A comparison of post-mortem findings in broilers dead-on-farm and broilers dead-on-arrival at the abattoir.

Broiler mortality during transport to abattoirs (dead-on-arrival/DOA) evokes concern due to compromised animal welfare and associated economic losses. The general aim of this study was to characterize pathological lesions associated with mortality in broilers close to slaughter. The specific aim was to investigate whether disease at the end of the growth period may be a predisposing factor for DOA by describing and comparing the pathological findings in broilers dead-on-farm (DOF) in the final days of the production cycle and in broilers DOA from the same flocks. Gross post-mortem examinations were performed on 607 broilers from 32 flocks, either DOF (371) or DOA (236). In DOF broilers, the most common pathological lesions were lung congestion (37.7%), endocarditis (29.4%), and ascites (24.0%), whereas the most common findings in broilers DOA were lung congestion (57.2%) and trauma (24.6%). Lung congestion was more prevalent among DOA broilers compared to DOF broilers (P-value of > 0.001). A possible cause behind the pathological finding lung congestion is sudden death syndrome (SDS). The study indicates that steps in the transportation process per se cause the majority of pathological lesions such as lung congestion and trauma that may have led to the mortalities registered. Pre-existing diseases such as ascites and osteomyelitis may also predispose for DOA. Thus, factors relating to on-farm health, catching, and transportation are all areas of future investigation in order to reduce transport mortalities and to enhance welfare in broilers.

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.

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.

Comparison of flock characteristics, journey duration and pathology between flocks with a normal and a high percentage of broilers 'dead-on-arrival' at abattoirs.

This study investigated high mortality in broilers transported to slaughter in Norway by comparing data from flocks with normal and high mortality during transportation. The data sources consisted of necropsy findings in 535 broilers dead-on-arrival (DOA), production data and slaughterhouse data, along with average journey duration for the 61 associated flocks. The mean Norwegian DOA% for 2015 was 0.10. In this study, normal-mortality flocks were defined as flocks with a mean DOA% up to 0.30 and high mortality as flocks with a mean DOA% above 0.30. DOA% was calculated per flock. The most frequent pathological finding was lung congestion which was observed in 75.5% of the DOA broilers. This postmortem finding was significantly more common in broilers from high-mortality flocks (89.3%) than in DOA broilers from normal-mortality flocks (58%). The following variables had a significantly (P<0.05) higher median in the high-mortality flocks: flock size, 1st week mortality, foot pad lesion score, carcass rejection numbers and journey duration. The results indicate that high broiler mortality during transportation to the abattoir may be linked to several steps in the broiler production chain. The results suggest that preventive measures are to be considered in improvement of health and environmental factors during the production period and throughout the journey duration.

Associations among gait score, production data, abattoir registrations, and postmortem tibia measurements in broiler chickens.

Lameness and impaired walking ability in rapidly growing meat-type broiler chickens are major welfare issues that cause economic losses. This study analyzed the prevalence of impaired walking and its associations with production data, abattoir registrations, and postmortem tibia measurements in Norwegian broiler chickens. Gait score (GS) was used to assess walking ability in 59 different commercial broiler flocks (Ross 308) close to the slaughter d, 5,900 broilers in total, in 3 different geographical regions. In each flock, 100 arbitrary broilers were gait scored and 10 random broilers were culled to harvest tibias. Abattoir registrations on flock level were collected after slaughter. A total of 24.6% of the broilers had moderate to severe gait impairment. The broilers were sampled in 2 stages, first slaughterhouse/region, and then owner/flock. The final models showed that impaired gait is associated with first-week mortality (P < 0.05), region (P < 0.001), height of tibias mid-shaft (P < 0.05), and calcium content in the tibia ash (P < 0.05), and negatively associated with DOA (P < 0.05). The prevalence of impaired gait indicates that this is a common problem in the broiler industry in Norway, although the mean slaughter age is only 31 d and the maximum allowed animal density is relatively low. Impaired walking ability could not be predicted by the welfare indicators footpad lesion score, total on-farm mortality, and decreasing DOA prevalence. Further studies are needed to explore the relationship between first-week mortality and gait score.

Early neonatal lamb mortality: postmortem findings.

An investigation of stillbirth and early neonatal lamb mortality was conducted in sheep flocks in Norway. Knowledge of actual causes of death are important to aid the interpretation of results obtained during studies assessing the risk factors for lamb mortality, and when tailoring preventive measures at the flock, ewe and individual lamb level. This paper reports on the postmortem findings in 270 liveborn lambs that died during the first 5 days after birth. The lambs were from 17 flocks in six counties. A total of 27% died within 3 h after birth, 41% within 24 h and 80% within 2 days. Most lambs (62%) were from triplet or higher order litters. In 81% of twin and larger litters, only one lamb died. The most frequently identified cause of neonatal death was infectious disease (n=97, 36%); 48% (n=47) of these died from septicaemia, 25% (n=24) from pneumonia, 22% (n=21) from gastrointestinal infections and 5% (n=5) from other infections. Escherichia coli accounted for 65% of the septicaemic cases, and were the most common causal agent obtained from all cases of infection (41%). In total, 14% of neonatal deaths resulted from infection by this bacterium. Traumatic lesions were the primary cause of death in 20% (n=53) of the lambs. A total of 46% of these died within 3 h after birth and 66% within 24 h. Severe congenital malformations were found in 10% (n=27) of the lambs, whereas starvation with no concurrent lesions was the cause of death in 6% (n=17). In 16% (n=43) of the lambs, no specific cause of death was identified, lambs from triplet and higher order litters being overrepresented among these cases. In this study, the main causes of neonatal lamb mortality were infection and traumatic lesions. Most neonatal deaths occurred shortly after birth, suggesting that events related to lambing and the immediate post-lambing period are critical for lamb survival.