Zukunftslabor Agrar

The poultry industry is an important and still growing sector in many parts of the world. For ethical reasons and due to increased consumer awareness for animal welfare in production animals, it is of importance to establish a reliable and objective test system for monitoring and improving health and welfare. During the rearing process, broiler chickens are exposed to numerous potential stressors and management interventions (e.g. weighing of individual animals, pre-slaughter fasting and capture processes), but assessing the level of stress perceived by the animals entirely through behavioral observations can be challenging. Monitoring stress-related physiological markers, such as glucocorticoids, can be an accurate and presumably more objective addition. To avoid additional stressors induced by blood collection, a non-invasive approach using urofecal samples is advisable. However, a thorough validation is needed to establish a suitable test system for measuring stress hormone levels, including potential effects of the time of day of collection or the time that has elapsed since defecation.

Therefore, the aim of this study was to test the stability of urofecal glucocorticoid metabolites (ufGCM) post defecation, to determine time of day effects on ufGCM levels, and to investigate the effect of standard management procedures on ufGCM concentrations in broiler chickens.

Our results revealed a time window of 4 hours in which fecal samples from broilers can be collected without major alterations to the ufGCM concentrations. In this regard, a ‘fecal box’ proved useful for collecting uncontaminated fresh samples. The time of day of sample collection did not influence ufGCM concentrations significantly. Moreover, the used assay proved to be sensitive enough to detect even small and short-lasting activations of the HPA axis induced by handling, confinement, and fasting. Thus, the system used can be a powerful and easy to apply tool in a chicken production setup for assessing stress as a marker of welfare in commercially housed broiler chickens, which in the long-term can also improve production, particularly with regard to process quality.

Insufficient light conditions are discussed in reference to the occurrence of behavioral disorders, particularly feather pecking in turkeys. In order to ban the beak trimming in turkey husbandry, the light conditions for turkeys need to be improved. In a first step, the current state of lighting conditions in representative turkey barns in north-east Germany were determined. This included e.g. recording installed light sources, including light spectrum, light intensity, and frequency. Additionally, the possibilities for influencing the lighting conditions in the barns were investigated, e.g. dimming of lamps and daylight exposure. Light measurements were conducted in 17 barns, including both naturally ventilated and mechanically ventilated barns with 2 different spectroradiometers (BTS2048-VL and BTS256-EF, Gigahertz Optic). About 75 different measuring points were recorded for each barn, about 60cm above the ground each measurement included mean of 10 measured values, integration time was 100ms. In the examined barns, fluorescent lamps (10x) and LEDs (7x) were installed and three of each were dimmable. In barns with LED lighting, emissions occurred between 400-780nm at each wavelength, so the artificial light spectrum of the LEDs did not contain a UV-A component. With fluorescent lamps, visible light is generated, inter alia, by the conversion of UV light in a fluorescent layer of the lamp, so a small amount of UV radiation (around 360nm) was measurable in the light spectrum. However, fluorescent lamps cannot achieve a daylight-like spectrum, as they emit a narrowband light spectrum characterized by peaks in three color ranges, and thus do not fulfill the light requirements of turkeys. When green blinds were used, the transmission of green wavelengths was enhanced, leading to a spectral shift and, consequently, a potential alteration in color perception by the turkeys. The measured fluorescent lamps may have been perceived as flickering by turkeys because the measured frequency was 100 Hz, thus below the flicker fusion frequency (FFF) of poultry. Light intensities varied significantly at the same dimming setting, making it challenging to make recommendations for light reductions based on dimming settings. For turkeys, the low frequencies (100 Hz) as well as the limited spectrum in artificial light and partially monochromatic light caused by green blinds, which supports false color vision, can trigger stress and be risk factors for behavioral disorders.

Behavioural disorder, turkey, lighting, flicker fusion frequency, UV-light

According to the National Emission Ceilings (NEC) Directive ammonia (NH3) emissions in Germany must be reduced by 29% by 2030 compared to 2005. In order to comply with this limit value, the revised German General Administrative Regulation to the Federal Immission Control Act (Technical instructions for air pollution control; TA-Luft) demands a 70% reduction in ammonia emissions for forced-ventilation poultry houses with a capacity of 40,000 animal places (AP) or more. Poultry houses with a capacity of 30,000 to 40,000 AP must reduce their ammonia emissions by 40%. Technical solutions are available but due to high costs and the poor carbon footprint of the technical solutions, other options are needed. As ammonia emissions emerge from the litter, affecting the animal welfare and health, the bedding material plays a key role in reducing ammonia emissions from the litter. Therefore, a new straw pellet including sodiumbisulfate (SBS) was tested on 2 commercial broiler farms during 3 cycles from January to August 2023 with a total of 234,900 Ross 308 broilers. Both farms had two identical poultry houses. The animals were kept for 42 days. Litter management followed standard recommendations with removing the bedding and cleaning the barn between each cycle. The international VERA test protocol for animal husbandry and management systems was used as the basis for the measurement planning (VERA 2018). Following a case and control method, one barn on each farm was littered with 1.2 kg/m² straw pellets (control) and the other barn was littered with 1.5 kg/m² straw pellets including about 20 % SBS. Case and control barns alternated between each run. Ammonia emissions were determined by FTIR analysis and by the volume flow rate of the poultry houses. Average mortality rate was 2 % over each production cycle. The average feed conversion ratio was 1.48 kg/kg in both, case and control. The use of straw pellets with SBS reduced ammonia emissions by 58.2 % compared to conventional straw pellets. The recovery rates for nitrogen of 106.4 % support these results. In relation to the TA-Luft the ammonia reduction target was achieved with 85 %. In order to complete the VERA test protocol, the tests are ongoing with an expected completion in March 2024.