Andreas Flø

Exploring non-invasive methods to assess pain in sheep

The aim of this study was to determine whether changes in eye temperature, measured using infrared thermography (IRT), and heart rate variability (HRV) can detect moderate levels of pain in sheep. Six ewes received the following treatments: 1) noxious ischaemic stimulus by application of a forelimb tourniquet (S), 2) noxious ischaemic stimulus and flunixin meglumine (S+F), and 3) flunixin meglumine (F). Maximum eye temperature, HRV, mechanical nociceptive threshold, blood pressure and behaviour were recorded for up to 60 min, including 15 min of baseline, 30 min during intervention and 15 min post-intervention. There was a tendency towards a decrease in the heart rate variability parameters RMSSD (the root mean square of successive R-R intervals) and SDNN (the standard deviation of all interbeat intervals) in treatment S compared to treatment F, and a significant increase in the same parameters between test day 1 and 3. A reduction in eye temperature was detected for all treatments during intervention, but no difference was found between S and F and S+N and F during intervention. The eye temperature decreased more in test day 2 and 3 compared to test day 1 during intervention. A significant reduction for both lip licking and vocalisation was observed between test day 1 and 3, and forward facing ears was the ear posture most frequently recorded in test day 1. We suggest that HRV is a sensitive, non-invasive method to assess mild to moderate pain in sheep, whereas IRT is a less sensitive method.

Peripheral temperature drop in response to anticipation and consumption of a signaled palatable reward in laying hens (Gallus domesticus).

The present study describes effects of anticipation and consumption of a palatable reward on comb surface temperature. The purpose was to investigate temperature responses as a potential physiological indicator of positive emotional states in laying hens. A rise in body temperature in response to stimuli predictive of or during exposure to unpleasant events has been interpreted as evidence of emotions in mammals and avians. However, this phenomenon has so far only been studied during anticipation of or exposure to negative events; i.e., emotions of a negative valence. Infrared thermography was used to record potential alterations in comb surface temperature to a conditioned cue signaling a reward (mealworms) and during reward delivery. On average, comb temperature dropped 1.5 °C (95% CI: +/-1.2 °C) after exposure to CS and consumption of reward (p~0.0014) when initial comb temperature was above 30 °C. Such temperature drop indicates a peripheral vasoconstriction and has clear resemblances to emotional fever as seen during negative emotional states. Thus, we propose that a drop in peripheral temperature reflects emotional arousal more than emotional valence. Substantial temperature responses due to diet-induced thermogenesis were found, further emphasizing a cautious interpretation of altered comb temperature in studies of animal welfare.

Long-term hygienic barrier efficiency of a compact on-site wastewater treatment system.

The long-term use of a filter-based, on-site wastewater treatment system increases nutrient discharge to receiving waters and may reduce its hygienic barrier efficiency. The main purpose of this research was to assess the hygienic barrier efficiency and the associated health risks of an on-site system that had exceeded its 5-yr design capacity with respect to phosphorus (P) removal. The system was investigated for bacteria and virus removal and assessed with respect to potential health risks in relation to reuse of effluent for irrigation. The system consists of a septic tank, a pressure-dosed vertical flow biofilter, and an up-flow filter unit with lightweight clay aggregates. The total P concentration in the effluent had increased gradually from initially <0.1 mg P L(-1) during the first 2 yr of operation to 1.8 mg P L(-1) after 5.3 yr. Escherichia coli was used as an indicator organism for fecal bacteria removal, whereas bacteriophages phiX174 and Salmonella typhimurium phage 28B (S.t. 28B) were used to model enteric virus removal. An overall decrease in E. coli removal occurred from a complete (approximately 5.6 log10) reduction during the first 3 yr of operation to 2.6 log10 reduction. The removal amounts of the bacteriophages phiX174 and S.t. 28B were 3.9 and 3.7 log10, respectively. Based on removal of S.t. 28B, the risks of rotavirus infection and disease for the investigated scenarios were above the acceptable level of 10(-4) and 10(-3), respectively, as defined by the World Health Organization.

Hot chicks, cold feet

Infrared thermography (IRT) is increasingly applied as a noninvasive technique for measuring surface body temperature alterations related to e.g. stress, emotions and leg pathologies in avian species. As a basis for the validation of IRT as a future tool for veterinary diagnostics such as detection and/or prediction of subclinical footpad pathologies in broiler chickens, this study explored effects of manual restraint at two different ages on footpad temperatures. Head region temperatures were applied as additional measures of emotional arousal and stress. The study demonstrated that footpad temperatures dropped during 10min of restraint (p<0.001, -0.45°C 95% CI (-0.49, -0.41) per min), whilst head region temperatures (e.g. nostril, wattle, eye, and average head temperature) rose (p=0.004, 0.76°C 95% CI (0.39, 1.15) per 10min), which is consistent with body temperature alterations during emotional arousal and stress, termed stress-induces hyperthermia. Temperature differed between 30 and 36 d (p<0.001, 1.71°C 95% CI (1.04, 2.38) per week), but it is impossible to draw conclusions whether this effect was caused by age or by conditioning. Furthermore, sequential sampling order affected temperature (p=0.04, 0.13°C 95% CI (0.01, 0.25)). In conclusion, one needs to take into account the duration of handling and restraint during the assessment of footpad temperatures, as well as the chickens age, previous experience and sequential sampling order, when using IRT technology as a future noninvasive tool to study temperature alterations associated with subclinical footpad pathologies in broiler chickens.

Effects of subclinical footpad dermatitis and emotional arousal on surface foot temperature recorded with infrared thermography in turkey toms (Meleagris gallopavo)

ABSTRACT Footpad dermatitis is a condition that causes lesions on the plantar surface of the footpads in growing turkeys. Potential inflammatory processes and pain associated with increasing severity of footpad dermatitis raise animal welfare concerns. This study investigated whether the temperature of the plantar surface of the foot (the footpads and the entire plantar foot including interdigital membranes) assessed with infrared thermography reflects severity of mild footpad dermatitis as assessed with a Visual Analogue Scale in 80 turkey toms at 10 weeks of age. In order to study effects of a potential emotional arousal due to the testing procedures, effects of sequential testing order and duration of handling of the turkeys was included in the model. Footpad temperatures were significantly lower than foot temperatures (P < 0.001, R2 = 0.57, −3.36°C ± 0.28°C), and higher visual analogue scale scores were anti‐correlated with footpad (−0.06°C ± 0.037°C) and foot temperatures (−0.07°C ± 0.066°C). Furthermore, a negative association between footpad temperature and handling time (−0.02 ± 0.0227, P = 0.048), and a non‐linear association between foot and footpad temperatures and sequential testing order, were found (P<0.001). The results indicate that severity of mild footpad dermatitis as scored visually was associated with the temperatures of the plantar surface of the foot and footpads, and that thermal imaging therefore represents a novel tool for the reliable and non‐invasive early detection of subclinical foot pathologies in turkeys. The association was negative, and the findings therefore indicate that potential inflammatory processes in the epidermis at this early stage of footpad dermatitis are negligible, and/or that the hyperkeratosis of the surface keratin shielded heat emission from the footpads. The associations between surface temperatures, handling time, and sequential testing order suggest an emotional arousal in response to the experimental procedures, and these factors need to be considered when applying infrared thermography in future studies of leg health in turkeys.

Hyperspectral imaging of weathered wood samples in transmission mode

Surfaces are the most vulnerable part of structures due to continuous exposure to variable climatic conditions. Even if weathering mainly affects the aestethic appearance of wooden facades it may lead to more advanced degradation such as wood cracking, checks and consequently penetration of the wood-decaying agents into the material. The goal of this research was to investigate the kinetics of the degradation rate of wooden samples. The experimental specimens were weathered at 15 locations in Europe for a period of 1 month. Hyperspectal imaging was used for evaluation of earlywood and latewood degradation. Two approaches for image analysis were presented highlighting their advantages and constraints regarding the evaluation of weathered samples. The proposed technique was able to scrutinise differences in degradation of earlywood and latewood, therefore provided new understanding for the kinetic of the weathering process.

Hyperspectral near Infrared Imaging of Wooden Surfaces Performed Outdoors and Indoors

Hyperspectral near infrared imaging has been applied in a field study of fungal growth on a variety of wood substrates exposed in an outdoor environment over a six-month period. This study was performed as a follow up to a hyperspectral examination study of fungal growth on wood surfaces in a laboratory setting. Hyperspectral measurements were carried out both outdoors and indoors in order to explore the influence of the different light conditions. Segmentation of the mould growth on the wood surfaces was carried out using principal component analysis, spectral angle mapper and partial least squares-discriminant analysis. Growth curves showing the fungal growth over time were obtained for all the samples from the measurements performed outdoors. However, there are some challenges connected to studies of wood surfaces due to structures caused by growth rings, knots and sometimes cracks. These wood properties will cause a great variation in the spectra from the wood and also cause natural variation in the fungal growth. Determining specific classes in a classification model such as partial least squares-discriminant analysis is proposed as a way to overcome these issues. Moreover, the wood substrates exposed in an outdoor environment will have a colour change due to photodegradation of lignin, wetting/leaching of the upper layer of the wood surface and growth of a variety of wood discolouring fungi. Hyperspectral technology is a promising technique to study wood properties and we plan to carry out a study to be able to separate and model the different effects on colour degradation on wood surfaces.

Spatially and spectrally resolved temperature dependence of defect related luminescence using hyperspectral imaging

Spatially and spectrally resolved defect related photoluminescence of multicrystalline Silicon wafers has been obtained through hyperspectral photoluminescence imaging. The defect related emissions has been studied as a function of temperature, between 300 K (room temperature) and 87 K. The emissions D1, 0.72 eV, VID3 (0.93 eV) and BB (1,1 eV) emissions are detectable at all temperatures and their peak intensities seem to shift to higher energies with decreasing temperatures. A similar shift in the peak energy for the D2 signal is measured, however, the D2 signal is not visible at room temperature and becomes detectable at 127 K. The D3 and D4 transitions do not exhibit a shift in photon energy with temperature.

Static space requirements for creep area as influenced by temperature and piglet resting behavior

Eight litters of 10 pre-weaned piglets were evaluated for resting behavior patterns in a 1x2 m creep box with uniform environment conditions (within 1oC of set point; 0.7 to 2.8oC variation) The space occupied by a litter of 10 piglets at the recommended infrared floor temperatures was AL = 0.29*M 0.53; with AL, area occupied (m2); M, individual piglet mass (kg). Under 4oC too-warm or too-cool conditions the piglets occupied approximately 10% more or less area, respectively. Huddling and fully-sternum (versus fully-recumbent) positions were significantly more common at cool conditions. The area recommended for 10 average-sized piglets at comfortable temperatures at 1-week (3.7 kg), 2-weeks (6.1 kg) and 3-weeks (8.6 kg) of age is 0.58, 0.76, and 0.91 m2, respectively.