Effect of transportation distances, seasons and crate microclimate on broiler chicken production losses

Mortality risk on farm and during transport: a comparison of 2 broiler hybrids with different growth rates

Mortality in broilers is often associated with poor health and welfare and has a complex and multifactorial etiology. Recent studies under experimental conditions indicated that genetic selection for fast growth is an important risk factor for mortality in broiler chickens. However, the knowledge on broiler mortality in general, and in slower growing broilers in particular, under commercial conditions is still limited. This retrospective cohort study aimed to describe mortality risk on farm and during transport in 2 broiler hybrids with different growth rates, Ross 308, and Hubbard JA787, and to estimate the association between hybrid and mortality at different stages of the production cycle. The study sample consisted of 64,651,804 broilers from 4,228 flocks and 139 farms slaughtered from January 1st, 2015, to June 22nd, 2021. Analysis of on-farm mortality was restricted to broiler flocks slaughtered in the period July 2017 to July 2018 due to changes known to affect FWM. The effect of hybrid on mortality during 3 different production stages (first week mortality (FWM), mortality after the first week (MAFW), and mortality during transport (DOA)), was assessed using mixed effect negative binomial regression models. Descriptively, there were notable differences in mortality at all stages of the production cycle, with higher mean mortalities in Ross 308 (1.40% FWM, 3.05% MAFW, and 0.063% DOA) than in Hubbard JA787 (0.76% FWM, 1.49% MAFW, and 0.015% DOA). In the analysis, the largest estimated difference was found for dead on arrival under cold conditions, where mortality was almost 5 times higher in Ross 308 compared to Hubbard JA 787 (IRR: 4.70, 95% CI: 3.74-5.90). The estimated difference in FWM between hybrids was highest during autumn, with an estimated risk approximately 1.6 times higher in Ross than in Hubbard (IRR: 1.56, 95% CI: 1.30-1.86). For MAFW, the estimated risk was approximately 2 times higher in Ross than in Hubbard (IRR: 2.13 95% CI: 1.82-2.49). The findings in this study emphasize the need for more knowledge on causes of mortality in broilers including effects of genetic factors as basis for preventive measures.

Quantitative analysis of knowledge, attitude and practice of workers in chicken slaughter slabs toward food safety and hygiene in Ouagadougou, Burkina Faso

Introduction

In low- and middle-income countries, chicken serves as a cheap source of protein and an income source for many households. It is particularly important in the capital, Ouagadougou, Burkina Faso, where chicken is regularly consumed. However, hygiene standards are very low, posing a significant public health risk.

Methods

To better understand the food safety situation, we conducted a cross-sectional survey of the hygienic practices of 155 randomly selected chicken slaughter outlets and carcass shops with a semi-structured questionnaire.

Results and discussion

Of the outlets visited, 59% are not licensed, and 63% are not regularly inspected, operating in the dominant, largely unregulated informal sector. More than 80% of the chickens are sourced from village production systems, but around 6% of the birds die during transport. The monetary loss due to chicken death during transportation is around four million USD annually. Market hygiene is poor; 86% of the holding pens have no hard floor and are not washed regularly. Almost all (92%) chickens are slaughtered on bare earth floors; bleeding, plucking, and evisceration are done on a wooden table that is rarely washed. On average, the same scalding water is used for 33 birds, seven scalded at a time. Most respondents (49%) thought that plucking and evisceration were the major cause of contamination of carcasses with foodborne pathogens. Most operators only washed their hands and knives with tap water at the beginning of the slaughtering process. Some shops use refrigerators and freezers to store carcasses before selling. However, they store carcasses with other foods like fish, beef and vegetables, facilitating further cross-contamination. There were rats (26%), cats (39%) and dogs (30%) present at outlets, roaming for food, especially roadside outlets. Training schemes on hygienic food handling practices were favoured by outlets as an approach to improve matters; however, improvements in food safety will be limited without significant upgrades in infrastructure and facilities. Slaughter slabs need a standard house with stable energy, adequate airflow, clean water, toilets, detergents and freezers. Also, they need equipment like knives, tables and dishes made of high-quality, easy-to-clean materials.

Transmission of antimicrobial resistance (AMR) during animal transport

The transmission of antimicrobial resistance (AMR) between food-producing animals (poultry, cattle and pigs) during short journeys (< 8 h) and long journeys (> 8 h) directed to other farms or to the slaughterhouse lairage (directly or with intermediate stops at assembly centres or control posts, mainly transported by road) was assessed. Among the identified risk factors contributing to the probability of transmission of antimicrobial-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs), the ones considered more important are the resistance status (presence of ARB/ARGs) of the animals pre-transport, increased faecal shedding, hygiene of the areas and vehicles, exposure to other animals carrying and/or shedding ARB/ARGs (especially between animals of different AMR loads and/or ARB/ARG types), exposure to contaminated lairage areas and duration of transport. There are nevertheless no data whereby differences between journeys shorter or longer than 8 h can be assessed. Strategies that would reduce the probability of AMR transmission, for all animal categories include minimising the duration of transport, proper cleaning and disinfection, appropriate transport planning, organising the transport in relation to AMR criteria (transport logistics), improving animal health and welfare and/or biosecurity immediately prior to and during transport, ensuring the thermal comfort of the animals and animal segregation. Most of the aforementioned measures have similar validity if applied at lairage, assembly centres and control posts. Data gaps relating to the risk factors and the effectiveness of mitigation measures have been identified, with consequent research needs in both the short and longer term listed. Quantification of the impact of animal transportation compared to the contribution of other stages of the food-production chain, and the interplay of duration with all risk factors on the transmission of ARB/ARGs during transport and journey breaks, were identified as urgent research needs.

Effect of distance and daily periods on heat-stressed pigs and pre-slaughter losses in a semiarid region

Effective planning animal transport is essential to safeguard animal welfare and reduce production losses. Environmental conditions, specifically extreme temperatures in combination with ranges of relative humidity are highlighted as one of the main risk factors for production losses during transport (e.g., fatalities). The majority of research evaluating both welfare and production impacts of pig transport have been primarily undertaken in Europe and North America, which cover a relatively limited range of distinct climates (e.g., temperate, sub-arctic, etc.). As a result, research on pig transport in semi-arid conditions is lacking. In this study, we evaluated the effects of both distance (short, 30 km; and long, 170 km) and transport daily periods (morning, (05:00-11:00); afternoon (12:00-17:00); and night, (23:00-04:00)) on the preslaughter losses and heat stress of pigs in commercial transport in a semiarid region. Across 19 journeys of standard slaughter-weight pig loads (124.0 ± 2.8 kg), 684 focal animals (36 per journey) were evaluated. For each journey, the load's thermal profile (THI_adj and enthalpy) and physiological responses of individual pigs were recorded. On arrival at designated slaughterhouses, the percentage pig of non-ambulatory non-injured (NANI), non-ambulatory injured (NAI), death on arrival (DOA), and total losses were recorded. Short journeys in the afternoon were shown to be more detrimental to the thermal comfort of pigs, with higher rectal temperatures recorded. The highest percentage of total losses and DOA occurred in afternoon journeys, irrespective of distance, followed by the morning, with the lowest losses observed in pigs transported at night. Additionally, total losses and DOA were further exacerbated by journey distance, with higher rates observed in short journeys. Higher percentage averages of NANI and NAI were observed in shorter journeys, but daily periods effects were only observed for NANI. These results further demonstrate the welfare and production loss risks associated with journey distance and time of day (representing varying environmental conditions) during road transport of pigs, whilst providing novel data in semiarid conditions. Careful and effective planning for pig transportation is essential to minimize heat stress and production losses. Consideration of the thermal environment on the day of travel, as well as providing flexibility to adjust travel times (e.g., early morning or evening), should help to mitigate risks of heat stress and production losses during pig transport.

The 'sustainability gap' of US broiler chicken production: trade-offs between welfare, land use and consumption

In 2018, over nine billion chickens were slaughtered in the United States. As the demand for chickens increases, so too have concerns regarding the welfare of the chickens in these systems and the damage such practices cause to the surrounding ecosystems. To address welfare concerns, there is large-scale interest in raising chickens on pasture and switching to slower-growing, higher-welfare breeds as soon as 2024. We created a box model of US chicken demographics to characterize aggregate broiler chicken welfare and land-use consequences at the country scale for US shifts to slower-growing chickens, housing with outdoor access, and pasture management. The US produces roughly 20 million metric tons of chicken meat annually. Maintaining this level of consumption entirely with a slower-growing breed would require a 44.6%-86.8% larger population of chickens and a 19.2%-27.2% higher annual slaughter rate, relative to the current demographics of primarily 'Ross 308' chickens that are slaughtered at a rate of 9.25 billion per year. Generating this quantity of slower-growing breeds in conventional concentrated animal feeding operations (CAFO) would require 90 582-98 687 km2, an increase of 19.9-30.6% over the 75 577 km2 of land used for current production of Ross 308. Housing slower-growing breeds on pasture, the more individually welfare-friendly option, would require 108 642-121 019 km2, a 43.8-60.1% increase over current land use. Allowing slower-growing breeds occasional outdoor access is an intermediate approach that would require 90 691-98 811 km2, an increase of 20-30.7% of the current land use, a very minor increase of land relative to managing slower-growing breeds in CAFOs. In sum, without a drastic reduction in consumption, switching to alternative breeds will lead to a substantial increase in the number of individuals killed each year, an untenable increase in land use, and a possible decrease in aggregate chicken welfare at the country-level scale. Pasture-based management requires substantial additional land use. These results demonstrate constraints and trade-offs in animal welfare, environmental conservation and food animal consumption, while highlighting opportunities for policies to mitigate impacts in an integrated manner using a One Health approach.

Machine Learning Model for Assuring Bird Welfare during Transportation

Bird welfare and comfort is highly impacted by extreme environments, including hot/cold temperatures, relative humidity, and heat production within the coops during loading at the farm, transportation, and holding at the processing plants. Due to the complexity of the multiphysics phenomena involving fluid flow, heat transfer, and multispecies mixtures (humidity) within the coops, machine learning models may be helpful to evaluate broiler welfare under various environments. Machine learning techniques (Artificial Neural Networks and Bayesian Optimization) were applied to estimate the desired parameters required to ensure broiler welfare inside the coops. Artificial Neural Networks (ANNs) were trained with the results of Computational Fluid Dynamics (CFD) simulations for various ranges of inputs related to the microenvironment. Input variables included air velocity, broiler heat production, ambient temperature, and relative humidity. The Output variable was the Enthalpy Comfort Index (ECI), which is a measure of the bird welfare. The trained networks were then analyzed using Bayesian Optimization (BO) for the inverse mapping of ANNs and to predict the range of acceptable input parameters for a desired output, i.e., ECI in the comfort level. Results indicate that reducing the broilers heat production inside the coop along with increasing fan velocity enhances the broiler welfare and the thermal microenvironment. The BO developed in this study provide the microenvironmental parameters to estimate the bird welfare that is comfortable.

Effects of Season, Plumage Colour, and Transport Distance on Body Weight Loss, Dead-on-Arrival, and Reject Rate in Commercial End-of-Lay Hens

Simple Summary

The transport conditions of end-of-lay hens to slaughterhouses are essential for their welfare. In this study, the effect of season, plumage colour, and transport distance on body weight loss, dead-on-arrival rates, and reject rates was examined. Transport-related data of 31.6 million end-of-lay hens over a two-year period from one slaughter plant in Turkey were analysed. Hens transported in the winter and spring seasons had a greater body weight loss and reject rates. Brown-feathered hens had a higher death rate, while white-feathered hens had a higher body weight loss and reject rate. Hens transported longer distances for slaughter had increased body weight loss, death rates, and reject rates. These results indicate that more care should be taken when transporting end-of-lay hens in cold weather and over longer transport distances. We suggest the transport should be reduced to a certain distance, and improved conditions ought to be provided to mitigate losses.

Abstract

Transport conditions of end-of-lay hens are important for their welfare. This study investigated the effects of season, plumage colour, and transportation distance on the welfare of end-of-lay hens. Retrospective data from 31,667,274 end-of-lay hens transported to a poultry slaughterhouse in Turkey were analysed. The mean body weight loss, dead-on-arrival (DOA) rate, and reject rate were 3.723%, 1.397%, and 0.616%, respectively. The effects of season, plumage colour, and transport distance on the evaluated parameters were all statistically significant (p < 0.001). The highest body weight loss was found in winter, while the lowest body weight loss was found in autumn. The average DOA rate was highest in spring and lowest in autumn. The highest average reject rate was found in spring (0.630%). Body weight loss, DOA rates, and reject rates were also significantly different among white and brown hens (p < 0.001; p < 0.001; p = 0.016, respectively). The highest body weight loss and reject rates were found in white plumage hens, while the highest DOA rate was found in brown plumage hens. The body weight loss and DOA rate were positively correlated with transportation distance (p < 0.001). The results of this study indicate that more preventive measures should be taken during the transport of end-of-lay hens, especially in cold seasons such as winter, and over longer transport distances, in regard to the welfare of these animals. Additionally, the transport of these animals should be lessened to a certain distance.

The specific enthalpy of air as an indicator of heat stress in livestock animals

Along with recognition of environmental effects on the performance and welfare of livestock animals, studies have been proposing new methodologies and parameters to diagnose the heat stress of animals through the physical properties of air. This article aims to present the state-of-the-art on the use of the specific enthalpy of air as an indicator of heat stress in livestock animals. As a starting point, conceptual considerations were made about the connection between homoeothermic animals and the environment. Variables for heat stress evaluation based on psychrometric air properties are then described, including dry bulb temperature and relative humidity, which are often used microclimate variables, and the specific enthalpy of dry air, which acts as a thermal comfort index. Final considerations highlight the recent history of the use of specific enthalpy of air equations as indicators of heat stress in livestock animals, with the intention of better understanding the relationship between animals and the environment. As a conclusion, the specific enthalpy of air is recommended as an indicator in the assessment of livestock housing conditions as, unlike other indices, it is based on thermodynamic air properties and not on linear regressions.