Large Pen Research Articles

Do Rubber Floor Mats Prevent Lameness in Gestating Sows Housed in Large Groups? A Field Experiment on Three Commercial Farms in France.

Simple SummaryIn the European Union, gestating sows are housed in groups in pens that often have slatted floors. Slatted floor can cause injuries to the animals’ legs and hooves, leading to potentially painful lameness. The purpose of our study was to verify if the installation of rubber mats on their floors could limit the occurrence of injuries and lameness in gestating sows. Mats were installed on three commercial farms for use over two consecutive sow pregnancies. The mats limited the occurrence of inflammations around the sows’ leg joints but had no impact on the occurrence of lameness or leg and hoof injuries. The benefit of mats would be greater if they were available throughout the sows’ lives and not just during the gestation period. However, the mat design tested was unsatisfactory because manure did not drain well off the mat and sows were dirtied quickly.Lameness and foot disorders are major health and welfare issues in intensive swine production systems. They are exacerbated when sows are housed in large groups on slatted concrete floors during gestation. Our study aimed to assess the effect of rubber mats in the lying area of the gestation pen on lameness and leg health in gestating sows housed in large pens in commercial conditions. The study was conducted on three commercial farms over two successive gestations. A total of 582 Large White × Landrace sows, housed in 10 static groups, were enrolled: 5 groups in pens with rubber mats and 5 groups on slatted concrete floors. Lameness, bursitis, leg injuries, claw growth defects and claw lesions were measured at the beginning, middle and end of each gestation period. The rubber mats decreased the risk of suffering from bursitis, but had no effect on the risk of lameness, leg injuries, claw growth defects or claw lesions. Sows housed on rubber mats were heavily soiled compared with those on slatted concrete floors because the mats were not perforated for slurry evacuation. Locomotion disorders and foot lesions remained prevalent despite the rubber mats in the lying area of the gestation pens, but adding rubber mats in service rooms and farrowing crates may produce better results.

Health, performance and soiling of breeding does and their kits kept in two different housing systems on a German rabbit farm

<p>The aim of the present study was to compare a new housing (NC) for rabbit does and their kits that complies with German welfare regulations with established wire mesh cages (CC) on a commercial rabbit farm. Rabbit does were single-housed from five days antepartum until weaning at 31 d postpartum either in large pens (80×80 cm with an open top) with slatted plastic flooring (11 mm slats and 11 mm gaps), nestbox, elevated platform (15% perforated) and different manipulable materials (NC) or in cages (70×50×30 cm) with wire mesh flooring (12×70 mm holes and 3 mm wire diameter), nestbox and one gnawing stick (CC). Skin lesions, weight development, fertility, morbidity, cleanliness and kit performance of 272 rabbit does in a total of six batches were investigated. While there was no difference in performance of their kits, rabbit does showed an impaired performance with less weight gain and less body weight at weaning, lower fertility, more injuries and a higher incidence of mastitis and diarrhoea at the end of the rearing period in NC housing compared to CC housing. Additionally, soiling of hind feet was higher in NC than in CC housing. Overall, the poor hygienic conditions may have affected the animals’ health and make an improvement in the new housing system necessary, especially with regard to the floor design.</p>

Effect of environmental enrichment and group size on the water use and waste in grower-finisher pigs

The grower-finisher stage accounts for 64% of the total on-farm herd water use. Part of this is consumed by the pigs, but a part is also wasted. Drinking water usage and wastage is affected by different factors. We investigated how different group sizes and different levels of enrichment affect water usage (ingested plus wasted), water wastage, behavior and performance in grower-finisher pigs. Pigs (n = 672), 11 weeks of age (77 ± 2 days) were used for the experiment. The effect of group size: SMALL (12 pigs), MEDIUM (24 pigs), and LARGE (48 pigs) was assessed across two levels of enrichment (LOW—wooden post, hanging rubber toy, HIGH—Same as LOW + fresh grass). There was no effect of group size on water use or wastage. Pigs with HIGH enrichment (10.4 ± 0.4 L/pig/day) used less water than LOW enrichment (11.0 ± 0.4 L/pig/day; p < 0.001). The water wastage/drinker/hour was lower in pens with HIGH enrichment than LOW (p = 0.003). The drinking bout number (p = 0.037) and total occupancy/hour (p = 0.048) was also higher for pens with LOW than HIGH enrichment. Aggressive and harmful behaviour were performed less in LARGE groups and pens with HIGH enrichment. Thus, HIGH enrichment allowance reduced water usage and wastage so may have benefits for the environment, as well as animal welfare.

1 Daily secretion patterns of thyroxine, insulin, and cortisol in non-working horses on pasture when receiving one concentrate meal per day vs. no daily concentrate

Testing of metabolic hormones such as insulin (I), thyroxine (T 4 ), and cortisol (C) has become common in equine veterinary practice as the prevalence of obesity and insulin resistance has increased. There are few reports of daily secretion patterns of these hormones, as well as how diet may impact their secretion; especially in horses on pasture. Therefore, the objective of this study was to assess the daily secretion patterns of I, T 4 , and C in non-working horses on pasture receiving 0 or 1 concentrate meals/d. Sixteen horses (13 geldings and 3 mares; 6 to 22 yr of age; no diagnosed endocrine conditions) were used in a static group comparison. Horses were housed in 1 of 2 large outdoor pens with pasture access 24 h/d. Each pen of horses had ad libitum access to Teff hay and water. One pen of horses received no concentrate [no grain (NG), n = 8] and 1 pen received 2 kg Hi-Pro WTAMU Pellet (Friona, TX) once/d [grain (G), n = 8]. The meal was fed daily at 0700 except on sample collection days, when fed at 1100. The 42-d experiment consisted of 6 7-d periods with 1 sample collection d/period. On each sample collection day, blood samples were collected via jugular venipuncture between 0800 and 1000 (AM), 1200 and 1400 (MD), 1600 and 1800 (PM) h. Data were analyzed using the MIXED procedure of SAS v. 9.4 (SAS Institute, Inc., Cary, NC). No diurnal patterns were observed for T 4 or I, but C exhibited an expected circadian secretion pattern with the greatest concentration observed in the AM and decreasing throughout the day. There was an effect of treatment on plasma T 4 , with greater ( P < 0.001) overall mean T 4 observed in NG (23.2 ± 1.3 ng/mL) compared with G (16.0 ± 1.2 ng/mL). There was an effect of the interaction of treatment, period, and time of day on plasma I ( P < 0.001), with a spike in I during the MD collection following the 1100 meal in G, while NG horses remained relatively low across all 3 collections. There was an effect of the interaction of treatment and time of day ( P = 0.036) on plasma C. Both groups of horses exhibited expected diurnal secretion patterns of C in multiple periods. Horses in the G group appeared to have a greater decrease in C from the AM to MD collection than NG horses in several periods. Results from this experiment indicate that there is no diurnal secretion pattern for T 4 or I but support the presence of the circadian rhythm of C secretion. These results also highlight the influence concentrate meals may have on the outcomes of diagnostic tests and the importance of following a standardized fasting protocol during diagnostic testing.

Eating, drinking and locations of broiler chickens reared under commercial conditions with supplementary feeder line lighting

The study examined the distribution of Cobb 700 broiler chickens in large (1.524 m × 6.096 m) pens under commercial conditions with 2 nipple waterer lines and a single feeder. The light intensity in the house was 4 lx provided by light emitting diode lighting but with supplementary lighting along the feeder line. There was a gradation of light intensity from 100 lx at bird level by the feeders to 4 lx at the edge of the pen. In addition, a limited time budget was estimated. A video system was employed to record the number of birds eating, drinking, standing close (within 30 cm) to the feeder line, standing close (within 30 cm) to the nipple waterers, sitting close to the feeder line and sitting close to the nipple waterers. Numbers were determined by direct observation. The number of birds that were neither close to the feeders nor nipple waterers was calculated by difference (total birds minus number of birds close to feeder plus those close to waterers). Birds congregated close to the feeder: Eating or standing or sitting. However, 56% were situated neither close to the lit feeder line or the nipple waterers. The percentage of the broiler chickens that were feeding and drinking was 12.8 and 8.2%, respectively. There were shifts in bird behavior during the day with more broiler chickens eating and drinking during the first hour of the photophase and fewer birds eating increasing age.

3-Nitrooxypropanol Decreased Enteric Methane Production From Growing Beef Cattle in a Commercial Feedlot: Implications for Sustainable Beef Cattle Production

Effects of the investigational methane (CH4) inhibitor 3-nitrooxypropanol (3-NOP) on animal performance, health and enteric CH4 production of beef cattle were evaluated in a commercial feedlot. Two concurrent studies were conducted: a large pen study (4,048 cattle, eight pen replicates per experimental group) to measure animal performance and health and a small pen study (a subset of 50 cattle from the large pen study, n = 25 per experimental group) to measure enteric CH4 emissions. Within the study, animals (body weight ± SD, 282 ± 8 kg) were assigned in a completely randomized design to one of two groups: control, fed a backgrounding diet (70% corn or barley silage, 30% steam-flaked barley grain concentrate; dry matter (DM) basis) and 3-NOP, fed the backgrounding diet containing 3-NOP. The treatment group in the large pen study was adapted to 3-NOP (12 ± 3 d) before receiving the final target level of 200 mg/kg of DM, which was fed for 108 ± 8 d. Animals in the small pen CH4 emissions study received a basal diet or a basal diet with 3-NOP, with the dose increased every 28 d: low (150 mg/kg DM; 1.27 g/d), medium (175 mg/kg DM; 2.25 g/d), and high (200 mg/kg DM; 2.75 g/d). Intake in the small pens was monitored by electronic feeding bunks and CH4 was measured using the GreenFeed system. In the large pen study, total weight gained, average daily gain, and animal health variables were not affected by 3-NOP, but DM intake (DMI) tended to decrease (P = 0.06) by 2.6% relative to control (8.07 kg/d), while gain:feed ratio tended to be improved (P = 0.06) by 2.5% relative to control (0.161 kg weight gain/kg DMI). In the small pen study, average daily consumption of 3-NOP increased with inclusion rate whereas average DMI was decreased by 5.4% (P = 0.02) compared with control (10.4 kg/d). On average, addition of 3-NOP decreased (P = 0.001) CH4 emissions (g/d) by 25.7% and yield (g CH4/kg DMI) by 21.7%. In conclusion, supplementing a backgrounding diet with 3-NOP decreased CH4 yield and tended to improve feed efficiency of beef cattle fed in a commercial feedlot with no negative impacts on animal health.

A Model System for Feralizing Laboratory Mice in Large Farmyard-Like Pens.

Laboratory mice are typically housed under extremely clean laboratory conditions, far removed from the natural lifestyle of a free-living mouse. There is a risk that this isolation from real-life conditions may lead to poor translatability and misinterpretation of results. We and others have shown that feral mice as well as laboratory mice exposed to naturalistic environments harbor a more diverse gut microbiota and display an activated immunological phenotype compared to hygienic laboratory mice. We here describe a naturalistic indoors housing system for mice, representing a farmyard-type habitat typical for house mice. Large open pens were installed with soil and domestic animal feces, creating a highly diverse microbial environment and providing space and complexity allowing for natural behavior. Laboratory C57BL/6 mice were co-housed in this system together with wild-caught feral mice, included as a source of murine microbionts. We found that mice feralized in this manner displayed a gut microbiota structure similar to their feral cohabitants, such as higher relative content of Firmicutes and enrichment of Proteobacteria. Furthermore, the immunophenotype of feralized mice approached that of feral mice, with elevated levels of memory T-cells and late-stage NK cells compared to laboratory-housed control mice, indicating antigenic experience and immune training. The dietary elements presented in the mouse pens could only moderately explain changes in microbial colonization, and none of the immunological changes. In conclusion, this system enables various types of studies using genetically controlled mice on the background of adaptation to a high diversity microbial environment and a lifestyle natural for the species.

Effect of Pen Size on Stress Responses of Stall-Housed Horses Receiving One Hour of Daily Turnout

Group turnout provides important socializing opportunities for horses, particularly those that are primarily stalled. A high percentage of equine injuries occur during group turnout, which could partly be due to the physical constraints of fencing. To investigate appropriate paddock sizes for group turnouts, horses (n = 12) from a single herd were divided into groups of 4, stalled for 24 hours, and then turned out for 1 hour into one of three differently sized pens: 342, 263, and 184 m2 per horse. Groups rotated through pens across 3 days, receiving one treatment per day. Blood was sampled for cortisol concentrations at 08:00 hours each morning, and then at 15 and 60 minutes into the turn out sessions, and 60 minutes after return to individual stalls. Groups rotated through three turnout times: 09:00, 12:00, 14:00 hours. Counts of agonistic behaviors (chasing, contact biting, and kicking) and low-level threats (pinned ears, tail swishing, bite and kick threats) were recorded. When turned out in pens that provided 342 m2 per horse, horses exhibited reduced plasma cortisol concentrations by 15 minutes after turnout and at 1 hour after return to their stalls (P < .05). Horses in pens providing 184 m2 per horse exhibited greater agonistic (P < .001) and low-level threat (P < .01) behaviors than horses in larger pens. These data provide insight into appropriate pen sizes for horses from established herds. Providing at least 342 m2 per horse may reduce the chance of injury in horses accustomed to group turnout.

Characterization of swine behavior and production using measurements collected via indoor positioning system

Legislative and market initiatives are requiring that gestating sows move from individual housing to group settings. Little information is known about coping of individual sows in these more socially complex environments and thus the impact of different behaviors on sow reproductive success was investigated. The movements of 70 sows during periods of reintroduction into large pen gestational housing following insemination was measured using Smartbow indoor positioning technology (Smartbow, Smartbow GmbH, Weibern, Austria) that tracked animal location and accelerations. Principle component analysis (PCA) was used to establish composite variables characterizing each animal’s behavioral response to social reintroduction and revealed the presence of two new variables accounting for over 60 % of the variance in behaviors: one pertaining to total movement and the other pertaining to social dominance/rapid movements. Component scores of total movement predicted measures of reproductive success whereas social dominance/rapid movements predicted piglet birth weight. These findings suggest that differences in behavioral variables as measured by Smartbow’s automated, non-invasive, real time tracking system are correlated with productivity of sows housing in socially complex settings.

PSVI-6 Effect of reduced dietary protein and amino acid supply imposed in the grower and finisher period or solely in the finisher period on growth traits and carcass protein deposition efficiency in pigs

Abstract Above 65 kg empty BW, protein deposition is greater in pigs fed protein-restricted compared to standard diets. It is unclear whether the greater CP deposition rate in the finisher period results from the restricted CP supply in the grower period. To elucidate this question, a growth performance study (22.1-110.0 kg BW) was performed with 48 Swiss Large White pigs. They were assigned to either treatment C, LPF or LPGF. The grower-finisher diets of treatment C were formulated based on the Swiss feeding recommendations whereas those of treatment LPGF contained 20% lower digestible CP and essential amino acid levels than diets C. Pigs of the LPGF treatment were offered in the grower and finisher period the standard and the low CP diets, respectively. The pigs were reared in 1 large pen, equipped with 6 automatic feeders, which allowed measuring the individual ad-libitum feed intake per visit. The BW was determined weekly and carcass composition at slaughter was determined by dual-X-ray-absorpiometry. Growth performance and dual-X-ray-absorpiometry data were analyzed with a linear mixed model using treatment as fixed and litter, litter size and farrowing series as random effects. Despite total CP intake was 6 and 16% lower (P&amp;lt; 0.05) in the LPGF than the LPF and C groups, respectively, overall ADG among treatments did not differ. In accordance, gain-to-CP-intake ratio was 9 and 20% greater (P&amp;lt; 0.05) in the LPGF than the LPF and C group. The carcass protein content did not differ whereas carcass fat content was 9% greater (P&amp;lt; 0.05) in LPGF than LPF and C pigs. Carcass protein deposition efficiency was 0.5 and 6.7%-units greater (P&amp;lt; 0.05) in LPGF than LPF and C pigs, respectively. In conclusion, lowering the CP supply by 20% in the grower and finisher compared to solely the finisher period or not at all has no detrimental effect on growth performance, markedly improves CP utilization for carcass protein deposition but slightly increases carcass fatness.

154 The effect of number of cattle per pen on stocker cattle health and performance

Abstract The objectives of this study were to: 1) to examine the effect of number of stocker cattle in a receiving pen on BRD morbidity and mortality; and 2) to examine the effect of number of stocker cattle in a receiving pen on cattle performance. Crossbred steers of unknown origin and history (n = 200) were purchased from auction barns in the southern portion of the United States. Cattle were stratified by weight and assigned to either a small (10 head/pen) or large (50 head/pen) treatment on arrival. Calves were assigned to 1 of 3 large pens or 1 of 5 small pens. Cattle were observed daily for clinical signs of BRD and treated if rectal temperature ≥40°C. Body weight was collected on d 0, 14, 28, 42, and 56. Rectal temperature was collected at arrival. Days-at-risk for BRD was the number of days from arrival until a calf: (1) was first diagnosed with BRD; (2) died; or (3) finished the trial. Treatment effects on BRD incidence and performance were tested using Poisson distribution and logistic regression using GLIMMIX or linear regression using MIXED procedure of SAS, respectively, accounting for clustering by pen. Mortality was analyzed using the LOGISTIC function with Firth’s penalized likelihood. There were 8,698 total days at risk and overall incidence density was 7.82 BRD cases per 1,000 calf days. Overall morbidity totaled 32.5% with 5.5% mortality. No difference among treatment was observed for morbidity, mortality, or performance. Cattle with fever on arrival were 1.125 times more likely to contract BRD (P ˂ .0001). The number of BRD treatments received had an effect on ADG at d 0–14 (P ˂ .0001), 0–28 (P ˂ .0001), and 0–60 (P ˂ .0001), with ADG decreasing as number of treatments increased. In summary, fever on arrival affected BRD incidence, and number of treatments cattle received affected growth throughout the trial.

155 The effect of number of cattle per pen on stocker cattle health and performance

Abstract The objectives of this study were to: 1) to examine the effect of number of stocker cattle in a receiving pen on BRD morbidity and mortality; and 2) to examine the effect of number of stocker cattle in a receiving pen on cattle performance. Crossbred steers of unknown origin and history (n = 200) were purchased from auction barns in the southern portion of the United States. Cattle were stratified by weight and assigned to either a small (10 head/pen) or large (50 head/pen) treatment on arrival. Calves were assigned to 1 of 3 large pens or 1 of 5 small pens. Cattle were observed daily for clinical signs of BRD and treated if rectal temperature ≥40°C. Body weight was collected on d 0, 14, 28, 42, and 56. Rectal temperature was collected at arrival. Days-at-risk for BRD was the number of days from arrival until a calf: (1) was first diagnosed with BRD; (2) died; or (3) finished the trial. Treatment effects on BRD incidence and performance were tested using Poisson distribution and logistic regression using GLIMMIX or linear regression using MIXED procedure of SAS, respectively, accounting for clustering by pen. Mortality was analyzed using the LOGISTIC function with Firth’s penalized likelihood. There were 8,698 total days at risk and overall incidence density was 7.82 BRD cases per 1,000 calf days. Overall morbidity totaled 32.5% with 5.5% mortality. No difference among treatment was observed for morbidity, mortality, or performance. Cattle with fever on arrival were 1.125 times more likely to contract BRD (P ˂ .0001). The number of BRD treatments received had an effect on ADG at d 0–14 (P ˂ .0001), 0–28 (P ˂ .0001), and 0–60 (P ˂ .0001), with ADG decreasing as number of treatments increased. In summary, fever on arrival affected BRD incidence, and number of treatments cattle received affected growth throughout the trial.

Characteristics of Medical School Applicants: A Single-Institution Study.

Medical schools aim to admit talented learners who are honest, patient centered, and caring, in addition to possessing the required cognitive skills. The Association of American Medical Colleges (AAMC) describes core competencies for entering medical students in three categories: science, preprofessional, and thinking and reasoning. The authors sought to determine desired characteristics of medical school applicants at a rural, community-based medical school in light of the published core competencies. This qualitative study involved an analysis of data from discussion groups, all from a convenience sample of participants. The authors led the discussion groups, and large sticky note pads and pens were provided to scribe responses. Group members were given the prompt, "What do you see as traits or characteristics of your ideal doctor?" We used a content analysis approach to analyze the data. The total number of responses across groups was 243, representing 15 unique characteristics. The 15 characteristics, listed in decreasing order of frequency, included good communicator, knowledgeable, dedicated, compassionate, respectful, community oriented, well rounded, patient, team player, available, leader, positive attitude, equal treatment, prevention focused, and urgency when needed for patient care. Of the top characteristics with 20 or more responses, alignment with AAMC competencies was noted, but less so with being community oriented as defined by study participants. This study demonstrates that there are unique characteristics that a rural community and its medical school consider when admitting applicants to their medical program. Further research is needed to explore the need for additional competencies for rural medical schools to consider for entering medical students.

Modeling the Effect of Tylosin Phosphate on Macrolide-Resistant Enterococci in Feedlots and Reducing Resistance Transmission.

Tylosin phosphate (TYL) is administered to more than 50% of U.S. beef cattle to reduce the incidence of liver abscesses but may increase the risk of macrolide-lincosamide-streptogramin-resistant bacteria disseminating from the feedlot. Limited evidence has been collected to understand how TYL affects the proportion of resistant bacteria in cattle or the feedlot environment. We created a mathematical model to investigate the effects of TYL administration on Enterococcus dynamics and examined preharvest strategies to mitigate the impact of TYL administration on resistance. The model simulated the physiological pharmacokinetics of orally administered TYL and estimated the pharmacodynamic effects of TYL on populations of resistant and susceptible Enterococcus within the cattle large intestine, feedlot pen, water trough, and feed bunk. The model parameters' population distributions were based on the available literature; 1000 Monte Carlo simulations were performed to estimate the likely distribution of outcomes. At the end of the simulated treatment period, the median estimated proportion of macrolide-resistant enterococci was only 1 percentage point higher within treated cattle compared with cattle not fed TYL, in part because the TYL concentrations in the large intestine were substantially lower than the enterococci minimum inhibitory concentrations. However, 25% of the simulated cattle had a >10 percentage point increase in the proportion of resistant enterococci associated with TYL administration, termed the TYL effect. The model predicts withdrawing TYL treatment and moving cattle to an antimicrobial-free terminal pen with a low prevalence of resistant environmental enterococci for as few as 6 days could reduce the TYL effect by up to 14 percentage points. Additional investigation of the importance of this subset of cattle to the overall risk of resistance transmission from feedlots will aid in the interpretation and implementation of resistance mitigation strategies.

The effect of housing environment on bone healing in a critical radius defect in New Zealand White rabbits.

In animal studies on bone healing, the effect of housing space and physical activity are seldom taken into account. Bone formation was evaluated in New Zealand White rabbits (mean ± SEM BW: 3.9 ± 0.11 kg) with a critical bone defect after 12 weeks of rehabilitation in pair-housing in 3 m2 large floor pens (Floor, n = 10) or standard single housing in 0.43 m2 cages (Cage, n = 10). In the randomised full-factorial study, a bone replica of calcium phosphate cement (CPC, n = 10) or autologous bone (AB, n = 10) was implanted in the unilateral 20 mm radius defect. Post-mortem, the oxidative capacity was measured by citrate synthase (CS) activity in M. quadriceps and the defect filling volume and density evaluated by microcomputer tomography (μ-CT). Histology sections were evaluated by subjective scoring and histomorphometry. Fourteen rabbits remained until the end of the study. Group Floor (n = 7; 3 CPC + 4 AB) had a higher CS activity and a larger bone defect filling volume and lower density by μ-CT measurements than group Cage (n = 7; 3 CPC + 4 AB). Three out of four rabbits in AB-Floor presented fusion of the defect with reorganisation of trabecular bone, whereas three of four in AB-Cage showed areas of incomplete healing. Floor rabbits had a higher score of bony fusion between the radius and ulna than Cage rabbits. There were no differences between groups in histomorphometry. The study found that a larger housing space increased physical activity and promoted bone formation.

Wider slot in pens with fully slatted rubber mat flooring for fattening bulls: Effects on animal hygiene, health and welfare

This study investigated health and welfare of 119 Swedish fattening bulls when allowing wider slots in fully slatted rubber mats pens. On arrival Light bulls (around 120 ± 28 kg at 4.7 ± 1.3 mo of age) were allotted to 6 pens with fully slatted rubber mats, of which 3 Control pens had 30 mm slot openings and 100 mm slat width and 3 Test pens had 35 mm slot openings and 90 mm slat width. Reaching >400 kg (Heavy bulls), Control bulls were moved to 3 larger pens having 35 mm slot openings and 100 mm slat width and Test bulls to 3 pens having 40 mm slot openings and 100 mm slat width. Pens hosted 5–7 bulls. Bulls stayed in the same group (Control/Test), and were observed until slaughter (around 600 kg for 20.5 ± 2.1 mo). Total drainage area was 14% for Control and 18% for Test floors. Bull body condition, hygiene, locomotion and leg lesions were assessed on eight days during the 18 months study. At slaughter, hind feet were measured, trimmed, and evaluated for claw disorders. Two pens/floor were filmed during two 14-h sessions to monitor animal activities, social interactions, and lying postures. Wider slots did not affect body condition or hygiene on farm, although 3 Control and 1 Test bulls were penalised at slaughter for poor hygiene. Light bulls were dirtier than Heavy bulls, especially on thigh/flank areas. Bulls became dirtier in winter. Percentage of bulls showing locomotor problems was generally low and not affected by wider slots (1.09 vs. 0.91% for Control and Test bulls, respectively). Test bulls showed a slight tendency to develop more swelling on hock and carpus (0.55 vs. 3.18% for Control and Test bulls, respectively). Rubber mats did not cause toe overgrowth (mean dorsal wall of outer claw = 87.5 mm) and Test bulls showed lower prevalence of asymmetric claws (38.5 vs. 13.3% for Control and Test bulls, respectively). Interdigital hyperplasia and white line fissure were detected only in Control bulls. Outcomes of this study suggested that the 4%-unit increase in drainage area of fully slatted rubber mat floors did not impair bull behaviour, since few atypical transitions and lying sequences were recorded, or even improve flooring and animal hygiene. However, some limitations of the research require further investigations to provide evidence supporting the widening of slot openings in fully slatted rubber mat floors for fattening bulls’ welfare purpose.

Effects of time-based feed restriction on morbidity, mortality, performance and meat quality of growing rabbits housed in collective systems

In rabbit farms, quantitative feed restriction in the post-weaning period is widely used with the aim of reducing the impact of digestive diseases, whereas less information is available about feed restriction strategies based on the reduction of access time to feeders in different housing systems. This study compared morbidity, mortality, growth performance, carcass characteristics and meat quality of 368 crossbred rabbits fed ad libitum (L) or subjected to a time-based feed restriction programme (R) and housed from 31 to 73 days of age in cages or pens with different dimensions and group sizes, that is, eight conventional cages (0.33 m2, six rabbits/cage), eight small open-top pens (0.50 m2, eight rabbits/pen), eight medium open-top pens (1.00 m2, 16 rabbits/pen) and four large open-top pens (2.00 m2, 32 rabbits/pen). Feed restriction was attained by progressively reducing the access time to feeders in the 1st week from 14 to 8 h/day, maintaining 8 h in the 2nd week and then by increasing access time by 1 h/day during the 3rd and 4th week up to 24 h/day. In the first 2 weeks, R rabbits showed a lower (P ≤ 0.001) daily weight gain, feed intake and feed conversion as compared with L rabbits. During the 3rd and 4th weeks, R rabbits exhibited a greater daily weight gain and better feed conversion (P ≤ 0.001). In the last 2 weeks of trial, daily weight gain tended (P = 0.06) to be greater in the R than L rabbits. In the whole trial, R rabbits manifested a lower daily weight gain, feed intake and feed conversion, as well as lower final live weight and the carcass dressing percentage at slaughter (0.05 ≤ P ≤ 0.01). During feed restriction, R rabbits did not show digestive problems, which, however, appeared in the following 2 weeks of refeeding. Thus, R rabbits had a higher health risk index in the whole trial as compared with L rabbits (P ≤ 0.05). The housing system did not affect growth performance, characteristics at slaughter, and carcass and meat quality. Mortality tended to increase with group size (P = 0.06). In conclusion, the time-based feed restriction significantly improved feed efficiency of growing rabbits housed collectively but had somewhat negative effects on characteristics at slaughter and on morbidity and mortality rate.

PSIX-21 Effect of reduced digestible protein and amino acid supply imposed in the grower and finisher period or solely in the finisher period on growth performance and feeding behaviour

Abstract Above 65 kg empty BW, protein deposition is greater in pigs fed protein-restricted compared to standard diets. It is unclear whether the greater CP deposition rate in the finisher period results from the restricted CP supply in the grower phase. To elucidate this, a growth performance study (22.1–110.0 kg BW) was performed with 48 Large-White pigs. They were assigned within litter to 3 dietary treatments: C, LP-F, LP-GF. The grower-finisher diets of treatment C were formulated based on the Swiss feeding recommendations whereas those for the LP-GF treatment contained 20% lower digestible CP and essential amino acids levels than the C diets. Pigs of the LP-GF group were offered in the grower and finisher period the standard and the low CP diets, respectively. The pigs were reared in one large pen, equipped with 6 automatic feeders, which allowed measuring the individual ad-libitum feed intake per visit. The BW was determined weekly. Growth performance and feed behaviour data were analysed with a linear mixed model using treatment as fixed and litter, litter size and farrowing series as random effects. Despite total CP intake was 6 and 16% lower (P &amp;lt; 0.05) in the LP-GF than the LP-F and C groups, respectively, overall ADG from 22.1 to 110.0 kg BW did not differ. Accordingly, gain-to-CP-intake ratio was 9 and 20% greater (P &amp;lt; 0.05) in the LP-GF than the LP-F and C group. In the grower, but not the finisher period, LP-GF pigs visited 1.6-times more (P &amp;lt; 0.05) the feeder and ingested 12% less (P &amp;lt; 0.05) feed per visit than C and LP-F pigs. These data suggest that lowering the CP supply by 20% in the grower and finisher compared to solely the finisher period or not at all has no detrimental effect on growth performance and markedly improves CP utilization for growth.

An Integrated Pest Management Tactic for Quagga Mussels: Site‐Specific Application of Fish Biological Control Agents

AbstractThe quagga mussel Dreissena bugensis is a harmful aquatic pest that invaded the southwestern USA in 2007. Challenges with managing this pest have been encountered because the invaded systems are primarily open‐water sources used for human consumption and/or are connected to freshwater habitats containing threatened and endangered species. Existing chemical and physical control methods are undesirable, and the use of some methods is restricted or prohibited because they pose risks to humans and ecosystems more broadly. To address this problem, we investigated the efficacy of using resident fishes as biocontrol agents for managing different life stages of quagga mussels on different spatial scales in a site‐specific manner. We conducted field experiments to test whether planktivorous Bluegill Lepomis macrochirus reduced mussel infestations on substrates of varying orientations in small and large pens through predation on larval mussels. We also performed an experiment to evaluate whether carnivorous Redear Sunfish L. microlophus reduced mussel infestations established on substrates of varying orientations in small pens through predation on juvenile and adult mussels. Bluegill significantly reduced mussel infestations on all substrates in the pens through predation on larvae and small juvenile mussels. Redear Sunfish reduced existing juvenile and adult mussel populations in some cases, with consumption varying among individuals and substrate orientations. Our results indicate that fishes, specifically Bluegill, may represent effective site‐specific biocontrol agents for quagga mussels, reducing impacts on targeted infrastructure (e.g., water towers, docks, and pipes) and habitats having different surface orientations by controlling more than one life stage of the pest. Development of an integrated pest management strategy that considers application of this tactic in combination with others would undoubtedly improve the management of quagga mussels—and potentially that of congeneric zebra mussels D. polymorpha—within lake and reservoir ecosystems.

Investigating the effect of pen shape and pen size on group flight distance of extensively managed ewes

This study investigated the effect of pen shape and pen size on the group flight distance of extensively managed ewes, and how flight distances of individual ewes compared when recorded in group and isolated settings. Within eight groups of 25 sheep, six focal animals were randomly selected (N = 48 ewes). Over four days, groups were placed in four different sized and shaped pens and flight distances (m) of focal animals were recorded. Pens designs were small rectangle (3.3 m x 7.2 m), medium rectangle (4.8 m x 5.8 m), large rectangle (11 m x 19.6 m) and curved/concave (with 31.5 m perimeter). Following a previously validated protocol, flight distance (m) was also recorded when focal sheep were physically isolated from conspecifics. There was no association between the isolated flight distance and group flight distance of focal animals (n = 39, r(37) = 0.03, P = 0.83).Group flight distance was significantly affected by pen design (P < 0.001), being greater in large pens and smaller in small pens. To account for these pen effects, group flight distance was adjusted and analysed as a proportion of the largest dimension of each pen. To test this mathematical adjustment, pen and other variables predicted to have an influence on adjusted group flight distance were analysed as fixed effects in linear mixed models. A statistically significant Day x Pen interaction was found (F9,84 = 3.01, P < 0.004), although post-hoc pairwise comparisons showed that this interaction had no clear pattern across days or pens. The simple mathematical adjustment and statistical modelling made group flight distances comparable by accounting for day and pen effects. These results suggest that analysing group flight distance as a proportion of the pen in future welfare assessments will enable comparisons to be made between sites.