Havenstein G B, Ferket P R, Scheideler S E, Larson B T
Department of Poultry Science, North Carolina State University, Raleigh 27695-7608.
Poult Sci. 1994 Dec;73(12):1785-94. doi: 10.3382/ps.0731785.
The relative contributions of genetic selection and dietary regimen on the performance of broilers was assessed. Body weight, feed consumption, mortality (M), and the degree of tibial dyschondroplasia (TD) were measured in the 1957 Athens-Canadian Randombred Control (ACRBC) strain of broilers and in the 1991 Arbor Acres (AA) feather-sexable strain when fed "typical" 1957 and 1991 diets. Energy and protein levels, vitamin and mineral packs, and the coccidiostats used in the two dietary regimens were chosen to be representative of those in use by the industry for the two time periods. Eight treatment groups, i.e., two strains, two sexes, and two dietary regimens, were assigned into four blocks of eight litter floor pens for grow out. The 1957 diets were fed as mash, and the 1991 starter and grower diets were fed as crumbles and pellets, respectively. Feed consumption and BW were recorded at 21, 42, 56, 70, and 84 d of age, a period covering the normal marketing ages for the two broilers. Mortality and the cause of death was recorded daily. The incidence and severity of TD was assessed using a Lixiscope at 42 d of age. Average BW were 190, 508, 790, 1,087, and 1,400 g for the ACRBC on the 1957 diets vs 700, 2,132, 3,108, 3,812, and 4,498 g for the AA on the 1991 diets at 21, 42, 56, 70, and 84 d of age, respectively. The 1991 diets increased the BW of the AA by an average of 14% (20% at 42 d, but only 8% at 84 d) and of the ACRBC by 22%. The BW advantage for the 1991 diet over the 1957 diet for the AA was less for males than for females after 42 d of age, and the advantage decreased with age, probably due to the increasing incidence of leg problems. The M for AA was 9.1% vs 3.3% for the ACRBC at 42 d. Most of the ACRBC M occurred before 21 d, whereas M occurred throughout for the AA, with most after 21 d due to flip-overs and ascites. The feed conversion at 42 d for the ACRBC on the 1957 diet was 3.00 vs 2.04 for the AA on the 1991 diet. The AA on the 1991 diet had a 48.6% incidence of TD vs 25.6% on the 1957 diet. The ACRBC had approximately 1.2% TD on both diets. The TD was more severe with the 1991 diet.
评估了遗传选择和饮食方案对肉鸡生产性能的相对影响。在1957年雅典-加拿大随机繁殖对照（ACRBC）品系肉鸡和1991年阿伯丁安格斯（AA）羽色自别雌雄品系肉鸡中，当分别饲喂“典型的”1957年和1991年日粮时，测量了体重、采食量、死亡率（M）和胫骨软骨发育不良（TD）程度。两种日粮方案中的能量和蛋白质水平、维生素和矿物质预混料以及抗球虫药均选择为代表该行业在这两个时期所使用的产品。八个处理组，即两个品系、两个性别和两种日粮方案，被分配到四个由八个地面垫料栏组成的区组中进行育肥。1957年的日粮以粉料形式饲喂，1991年的开食料和生长料分别以破碎料和颗粒料形式饲喂。在21、42、56、70和84日龄记录采食量和体重，这一时期涵盖了两种肉鸡的正常上市日龄。每天记录死亡率和死亡原因。在42日龄时使用Lixiscope评估TD的发病率和严重程度。对于ACRBC，在1957年日粮下，21、42、56、70和84日龄时的平均体重分别为190、508、790、1087和1400克；而对于AA，在1991年日粮下，相应日龄的平均体重分别为700、2132、3108、3812和4498克。1991年的日粮使AA的体重平均增加了14%（42日龄时增加20%，但84日龄时仅增加8%），使ACRBC的体重增加了22%。42日龄后，1991年日粮相对于1957年日粮对AA的体重优势在雄性中比雌性小，且该优势随年龄增长而降低，这可能是由于腿部问题发生率增加所致。42日龄时，AA的死亡率为9.1%，而ACRBC为3.3%。ACRBC的大多数死亡发生在21日龄之前，而AA的死亡则贯穿整个时期，大多数发生在21日龄之后，原因是翻身和腹水。1957年日粮下ACRBC在42日龄时的饲料转化率为3.00，而1991年日粮下AA的饲料转化率为2.04。1991年日粮下AA的TD发病率为48.6%，而1957年日粮下为25.6%。两种日粮下ACRBC的TD发生率约为1.2%。1991年日粮下的TD更严重。
