Breeding for better welfare: genetic goals for broiler chickens and their parents

Abstract

Genetics is key to the improvement of welfare in broiler chickens at both juvenile and adult (breeder) stages but progress is hampered currently by the seemingly conflicting demands of welfare, commercial production, food security and calls for increasing intensification to curb climate change. Animal welfare is therefore most likely to be improved on a commercial scale by future breeding programmes that incorporate multiple goals of different stakeholders as far as possible and give higher priority to animal welfare. These include: i) broilers with high welfare traits; ii) broiler breeders that do not need feed restriction; iii) birds that can be grown in an economically profitable way; iv) birds with low disease levels without the need for routine medication; v) chicken meat that is healthy and good for humans to eat; and (vi) broilers and breeders that thrive in systems that are environmentally sustainable. Progress towards achieving these goals is hampered currently by the assumptions that high juvenile growth rate is incompatible with good welfare and that feed restriction in adults is inevitable with fast-growing juveniles. We challenge these assumptions at both genetic and whole-animal level and argue that the conflict between good welfare and productivity can be reduced by making use of all available genetic variation from existing breeds and other sources and selecting birds in the range of environments they will encounter in commercial production.

Effects of the level and duration of feeding restriction on carcass components of broilers

“…Selection effects are displayed in carcass composition and structure, growth pattern, metabolism, digestion, endocrine and immune functions, central nervous system functions, and even in the behaviour of broilers (Khajavi et al, 2003;Dawkins and Layton, 2012). Cardiovascular disorders, skeletal disease and higher susceptibility to other metabolic diseases are commonly reported in commercial broilers.…”

“…Moreover, increased pressure on legs and hips leads to limb abnormalities, which reduces the ability to move (Caplen et al, 2012). Ultimately, mortality and welfare are also associated with broiler rapid growth (Leeson and Summers, 2001;Dawkins and Layton, 2012).…”

Sıklığa Maruz Bırakılmış Broylerlerde Rasyona Organik ve Inorganik Manganez İlavesinin Kemik Özellikleri, Aşılara Karşı İmmun Yanıt ve Oksidatif Stres Durumuna Etkileri

“…Each dietary treatment was comprised of 100 birds which were further sub-divided into four replicates, each replicate containing 25 birds. The organic Mn groups were fed diets supplemented with 6.25, 12.5 and 25 mg/ kg Mn-methionine, inorganic Mn groups were offered diets containing 12.5, 25 and 50 mg/kg Mn-oxide and organic + inorganic Mn groups were fed diets containing 3.125 mg/kg Mn-methionine + 6.25 mg/kg Mn-oxide, 6.25 mg/kg Mn-methionine + 12.5 mg/kg Mn-oxide and 12.5 mg/kg Mn-methionine + 25 mg/kg Mn-oxide. The nutrient composition of the basal diet (Table 1), including crude protein and calcium was determined according to the AOAC [32] .…”

“…Especially, the impacts of high stocking density in broilers on the foot health, lameness or gait disturbance, tibial dischondroplasia, gait scores, carcass bruising and scratching were reported in many researches. At finaly, the leg abnormalities result in culling, mortality and economic losses [6,10,11] .…”

“…The poultry meat production which occurred as 103 million tons in 2010 is predicted to reach 122.5 million tons in 2020 [2] . This growth springs from modern broiler genotypes obtained from intense selections applied for juvenile growth rate, breast-meat yield and feed efficiency [3][4][5] , and intensive production systems where high-tech is used [6] .…”