assessment of modalities, mechanisms and effectiveness of hypertension health promotion and education delivered through faith institutions. A result-based convergent mixed methods review was conducted with 24 databases including MEDLINE, Embase and grey literature sources searched on 30 March 2021, results independently screened by three researchers, and data extracted based on behaviour change theories. Quality assessment tools were selected by study design, from Cochrane risk of bias, ROBINS I and E, and The Joanna Briggs Institute's Qualitative Assessment and Review Instrument tools. Twenty-four publications contributed data. Faith institution roles include cardiovascular health/disease teaching with direct lifestyle linking, and teaching/ encouragement of personal psychological control. Also included were facilitation of: exercise/physical activity as part of normal lifestyle, nutrition change for cardiovascular health, cardiovascular health measurements, and opportunistic blood pressure checks. These demand relationships of trust with local leadership, contextualisation to local sociocultural realities, volitional participation but prior consent by faith / community leaders. Limited evidence for effectiveness: significant mean SBP reduction of 2.98 mmHg (95%CI -4.39 to -1.57), non-significant mean DBP increase of 0.14 mmHg (95%CI -2.74 to +3.01) three months after interventions; and significant mean SBP reduction of 0.65 mmHg (95%CI -0.91 to -0.39), non-significant mean DBP reduction of 0.53 mmHg (95%CI -1.86 to 0.80) twelve months after interventions. Body weight, waist circumference and multiple outcomes beneficially reduced for cardiovascular health: significant mean weight reduction 0.83kg (95% CI -1.19 to -0.46), and non-significant mean waist circumference reduction 1.48cm (95% CI -3.96 to +1.00). In addressing the global hypertension epidemic the cardiovascular health promotion roles of faith institutions probably hold unrealised potential. Deliberate cultural awareness, intervention contextualisation, immersive involvement of faith leaders and alignment with religious practice characterise their deployment as healthcare assets

Increasing Feed Conversion Efficiency in Automatic Milking Systems: The Impact of Grain-Based Concentrate Allocation and Kikuyu (\u3cem\u3ePennisetum clandestinum\u3c/em\u3e) Pasture State on Kikuyu Pasture Digestibility

Automatic milking system (AMS) farms, rely upon voluntary cow traffic (the voluntary movement of cattle around a farm) for milk harvesting and feed consumption. Dairy cows on a pasture-based AMS farm typically move from depleted to fresh allocations of pasture in small groups, or individually, at differing times. The first cows moving to an allocation of fresh pasture get access to rapidly fermentable, ad libitum, high quality pasture in contrast to those cows accessing the same allocation towards the end of the access period. At the same time, grain-based concentrate (GBC) is allocated independent of the pasture state that cows access. Inclusion of a high level of GBC in the diet with high or low nutritive value forage, or variable states of forage, may create dramatic variations in rumen fluid pH, which may induce subacute ruminal acidosis (Bramley 2004), reduce feed conversion efficiency and negatively impact animal health. The aim of the current study was to determine the impact of pasture state and GBC allocation on the digestibility of kikuyu pasture

Increasing Feed Conversion Efficiency in Automatic Milking Systems: The Impact of Grain-Based Concentrate Allocation and Kikuyu (\u3cem\u3ePennisetum clandestinum\u3c/em\u3e) Pasture State on Milk Production

Pasture is typically offered to dairy cows in three allocations in pasture-based automatic milking systems (AMS). However, due to voluntary cow movement and distribution of milkings, some dairy cows access fresh pasture and other cows access depleted (stale) pasture. The first cows moving to an allocation of fresh pasture are offered ad-libitum, high quality pasture as opposed to cows arriving to the same allocation during the middle or end of the day accessing poorer quality, high fibre (neutral detergent fibre, NDF) pasture. In addition, grain-based concentrate (GBC) is allocated independently to this pasture state. The ability to increase feed conversion efficiency and AMS herd milk production by targetedGBC supplementation to cows accessing differing pasture states is unknown. Therefore, the aim of the current experiment was to determine the impact of pasture state and GBC allocation on dairy cow milk production

Occupational therapy consensus recommendations for functional neurological disorder

BACKGROUND: People with functional neurological disorder (FND) are commonly seen by occupational therapists; however, there are limited descriptions in the literature about the type of interventions that are likely to be helpful. This document aims to address this issue by providing consensus recommendations for occupational therapy assessment and intervention. METHODS: The recommendations were developed in four stages. Stage 1: an invitation was sent to occupational therapists with expertise in FND in different countries to complete two surveys exploring their opinions regarding best practice for assessment and interventions for FND. Stage 2: a face-to-face meeting of multidisciplinary clinical experts in FND discussed and debated the data from stage 1, aiming to achieve consensus on each issue. Stage 3: recommendations based on the meeting were drafted. Stage 4: successive drafts of recommendations were circulated among the multidisciplinary group until consensus was achieved. RESULTS: We recommend that occupational therapy treatment for FND is based on a biopsychosocial aetiological framework. Education, rehabilitation within functional activity and the use of taught self-management strategies are central to occupational therapy intervention for FND. Several aspects of occupational therapy for FND are distinct from therapy for other neurological conditions. Examples to illustrate the recommendations are included within this document. CONCLUSIONS: Occupational therapists have an integral role in the multidisciplinary management of people with FND. This document forms a starting point for research aiming to develop evidence-based occupational therapy interventions for people with FND

Assessment of Public-Private Partnership (PPP) Models in Health Systems in Least Developed, Low Income and Lower-Middle-Income Countries and Territories : A Protocol for a Systematic Review.

Background: Private sectors play a significant role in health provision along with the public sector in both developed and developing countries. Given the limited resources of the public sector, Public-Private Partnerships (PPPs) are considered as a good solution to address the growing public health challenges. But inadequate assessment of various health-related PPPs has resulted in a failure to gather knowledge and evidence that would facilitate the establishment of effective partnerships, sustain, and systematize them over time, as well as determine the role of PPPs in health system strengthening, particularly in terms of urban health provision. The objective of this research is to systematically review the effectiveness of PPPs on the utilization of urban health provision to achieve health outcomes in the urban contexts of least developed, low income, and lower-middle-income countries and territories.Methods: This systematic review will follow PRISMA-P guidelines for reporting. Relevant databases-EMBASE, MEDLINE, Health Management Information Consortium, Social Sciences Citation Index, Science Citation Index, Emerging Sources, CENTRAL, i.e., Database of disability and inclusion information resources, and WHO Library Database–will be searched for published articles in the urban context. Reference lists of relevant systematic reviews and commentaries and citations of key included studies will be checked for additional studies. Two reviewers will independently screen the studies in covidence following the exclusion and inclusion criteria. Data will be thematically analysed and narratively synthesized.Discussion: This review will comprehensively assess and appraise all the existing PPP models for urban health provision in the least developed, low income, and lower-middle-income countries and territories. The findings of the review will help to understand the modalities of the existing health related PPPs in urban areas, their functionalities, and their contribution in achieving health outcomes.Protocol registration: This protocol is registered with the International Prospective Register of Systematic Reviews, PROSPERO (ID-CRD42021289509, 23 November 2021)