Lying behaviour of housed and outdoor-managed pregnant sheep

Abstract

Little is known about the lying behaviour of sheep despite its high value in supporting productivity and welfare in other livestock. The aim of this experiment was to investigate the lying behaviour of pregnant sheep and test for the effects of biological and physical factors on lying behaviour. Data for 96 Mule ewes managed to lamb indoors, and 80 predominantly Welsh Mountain ewes managed to lamb at grass were used for the study. Acceleration values were collected for the two flocks from HOBO Pendant G accelerometers (Onset Computer Corporation, Bourne, MA) fitted vertically to the outside of the rear right leg and set to record at 1-min intervals for at least 14 d prior to parturition.Ewes were simultaneously recorded using video equipment to identify lambing and to verify predictions of lying (total lying time, mean lying bout duration and mean numbers of lying bouts) using 10 randomly selected ewes from the indoor flock on day -10 prior to lambing. Linear regression was used to evaluate predicted behaviours with video footage. Measures of lying (mean daily lying time, mean lying bout duration and mean daily lying bouts) were calculated for all ewes using averages taken across days -10, -9 and -8 prior to lambing and linear regression was used to test for effects of independent variables (pregnancy scan result (single-or twin-bearing), ewe age, ewe BCS, lambing ease, lamb sex and lamb birth weight) on each measure of lying. Predictions of total lying time (R 2 ≥ 0.99; P > 0.05 for slope = 1, intercept = 0), mean lying bout duration (R 2 ≥ 0.99; P > 0.05 for slope = 1, intercept = 0) and mean number of lying bouts (R 2 ≥ 0.98; P > 0.05 for slope = 1, intercept = 0) were strongly associated with video footage (P < 0.001), demonstrating that a 1-min sampling interval provides reliable estimates of ewe lying behaviours. Significant associations (P < 0.05) were found between measures of lying and pregnancy scan result, ewe age, sex of singleton lambs and twin birth weight for housed, Mule ewes. Only ewe age and twin birth weight were significantly associated (P < 0.05) with measures of lying for Welsh mountain ewes managed at grass. This information could help guide further research on sheep behaviour for management purposes (e.g., to optimise stocking densities and welfare for pregnant ewes). Further work should also consider evaluating measures of lying as proxies for imminent parturition.

Positive Aspects of Welfare in Sheep: Current Debates and Future Opportunities

“…Lying in a ventral posture with legs tucked under can indicate a positive state of calmness in sheep, although this behavior may vary among species, geographical locations [ 51 ], or due to parturition [ 52 ], suggesting that the reliability of this measure remains imprecise. In addition, the previous study by [ 52 ] primarily considered just welfare as a concept and not positive welfare in particular; therefore, additional study needs to consider lying behavior through a positive welfare lens.…”

Associations between Gastrointestinal Nematode Infection Burden and Lying Behaviour as Measured by Accelerometers in Periparturient Ewes

“…Ethical approval for this study was obtained from the Aberystwyth University Animal Welfare and Ethical Review Board on 18 December 2018. This study was conducted as part of a larger multi-flock study which focused on monitoring the behaviour of periparturient ewes in the final weeks of pregnancy [ 23 ]. Within this larger study, the behaviour of 98 housed Welsh Mule ewes was monitored at Aberystwyth University’s Gogerddan farm, Ceredigion, Wales.…”

“…Within this larger study, the behaviour of 98 housed Welsh Mule ewes was monitored at Aberystwyth University’s Gogerddan farm, Ceredigion, Wales. Full details regarding the larger multi-flock study have previously been reported by Williams et al [ 23 ]. However, in brief, HOBO Pendant G accelerometers (Onset Computer Corporation, Bourne, MA, USA) were fitted to the right hind leg of each ewe to record ewe lying behaviour in late pregnancy.…”

“…Data collected by the accelerometers (g-force values) for each ewe were processed using R [ 26 ] as described by Williams et al [ 23 ]. In brief, raw accelerometer data were computed to determine ewe lying behaviour, which included mean number of daily lying bouts (n/d), mean daily lying bout duration (min/bout) and mean daily lying time (min/d) using the X -axis data only.…”

Classifying the posture and activity of ewes and lambs using accelerometers and machine learning on a commercial flock

“…Despite the large body of literature on the use of accelerometers on sheep in a research setting, there is a need to better contextualise research methods with those required in a commercial setting. In a research setting, studies have trialed various objectives and methodologies with differences in sample size, deployment duration, sampling rate, window size, analysis method, sensor type, sensor position and ethogram yet few have translated their methods to a commercial system (but see Williams et al, 2021). To be feasible on a commercial scale, accelerometers need to be attached quickly with minimal handling to entire flocks, often consisting of large number of animals.…”