In modern animal husbandry, stress can be viewed as an automatic response triggered by exposure to adverse environmental conditions. This response can range from mild discomfort to severe consequences, including mortality. The poultry industry, which significantly contributes to human nutrition, is not exempt from this issue. Although genetic selection has been employed for several decades to enhance production output, it has also resulted in poor stress resilience. Stress is manifested through a series of physiological reactions, such as the identification of the stressful stimulus, activation of the sympathetic nervous system and the adrenal medulla, and subsequent hormonal cascades. While brief periods of stress can be tolerated, prolonged exposure can have more severe consequences. For instance, extreme fluctuations in environmental temperature can lead to the accumulation of reactive oxygen species, impairment of reproductive performance, and reduced immunity. In addition, excessive noise in poultry slaughterhouses has been linked to altered bird behaviour and decreased production efficiency. Mechanical vibrations have also been shown to negatively impact the meat quality of broilers during transport as well as the egg quality and hatchability in hatcheries. Lastly, egg production is heavily influenced by light intensity and regimens, and inadequate light management can result in deficiencies, including visual anomalies, skeletal deformities, and circulatory problems. Although there is a growing body of evidence demonstrating the impact of environmental stressors on poultry physiology, there is a disproportionate representation of stressors in research. Recent studies have been focused on chronic heat stress, reflecting the current interest of the scientific community in climate change. Therefore, this review aims to highlight the major abiotic stressors in poultry production and elucidate their underlying mechanisms, addressing the need for a more comprehensive understanding of stress in diverse environmental contexts.

This study investigated the impact of feeding systems on the determination of enteric methane (CH₄) emissions factor in cattle. Real-time feed intake data, a crucial CH₄ conversion rate (Y_m value) parameter, were obtained using a roughage intake control (RIC) unit within a smart farm system. Greenhouse gas (GHG) emissions, including CH₄ and carbon dioxide (CO₂), from Holstein steers were monitored using a GreenFeed (GF) 344 unit. The results revealed satisfactory body weight (383 ± 57.19 kg) and daily weight gain (2.00 ± 0.83 kg), which are crucial factors. CO₂ production exhibited positive correlations with the initial body weight (r = 0.72, p = 0.027), feed intake (r = 0.71, p = 0.029), and feed conversion ratio (r = 0.69, p = 0.036). Five different emission factors (EFs), EF_A (New Equation 10.21A) and Equation 10.21 (EF_B, EF_C, EF_D, and EF_E), were used for GHG calculations following the Intergovernmental Panel on Climate Change (IPCC) Tier 2 approach. The estimated CH₄ EFs using these equations were 69.91, 69.91, 91.79, 67.26, and 42.60 kg CH₄/head/year. These findings highlight the potential for further exploration and adoption of smart farming technology, which has the potential to enhance prediction accuracy and reduce the uncertainty in Y_m values tailored to specific countries or regions.

Journal of Animal Science and Technology (JAST) is a peer-reviewed, open access journal publishing original research, review articles and notes in all fields of animal science. Topics covered by the journal include: genetics and breeding, physiology, nutrition of monogastric animals, nutrition of ruminants, animal products (milk, meat, eggs and their by-products) and their processing, grasslands and roughages, livestock environment, animal biotechnology, animal behavior and welfare.