Pen Fouling Research Articles

Exploring effects of light intensity on sustainability indicators in finishing pig production

With an ongoing transition towards the use of Light Emitting Diodes, more knowledge is needed on which light settings optimise sustainability parameters in pig production. We studied the effects of four light intensities on social, environmental and economic sustainability indicators, including ammonia emissions, space use, pen fouling, weight gain, carcass quality, perception of the stockkeeper, costs of the light system, and use of drinking water, electricity and medicines. Light treatments included a low (45 lux), medium (198 lux) and high (968 lux) uniform intensity, and a spatial gradient treatment ranging from 71 lux in the front to 330 lux in the back of each pen. The latter treatment aimed to improve the space use of functional areas. A total of 448 growing-finishing pigs were studied on a commercial farm using two consecutive batches of four rooms containing eight pens with seven pigs. Light intensity influenced some aspects of space use and pen fouling. For example, the proportion of pigs lying in the resting area was higher in the high and medium light intensity treatment than in the low intensity and gradient treatment. Moreover, the high-intensity treatment resulted in more fouling with faeces in the feeding area compared with the low-intensity and the gradient treatment. Ammonia emissions were higher in the gradient than in the low intensity treatment (not measured in medium and high intensity treatment). Furthermore, light intensity did not affect weight gain, carcass quality, water use and medicine use. The stockkeeper was content to work in all light conditions, but slightly preferred the medium intensity due to optimal visibility. Concerning economic performance, the costs of the light system and electricity use increased in the following order: low intensity, gradient, medium intensity, and high intensity. In conclusion, contrary to expectation the spatial gradient did not notably improve space use or reduce pen fouling, but rather increased ammonia emissions in comparison with uniform light. This is likely because the gradient could not be applied in an optimal way in the existing housing conditions. Among the other sustainability indicators, mainly electricity use and costs of the light system differed per treatment. These aspects can be improved by further optimising the number of light sources needed per pen to achieve the targeted intensities.

The Effects of Space Allowance and Toy Provision on the Growth, Spatiotemporal Distribution of Behavior, and Pen Cleanliness of Finishing Pigs

Excretion and lying are key behavioral factors that cause pen fouling, thereby affecting pig welfare, pathogen fecal–oral transmission, and air quality in pig housing. This study investigated the effect of space allowance and toy provision on the spatiotemporal distribution of pigs’ excreting and lying behavior, as well as the score of floor cleanliness in finishing pig pens. A total of 144 Landrace × Yorkshire × Duroc hybrid fattening pigs were randomly assigned to 12 part-slatted pens at stocking densities of 0.75, 1.05, and 1.35 m2/pig with 12 pigs per pen, and 2 pens at each density level were provided with hanging chains and rubber stars as toys. The results showed that for the average daily gain (ADG) of the pigs, the main effect of space allowance was significant (p < 0.05). The ADG at the stocking density level of 1.35 m2/pig was significantly higher than 0.75 and 1.05 m2/pig (p < 0.05). The ADG of the pigs at a density of 0.75 m2/pig in the toys group was significantly higher than the no toys group (p < 0.05). When occupied space was limited, the provision of toys was beneficial to the growth performance of the pigs. Space allowance and toy provision did not affect the time-varying regularity of the pigs but had a certain impact on the areas where the two behaviors occurred. At a density of 1.35 m2/pig, the excreting rate in the corner areas of the slatted floor and the lying rate in the middle area of the solid floor were significantly higher than at a density of 0.75 and 1.05 m2/pig (p < 0.05). Under the conditions of this study, when the stocking density was 1.35 m2/pig and toys were provided, the average daily gain of the pigs was the highest, and the pigs excreted more in the defined excretion area, lay more in the lying area, and the cleanliness of the lying area was also higher. In the case of space constraints, the provision of toys can offset some of the adverse effects of space constraints on pig growth and pen cleanliness.

The effect of floor cooling on respiration rate and distribution of pigs in the pen

High indoor temperatures in traditional finisher pig buildings may lead to deteriorating production results, increased pen fouling and increased respiration rate and rectal temperature. Floor cooling may improve the thermal conditions for pigs on solid floors during warm periods, and therefore the objective was to investigate whether floor cooling could lower the respiration rate (RR), increase the percentage of pigs located on the solid floor and reduce fouling.In a commercial finisher pig building in Denmark, ten pens were assigned floor cooling and ten pens served as controls. Water was continuously circulated in embedded pipes in the concrete solid floor and the water was cooled when both the return water from the floor and the outdoor air was warmer than set thresholds. These thresholds were adjusted during the investigation and for outdoor temperature it was either 20 or 18°C, and for return water flow 18, 20 or 22°C.The results showed that floor cooling significantly reduced RR and increased the percentage of pigs located on the solid floor at all three return flow temperatures. E.g. at return flow temperature 20°C, in the temperature interval [28;30.1], floor cooling reduced RR from 98 to 50 bpm (P < 0.0001) and increased the percentage of pigs located on the solid floor from 31.8% to 28.2% (P < 0.001). At return flow temperature 18°C and 20°C, the interaction between pen temperature and cooling was significant, hence floor cooling reduced the effect of the pen temperature. RR increased by 6.6 bpm when the pen temperature increased by 1°C in pens without floor cooling and by 1.9bpm in pens with floor cooling. Floor cooling did, however, not affect pen fouling where more than 25% of the solid floor was soiled in 13% of the observations in both cooled and uncooled pens.

Automatic counting and positioning of slaughter pigs within the pen using a convolutional neural network and video images

Pen fouling is an undesired behaviour of slaughter pigs, which increases labour costs for the farmer, worsens the hygiene and welfare of the pigs, and has negative environmental consequences. Previous research suggests that monitoring the positioning behaviour of grower/finisher pigs within their pen has the potential to be used in early warning systems that can alert the farmer to an impending pen fouling event 1–3 days in advance. For such a warning system to be feasible, monitoring of the pigs’ positioning behaviour must be automated. To this end, we present a novel yet relatively simple method, namely a convolutional neural network (CNN) with a single linear regression output node. The proposed CNN takes partial images of a pen, corresponding to the different areas of the pen, and outputs an estimated count of the number of pigs in the partial image. By inputting three partial images corresponding to the three areas of the pen, the model can estimate the number of pigs in each area. The trained CNN generally performs well when applied to data from unseen test pens, with mean absolute errors of less than 1 pig and coefficients of determination between observed and estimated counts above 0.9. In cases where the trained model underperforms on the test pens, fine-tuning by transfer learning can be applied; we show that an initially underperforming model can be fine-tuned on one day’s worth of test set data (26 labelled images), after which it will produce near-perfect estimates on all subsequent days in the same test set.

Increased air velocity in the lying area improves pen hygiene and reduces ammonia emissions from houses with partly slatted pens for growing/finishing pigs

Partly slatted pens can offer growing/finishing pigs a better house environment than pens with fully slatted floors. Under thermoneutral conditions, pigs prefer to rest on a solid area and some litter can be provided as enrichment. Ammonia emissions are lower in systems with partly slatted pens, provided the pens are kept clean. However, under high-temperature conditions, pigs in partly slatted pens may begin lying on the slatted area and fouling on the solid floor area, resulting in increased ammonia emissions. This study examined the effects of increasing the air velocity (IAV) in the lying area from max 0.5 m s−1 to max 1.0 m s−1 on conditions for pigs in partly slatted pens during warm periods. Air velocity was increased by redirecting the inlet air from the ceiling inlets down into the animal zone.The study was performed in a commercial growing/finishing house with 10 identical rooms, each containing 16 pens for 9-14 pigs growing from 25-30 kg to 115-120 kg live weight. Pigs were introduced simultaneously into two parallel rooms, one with IAV in the lying area and one without (control treatment). During two summers with six batches, concentrations of carbon dioxide (CO2) and ammonia (NH3), pig activity and choice of lying area in the pen, pen fouling and NH3 emissions were recorded in both rooms on four measuring occasions (M1-M4) during the growing period. Gas concentrations were measured by photoacoustic analyser, pig activity and pig choice of lying area by machine vision techniques, and pen fouling by visual inspection. Climate parameters (air temperature, relative humidity) were logged continuously during the growing period. Ammonia emissions were calculated from the ventilation rate (determined by the indirect CO2 tracer gas method) and the difference in ammonia concentration between outlet and inlet air.Under high ambient temperatures, pigs in the IAV treatment were observed lying significantly more often (p<0.05) in the part of the lying area with the highest air velocity. Pigs tended to lie less in the slatted area (p=0.052) in the IAV treatment than in the control. Problems with pen fouling were significantly reduced with increased air velocity in the lying area and NH3 emissions were reduced by 21% (p=0.009), from 8.4 to 6.6 g pig−1 day−1, during the late growing period (M4).In conclusion, increasing air velocity in the lying area of partly slatted pens from max 0.5 to max 1.0 m s−1 influenced pigs´ choice of lying area, improved pen hygiene and reduced ammonia emissions.

Influence of Cooling and Heating Systems on Pen Fouling, Lying Behavior, and Performance of Rearing Piglets

The rearing of piglets is a demanding phase of pig production partly because of the changing temperature requirements of the piglets during rearing. Piglets need high temperatures in the resting area, especially at the beginning, while the optimal temperature is lower toward the end of rearing. To meet the changing temperature demands of the piglets and also to optimize the pen structure, one floor cooling and two heating systems were examined in this study. In two rearing compartments, four pens with 48 piglets each were equipped with a heated cover above a heated/cooled lying area. The lying behavior and performance of 1152 piglets, in addition to the pen fouling, were recorded over six rearing periods. There was no difference between the two heating systems in the lying behavior. However, the acceptance of the lying area was very high in all pens and periods with heating. The cooling had a significant influence on the lying behavior depending on the rearing week. Significantly more piglets lay on the cooled lying area compared with the control pen during the last weeks. The fouling of the pens was not affected by the cooling or heating systems; however, the fouling in all pens was very low. The tested pen structure in combination with a heating and cooling system is a well-functioning way of integrating a solid lying area.

Cooling growing/finishing pigs with showers in the slatted area: Effect on animal occupation area, pen fouling and ammonia emission

Growing and finishing pigs kept in insulated buildings are often exposed to high ambient temperature during summer. In high-temperature conditions, pigs in partly slatted pens change their behaviour to increase lying on the slatted area and fouling on the solid floor area, resulting in increased ammonia emissions. One way to cool the animals is to shower/sprinkle water in the slatted area, allowing pigs to wet their skin to increase heat loss. This study examined the effects of providing showers on pig activity and occupation area in pens, pen fouling and ammonia emission from the room. The investigation was performed in a commercial growing-finishing house with 10 identical rooms, each containing 16 pens for 9–13 pigs growing from 25–30 kg to 115–120 kg. Pigs were introduced into two parallel rooms in the house. During two summers and four batches, one room with showers in the slatted area and one room without per batch were compared in terms of concentrations of carbon dioxide (CO2) and ammonia (NH3), pig activity and occupation area in the pen, pen fouling and NH3 emissions, recorded on four measuring occasions (M1–M4) during the growing period. Gas concentrations were measured using a photoacoustic analyser, pig activity and occupation area detected by machine vision techniques and pen fouling was visually investigated. Climate parameters (air temperature and relative humidity) were logged continuously during the entire growing period. Ammonia emission was calculated from ventilation rate (determined by the indirect CO2 tracer gas method) and the difference in ammonia concentration between outlet and inlet air.The results showed that the pigs spent less time lying on the slats (p < 0.05) and the solid floor was cleaner (p < 0.05) on measuring occasions M2, M3 and M4 in rooms with showers than in control rooms. Mean NH3 emission for the four measurement occasions were 3.0–5.1 g pig−1 day−1 and 4.2–10.0 g pig−1 day−1 for the shower and control rooms, respectively. The differences were significant (p < 0.05) for all measuring occasions. The results also show improved animal environment when using showers to cool pigs at high ambient temperatures.Overall, providing showers in the slatted area in partly slatted pens encouraged growing/finishing pigs to lie in the lying area, reduced problems with pen fouling and decreased NH3 emissions by 45%. The latter could be partly due to reduced pen fouling and partly to dilution of urine on the slatted area and on the surface of slurry in the pit.

Influence of A Cooled, Solid Lying Area on the Pen Fouling and Lying Behavior of Fattening Pigs

Increasing demands on animal welfare and the higher temperatures in summer due to climate change make it necessary to adapt conventional pig husbandry systems. A cooled, solid lying area has the potential to increase lying comfort and reduce the heat stress, which improves animal welfare. In the present study, the effect of a cooled, solid lying area on lying and elimination behavior was investigated. In two fattening compartments, eight pens with 28 pigs each were rebuilt. Two pen designs, different in feeder place and type, were tested. The floor was cooled from 24.5 to 20 °C by cool water in half of the pens. A total of 672 fattening pigs were tested over three fattening periods. The lying behavior was recorded by video analysis three times per week and three times per day. In the pens with a cooled lying area, 14% (SED 2.9; p = 0.002), respectively 12% (SED 0.9; p = 0.0382) more pigs were lying on the solid lying area. Additionally, the fouling of the animals was reduced by the cooling in one pen design; the results were derived from weekly scores (0.42 vs. 0.67; SED 0.058 p = 0.0006). The fouling of the pen was not affected by the floor cooling, however, the fouling in all pens was very low.

Predicting pen fouling in fattening pigs from pig position

Pen fouling is an undesired behaviour of fattening pigs, where they excrete in their designated resting area and rest in their designated excretion area. This causes problems with health due to poor hygiene, and requires laborious efforts for the farmer to clean the pen and correct the behaviour. A review of the existing literature suggests that changes in lying behaviour may precede an event of fouling. Furthermore, observing the lying patterns of fattening pigs in the morning before entering the fattening unit, as a means of assessing the risk of imminent pen fouling, is known to be a common strategy among Danish farmers. In this study, we show that machine learning methods, specifically random forests and artificial neural networks, can be made to predict pen fouling in the days leading up to the event, based on the position of the pigs within the pen at specific times of the day. We could not show any added information value from distinguishing between standing/lying behaviour within a given area of the pen, as opposed to simply knowing the pigs’ position. We found that the most information value, relevant for training a method for predicting fouling events, are located in the last 2–3 days before the event occurs and when the pigs are observed during the morning hours before any disturbance. Lastly, we demonstrate a Bayesian ensemble strategy for combining multiple different prediction models, which yield higher performances than the best performing models do on their own.

Pen Fouling in Finisher Pigs: Changes in the Lying Pattern and Pen Temperature Prior to Fouling

Pen fouling, where the pigs choose to rest in their designated excretion area (the slatted floors) and excrete in their designated resting area (the solid floors), is an undesired behaviour and should be prevented when possible. One strategy to prevent fouling is early detection by means of either animal or environmental measures changing prior to fouling. The aim of the present study was to investigate whether the lying pattern of pigs and the temperature in the pen changed the last 5 days prior to an event of fouling and whether this differed from pens without an event of fouling (controls). Fouling events was recorded at pen level when at least half of the solid floor was wet with excreta and/or urine (day0). Each fouling pen was paired with a control pen that had not been scored as a fouling pen prior to or at least 1 week after the fouling event. Fouling and control pens were either not provided with straw or provided daily with 150 g of straw per pig. Percentage of pigs lying on the solid floor and the slatted floor (36 events) as well as pen temperature above the solid and slatted floor (24 events) was analysed using four linear mixed effects models. The percentage of pigs lying on the solid floor decreased (40–24%; P < 0.05) while the number of pigs lying on the slatted floor increased (14–24%; P < 0.05) from day-2 to day0 only in the fouling pens, with differences seen between fouling and control pens on the same days (P < 0.01). However, these changes and differences was only seen in pens without straw. Also only in pens without straw did pen temperature above the solid floor decrease from day-2 to day0 (18.6–17.6°C; P < 0.001), with differences seen between fouling and control pens only on day0 (P < 0.05). In contrast, pen temperature measured above the slatted floor did not change, independent of whether the pen was provided with straw or not. Thus, in pens not provided with straw, both the lying pattern of pigs and pen temperature above the solid floor have potential as early detectors of pen fouling.

Monitoring of behavior, sex hormones and boar taint compounds during the vaccination program for immunocastration in three sire lines

Immunocastration (vaccination against boar taint) is an alternative method to prevent boar taint without the need for surgical castration. This study investigates the evolution of boar taint compounds in serum and fat, serum steroid compounds as well as behavior in immunocastrated pigs from 3 sire lines: 15 stress positive Belgian Piétrain (BP), 20 stress negative French Piétrain (FP), and 20 stress negative Canadian Duroc (CD). Hormone and boar taint compounds in serum were determined at 4 time points; boar taint compounds in fat were determined at 3 time points. Behavior, skin lesions, animal and pen fouling were also recorded before the first vaccination (<V1), between the first and second vaccination (<V2), and after the second vaccination (>V2). Aggressiveness, eating and drinking and general activity behavior declined from <V1 to <V2 and > V2 for all sire lines. Pigs from BP were cleaner than FP and CD pigs. Even though immunocastration was effective in general (reduced testosterone, estradiol as well as androstenone in serum) for all sire lines, some individual pigs showed either androstenone or skatole levels in fat above cutoff values. While the immunocastration mechanism works as intended for androstenone, and also for skatole for the three sire lines, the risk of carcasses with boar taint compounds above cutoff levels (respectively 1.9 and 3.7%) still remains to some extent.

Spatial modeling of pigs’ drinking patterns as an alarm reducing method II. Application of a multivariate dynamic linear model

The objectives of this paper are to evaluate the detection performance of a previously developed multivariate spatial dynamic linear model (DLM), which aim to predict outbreaks of either diarrhea or pen fouling amongst growing pigs, and to discuss potential post processing strategies for reducing alarms. The model is applied to sensor based water data from a commercial herd of finisher pigs (30–110 kg) and a research facility herd of weaner pigs (7–30 kg). Performance evaluation is conducted by applying a standardized two-sided Cusum, on the forecast errors generated by the spatial model. For each herd, forecast errors are generated at three spatial levels: Pen level, section level, and herd level. Seven model versions express different temporal correlations in the drinking patterns between pens and sections in a herd, and the performances of each spatial level are evaluated for every model version. The alarms generated by the Cusum are categorized as true positive (TP), false positive (FP), true negative (TN), or false negative (FN) based on time windows of three different lengths. In total, 126 combinations of herds, spatial levels, model versions, and time windows are evaluated, and the performance of each combination is reported as the area under the ROC curve (AUC). The highest performances are obtained at herd level given the longest time window and strongest temporal correlation (AUC = 0.98 (weaners) and 0.94 (finishers)). However, the settings most suitable for implementation in commercial herds, are obtained at section level given the medium-length time window and strongest temporal correlation (AUC = 0.86 (weaners) and 0.87 (finishers)). The combination of a spatial DLM and a two-sided tabular Cusum has high potential for prioritizing high-risk alarms as well as for merging alarms from multiple pens within the same section into a reduced number of alarms communicated to the caretaker. Thus, the spatial detection system described here, and in a previous paper, constitute a new and promising approach to sensor based monitoring tools in livestock production.

Operationalizing Principle-Based Standards for Animal Welfare-Indicators for Climate Problems in Pig Houses.

Simple SummaryDutch farms that probably do not comply with the legal principle-based standard for climate in pig houses can be identified based on a limited set of measurements. The results may encourage pig farmers to improve climatic conditions, but can also justify subsequent investigation to substantiate noncompliance with the legal animal welfare standards. This was concluded after farm data collection by inspectors on 96 farms with weaners or growing–finishing pigs. Analysis of the data revealed that CO2 and NH3 concentrations; pig fouling; and ear, tail, and eye scores can be used as indicators of suboptimal climatic conditions.The Dutch animal welfare law includes so-called principle-based standards. This means that the objective is described in abstract terms, enabling farmers to comply with the law in their own way. Principle-based standards are, however, difficult for the inspection agency to enforce because strict limits are missing. This pilot project aimed at developing indicators (measurements) to assess the climate in pig houses, thus enabling the enforcement of principle-based standards. In total, 64 farms with weaners and 32 farms with growing–finishing pigs were visited. On each farm, a set of climate-related measurements was collected in six pens. For each of these measurements, a threshold value was set, and exceeding this threshold indicated a welfare risk. Farm inspections were carried out during winter and spring, thus excluding situations with heat stress. Assessment of the variation and correlation between measurements reduced the dataset from 39 to 12 measurements. Using a principal components analysis helped to select five major measurements as warning signals. The number of exceeded thresholds per pen and per farm was calculated for both the large (12) and small (five) sets of measurements. CO2 and NH3 concentrations were related to the outside temperature. On colder days, there was less ventilation, and thus CO2 and NH3 concentrations increased. Air quality, reflected in the CO2 and NH3 concentrations, was associated with respiratory problems. Eye scores were positively correlated with both pig and pen fouling, and pig and pen fouling were closely related. We selected five signal indicators: CO2, NH3, and tail and eye score for weaners and finishers, and added ear score for weaners and pig fouling for growing–finishing pigs. The results indicate that pig farms can be ranked based on five signal indicators related to reduced animal welfare caused by climatic conditions. This approach could be adopted to other principle-based standards for pigs as well as for other species.

Drinker position influences the cleanness of the lying area of pigs in a welfare-friendly housing facility

Understanding eliminative behaviour in pigs is a priority for designing pig facilities. Pigs prefer to lie in areas separated from where they eliminate (urinate, defecate). Welfare-friendly housing facilities include separate areas for lying (solid floors) and elimination (slatted floors). To prevent pen fouling, ways to reduce the amount of eliminative behaviour on the solid floor area are essential. This study investigated whether the position of the drinkers influences areas preferred for eliminative behaviour in growing-finishing pigs (n=432; over two batches) assigned to one of three drinker treatments: two drinkers placed in the inner slatted area (IN group; n=8 pens), two drinkers in the outer slatted area (OUT group; n=8 pens), or a drinker in each of the inner and outer slatted areas (IN_OUT group; n=8 pens). We predicted that the OUT group would have fewer elimination events on the inner solid area than the IN group. The number of eliminations in the IN_OUT group was predicted to be a compromise between the IN and OUT group patterns. In addition, we quantified the diurnal variation of lying and eliminative behaviour in different pen areas with respect to temperature, and the effect of pigs lying in eliminatory areas on eliminative behaviour. On the solid floor area, the OUT group urinated 32.5% less frequently and defecated 30.4% less frequently than the IN group. For urination preferences, the IN_OUT group was intermediate between IN and OUT groups on the inner solid floor, but not for defecation. No significant differences in lying preferences were found between drinker groups on the inner solid area. Elimination (urination and defecation) was most prevalent in the afternoon (15:00 and 14:00h, respectively) and least prevalent during the night (03:00 and 00:02h, respectively). A one SD increase in temperature (approximately 6°C) was associated with a 42.3% decrease in lying observations on the inner solid area, while the percentage of elimination on the solid floor increased (urination: 75.8%; defecation: 139.5%). Our results showed that the placement of drinkers in the outer area compared to the inner area resulted in less pen fouling (fewer eliminations on the solid floor) and, thus, provided pigs with a cleaner solid area for lying. This study has identified a simple method of increasing the cleanliness of pigs’ dedicated lying areas, which has important implications for improving the design of pig housing facilities and maximising pig welfare.

A multivariate dynamic linear model for early warnings of diarrhea and pen fouling in slaughter pigs

We present a method for providing early, but indiscriminant, predictions of diarrhea and pen fouling in grower/finisher pigs. We collected data on dispensed feed amount, water flow, drinking bouts frequency, temperature at two positions per pen, and section level humidity from 12 pens (6 double pens) over three full growth periods. The separate data series were co-modeled at pen level with time steps of one hour, using a multivariate dynamic linear model. The step-wise forecast errors of the model were unified using Cholesky decomposition. An alarm was raised if the unified error exceeded a set threshold a sufficient number of times, consecutively. Using this method with a 7day prediction window, we achieved an area under the receiver operating characteristics curve of 0.84. Shorter prediction windows yielded lower performances, but longer prediction windows did not affect the performance.

Rooting area and drinker affect dunging behaviour of organic pigs

Hygiene is a common problem on outdoor runs of growing organic pigs. Manure and urine are mainly excreted outdoors and tend to spread all over the run. Reducing the soiled surface area may be beneficial to animal welfare, hygiene, ammonia emissions and labour, not only in organic but also in conventional systems. The objective was to reduce the soiled surface area in the pen and to make the outdoor run more attractive for pigs. Introduction of a rooting area and drinker in the outdoor run was tested in a 2×2 factorial design. In total, four replicates were studied in a room with two rows of four pens containing 14 pigs each. More pigs went outdoors in pens with rooting area access than in pens without a rooting area (11.2 vs. 8.5%, P=0.003). This was due to more pigs entering the rooting area and an adjacent slatted floor. Addition of a drinker did not attract more pigs outdoors (P=0.53).The rooting area improved the cleanliness of the whole pen (P<0.001). However, in some cases the rooting area was also used as a dunging area. The area around the additional outdoor drinker was cleaner, but on the whole, pens were dirtier (P=0.011). Introduction of an outdoor drinker resulted in more indoor pen fouling, especially around the indoor drinker (P<0.001). An outdoor rooting area makes the outdoor run more attractive for pigs and reduces the dunging area. This study contributes to the knowledge base on how to reduce the dunging surface in pens for organic pigs.

Studies on preventive strategies and alternative treatments against roundworm in organic pig production systems

Organic and many ‘low input’ production standards for pigs require outdoor access, and as a consequence expose the animals to a wide range of potential endo- and ectoparasite infection sources. Conventional anthelmintics are used to control parasitic infections, but their preventive use is banned by the organic standards. The present paper investigates the potential of prevention of infection through better hygiene. Attempts were made to break the infection cycle through thorough pen cleaning 10 weeks after the pigs had been introduced to the pen. Although pen fouling can be reduced, the level of roundworm ( Ascaris suum) infection was not reduced. Regular deworming with conventional medication is still required in addition to good hygiene.

Effect of a synthetic plate in the lying area on lying behaviour, degree of fouling and skin lesions at the leg joints of finishing pigs

Abstract Flooring type may have a major influence on thermoregulatory behaviour in finishing pigs, as well as on the occurrence of skin lesions at their leg joints and pen fouling. In this study, we compared the lying behaviour, pen fouling and the occurrence of leg lesions in finishing pigs kept in partly slatted pens with a concrete lying area covered with either a non-deformable synthetic plate or a small amount of straw (100g per pig an day), or left bare, whilst controlling for the effects of temperature and pig weight. Eighteen groups of 10 finishing pigs each were kept in six replicates in three pens with different floor types as described above. Lying behaviour was videorecorded for 48h at weights of 80kg. A fouling score for the lying area was estimated daily. Pigs were examined for skin lesions around the carpal and tarsal joints upon introduction into the experimental pens at a mean weight of 28kg (±3.9 S.D.) and four times thereafter at regular intervals until they reached 100kg. Data were analysed using generalised linear mixed-effects models taking the hierarchical experimental design into account. Floor type in the lying area did not affect the proportion of pigs lying laterally or sternally, or huddling. However, the proportion of pigs lying on the slatted floor was higher in pens with synthetic plate flooring compared to those with a straw layer and was even lower in pens with concrete flooring ( p =0.015). Fouling of the lying area increased as room temperatures rose. This increase was sharper in pens with straw on the floor than in those with bare concrete flooring (interaction: p =0.017), but did not differ between pens with a layer of straw and those with a synthetic plate flooring (interaction: p =0.324). The likelihood of pigs having hairless patches or hyperkeratosis on the carpal joints was similar in pens with synthetic plate flooring and in those with a layer of straw , but higher in bare- concrete -floored pens. This pattern was also found with respect to the higher prevalence of adventitious bursae at the carpal joints and wounds at the tarsal joints found in pigs kept in pens with synthetic plate flooring. In conclusion, our results indicate that the synthetic plate flooring studied may cause heat-loss problems, and does not improve floor quality in the lying area as regards skin lesions. From the point of view of pig welfare, it cannot therefore be considered a better alternative to bare concrete floors.

Temperature and body weight affect fouling of pig pens1

Fouling of the solid lying area in pig housing is undesirable for reasons of animal welfare, animal health, environmental pollution, and labor costs. In this study the influence of temperature on the excreting and lying behavior of growing-finishing pigs of different BW (25, 45, 65, 85, or 105 kg) was studied. Ten groups of 5 pigs were placed in partially slatted pens (60% solid concrete, 40% metal-slatted) in climate respiration chambers. After an adaptation period, temperatures were raised daily for 9 d. Results showed that above certain inflection temperatures (IT; mean 22.6 degrees C, SE = 0.78) the number of excretions (relative to the total number of excretions) on the solid floor increased with temperature (mean increase 9.7%/ degrees C, SE = 1.41). Below the IT, the number of excretions on the solid floor was low and not influenced by temperature (mean 13.2%, SE = 3.5). On average, the IT for excretion on the solid floor decreased with increasing BW, from approximately 25 degrees C at 25 kg to 20 degrees C at 100 kg of BW (P < 0.05). Increasing temperature also affected the pattern and postural lying. The temperature at which a maximum number of pigs lay on the slatted floor (i.e., the IT for lying) decreased from approximately 27 degrees C at 25 kg to 23 degrees C at 100 kg of BW (P < 0.001). At increasing temperatures, pigs lay more on their sides and less against other pigs (P < 0.001). Temperature affects lying and excreting behavior of growing-finishing pigs in partially slatted pens. Above certain IT, pen fouling increases linearly with temperature. Inflection temperatures decrease at increasing BW.

Thermal behaviour of growing pigs in response to high temperature and humidity

The effects of high ambient temperatures and humidities on thermal behavioural adaptation and pen fouling of group-housed growing pigs were assessed. Twelve groups of 10 gilts of an average initial body weight (BW) of 61.7 kg were used. During nine experimental days, ambient temperatures were increased by two degrees per day from 16 °C on day 1 to 32 °C on day 9 and fixed at one of three levels of relative humidity (RH) 50, 65, and 80%. Space allowance per pig was 1 m 2. The floor was 60% solid and 40% slatted. Lying, excreting and fouling behaviour were studied using video recordings. During the nine trial days a radar activity meter was used to record the physical activity of each group of 10 pigs every 6 min. A regression model was used to calculate the heat produced by activity from total heat production (HP). The lying position of the pigs was classified, e.g. Lateral, Sternal, Half lateral lying. Excreting behaviour was determined in terms of, e.g. urination and defecation. Furthermore, thermoregulatory lying behaviour (huddling and wallowing) were recorded. All behaviours were determined in terms of frequency and location. Temperature affected lying and excretion behaviours. The number of pigs lying on slatted floor increased with increasing temperature ( p < 0.001). The inflection point temperature (IPt) for the pigs to lie on slatted floor was on average 18.8 °C; below this IPt the pigs remained lying on the solid floor. The heat produced by activity was relatively constant below 24.2 °C, but once this IPt had been exceeded it down turned. Temperature was inversely related to huddling ( p < 0.001) and positively related to wallowing ( p < 0.001). The total excretions on solid floor increased with temperature ( p < 0.05). The number of urinations was inversely related to temperature ( p = 0.13). However, the relative number of urinations on the solid floor increased concomitantly with temperature ( p < 0.05). It can be concluded that high temperatures greatly affect lying and excreting behaviour. At a relatively low temperature, pigs preferred to lie on the slatted floor. At high temperature, there was a clear increase in fouling of the solid floor. At high humidity, changes in behaviours occurred at lower temperatures.