Veterinary Epidemiology, Economics and Public Health Group, Royal Veterinary College, Hawkshead Lane, Hatfield, Hertfordshire, AL9 7TA, UK.
Research Support Office, Royal Veterinary College, Royal College Street, NW1 0TU, UK.
Prev Vet Med. 2020 Aug;181:105036. doi: 10.1016/j.prevetmed.2020.105036. Epub 2020 May 16.
Slaughterhouse condemnation of broiler chickens results from identification of polymorphic pathological conditions during meat inspection from arrival and on the slaughter line. While conditions that result in condemnation are multifactorial, identification of factors that are common for a number of categories could be valuable for developing strategies to reduce total condemnation. This study aimed to identify those condemnation categories that were most common in batches of broiler chickens and to determine and compare associated risk factors. In the first step, retrospective meat inspection records for 55,918 broiler batches from one large broiler integrator for 2015-2017 were used for association rules analysis. Results identified a network of nine associated condemnation categories: whole carcass condemnation for ascites, abnormal colour, perihepatitis, cellulitis, hard breast, tumours and dead on arrival, and liver only and heart only most often associated with hepatitis and pericarditis, respectively. Secondly, a longitudinal study collected data on 109 explanatory variables from broiler parental flocks to slaughterhouse characteristics between January 2015 and December 2017. Condemnation outcome data were obtained from meat inspection records for 539 broiler batches participating in the study. Parental flock-, rearing farm-, shed- and transport-level risk factors were assessed for each outcome using mixed-effects multivariable Poisson regression including shed and farm as random effects. A Poisson regression tree method was used as the first step to identify variables most relevant for analysis and comparison across the outcomes. No single production factor was associated with all nine of the condemnation outcomes investigated in this study, although some were shared across multiple outcomes: age of parental flock at time of lay, flock-level Campylobacter spp. frequency, broiler chick weight at seven days of age, weight at slaughter, type of broiler removal (i.e. thinning, final depopulation), catcher team, number of birds per transport crate, slaughterhouse shift number, and type of slaughterhouse line. Broiler chickens removed during final depopulation were at greatest risk of condemnation. Condemnation rates for cellulitis and tumours were found to be higher in broilers inspected by night shift at the slaughterhouse. Discovery of an apparent protective effect of a higher number of broilers per transport crate was unexpected. These findings provide information for the broiler industry on production chain factors that might be amenable to targeted intervention to improve future efforts for control of condemnation.
屠宰场对肉鸡的谴责源于在到达和屠宰线上进行肉品检验时发现多态性病理状况。虽然导致谴责的情况是多因素的，但确定对许多类别都普遍存在的因素对于制定减少总谴责的策略可能是有价值的。本研究旨在确定肉鸡批次中最常见的谴责类别，并确定和比较相关的危险因素。在第一步中，使用来自一家大型肉鸡综合企业 2015-2017 年的 55918 批肉鸡的回顾性肉品检验记录进行关联规则分析。结果确定了九个相关谴责类别的网络：腹水、颜色异常、肝炎、浆膜炎、硬胸、肿瘤和到达时死亡的全胴体谴责，以及肝脏和心脏的单独谴责，分别与肝炎和心包炎最相关。其次，一项纵向研究收集了 2015 年 1 月至 2017 年 12 月期间肉鸡父母群到屠宰场特征的 109 个解释变量的数据。从参与研究的 539 批肉鸡的肉品检验记录中获得谴责结果数据。使用混合效应多变量泊松回归评估每个结果的父母群、饲养场、畜舍和运输水平危险因素，包括畜舍和农场作为随机效应。泊松回归树方法被用作第一步，以确定对分析和比较各结果最相关的变量。没有单个生产因素与本研究调查的九个谴责结果都有关联，尽管一些结果在多个结果中是共享的：父母群在产卵时的年龄、种群水平弯曲杆菌属频率、肉鸡雏鸡 7 日龄体重、屠宰体重、肉鸡移除类型（即变薄、最终淘汰）、捕手队、每运输箱的鸟类数量、屠宰场班次数和屠宰线类型。在屠宰场最终淘汰期间被淘汰的肉鸡面临最大的谴责风险。发现屠宰场夜班检查时，浆膜炎和肿瘤的谴责率更高。发现每运输箱的肉鸡数量较高似乎有保护作用，这一发现出乎意料。这些发现为肉鸡行业提供了有关生产链因素的信息，这些因素可能适合针对性干预，以改善未来控制谴责的努力。
