Rechallenge of previously-infected pregnant ewes with Chlamydophila abortus

We studied some behavioural, clinical, biochemical and haematological variables in Desert (Najdi) sheep and goats subjected to the acute stressful stimulus of isolation from the flock, and the influence of pretreatment with xylazine (n = 6) or sodium betaine (n = 6). The isolation stress resulted in increased vocalization and in variable and statistically nonsignificant increases in heart, pulse and respiratory rates. Isolation caused significant increases in the plasma concentrations of cortisol (from about 35.2 to about 83.8 mmol/L) and glucose (from 3.1 to 4.2 mmol/L), and a decrease in that of magnesium (from 0.82 to 0.65 mmol/L). The endogenous thiocyanate concentration was unaffected. The isolation stress also significantly decreased the haematocrit (PCV), and the number of lymphocytes, and increased the concentration of haemoglobin. Pretreatment of sheep and goats with xylazine at a dose of 0.01 mg/kg by the intravenous route significantly ameliorated the effects induced by the stressful stimulus. The effects of pretreatment of the two species with sodium betaine (10 mg/kg) produced variable and nonsignificant effects. There were no significant differences between sheep and goats in the responses to the isolation stress, except in vocalization, which was greater in sheep than in goats.     

Stress associated with road transportation in desert sheep and goats, and the effect of pretreatment with xylazine or sodium betaine

The present work investigates some clinical, endocrinological, biochemical and haematological variables in desert sheep and goats stressed in the course of individual road transportation, and the influence thereon of pretreatment with an established anti-stressor drug, xylazine HCl, and a test compound, sodium betaine (trimethylglycine). Road transportation for 2h resulted in variable and statistically insignificant increases in heart, pulse and respiratory rates in both control and experimental animals. Transportation stress significantly increased the concentrations of plasma cortisol, and glucose, and decreased that of magnesium. The endogenous thiocyanate concentration was unaffected. The stress also insignificantly decreased the haematocrit (PCV), and the number of lymphocytes, and increased the concentration of haemoglobin. Pretreatment of sheep and goats with xylazine at a single dose of 0.01 mg/kg by the intravenous route significantly ameliorated the effects induced by the stressful stimulus. The effects of pretreatment of the two species with sodium betaine (10 mg/kg) produced variable and insignificant effects.     

Tyrosine Ameliorates Some of the Clinical,Biochemical and Haematological Effects of Acute Stress Associated with Transportation of Desert Sheep

We studied some clinical, biochemical and haematological variables in Desert (Najdi) sheep acutely stressed in the course of individual road transportation, and the influence thereon of pretreatment with tyrosine. Transportation for 30 min resulted in variable but statistically insignificant increases in heart, pulse and respiratory rates. It also caused significant increases in the plasma concentration of cortisol (from 43.5 to 101.7 mmol/L) and glucose (from 3.1 to 4.5 mmol/L), and a decrease in that of magnesium (from 0.85 to 0.72 mmol/L). The endogenous thiocyanate level was unaffected. The transportation stress also decreased the haematocrit (PCV) and the number of lymphocytes, and increased the concentration of haemoglobin. Pretreatment of sheep with tyrosine at a dose of 100 mg/kg by the intravenous route significantly ameliorated the stress-induced clinical, biochemical and haematological changes. The treatment caused no overt adverse effects.     

The effect of magnesium aspartate, xylazine and morphine on the immobilization-induced increase in the levels of prolactin in turkey plasma

The effect of pre-treating turkey poults (8 weeks old) with magnesium aspartate, xylazine or morphine on the concentration of prolactin (PRL) in plasma was studied in normal birds, and birds stressed with immobilization. Acute immobilization (2 h) without drug treatment increased significantly the PRL concentration in plasma. Pretreatment with magnesium aspartate (405 mg/ml) at intramuscular doses of 100, 200, and 400 mg/bird decreased significantly, in a dose-dependent manner, the PRL plasma concentration when compared with the immobilized birds. Drug treatment without immobilization had no significant effect on PRL concentration. Similar results were obtained with xylazine (20 mg/ml) when given to birds intramuscularly at doses of 5, 10, or 20 mg/bird, 1 h before immobilization. Morphine, at intramuscular doses of 5 or 10 mg/kg, did not affect significantly the prolactin concentration of immobilized turkeys. At a dose of 25 mg/kg, however, it significantly lowered the PRL plasma concentration in immobilized birds. Morphine treatment alone did not influence significantly the basal PRL plasma concentration.     

Comparative pharmacokinetics of amoxicillin/clavulanic acid combination after intravenous administration to sheep and goats

The pharmacokinetic behaviour of an amoxicillin/clavulanic acid combination was studied after intravenous administration of single doses (20 mg/kg per kg body weight) to five sheep and six goats. The objective was to determine whether there are differences between sheep and goats in the disposition of amoxicillin and clavulanic acid. The plasma concentration-time data were analysed by compartmental pharmacokinetic and non-compartmental methods. The disposition curves for both drugs were best described by a biexponential equation (two-compartment open model) in sheep and goats. The elimination half-lives of amoxicillin were 1.43 ± 0.16 h in sheep and 1.13 ± 0.19 h in goats, and of clavulanic acid were 1.16 ± 0.01 h and 0.85 ± 0.09 h in sheep and goats respectively. The apparent volumes of distribution of amoxicillin and clavulanic acid were similar in the two species. Body clearances of amoxicillin were 0.09 ± 0.01 L/h kg in sheep and 0.11 ± 0.01 L/h kg in goats, and of clavulanic acid were 0.07 ± 0.01 L/h kg and 0.12 ± 0.01 L/h kg in sheep and goats respectively. The half-lives and body clearances of amoxicillin and clavulanic acid differed significantly between sheep and goats. It was concluded that the disposition of amoxicillin and clavulanic acid administered intravenously as an amoxicillin/clavulanic acid combination to sheep and goats differed between the two ruminant species. Even though the differences in disposition kinetics of both drugs were statistically significant, the same intravenous dosing rate of this antimicrobial combination can generally be used in sheep and goats.     

Pharmacokinetics of danofloxacin 18% in lactating sheep and goats

The pharmacokinetics of danofloxacin administered at 6 mg/kg bodyweight by the intravenous and subcutaneous (s.c.) routes were determined in sheep and goats. Milk concentrations were also determined following s.c. administration. Plasma and milk concentrations of danofloxacin were measured using high-performance liquid chromatography. The plasma concentration-time curves were analysed by noncompartmental methods. Danofloxacin had a similar large volume of distribution at steady state in sheep and goats of 2.19 +/- 0.28 and 2.43 +/- 0.13 L/kg, and a similar body clearance of 0.79 +/- 0.15 and 0.98 +/- 0.13 L/kg.h, respectively. Following s.c. administration, danofloxacin achieved a similar maximum concentration in sheep and goats of 1.48 +/- 1.54 and 1.05 +/- 0.09 mg/L, respectively at 1.6 h and had a mean residence time of 4.93 +/- 0.79 and 4.51 +/- 0.44 h, respectively. Danofloxacin had an absolute bioavailability of 93.6 +/- 13.7% in sheep and 97.0 +/- 15.7% in goats and a mean absorption time of 2.07 +/- 0.75 and 2.01 +/- 0.53 h, respectively. Mean danofloxacin concentrations in milk after s.c. administration to sheep were approximately 10 times higher than plasma at 12 h postdose and remained eight times higher at 24 h postdose. In goats, mean concentration of danofloxacin in milk were approximately 13 times higher than plasma at 12 h postdose and remained four times higher at 24 h postdose. Thus, danofloxacin 18% administered s.c. to lactating ewes and goats at a dose rate of 6 mg/kg was characterized by extensive absorption, high systemic availability and high distribution into the udder resulting in higher drug concentrations being achieved in milk than in plasma.     

Comparison of xylazine and lidocaine effects for analgesia and cardiopulmonary functions following lumbosacral epidural injection in goats

The present study was carried out in order to compare the effects of xylazine and lidocaine on analgesia and cardiopulmonary parameters following epidural injection in goats. Twelve healthy Small East African goats of both sexes (mean +/- SD; 15.6 +/- 1.9 kg body weight) were used. The goats were randomly assigned to two groups of five and seven animals. The first group (n = 5) was given 2% lidocaine-HCl at 4400 micrograms/kg body weight. The second group (n = 7) was administered 2% xylazine-HCl at 150 micrograms/kg body weight. All drugs were diluted in 5 ml of sterile water and were injected epidurally through the lumbosacral interspace with the injection taking over 20 s. Both drugs induced analgesia within 5 min. Signs of sedation, cardiopulmonary changes and lateral recumbency developed within 5-7 min after administration of epidural xylazine. Tail flaccidity and hind limb paralysis developed 3 min after epidural administration of lidocaine. The time from recumbency to regaining normal stance was 60 and 158 min for xylazine- and lidocaine-treated animals respectively. Xylazine induced adequate analgesia of the flank and perineum, which extended to the head and forelimbs. In contrast, lidocaine induced adequate bilateral flank and perineal analgesia extending up to the third thoracic vertebra. For both drugs, analgesia of the flank and perineum persisted for the entire 180-min observational period. Epidural injection of xylazine and lidocaine caused variable depression effects on the cardiopulmonary values but was not so low as to cause concern. It is concluded that lumbosacral epidural injection of xylazine at 150 micrograms/kg body weight in 5 ml of water for injection offers the most desirable sedation and analgesia of the flank and perineum. The longer duration of analgesia may be useful for postoperative analgesia and relief of continuous straining in goats.     

Comparative pharmacokinetics of amoxicillin administered intravenously to sheep and goats

The pharmacokinetic behavior of sodium amoxicillin was studied after intravenous administration to six sheep and five goats to determine if there are species differences in disposition. The plasma drug concentrations vs. time following intravenous administration of 10 mg/kg were best described by the biexponential equations Cp = 42.9e-0.077.t + 3.68e-0.0134.t for goats, and Cp = 53.5e-0.06.t + 1.69e-0.015.t for sheep. The terminal disposition half-lives for sheep and goats were 46.3 and 66.9 min respectively and were not significantly different. Amoxicillin clearance for sheep and goats were 10.1 and 11.4 ml/min.kg respectively. There were no significant differences between any of the pharmacokinetic parameters measured in sheep and goats.     

Probable post-synaptic α2 adrenergic mediated effect of xylazine on goat uterine motility*

Perez, R., Cox, J.F., Arrue, R. Probable post-synaptic ot2 adrenergic mediated effect of xylazine on goat uterine motility. J. vet. Pharmacol. Therap. 17 , 59–63. Xylazine has been characterized as a selective α₂-adrenoceptor agonist, which has explained its central nervous system depressant and other pharmacological effects. In order to characterize the effect of xylazine on uterine motility during the oestrus cycle in goats intrauterine pressure changes were recorded in cycling goats using balloon-tipped catheters placed in the uterine horns and connected to pressure transducers and a recorder. The effect of xylazine on myometrial activity was studied by giving increasing doses of the drug (1.0, 10.0, 100.0 or 500.0 m̈g/kg) intravenously (i.v.) to animals either in the follicular or the luteal phase of the cycle. To establish the subtype of a adrenergic receptor mediating the action of xylazine, goats were pretreated with either prazosin (1.0 mg/kg, i.v.) or yohimbine (1.0 m̈g/kg, i.v.). To establish whether the effect of xylazine was pre- or post-synaptic, xylazine (100 mg/kg, i.v.) was administered to goats pretreated with reserpine (0.8 mg/kg, i.p.) to deplete presynaptic catecholamine stores. Xylazine induced a significant and dose-dependent increase on uterine motility in cycling goats, apparently mediated by postsynaptic oc₂-adrenoceptors.     

The reversal of xylazine hydrochloride by yohimbine and 4-aminopyridine in goats

Yohimbine, 4-aminopyridine, and a combination of the 2 drugs were studied to assess their potential as antagonists to xylazine in goats. Twenty-four small East African goats were divided randomly into 4 groups of 6 goats each in a placebo-controlled study. They were all treated with intramuscular xylazine at 0.44 mg/kg. At the time of maximum sedation, sterile water was administered intravenously to the control group, 0.15% 4-aminopyridine at 0.4mg/kg to Group 2, 0.1% yohimbine at 0.25 mg/kg to Group 3, and the combination of the 2 drugs at the same dose rates to Group 4. The yohimbine/4-aminopyridine combination was also used to antagonise xylazine at 0.88mg/kg in 6 goats. The heart rate, respiratory rate and rate of ruminal movements, the pedal and palpebral reflexes as well as the reaction to noxious stimuli, the standing time and the total recovery time were established and evaluated to assess the effects of the treatments. The drugs reversed the xylazine-induced decrease in the heart rate, respiratory rate and rate of ruminal movements, and also rapidly restored the reflexes as well as the reaction to noxious stimulation. In addition, they significantly (P < 0.05) decreased the mean standing time. The mean total recovery time was decreased significantly (P < 0.05) by 4-aminopyridine and the yohimbine/4-aminopyridine combination, but non-significantly (P > 0.05) by yohimbine. No relapse in sedation occurred. Overall, the combination of yohimbine and 4-aminopyridine produced better responses than the individual drugs, and may therefore be used for rapid reversal of xylazine-induced sedation in goats. Yohimbine or 4-aminopyridine may also be useful for this purpose but recovery may be prolonged.     

Analgesic and systemic effects of xylazine, lidocaine and their combination after subarachnoid administration in goats

The objective of the study was to determine the analgesic and systemic effects of subarachnoid administration of xylazine hydrochloride (XY), lidocaine hydrochloride (LI) and their combination (XYLI) in goats. Six healthy goats were used in a prospective randomised study. Three treatments were administered to each goat, with 1-week intervals between each treatment. Treatments consisted of 0.1 mg/kg xylazine, 2.5 mg/kg lidocaine and a combination of xylazine 0.05 (mg/kg) and lidocaine (1.25 mg/kg). Analgesia, ataxic, sedative, cardiovascular and respiratory effects, and rectal temperature were evaluated before (baseline) and at 5, 10, 15, and 30 min after subarachnoid injection, and then at 30-min intervals until loss of analgesia occurred. Lidocaine induced analgesia in 3.1 +/- 1 min (mean +/- SD), which lasted for 66 +/- 31 min. Heart and respiratory rates and blood pressure remained unchanged after lidocaine-induced analgesia. Xylazine induced analgesia in 9.5 +/- 2.6 min and xylazine-lidocaine in 3.2 +/- 1.2 min. Xylazine-lidocaine-induced analgesia lasted longer (178.3 +/- 37 min) than that induced by xylazine (88.3 +/- 15 min). The XYLI treatment induced prolonged motor blocking (115 min), more than the XY (80 min) and LI (90 min) treatments. Both xylazine and xylazine-lidocaine caused significant decreases in the heart and respiratory rates, but not in blood pressure. The combination of xylazine (0.05 mg/kg) and lidocaine (1.25 mg/kg) can be administered subarachnoidally (between last lumbar vertebra and 1st sacral vertebra) to produce prolonged (> 2.5 h) analgesia of the tail, perineum, hind limbs, flanks and caudodorsal rib areas in goats. Despite the prolonged analgesia, using this combination is desirable for relieving postoperative pain, but it may be a disadvantage due to a motor block when dealing with goats.     

热应激状态下羊的体温调节

热应激是由高温环境所引起的,在炎热的气候条件下,当环境有效温度超过羊的等热区上限温度时,羊就会出现热应激。由热应激引发的不良影响广泛存在,不仅严重影响羊的生存质量,而且导致羊体温升高、生长性能降低、免疫力减弱以及肉品质下降。本文综述了导致羊产生热应激的因素以及热应激条件下的体温调节机制。在热应激的情况下,机体通过吸收环境辐射热和累积机体代谢产热,使机体获得很高的热负荷,超过了机体的散热能力。暴露在高温环境中的羊只,可通过增加机体散热消除过多的热负荷。当空气温湿度发生变化时,作为恒温动物,绵羊和山羊可以通过调整自身的产热量、采食量、饮水量、呼吸频率和行为等方式,来维持机体产热和散热的平衡。总之,羊可以利用复杂有效的散热机制维持体温平衡,适应高温环境。     

The Stress Responses Involved in General Anaesthesia in Cattle

Anaesthesia was induced in four adult Friesian cows with intravenous thiopentone (10 mg/kg) after either intramuscular saline (2ml), acepromazine (0.05mg/kg) or xylazine pre- medication (0.05 mg/kg). At least 4 weeks was allowed to alapse between each anaesthetic in each cow. The stress involved in induction of and recovery from anaesthesia was assessed by measuring pulse and respiration rates, plasma cortisol and glucose concentrations, total plasma protein concentration and haematocrit at 10–15 minute intervals from 60 min prior to premedication to the time when the animals stood after anaesthesia. Recovery from anaesthesia was associated with an increase in cortisol concentration. This response was significantly attenuated by premedication with xylazine but not acepromazine. Xylazine produced a marked hyperglycaemia in comparison to the other premedicants. Anaesthesia was associated a marked increase in pulse rate and slight increase in haematocrit, but these changes were not markedly affected by the premedication given. Recovery from anaesthesia was deemed to be the most stressful period of short-term general anaesthesia.     

Effects of tolazoline and yohimbine on xylazine-induced central nervous system depression, bradycardia, and tachypnea in sheep

We compared the ability of tolazoline and yohimbine to antagonize xylazine-induced central nervous system depression, bradycardia, and tachypnea in 9 ewes and 5 rams. Once a week for 3 weeks, each sheep received one IV treatment of 0.4 mg xylazine/kg, 0.4 mg xylazine/kg followed in 10 minutes by 2 mg tolazoline/kg, or 0.4 mg xylazine/kg followed in 10 minutes by 0.2 mg yohimbine/kg. The order of the 3 treatments in each sheep was randomized. Xylazine alone caused recumbency for 41.0 +/- 3.7 minutes (mean +/- SEM). Tolazoline and yohimbine shortened the xylazine-induced recumbency to 12.1 +/- 0.9 minutes and 18.1 +/- 1.5 minutes, respectively. Sheep given xylazine alone had head droop for 34.0 +/- 5.4 minutes after rising. Head drooping of sheep given tolazoline or yohimbine was reduced to 10.1 +/- 1.7 minutes and 14.2 +/- 1.7 minutes, respectively. Both tolazoline and yohimbine reversed the bradycardia and tachypnea that followed xylazine administration. No statistical differences in the rate and magnitude of the reversal were observed between the 2 drugs.     

柴达木改良绒山羊红细胞钾型的研究

采用火焰光度法对94只柴达木改良绒山羊的红细胞钾型进行了调查研究。结果发现：（1）柴达木改良绒山羊红细胞钾浓度存在多态性，有高钾和低钾两种表型，以高钾型为优势表型（79．79％）；（2）高钾型山羊的红细胞钾浓度在37－83.2mmol/L之间，低钾型的在16－28．8mmol/L之间；（3）K^L和K^h等位基因频率分别为0．1068和0．8932，基因杂合度为0．1782。     

Dry matter intake and digestion of alfalfa harvested at sunset and sunrise

The preference exhibited by animals in selecting one feed over another is important only if the preferred diet is consumed daily in larger quantities, digested to a greater extent, or both. Six alfalfa (Medicago sativa L.) hays were harvested in pairs at sunset (PM) and sunrise (AM) on consecutive days at three harvest dates. A previous study of these hays demonstrated differences in ruminant preference favoring PM harvests. This study evaluated the effects of time of cutting and harvest date on voluntary DMI and nutrient digestibility. The hays were field-cured, baled, and chopped before evaluation for intake and digestibility. Studies were conducted for sheep (Ovis aries), goats (Capra hircus), and cattle (Bos taurus). Goats, but not steers or sheep, demonstrated differences in nutrient digestibility between PM- and AM-cut hays. Goats consumed more PM than AM hay (2.97 vs. 2.83 kg/100 kg of BW; P = 0.07) and digested it to a greater extent (0.710 vs. 0.696; P = 0.03), resulting in greater digestible DMI (2.11 vs. 1.97 kg/100 kg of BW; P = 0.03). Sheep consumed (mean = 2.52 kg/100 kg of BW; P = 0.59) and digested (mean = 0.681; P = 0.25) PM- and AM-cut hays similarly. Steers consumed larger quantities of PM-than AM-cut hay (2.90 vs. 2.62 kg/100 kg of BW; P = 0.11), but digestion did not differ with cutting time (mean = 0.660; P = 0.75). Difference values (composition of fed hay minus composition of orts) indicated that sheep and goats selected from the feed offered similarly, whereas steers selected differently. Difference values for CP averaged 94 and 101 g/kg for goats and sheep and 32 g/kg for steers (P < 0.01), and difference values for NDF averaged 185 and 196 g/kg for goats and sheep and 73 g/kg for steers (P 相似文献   

Comparative pharmacokinetic disposition of closantel in sheep and goats

The pharmacokinetic disposition of closantel was examined following intraruminal (i.r.) or intramuscular (i.m.) administration to adult Merino sheep and to adult and 3-month-old, suckling Angora goats. In adult goats the maximum concentration (C_max) and area under the plasma concentration with time curve ( AUC ) following 3.75, 7.5 and 15.0 mg closantel/kg given i.r. increased with dose however the time of C_max (r_max= 2.6d) in plasma was unaffected by dose rate. The elimination phase (K₁₀) of closantel was monoexponential with a half-life ( t _½) of 4.7d again unaffected by dose rate. Apart from a more rapid absorption phase and earlier T_max following 3.75 mg closantel/kg i.m., pharmacokinetic behaviour was similar to that following i.r. administration at 3.75 or 7.5 mg/kg. Although absorption rate was more rapid in kids after i.r. administration at 7.5 mg/kg, pharmacokinetic disposition of closantel was otherwise similar to that in adult goats. No closantel was detected in milk of treated does or in the plasma of their kids. I.R. closantel at 7.5 mg/kg was more slowly absorbed in goats than in sheep but C_max was similar in both species. However, K₁₀ t _½ was significantly shorter in goats (4d) than in sheep (14d). Faster elimination resulted in an almost three-fold lowering of AUC in goats and could dramatically reduce the sustained action of closantel in this species compared with sheep.     

Comparative pharmacokinetics of ampicillin trihydrate, gentamicin sulphate and oxytetracycline hydrochloride in Nubian goats and desert sheep

In this investigation the pharmacokinetics of three commonly used antibiotics, ampicillin trihydrate (10 mg/kg), gentamicin sulphate (3 mg/kg) and oxytetracycline hydrochloride (5 mg/kg), given intravenously, were each studied in five Nubian goats and five desert sheep. The pharmacokinetic parameters were described by a two-compartment open model. The results indicated that there were significant differences between the two species in some kinetic parameters of ampicillin and oxytetracycline but not gentamicin. Ampicillin elimination half life ( t _1/2β) in goats (1.20 h) was shorter than that in sheep (2.48 h), and its clearance ( Cl ) significantly higher in goats (2921mL/h·kg) compared to sheep (262 mL/h·kg) ( P < 0.01). Ampicillin volume of distribution ( V d_area) was found to be significantly larger in goats (5673 mL/kg) than in sheep (992 mL/kg) ( P < 0.01). For oxytetracycline, the t _1/2β in goats (3.89 h) was significantly shorter than that in sheep (6.30 h) and the Cl value in goats (437 mL/h·kg) was significantly higher than in sheep (281 mL/h·kg). The results suggest that when treating sheep and goats, the pharmacokinetic differences between the two species must be considered in order to optimize the therapeutic doses of ampicillin and oxytetracycline.     

Analgesic and systemic effects of ketamine,xylazine, and lidocaine after subarachnoid administration in goats

OBJECTIVE: To determine the effects of ketamine hydrochloride, xylazine hydrochloride, and lidocaine hydrochloride after subarachnoid administration in goats. ANIMALS: 6 healthy goats. PROCEDURE: In each goat, ketamine (3 mg/kg), xylazine (0.1 mg/kg), lidocaine (2.5 mg/kg), and saline (0.9% NaCI) solution were injected into the subarachnoid space between the last lumbar vertebra and first sacral vertebra (time 0). Analgesic, ataxic, sedative, cardiovascular, and respiratory effects and rectal temperature were evaluated before (baseline) and 2, 5, 10, 15, and 30 minutes after administration and at 30-minute intervals thereafter as needed. RESULTS: Administration of anesthetics induced varying degrees of analgesia. Onset of the analgesic effect was more delayed for xylazine (mean +/- SD, 9.5 +/- 2.6 minutes) than for ketamine (6.7 +/- 2.6 minutes) or lidocaine (3.5 +/- 1.2 minutes). Duration of analgesia induced by xylazine (88.3 +/- 15 minutes) was twice as long as the duration of analgesia induced by ketamine (48.8 +/- 13.5 minutes) but similar to that induced by lidocaine (66.5 +/- 31 minutes). Xylazine induced bradycardia, whereas ketamine caused a nonsignificant increase in heart rate. Xylazine induced a reduction in arterial pressure, whereas ketamine or lidocaine did not affect arterial pressure. CONCLUSIONS AND CLINICAL RELEVANCE: Subarachnoid administration of xylazine in goats resulted in longer duration of analgesia of the tail, perineum, hind limbs, flanks, and caudodorsal rib areas than administration of ketamine or lidocaine. However, xylazine caused bradycardia and respiratory depression. Additional studies are needed to determine whether the analgesia would be sufficient to allow clinicians to perform surgical procedures.     

Cardiovascular and allied actions of xylazine and atropine in the unanaesthetized goat

The cardiovascular effects of xylazine and atropine, separately and in combination, were studied in goats. Methylatropine was used to distinguish between the central and peripheral effects of atropine. Mean arterial blood pressure and heart rate were recorded, and the sedative effect and changes in respiration and salivation noted. Intravenous infusion of xylazine (2.4-80.0 micrograms/kg) decreased mean arterial blood pressure and heart rate in a dose-dependent manner. Single intravenous injections of both atropine sulphate (0.1 mg/kg) and methylatropine bromide (0.05 mg/kg) increased blood pressure and heart rate. After methylatropine, tachycardia lasted twice as long as after atropine. Following atropinization, a potentiated rise in mean arterial blood pressure was present during the infusion of xylazine (80 micrograms/kg). Xylazine-induced bradycardia was reversed by both atropine and methylatropine. The action of atropine is presumed to be primarily peripheral because of the similar effects with methylatropine. Xylazine-induced sedation was dose dependent. At the highest dose the goats were unable to stand for 30-60 min, respiration became irregular with periods of apnoea, and saliva started to drip a few minutes after infusion without increased salivation. Atropine had no visible effect on the sedation, pattern of respiration or saliva dripping effect of xylazine.