Environment and management factors affecting Pekin duck production and welfare on commercial farms in the UK

Effect of different bedding depths of rice hulls on growth performance and carcass traits of White Pekin ducks

Duck meat is recognized as a healthier poultry product that contains higher amounts of unsaturated and essential fatty acids, iron, and excellent amounts of protein. It has been found to possess the ability to reduce low-density lipoprotein cholesterol and subsequently, blood pressure in the human body; and improve the immunity system. The current study investigated the appropriate bedding depths of rice hulls as a preferred bedding material by evaluating the growth performance and carcass traits of White Pekin ducks raised for 42 days. A total of 288 one-day-old White Pekin ducklings were randomly allotted to floor cages with one of four bedding depths at 4 cm, 8 cm, 12 cm, and 16 cm. Ducklings were fed standard duck starter (days 1-21) and finisher (days 22-42) diets. The birds were stocked at a rate of 6 birds/m2 with 6 replicates per treatment. Growth performance evaluation for the body weight, average daily gain, and average daily feed intake were measured to calculate the weekly feed conversion ratio. Breast, leg, and carcass yield were assessed as carcass traits. The muscle color and proximate composition were also analyzed for meat quality. Footpad dermatitis was also evaluated on day 42. Ducks reared on 16 cm bedding depth over the 42 days recorded higher (p < 0.05) body weight, average daily, average daily feed intake, and improved feed conversion ratios compared to other groups. The crude fat in breast meat also lowered (p < 0.05) in ducks reared at 16 cm (1.02%) when compared to ducks raised at 4 cm bedding depth (2.11%). Our results showed improved redness (p < 0.05) when the depth of bedding materials was elevated. Except for the breast meat fat, the dissimilar bedding depths did not affect (p < 0.05) the breast and leg meat composition, footpad dermatitis, and mortality for the current study. In conclusion, this study indicated that the bedding depths would directly or indirectly affect the growth performance and meat color of White Pekin ducks; and the bedding depth of rice hulls at 16 cm improved the growth performance of White Pekin ducks for 42 days.

Preening cups in duck housing are associated with an increase in central dopamine activity that suggests a negative affective state

Preening cups are a form of environmental enrichment that provides Pekin ducks a semi-open water source to express their natural behaviors. We recently observed that preening cups may increase feather pecking behaviors in ducks. Thus, we set out to determine if this form of enrichment can impact the affective state of Pekin ducks. To accomplish this goal, we evaluated the effect of preening cups on serotonin (5-HT) and dopamine (DA) turnover via mass spectrometry and their respective synthetic enzyme gene expression via qRT-PCR. Our study investigated the link between aggressive pecking with levels and activity of brain 5-HT and DA. Brain 5-HT and DA levels and activity have been established for decades to be associated with affective states. Grow-out Pekin ducks (n = 260) were housed at Purdue and raised per industry standards. On day 18, brains were collected from ducks in pens before preening cups were placed (PRE, n = 6) and, again on day 43, in pens with (PC, n = 6) and without (CON, n = 6) preening cups. Brains were dissected into right and left halves, then further microdissected into 4 brain areas: caudal mesencephalon (CM), rostral mesencephalon (RM), diencephalon (DI), and forebrain (FB). The right hemisphere was used for mass spectrometry to determine the neurotransmitter concentration (ng/mg of tissue) and those concentrations were applied to neurotransmitter turnover equations. There were no differences across treatments for 5-HT turnover in any brain area. There were differences in DA turnover across age (P = 0.0067) in the CM and across treatments (P = 0.003) in the RM. The left hemisphere of the brain was used to perform qRT-PCR on the genes of 5-HT and DA production enzymes. Within the CM, day 43 duck brains had increased (P = 0.022) tryptophan hydroxylase and tyrosine hydroxylase relative mRNA levels. All other brain areas showed no differences. Our data suggest that ducks housed with preening cups and that showed increased feather pecking are associated with increased brain DA activity. The increased DA in the brain may lead to a predisposition for increased aggression in the form of feather pecking.

Effects of ambient temperature on growth performance, slaughter traits, meat quality and serum antioxidant function in Pekin duck

The present study investigated the effects of temperature on growth performance, slaughtering traits, meat quality and antioxidant function of Pekin ducks from 21-42 d of age. Single factor analysis of variance was used in this experiment, 144 21 d-old Pekin ducks were randomly allotted to 4 environmentally controlled chambers: T20 (20°C), T23 (23°C), T26 (26°C) and T29 (29°C), with 3 replicates in each group (12 ducks in each replicate), the relative humidity of all groups is 74%. During the 21-day trial period, feed and water were freely available. At 42 d, the BW (body weight) and ADG (average daily gain) of T26 were significantly lower than T20 (p < 0.05), and the T29 was significantly lower than T20 and T23 (p < 0.05). The ADFI (average daily feed intake) of T26 and T29 were significantly lower than T20 and T23 (p < 0.05). Compared to the T29, the T20 showed a significant increase oblique body length and chest width, and both the keel length and thigh muscle weight significantly increased in both the T20 and T23, while the pectoral muscle weight increased significantly in other groups (p < 0.05). The cooking loss of the T29 was the lowest (p < 0.05). The T-AOC (total antioxidant capacity) of T29 was significantly higher than the other groups (p < 0.05), the SOD (superoxide dismutase) in the T29 was significantly higher than the T23 and T26 (p < 0.05). In conditions of 74% relative humidity, the BW and ADFI of Pekin ducks significantly decrease when the environmental temperature exceeds 26°C, and the development of body size and muscle weight follows this pattern. The growth development and serum redox state of Pekin ducks are more ideal and stable at temperatures of 20°C and 23°C.

Welfare of ducks, geese and quail on farm

This Scientific Opinion concerns the welfare of Domestic ducks (Anas platyrhynchos domesticus), Muscovy ducks (Cairina moschata domesticus) and their hybrids (Mule ducks), Domestic geese (Anser anser f. domesticus) and Japanese quail (Coturnix japonica) in relation to the rearing of breeders, birds for meat, Muscovy and Mule ducks and Domestic geese for foie gras and layer Japanese quail for egg production. The most common husbandry systems (HSs) in the European Union are described for each animal species and category. The following welfare consequences are described and assessed for each species: restriction of movement, injuries (bone lesions including fractures and dislocations, soft tissue lesions and integument damage and locomotory disorders including lameness), group stress, inability to perform comfort behaviour, inability to perform exploratory or foraging behaviour and inability to express maternal behaviour (related to prelaying and nesting behaviours). Animal-based measures relevant for the assessment of these welfare consequences were identified and described. The relevant hazards leading to the welfare consequences in the different HSs were identified. Specific factors such as space allowance (including minimum enclosure area and height) per bird, group size, floor quality, characteristics of nesting facilities and enrichment provided (including access to water to fulfil biological needs) were assessed in relation to the welfare consequences and, recommendations on how to prevent the welfare consequences were provided in a quantitative or qualitative way.

Dietary Zinc Glycine Supplementation Improves Tibia Quality of Meat Ducks by Modulating the Intestinal Barrier and Bone Resorption

Leg problems characterized by gait abnormity and bone structure destruction are associated with a high risk of fractures and continuous pain in poultry. Zinc (Zn) acts a pivotal part in normal bone homeostasis and has proven to be highly effective in alleviating leg problems. Therefore, the effects of graded concentration of Zn on bone quality were evaluated in this study. A total of 512 1-d-old male ducks were fed 4 basal diets added 30 mg/kg Zn, 60 mg/kg Zn, 90 mg/kg Zn, and 120 mg/kg Zn as Zn glycine for 35 d. Tibia Zn content, ash percentage, and breaking strength linearly increased with dietary elevated Zn level (P < 0.05). Broken-line analysis revealed that the recommended level of Zn from Zn glycine was 55.13 mg/kg and 64.48 mg/kg based on tibia ash and strength, respectively. To further confirm the role of dietary Zn glycine addition on bone characteristics, data from birds fed either 60 mg/kg Zn as Zn sulfate (ZnSO₄), 30 mg/kg Zn, or 60 mg/kg Zn in the form of Zn glycine indicated that birds given 60 mg/kg Zn from Zn glycine diet exhibited higher tibia ash, strength, and trabecular volume compared to those fed the 30 mg/kg Zn diet (P < 0.05). Dietary 60 mg/kg Zn as Zn glycine addition decreased intestinal permeability, upregulated the mRNA expression of tight junction protein, and increased the abundance of Lactobacillus and Bifidobacterium, which was companied by declined the level of inflammatory cytokines in both the ileum and bone marrow. Regarding bone turnover, the diet with 60 mg/kg Zn from Zn glycine induced osteoprotegerin expression and thus decreased osteoclast number and serum bone resorption biomarker levels including serum tartrate-resistant acid phosphatase activity and C-terminal cross-linked telopeptide of type I collagen level when compared to 30 mg/kg Zn diet (P < 0.05). Except for the upregulation in runt-related transcription factor 2 transcription, the experimental treatments did not apparently change the bone formation biomarker contents in serum. Additionally, Zn glycine displayed a more efficient absorption rate, evidenced by higher serum Zn level, and thus had potentially greater a protective role in the intestine barrier and tibia mass as compared to ZnSO₄. Collectively, the dietary supplementation of 60 mg/kg in the form of Zn glycine could suppress bone resorption mediated by osteoclast and consequently improve tibial quality of meat ducks, in which enhanced intestinal integrity and optimized gut microbiota might be involved.

Effects of Swimming Pool Conditions and Floor Types on White Roman Geese's Physical Condition Scores and Behaviors in an Indoor Rearing System

Biosecurity problems, including the continual risk of avian influenza spread by wild birds, have severely affected traditional free-range waterfowl production systems. Regulations and techniques for indoor goose production require more considerations for animal welfare. This study investigated the effects of swimming pool conditions and different floor types on the physical condition scores and behaviors of indoor-reared White Roman geese. A total of 48 male and 48 female White Roman geese reared from the age of 15 to 84 days were randomly allocated to pens with or without a swimming pool and with either mud or perforated plastic floors. Providing a swimming pool improved geese's eye and feather cleanliness and breast blister scores at the age of 84 days. Compared with geese reared on a mud floor, those reared on a perforated plastic floor had better feather cleanliness and higher breast blister scores at the age of 56 and 84 days. Providing a swimming pool to indoor-reared geese may reduce the proportion of abnormal behaviors, such as injurious feather pecking, by increasing water-related behaviors. This study suggests a more appropriate environment design for better balancing commercial goose production with animal welfare in an indoor rearing system.

Online estimating weight of white Pekin duck carcass by computer vision

The increasing consumption of ducks and chickens in China demands characterizing carcasses of domestic birds efficiently. Most existing methods, however, were developed for characterizing carcasses of pigs or cattle. Here, we developed a noncontact and automated weighing method for duck carcasses hanging on a production line. A 2D camera with its facilitating parts recorded the moving duck carcasses on the production line. To estimate the weight of carcasses, the images in the acquired dataset were modeled by a convolution neuron network (CNN). This model was trained and evaluated using 10-fold cross-validation. The model estimated the weight of duck carcasses precisely with a mean abstract deviation (MAD) of 58.8 grams and a mean relative error (MRE) of 2.15% in the testing dataset. Compared with 2 widely used methods, pixel area linear regression and the artificial neural network (ANN) model, our model decreases the estimation error MAD by 64.7 grams (52.4%) and 48.2 grams (45.0%). We release the dataset and code at https://github.com/RuoyuChen10/Image_weighing.

Behavior and welfare impacts of water provision via misting in commercial Pekin ducks

Ducks will access water to maintain feather condition and exhibit natural water-related behaviors such as wet preening. Providing water to ducks commercially is challenging as it may reduce litter and air quality leading to higher duck mortality or illness. This research aimed to measure the behavioral and welfare impacts of water provision via a misting system for commercial Pekin grower ducks in Victoria, Australia. Seven grower flocks were observed (four misted and three nonmisted in open-sided sheds) during May and November 2021. From 26 until 33 d of age, treatment ducks were provided 1 h of misting with shed curtains closed in both treatment and control sheds. At the start and end of the misting application period, external health and welfare measures were taken directly on the ducks via transect walks throughout each shed and catch-and-inspect observations on a sample of 150 ducks from each shed. Video recordings were also made of the misted and nonmisted ducks for 3 h representing time periods prior to, during, and after the 1-h misting across all sheds for all 8 d of the treatment period. Observations were made of all behavior that ducks exhibited at 10-min scan sample intervals across four cameras per shed, totaling 4,198 scans across the seven sheds. General linear mixed models showed the misting application predominantly had impacts on the patterns of behavioral change across the treatment time periods between the misted and nonmisted ducks rather than increasing or decreasing the overall expression of specific behaviors (interaction terms all P ≤ 0.003). The misted ducks increased drinking, tail wagging, and walking, and reduced preening, rooting litter, sitting, and stretching during misting relative to what they showed prior. The nonmisted ducks showed less sitting and more panting during misting relative to prior. Pearson's Chi-square tests showed some differences between the treatment groups in feather cleanliness on the back and wings (both P < 0.0001), likely resulting from pre-existing differences between sheds in blood from pin feathers. Most welfare indicators showed no positive or negative effect of the misting treatment. These results indicate overhead misting does affect duck behavior to some degree without compromising their welfare, but further research with larger water droplet sizes resulting in greater accumulation of surface water or extended durations of misting may lead to greater effects.

Effects of feed trough positioning height on growth performance, feed loss, feeding environment, and behavior of geese

In the traditional feeding pattern of geese, the feed trough will be placed on the ground for a long time and hurts the living environment. This research aimed to investigate the effect of 4 different feed trough positioning heights on growth performance, blood parameters, feed loss, water consumption, feeding environment, and behavior of geese and determine the optimal trough positioning height for 28 to 70-d geese. A total of one hundred ninty-two 28-d male Yuzhou white geese were allocated randomly to 4 groups with 6 replicate pens per group according to the trough positioning height (on the ground [D], one-third [L], two-thirds [M], and the same height of geese's beak above the ground [H], respectively). The results show that the growth performance and blood biochemical parameters have no significant difference among groups (P > 0.05). The average daily feed loss and water consumption presented the lowest value in group H (P < 0.01). The hygienic condition index of the feed and feed trough increased as trough positioning height. Feed from group H had a higher cleanliness score than other groups (P < 0.001). The count of microbes (total bacteria, Staphylococcus aureus, and Escherichia coli) on the surface of the feed trough from group H was lower than other groups (P < 0.001). Geese from group H had shorter daily feeding and drinking time than other groups (P < 0.05). Overall, these data indicate the same trough positioning height with geese's beaks could lower feed loss, and water consumption and improve hygienic conditions without damage to growth performance and will be the optimal choice for geese.

The effects of stocking density on slaughter performance and some meat quality parameters of Pekin ducks

The effects of stocking density on slaughter performance and meat quality were primarily investigated in this research. A total of 240 Pekin ducks were used, and they were reared until slaughter age (42 d) in three different stocking density groups (three, five and seven ducklings m-2). To compare the slaughter performance of the ducklings' live weight, carcass weight, carcass yield, thigh and breast meat weight and yield, and edible giblet weight (heart, liver and gizzard) were investigated. The meat quality was compared between the treatment groups based on dry matter ratio, cooking loss, water-holding capacity, pH values, and colour parameters (L, a, b, c, h and ΔE values). Carcass weight, carcass yield, thigh and breast meat weight were found to decrease in parallel to the increasing stocking density, resulting in a reduction in thigh and breast meat weights and ratios (P<0.05). Increasing the stocking density decreased the heart weight and positively improved the liver and gizzard ratio (P<0.05). However, it did not affect the meat quality parameters investigated in this research (P<0.05). The breast meat of the ducks reared under higher stocking density had higher L, h and ΔE values, lower a value (P<0.05), and similar b and c values (P<0.05). Evaluating the overall research findings, it was concluded that increased stocking density when rearing ducks negatively affects the slaughter performance, affecting only breast meat colour and weight of thigh meat with skin in investigated meat quality parameters.

Dietary Resistant Starch From Potato Regulates Bone Mass by Modulating Gut Microbiota and Concomitant Short-Chain Fatty Acids Production in Meat Ducks

Gut microbiota interfered with using prebiotics may improve bone mass and alleviate the onset of bone problems. This study aimed to investigate the beneficial effect of resistant starch from raw potato starch (RPS) on bone health in meat ducks. Response to the dietary graded level of RPS supplementation, both tibia strength and ash were taken out linear and quadratic increase and positively correlated with increased propionate and butyrate levels in cecal content. Moreover, further outcomes of gut microbiota and micro-CT analysis showed the beneficial effect of RPS on bone mass might be associated with higher Firmicutes proportion and the production of short-chain fatty acids (SCFAs) in the cecum. Consistent with improving bone mass, SCFAs promoted phosphorus absorption, decreased the digestive tract pH, and enhanced intestinal integrity, which decreased the expression of pro-inflammatory genes in both gut and bone marrow, and consequently depressed osteoclastic bone resorption mediated by inflammatory cytokines. These findings highlight the importance of the "gut-bone" axis and provide new insight into the effect of prebiotics on bone health.

Setting research driven duck-welfare standards: a systematic review of Pekin duck welfare research

Globally, the production of Pekin ducks for meat and eggs is considerable, with an estimated >200 million ducks slaughtered yearly for their meat in the United States and the European Union alone. However, despite the size of the Pekin duck industries, there is a lack of research-based guidance regarding the welfare of the ducks. The purpose of this systematic review is to examine and summarize available scientific literature related to the welfare of Pekin ducks raised on commercial farms for meat and eggs. Specifically, we aimed to identify topics where sufficient literature exists to support best-practice duck welfare recommendations, as well as further research needs. The literature search targeted original research papers and review articles published in English. Six pre-establish inclusion/exclusion criteria were applied, yielding 63 publications. We summarized their content based their main topic of focus. For all original studies, we additionally recorded the country where the study was executed, scale of the project (commercial or experimental barns), general information about the housing system and management (waterers, flooring, ventilation, group size, and space allowance), and the types of outcome variables collected. We begin with an overview of key publication trends. We then synthesize and discuss welfare outcomes related to key housing/management decisions: bathing water, flooring and litter, stocking density and space availability, ventilation/air quality, lighting, outdoor access, and for egg laying birds the availability of nest boxes. Throughout, we outline specific research gaps, as well as overarching research needs.

Water for Domestic Ducks: The Benefits and Challenges in Commercial Production

Although we have been farming ducks for at least 4,000 years, with some accounts suggesting domestication having begun more than 38,000 years ago, there are still many unknowns for optimizing domestic duck welfare in a commercial setting. Ducks being waterfowl, are semi-aquatic and have unique behavioral needs when compared to other commonly farmed poultry species. Providing ducks with open water which allows for full body immersion so that they may perform their full repertoire of water-related behaviors is important for their health and welfare. However, in a commercial setting this remains challenging due to biosecurity, contamination, health, and management concerns. An important question is therefore how best to provide ducks with a commercially feasible and safe water source in which they can derive maximum welfare and health benefits with no adverse consequences to health or global water resources. This review considers the amount of water provision necessary to satisfy duck's water-related needs to enhance yet not compromise their welfare in a commercial setting based on current knowledge, as well as identifies the outstanding questions for future research to address.

Centennial Review: History and husbandry recommendations for raising Pekin ducks in research or commercial production

By some accounts, ducks were domesticated between 400 and 10,000 yr ago and have been a growing portion of the poultry industry for decades. Ducks specifically, and waterfowl in general, have unique health, housing, nutrition and welfare concerns compared to their galliform counterparts. Although there have been many research publications in regards to health, nutrition, behavior, and welfare of ducks there have been very few reviews to provide an overview of these numerous studies, and only one text has attempted to review all aspects of the duck industry, from breeders to meat ducks. This review covers incubation, hatching, housing, welfare, nutrition, and euthanasia and highlights the needs for additional research at all levels of duck production. The purpose of this review is to provide guidelines to raise and house ducks for research as specifically related to industry practices.

The effects of plastic slatted floor and a deep- litter system on the growth performance of hybrid Pekin ducks

This research was conducted to evaluate the effects of plastic slatted floors and a deep-litter system using wood shavings on the growth performance of current commercial hybrid Pekin ducks. A total of 96 Pekin ducks (Star 53) were reared for 42 d. Live weight, live-weight gain, feed consumption, feed conversion ratio, water consumption, and water / feed consumption ratio were investigated as the performance criteria. With the use of plastic slatted floors, the feed conversion rate dropped and the water / feed consumption ratio showed an incline (p<0.05). This is a very favourable result for the poultry industry and growers. The remaining parameters did not change by altering the ground system (p>0.05). Generally, it can be stated that plastic slatted floor use has advantages concerning the performance criteria of the feed consumption ratio and the water / feed consumption ratio in comparison to the deep-litter system. Furthermore, improvement in the feed conversion ratio is known to benefit the overall performance of poultry as well as having a positive economic impact. It should also be noted that as the birds grew, they were visually less stained, which is another important factor determining feather quality. However, this should be further investigated in future research.

A critical review of advancement in scientific research on food animal welfare-related air pollution

Air pollution generates hazardous pollutants that have resulted in safety, health, and other welfare issues of food animals. This paper reviewed scientific research advancement in food animal welfare-related air pollution based on 219 first-hand research publications in refereed journals (referred to as "RPs") over the past nine decades. Scientific studies in this area began in the 1930s. The number of RPs has increased significantly with each decade from the 1960s to the 1980s, then decreased until the 2010s. Twenty-six countries have contributed to this multidisciplinary research. About 52% of the studies were conducted in the U.S. and U.K. Research activities have surged in China since the 2010s. On-farm discoveries in air toxicity that resulted in animal death or injury were all from observational studies. About 75% of the studies were experimental and conducted primarily under laboratory conditions. Ammonia (NH₃) was the main pollutant in 59% of the RPs, followed by dust, hydrogen sulfide (H₂S), bacteria and endotoxins, carbon dioxide (CO₂), carbon monoxide (CO), silo gas, sulfur dioxide (SO₂), and odor. Approximately 23% of RPs reported multiple pollutants in the same study. The most intensively studied animal species were poultry (broilers, hens, turkeys, ducks, and eggs and embryos in 44% of the RPs) and pigs (also 44%), followed by cattle, and sheep and goats. Scientific investigations in this area were driven by the research focuses in the areas of animal agriculture and industrial air pollution. Some major research teams played important roles in advancing scientific research. However, research in this area is still relatively limited. There is a great need to overcome some technical challenges and reverse the trend of decreasing research activities in North America and Europe.

Dietary supplementation of 25-hydroxycholecalciferol increases tibial mass by suppression bone resorption in meat ducks

Leg problems often result from the rapid weight gain and poor bone quality in modern ducks, leading to a high risk of fractures and continuous pain. We hypothesized that improving bone quality in combination with delaying weight gain via a low nutrient density (LND) diet probably reverses these skeletal abnormalities. Studies indicated that 25-hydroxycholecalciferol (25-OH-D₃), a vitamin D₃ metabolite, is effective in treating bone-related disorders. Therefore, Exp. 1 evaluated the effects of 25-OH-D₃ on tibial mass of meat ducks. Male meat ducklings were fed a standard nutrient density diet (containing a regular vitamin regimen) without or with 25-OH-D₃ at 0.069 mg/kg for 35 d. The results showed that 25-OH-D₃ supplementation improved the mineral content, microarchitecture and mechanical properties of tibias, and this companied by a decreased serum bone resorption marker and a concomitant decrement in osteoclast-specific marker genes expression. Subsequently, Exp. 2 was conducted to examine the impacts of 25-OH-D₃ incorporating an LND diet on tibial quality of ducks under 2 different vitamin regimens (regular and high). Ducklings were allocated to a 2 × 2 factorial arrangement with 2 kinds of vitamin premixes and without or with 25-OH-D₃ at 0.069 mg/kg in LND diets. The high premix had higher levels of all vitamins except biotin than the regular premix. The results demonstrated that high vitamin diets exhibited more significant effects than regular vitamin diets on inhibiting bone turnover and increasing minerals deposition. Tibial mineral content, microarchitecture, and strength of birds under the regular vitamin regimen were increased by 25-OH-D₃ supplementation; However, these positive effects were not observed in ducks under the high vitamin regimen. To conclude, 25-OH-D₃ supplementation improves tibial mass by suppressing osteoclast-mediated bone resorption in meat ducks, and this positive impact only was observed in regular but not high vitamin regimen when birds fed an LND diet.

Animal-Based Measures for the On-Farm Welfare Assessment of Geese

Simple Summary

This paper aims to identify animal-based measures of geese welfare for birds raised in commercial meat production systems, and to assess the reliability of these measures. As with other livestock production systems, it is important that geese producers can demonstrate compliance with accepted welfare standards. Presently, there are no welfare measures that have been developed specifically for the geese meat industry. The results showed that plumage dirtiness, twisted wings, and broken/twisted wings are valid and reliable measures of goose welfare and can thus be included in on-farm welfare assessment protocols. Future studies should examine the reliability of other animal-based measures.

Abstract

Currently, no specific animal-based measures (ABMs) protocols are available for geese in commercial meat production systems. Following a critical review of the literature and consultation of experts, seven ABMs, potentially valid and feasible for the on-farm welfare assessment of geese, were identified and then tested in 12 farms in Poland to assess their inter-observer reliability. Two observers conducted the assessment, which was divided into two phases. First, a handling test assessed the human–animal relationship (HAR), and a 100% inter-observer reliability was achieved by the observers when evaluating the attitudes of stockpeople and the reactions of geese to humans. Next, an animal inspection was conducted, and the observers simultaneously and independently visually evaluated 100 randomly selected geese per farm and assessed whether the selected ABMs could be identified. In terms of inter-observer reliability, high correlation coefficients were found for plumage dirtiness (ρ = 0.745; p < 0.01), twisted wings (ρ = 0.890; p < 0.001), and broken/twisted wings (ρ = 0.858; p < 0.001). The results showed that plumage dirtiness, twisted wings, and broken/twisted wings are valid and reliable measures. Further research should address the reliability of ABMs of geese in other types of production systems.

The Influences of Various Housing Systems on Growth, Carcass Traits, Meat Quality, Immunity and Oxidative Stress of Meat-Type Ducks

The present study aimed to investigate the effect of different housing systems on Pekin ducks. A total of 300-day old Pekin ducklings were randomly divided into four experimental groups; the first housed in a closed house (CH), the second in closed house with open yard (HY), the third group in closed house with swimming pool (CHSP) and the fourth in a closed house with swimming pool and yard (HYSP). Results indicated that the HYSP and CHSP produced higher body weight comparing to the other groups. However, the HYSP gave the highest body weight followed by CHSP then HY and CH. The same trend was observed regarding weight gain and feed-conversion ratio (FCR). Moreover, HYSP, HY and CHSP showed higher dressing percentage, breast muscles and thighs and lower abdominal fat than the CH group. Serum protein was significantly higher in HYSP and HY than that of the closed house. While, lipids, cholesterol and triacylglycerol were significantly lower in groups housed in HY than that of CH. Meat cholesterol and triacylglycerol reduced in groups reared in HY. Housing ducklings in yards and using swimming pools significantly improved the general immunity (phagocytic index and activity and differential leucocytes count), and also improved the oxidative stress parameters. In conclusion, results confirmed that housing ducks in a house supplied with yard and swimming pool can improve its productivity, carcass traits, meat quality, blood lipid profile, immunity and antioxidative status.

On-farm welfare assessment of commercial Pekin ducks: a comparison of methods

Although a number of welfare assessment methods have been developed for poultry, none have been evaluated for use in commercial duck farms. The primary objective of the study was to evaluate the inter-rater reliability and relative accuracy of 4 duck welfare assessment strategies. Over 2 experiments, 12 flocks of commercial meat ducks (5,850 to 6,300 ducks/flock) aged 30 to 34 D were evaluated. During experiment 1, six flocks were evaluated using 2 welfare assessment methods: transect walks (TW) and catch-and-inspect (CAI). During TW, 2 observers walked predetermined transects along the length of the house and recorded the number of ducks per transect that were featherless, were dirty, were lethargic, had bloody feathers, had infected eyes, and/or had plugged nostrils or were found dead. During CAI, a total of 150 ducks per flock were corralled and individually evaluated. The same welfare indicators were assessed using both methods. During experiment 2, six flocks were initially evaluated using CAI, TW, and a distance evaluation (DE; a total of 50 ducks per flock evaluated from a walking distance) and then reassessed within 24 h during the loadout (LO) process. Data were analyzed in SAS (version 9.4) to determine the observer and method effects on the incidence of welfare indicators. Interobserver reliability was high (P > 0.05) across methods for most welfare indicators. The assessment method affected the measured outcome variables in both experiments (P < 0.05). CAI resulted in higher estimated incidences of most welfare indicators than TW (experiment 1 and 2) and LO (experiment 2). DE yielded intermediate results compared with other methods (experiment 2). Results obtained using TW and LO were most similar, the only difference being the number of dead birds observed using each method (P < 0.0001). The average time required for CAI, TW, DE, and LO was 2.40 ± 0.004, 1.12 ± 0.02, 1.54 ± 0.001, 3.56 ± 0.006 h, respectively. Bootstrapping analyses showed that the observed welfare indicator prevalence estimates were affected by the number of transects (TW) and number of birds (CAI) sampled.

Study on the morphology and mineralization of the tibia in meat ducks from 1 to 56 d

The objective of this current study was to characterize the basic physiological data on morphological and mineralized properties of the tibia from 1 to 56 days, as well as the interrelationships of body weight (BW) and bone traits for meat ducks. A total of 176 1-d-old ducks was allocated into eight pens and fed with the same diet until the age of 56 d. Eight birds (1 ducks/pen) were randomly selected weekly for measuring BW and tibia characteristics. The BW of duck was increased with age throughout the whole study. Tibial length and width rapidly grew from 1 to 35 d, when it leveled off. The fat-free weight, ash, calcium (Ca) and phosphorus (P) content of tibia increased rapidly from 1 to 42 d and reached its plateau from 42 d onward. Tibial density and tibia-breaking strength increased in a regular manner with age until 42 d. Serum alkaline phosphatase activity was higher between 1 to 7 d in the duck. Regression and ontogenetic scaling analysis showed the age of maximal growth rate in tibia dimension and mineralization was earlier than that in BW; when compared with BW, tibial fat-free weight and tibia-breaking strength increased isometrically, tibia length displayed a negative allometry, and tibial width showed a positive allometric growth. Results indicate that the tibia displayed rapid bone growth (1 to 35 d) and mineralization (1 to 42 d), and alkaline phosphatase (ALP) plays a critical role in the early stage of tibia mineralization of meat duck. Intensive selection for growth rate in ducks has resulted in tibial morphology changes, which represents an interesting compromise of adaptation for increasing BW.

Effects of post-hatch brooding temperature on performance of starter and growing Pekin ducks

An experiment was conducted to investigate the effects of post-hatch brooding temperature on the growth performance of starter Pekin ducks from hatch to 14 D of age and the subsequent growth performance and carcass trait of growing ducks from 15 to 42 D of age. A total of 360 one-day-old male White Pekin ducks were allocated randomly to 6 environment-controlled chambers with ambient temperature set at 26, 28, 30, 32, 34, and 36°C from hatch to 7 D of age, respectively, and then decreased gradually to 26°C at 14 D of age. At 14 D of age, all ducks from all chambers were transferred to a duck barn with ambient temperature maintaining from 26 to 22°C and these birds continued to be raised from 14 to 42 D of age. At 14 D of age, body weight, weight gain, and feed intake decreased linearly or quadratically as initial brooding temperature increased (P < 0.05) and these performance traits were reduced when initial brooding temperature increased to 36°C (P < 0.05). There was no difference in growth performance between ducks fed at brooding temperature regimen starting at 26, 28, 30, and 32°C (P > 0.05). According to broken-line regression, the upper critical temperatures of the initial brooding temperature during the starter period for body weight, weight gain, and feed intake were 31.3, 31.3, and 31.1°C, respectively. On the other hand, the growing ducks brooded initially at 26 or 36°C had lower body weight, weight gain, and feed intake as compared to other birds brooded starting from 28 to 34°C (P < 0.05), but the initial brooding temperature had no effects on carcass traits (P > 0.05). It was concluded that the upper critical temperature of the initial brooding temperature for starter Pekin ducks was 31.3°C and too low initial brooding temperature could lead to growth depression during the subsequent growing period.

Influence of swimming time in alleviating the deleterious effects of hot summer on growing Muscovy duck performance

This experiment was conducted to observe the effects of varying swimming times (ST) of Muscovy ducks, raised in an open-sided house, in alleviating the deleterious effects of high temperature in hotter times of the day in the summer season on growth performance (body weight, average daily gain, feed consumption, and feed conversion ratio), carcass characteristics, body temperature, and some health aspects. We hypothesized that swimming times during the hottest periods of the day would show different performances. To test this hypothesis a total of 180 Muscovy ducklings were randomly distributed into 4 equal groups in a completely randomized design experiment. All groups were raised under similar housing conditions. Birds of the first group (C) were raised in the indoor system and had no access to a swimming pond. While all birds of the second, third, and fourth groups (T1, T2, and T3) had access to a swimming pond during 10:00 to 12:00 h, 12:00 to 14:00 h, and 14:00 to 16:00 h, respectively. The swimming pond (dimensions of 30 m length × 10 m width × 3 m depth with cement floor) was located in the front of the house. Vaccination and medical programs were undertaken according to the different ages under supervision of a licensed veterinarian. The obtained results indicated that swimming during 12:00 to 14:00 h improved (P < 0.05) growth performance, dressed carcass, meat tenderness, lymphocyte, heterophils/lymphocytes ratio, body temperature, and mortality rate of Muscovy ducks. However, bone measurement, plumage conditions, foot pad dermatitis, hock discoloration, breast blisters score, and blood hematocrit values were insignificantly better in the group with access to the swimming pond during 12:00 to 14:00 h. In conclusion, raising ducks during hot conditions in an open-sided house with access to a swimming pond at 12:00 to 14:00 h is highly recommended due to the high BW, better immunity, decreased mortality rate, and low body temperature of ducks which was positively reflected in the health condition.

Integrative analysis of the Pekin duck (Anas anas) MicroRNAome during feather follicle development

BACKGROUND

The quality and yield of duck feathers are very important economic traits that might be controlled by miRNA regulation. The aim of the present study was to investigate the mechanism underlying the crosstalk between individual miRNAs and the activity of signaling pathways that control the growth of duck feathers during different periods. We therefore conducted a comprehensive investigation using Solexa sequencing technology on the Pekin duck microRNAome over six stages of feather development at days 11, 15, and 20 of embryonic development (during the hatching period), and at 1 day and 4 and 10 weeks posthatch.

RESULTS

There were a total of 354 known miRNAs and 129 novel candidate miRNAs found based on comparisons with known miRNAs in the Gallus gallus miRBase. The series of miRNAs related to feather follicle formation as summarized in the present study showed two expression patterns, with primary follicle developed during embryonic stage and secondary follicle developed mainly at early post hatch stage. Analysis of miRNA expression profiles identified 18 highly expressed miRNAs, which might be directly responsible for regulation of feather development. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis suggested that in addition to Wnt and transforming growth factor (TGFβ) signaling pathways, which were widely reported in response to follicle formation, another group of signaling pathways that regulate lipid synthesis and metabolism, such as the phosphatidylinositol signaling system and glycerolipid metabolism and signaling, are also responsible for follicle formation.

CONCLUSION

The highly expressed miRNAs provide a valuable reference for further investigation into the functional miRNAs important for feather development. Lipid synthesis and metabolism related signaling pathways might be responsible for lipid formation on the surface of feather, and should be paid much more attention for their relation to feather quality.

Higher heritabilities for gait components than for overall gait scores may improve mobility in ducks

Background

Genetic progress in selection for greater body mass and meat yield in poultry has been associated with an increase in gait problems which are detrimental to productivity and welfare. The incidence of suboptimal gait in breeding flocks is controlled through the use of a visual gait score, which is a subjective assessment of walking ability of each bird. The subjective nature of the visual gait score has led to concerns over its effectiveness in reducing the incidence of suboptimal gait in poultry through breeding. The aims of this study were to assess the reliability of the current visual gait scoring system in ducks and to develop a more objective method to select for better gait.

Results

Experienced gait scorers assessed short video clips of walking ducks to estimate the reliability of the current visual gait scoring system. Kendall’s coefficients of concordance between and within observers were estimated at 0.49 and 0.75, respectively. In order to develop a more objective scoring system, gait components were visually scored on more than 4000 pedigreed Pekin ducks and genetic parameters were estimated for these components. Gait components, which are a more objective measure, had heritabilities that were as good as, or better than, those of the overall visual gait score.

Conclusions

Measurement of gait components is simpler and therefore more objective than the standard visual gait score. The recording of gait components can potentially be automated, which may increase accuracy further and may improve heritability estimates. Genetic correlations were generally low, which suggests that it is possible to use gait components to select for an overall improvement in both economic traits and gait as part of a balanced breeding programme.

Gait in ducks (Anas platyrhynchos) and chickens (Gallus gallus) - similarities in adaptation to high growth rate

Genetic selection for increased growth rate and muscle mass in broiler chickens has been accompanied by mobility issues and poor gait. There are concerns that the Pekin duck, which is on a similar selection trajectory (for production traits) to the broiler chicken, may encounter gait problems in the future. In order to understand how gait has been altered by selection, the walking ability of divergent lines of high- and low-growth chickens and ducks was objectively measured using a pressure platform, which recorded various components of their gait. In both species, lines which had been selected for large breast muscle mass moved at a slower velocity and with a greater step width than their lighter conspecifics. These high-growth lines also spent more time supported by two feet in order to improve balance when compared with their lighter, low-growth conspecifics. We demonstrate that chicken and duck lines which have been subjected to intense selection for high growth rates and meat yields have adapted their gait in similar ways. A greater understanding of which components of gait have been altered in selected lines with impaired walking ability may lead to more effective breeding strategies to improve gait in poultry.

Summary: Different bird species bred for meat production have adapted their gait in similar ways to handle the extra loads imposed on their legs by larger muscle masses.

Evaluating Pekin duck walking ability using a treadmill performance test

Gait scoring is the most popular method for assessing the walking ability of poultry species. Although inexpensive and easy to implement, gait scoring systems are often criticized for being subjective. Using a treadmill performance test we assessed whether observable differences in Pekin duck walking ability identified using a gait scoring system translated to differences in walking performance. One hundred and eighty ducks were selected using a three-category gait scoring system (GS0 = smooth gait, n = 55; GS0.5 = labored walk without easily identifiable impediment, n = 56; GS1 = obvious impediment, n = 59) and the amount of time each duck was able to sustain walking on a treadmill at a speed of 0.31 m/s was evaluated. The walking test ended when each duck met one of three elimination criteria: (1) The duck walked for a maximum time of ten minutes, (2) the duck required support from the observer's hand for more than three seconds in order to continue walking on the treadmill, or (3) the duck sat down on the treadmill and made no attempt to stand despite receiving assistance from the observer. Data were analyzed in SAS 9.4 using PROC GLM. Tukey's multiple comparison test was used to compare differences in time spent walking between gait scores. Significant differences were found between all gait scores (P < 0.05). Behavioral correlates of walking performance were investigated. Video recorded during the treadmill test was analyzed for counts of sitting, standing, and leaning behaviors. Data were analyzed in SAS 9.4 using a negative binomial model for count data. No differences were found between gait scores for counts of sitting, standing, and leaning behaviors (P > 0.05). In conclusion, the amount of time spent walking on the treadmill corresponded to gait score and was an effective measurement for quantifying Pekin duck walking ability. The test could be a valuable tool for assessing the development of walking issues or the effectiveness of treatments aimed at promoting leg health.

Increased water contamination and grow-out Pekin duck mortality when raised with water troughs compared to pin-metered water lines using a United States management system

Controversy has developed as to whether or not pin-metered water lines or water troughs are more appropriate for Pekin ducks. We hypothesized that water troughs would show improved duck body conditions and environmental quality compared to pin-metered water lines. To test this hypothesis, we housed ducks in 2 barns, one with water lines and one with water troughs. Water troughs were constructed to meet RSPCA guidelines for number and density of ducks and with recently described verandas. Ducks were divided into 4 pens per barn (n=1,000 ducks/pen). The study was then repeated (n=8 pens per water source) in a cross-over design so the barns each contained the opposite water source to the first experiment. We scored the ducks' body condition using an established scoring rubric and analyzed using SAS Proc GLM-Mix as binomial data. Ducks housed with water troughs showed higher (thus worse condition; P<0.001) scores for eyes, nostrils, feather quality, feather cleanliness, and foot pads. We also compared water condition, water quality, and duck mortality using a Student t test for both water sources each week. We found that the water troughs showed higher iron (P<0.001), nitrites (P<0.001), pH (P<0.01), and bacterial growth (P<0.001). The bacterial growth was shown to have higher (P<0.001)E. coli, coliforms, and Staphylococcusin the water troughs. Water lines typically showed no bacterial growth in culture-based assays. Ducks housed with water troughs used greater (P=0.001) volumes of water compared to ducks housed with water lines. Ducks with water troughs also showed a greater percent (P=0.008) mortality at all ages compared to ducks with water lines. These data suggest that water troughs may not be beneficial for duck welfare and could adversely impact both environment and duck or human health.

Differences in hindlimb morphology of ducks and chickens: effects of domestication and selection

Background

Poultry account for the most numerous species farmed for meat and have been subject to intense selection over approximately 60 generations. To assess morphological changes which have occurred in the avian leg due to selection for rapid growth and high meat yields, divergent lines of chicken (Gallus gallus) and duck (Anas platyrhynchos) were studied between 3 and 7 weeks of age. For each line, femoral and tibiotarsal morphology was recorded using computed tomography scanning and tibiotarsal bone quality measures (stiffness, bending stress and porosity) were assessed.

Results

In chicken and duck, divergence in hindlimb morphology has occurred in the commercial meat lines compared to their lighter conspecifics. As expected, the differences were largest between species. Leg development nears completion much earlier in ducks than in chickens. Duck tibiotarsi showed a large degree of lateral curvature, which is expected to affect foot position during swimming and walking, and thus to influence gait. All lines have adapted their tibiotarsal morphology to suit the loading forces they experience; however bone quality was found to be poorer in chickens.

Conclusions

We demonstrate that intensive selection for growth rate in both chickens and ducks has resulted in leg morphology changes, which are likely to influence gait. Ducks represent an interesting compromise of adaptation for efficient locomotion in two media—on land and in water. Some aspects of bone morphology in the duck, such as lateral curvature of the tibiotarsus, may result from adaptation to swimming, which potentially imposes limitations on terrestrial locomotion.

Electronic supplementary material

The online version of this article (doi:10.1186/s12711-015-0166-9) contains supplementary material, which is available to authorized users.

Assessing the waddle: An evaluation of a 3-point gait score system for ducks

Impaired walking ability is an economically important welfare problem that affects poultry raised for meat production, including Pekin ducks. To gain a better understanding of the impacts of walking impairments on duck production, and to identify contributing variables and plausible remedies, an accurate measure of walking ability must first be defined. The viability of a 3-point gait score system for characterizing the walking abilities of Pekin ducks was evaluated. Specifically, we examined whether the qualitative gait score categories corresponded to quantitative gait parameter measures, and evaluated the inter- and intra-rater reliabilities of the gait score system. Commercial Pekin ducks aged 13 to 14 d (14 d; 248 ducks), 20 to 21 d (21 d; 350 ducks), and 30 to 32 d (31 d; 368 ducks), were video recorded and gait scored using a 3-point system (GS0 = best gait; GS2 = poor gait) as they crossed a Tekscan(®) gait analysis system. Gait structure parameters were calculated based on 4 steps made by each duck. The most prominent differences were observed at 21 d and 31 d of age between the ducks with GS0 and GS2, with GS2 scoring ducks walking a shorter total distance, having greater differences in the amount of pressure applied to the right versus left leg, and the amount of time spent standing on 2 feet between steps. Gait score reliabilities were calculated separately for observers who received minimal training (M, N = 10) and those who viewed and discussed the sample cases (V, N = 13). Both groups assessed the gait of ducks from video footage. Inter-rater reliability (Fleiss kappa) was lowest for 14 d old ducks (M: k = 0.47, T: k = 0.62), and best for the 32 d old ducks (V: k = 0.75; T: k = 0.8). Overall, intra-rater reliabilities (Pearson's correlation) were high and were unaffected by the scorer's level of training (M: r = 0.87; V: r = 0.87; t21 = 0.43). The results indicate that a 3-point gait score system is a promising tool for assessing the walking ability of ducks at 21 d of age and older.

Duck gait: Relationship to hip angle, bone ash, bone density, and morphology

The rapid growth meat birds, including ducks, undergo requires skeletal integrity; however, fast growth may not be conducive to adequate bone structure. A relationship likely exists between skeletal changes and duck mobility. Reduced mobility in meat ducks may have impacts on welfare and production. This study examined the relationships among gait score, bone parameters, and hip angle. Commercial Pekin ducks, ages 14 d (n = 100), 21 d (n = 100), and 32 d (n = 100) were weighed and gait scored with a 3-point gait score system by an observer as they walked over a Tekscan gait analysis system. Gait was scored as GS0, GS1, or GS2 with a score of GS0 defined as good walking ability and a score of GS2 as poorest walking ability. Ducks were humanely euthanized, full body scanned using quantitative computed tomography (QCT), and the right femur and tibia were extracted. Leg bones were cleaned, measured, fat extracted, and ashed. QCT scans were rendered to create computerized 3D models where pelvic hip angles and bone density were measured. Statistical analysis was conducted using PROC MIXED with age and gait score in the model. Body weight increased with age, but within an age, body weight decreased as walking ability became worse (P < 0.01). As expected, linear increases in tibia and femur bone width and length were observed as the ducks aged (P < 0.01). Right and left hip angle increased with duck age (P < 0.01). Additionally, ducks with a GS2 had wider hip angles opposed to ducks with a GS0 (P < 0.01). Bone density increased linearly with both age and gait score (P < 0.05). Femur ash content was lowest in 32-day-old ducks and ducks with GS1 and GS2 (P < 0.0001). Tibia ash content increased with age, but decreased as gait score increased (P < 0.001). The observation that right hip angle changed with gait scores merits further investigation into the relationship between duck mobility and skeletal changes during growth.