Impact of pre-slaughter factors on welfare of broilers

Abstract

Pre-slaughter factors adversely affecting bird welfare were studied at the slaughterhouse. The incidence of dead on arrival (DoA), bruises and dehydration was investigated in 64 different mixed-sex batches of broilers coming from 64 different farms rearing fast-growing genotypes (Ross or Cobb). The effects of catching team, method of catching, time of day for catching and transport, density per cage, transport duration, transport distance, lairage duration and water withdrawal were considered. The average DoA was 0.29%, ranging from 0.02% to 1.89% per batch. DoA rate has a higher probability of increase with the increase in transport distance (t=2.142; P =0.037; estimate=0.009) and with catching the birds after midnight (t=-2.931; P =0.005; estimate=0.022). Longer transport durations for birds caught after midnight as well as longer lairage durations for birds caught after midnight are associated with the increase of DoA rate. Bruises were observed in 3.37% of birds, ranging from 0.43% to 8.29% per batch. Bruises occurred mostly on wings (3.06%), followed by legs (0.19%) and breast (0.12%). A higher percentage of bruises occurred in batches with more birds per transport crate (t=2.185; P =0.029; estimate=0.001). Dehydrated carcasses were observed in 22 out of 64 batches, accounting for 2.68% of condemnations. Signs of dehydration on carcasses were more frequently observed in batches subjected to longer withdrawal durations. Short transport distances, catching the birds before midnight and doing the transport by night are crucial in decreasing the DoA rate. Catching and crating processes seem to be responsible for the increase of percentage of bruises. Pre-slaughter operations should be adequate planned namely, transport and lairage durations, catching period and crating procedure in view to reduce negative effects on animal welfare.

Traumatic Injuries Detected during Post-Mortem Slaughterhouse Inspection as Welfare Indicators in Poultry and Rabbits

“…Jacobs et al [ 11 ] found that catching at the farm had a significant effect on the incidence of wing fractures in broilers (the difference in prevalence at the farm and after catching was 0.12% and 1.88%, respectively, and rose to a mean of 1.95% post mortem, which could include machine damage). In addition, when evaluating the factors that influenced the incidence of bruising in broilers at slaughterhouses, Saraiva et al [ 12 ] and Langkabel et al [ 8 ] observed the most bruising on wings. On the other hand, Gouveia et al [ 49 ] observed more bruising on the body (pectoral musculature) than the legs and/or wings, which was probably due to increased injuries caused by untrained personnel on the openings of transport containers.…”

“…Other risk factors include duration of catching and time of the day of the catching, where positive correlation was found between the prevalence of wing fractures and duration of catching and loading, and the risk of bruising also increased when birds were loaded at night [ 11 ]. Conversely, Saraiva et al [ 12 ] observed a higher percentage of bruising when birds were caught before midnight and Nijdam et al [ 10 ] observed more bruising in broilers transported during the day than at night. The process of hanging and stunning increases the prevalence of traumatic wing injuries due to wing flapping and consequent wing injuries [ 18 , 19 ].…”

“…However, pre-slaughter handling is a multi-step process and several factors influence the risk of injury to broilers during this handling [ 5 ]. Key risk factors that have been identified include the condition of the bird prior to transport and the method of animal handling [ 6 , 7 , 8 , 9 ], the duration of transport and the time of catching [ 10 , 11 , 12 ], and the stocking density within containers [ 12 ]. Most injuries resulting from pre-slaughter handling are found on the wings, and less frequently on the limbs and trunk [ 8 , 9 , 11 ].…”

The Effect of Ambient Temperature on The Death Rate, Reject Rate, Dressing Percentage, and Economic Loss in Broilers During Transport to Slaughterhouse

“…A recent study reported that the high per crate density during transport increases the bruises percentage (3.37%) in broilers. 4 On processing plants from receiving to post-slaughter, injuries may occur, which may raise the reject rates of birds or their meat. 21 All these bruises, traumas, wing and leg dislocations, sternum, and other bone fractures result welfare concerns to chickens, rising reject rates and ultimately economic loss.…”

“…1 Various on-farm and pre-slaughter risk factors involved in the death of the birds are reported as the flock size, sex, age, on-farm mortality and culling, feed withdrawal and previous pathological condition, catching day, catching time, catching method, stocking density and size, vehicle, transportation time, season, environmental condition, transportation and lairage duration. [2][3][4] Many conditions during transportation are critical risk factors, and a chicken's death is a response to these vital conditions. Thermal conditions during transportation have primary concern and drop the survival percentage of the transported poultry.…”