Factors influencing bruises and mortality of broilers during catching, transport, and lairage

A multilevel analysis was performed to identify and quantify risk factors associated with mortality and bruises occurring between catching and slaughter of broiler flocks. The effect of each factor in the final model was expressed as an odds ratio (OR). Data included 1,907 Dutch and German broiler flocks slaughtered in 2000 and 2001 at a Dutch processing plant. The mean dead on arrival (DOA) percentage was 0.46. Percentage of bruises was corrected for economic value. The mean corrected bruises percentage was 2.20. Factors associated with corrected bruises percentage were season, moment of transport, and ambient temperature. Unfortunately, these factors are quite difficult to manipulate. Factors associated with DOA percentage were ambient temperature, moment of transport, catching company, breed, flock size, mean BW, mean compartment stocking density, transport time, lairage time, and the interaction term transport time x ambient temperature. The most important factors that influence DOA percentage, and which can be reduced relatively easily, were compartment stocking density (OR = 1.09 for each additional bird in a compartment), transport time (OR = 1.06 for each additional 15 min), and lairage time (OR = 1.03 for each additional 15 min). In particular, reduction of transport and lairage times might have a major influence due to their large variations. Reducing or removing these factors will reduce DOA percentage. Consequently, profitability and animal welfare will increase

Influences of feeding conventional and semisynthetic diets and transport of broilers on weight gain, digestive tract mass, and plasma hormone and metabolite concentrations

Two replicate experiments were done to investigate if special diets provided to broilers in their last phase of life could reduce the negative effects of feed withdrawal and transport without an increased content of the digestive tract. In each experiment, 240 broilers were used. The experiments consisted of 2 interventions: the feed intervention and the transport intervention. The feed intervention took 72 h, in which broilers had full access to a conventional grower diet, a conventional grower diet with an increased carbohydrate level, a conventional grower diet with an increased fat level, a semisynthetic diet, or a semisynthetic diet with an increased carbohydrate level. The diets differed remarkably in carbohydrate content; carbohydrate content was approximately 67% in the semisynthetic diets and 42%, on average, in the conventional diets. Moreover, all of the carbohydrates in semisynthetic diets were highly soluble and digestible. The diets were compared with a feed withdrawal period of 24 h before transport. The transport intervention took 3 h; broilers were caught, crated, loaded, transported for 1.5 h, and had to wait in the crates for I h thereafter; or remained in the pens. After the transport intervention, blood samples were taken to determine plasma corticosterone, triiodothyronine, glucose, lactate, uric acid, nonesterified fatty acid, and triglyceride concentrations. Also, changes in live weight (LW) and digestive tract mass were assessed. The LW losses of broilers fed with semisynthetic diets after transport were 0.24% per hour less than of feed-withdrawn broilers. Moreover, intake of semisynthetic diets was approximately 200 g, whereas the intake of conventional diets was approximately 300 g. Therefore, the digestive tract mass as a percentage of LW was lower for semisynthetic-fed broilers in comparison with conventional-fed broilers, which can lead to a lesser degree of contamination during evisceration. No increase of corticosterone was found due to transport in semisynthetic-fed broilers. Semisynthetic feed with high carbohydrate concentration could be a good alternative for the feed withdrawal period held before transportation to the processing plant

Pathological features in dead on arrival broilers with special reference to heart disorders

A gross postmortem investigation was done on 302 broilers that died between catching and slaughter to establish predisposing factors for dying in this period. Special attention was paid to heart disorders, which were established by determining the ratio of the right ventricle mass to the total ventricle mass (RV:TV) and to postmortem changes in hearts and lungs of broilers that were dead on arrival (DOA). Macroscopic pathologic lesions were found in 89.4% of DOA broilers. Signs of infectious diseases appeared to be most frequent (64.9%), followed by heart and circulation disorders (42.4%), and trauma (29.5%). The RV:TV was significantly higher for DOA broilers in comparison with slaughtered broilers. The prevalence of hearts with an abnormal RV:TV in DOA broilers was 34.4 vs. 4.1% in slaughtered broilers. The DOA broilers with an abnormal heart ratio more frequently showed ascites and hydropericardium. Postmortem changes in lungs depend on the position of the carcass the first several hours after death. Broilers, which remain in dorsal recumbency for several hours after death, develop engorged lungs. A good health status as well as more attention for the catching and crating process is crucial in decreasing the percentage of DOA broilers. Prevention of an increased heart ratio and of ascites will improve the livability in the broiler house and also decrease the DOA rate enormousl

Comparison of bruises ad mortality, stress parameters, and meat quality in manually and mechanically caught broilers.

A field trial was conducted to compare manual catching of broilers with a mechanical catching method. Both methods were compared with respect to the incidence of bruises and dead on arrival, stress parameters, and meat quality. Also the dynamics of corticosterone, glucose, and lactate were investigated on the day broilers were killed. The broilers originated from 8 commercial broiler farms; visits were made on the day of catching during spring and autumn of 2001. Broilers of one house were caught manually, and those of the second house were caught mechanically. Plasma samples were taken before catching started, 30 min after the start of catching, 30 min before the end of catching, and at exsanguination of broilers from the first- and last-loaded transport vehicles. Postmortem measurements of pH, temperature, and water-holding capacity were made. Mechanical catching was associated with higher DOA percentages than manual catching in spring, although the difference was not significant in autumn. Catching method did not influence the percentage of bruises or meat quality. Moreover, corticosterone levels indicated that both methods induced the same amount of stress. The dynamics of corticosterone, glucose, and lactate levels showed a similar pattern. Plasma levels increased at the start of catching, and they further increased during transport, shackling, and stunning. However during catching itself, no large changes were observed. Our findings indicated that attempts to reduce stress in broilers during the last day of life could better be focused on factors other than catchin

Feed withdrawal of broilers before transport changes plasma hormone and metabolite concentrations

Two experiments were completed to observe the combined effects of feed withdrawal and the catching and transport process on stress and energy metabolism. During one experiment 192 male broilers (46 d of age) were used, and in the other we used 240 male broilers (49 d of age). The experiments consisted of 2 interventions: feed intervention and transport intervention. The feed intervention took 10 h, in which broilers had full access to feed or feed was withdrawn and, thereafter, had a transport intervention that took 3 h, in which broilers were caught, crated, loaded, transported, and then had to wait in the crates for 1 h or remained in the pens. After the transport intervention, blood samples were taken to determine plasma corticosterone, triiodothyronine, thyroxine, glucose, lactate, uric acid, nonesterified fatty acid, and triglyceride concentrations. Changes in BW were also assessed. Broilers from which feed was withdrawn before the transport intervention showed higher thyroxine concentration and lower triiodothyronine, triglyceride, glucose, and lactate concentrations compared with broilers that had access to feed before the transport intervention. These findings indicate a negative energy balance and stress. Broilers that were transported after feed withdrawal had BW losses of approximately 0.42% per hour, which is approximately 0.30% per hour more than those that had full access to feed. To continue feeding broilers until catching resulted in higher BW at the slaughterhouse and less stress, as shown by a negative energy balance and might improve meat quality