Cortisol concentration

4.10.4.1. Cortisol baseline

The Mean ± SD for blood cortisol has been presented in Table 8a and 8b for lateral recumbency and standing position respectively. As the results revealed, the mean baseline intravenous regional anaesthetized group was higher than mean baseline nerve block treated cows before anaesthesia with either intravenous regional or nerve block at t-39 min, t-24 min, t-12 min, t-10 min, t-5 min as well as t-1 min. However, even though there was an increased level of mean in intravenous regional anaesthetized group, there was not seen any significant difference between two treated groups.

4.10.4.2. Cortisol after treatment

The results demonstrated that mean intravenous regional anaesthetized group had a higher level compared to nerve block treated cows after anaesthesia at t+15 min, t+22 min, t+32 min, t+34 min, t+45 min, t+51 min and t+69 min. However, the mean nerve block treated group

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was greater than intravenous regional treated cows at t+2 min, t+17 min, t+27 min as well as t+39 min (t0 = anaesthesia time). Although, at those above time, mean intravenous regional anaesthetized group had a lower level compared to nerve block treated cows no significant difference was seen between two anaesthetized groups as well as their interaction with time (Group effect: P = 0.74; Group*Time effect: P = 0.55) but there was a remarkable difference regarding time (Time effect: P < 0.0001) [Fig. 103].

4.10.4.3. Cortisol concentration related to lateral recumbency

Evaluation of results using T-Test showed, the mean plasma cortisol concentration in intravenous regional anaesthetized cows was more than nerve block treated group before and after lateral recumbency at t-20 min, t-5 min and t+7 min. However, there was not seen any significant difference between two groups at those time before and after turning cows to lateral recumbency at t-20 min and t+7 min (P T-20, T+7 > 0.05; t0 = LR time). On the other hand, the significant difference between two treated groups was seen at t-5 min (P _T-5 = 0.03;

t0 = LR time) which is irrelevant to anaesthesia effect [Fig. 104]. Further, application of proc GLM revealed, Group effect: P = 0.19, Time effect: P < 0.0001 and Group*Time effect: P = 0.73.

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4.10.4.4. Cortisol concentration related to turning to standing position

According to evaluated T-Test results, the mean plasma cortisol concentration in nerve block treated cows was more than intravenous regional anaesthetized group at t-1 min while the mean cortisol concentration in intravenous regional treated group was greater compared to nerve block treated cows at t+5 min with no significant difference between two treated groups at both time (P T-1, T+5 > 0.05; t0 = returning cows to standing position from lateral recumbency time) [Fig. 105]. Additionally, application of proc GLM revealed, Group effect:

P = 0.22, Time effect: P 0.47 and Group*Time effect: P = 0.43.

4.10.4.5. Cortisol concentration related to first (control), second and third nociceptive thresholds

The evaluated T-Test resulted revealed that, the mean plasma cortisol concentration in both groups had an increase level before and after first nociceptive threshold measurement at t-1 min, t+1 min and t+5 min. The mean cortisol concentration in intravenous regional treated cows was more than nerve block treated group at those mentioned time before anaesthesia application although there was not seen any significant group difference between two treated groups with either nerve block or intravenous regional method before and after first

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nociceptive threshold measurements (P T-1, T+1, T+5 > 0.05; t0 = first nociceptive threshold measurement). Application of proc GLM showed, Group effect: P = 0.41, Time effect: P = 0.03 and Time*Group effect: P = 0.77. Regarding second nociceptive threshold assessment, the mean plasma cortisol concentration in intravenous regional treated cows was greater than nerve block anaesthetized cows at t-1 min and t+5 min while the mean cortisol concentration in intravenous regional treated cows showed a lower level compared to nerve block anaesthetized group at t+1 min without any significant group difference between two different groups at those time before as well as after second nociceptive threshold measurement (P T-1,

T+1, T+5 > 0.05; t0 = second nociceptive threshold measurement). Further, proc GLM showed,

Group effect: P = 0.95, Time effect: P = 0.058 and Group*Time effect: P = 0.53. Assessment of measured cortisol concentration before and after third nociceptive threshold measurement revealed, the mean plasma cortisol concentration in intravenous regional treated cows had a higher level compared to nerve block treated cows at t-1 min and t+1 min while had a lower level than nerve block treated cows at t+5 min (t0 = third nociceptive threshold measurement). However, any remarkable group difference between two different anaesthetized groups was not seen at those time point (P T-1, T+1, T+5 > 0.05; t0 = third nociceptive threshold measurement) [Fig. 106]. Moreover, evaluated results by proc GLM showed, Group effect: P = 0.90, Time effect: P = 0.007 and Time*Group effect: P = 0.31.

0

Fig. 106: Mean cortisol concentration before and after anaesthesia application with either nerve block or intravenous regional anaesthesia before and following each pain stimulations. Error bars represent standard deviation.

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4.10.4.6. Cortisol concentration related to anaesthesia

According to assessed result using SAS program for repeated measurements, the mean plasma cortisol concentration in intravenous regional treated cows was higher than nerve block treated group before anaesthesia application at t-1 min while mean cortisol concentration in nerve block treated cows was greater than intravenous regional group at t+2 min (t0 = anaesthesia time). However, any significant difference between two groups was not seen regarding type of anaesthesia method at those time (P T-1, T+2 > 0.05; t0 = anaesthesia time) [Fig. 107]. Besides, proc GLM revealed, Group effect: P = 0.88, Time effect: P = 0.05 and Time*Group effect: P = 0.08.

4.10.4.7. Cortisol concentration related to inflation of tourniquet

According to evaluated results, the mean plasma cortisol concentration in intravenous regional treated cows was higher than nerve block anaesthetized cows before and after tourniquet application at t-1 min and t+3 min. However, any significant difference between two treated groups was not seen related to type of anaesthesia at those time (P T-1, T+3 > 0.05;

t0 = tourniquet inflation time) [Fig. 108]. Application of proc GLM for further assessment revealed, Group effect: P = 0.59, Time effect: P = 0.03 and Time*Group effect: P = 0.94.

0

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4.10.4.8. Cortisol concentration related to deflation of tourniquet

As the results revealed, the mean plasma cortisol concentration in intravenous regional treated cows was higher than nerve block treated group at t-1 min, t+5 min and t+23 min without any significant difference regarding type of anaesthesia method at those time before and after tourniquet release (P T-1, T+5, T+23 > 0.05; t0 = tourniquet deflation time) [Fig. 109].

Furthermore, proc GLM showed, Group effect: P = 0.86, Time effect: P = 0.0002 and Time*Group effect: P = 0.87.

4.11. Effect of application of tourniquet in hind limb intravenous regional anaesthesia