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As a continuation of our previous work, which concerned the binding of aldehydes to bisulfite and cysteine, this article presents more results on the applicability of 4-vinylpyridine addition to beer prior to analysis aiming at release of aldehydes from these preformed bound states, thus making them quantifiable with the headspace solid-phase microextraction method combined with gas chromatography-mass spectrometry. This article also presents the first results on spiking beer samples with cysteine prior to forced-aging, pointing to the important role of cysteine in beer flavor stability. Both the levels in free and bound aldehydes show a relatively large degree of variation among different beers, but also between marker aldehydes. For some aldehydes (e.g., hexanal), the bound amount was shown to increase rather strongly upon forced beer aging, whereas for others (e.g., 2-methylpropanal), large amounts appeared to already be present in a bound state in the fresh samples. Spiking beer samples with cysteine prior to aging significantly lowered the aldehyde levels compared with nonspiked samples. Flavor stability of the cysteine-spiked beers was thereby greatly improved through aldehyde-cysteine adduct formation. It was further hypothesized that, in addition to efficient binding of aldehydes, cysteine also inhibits the formation of furfural during beer aging from Maillard reaction intermediates.

The potential involvement of 2-substituted 1,3-thiazolidine-4-carboxylic acids in beer flavor stability was further investigated. The binding behavior of beer-aging aldehydes toward both cysteine a...

Increases in the levels of staling aldehydes during beer aging are likely to involve bound aldehydes, already present in fresh beer. In particular, bisulfite adducts and imines have been reported a...

Lameness in sows is an important welfare concern as well as a cause of considerable economic loss. In general, lameness in sows is evaluated by visual scoring of the gait. However, visual assessment is a subjective technique with low reproducibility. Therefore, the need arises for more accurate and objective methods to enable correct detection. A detection system, based on force stance variables derived from force plate analysis and visual stance variables derived from image processing was developed: SowSIS (sow stance information system). The transportable device and computer software was tested in a practical environment and was positively evaluated for its practical use and precise measurements. A preliminary study of the force stance variables was performed by comparing measurements of sound sows and sows with lameness in their hind leg. All lame sows were reluctant to bear weight on their lame leg which resulted in a lower weight exerted by the lame hind leg compared to the other legs. This shift in weight was mainly compensated by putting more weight on the contralateral sound hind leg. Sows showed more but shorter kicks ( i.e. lifting leg of the ground) with their lame leg compared to the other legs. The results indicated that the developed system SowSIS has very promising potential to support future objective research in lameness in sows.

Although many studies have examined the relation between a wide range of factors and quarter milk somatic cell count (qSCC), including physical characteristics of the teat and changes in teat tissue due to milking, the effect of short-term, milking-induced changes in teat dimensions on somatic cell count has not yet been investigated. To identify teat dimensions and milking-induced changes in teat dimensions associated with qSCC, we conducted a longitudinal study (n herds =6, n cows =72, n measurements =12). Parity, stage of lactation, teat barrel diameter, and changes in teat barrel diameter during milking were identified as factors associated with qSCC. Teats with wider barrels had higher qSCC. Negative changes in the diameter of the teat barrel during milking (i.e., thinner teats postmilking compared with premilking) were associated with lower qSCC, whereas positive changes (i.e., thicker teats postmilking compared with premilking) were associated with higher qSCC. Selection toward more optimal teat characteristics may therefore result in improved milk quality and udder health. However, a threshold might exist for the maximum reduction in teat barrel diameter below which udder health is negatively influenced. If so, changes in teat barrel diameter might serve as an indicator for suboptimal milking and incorrect choice of teatcup liner or milking machine settings and thus help improve management of the herd.

Studies on social spacing usually analyse spatial distribution using a single distribution index, and compare this with expected values assuming random spacing. However, different distribution indices give information on different aspects of spatial distribution. Furthermore, when animals use some parts of the study area more often because of environmental factors, assumptions of random spacing do not apply. As a contribution to the development of spatial distribution analysis methodology, we compared three distribution indices: nearest-neighbour distances (NND), coefficient of variation of interindividual distances and coefficient of variation of Dirichlet polygon areas. Distribution was studied at different animal densities, in the presence or absence of a wooden structure. Rabbits, Oryctolagus cuniculus, were chosen as the model species because of their apparent plasticity of spatial behaviour. The observed distribution was compared with a random distribution and with a resource-corrected random distribution that accounted for environmental influences on spacing. Comparisons with these two distributions led to different conclusions. This emphasizes the limited usefulness of comparisons with the random distribution, especially in more heterogeneous environments. However, divergence from random spacing could potentially be used to assess the relative importance of resources. Especially for 6-week-old rabbits, the density at which no evidence of avoidance was found differed between the distribution indices. This underlines the need to use multiple indices when studying social spacing. Nine-week-old rabbits generally avoided each other’s proximity, with NND indicating proximity avoidance even in the largest pens. Contrary to expectations, the wooden structure seemed to decrease social attraction between rabbits.

Interaction between the teat and the teatcup liner can strongly affect the milking characteristics and udder health of dairy cows. Therefore, teat morphology is an important parameter in choosing the most appropriate liner. Nevertheless, information on teat morphology is scarce and rarely sufficient for liner selection. Current techniques for measuring teat morphology are subjective, not always accurate and time consuming, and gathering such information on large scale is difficult. This study presents a new vision based measuring technique that uses a camera to obtain a 2D image of the teat and image processing analysis to determine teat length and diameters. The technique was shown to be accurate. Errors were generally limited to 5% for both teat length and diameters and were less than 2% when the angle of the teat in the longitudinal direction was small.

Cattle lameness causes considerable animal welfare problems and negatively affects the farm economy. Gait scoring techniques and claw health reports are commonly used for research and surveys, but few daily management solutions exist to monitor gait parameters from individual cows within a herd. A tool to automate and process the measurement of spatiotemporal kinematic and force variables was developed using a pressure sensitive walkway, commercial farm infrastructure and management tools. A fully automatic setup on ILVO’s experimental farm measures and analyses the gait of each cow that exits the milking parlour by registration of 20 basic kinematic gait variables. Based on this variable set, a wide range of typical gait parameters such as triple support time, abduction, etc. can be calculated. This paper presents some practical results and considerations related to this system of automated gait analysis. A first validation of the acquired variables shows that the Gaitwise system is capable of clustering observations in relation to the observer score with an overall sensitivity of 76–90% and specificity of 86–100%. Variables of asymmetry and speed seem most promising for further research on the detection of lameness. For future reference, the resulting cow gait variables will be stored for time series analysis to detect changes in individual cow walking behaviour in relation to any source (claw lesions, gestation stage, etc.). Such measurements could provide valuable information for management, veterinary check-ups and further research for automatic lameness detection in cattle.

The appropriate stocking density for broiler chickens is a much discussed topic in animal welfare. To determine at which stocking density the level of crowding becomes aversive to 4–6-week-old broiler chickens, spatial distribution and behaviour of groups stocked at 8, 19, 29, 40, 45, 51, 61 or 72birds per 3.3m 2 were analysed. Spatial distribution was evaluated using three different indices: inter-individual distances, nearest neighbour distances and Dirichlet polygon areas. The assumption was that broilers would increase the distance to their pen mates if high densities (i.e., close proximity to pen mates) were experienced as aversive, whereas they would decrease this distance if close proximity was experienced positively. Increased distances to pen mates would lead to increased nearest neighbour distances and a more homogeneous distribution (i.e., lower variation of inter-individual distances and of Dirichlet-polygon size) than expected by chance. The distribution expected by chance was determined from both a random distribution and a ‘resource-corrected' random distribution (which incorporated environmental influences on spatial distribution but excluded social ones). Behavioural observations showed that at higher stocking densities more sitting bouts ( P =0.003) and adjustments of the sitting and lying posture ( P P =0.001). Birds that were eating/drinking were further apart from their nearest neighbour than birds that were foraging, preening, adjusting their sitting or lying posture or showing "other" behaviour. The results from all three methods of spatial analysis suggested that broilers in groups ≥19birds per 3.3m 2 (ultimately equivalent to 15kg/m 2 ) started to experience the proximity of conspecifics as aversive at some point during the last 3 weeks of rearing. However, nearest neighbour distance analysis showed evidence of aversiveness earlier in life than the other methods of analyzing spatial distribution (variation in inter-individual distance and polygon size), suggesting that nearest neighbour distance is the more sensitive indicator of space requirements. When uneven use of the different areas within the pen was reflected in the expected distribution (i.e., for comparisons to the resource-corrected random distribution) different results were obtained than when such measures were omitted (i.e., for comparisons to the random distribution). As such, this study emphasises the importance of accounting for environmental influences on distribution within a pen.

Broiler chickens are reported to be close to walls at higher densities. The reason for this is not clear, since evolutionary theories would suggest that birds should attempt to be in the middle of the flock. We studied the spatial distribution (during weeks 4–6) of broiler chickens stocked at 2.4, 5.8, 8.8, 12.1, 13.6, 15.5, 18.5 and 21.8 birds/m2 (in 3.3 m2 pens), to investigate the underlying reasons for the pattern of spatial distribution. Three possible reasons were considered: seeking cover from predators in the centre of the flock, seeking cover from predators near walls, and avoidance of disturbances by conspecifics. Spatial distribution was analysed by comparing the number of birds in four separate parts of the pen (inner, inner middle, outer middle and outer). Apart from effects on spatial distribution, birds were predicted to have their behaviour disturbed more often by other birds in the flock as the overall density in the pen increased, leading to shortened bouts of behaviour and an increase in adjustments of the sitting or lying posture. We found that higher treatment density led to shorter sitting and preening bouts (P = 0.024 and P = 0.013), and a sharper decrease in walking bout length as weeks progressed (density × week, P = 0.025). In addition, birds adjusted their sitting or lying posture more often at higher densities (P

The chemistry of beer flavor instability remains shrouded in mystery, despite decades of extensive research. It is, however, certain that aldehydes play a crucial role because their concentration increase coincides with the appearance and intensity of “aged flavors”. Several pathways give rise to a variety of key flavor-active aldehydes during beer production, but it remains unclear as to what extent they develop after bottling. There are indications that aldehydes, formed during beer production, are bound to other compounds, obscuring them from instrumental and sensory detection. Because freshly bottled beer is not in chemical equilibrium, these bound aldehydes might be released over time, causing stale flavor. This review discusses beer aging and the role of aldehydes, focusing on both sensory and chemical aspects. Several aldehyde formation pathways are taken into account, as well as aldehyde binding in and release from imine and bisulfite adducts.

Traditionally, all cows within a herd are milked with the same teat cup liner, although it is hypothesized that considerable variation in teat dimensions exists between cows and quarters within cows. To study at which level (herd, cow, or quarter) most variation in teat dimensions resides, and to identify factors explaining (part of) this variation, both a cross-sectional (n = 2,715) and a longitudinal study (n = 8,678) were conducted. Using an objective and easy-to-use measuring device, teat length and teat diameters were determined In both studies, most variation in teat dimensions was present at the cow or within-cow level, and not at the herd level, indicating that choosing a teat cup liner that is identical for all cows in a herd is far from optimal. Quarter position (front versus hind), parity and lactation stage were identified as factors associated with teat length and teat diameters. Generally, front teats were longer and broader than hind teats. Teat length and diameters increased with parity, although the increase in teat length was not significant from second parity onwards in front teats, based on observations from the longitudinal study. After the first 30 d in milk, teat length substantially and significantly increased, whereas teat diameters decreased. We conclude that better results in teat condition, and eventually in udder health, might be yielded when different teat cup liners are chosen for front versus hind teats or for cows of different parity or lactation stage, with special attention to the first 30 d in milk. However, the biological relevance of these differences should be examined first.

Observers were given brief presentations of pairs of simultaneous stimuli consisting of a visual and a spoken letter. In the visual focused-attention condition, only the visual letter should be reported; in the auditory focused-attention condition, only the spoken letter should be reported; in the divided-attention condition, both letters, as well as their respective modalities, should be reported (forced choice). The proportions of correct reports were nearly the same in the three conditions (no significant dividedattention decrement), and in the divided-attention condition, the probability that the visual letter was correctly reported was independent of whether the auditory letter was correctly reported. However, with a probability much higher than chance, the observers reported hearing the visual stimulus letter or seeing the spoken stimulus letter (modality confusions). The strength of the effect was nearly the same with focused as with divided attention. We also discovered a crossmodal congruity effect: Performance was better when the two letters in a stimulus pair were the same than when they differed in type.