Ovine locomotion studies are rare, despite their relevance for medical research. The aim of this preliminary study was to investigate habituation and temporospatial parameters during treadmill walking of seven Austrian Mountain sheep. Sheep were naïve to treadmill exercise. During five treadmill sessions, movement cycle duration (MCD), vertical trunk movement (VTM), stride height (SH), stride length (SL), and percentage of movement cycle at stance (%St) were assessed. Two sheep were excluded from the study because they would not walk on the treadmill. From the end measurement session, MCD (0.95 s) and %St (62%) were similar to reported kinetics of sheep walking over ground, although stride length (1.05 m) was longer in this study. These findings suggest that sheep may require more than five sessions to become habituated to treadmill walking. KeywordsSheep; Locomotion; Kinematics; Habituation; Treadmill Live sheep are commonly used as an animal model for orthopaedic research. Due to the similarities between ovine and human skeletons, sheep are often used in studies of the human spine (Reitmaier et al., 2013) and knee joints (Tapper et al., 2006(Tapper et al., , 2008. Extrapolation from sheep models to humans can only be meaningful if biomechanical interspecies variations are well documented. As a part of a larger comparative biomechanical human and sheep study, this study examined some key aspects of ovine locomotion. While the kinetics of sheep locomotion over ground have been reported (Kim and Breur, 2008;Agostinho et al., 2012), adequate descriptions of temporospatial locomotion parameters in healthy sheep using a kinematic set-up and treadmill are lacking, as are the number of training sessions required for treadmill habituation. Therefore, the aim of this study was to report kinematic parameters in mature sheep during treadmill walking, and to identify habituation to treadmill walk over five treadmill sessions. Conflict of interest statementNone of the authors of this paper has a financial or personal relationship with other people or organisations that could inappropriately influence or bias the content of the paper. Seven mature Austrian Mountain sheep (2.1 ± 0.88 years; 72.2 ± 7.29 kg) were included. All sheep were accustomed to walking and trotting in-hand over the non-moving treadmill (Mustang 2200, Kagra). Ethical approval was granted from the Austrian Federal Ministry of Science and Research (13/10/97/2011). Europe PMC Funders GroupAll of the sheep were deemed to be sound by an experienced orthopaedic veterinarian. Reflective markers were attached to the head, withers, sacrum, and below each fetlock joint. Ten high speed cameras (Eagle Digital Real Time System; 1200 Hz) were used for kinematic data collection using kinematic software (Cortex 3.6, Motion Analysis). Data were collected during four treadmill training sessions (A-D) and an end session (E), against which all measurements were compared. Training days were interspersed by over ground exercise only or rest (Table 1). Sessions A-D con...

SummaryBackgroundMuscle fatty infiltration (MFI) has been identified in patients with spinal pain using magnetic resonance imaging (MRI). Even though sheep are a commonly used animal model for the human spine, comparative sheep MFI data from MRI is not available. Determining MFI in sheep spinal muscles using acquisition protocols commonly used in man will identify the applicability of this approach in future sheep model studies, such that the effects of spinal interventions on muscle can be assessed prior to their use in a human (clinical) population.ObjectiveTo quantify ovine lumbar spine MFI using three-dimensional two-point Dixon and T1-weighted sequences.MethodsT1-weighted and Dixon lumbar spine axial sequences were collected in 14 healthy Austrian mountain sheep using a 1.5-T MRI. At each vertebrae, the region of interest of psoas major and minor (PS), multifidus (M), and longissimus (L) were identified. To determine MFI from the T1-weighted images, the mean pixel intensity (MPI) was calculated as a percentage of subcutaneous or intermuscular fat. For the Dixon images, fat sequence MPI was calculated as a percentage of the summed fat and water sequence MPIs. Spinal degeneration was graded and correlated to MFI. Dixon MFI was compared to T1-weighted MFI obtained from subcutaneous and intermuscular fat.ResultsFor every muscle, T1-weighted MFI calculated using subcutaneous fat scored significantly lower than Dixon MFI and T1-weighted MFI calculated using intermuscular fat (p < 0.001). There were no significant MFI differences between T1-weighted images calculated using intermuscular fat and Dixon images for M and L (p > 0.05), although significant differences were found for PS.ConclusionIn sheep, Dixon sequences provide an acceptable comparison to T1-weighted sequences for lumbar extensor MFI based on intermuscular fat. However, compared to the human literature, ovine lumbar musculature contains greater MFI, making interspecies comparisons more complex.