Effect of Pasture and Feed Additives on Performance and Egg Quality in Ranging Laying Hens
Free-range egg production is rapidly growing in Australia with an estimated retail value market share of 48% (AECL, 2014). Laying hens exposed to pasture range may experience reduced performance, poor enteric health and increased mortality (Ruhnke et al., 2014). In addition, egg quality can also be affected, indicated by the increased number of damaged and misplaced eggs as well as decreased egg shell quality (Kijlstra et al., 2009). These effects may be related to excessive fiber digestion and reduced nutrient uptake. The addition of multi-enzymes or organic acids to free-range layer diets may improve the digestion of nutrients, thus increasing performance, gut health and egg quality. A study was conducted to investigate the effect of range types and feed additives on performance and egg quality of ranging laying hens.
Role of diet on odour emissions from meat chickens
Abatement of odour emissions has become an important consideration to agricultural industries, including poultry production. In order to study the link between diet and odour emissions, an experiment was conducted using twelve Ross 308 broiler chickens. At the age of 22 days, birds of uniform body weight were selected from a total of 288 male birds, adapted to metabolic chambers for six days and fed their respective diets for 15 days. Two treatments were compared using three replicates of two birds per chamber. The two wheat-soy diets were formulated according to the 2007 Ross 308 nutrient specifications for digestible amino acids but they differed in ingredient composition and metabolisable energy content. Thus, Diet A had 13.39 MJ/kg ME and used 60g/kg canola but no corn whereas Diet B contained 12.90 MJ/kg ME and used 150g/kg corn but no canola. The odorous emissions were measured using a Fourier transform infrared spectroscopy. A total of 24 volatile organic compounds were detected and quantified; eight being the major odorous ones: 2,3-butanedione, 2-butanone, dimethyldisulfide, methylmercaptan, 2-butanol, 3-methyl-butanal, phenol and m-cresol. From this pilot study it appears that there is a strong link between diet and odour emissions from broiler chickens.
Demographics and practices of semi-intensive free-range farming systems in Australia with an outdoor stocking density of ≤1500 hens/hectare
Baseline information on demographics and practices on semi-intensive free-range egg farms with an outdoor stocking density of ≤1500 hens/hectare in Australia is presented. Free-range egg production is changing the structure of the egg industry in Australia and a broad variety and tiers of free-range systems have emerged due to lack of concrete legislative standards on outdoor stocking densities in the past. Information was extracted from a pre-existing online free-range poultry survey dataset, consisting of a total of 79 questions related to nutrition, pasture management, welfare and health, animal housing, environmental impact and economics. Forty-one free-range egg farms, with an outdoor stocking density of ≤1500 hens/hectare, were identified in the dataset from all major Australian states. Two types of semi-intensive free-range housing systems were documented: mobile (modified caravan/trailer) housing (56%), and fixed sheds (44%). Seventy-two percent of respondents reported >75% of the hens in the flock used the outdoor range. All respondents reported ingestion of range components by hens in the form of vegetation, insects, stones and grit. Up to 10% mortality was reported by 40% respondents with predation (34%), cannibalism (29%), heat stress (24%) and grass impaction (19.5%) as major causes. Biosecurity on farms was sub-optimal with 8 of the 10 actions implemented by <50% respondents. Customer demand, consumer sentiment and welfare were the major factors for farmers moving into free-range egg production. This study resulted in identification of current practices and key challenges on semi-intensive free-range egg farms. Applied research and communication of results to farmers is highly recommended to ensure optimum health and welfare of free-range laying hens and sustained egg production.
Free-range egg production in Australia: industry trends and challenges
In Australia, free-range egg production is a rapidly growing sector with an estimated grocery market value share of 48% of total table egg production. It can be estimated that around 200 commercial free-range egg producers are currently active. This report reflects the current situation these farmers are facing. Adverse climate conditions and Avian Influenza are a concurrent threat to the freerange egg industry. However, on-range feeding is a common feed strategy performed by up to 47.5% of free-range egg producers. With six states and two territories, no national regulations regarding free range hen housing and egg production are in place. In general, two housing systems can be distinguished: fixed housing and mobile housing. The use of guard animals to protect hens from predators is common. The large variety of farming systems and management procedures is reflected in the variety of challenges free-range hens are facing. In a recent survey, free-range layer producers attributed their losses to predation (42%), heat stress (37%), cannibalism (37%), grass impaction (21%), diseases (21%), and malnutrition (5%). Furthermore, internal and external parasites can be considered as widely prevalent. Producers identified that research should be conducted in welfare (52%), pasture management (54%), nutrition (44%), bird health (44%), housing (40%), and economics (29%). With those demands currently under investigation, Australia can be considered as highly active in the field of applied research focusing on free range-egg production.
Performance, egg quality and liver lipid reserves of free-range laying hens naturally infected with Ascaridia galli
A study was conducted to determine the performance, egg quality, and liver lipid reserves of laying hens exposed to ranges contaminated with Ascaridia galli. Sixteen-week-old Lohmann Brown laying hens (n = 200) were divided into 4 treatments with 5 replicates containing 10 hens per pen. Hens of treatment 1 [negative control (NC)] ranged on a decontaminated area, and hens of treatments 2 (low infection) and 3 (medium infection) ranged on areas previously contaminated by hens artificially infected with 250 and 1,000 embryonated A. galli eggs, respectively. The hens of treatment 4 [positive control (PC)] ranged on areas previously contaminated by hens artificially infected with 2,500 embryonated A. galli eggs, and in addition these hens were orally inoculated with 1,000 embryonated eggs. Results indicated that hens of the medium infection group had a higher number of intestinal A. galli worms and A. galli eggs in the coprodeum excreta (43.9 ± 4.0 and 3,437 ± 459 eggs/g) compared to hens of the low infection group (23.8 ± 4.0 and 1,820 ± 450 eggs/g) (P < 0.01) and similar worm counts to PC hens (34.4 ± 4.0 and 2,918 ± 474) (P > 0.05). Egg production, egg mass, feed intake, and feed conversion ratio (FCR) were not affected by A. galli infection (P > 0.05). Egg quality parameters (egg weight, shell reflectivity, shell weight, shell thickness, shell percentage, shell breaking strength, deformation, albumen height, Haugh unit, and yolk score) were not affected by A. galli infection (P > 0.05). Highly infected hens had lower liver lipid content (2.72 ± 0.51 g) compared to uninfected hens (4.46 ± 0.58 g, P < 0.01). The results indicate that exposure to ranges contaminated with A. galli resulted in infection of the ranging hens, but this did not affect egg production or egg quality. Infection with A. galli lowered the liver lipid reserves of the host significantly, suggesting infected hens use more energy reserves for maintenance and production.
Detection of Ascaridia galli in free-range laying hens
Reliable methods for detection of A. galli infection using excreta egg count (EEC) and ELISA assays to determine A. galli specific IgY levels in serum and yolk samples were compared from hens infected naturally and artificially. Artificially infected hens were used to generate samples for analysis of preferred detection methods and to generate contaminated ranges for use in the naturally acquired infection study in which Lohmann Brown hens (n = 200) at 16 weeks of age were randomly assigned to four treatments with five replicate pens. Hens of negative control (NC) ranged on a decontaminated area, hens of low infection, medium infection and positive control (PC) ranged on the areas previously contaminated by hens artificially infected with 250, 1000 and 2500 A. galli eggs/hen, respectively. Additionally, hens of PC were orally infected with 1000 A. galli eggs/hen. Anti A. galli antibody levels in hen serum (SIgY) and yolk (YIgY) were measured before range access, and 2, 7 and 12 weeks after access to the contaminated ranges. In a natural infection study, eggs were detected in the excreta of all hens 4 weeks after range access, with the exception of NC in which no eggs were detected. EEC increased to reach maximum value (2204 ± 307 eggs/g) after 11 weeks of range access and then declined at 12 weeks (905 ± 307eggs/g) (p < 0.01). While SIgY OD values were not different in hens between any groups before range access, after 2 weeks, both SIgY and YIgY gradually increased in hens of PC (1.17 ± 0.03 and 0.88 ± 0.04) and medium infection (1.07 ± 0.03 and 0.96 ± 0.04) compared to low infection (0.38 ± 0.03 and 0.29 ± 0.04) (p < 0.01) and NC. After 12 weeks, SIgY were similar in hens of PC, medium and low groups whereas YIgY was higher in hens of low infection group (p < 0.01). Sensitivity of the serum and egg yolk antibody levels assay to detect A. galli infection was 100% and 96%, respectively, whereas the pooled EEC method yielded a sensitivity of 93%. The results of this study suggest that hens naturally infected with A. galli produce both SIgY and YIgY at different levels depending on the infection intensity and duration of exposure which allows the diagnosis of prior infection or early diagnosis of current infection. Use of the practical and non-invasive method of yolk sample analysis for detecting IgY can be just as informative as using serum samples to detect A. galli infection.
Ascaridia galli challenge model in laying hens
Ascaridia galli is one of the most prevalent helminths in free-range laying hens. This study was conducted to establish a reliable infection model for A. galli in laying hens. Materials and methods : A total of 20 Lohmann brown hens of 19 weeks age were assigned to 4 treatment groups (n=5 per group). Hens of group 1 were orally inoculated with 1000 A. galli eggs stored at 26°C, group 2 with 1000 A. galli eggs stored at 4°C and transferred to 26°C prior to inoculation. Hens were infected 3 times over a week period. Hens of group 3 were orally inoculated with 500 A. galli eggs stored at 26°C, 6 times over 2 week period. Hens in group 4 were infected with adult A. galli via cloaca. Intestinal immature worms were counted from 2 hens from each group after slaughter at 2 weeks post infection (p.i).Excreta was collected and analysed for A. galli eggs at 8 and 14 weeks p.i.. Blood was collected to examine A. galli specific antibodies and intestinal A. galli worms were counted at 16 weeks p.i. results: Hens in group 3 had the highest A. galli worm counts (P<0.001) after slaughter at 16 weeks p.i. compared to other groups. Excreta A. galli egg counts were highest in group 1 and 3 (P=0.02). Serum antibodies among the 3 orally infected groups was similar, but were higher than in hens of group 4 (P<0.01). conclusion: Thus, The method either of inoculating hens orally with 500 A. galli eggs 6 times over 2 weeks period, or with 1000 A. galli eggs 3 times over a week period was the most reliable method tested.
Impact of on-range choice feeding with black soldier fly larvae (Hermetia illucens) on flock performance, egg quality, and range use of free-range laying hens
Semi-intensive free-range farm systems are common in Australia, and these systems frequently practise on-range feeding. The objective of this study was to investigate the benefit of on-range choice feeding on flock performance, egg quality, and range use of free-range laying hens using black soldier fly larvae (Hermetia illucens, BSF). A total of 160 mature ISA brown laying hens, previously determined to range daily, were allocated to a control group (control) or a treatment group (BSF) with various replicates depending on the parameter investigated. All hens were fed ad libitum indoors with a wheat-soy based diet formulated according to breed requirements. Black soldier fly hens were offered dried BSF larvae ad libitum on the range. Body weight, feed intake, BSF intake, egg production, feed conversion ratio, internal and external egg quality parameters, and individual range use using radio-frequency identification (RFID) technology was evaluated. Black soldier fly hens consumed on average 15 ± 1.7 g BSF larvae/hen per day. There were no differences between BSF and control hens for any of the performance parameters obtained (P > 0.05). Egg weight, shell weight, and shell thickness of eggs from BSF hens were significantly lower (P = 0.003, P = 0.001, and P = 0.004, respectively) than those of eggs from control hens. Egg yolk colour was significantly paler in eggs from BSF hens (P < 0.001). No significant ranging differences between the BSF and control hens were observed (P > 0.05) except for BSF hens showing longer total maximum time for a single visit to the range (P = 0.011). In conclusion, the average intake of BSF larvae indicated a good level of acceptance. Feed formulation should be adjusted for the intake of the choice fed source. The impact of choice-feeding on range use was minor.
Welfare issues affecting free-range laying hens
Free-range laying hen production systems take a step down a different path in the progression of domestic chicken farming. They take hen groups away from intensive, environmentally controlled, indoor housing and put them back outdoors to provide flocks with more natural, minimally controlled surroundings. Consumers prefer the concept of free-range production, particularly in countries where weather allows outdoor access for most of the year (e.g. Australia, Denmark, the United Kingdom), as these systems are viewed as more natural and ethical (Schröder and McEachern, 2004). Free-range systems are thus rapidly increasing in popularity to meet consumer demand. However, highly productive modern genotypes, selected for cage production, are harder to manage in large flocks and outdoor environments with limited control of environmental conditions. Research into the behaviour, health and welfare of birds in non-cage environments has increased in recent years. Unfortunately, in some cases, a high risk of poor outcomes for hens kept in non-cage and especially free-range conditions has been identified (Fossum et al., 2009; Sherwin et al., 2010; Elson, 2015; Weeks et al., 2016). To sustainably improve free-range housing and management, we must understand how hens behave in these systems, the welfare challenges they face and what modifications will, in practice, adequately address hens' needs.
Laying hens exposed to Ascaridia galli contaminated areas: impact on performance and egg quality
The prevalence of Ascaridia galli infection has increased in free-range laying hens in Europe (Thapa et al.,2015).This is a cause of concern in Australia, where the poultry industry is rapidly moving towards free-range egg production and the impact of infection on nutrient absorption and performance is unknown. It is important to monitor the performance and egg quality of laying hens infected with A.galli to develop effective control measures in the future. Two studies were conducted to investigate performance and egg quality of laying hens either artificially or naturally infected with A. galli. Experiments were conducted each using 200 Lohmann Brown laying hens allocated to one of four treatments with five replicates of 10 hens per pen.In Experiment 1, hens allocated to Treatment 1 (Control) were routinely dewormed using levamisole (4mL per bird).