Antagonistic effects of intravenous or epidural atipamezole on xylazine-induced dorsolumbar epidural analgesia in cattle

Effect of a single epidural administration of follicle-stimulating hormone via caudal vertebrae on superstimulation for in vivo and in vitro embryo production in Japanese black cows

Here, we describe a simplified procedure for embryo production in the Japanese black cow that uses a single caudal epidural injection of follicle-stimulating hormone (FSH). First, we compared the efficiency of superovulation for in vivo embryo production between conventional multiple FSH treatment (control, n = 10) and single epidural administration (epidural, n = 5). The number of transferable blastocysts was similar between control and epidural groups (4.7 ± 3.5 and 9.0 ± 6.0, respectively). Next, we compared in vitro embryo production by ovum pick-up and in vitro fertilization (OPU-IVF) between control (n = 12) and epidural groups (n = 12). The rate of development to transferable blastocysts was higher in the epidural group than in the control (23.3 vs. 10.5%, P < 0.001). In conclusion, a single epidural administration of FSH can induce follicular development comparable to that of the conventional superovulation protocol and may improve the productivity of OPU-IVF.

Technological, environmental and biological factors: referent variance values for infrared imaging of the bovine

Background

Despite its variety of potential applications, the wide implementation of infrared technology in cattle production faces technical, environmental and biological challenges similar to other indicators of metabolic state. Nine trials, divided into three classes (technological, environmental and biological factors) were conducted to illustrate the influence of these factors on body surface temperature assessed through infrared imaging.

Results

Evaluation of technological factors indicated the following: measurements of body temperatures were strongly repeatable when taken within 10 s; appropriateness of differing infrared camera technologies was influenced by distance to the target; and results were consistent when analysis of thermographs was compared between judges. Evaluation of environmental factors illustrated that wind and debris caused decreases in body surface temperatures without affecting metabolic rate; additionally, body surface temperature increased due to sunlight but returned to baseline values within minutes of shade exposure. Examination/investigation/exploration of animal factors demonstrated that exercise caused an increase in body surface temperature and metabolic rate. Administration of sedative and anti-sedative caused changes on body surface temperature and metabolic rate, and during late pregnancy a foetal thermal imprint was visible through abdominal infrared imaging.

Conclusion

The above factors should be considered in order to standardize operational procedures for taking thermographs, thereby optimizing the use of such technology in cattle operations.

Serum clearance of iodixanol for estimating glomerular filtration rate in calves

To evaluate serum clearance of iodixanol, applicable to the estimation of glomerular filtration rate (GFR), clinically healthy and experimentally-induced nephropathy calves were prepared. Iodixanol was administered intravenously at 40 mg I/kg, and blood was withdrawn 60, 120, and 180 min later. Serum iodixanol concentration was determined by high-performance liquid chromatography. No statistical difference in GFR was noted between strains (Holstein vs. Japanese Black) or sexes, and the α(2)-adrenergic agonist xylazine increased GFR. In calves subjected to right renal vessel ligation, followed by a left nephrectomy, a marked reduction in GFR was observed with renal ischemic changes. These results suggest that the GFR estimation by serum iodixanol clearance is a ready-to-use tool in calf research and practice owing to the ease of monitoring serial renal function.

Alpha2-adrenergic impact on hypothalamic magnocellular oxytocinergic neurons in long evans and brattleboro rats: effects of agonist and antagonists

We have previously demonstrated that alpha2-adrenoceptors regulate hypothalamic magnocellular oxytocinergic (OXY) neurons in Sprague Dawley rats. Here we investigated whether activation/inhibition of alpha2-adrenoceptors may similarly trigger/downregulate the activity of OXY neurons in control Long Evans (+/+) and permanently osmotically stressed Brattleboro (di/di) rats. The effect of alpha2-adrenoceptor agonist, xylazine (XYL) and alpha2-adrenoceptor antagonists, atipamezole (ATIP), and idazoxan (IDX) were evaluated in the supraoptic (SON) and paraventricular (PVN) hypothalamic nuclei. Saline (SAL, 0.1 ml/100 g), XYL (10 mg/kg), ATIP, (1 mg/kg), and IDX (10 mg/kg) and IDX or ATIP followed by XYL were applied intraperitoneally. Rats were sacrificed 90 min later and Fos/OXY co-labelings analyzed in microscope. In control +/+ rats no or few Fos/OXY co-labelings occurred in SON and PVN. XYL significantly increased Fos incidence in OXY neurons in both nuclei. ATIP significantly suppressed the effect of XYL in both nuclei and IDX only in SON. In di/di controls 81% of OXY neurons in SON and 44% in PVN revealed Fos presence and XYL did not further elevate Fos number in SON OXY neurons and slightly increased Fos number in PVN. ATIP or IDX only partially reduced Fos in SAL or XYL treated di/di rats. Our data indicate that: (1) XYL stimulation is not effective in di/di rats because of sustained upregulation of OXY neurons activity and (2) neither ATIP nor IDX reduced significantly the OXY activity in control di/di rats. These findings suggest that alpha2-adrenoceptors have only a limited impact in maintaining OXY cells activity upregulation in PVN and SON of di/di rats.

High Caudal Epidural Anaesthesia with Local Anaesthetics or ?2-Agonists in Calves

The objective of this study was to examine the efficacy of a caudal epidural anaesthesia using lidocaine or xylazine in a high volume for analgesia of the flank, navel and hamstring tendon. Fourteen calves weighing 57.7 +/- 5.1 kg and 37.9 +/- 9.3 (mean +/- SEM) days old were randomly divided into two groups of seven calves each. Calves belonging to the lidocaine group were given a 2% lidocaine solution in the sacrococcygeal vertebral space epidurally at a volume of 0.4 ml/kg (8 mg/kg) body weight (BW). Animals of the xylazine group were administered an epidural anaesthesia with xylazine at a dose of 0.1 mg/kg BW, diluted with a 0.9% saline solution to a corresponding final volume of 0.4 ml/kg BW. Heart rate and respiratory rate were measured and the degree and duration of analgesia was determined by the response to a skin prick with a hypodermic needle over a period of 350 min after epidural injection. After epidural anaesthesia with lidocaine the mean heart rate increased during dorsal recumbency, whereas after xylazine both heart rate and respiratory rate decreased significantly (P < 0.05). The epidural injection of xylazine compared with lidocaine caused longer (P < 0.05) analgesia at the hamstring tendon (mean +/- SEM, 120.7 +/- 29.7 min versus 93.6 +/- 3.5 min) and at the flank (100.7 +/- 24.4 min versus 78.3 +/- 11.1 min). There were no differences in the intensity of analgesia between groups. After xylazine application analgesia at the navel was achieved for 95.0 +/- 14.1 min whereas after lidocaine injection sufficient analgesia at the navel was found in just two of seven calves for 55 and 95 min respectively. Based on above experiences, a second study was performed, in which a combination of xylazine and local anaesthetics was used and the injection volume was increased to prove the efficacy of caudal epidural anaesthesia in 15 calves (26.3 +/- 26.7 days; 57.1 +/- 19.5 kg) submitted to the clinic for regular umbilical surgery. In these cases the xylazine (0.1 mg/kg BW) was diluted with 2% lidocaine (n = 7) or 2% procaine (n = 8) to a corresponding final volume of 0.5-0.6 ml/kg BW. In all cases complete anaesthesia of the surgical area was achieved and no adverse effects were observed. Overall the high volume caudal epidural anaesthesia represents an effective, safe, cheap and easy to perform alternative for anaesthesia of the navel, flank and hamstring tendon in calves without major side effects.

Epidural administration of fixed volumes of xylazine and lidocaine for anesthesia of dairy cattle undergoing flank surgery

A modified method for epidural anesthesia in standing cattle undergoing flank surgery in which fixed volumes of xylazine and lidocaine were injected is described, along with results in 18 cattle. A Tuohy needle was inserted into the L1-2 intervertebral space from a dorsal midline approach, positioning of the needle tip in the epidural space was confirmed by use of the hanging drop technique, the needle was slowly advanced 7 to 10 mm to penetrate the epidural fat, and the anesthetic solution was then administered. In the initial 8 cattle, the anesthetic solution consisted of 1 mL of 2% xylazine and 4 mL of 2% lidocaine. However, 1 of these cattle became recumbent prior to surgery. Therefore, the dose of lidocaine was decreased, and in the subsequent 10 cattle, the anesthetic solution consisted of 1 mL of 2% xylazine and 3 mL of 2% lidocaine. Surgery was begun 30 minutes after epidural administration of anesthetic; surgery time ranged from 27 to 276 minutes. Sedation and anesthesia were adequate, except in 1 cow that received the lower dose of lidocaine and became recumbent during suturing of the incision. The modified epidural anesthesia technique with injection of fixed volumes of xylazine and lidocaine appears to be an adequate method for anesthesia of standing cattle undergoing flank surgery.

Clinical assessment of epidural analgesia induced by xylazine-lidocaine combination accompanied by xylazine sedation in calves

The aim of the present study was to investigate whether epidural administration of a xylazine-lidocaine combination accompanied by xylazine sedation would provide satisfactory analgesia for some surgical procedures on 10 calves admitted to the Department of Veterinary Surgery, University of Kafkas with perineal urolithiasis (n:2), rectovaginal fistula (n:1), atresia ani (n:2), omphalophlebitis (n:2), omphaloarteritis (n:1) and umbilical hernia (n:2).

Following intramuscular injection of xylazine at a dose of 0.05 mg/kg for sedation, xylazine-lidocaine combination (0.2 mg/kg lidocaine + 0.02 mg/kg xylazine + 5 ml 0.9% NaCl) was administrated into the lumbosacral (L₆-S₁), sacrococcygeal (S₅-Co₁) or intercoccygeal (Co₁-Co₂) space. Heart rate, respiratory rate and rectal temperature were recorded prior to and during analgesia at 5, 10, 15, 30 and 60 minutes. Furthermore, depth and duration of analgesia were evaluated during surgical intervention.

The study revealed that the combination of epidural xylazine-lidocaine with xylazine sedation was highly satisfactory for surgery of the lower urinary tract and the perineal region, but it was less so for surgery of the umbilical area.

Distribution of new methylene blue injected into the caudal epidural space in cattle

To investigate the distribution of solutions injected into the first intercoccygeal epidural space, 24 adult, standing cattle were randomly assigned to 5-, 10- and 20-mL groups and injected with 0.12% new methylene blue (NMB) in 0.9% saline. Ten heifers received 1 mL NMB solution/100 kg of body weight. There was a significant correlation between the injected volume and the number of cranially stained spinal segments in three adult cattle groups (correlation coefficient R2=0.46; P<0.0001). In three cattle, NMB solution did not distribute more than one spinal segment cranially from the injection site due either to fibrosis of the epidural tissue or to inadvertent intravenous administration into the epidural vein. The study showed that the larger the volume of solution injected, the greater the spread with increased individual variation. The results could form the basis for determining the volume of injection required and for evaluating the pharmacokinetics of anaesthetics used in caudal epidural anaesthesia.

Efeitos da administração epidural de amitraz, xilazina ou dimetil sulfóxido em vacas

Avaliaram-se os efeitos da injeção epidural de amitraz (0,4mg/kg), xilazina (0,05mg/kg) ou dimetil sulfóxido 10% (5,0ml) sobre a freqüência cardíaca (FC), pressão arterial sistólica (PAS), freqüência respiratória (FR), motilidade ruminal (MR), temperatura retal (TR), altura de cabeça (AC) e latência das respostas a estímulos nociceptivos nas regiões da coxa (LECC) e coroa do casco (LRRM) de vacas. Houve diminuição da FC e da MR nos grupos xilazina e amitraz. O tratamento com xilazina resultou em alterações na FR, PAS e AC. LECC e LRRM foram maiores nos tratamentos com agonistas alfa-2. Nas doses utilizadas, o amitraz aumentou a latência de resposta a estímulo nociceptivo em menor grau que a xilazina, sem induzir efeitos colaterais sistêmicos severos, em vacas.