BACKGROUND

Pre-operative fasting is considered a deviation from normal husbandry conditions and always requires a permission within the animal experimental license. Current pre-operative fasting recommendation in sheep however are rather vague and not evidence-based. A standardized approach to pre-operative fasting and water restriction is desirable because the different physiologic effects of varying restriction periods may introduce ‘noise’ into physiologic data and consequently hamper reproducibility of study results. This study will elaborate the benefits and disadvantages of food with or without water withdraw in sheep. By assessing both, physiological properties and animal welfare (stress), a harm-benefit analysis will allow for an improved evidence based recommendation on the issue. Furthermore, if pre-operative fasting shows to be beneficial for a significant reduction of rumen filling, the fasting procedure could possibly be refined by leaving the sheep within the group and preventing food intake by muzzeling the sheep.