Most experimental studies on animal stress physiology have focused on acute stress, while chronic stress, which is also encountered in intensive dairy cattle farming–e.g. in case of lameness–, has received little attention. We investigated heart rate (HR) and heart rate variability (HRV) as indicators of the autonomic nervous system activity and fecal glucocorticoid concentrations as the indicator of the hypothalamic–pituitary–adrenal axis activity in lame (with locomotion scores 4 and 5; n = 51) and non-lame (with locomotion scores 1 and 2; n = 52) Holstein-Friesian cows. Data recorded during the periods of undisturbed lying–representing baseline cardiac activity–were involved in the analysis. Besides linear analysis methods of the cardiac inter-beat interval (time-domain geometric, frequency domain and Poincaré analyses) non-linear HRV parameters were also evaluated. With the exception of standard deviation 1 (SD1), all HRV indices were affected by lameness. Heart rate was lower in lame cows than in non-lame ones. Vagal tone parameters were higher in lame cows than in non-lame animals, while indices of the sympathovagal balance reflected on a decreased sympathetic activity in lame cows. All geometric and non-linear HRV measures were lower in lame cows compared to non-lame ones suggesting that chronic stress influenced linear and non-linear characteristics of cardiac function. Lameness had no effect on fecal glucocorticoid concentrations. Our results demonstrate that HRV analysis is a reliable method in the assessment of chronic stress, however, it requires further studies to fully understand the elevated parasympathetic and decreased sympathetic tone in lame animals.

In this narrative review, the authors summarise the relationship between stress and behaviour and how dairy cattle cope with stressors. Based on the available literature, the most common stressors in intensive dairy cattle farming, such as pain, disease, heat stress, poor comfort caused by technology, and social stress, are surveyed. The authors describe how these stressors modify the behaviour of dairy cattle, influencing their feeding patterns, social interactions, and overall well-being. Additionally, the review explores the effectiveness of various coping mechanisms employed by dairy cattle to mitigate stress, including physiological adaptations and behavioural responses. This review is a valuable resource for understanding and grading stress in dairy cattle through behavioural reactions. Elucidating the intricate interplay between stressors and behaviour offers insights into potential interventions to improve animal welfare and productivity in dairy farming. Furthermore, this review highlights areas for future research, suggesting avenues for more comprehensive behavioural studies to enhance our understanding of stress management strategies in dairy cattle.

The non-therapeutic use of antimicrobials in poultry production contributes to the spread of drug-resistant pathogens in both birds and humans. Antibiotics are known to enhance feed efficiency and promote the growth and weight gain of poultry. New regulatory requirements and consumer preferences have led to a reduced use of antibiotics in poultry production and to the discovery of natural alternatives to antibiotic growth promoters. This interest is not only focused on the direct removal or inhibition of causative microorganisms but also on the prevention of diseases caused by enteric pathogens using a range of feed additives. A group of promising feed additives is composed of short- and medium-chain fatty acids (SCFAs and MCFAs) and their derivatives. MCFAs possess antibacterial, anticoccidial, and antiviral effects. In addition, it has been proven that these acids act in synergy if they are used together with organic acids, essential oils, or probiotics. These fatty acids also benefit intestinal health integrity and homeostasis in broilers. Other effects have been documented as well, such as an increase in intestinal angiogenesis and the gene expression of tight junctions. The aim of this review is to provide an overview of SCFAs and MCFAs as alternatives to antibiotic growth promoters and to summarize the current findings in the literature to show their possible benefits on production, meat quality, and gut health in poultry.

The objectives of this study were to explore changes of rumination time and reticuloruminal pH and temperature of dairy cows and heifers (means ± standard deviation; age = 5.8 ± 1.9; parity = 2.7 ± 1.4; body condition score = 3.2 ± 0.2) with eutocic (EUT, n = 10) and dystocic calving (DYS, n = 8). The recording period lasted from 3 d before calving until 7 d in milk. For the comparison of rumination time and reticuloruminal characteristics between groups, time to return to baseline (the time interval required to return to baseline from the delivery of the calf) and area under the curve (AUC; both for prepartum and postpartum periods) were calculated for each parameter. Rumination time decreased from baseline 28 h before calving both for EUT and DYS cows; after 20 h before calving, it decreased to 32.4 ± 2.3 and 13.2 ± 2.0 min/4 h between 8 and 4 h before delivery in EUT and DYS cows, respectively, and then it decreased below 10 and 5 min during the last 4 h before calving. Until 12 h after delivery, rumination time reached 42.6 ± 2.7 and 51.0 ± 3.1 min/4 h in DYS and EUT dams, respectively; however, AUC and time to return to baseline suggested lower rumination activity in DYS cows than in EUT dams for the 168-h postpartum observational period. Reticuloruminal pH decreased from baseline 56 h before calving both for EUT and DYS cows, but did not differ between groups before delivery. Reticuloruminal pH showed a decreasing tendency and clear diurnal variation after calving for both EUT and DYS cows, with slightly higher AUC values in DYS cows. In DYS cows, reticuloruminal temperature decreased from baseline 32 h before calving by 0.23 ± 0.02°C, whereas in EUT cows such a decrease was found only 20 h before delivery (0.48 ± 0.05°C). The AUC of reticuloruminal temperature calculated for the prepartum period was greater in EUT cows than in DYS cows. During the first 4 h after calving, reticuloruminal temperature decreased from 39.68 ± 0.09 to 38.96 ± 0.10°C and from 39.80 ± 0.06 to 38.81 ± 0.08°C in EUT and DYS cows, respectively, and reached baseline levels after 35.4 ± 3.4 and 37.8 ± 4.2 h after calving in EUT and DYS cows, respectively. Based on our results, continuous monitoring of changes in rumination time and reticuloruminal temperature seems to be promising in the early detection of cows with a higher risk of dystocia. Depressed rumination activity of DYS cows after calving highlights the importance of the postpartum monitoring of cows experiencing difficulties at calving. The effect of dystocia on postpartum reticuloruminal pH was not pronounced.

Welfare aspects of obstetrical assistance were studied in multiparous Holstein-Friesian cows (n=176) with (1) unassisted calving in an individual pen (UCIP; n=42), (2) unassisted calving in a group pen (UCG; n=48), (3) assisted calving with appropriately timed obstetrical assistance (ACAP; n=50), and (4) assisted calving with inappropriately timed (premature) obstetrical assistance (ACIN; n=36). Duration of the stages of calving, the prevalence and the degree of dystocia, stillbirth ratio, newborn calf vitality, and the occurrence of postpartum health problems (i.e., retained placenta and vulvovaginal laceration) were recorded. The time from amniotic sac and hooves appearance to birth and the total duration of calving (from the onset of calving restlessness to delivery) were shorter for UCG cows than for any other groups. The overall incidence of dystocia was 31.3% in the calvings studied. The prevalence of dystocia was below 10% in cases of unassisted calvings. The proportion of severe dystocia was higher in ACIN cows than in ACAP cows (47.2 vs. 12.0%, respectively). The prevalence of stillbirths was the highest in ACIN calvings (22.2%), followed by ACAP, UCI, and UCG cows (8.0, 4.8, and 0.0%, respectively). The ACIN calves had lower vitality scores than calves born from ACAP, UCG, and UCIP dams immediately after delivery and 24h after birth. Although ACAP calves had lower vitality scores than UCG and UCIP calves at birth, a delayed recovery of vitality was mirrored by satisfactory vitality scores 24h after birth. Retained placenta and vulvovaginal laceration occurred more often with assisted dams (i.e., ACAP and ACIN animals) compared with UCIP cows with the highest prevalence in ACIN cows. In UCG cows, no injuries occurred in the vulva or vagina, and we noted only 4 cases of retained placenta (8.3%), proportions lower than in cows with unassisted calving in the maternity pen. Our results suggest that calving in a group might have benefits over calving in an individual pen in terms of calving ease, duration of the delivery process, and postpartum health of the dam vitality of her offspring. Premature obstetrical assistance leads to a high prevalence of dystocia, impairs postpartum health of the dam, and poses a potential risk to calf survival.

In this study, upper critical values of the temperature-humidity index (THI) were determined in Holstein bull calves (n = 16) based on noninvasive physiological variables. Meteorological and animal-based data were recorded for a 4-d period following a 24-h habituation. The estimated upper critical THI values based on the assessment of respiratory rate, rectal temperature, ear temperature, heart rate, and salivary cortisol concentrations were 82.4, 88.1, 83.0, 78.3, and 88.8, respectively. We inferred that welfare of young calves may be compromised above a THI of 78 and that calves experience significant heat stress above a THI of 88. Based on the present findings, upper critical THI should be considered to minimize the duration of impaired welfare during summer heat stress episodes.