Leg Health Research Articles

Light-dark rhythms during incubation of broiler chicken embryos and their effects on embryonic and post hatch leg bone development.

There are indications that lighting schedules applied during incubation can affect leg health at hatching and during rearing. The current experiment studied effects of lighting schedule: continuous light (24L), 12 hours of light, followed by 12 hours of darkness (12L:12D), or continuous darkness (24D) throughout incubation of broiler chicken eggs on the development and strength of leg bones, and the role of selected hormones in bone development. In the tibiatarsus and femur, growth and ossification during incubation and size and microstructure at day (D)0, D21, and D35 post hatching were measured. Plasma melatonin, growth hormone, and IGF-I were determined perinatally. Incidence of tibial dyschondroplasia, a leg pathology resulting from poor ossification at the bone’s epiphyseal plates, was determined at slaughter on D35. 24L resulted in lower embryonic ossification at embryonic day (E)13 and E14, and lower femur length, and lower tibiatarsus weight, length, cortical area, second moment of area around the minor axis, and mean cortical thickness at hatching on D0 compared to 12L:12D especially. Results were long term, with lower femur weight and tibiatarsus length, cortical and medullary area of the tibiatarsus, and second moment of area around the minor axis, and a higher incidence of tibial dyschondroplasia for 24L. Growth hormone at D0 was higher for 24D than for 12L:12D, with 24L intermediate, but plasma melatonin and IGF-I did not differ between treatments, and the role of plasma melatonin, IGF-I, and growth hormone in this process was therefore not clear. To conclude, in the current experiment, 24L during incubation of chicken eggs had a detrimental effect on embryonic leg bone development and later life leg bone strength compared to 24D and 12L:12D, while the light-dark rhythm of 12L:12D may have a stimulating effect on leg health.

Lameness and its relationship with health and production measures in broiler chickens

The aim of this study was to explore lameness and the associations between lameness and health/production measures of animal welfare in commercial broiler production, using the Welfare Quality® protocol for broilers. A total of 50 flocks were included in the sample and farm visits were conducted for lameness scoring at a mean age of 28.9 days. The percentage of animals (n=7500) in the six different gait score (GS) categories were GS0: 2.53%, GS1: 44.19%, GS2: 33.84%, GS3: 16.32%, GS4: 2.36% and GS5: 0.53%. Production and other welfare data were collected for each flock after slaughter. Higher gait scores were associated with increased hock burn score (P<0.02), increased footpad dermatitis score (P<0.01), reduced bird cleanliness score (P<0.01) and peat litter (P<0.01). Although not statistically significant, there was a tendency for increased flock gait score being associated with wet litter (P=0.07). In addition, condemnations at postmortem inspection were associated with increasing gait scores (P<0.05), indicating that at least a portion of the lameness cases display pathological changes on the carcasses. In conclusion, 19%of the birds showed moderate-to-severe lameness, which was associated with several production or health and welfare observations including feather cleanliness and condemnations as unfit for human consumption at slaughter. Although stocking density and growth rate are already known key factors for lameness, associations of lameness with hock burns, footpad dermatitis and cleanliness of the birds suggest that a suboptimal physical environment (e.g. litter- and air quality) may be detrimental to leg health. Further studies are needed to explore these associations in more detail.

Effect of wood shaving litter density on the growth, leg disorders and manurial value in broiler

&#x0D; The study was conducted with an aim to investigate the effect of litter density on growth, leg health and litter quality of broiler chickens from d1-42 days. Day-old male broiler chicks (n=400; Cobb 500) were distributed randomly into four litter densities [T1, T2, T3 and T4] treatments, each treatment had 5 replicates with 20 birds per replicate cage in a completely randomized design. Wood shaving was used as litter materials to a thickness of 5 cm, 8 cm, 11 cm and 14 cm on the floor of the pen. Birds were reared on the litter floor open-sided housing condition with ad libitum feed and water throughout the trail period. Data on feed intake (FI), body weight (BW), feed conversion ratio (FCR) and mortality were measured weekly. Litter sample was collected on day 42 to assess the nitrogen content (N2 %), dry matter (DM%) and moisture level (%). Footpad dermatitis (FPD) and hock burn (HB) incidences were measured on day 42 to assess the leg quality of birds. Results demonstrated that litter thickness had no significant (P&gt;0.05) effect on FI, BW, FCR and mortality of broilers from d1-42 days. The N2, DM or moisture levels (%) of litter were also unaffected (P&gt;0.05) between treatment. Leg disorders such as HB and FPD were influenced (P&lt;0.01) by treatment. The incidences of HB and FPD were higher (P&lt;0.01) in T1 and T2 than other treatments. It can be inferred from our current study that, leg health may be deteriorated by using low density wood shaving without affecting growth and litter quality of broiler chickens.&#x0D; Bang. J. Anim. Sci. 2018. 47 (1): 21-27&#x0D; &#x0D;

Associations between qualitative behaviour assessments and measures of leg health, fear and mortality in Norwegian broiler chicken flocks

Qualitative behavioural assessments (QBA) is an animal-based welfare measure that has been included in several on-farm welfare assessment protocols, including the Welfare Quality® (WQ) protocol for poultry. However, there is a scarcity of information about how it relates to other animal-based welfare indicators. The aim of this study was therefore to investigate the associations between QBA and selected animal-based welfare indicators commonly used for the assessment of broiler chicken welfare, i.e. lameness, foot pad dermatitis (FPD), fear of humans (touch test), and mortality.A total of 50 commercial broiler chicken farms were visited by one observer who conducted on-farm welfare assessments using the WQ protocol. Assessments were done close to the time of slaughter (between day 27 and 34). QBA was analysed using principal component analysis (PCA), revealing two main components, labelled arousal (PC1) and mood (PC2). The scores for the other welfare indicators were categorised into dichotomous (touch test) or ordinal scales (gait score, footpad dermatitis score and mortality) to deal with skewed distributions caused by homogenous data. To investigate the associations between QBA and the other welfare indicators, we ran logistic and ordinal logistic regression models with these welfare measures as outcomes, and the two components of QBA as the predictors.Significant negative associations were found between both components of QBA and the chickens’ fear of humans, as measured using the touch test. In other words, flocks with higher scores on both mood and arousal were less likely to have any chickens that were possible to touch by the assessor. A possible interpretation of these associations is that both QBA components may indicate greater liveliness in birds that did not accept to be touched by the observer. Flocks with a higher arousal score, as measured by the first component of QBA (PC1), were also less likely to be in a higher mortality category. For the other selected animal-based measures, there were no associations with QBA. We conclude that QBA needs thorough validation for the routine use in the assessment of broiler chicken welfare, but that the method may provide useful supplementary information in overall welfare assessments. This information may be particularly valuable in a production system, like the broiler industry, where management is highly standardised, sometimes resulting in little between-flock variation in other welfare measures.

Effects of lighting, stocking density, and access to perches on leg health variables as welfare indicators in broiler chickens

An experiment was conducted to investigate the effects of lighting program, stocking density, and the provision of a perch on leg health variables as welfare indicators in broiler chickens. A total of 360 mixed sex Ross 308 1-D-old broiler chickens (180 male and 180 female) were placed in a completely randomized design with 2 × 2 × 2 factorial arrangement of lighting program (continuous or restricted), stocking density (12 or 18 birds/m2), and the provision of a perch (perch or without perch). At d 42, tibial dyschondroplasia (TD), valgus-varus deformity (VVD), footpad dermatitis (FPD), and hock burn (HB) were scored. In addition, tibio-tarsal index, robusticity index, bone weight-length index, tibia crude ash content, and fluctuating asymmetry (FA) and relative fluctuating asymmetry (rFA) of tibia width and length were measured. The incidence of TD increased in broiler chickens subjected to continuous lighting (P < 0.05) in comparison with those subjected to restricted lighting. Presence of a perch reduced the incidence and severity of FPD (P < 0.01) compared to without a perch. Restricted lighting tended (P = 0.093) to decrease the incidence and severity of HB lesions. The broiler chickens placed at low stocking density (12 birds/m2) and with access to a perch had lower incidence and severity of HB lesions (P < 0.01 and P < 0.001, respectively) compared to their corresponding opposite groups. Tibio-tarsal index was greater (P < 0.01) in broiler chickens subjected to restricted lighting regimen compared to continuous lighting whereas the provision of a perch tended to increase (P = 0.081) the tibio-tarsal index in broiler chickens compared to those without perch. There was a tendency of decreasing tibia crude ash content with increasing stocking density from 12 to 18 birds/m2 (P = 0.056). However, birds without perches had greater (P < 0.01) tibia crude ash content compared those with a perch provided. Continuous lighting increased the FA and rFA of tibia length in comparison with restricted lighting program (P < 0.05) in broiler chickens. In conclusion, it can be said that restricted lighting programs and provision of perches may help reduce the leg health problems thus contributing to improved welfare in broiler chickens.

Neural predictive control of broiler chicken and pig growth

Active control of the growth of broiler chickens and pigs has potential benefits for farmers in terms of improved production efficiency, as well as for animal welfare in terms of improved leg health in broiler chickens. In this work, a differential recurrent neural network (DRNN) was identified from experimental data to represent animal growth using a nonlinear system identification algorithm. The DRNN model was then used as the internal model for nonlinear model predictive control (NMPC) to achieve a group of desired growth curves. The experimental results demonstrated that the DRNN model captured the underlying dynamics of the broiler and pig growth process reasonably well. The DRNN based NMPC was able to specify feed intakes in real time so that the broiler and pig weights accurately followed the desired growth curves ranging from −12% to +12% and −20% to +20% of the standard curve for broiler chickens and pigs, respectively. The overall mean relative error between the desired and achieved broiler or pig weight was 1.8% for the period from day 12 to day 51 and 10.5% for the period from week 5 to week 21, respectively.

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

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

Ranging behavior relates to welfare indicators pre- and post-range access in commercial free-range broilers.

Little is known about the effect of accessing an outdoor range on chicken welfare. We tracked individual ranging behavior of 538 mixed-sex Ross 308 chickens on a commercial farm across 4 flocks in winter and summer. Before range access, at 17 to 19 d of age, and post-range access, at 30 to 33 and 42 to 46 d of age in winter and summer flocks respectively, welfare indicators were measured on chickens (pre-range: winter N = 292; summer N = 280; post-range: winter N = 131; summer N = 140), including weight, gait score, dermatitis and plumage condition. Post-ranging autopsies were performed (winter: N = 170; summer: N = 60) to assess breast burn, leg health, and ascites. Fewer chickens accessed the range in winter flocks (32.5%) than summer flocks (82.1%). Few relationships between welfare and ranging were identified in winter, likely due to minimal ranging and the earlier age of post-ranging data collection compared to summer flocks. In summer flocks prior to range access, chickens that accessed the range weighed 4.9% less (P = 0.03) than chickens that did not access the range. Pre-ranging weight, gait score, and overall plumage cover predicted the amount of range use by ranging chickens in summer flocks (P < 0.01), but it explained less than 5% of the variation, suggesting other factors are associated with ranging behavior. In summer flocks post-range access, ranging chickens weighed 12.8% less than non-ranging chickens (P < 0.001). More range visits were associated with lower weight (P < 0.01), improved gait scores (P = 0.02), greater breast plumage cover (P = 0.02), lower ascites index (P = 0.01), and less pericardial fluid (P = 0.04). More time spent on the range was associated with lower weight (P < 0.01) and better gait scores (P < 0.01). These results suggest that accessing an outdoor range in summer is partly related to changes in broiler chicken welfare. Further investigations are required to determine causation.

Welfare assessment of conventional and organic broilers in Denmark, with emphasis on leg health

The aim of this study was to survey and report the walking ability in broilers housed in both conventional and organic production systems in Denmark. To this end, the authors...

The relationship between measures of fear of humans and lameness in broiler chicken flocks

In the Welfare Quality® assessment protocol for broilers, the touch test is included to assess the human–animal relationship in the flock. The test is designed to measure the animals’ fear of humans, assuming that broilers will withdraw from the observer if they are fearful. However, many broilers close to slaughter age have impaired walking ability, and the results from the touch test may thus be biased by lameness and poor leg health. As the touch test is currently being used in several countries to assess human–animal relationship in broilers, there is an urgent need to examine this potential relationship for a further validation of the test. In the present study, fear of humans was assessed in 50 randomly selected Norwegian broiler flocks, using the touch test as described in the Welfare Quality® protocol for ty broilers. Leg health was assessed by examining the gait of 150 random birds in each of the flocks, using a six-point gait score scale from 0 to 5. The coefficient for the relationship between touch test score and gait score was 0.034 (P<0.001), indicating that the animals express less fear as assessed by the touch test when the gait scores increase. This implies that the touch test may be confounded by impaired walking ability and therefore might be a suboptimal method of assessing fear of humans and human–animal relationship in broilers. In conclusion, the results from this study suggests that the touch test must be further validated in broilers and perhaps be replaced with a fear test that doesn’t rely on walking ability.

Effect of rubber mats and perforation in the lying area on claw and limb lesions of fattening pigs

Claw and leg lesions are frequently observed in finishing pigs and are likely to compromise their welfare. Providing softer than the usual concrete flooring may reduce both the frequency and severity of these lesions. Therefore, this study evaluated the influence of rubber mats and floor perforation in the lying area on claw and leg health of finishing pigs. A total of 240 Swiss Large White finishing pigs from on average 24.9 kg until 102.3 kg were used in four batches, with six groups of 10 animals per batch. The six experimental pens initially measured 1.85×3.55 m and were enlarged after 6 weeks to 1.85×5.25 m. In all pens, one third of the floor space was built as a defecating area consisting of a concrete floor with 15% perforation. The remaining two thirds of the pen were designed as a lying area whose floor quality differed between the pens. It either consisted of concrete elements or was covered with rubber mats, and perforation of both floor types was either 0%, 5% or 10%. All individuals were scored for claw and leg lesions at the beginning, in the middle and at the end of the 12-week fattening period. Lesions were summarised in scores based on the results of a principal component analysis. The influence on lesion scores of floor material, amount of perforation in the lying area, assessment time, and sex was examined using mixed-models. The total claw lesion score and the total limb lesion score as well as the claw angle increased from the beginning to the end of the fattening period. The values for both scores were slightly lower for animals kept on rubber mats compared with animals kept on concrete floor. There was no effect of the percentage of perforation on the examined outcome variables. In conclusion, our results indicate that rubber mats in the lying area bring about improvements in some aspects of claw and leg health in fattening pigs, whereas there is no effect of floor perforation.

Exploring perch provision options for commercial broiler chickens

Two related experiments involving broiler chickens are presented. Experiment 1 evaluated the use of six perch types: (1) an A-frame design (incorporating a platform and ramps), (2) a ‘flat top’ ramp, (3) a curved ramp, (4) a suspended bar, (5) a fixed bar and (6) a suspended platform. Two of each perch type was provided in one commercial house on each of two farms over two 6-week production cycles. Each perch was videoed for a 24 h period in weeks 1–6 of cycle 1, and weeks 1–5 of cycle 2. Scan sampling was used to assign an occupancy score to different perch components (platform, bar and ramp, where appropriate), and an overall weighted occupancy score also calculated. Counts were made of perching and failed perching attempts following selected scans in cycle 1. There were significantly higher occupancy scores for platform than for bar or ramp components, and this was apparent across the production cycle. This resulted in a higher overall weighted occupancy score for suspended platforms. The percentage of failed perching attempts was significantly greater with fixed and suspended bar perches than with the curved ramp. Three treatments were assessed in Experiment 2: (1) provision of six suspended platform perches (P), (2) provision of six suspended platform perches and four peat-filled dust baths (PD), and (3) control treatment with no platform perches or dust baths. Treatments were applied in one of three houses on each of two farms, and replicated over three cycles. Two perches in each of the P and PD treatments were videoed for a 25 min period in weeks 3, 4 and 5, and number of birds using the perches recorded. The severity of angular leg deformities, hock burn and pododermatitis lesions, and walking ability were scored in weeks 3, 4 and 5, and prevalence of pododermatitis and hock burn recorded at slaughter. Litter moisture and production-related measures were also taken. On average, 26 birds (12.6 birds/m2) occupied the perches, and this was not affected by provision of dust baths or age. Treatment did not significantly affect any of the measures taken. It is concluded that broilers prefer to perch on platforms rather than bars or ramps, and thus that platforms better cater for an important behavioural need. However, provision of platform perches, even in combination with dust baths, did not improve leg health, and future research should investigate greater levels of provision of these enrichments.

Evaluation of a dustbathing substrate and straw bales as environmental enrichments in commercial broiler housing

The use of straw bales as an environmental enrichment is common for broiler chickens in enriched housing systems, however relatively little information exists about their effectiveness in improving welfare. There has also been no widespread introduction of a dustbathing material for broilers. The main aim of this trial was to evaluate the use of a dustbathing substrate (in the form of oat hulls), both as an alternative to straw bales and as a supplementary enrichment. Over four replicates, four commercial houses, each containing approximately 22,000 broilers, were assigned to one of four treatments over the 6-week production cycle: (1) straw bales (B; one per 155m2), (2) oat hulls as a dustbathing substrate (OH; provided in 1m diameter steel rings, one per 155m2), (3) both oat hulls and straw bales (OH+B), and (4) a control treatment with no environmental enrichment (C). Observations of broiler behaviour and leg health were taken weekly, and performance data was collected for each cycle. Broilers housed in the OH and OH+B treatments had better gait scores in week 6 than those housed in the C treatment (P<0.05), which suggests that the provision of oat hulls improved bird leg health. However, there was no associated increase in activity levels in unenriched areas of the houses. Conversely, more locomotion (P<0.001), less sitting inactive (P<0.001) and less sitting pecking (P<0.001) were observed in the C treatment than in unenriched areas of B, OH and OH+B treatments. More birds were recorded around the bales compared to the oat hulls (P<0.001), however birds performed significantly more foraging (P=0.019) and dustbathing (P=0.045) in oat hulls than around straw bales. Although oat hulls appear to be more suitable for stimulating active behaviours than straw bales, the high level of resting recorded around the bales suggests they may have a positive function as protective cover. The presence of an additional type of enrichment in the house did not affect the number of birds, or the type of behaviours performed in close proximity to either straw bales or oat hulls (P>0.05). Treatment did not have a significant effect on pododermatitis levels or slaughter weight, on mortality rates, or on litter quality or atmospheric ammonia levels (P>0.05). Overall, our results suggest that the oat hulls substrate was a successful enrichment in terms of promoting dustbathing and foraging, and improving bird leg health. The straw bales also appeared attractive to the birds, however, which suggests that a dustbathing substrate should be a supplementary enrichment.

High stocking density alters bone-related calcium and phosphorus metabolism by changing intestinal absorption in broiler chickens.

Live performance, bone health and metabolic responses to the interaction among stocking density and dietary concentrations of total calcium (TCa) and non-phytate phosphorus (NPP) were determined on 2,232 Ross 308 female broilers over a 3-wk experimental period. From 22 d of age, birds were randomly divided into 48 groups and provided with different corn-soybean meal-based diets varying in TCa (0.70% or 0.90%) and NPP (0.28% or 0.36%) content at 1 of 2 stocking densities [28.6 (LSD, 13 broilers/m2) and 39.6 (HSD, 18 broilers/m2) kg of predicted final BW/m2 floor space], according to a 2 × 2 × 2 factorial design with 6 replications in each treatment. Regardless of NPP supplementation, a high-TCa (0.90%) diet aggravated the impact of HSD on growth (BW gain and feed efficiency, P <0.001) and motility (gait score, P <0.001). This might be explained by deteriorating tibia quality (relative weight, mineral composition and biomechanical property; P <0.01), due to the involvement of decreasing duodenal absorption (type IIb sodium-phosphate co-transporter mRNA, P <0.001) in reduced phosphorus retention (P <0.001). On the contrary, increasing dietary NPP (0.36%), particularly if high in TCa (0.90%), boosted TCa retention (P <0.05) by improving absorption (calcium-binding protein D28k transcription, P <0.05) for LSD chickens, hence enhancing bone development (relative tibia weight and tibia breaking strength, P <0.05) and leg health (walking ability, P <0.05). Together, HSD and LSD birds show an impaired TCa tolerance and a higher TCa+NPP threshold, respectively, to allow the optimization of bone quality via altered intestinal absorption.

An automated positioning system for monitoring chickens’ location: Effects of wearing a backpack on behaviour, leg health and production

Automated tracking of the location of individual chickens is becoming more common in behavioural research. This technology has several advantages including gathering large amounts of data and monitoring of individual animals as opposed to flocks. To ensure the quality of the research the transmitters or tags attached to the bird as part of the automated positioning system should not have any effect on bird behaviour, welfare and production. Tag-related effects may lead to unreliable results which cannot be extrapolated to untagged birds. Therefore, we tested the effects of wearing a backpack containing a tag as part of an ultra-wideband system for automated position monitoring. The chickens’ behaviour, leg health, cleanliness and body weight gain were studied. Sixty slow-growing broiler chickens (Sasso XL451) were housed in groups of 10 birds. Per pen, five birds were fitted with a 36-g tag (TAG) in a backpack from day 35–70 and the other five were identified using colour markings (CON). Behavioural observations from video recordings of TAG and CON chickens were performed twice daily (15-min periods) every other day. Birds were weighed on day 35 and 70, and on day 70 foot pad and hock dermatitis, gait, and cleanliness were scored. TAG birds walked less than CON birds in week 6, but this difference was absent from week 7 onwards. CON birds pecked more at TAG birds than other TAG birds did in week 6, probably due to the novelty of the tags, whereas the TAG birds could investigate their own tag instead of pecking at other birds’ tags. No significant differences were observed for scores for foot pad and hock dermatitis, gait and cleanliness scores or weight gain between TAG and CON birds. These results indicate that the backpacks with tags had only minor, non-persistent effects on slow-growing broiler chickens’ behaviour. The effects of colour-marking on behaviours observed in this study are likely to be small. The results indicate that the tags can be used for further studies in which these behaviours, welfare measures and production parameters play an important role.

Incubation lighting schedules and their interaction with matched or mismatched post hatch lighting schedules: Effects on broiler bone development and leg health at slaughter age

The incidence of leg pathologies in broiler chickens with a developmental origin may be decreased by stimulating embryonic bone development through lighting schedules during incubation, but this may depend on post hatch lighting conditions. Aim was to investigate how lighting schedules during incubation and their interactions with matched or mismatched lighting schedules post hatch affected bone development and leg health at slaughter age. In a 3×2 factorial designed experiment, eggs were incubated under continuous cool white LED light (Inc24L), 16h of light, 8h of darkness (Inc16L:8D), or continuous darkness (Inc24D) from set till hatch. After hatch, broilers were housed under continuous light (PH24L, to match Inc24L and Inc24D) or 16h of light, 8h of darkness (PH16L:8D, to match Inc16L:8D). Gait scores were determined on D21, D28, and D34. After slaughter on D35, legs were scored for varus-valgus deformities, rotated tibia, tibial dyschondroplasia, bacterial chondronecrosis with osteomyelitis (BCO), epiphyseolysis, and epiphyseal plate abnormalities from 1=absent to 4=severe. Femur and tibia dimensions and mineral density were determined. Inc24L led to more epiphyseal plate abnormalities than Inc16L:8D or Inc24D. Inc24D led to more BCO than Inc16L:8D. Gait scores on D21, D28, and D34, and bone dimensions did not differ between treatments. Inc24L led to higher femur mineral density than Inc24D with Inc16L:8D intermediate. Providing a chicken with a matched post hatch lighting schedule did not affect most measurements of bone development and health. It can be concluded that a circadian incubation lighting schedule may improve leg health in broilers.

Gait parameters in four strains of turkeys and correlations with bone strength

Locomotion problems in meat poultry have multifactorial etiology. A better understanding of normal gait and its influences on biomechanical aspects of leg bones among turkey genetic lines is important to prevent skeletal disorders and locomotion issues. The objective of this experiment was to determine the possible differences in gait kinetic and kinematic parameters of turkey strains and their effects on bone biomechanical properties. Four genetic lines, named A, B, C, and D, were obtained and raised in 48 floor pens with new pine shavings. Leg health issues were classified at 16 and 33 d of age. Fifteen turkeys from each strain with apparent normal legs and gait at 33 d of age were selected for gait analysis. These 15 turkeys were trained to walk on a pressure sensitive walkway and video was recorded to calculate articulation movements. These data also were analyzed to obtain kinetic and kinematic parameters of the gait cycle collected at 47, 84, 107, and 145 d of age. At 20 wk all turkeys were sacrificed, and legs were collected and frozen for analysis. Weights and morphologic measurements of the femur, tibia, and shank were recorded. Bone mineral density (BMD) and content (BMC) were obtained using DEXA. Femur and tibia strength were evaluated by a 4-point bending test and torsion test, respectively. Gait parameters changed as toms aged and some differences were observed among lines. Genetic lines differed on BMD, but not on BMC. Strain D had a higher BMD and smaller diaphyseal angle than strain C, characteristics that were correlated with stronger bones. Strain D also had the lowest incidence of leg problems while strain C had the highest. Furthermore, the D strain had a smaller vertical motion of the toe than strains C and B at 47 d and strain A at 145 d, indicating that the D strain had a more efficient gait. In summary, genetic strains differ significantly on gait parameters, which in turn impacts bone biomechanics.

DEPRESSION IN COMMUNITY-LIVING OLDER ADULTS WITH CHRONIC VENOUS LEG ULCERS

Older adults are at higher risk of developing venous leg ulcers, many of which do not heal for months or years. Qualitative reports suggest the chronic condition is associated with poor self-esteem, anxiety and depression; however, there is little information on the prevalence of depressive symptoms, or factors associated with them. Data were collected for 24 weeks from a sample of 386 community-living adults with venous leg ulcers, on socio-demographics, health, and symptoms, utilising the Geriatric Depression Scale (GDS) for depressive symptoms. Multivariable linear regression identified factors associated with depressive symptoms, and logistic regression identified predictors of failure to heal within 24 weeks. The mean age was 79 years (SD 14.4) and 52% were female. On enrolment, 8% (n=29) of participants scored at high risk of depression, and another 23% (n=92) scored at mild risk of depression. Controlling for gender and co-morbidities, regression analysis found younger age (p=0.012), pain (p=0.017) and poorer social support (p=0.001) were significantly associated with higher GDS scores. Higher GDS scores were significantly associated with failure to heal after 24 weeks at the bivariate level (p=0.031), however regression analysis found living alone (OR 2.33, 95%CI 1.37–3.94), rheumatoid arthritis (OR 2.94, 95%CI 1.33–6.67) and weeks of ulcer duration (OR 1.01, 95%CI 1.005–1.014) were the primary predictors of failure to heal (p<0.01). Results suggest that depressive symptoms may not be directly involved in chronic wound healing, rather social factors and management of comorbidities may be significant factors to address to promote well-being and ulcer healing.

Genetic basis of leg health and its relationship with body weight in purebred turkey lines

The aims of this study were to estimate the genetic parameters for leg and foot health and mobility in purebred turkey lines and their genetic correlations with BW. Traits were gait score (GS) as an overall measure of leg health, footpad dermatitis (FPD), and 2 skeletal leg health traits, namely, valgus and varus deformities (VVD) and tibial dyschondroplasia (TD). Data from 4 different lines, comprising 3 yr of phenotypic records and 4 yr of pedigree information per line, were used. The sex average BW for the lines at 18 wk ranged from 19.1 kg (line A) to 12.4 kg (line D). The prevalence of VVD ranged from 5.2 to 14.6% and for TD from 4.1 to 23.2%. The average score for FPD on a scale of 0 to 100 ranged from 48.5 to 61.1. Gait Score was scored on a scale of 1 to 5, standardized to a mean of 3 and SD of 1. Heritabilities were estimated at 0.08 to 0.13 for GS, 0.01 to 0.07 for VVD, 0.06 to 0.12 for TD, and 0.10 to 0.15 for FPD (all SE ≤ 0.02). Estimates of the genetic correlations between VVD and TD ranged from 0.03 to 0.21 (all SE ≤ 0.08), and estimates of these with GS ranged from 0.07 to 0.87 (all SE ≤ 0.09). The genetic correlations of FPD with GS ranged from 0.00 to 0.34 (all SE ≤ 0.04), and with the skeletal leg health traits from -0.06 to 0.33 (all SE ≤ 0.06). Body weight showed estimated genetic correlations ranging from 0.28 to 0.51 (all SE ≤ 0.06) with GS, -0.06 to 0.50 (all SE ≤ 0.13) with VVD/TD and 0.05 to 0.34 (all SE ≤ 0.05) with FPD. The results suggest that selection for improved leg health can be incorporated effectively in a commercial turkey breeding program using balanced breeding goals, in which production traits and leg health traits are considered simultaneously.

Integrating an automated activity monitor into an artificial insemination program and the associated risk factors affecting reproductive performance of dairy cows

The aim of this study was to compare 2 reproductive programs for the management of first postpartum artificial insemination (AI) based on activity monitors and timed AI, as well as to determine the effect of health-related factors on detection and expression of estrus. Lactating Holstein cows (n = 918) from 2 commercial farms were enrolled. Estrous cycles of all cows were presynchronized with 2 injections of PGF2α administered 2 wk apart. Treatments were (1) first insemination performed by timed AI (TAI) and (2) first insemination based upon the detection of estrus by activity monitors (ACT; Heatime, SCR Engineering, Netanya, Israel) after the presynchronization, whereas cows not inseminated by the detection of estrus were enrolled in the Ovsynch protocol. Body condition score (BCS; scale 1 to 5), hock score (scale: 1 to 4), gait score (scale: 1 to 4), and corpus luteum presence detected by ovarian ultrasonography were recorded twice during the presynchronization. On the ACT treatment, 50.5% of cows were inseminated based on detected estrus, whereas 83.2% of the cows on the TAI treatment were inseminated appropriately after the timed AI protocol. Pregnancy per AI did not differ by treatment (30.8 vs. 33.5% for ACT and TAI, respectively). Success of pregnancy was affected by parity, cyclicity, BCS, milk production, and a tendency for leg health. In addition, treatment × cyclicity and treatment × parity interactions were found to affect pregnancy success, where anovulatory cows and older cows had compromised pregnancy outcomes on the ACT treatment but not on the TAI treatment. Factors affecting pregnancy outcomes varied among farms. Hazard of pregnancy by 300 DIM was affected by farm, parity, BCS, a treatment × cyclicity interaction, and a tendency for an interaction between leg health and farm. Detection of estrus was affected by farm, parity, cyclicity, and leg health, but not BCS or milk production. Expression of estrus was compromised in anovular and older cows, and by the timing of the estrus event, but not by gait score, BCS, or milk production. Increased duration of estrus, but not intensity of estrus, improved pregnancy per AI. In conclusion, using an automated activity monitor for the detection of estrus within a Presynch-Ovsynch program resulted in similar pregnancy per AI and days open compared with a reproduction program that was strictly based on timed AI for first postpartum AI. In contrast, notable variations in reproductive outcomes were detected between farms, suggesting that the use of automated activity monitors is prone to individual farm management.