Prevalence of leg weakness in broiler chickens and its relationship with genotype

110

Lameness is one of the most important dairy cow welfare issues and has inspired a growing body of literature on gait assessment. Validation studies have shown that several methods of gait assessment are able to successfully distinguish cows with and without painful pathologies. While subjective methods provide an immediate, on-site assessment and require no technical equipment, they show variation in observer reliability. On the other hand, objective methods of gait assessment provide accurate and reliable data, but typically require sophisticated technology, limiting their use on farms. In this critical review, we evaluate gait assessment methods, discuss the reliability and validity of measures used to date, and point to areas where new research is needed. We show how gait can be affected by hoof and leg pathologies, treatment of these ailments and the pain associated with lameness. We also discuss how cow (e.g. conformation, size and udder fill) and environmental features (e.g. flooring) contribute to variation in the way cows walk. An understanding of all these factors is important to avoid misclassifying of cows and confounding comparisons between herds.

Section: Subjective Methods Of Gait Assessmentmentioning

confidence: 99%

Gait assessment in dairy cattle

Flower

Weary

2009

110

“…The sum of the number of birds eating and drinking was used as the indicator of feeding activity. Walking ability was evaluated at day 30 and day 41 using the gait scoring system developed by Kestin et al (1992). Briefly, four birds in each pen were randomly selected by two observers by mutual agreement.…”

Section: Methodsmentioning

confidence: 99%

Combined effect of divergent selection for breast muscle ultimate pH and dietary amino acids on chicken performance, physical activity and meat quality

Alnahhas¹,

Berri²,

Chabault-Dhuit³

et al. 2017

Responses to changes in dietary Lys and other essential amino acid (AA) concentrations were evaluated in 480 male and female broilers originating from two lines divergently selected for high (pHu+) or low (pHu−) ultimate pH (pHu) of breast muscle. The two genetic lines were fed with two grower isoenergetic diets differing in both true digestible Lys (control = 10.2 g/kg and experimental = 7.0 g/kg) and amounts of other essential AA calculated in relation to Lys, which were sufficient for the control diet or in excess for the experimental diet. There were six repetitions per treatment. Birds were weighed individually at days 0, 21, 28 and 43. Feed consumption was recorded per pen and feed conversion was calculated over the growing period. The physical activity and walking ability of broilers were recorded during the whole rearing period. Breast and leg yield, and abdominal fat percentage were measured at 43 days of age, as were pHu, color, drip and cooking loss, Warner-Bratzler shear force, and curing-cooking yield of the breast Pectoralis major and pHu of the thigh Sartorius muscle. Divergent selection greatly affected most breast meat quality traits without significantly changing growth rate or feed efficiency. When subjected to a variation in dietary intake of AA, birds from the two genotypes responded in a similar way in terms of animal's growth, feed efficiency, body composition and meat quality traits. Although line and diet did not affect physical or feeding activities of the broilers, a significant effect of line-by-diet interaction was observed on gait score. Contrary to the pHu− birds, the walking ability of pHu+ birds was impaired when fed the control diet that favored growth and breast muscle development and limited storage of carbohydrate in muscle.

“…Sherwin et al, 1999;Bailie et al, 2013) in order to limit stress associated with bird handling and removal from house. Gait was scored on a scale of 0 to 5 where 0 = normal movement and 5 = unable to walk (Kestin et al, 1992). No birds with a gait score of 5 were recorded during the trial.…”

Section: Measurementsmentioning

confidence: 99%

The effect of level of straw bale provision on the behaviour and leg health of commercial broiler chickens

Bailie

O’Connell

2014

This study aimed to assess the effect of the number of straw bales (SBs) provided on the behaviour and leg health of commercial broiler chickens. Houses containing~23 000 broiler chickens were assigned to one of two treatments: (1) access to 30 SBs per house, '30SB' or (2) access to 45 SB per house, '45SB'. This equated to bale densities of 1 bale/44 m 2 and 1 bale/29 m 2 of floor space within houses, respectively. Treatments were applied in one of two houses on a commercial farm, and were replicated over six production cycles. Both houses had windows and were also artificially lit. Behaviour was observed in weeks 3 to5 of the cycle. This involved observations of general behaviour and activity, gait scores (0: perfect to 5: unable to walk) and latency to lie (measured in seconds from when a bird had been encouraged to stand). Production performance and environmental parameters were also measured. SB density had no significant effect on activity levels ( P > 0.05) or walking ability ( P > 0.05). However, the average latency to lie was greater in 30SB birds compared with 45SB birds ( P < 0.05). The incidence of hock burn and podo dermatitis, average BW at slaughter and levels of mortality and culling were unaffected by SB density ( P > 0.05). The results from this study suggest that increasing SB levels from 1 bale/44 m 2 to 1 bale/29 m 2 floor space does not lead to significant improvements in the welfare of commercial broiler chickens in windowed houses.Keywords: behaviour, broiler chicken, leg health, straw bales, enrichment ImplicationsThis study provides novel information on the effect of increasing the level of straw bale provision on welfare-related parameters in commercial broiler chickens. While levels may be stipulated in quality assurance schemes, there appears to be very little published research in this area. The results of this study suggest that increasing the number of straw bales provided in a standard windowed broiler house from 30 to 45 (or from 1 bale/44 m 2 to 1 bale/29 m 2 floor space) does not lead to significant improvements in welfare. This highlights the requirement for further research to determine the optimum level of provision of enrichment stimuli to maximize the welfare of birds within large commercial flocks.