Longitudinal gait development and variability of growing pigs reared on three different floor types

Biomechanical investigation into locomotor pathology in commercial pigs is lacking despite this being a major concern for the industry. Different floor types are used in modern, intensive pig production systems at different stages of the pigs’ production cycle. The general perception holds that slatted and/or hard solid concrete surfaces are inferior to soft straw-covered floors regarding healthy musculoskeletal development. Previous studies have compared pigs housed on different floor types using clinical, subjective assessment of leg weakness and lameness. However, reliability studies generally report a low repeatability of clinical lameness scoring. The objective of this study was to quantitatively assess the long-term effect of pen floors, reflected in the biomechanical gait characteristics and associated welfare of the pigs. A cohort of 24 pigs housed on one of three different floor types was followed from 37 to 90 kg average liveweight, with gait analysis (motion capture) starting at 63 kg. The three floor types were fully slatted concrete, partly slatted concrete and deep straw-bedded surfaces, all located within the same building. Pigs underwent five repeated camera-based motion captures, 7 to 10 days apart, during which 3D coordinate data of reflective skin markers attached to leg anatomical landmarks were collected. Pigs walked on the same solid concrete walkway during captures. One-way ANOVA and repeated measures ANOVA were used to analyse the gait data. Results revealed changes over time in the spatiotemporal gait pattern which were similar in magnitude and direction for the pigs from different floor types. Significant increases in elbow joint flexion with age were observed in all pigs (P⩽0.050; +6°). There were few differences between floor groups, except for the step-to-stride ratio in the hind legs being more irregular in pigs housed on partly slatted floors (P=0.012; 3.6 times higher s.d.) compared with those on 5 to 10 cm straw-bedding in all pen areas. As the level of clinical problems was generally low in this cohort, it may be that floors elicit problems only when there is a primary predisposing factor increasing weakness in susceptible tissues.     

Effect of overlaying rubber on fully slatted concrete floors on hoof health and lying postures in finishing dairy-origin bulls offered two contrasting diets

Fully slatted concrete floors are labour-efficient, cost-effective and thus common in beef cattle housing. However, the welfare of cattle accommodated on them has been questioned. The objective of this study was to evaluate the effect of floor and diet on hoof health and lying behaviours of housed dairy-origin bulls, from a mean age of 8 months to slaughter at 15.5 months old. Forty-eight bulls, which had a mean initial live weight of 212 (SD = 23.7) kg, were allocated to one of four treatments, which consisted of two floors and two diets arranged in a 2 × 2 factorial design. The floors evaluated were a fully slatted concrete floor and a fully slatted concrete floor overlaid with rubber, while the diets offered were either a high concentrate diet or a grass-silage-based diet supplemented with concentrates. The mean total duration of the study was 216 days. Floor had no significant effect on claw measurements measured on day 62 or 139. However, bulls accommodated on slats overlaid with rubber had a tendency to have a higher front toe length measured pre-slaughter than those accommodated on concrete slats (P = 0.063). Floor had no significant effect on the net growth of toes or heels during the duration of the study. The number of bruises (P < 0.01) and the bruising score (P < 0.05) were significantly higher on day 62 in bulls accommodated on fully slatted concrete floors than on concrete slats overlaid with rubber, but there was no significant effect of floor on these parameters on day 139 or at the measurement taken pre-slaughter. There was a tendency for bulls accommodated on concrete slats to have a higher probability of having sole bruising at the end of the experiment than those accommodated on slats overlaid with rubber (P = 0.052). Diet had no significant effect on toe length or heel height, number of bruises, or overall bruising score at any time point of the study. There was little evidence in the current study to suggest that bulls lying on fully slatted concrete floors could not express lying postures similar to those on concrete slats overlaid with rubber.     

The effect of diet and covering fully slatted concrete floors with rubber strips on the intake,performance and cleanliness of dairy-origin bulls

Fully slatted concrete floors are prevalent in beef cattle housing. However, concerns have been raised about welfare of cattle accommodated on slats. The objective of this study was to evaluate the effect of diet and floor type on the intake, performance and cleanliness of dairy-origin bulls from a mean age of 8 months to slaughter at 15.5 months old. Forty-eight bulls, which had a mean initial live weight of 212 kg (SD = 23.7), were allocated one of four treatments which consisted of two floors and two diets, arranged in a 2×2 factorial design. The floors evaluated were a fully slatted concrete floor and a fully slatted concrete floor covered with rubber; while the diets offered were either a high concentrate diet or a grass silage-based diet supplemented with concentrates. Over the entire experimental period, floor type had no significant effect on intake. Interestingly, however, when bulls were offered concentrates ad libitum, those accommodated on rubber covered slats consumed more concentrates than those accommodated on concrete slats. No effect of floor type on intake was noted when bulls were offered the grass silage supplemented with concentrate diet. There were no significant interactions between floor and diet on animal performance. Animals accommodated on rubber covered slats had a significantly better performance than those accommodated on concrete slats, as assessed by live weight at slaughter and live weight gain/day (P < 0.01) and estimated carcass gain/day (P < 0.05). The diet offered had no significant effect on animal performance. Bulls accommodated on rubber covered slats were significantly cleaner than those accommodated on concrete slats on day 97 (P < 0.001), but there was no significant effect of floor type when measured at other time points in the experiment. It is concluded from this study that diet has an important role to play in assessing bulls’ responses in performance to the effect of covering concrete slatted floors with rubber. Bulls offered a high concentrate diet had a higher concentrate intake, higher performance but a similar feed conversion ratio (FCR) when accommodated on rubber covered slats compared to those accommodated on fully concrete slatted floors. Animals offered this intensive diet were less efficient (as measured by a higher FCR) than those offered a supplemented grass silage-based diet.     

Assessment of welfare of finishing beef cattle kept on different types of floor after short- or long-term housing

This study aimed at evaluating short- and long-term effects of housing beef cattle on deep litter (DL) or concrete fully slatted floor (FS) on their welfare. Animal-based measures of the Welfare Quality® assessment protocol for cattle were used to assess health status and behaviour of bulls. The assessment was carried out in a large commercial farm on 15 batches of bulls (4 DL and 11 FS) 1 month after their receiving day (short-term) and on 12 batches (three DL and nine FS) the week before slaughter (long-term). Signs of better comfort on deep litter in terms of shorter lying down durations (5.1±0.5 v. 6.5±0.4 s; P<0.05) and lower risk of hairless patches (odds ratio=0.09; 95% confidence interval=0.01 to 0.68; P<0.05) were already observed after 1 month. Heavy bulls after a long-term housing on FS showed a higher prevalence of bursitis, hairless patches and lesions/swellings than animals on DL. Bulls on fully slatted floor were at higher risk of early culling (odds ratio=6.44; 95% confidence interval=1.57 to 26.37; P<0.01), mainly due to musculoskeletal system pathologies/lameness. Deep litter proved to be a valid alternative to slatted floor, making animals more confident to interact with powerful movements such as mounting at the end of the finishing period. A negative aspect of the deep litter was the poor cleanliness of the bulls. Compared with the fully slatted floor, there were higher odds ratios for dirty bulls at both, the short- (odds ratio=25.09; 95% confidence interval=8.96 to 70.22; P<0.001) and the long-term housing (odds ratio=276.13; 95% confidence interval=98.21 to 776.38; P<0.001). In order to improve health and welfare of beef cattle finished at a heavy weight, deep litter systems are a promising alternative to fully slatted floors. However, proper management of deep litter is necessary to maintain satisfactory cleanliness of the bulls.     

Synthetic rubber surface as an alternative to concrete to improve welfare and performance of finishing beef cattle reared on fully slatted flooring

The aim of this study was to compare a fully slatted concrete floor (concrete slatted (CS)) with the same floor on which synthetic rubber slats were placed on the concrete slats (rubber slatted (RS)) as housing solution for finishing beef cattle. The present study involved five commercial beef cattle farms in which the floor of at least three pens was kept as fully slatted, and in an equal number of pens a rubber cover was placed on the floor, tightly matching the gap profile of the concrete slats to allow the drainage of manure. A total of 326 finishing beef bulls were used (153 on CS and 173 on RS), and regardless of the floor treatment animals were housed in groups of 6 to 12 bulls/pen with a space allowance of 3.1±0.2 m²/bull. Bulls had similar initial live weights (422.3 kg on CS and 425.0 kg on RS), but bulls on RS were heavier at the end of the finishing period with a higher average daily gain than bulls kept on CS (1.53 v. 1.46 kg/day; P<0.05). The proportion of bulls treated for locomotor problems was lower in RS pens compared with CS. Rubber covering prevented the occurrence of bursitis, but it increased the odds for hoof overgrowth at end of the finishing period. Hoof overgrowth detected in vivo in bulls on RS was confirmed at the slaughterhouse by the longer dorsal wall and diagonal lengths of the hoof as well as by a more acute toe angle. Compared with bulls on CS, bulls on RS showed less inactivity and resting time, increased social interactions, decreased abnormal lying down and unsuccessful attempts to lie down, as well as shortened the time for lying down. Bulls in RS pens were dirtier compared with those in CS pens, likely due to the draining gaps being reduced to 11.6±1.2% of the total pen surface compared with the 16.9±1.7% in CS pens. This study gave further evidence about the positive effects of the RS floor on growth performance and welfare of finishing beef cattle, although compromising cleanliness and hoof overgrowth.     

Quantitative assessment of the effects of space allowance, group size and floor characteristics on the lying behaviour of growing-finishing pigs

To obtain quantitative information that can be later used in animal welfare modelling, the relationship between the lying behaviour of growing-finishing pigs (initial body weight (BW) between 19 and 87 kg) and different factors related to the housing conditions, with a potential negative effect on their welfare, was studied by means of a meta-analytical approach. Data from 22 experiments reported in 21 scientific publications were collected. The space allowance, expressed on an allometric basis by means of a k-value (m2/BW0.667), the group size (n) and the floor characteristics (fully and partly slatted v. non-slatted floor), as well as their significant two-way interactions were used as fixed effects, and the experiment was used as a random factor to take into account the interexperiment effect. Further regression analyses were performed on the predicted values of observations in order to improve the adjustment of data. A significant quadratic relationship was established between space allowance (k-value, P < 0.05; squared k-value, P < 0.01) and the percentage of time spent lying. A significant interaction between the k-value and the floor type was also found (P < 0.05), showing that the relationship between space allowance and lying behaviour is affected by the presence or absence of slats. Threshold k-values were obtained using broken-line analyses, being about 0.039 for slatted floors and almost double for non-slatted floors. Compared to other studies, these values suggest that the ability to rest as space availability decreases may be compromised before a reduced performance becomes apparent. Group size did not show a significant effect. Additional information should be added to the model, as further data become available, to adjust the proposed parameters as well as to try to include the effect of other important aspects such as that of ambient temperature.     

The impact of floor type on lameness and hoof health of dairy origin bulls

This study aimed to evaluate the effect of using different floor types to accommodate growing and finishing beef cattle on lameness. In all, 80 dairy origin bulls were blocked according to live weight and breed into 20 groups, and randomly allocated within groups to one of four treatments. The floor types studied were fully slatted flooring throughout the entire experimental period (CS); fully slatted flooring covered with rubber strips throughout the entire experimental period (RS); fully slatted flooring during the growing period and then moved to a solid floor covered with straw bedding during the finishing period (CS-S) and fully slatted flooring during the growing period and then moved to fully slatted flooring covered with rubber strips during the finishing period (CS-RS). The total duration of the study was 204 days. The first 101 days was defined as the growing period, with the remainder of the study defined as the finishing period. During the growing period, there was a tendency for bulls accommodated on CS to have a higher locomotion score compared with those accommodated on RS (P=0.059). However, floor type had no significant effect on locomotion score during the finishing period. There was also no significant effect of floor type on digital dermatitis during both the growing or finishing period. Floor type had no significant effect on swelling at the leg joints at the end of the finishing period. Bulls accommodated on RS had the least probability of bruised soles during both the growing and finishing period (P<0.01). Growing bulls accommodated on CS had significantly greater front heel height net growth compared with those accommodated on RS (P<0.05). However, bulls accommodated on RS had a tendency to have greater front toe net growth compared with those accommodated on CS (P=0.087). Finishing bulls accommodated on CS-RS had the greatest front toe net growth (P<0.001). Heel height net growth was greatest in bulls accommodated on CS-S (P<0.001). Floor type had no significant effect on mean maximum hoof temperature during the growing period. Finishing bulls accommodated on CS-S had a significantly lower mean maximum hoof temperature compared with those accommodated on any other floor type (P<0.001). The study concluded that rubber flooring is a suitable alternative to fully slatted flooring, reducing the prevalence of bruised soles. Despite greater toe net growth in bulls accommodated on rubber flooring, there was no effect of floor type on locomotion score, suggesting that increased toe net growth does not adversely affect walking ability. In addition, although mean maximum hoof temperature was lowest in bulls accommodated on straw bedding, there was no evidence to suggest this is indicative of improved hoof health.     

Effects of two stall flooring systems on the behaviour of tied dairy cows

Effects on dairy cow behaviour of a new type of flooring in tie-stalls, with the ability to drain faeces and urine, was studied in a controlled randomised trial in one Swedish university herd. Forty-two Swedish Red and White cows were kept tied in traditional long-stalls (2.20m). In 21 stalls (one stall row), the rearmost 0.74m of the solid stall floor had been replaced with nine rubber-coated 53mm wide slats, divided by 29mm slots. Stalls with rubber slats were equipped with 20mm ethyl-vinyl-acetate (EVA) mats in the front part and littered with 0.7kg of wood shavings daily, while stalls with a solid floor had standard rubber mats and received 3kg of chopped straw daily as bedding. Behaviour was compared between the two stall types, using video recordings of 12 matched pairs of cows for two complete 24h periods each. Statistical analysis was done using the Student's t-test for matched pairs or the sign test. Cows on the rubber slatted flooring lie down and rise normally and without any increased risk of slipping. They lay down more comfortably, i.e. spent on an average 23% less time preparing to lie down, and slipped less frequently during rising. There was some evidence of a preference for a solid floor when lying.     

The effect of floor type on the performance,cleanliness, carcass characteristics and meat quality of dairy origin bulls

The aim of this study was to evaluate the effect of using different floor types to accommodate growing and finishing beef cattle on their performance, cleanliness, carcass characteristics and meat quality. In total, 80 dairy origin young bulls (mean initial live weight 224 kg (SD=28.4 kg)) were divided into 20 blocks with four animals each according to live weight. The total duration of the experimental period was 204 days. The first 101 days was defined as the growing period, with the remainder of the study defined as the finishing period. Cattle were randomly assigned within blocks to one of four floor type treatments, which included fully slatted flooring throughout the entire experimental period (CS); fully slatted flooring covered with rubber strips throughout the entire experimental period (RS); fully slatted flooring during the growing period and moved to a solid floor covered with straw bedding during the finishing period (CS-S) and fully slatted flooring during the growing period and moved to fully slatted flooring covered with rubber strips during the finishing period (CS-RS). Bulls were offered ad libitum grass silage supplemented with concentrates during the growing period. During the finishing period, bulls were offered concentrates supplemented with chopped barley straw. There was no significant effect of floor type on total dry matter intake (DMI), feed conversion ratio, daily live weight gain or back fat depth during the growing and finishing periods. Compared with bulls accommodated on CS, RS and CS-RS, bulls accommodated on CS-S had a significantly lower straw DMI (P<0.01). Although bulls accommodated on CS and CS-S were significantly dirtier compared with those accommodated on RS and CS-RS on days 50 (P<0.05) and 151 (P<0.01), there was no effect of floor type on the cleanliness of bulls at the end of the growing and finishing periods. There was also no significant effect of floor type on carcass characteristics or meat quality. However, bulls accommodated on CS-S had a tendency for less channel, cod and kidney fat (P=0.084) compared with those accommodated on CS, RS and CS-RS. Overall, floor type had no effect on the performance, cleanliness, carcass characteristics or meat quality of growing or finishing beef cattle.     

Effects of milking frequency on lying down and getting up behaviour in dairy cows

The objective of this study was to investigate if cows milked twice per day have more difficulty lying down and getting up and spend less time lying than cows milked three times per day. Seventeen cows of the Swedish Red and White Cattle Breed were studied, seven of which were milked twice daily (2M) and ten were milked three times (3M) daily. They were kept in individual cubicles, that were closed in the rear end with a rope. They had free access to a mixture of silage, hay and concentrate. The individual cows were video-recorded for 24h every fourth week, starting four weeks after calving for four times. The 2M cows stood significantly longer, 128.11min, than the 3M cows, 64.88min, (P<0.01) during the 4h before morning milking. The 2M cows also had a tendency for longer duration of standing rumination (P=0.059) as well as significantly more bouts of standing rumination (P<0.01) during these hours than the 3M cows. The cows in the 3M group spent less time on the getting up movement (P<0.05) during the 4h before morning milking. The distribution of the lying bouts during these 4h differed significantly between the groups, where the 3M cows had fewer lying bouts shorter than 15min and more lying bouts longer than 90min. The results indicate that milking three times a day contributes to increased comfort in high-producing dairy cows.     

The effect of long or chopped straw on pig behaviour

In the EU, pigs must have permanent access to manipulable materials such as straw, rope, wood, etc. Long straw can fulfil this function, but can increase labour requirements for cleaning pens, and result in problems with blocked slatted floors and slurry systems. Chopped straw might be more practical, but what is the effect on pigs’ behaviour of using chopped straw instead of long straw? Commercial pigs in 1/3 slatted, 2/3 solid pens of 15 pigs were provided with either 100 g/pig per day of long straw (20 pens) or of chopped straw (19 pens). Behavioural observations were made of three focal pigs per pen (one from each of small, medium and large weight tertiles) for one full day between 0600 and 2300 h at each of ~40 and ~80 kg. The time spent rooting/investigating overall (709 s/pig per hour at 40 kg to 533 s/pig per hour at 80 kg), or directed to the straw/solid floor (497 s/pig per hour at 40 kg to 343 s/pig per hour at 80 kg), was not affected by straw length but reduced with age. Time spent investigating other pigs (83 s/pig per hour at 40 kg), the slatted floor (57 s/pig per hour) or pen fixtures (21 s/pig per hour) was not affected by age or straw length. Aggressive behaviour was infrequent, but lasted about twice as long in pens with chopped straw (2.3 s/pig per hour at 40 kg) compared with pens with long straw (1.0 s/pig per hour at 40 kg, P=0.060). There were no significant effects of straw length on tail or ear lesions, but shoulders were significantly more likely to have minor scratches with chopped straw (P=0.031), which may reflect the higher levels of aggression. Smaller pigs showed more rooting/investigatory behaviour, and in particular directed towards the straw/solid floor and the slatted floor than their larger pen-mates. Females exhibited more straw and pen fixture-directed behaviour than males. There were no effects of pig size or sex on behaviour directed towards other pigs. In summary, pigs spent similar amounts of time interacting with straw/solid floor when long and chopped straw were provided, and most aspects of pig-directed behaviour and injuries were not affected by straw length. There was an increase in pigs with minor shoulder lesions with chopped straw, perhaps because of increased aggression. The use of chopped straw as an enrichment material for pigs warrants further investigation in larger and more detailed studies.     

Modelling of manure production by pigs and NH3, N2O and CH4 emissions. Part II: effect of animal housing, manure storage and treatment practices

A model has been developed to predict pig manure evolution (mass, dry and organic matter, N, P, K, Cu and Zn contents) and related gaseous emissions (methane (CH4), nitrous oxide (N2O) and ammonia (NH3)) from pig excreta up to manure stored before spreading. This model forms part of a more comprehensive model including the prediction of pig excretion. The model simulates contrasted management systems, including different options for housing (slatted floor or deep litter), outside storage of manure and treatment (anaerobic digestion, biological N removal processes, slurry composting (SC) with straw and solid manure composting). Farmer practices and climatic conditions, which have significant effects on gaseous emissions within each option, have also been identified. The quantification of their effects was based on expert judgement from literature and local experiments, relations from mechanistic models or simple emission factors, depending on existing knowledge. The model helps to identify relative advantages and weaknesses for each system. For example, deep-litter with standard management practices is associated with high-greenhouse gas (GHG) production (+125% compared to slatted floor) and SC on straw is associated with high NH3 emission (+15% compared to slatted floor). Another important result from model building and first simulations is that farmer practices and the climate induce an intra-system (for a given infrastructure) variability of NH3 and GHG emissions nearly as high as inter-system variability. For example, in deep-litter housing systems, NH3 and N2O emissions from animal housing may vary between 6% and 53%, and between 1% and 19% of total N excreted, respectively. Thus, the model could be useful to identify and quantify improvement margins on farms, more precisely or more easily than current methodologies.     

Short- and long-term effects of temporary early cow–calf separation or restricted suckling on well-being and performance in zebu cattle

Information on weaning techniques in the tropics is scarce, particularly regarding the long-term effect of temporary early cow–calf separation or restricted suckling. Therefore, we studied the effects of these two handling practices on well-being and performance at 150 days postpartum in fifteen zebu cow–calf pairs randomly assigned to three treatments. Continuous suckling (CS) where calves remained with their dams from birth to weaning; restricted suckling (RS) calves were allowed to suckle 30 min/day from Day 34 until weaning at Day 150 and kept separated the rest of the time; temporary separation (TS) calves were separated for 72 h from their dams from Day 33 to 36 but remained with their dams the rest of the time. Blood samples and behavioral data were collected on Days 32–36 (1st period) and 149–153 (2nd period). In the 1st period, a greater percentage of RS and TS calves were observed close to the fence line (< 10 m) that separated them from their dams (P < 0.0001) and vocalized more than CS calves (P < 0.0001), while in the 2nd period, RS calves had the highest cortisol concentration and vocalization rate (P < 0.05). Similarly, during the 1st period, a greater percentage of RS and TS cows were observed close to the fence line than CS cows (P < 0.0001), with TS cows vocalizing the most (P = 0.001). In the 2nd period, RS cows had greater cortisol concentration than TS (P = 0.037) and CS cows (P = 0.003). More TS and CS cows than RS were observed close to the fence line (P = 0.03 and P = 0.05). On Day 150, TS calves and cows vocalized more than RS and CS animals (P < 0.0001). Before calf–cow separation, 27 out of 45 cows were cycling (CS = 10; RS = 6; TS = 11). After separation, 12 of the remaining 18 cows resumed ovarian activity (CS = 3; RS = 5; TS = 4), and all cows were cycling after estrous synchronization treatment. The pregnancy rate was similar between CS, RS, and TS (60, 53, and 60% respectively). In conclusion, temporary separation increased calf distress response to definitive weaning even four months later, while restricted suckling seemed to reduce it.     

Biomechanical gait analysis of pigs walking on solid concrete floor

Inappropriate floors in pig pens and slippery floor conditions may cause leg problems that reduce animal welfare. Therefore the objectives of the present study were to characterise the walk of pigs on dry concrete solid floor, to evaluate whether pigs modify their gait according to floor condition, and to suggest a coefficient of friction (COF) that ensures safe walking on solid concrete floors for pigs. Kinematic (50 Hz video recordings in the sagittal plane) and kinetic (1 KHz force plate measuring three perpendicular ground reaction forces) data were collected from four strides of both the fore- and hindlimbs of 30 healthy pigs walking on dry, greasy and wet concrete floor with 10 pigs on each floor condition. The COF of the floor conditions were tested in a drag-test. The results from the gait analysis showed that the pigs adapted their gait to potentially slippery floors by lowering their walking speed and reducing their peak utilised COF on greasy and wet (contaminated) floors compared with dry floors. Moreover, the pigs shortened their progression length and prolonged their stance phase duration on greasy floor compared with dry and wet floors. Thus the greasy floor appeared the most slippery condition to the pigs, whereas the wet floor was intermediate to the other two conditions. The pigs walked with a four-beat gait, and the limbs differed biomechanically, as the forelimbs carried more load, received higher peak vertical forces and had longer lasting stance phases than did the hindlimbs. The utilised COF from the gait analysis indicated that a high floor COF (>0.63) is needed to prevent pigs from slipping and thus to ensure safe walking on dry concrete floors.     

Trade-off between floor level and floor material in farmed silver foxes

Farmed silver foxes (Vulpes vulpes) were allowed to balance their known preference for an elevated floor against their presumed preference for a sand floor. In Experiment 1, foxes had to choose between two identical cages, connected with an opening. One cage had a wire floor and the other had a sand floor, but the cages either were on the same (low or elevated) or on different levels (one cage 40 cm higher than the other). In Experiment 2, the cage pairs were connected with a 1.2 m long wire-mesh tunnel, one cage was always on a higher level (50 cm) than the other. In Experiment 1, foxes always preferred the sand floor during their active time. They also preferred the sand floor for resting, if it was on the same level as wire floor, but did not show any genuine preference if the floors were on different levels. In Experiment 2, foxes never preferred the lower floor. They preferred the elevated sand floor for activity and the elevated wire floor for lying. When two floors were identical they preferred the elevated one. Their rest consisted of 11-22 bouts, a major part of these being spent in the preferred cage. They also preferred a previous lying site to a new one, often exclusively and independently of floor material. In Experiment 1 foxes preferred the sand floor whereas in Experiment 2 they preferred the elevated floor indicating that the ability of a trade-off situation to rank resources depends on the method it is inflicted.     

Effect of straw amount on feed intake and weight gain in growing pigs housed in pens with partly slatted floor

The provision of straw to pigs kept in conventional pens with concrete floor improves animal welfare, but the effects of straw on pigs’ performance are unclear. In two steps, we investigated the relationship between amount of straw provided to pigs and measures of performance in a set-up maintaining constant space allowance and controlled room temperature. From approximately 30- to 85-kg BW, pigs were housed in groups of 18 in pens (5.48 m × 2.48 m) with concrete floor (1/3 solid, 1/3 drained and 1/3 slatted). The pens were cleaned manually twice a week, and the designated amount of fresh uncut wheat straw was provided daily onto the solid part of the floor. In the first step, 48 pens were assigned to 10-, 500- or 1000-g straw per pig per day, while in the second step, 90 pens were assigned to 10-, 80-, 150-, 220-, 290-, 360-, 430- or 500-g straw per pig per day. Pigs were weighed at the start of the experimental period at approximately 30 kg and again at approximately 85-kg BW. The average daily gain increased 8.1 g (SEM 17) for every extra 100-g straw added daily (P < 0.001) resulting in 40 g higher average daily gain with 500 compared to 10-g straw per pig per day. The feed conversion ratio was not affected by the amount of straw provided, as the feed intake tended to be higher with increasing amounts of straw. Thus, between 10 and 500 g, the more straw provided, the higher the daily weight gain. As the nutritional value of straw is considered minimal, this result is likely due to improved gut health from the increasing amounts of straw ingested and increased feed intake due to increased stimulation of exploratory behaviour with increasing amounts of straw available, or a combination of these. The observed tendency for a higher feed intake supports this suggestion, but studies are needed to establish the impact of these two contributing factors.     

The effect of fenceline bull exposure on expression of oestrus in dairy cows

The objective of this study was to investigate whether dairy cows visit and interact with a fenceline-housed bull more during oestrus than outside oestrus and whether fenceline bull contact affects expression of oestrus. At one end of a free stall a fence with vertical open bars was placed behind which a bull could be housed, allowing interactions with the cows. A closed fence with two blinded entrances was placed before the fence, creating a contact area. The experiment consisted of three treatments; it started with the control treatment (no bull on the farm) and was followed by bull treatment (a bull housed behind the fence) and no bull treatment (a bull present on the farm but not housed behind the fence). Signs of oestrus were observed every 4h for 30min and cows were equipped with pedometers. On the day of oestrus, cows were more frequent in the contact area during the bull treatment (12.0+/-9.8 times) and the no bull treatment (13.9+/-10.2 times) than during the control treatment (2.6+/-2.5 times). The frequency of visits to the contact area was low and not different between treatments on the other days (2.2+/-1.9 times). More cows had direct contact with the bull on the day of oestrus (71.4%) compared to the days outside oestrus (21.4-30%). The duration of direct contact with the bull was highly variable between cows and did not differ between oestrus and non-oestrus days. Behaviour and duration of oestrus were not affected by treatment but the relative increase in number of steps during oestrus tended to be higher in the bull (5.5+/-0.2) and no bull treatment (5.3+/-0.3) than in the control treatment (4.6+/-0.3). In conclusion, dairy cows in oestrus seem to be attracted by a bull or by the expectation of the presence of a bull, but fenceline bull exposure does not affect behavioural expression of oestrus.     

Effects of dietary crude protein level on odour from pig manure

The objective of this study was to determine the effects of dietary crude protein (CP) level on odour emission, odour intensity, hedonic tone, and ammonia emission from pig manure and on manure composition (pH, total nitrogen, ammonium, volatile fatty acids, indolic, phenolic and sulphur-containing compounds). An experiment was conducted with growing pigs (n = 18) in a randomised complete-block design with three treatments in six blocks. Treatment groups were 12%, 15% and 18% CP diets. Barley was exchanged for soya-bean meal. Crystalline amino acids (AA) were included in the 12% CP diet up to the level of pigs' requirement; the same amount of AA was added to the 15% and 18% CP diets. Pigs with an initial body weight (BW) of 36.5 ± 3.4 kg (mean ± s.d.) were individually penned in partly slatted floor pens and offered a daily feed allowance of 2.8 × maintenance requirement for net energy (NE: 293 kJ/kg BW^0.75). Feed was mixed with water, 1/2.5 (w/w). Faeces and urine of each pig were accumulated together in a separate manure pit under the slatted floor. After an adaptation period of 2 weeks, the manure pits were cleaned and manure was collected. In the 5th week of the collection period, air samples for odour and ammonia analyses, and manure samples were collected directly from each manure pit. Air samples were analysed for odour concentration and for hedonic value and intensity above odour detection threshold. Manure samples were analysed for volatile fatty acids, and indolic, phenolic and sulphurous compounds, ammonium and total nitrogen concentrations. Reducing dietary CP from 18% to 12% lowered odour emission ( P < 0.05) and ammonia emission ( P = 0.01) from pig manure by 80% and 53%, respectively. Reduced dietary CP decreased total nitrogen, methyl sulphide, carbon disulphide, ethanethiol, phenol, 4-ethyl phenol, indole and 3-methyl indole concentrations in the manure ( P < 0.05). Volatile fatty acids and cresols concentrations in the manure of pigs fed different dietary CP levels were similar. A reduction of dietary CP and at the same time providing essential AA is an option to reduce odour emission as well as ammonia emission from pig manure.     

Characterisation of physiological and immunological responses in beef cows to abrupt weaning and subsequent housing

Background  

Weaning involves the permanent separation of the calf from the dam and has been shown to be stressful for both. The objectives of this study were to characterise the effect of i) abrupt weaning and ii) subsequent housing on the extended physiological and immunological responses of beef cows. At weaning (day (d) 0, mean age of calf (s.d.) 212 (24.5) d), cows were abruptly separated from their calves and returned to the grazing area. After 35 d at pasture, cows were housed in a slatted floor shed and offered grass silage ad libitum plus a mineral-vitamin supplement daily. Rectal body temperature was recorded and blood samples were obtained on i) d 0 (weaning), 2, 7, 14, 21, 28, 35 and subsequently on ii) d 0 (housing), 2, 7, 14 and 21 for physiological, haematological and immunological measurements.     

Effects of semi-group housing and floor type on pododermatitis,spinal deformation and bone quality in rabbit does

The most common housing system for reproduction rabbits, individual cage housing on a wire floor, is increasingly scrutinized because of its potential detrimental impact on animal welfare. We compared three types of housing: (1) individual cage housing on a wire floor (3952 cm²/doe, maximum roof height 63 cm, one 1000 cm² plastic footrest/doe), (2) semi-group housing on a wire floor (5000 cm²/doe, roofless, one 1000 cm² plastic footrest/doe) and (3) the same semi-group housing, but with a fully plastic slatted floor. In all housing systems, does had free access to an elevated platform. In the semi-group housing pens, four does were housed communally during 21 days of the reproduction cycle (to allow more space for locomotion and to increase opportunities for social contact), and individually during the other 21 days of the cycle (to minimize doe–doe and doe–kit aggression that peaks around kindling). In all, 24 Hycole does were included per system. The does entered the experiment at 203 days of age (after their first parity). The experiment consisted of four reproductive cycles, ending at 369 days of age. Pododermatitis was scored in cycles 1, 2 and 4. At the end of the 4^th cycle the does were euthanized and X-rays were taken to assess spinal deformation. Tibia and femur length, width and cortical thickness were determined and bone strength was assessed using a shear test, as a measure of bone quality. Although severe pododermatitis was absent, the prevalence of plantar hyperkeratosis (hair loss and callus formation) at the end of the 4^th cycle was much greater on the wire floor (65% and 68% for semi-group housing and individual cages, respectively) than on the plastic floor (5%, P<0.0001), even though the wire floors were equipped with a plastic footrest known to decrease hyperkeratosis. In contrast to our expectations, semi-group housing did not affect the prevalence of spinal deformations (P>0.10), but in line with our expectations bone quality was affected favourably by semi-group housing. The tibial cortex (and to a lesser extent the femoral cortex) was thicker in semi-group housing than in individual cages (1.45, 1.46 and 1.38 mm for semi-group housing on wire, semi-group housing on plastic and individual housing on wire, respectively, P=0.045). What this increase in cortical thickness means in terms of doe welfare requires further study, as it may reflect an increase in activity resulting either from increased space for locomotion, or from fleeing aggressive pen mates.