Search

Abstract: Accurately measuring and monitoring of animal behavior is an important factor when assessing on-farm animal welfare. First we developed a feasible and simple method aiming at consistently on-farm measuring of pig''s behavior. This test should cover a broad range of welfare-related pig behavior. The reaction towards a novel object, startling, tail and ear biting, play and aggressive behavior, stereotypies, coughing, sneezing, skin lesions, defecation, urination and cleanliness of body and pen are included. The development of accurate measures of on-farm behavior first requires the reliability assessment of the procedure. Therefore, the methodology was tested in a first part by three observers scoring simultaneously and independently pre-defined behavioral characteristics of 108 group-housed fattening pigs. The inter-observer repeatability of the measures was calculated using intraclass correlation coefficients, which ranged from 0.7 to 1. In a second part, the objective was to validate the behavioral characteristics against salivary cortisol, urinary epinephrine and norepinephrine and production traits. Salivary cortisol concentrations significantly increased in ear-bitten pigs and in pigs with tail lesions. Growth rate significantly dropped when cortisol levels rose. An age effect was also found. The percentage of animals approaching the novel object is positively correlated with the urinary epinephrine concentration. Pigs defecating during the test showed significantly higher epinephrine levels. Urinary norepinephrine concentration decreased significantly with age. Faster growing animals and animals with tail lesions showed significantly higher levels of norepinephrine. Pen dirtiness and number of animals per pen were associated with higher norepinephrine concentrations. Finally, barrows had higher norepinephrine concentrations than sows. [Copyright &y& Elsevier]

Many approaches are available for the analysis of continuous longitudinal data. Over the last couple of decades, a lot of emphasis has been put on the linear mixed model. The current paper is dedicated to an overview of this approach, with emphasis on model formulation, interpretation and inference. Advantages as well as drawbacks are discussed, and guidelines are given for general statistical practice. Special attention is given to the problem of missing data, i.e., the case where not all data are present as planned in the original design of the study. [ABSTRACT FROM AUTHOR]

The concept of negative variance components in linear mixed-effects models, while confusing at first sight, has received considerable attention in the literature, for well over half a century, following the early work of Chernoff [7] and Nelder [21]. Broadly, negative variance components in linear mixed models are allowable if inferences are restricted to the implied marginal model. When a hierarchical view-point is adopted, in the sense that outcomes are specified conditionally upon random effects, the variance–covariance matrix of the random effects must be positive-definite (positive-semi-definite is also possible, but raises issues of degenerate distributions). Many contemporary software packages allow for this distinction. Less work has been done for generalized linear mixed models. Here, we study such models, with extension to allow for overdispersion, for non-negative outcomes (counts). Using a study of trichomes counts on tomato plants, it is illustrated how such negative variance components play a natural role in modeling both the correlation between repeated measures on the same experimental unit and over- or underdispersion. [ABSTRACT FROM AUTHOR]

Convergence problems often arise when complex linear mixed-effects models are fitted. Previous simulation studies (see, e.g. [Buyse M, Molenberghs G, Burzykowski T, Renard D, Geys H. The validation of surrogate endpoints in meta-analyses of randomized experiments. Biostatistics. 2000;1:49–67, Renard D, Geys H, Molenberghs G, Burzykowski T, Buyse M. Validation of surrogate endpoints in multiple randomized clinical trials with discrete outcomes. Biom J. 2002;44:921–935]) have shown that model convergence rates were higher (i) when the number of available clusters in the data increased, and (ii) when the size of the between-cluster variability increased (relative to the size of the residual variability). The aim of the present simulation study is to further extend these findings by examining the effect of an additional factor that is hypothesized to affect model convergence, i.e. imbalance in cluster size. The results showed that divergence rates were substantially higher for data sets with unbalanced cluster sizes – in particular when the model at hand had a complex hierarchical structure. Furthermore, the use of multiple imputation to restore ‘balance’ in unbalanced data sets reduces model convergence problems. [ABSTRACT FROM PUBLISHER]

Concerns in regard to thermal discomfort experienced by cattle are increasing, especially in the summer time. It is important to determine whether or not pastured beef cattle would make use of shade during sunny circumstances in a temperate climate. If so, scientifically based guidelines may need to be formulated for translation into legislation aiming to protect animal welfare. Approximately 255 beef cattle on 18 pastures were observed from July 2010 through November 2010 in central Belgium. Pastures having either natural or artificial shelter for animal protection but similar with respect to agricultural and climatological characteristics were included in the study. The analysis of data focused on the effect of weather conditions on sheltering behavior of cattle, with pasture as a random factor. During sunny weather, ambient temperature had a significant influence on the use of shade (P < 0.0001): the greater the environmental temperature was, the more cattle on a pasture were located in a shaded area. Ambient temperature (Ta) and relative humidity (RH) both tended to have a positive relation with shade use. However, the expected impact of their combined effect was not found, probably because of the strong negative correlation between RH and Ta (r = -0.7122) in the studied region. Greater wind speed (WS) reduced the need for shade, even at a greater Ta (P < 0.0001). Both Ta and solar radiation (RAD) influenced use of shade, but the interaction or combined effect was not significant. The variability of shade use between the pastures in this study could be explained by the surface of shade present on the pasture. It is rather self-evident that cows made more use of shade when a greater percentage of the surface area was shaded, but the presence of remaining nonshaded area kept the alternative choice reliable. On the basis of the fact that more cattle being observed in a shaded area was associated with a higher dry air temperature, it can be concluded that providing shelter could also be valuable for pastured cattle living in a temperate region. [ABSTRACT FROM AUTHOR]

Surgical castration of male piglets without anesthesia is a routine management practice conducted on commercial pig farms. For animal welfare reasons, it would be beneficial to develop methods of practical pain relief. The objective of this study was to evaluate the effect of providing CO2 anesthesia before castration on the behavior of piglets for up to 8 d after castration in comparison with piglets castrated without anesthesia. In 3 successive replicates, the behavior of 186 male piglets castrated with (n = 95) or without (n = 91) anesthesia was observed for up to 8 d after castration. All piglets in a given replicate were castrated on the same day, before 8 d of age. Behavioral observations were carried out in accordance with a continuous focal sampling procedure that began immediately after castration and continued for a period of 1 wk. Barrows anesthetized with CO2 before castration displayed more interactive behaviors during the overall observation period than the other barrows (P = 0.0412), which may indicate better welfare. Assessing all observation periods separately, differences in activity at the udder, lying, walking, and interactive behaviors appeared to support the beneficial effect of providing CO2 anesthesia before castration. However, these differences varied over time between treatment groups. The most important conclusion was that piglets castrated with or without CO2 anesthesia displayed behaviors indicative of pain and discomfort for up to 6 d after castration. Therefore, additional analgesia may be necessary to eliminate the long-term pain caused by castration even in piglets anesthetized with CO2 before castration. [ABSTRACT FROM AUTHOR]

The transgenic improvement of a commercial crop requires a suitable transgene as well as a suitable insertion location in the crop’s genome. An elite event is a successful insertion of an active transgene, and many events need to be screened to detect such elite events. This is expensive, hence optimization is needed. The screening of events in a commercial crop is usually preceded by the screening of genes in an easily transformable test plant, either a non-commercial variety of the crop or another species. This first phase mainly aims at discovering active genes. The results from the first phase can also be utilized to predict the probability of finding elite events with similar or larger effects in the commercial crop, making use of estimated variance components in the mixed model framework. The theoretical relationship between these variance components and the probability to discover in the second phase an event with an effect of a predefined magnitude is studied. The consequences of having to estimate the variance components from a first phase experiment are studied through simulations. These show that, in order to be useful to assist in the design of the second phase, the first phase should involve a large number of events, typically more than 30. The number of events is much more important than the number of plants within an event. The approach is applied to real data obtained in a commercial screening facility. [ABSTRACT FROM AUTHOR]

One of the major concerns when analysing incomplete longitudinal data is the fact that models necessarily rest on strong assumptions, unverifiable from the data. In response to these concerns, there is growing awareness of the usefulness of sensitivity analysis. In this paper we will focus on repeated ordinal data. Specifically, we implement a formal approach to such a sensitivity assessment, based on local influence, in the presence of multivariate categorical data. We explore the influence of perturbing a MAR dropout model in the direction of non-random dropout, and apply the proposed method to data from a longitudinal multicentre psychiatric study. [ABSTRACT FROM AUTHOR]

During the last decade, several papers have been published on group sequential methods in general and on sequential longitudinal clinical trials in particular. This paper gives an overview of the proposed methods, emphasizing longitudinal clinical trials. Furthermore, it tries to answer some practical questions that may arise during the conduct of interim analyses in longitudinal trials. Simulations have been carried out to obtain insight in these practical considerations. [ABSTRACT FROM AUTHOR]

Objective. Muscle receptors and selected anabolic effects have been identified for both insulin-like growth factor I (IGF-I) and 1,25-dihydroxyvitamin D (1,25(OH)2D3). The aim of the present study was to test the hypothesis that the decreasing concentrations of these endocrine factors might be involved in the decline in muscle function that characterizes normal human ageing. Design. Cross-sectional study. Study participants. A community-based sample of 245 healthy elderly women aged 70-90 years. Exclusion criteria were diseases or medications known to affect muscle function or the somatotrophic axis. Measurements. Knee extension strength was evaluated using an isokinetic dynamometer. A standardized questionnaire was used to assess habitual physical activity. IGF-I and 1,25(OH)2D3 were measured by radioimmunoassay. Vitamin D binding protein (DBP) was measured by single radial immunodiffusion and the free 1,25(OH)2D3 concentration calculated as the molar ratio of total 1,25(OH)2D3 to DBP. Results. The differences in isometric and isokinetic strength over the age range were equivalent to losses of 0.9-2.4% per year. However, no relationship was found between the somatotrophic axis or vitamin D status and knee extension strength, despite markedly decreasing concentrations of circulating IGF-I and free 1,25(OH)2D3 with age. Conclusion. Levels of circulating IGF-I and free 1,25(OH)2D3 appear not to be involved in the loss of muscle function that characterizes normal human ageing. [ABSTRACT FROM AUTHOR]

Background: The peak of the global COVID-19 pandemic has not yet been reached, and many countries face the prospect of a second wave of infections before effective vaccinations will be available. After an initial phase of viral replication, some patients develop a second illness phase in which the host thrombotic and inflammatory responses seem to drive complications. Severe COVID-19 disease is linked to high mortality, hyperinflammation, and a remarkably high incidence of thrombotic events. We hypothesize a crucial pathophysiological role for the contact pathway of coagulation and the kallikrein-bradykinin pathway. Therefore, drugs that modulate this excessive thromboinflammatory response should be investigated in severe COVID-19.Methods: In this adaptive, open-label multicenter randomized clinical trial, we compare low molecular weight heparins at 50 IU anti-Xa/kg twice daily-or 75 IU anti-Xa twice daily for intensive care (ICU) patients-in combination with aprotinin to standard thromboprophylaxis in hospitalized COVID-19 patients. In the case of hyperinflammation, the interleukin-1 receptor antagonist anakinra will be added on top of the drugs in the interventional arm. In a pilot phase, the effect of the intervention on thrombotic markers (D-dimer) will be assessed. In the full trial, the primary outcome is defined as the effect of the interventional drugs on clinical status as defined by the WHO ordinal scale for clinical improvement.Discussion: In this trial, we target the thromboinflammatory response at multiple levels. We intensify the dose of low molecular weight heparins to reduce thrombotic complications. Aprotinin is a potent kallikrein pathway inhibitor that reduces fibrinolysis, activation of the contact pathway of coagulation, and local inflammatory response. Additionally, aprotinin has shown in vitro inhibitory effects on SARS-CoV-2 cellular entry. Because the excessive thromboinflammatory response is one of the most adverse prognostic factors in COVID-19, we will add anakinra, a recombinant interleukin-1 receptor antagonist, to the regimen in case of severely increased inflammatory parameters. This way, we hope to modulate the systemic response to SARS-CoV-2 and avoid disease progressions with a potentially fatal outcome.Trial Registration: The EU Clinical Trials Register 2020-001739-28 . Registered on April 10, 2020. [ABSTRACT FROM AUTHOR]

Background: Both a decrease in bone formation and the skeletal consequences of secondary hyperparathyroidism have been implied in the pathogenesis of age-related femoral neck osteoporosis. However, studies using biochemical indices of bone remodeling in hip fracture patients have yielded conflicting results. Similarly, secondary hyperparathyroidism has not been a consistent finding in this population. Some of these inconsistencies might reflect differences in the assays used as well as in the timing of the sampling. Moreover, measurements were mostly performed in a limited number of patients. In this regard, the aim of the present study was to analyze potential alterations in bone metabolism in a large population of elderly hip fracture patients.Methods: Circulating concentrations of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)2D3], intact parathyroid hormone (PTH), and calcitonin were measured in 117 elderly women (within a few hours after sustaining a fracture of the proximal femur) and in 117 healthy age-matched controls. In addition, serum osteocalcin and urinary excretion of (deoxy)pyridinoline were determined as markers of bone formation and resorption, respectively.Results: Serum levels of 25(OH)D and 1,25(OH)2D3 were decreased in hip fracture patients. When correcting for differences in serum vitamin D binding protein, serum 25(OH)D was still significantly lower in patients than in controls, whereas serum 1,25(OH)2D3 was not. Moreover, 25(OH)D deficiency in hip fracture patients was associated with an increase in circulating PTH and urinary excretion of (deoxy)pyridinoline. Serum osteocalcin, on the other hand, was significantly decreased in fracture patients. There was no statistically significant difference in calcitonin.Conclusion: These data suggest that there is reduced bone formation and increased bone resorption in patients with hip fracture. Although limited by its cross-sectional design, the present study emphasizes the role of secondary hyperparathyroidism-induced bone resorption in the pathogenesis of age-related osteoporosis, mainly due to a lack of 25(OH)D. [ABSTRACT FROM AUTHOR]

This study investigates the relationship between sound levels, pre-slaughter handling during loading and pork quality. Pre-slaughter variables were investigated from loading till slaughter. A total of 3213 pigs were measured 30 min post-mortem for pH 30LT ( M. Longissimus thoracis ). First, a sound level model for the risk to develop PSE meat was established. The difference in maximum and mean sound level during loading, mean sound level during lairage and mean sound level prior to stunning remained significant within the model. This indicated that sound levels during loading had a significant added value to former sound models. Moreover, this study completed the global classification checklist (Vermeulen et al., 2015a) by developing a linear mixed model for pH 30LT and PSE prevalence, with the difference in maximum and mean sound level measured during loading, the feed withdrawal period and the difference in temperature during loading and lairage. Hence, this study provided new insights over previous research where loading procedures were not included. [ABSTRACT FROM AUTHOR]

Environmental variables, as sound levels, were collected during the pre-slaughter process in 18 different Belgian commercial slaughterhouses. Four pre-slaughter phases were determined: firstly after arrival of the truck at the slaughterhouse and just before unloading, secondly during unloading, thirdly at lairage and finally while moving to the stunner. A total of 8508 pigs was examined during the pre-slaughter process, of which the pH LT ( M. longissimus thoracis ), at 30 min post-mortem was measured. For each pre-slaughter phase, variables which might influence pork quality were determined. Moreover, this study made it possible to infer a checklist to represent and predict PSE traits of pork for all kind of pre-slaughter situations. The checklist shows also that the impact on pork quality is more decisive for the variables measured close to the stunning phase. Hence, this information is useful for the industry to optimize handling of pigs, reducing the risk for PSE traits. [ABSTRACT FROM AUTHOR]

This study investigates whether sound levels above 85 dB(A), determined in literature as a critical sound level to induce stress in pigs, has also an effect on the pH of pork. Sound levels were recorded during pre-slaughter phases. A measure was taken after the arrival of the truck at the slaughterhouse, during unloading, lairage and just before stunning. The pH of the Longissimus thoracis or lumborum , 30 min after sticking (pH 30LT ) was measured. 8508 pigs were examined and the pH was measured on the carcasses. The results show that the cut-off value of 85 dB(A) during the pre-slaughtering phase is not only a threshold to evaluate animal welfare but can also be associated with a slower drop of pH if sound levels are < 85 dB(A). Finally a linear mixed model for pH 30LT was built with the sound level during lairage and the sound level prior to stunning as independent variables, having statistically the highest impact on pH 30LT of pork. [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via the original article. [ABSTRACT FROM AUTHOR]

Purpose: Evidence on risk factors for sick leave from prospective studies in work settings is limited. Furthermore, most available studies focused on workers with substantial low back disorders. These studies consistently report that physical work factors constitute a hindrance to work. However, it remains unclear whether the same risk factors are relevant in workers with less severe conditions or in early phases of the development of back pain. Therefore, this article aims to study risk factors for the occurrence of sick leave due to low back pain (LBP) among young workers with no or a modest history of back pain. Methods: Participants were 716 young healthcare or distribution workers with no or minimal antecedents of LBP in the year before inclusion. We investigated the role of potential physical, psychosocial and individual risk factors at baseline on the occurrence of sick leave due to LBP 1 year later. To this purpose, we used Cox regression with a constant risk period. Results: Six per cent (95 % CI 4.1-7.6) of the workers reported sick leave 1 year later; they accounted for 12 % of the sick-leave days independent of cause. A non-stimulating psychosocial work environment turned out to be the strongest risk factor for sick leave due to LBP (RR 6.08; 95 % CI 1.42-26.07). Physical factors were not predictive. Conclusions: In the early phases of back pain and in less severe conditions, the main benefit of interventions lies in targeting the organisation and design of jobs to create a challenging professional environment. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to evaluate the effect of two treatments with varying dietary total Lys:NE ratios and NE concentrations in a concept of phase feeding from weaning to slaughter on growth performance and final carcass measures of crossbred pigs selected for leanness. All pigs were fed a meal diet according to a 5-phase ad libitum feeding scheme (8–12kg, 12–20kg, 20–40kg, 40–70kg, 70–105kg). During the first phase (8–12kg), all pigs were fed the same commercial starter diet, containing 1.14gLysMJ−1 NE and 9.77MJ NE. Afterwards, the pigs were randomly assigned either to a standard diet or a concentrated diet. The standard diets during the last 4 subsequent phases were characterized by Lys:NE ratios of 1.14, 1.04, 0.97 and 0.91gLysMJ−1 NE and NE concentrations of 9.74, 9.83, 9.83 and 9.76MJ NE. The concentrated diets contained increased levels of Lys:NE, i.e. 1.14, 1.04, 0.97 and 0.91gLysMJ−1 NE and NE concentrations, i.e. 10.02, 10.36, 10.36 and 10.19MJ NE. Overall, no effect of feeding the concentrated diet was found on the growth rate from weaning to slaughter. However, analysing the data for each growing phase reveals that feeding the concentrated diet had a positive effect on daily gain, feed efficiency and energy efficiency from 12 to 20kg and from 20 to 40kg. After 40kg, daily gain was unaffected by treatment, but feed and energy efficiency were positively affected when feeding the standard diet. Finally, lean meat content was unaffected by treatment. In conclusion, accurately tuning nutrient density to pigs' genetic capacity to grow and deposit lean meat is necessary, in order to maximize profitability in relation to feed cost. A negative effect on growth can be observed during the last phases before slaughter which was explained as an effect of oversupply of nutrients. Especially during these phases, feed cost is a deciding factor because of the lower feed efficiency in comparison with the earlier phases. [Copyright &y& Elsevier]

Abstract: A total of 12,725 pigs originating from 90 transports were followed up at 17 Belgian commercial slaughterhouses. The effects of several pre-slaughter parameters concerning transport, unloading, lairage, pig handling, stunning and season on fresh meat quality based on pH measurements 30minutes (min) after slaughter were investigated. Meat quality was measured on 4285 pigs. Ten pre-slaughter parameters had a significant effect on meat pH after separate introduction of the variable as a fixed effect in the model. Simultaneous analysis of these variables in the global model revealed that the pH was influenced by four main risk factors, namely the mean noise level produced during unloading, the percentage of panting pigs, the use of an electric prod and season. Meat quality in terms of the percentage of potentially PSE carcasses was better in summer than spring or autumn and could be explained by a lower observed pre-stunning stress in summer. [ABSTRACT FROM AUTHOR]

Lung lesions of about 1000 pigs (nN) were scored in the slaughter line. Carcass weight, back fat thickness, loin muscle depth, pHi and PQMi were measured on 460 pigs. Twenty-four hours after slaughter pHu, PQMu, brightness, redness, yellowness and drip loss were measured on 59 carcasses. A score for lung lesions was assessed at batch level, based on observations of all pigs in that batch, i.e. about 130. Pigs systematically selected from batches scoring more than 25% lung lesions had a lower pH of LD muscle (P ≤ 0.0003) and a six fold higher risk for P(ale)S(oft)E(xudative) traits (P ≤ 0.050) compared to batches scoring less than 5%. [ABSTRACT FROM AUTHOR]