Behavioural reactivity of ewes and lambs during partial and total social isolation

Chronophysiology of domestic animals

This review highlights recent findings on biological rhythms and discusses their implications for the management and production of domestic animals. Biological rhythms provide temporal coordination between organs and tissues in order to anticipate environmental changes, orchestrating biochemical, physiological and behavioural processes as the right process may occur at the right time. This allows animals to adapt their internal physiological functions, such as sleep-wake cycles, body temperature, hormone secretion, food intake and regulation of physical performance to environmental stimuli that constantly change. The study and evaluation of biological rhythms of various physiological parameters allows the assessment of the welfare status of animals. Alteration of biological rhythms represents an imbalance of the state of homeostasis that can be found in different management conditions.

Temporary sensory separation of lamb groups from ewes affects behaviors and serum levels of stress-related indicators of small-tailed Han lambs

Under the current meat sheep breeding system, newborn lambs usually live with their mothers until weaning, and in daily management, they often need to be separated from their ewes for a short period due to dehorning, disease treatment, etc. Such short-term separation was considered to be a high-intensity stress for the lambs. This study aimed to explore the effects of 1 h sensory separations on behaviors and the concentration of stress-related indicators of small-tailed Han lambs. Lambs were assigned to four groups: auditory, visual, and tactile separation (AVT) group; visual and tactile separation (VT) group; tactile separation (T) group; and control (C) group. Then they were separated from their mothers for one hour on postnatal days 14, 21, 28, 35 and 42. Results showed the separated lambs (AVT, VT, and T groups) spent less time lying down relaxing and more time looking around, exploring, vocalizing, and attempting to escape (P < 0.05). Lambs separated by lack of tactile contact only exhibited the most escaping and moving behavior. Twin-born lambs showed less moving, escaping, and vocalizing than single-born lambs (P < 0.05). The separation also led to a rise in serum globulin levels and a decrease in tetraiodothyronine. In conclusion, this study showed that temporary 1 h ewe-lamb separations could affect behaviors and the serum levels of stress indicators of lambs. The behavioral responses were more obvious when lambs were separated by lack of tactile contact only, and in single-born lambs. It can conclude that indicated that when lambs need to be temporarily separated from ewes in daily management production, it would be better to let them stay together with their littermates, and make them avoid hearing or seeing the ewes, such management may partially reduce the separation stress, thereby improving the welfare and breeding efficiency of sheep.

Animal-Based Indicators for On-Farm Welfare Assessment in Sheep

Simple Summary

As we keep and use sheep, we need to be able to assess their welfare and deal with welfare problems as they arise. To assess welfare, a comprehensive protocol based on valid and feasible indicators is needed. The aim of this study was to review the scientific literature and identify protocols and indicators for assessing the welfare of sheep. We identified promising protocols, well-known and established indicators, such as lameness or body condition score, as well as novel indicators that still need to be evaluated to prove their validity, such as pruritic behaviour or resting time. This review provides a starting point for the development of valid and feasible on-farm protocols using animal-based indicators to assess sheep welfare.

Abstract

The value society assigns to animal welfare in agricultural productions is increasing, resulting in ever-enhancing methods to assess the well-being of farm animals. The aim of this study was to review the scientific literature to obtain an overview of the current knowledge on welfare assessments for sheep and to extract animal-based welfare indicators as well as welfare protocols with animal-based indicators. By title and abstract screening, we identified five protocols and 53 potential indicators from 55 references. Three out of the five protocols include animal-based as well as resource-based indicators. All of them were assessed as being practicable on-farm but lacking reliability. Some of the single indicators are endorsed by the literature and widely used in the field like assessment of behaviour, lameness or body condition score. Others (e.g., Faffa Malan Chart FAMACHA©, dag score or pain assessment) are regularly mentioned in the literature, but their reliability and usefulness are still subject of discussion. Several indicators, such as pruritic behaviour, eye condition, lying time or tooth loss are relatively new in the literature and still lack evidence for their validity and usefulness. This literature review serves as a starting point for the development of valid and practicable welfare protocols for sheep.

Individual differences in behavior and heart rate variability across the preweaning period in the domestic horse in response to an ecologically relevant stressor

The study of individual differences in behavior and physiology has attracted considerable interest among behavioral biologists. Important questions include how early in life such differences emerge and to what extent they remain stable across development. Due to the demanding nature of longitudinal studies, there is still a lack of information on this in mammals, especially in large, long-lived species. Our aim in this study was to look for stable individual differences in behavior and physiology during early development in the domestic horse and for correlations between the two parameters. We tested 30 Azteca-breed foals kept under standard conditions by briefly separating them from their mother in four repeated tests beginning at the first postnatal week until the foals were six months old, before they were weaned. Individual differences in behavior and heart rate variability of foals in response to brief maternal separations were consistent and were correlated from a very early age. These findings contribute to an understanding of the expression of individual differences in physiology and behavior from a developmental perspective and may help in the future selection of horses for functional contexts that require different levels of reactivity, thereby contributing to horse welfare and to human safety and economy.

Laterality as an indicator of emotional stress in ewes and lambs during a separation test

We assessed motor laterality in sheep to explore species-specific brain hemi-field dominance and how this could be affected by genetic or developmental factors. Further, we investigated whether directionality and strength of laterality could be linked to emotional stress in ewes and their lambs during partial separation. Forty-three ewes and their singleton lambs were scored on the (left/right) direction of turn in a y-maze to rejoin a conspecific (laterality test). Further, their behavioural response (i.e. time spent near the fence, vocalisations, and activity level) during forced separation by an open-mesh fence was assessed (separation test). Individual laterality was recorded for 44.2% ewes (significant right bias) and 81.4% lambs (equally biased to the left and the right). There was no significant association in side bias between dams and offspring. The Chi-squared test revealed a significant population bias for both groups (p < 0.05). Evolutionary adaptive strategies or stimuli-related visual laterality may provide explanation for this decision-making process. Absolute strength of laterality (irrespective of side) was high (Kolmogorov-Smirnov test, dams: D = 0.2; p < 0.001; lambs: D = 0.36, p < 0.0001). The Wilcoxon test showed that lateralised lambs and dams spent significantly more time near each other during separation than non-lateralised animals (p < 0.05), and that lateralised dams were also more active than non-lateralised ones. Arguably, the lateralised animals showed a greater attraction to their pair because they were more disturbed and thus required greater reassurance. The data show that measures of laterality offer a potential novel non-invasive indicator of separation stress.