الفهرس 
Introduction
Effects of stress and pain on the body systemsOnly 14 pages are availabe for public view
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Abstract
We performed two studies, an experimental study aimed to investigate the effects of pre-emptive xylazine treatment and LR in combination on cardio-respiratory, endocrine-metabolic and behavioural stress responses in healthy dairy cows undergoing pain-less claw trimming on surgical tipping tables. A clinical study was performed in which we hypothesized that the sedative, analgesic and myo-relaxant effects of xylazine in a pre-emptive treatment would improve the analgesic protocol for claw treatment in LR on a surgical tipping table in lame dairy cows. Study 1 In a blinded experimental study, six healthy, non-pregnant, non-lactating, German Holstein Frisian cows were used in a cross over design with two weeks intervals between treatments. The treatments were Xyl-LR: xylazine (Rompun®, 0.05 mg kg-1 BW, IM) or Plac-LR: an equal volume of placebo 15 minutes before LR (30 minutes) for claw trimming or Xyl-St: xylazine in the same dose and route of administration without further manipulation (cows remained standing). In placebo treated cows (Plac-LR) LR induced on average a significant (P < 0.05) increase in MAP, RR, pulmonary shunt volume, plasma levels of cortisol, lactate and NEFA, a significant (P < 0.05) decrease in mean arterial partial pressure of oxygen (PaO2) and carbon dioxide (PaCO2) and arterial oxygen saturation (SaO2). Xylazine induced in average (Xyl-St) a significant (P < 0.05) reduction in HR, RR, MAP, plasma insulin, and NEFA, PaO2, SaO2, and a significant increase in plasma glucose and PaCO2. After pre-emptive sedation with xylazine (Xyl-LR) during LR HR, RR, MAP, PaO2, SaO2 and plasma levels of cortisol, lactate and NEFA, were significantly (P < 0.05) reduced whereas PaCO2 was increased compared to Plac-LR. Lowest SaO2 found during LR after xylazine treatment were about 90%. All xylazine treated cows showed mild to moderate signs of sedation, mild and clinically irrelevant free gas bloat and were able to stand and walk before and after restraining in LR. Study 2 In a prospective, blinded, placebo-controlled clinical case study, 24 lame, German Holstein Frisian cows (not more than four month pregnant). Cows were randomly allocated into two groups of 12 cows each and either treated with Xylazine (Rompun®; 0.05 mg kg-1 BW, IM) or an equal volume of sterile saline (controls) 15 minutes before LR for claw treatment. After initial claw examination in each cow a retrograde intravenous local anaesthesia (LA) with 20 ml of 2% procaine was performed. All cows treated with xylazine showed mild signs of sedation for about one to two hours, and were able to walk and to stand at all times. In the evaluation of behavioural signs xylazine demonstrated significantly additional analgesic effects to LA by reduced pain response on the insertion of the needle for LA, reduced ear flicking during claw treatment, reduced lameness score and longer standing periods in the first hour after claw treatment and improved appetite after claw treatment in LR. No significant (P < 0.05) difference was found for rumen motility in both groups. In both groups rumen motility ceased during the surgical intervention in LR. Mean HR and RR as well as plasma levels of lactate and NEFA were significantly (P < 0.05) reduced after xylazine treatment compared to baseline and controls. Mean plasma level of cortisol was significantly (P < 0.05) lower in xylazine treated cows after being turned into LR but raised to levels in controls during the surgical treatment. It was conclude that low dose xylazine treatment in healthy or clinically lame dairy cows preceding LR for painless claws trimming or surgical treatment of the claw disorders on a surgical tipping table can reduce behavioural, hormonal, and metabolic stress response. Xylazine provides additional analgesic effects to local anaesthesia in lame cows undergoing surgical claw treatment.