Clinical, cardiopulmonary and haemocytological effects of xylazine in goats after acute exposure to different environmental temperature and humidity conditions

This study was carried out to assess the influence of xylazine administration on clinical, cardiopulmonary and haemocytological variables after acute exposure to different environmental conditions. Xylazine hydrochloride was administered intravenously at 0.1 mg/kg body mass to 6 clinically healthy, castrated male goats. All animals were exposed for 60 min to 3 sets of climatic conditions: 14 degrees C, 33% relative humidity; 24 degrees C, 55% RH, and 34 degrees C, 65% RH. The variables that were measured for a period of 60 min after xylazine administration were sedation, analgesia, salivation, urination, ventilation rate, heart-rate, mean arterial blood pressure, oesophageal temperature, haematocrit, mean corpuscular volume and mean corpuscular haemoglobin concentration. Xylazine induced sedation, analgesia, salivation and urination independently of the 3 environmental conditions. Environment had no influence on the onset, duration and recovery from sedation. In the 14 degrees C environment, xylazine resulted in a significant decrease in ventilation and heart-rate from baseline values. Significant changes in mean arterial blood pressure, haemoglobin concentration, mean corpuscular volume, haematocrit and red cell count were observed in the 3 environments. Total plasma protein was significantly altered at 24 degrees C and 34 degrees C. Acute exposure of goats to different environmental conditions had no significant influence on the clinical, cardiopulmonary and haemocytological variables. Physiological changes induced by xylazine were therefore independent of the environment.     

The effect of propofol on acid-base balance and ionic composition of venous and arterial blood in goats

The aim of the present study was to determine the effect of propofol on acid-base balance and ionic composition of arterial and venous blood in clinically healthy goats. The experiment was performed on ten adult goats. Propofol was administered intravenously at bolus dose of 6 mg/kg bw. The heart and breath rate, acid-base balance (pH, pCO2, pO2, HCO3-, BE, O2SAT, ctCO2) and ionic composition (Na+, K+, Cl-) of arterial and venous blood were measured before injection and 3, 6 and 15 min. after. The propofol infusion induced increase of heart rate, decrease of breath rate and compensated respiratory acidosis in venous and arterial blood. It was found that changes of acid-base balance parameters in arterial blood arose faster than in venous blood. The levels of sodium and chloride ions in both types of blood were similar, whereas the level of potassium ions was higher in venous blood during entire experiment.     

Effects of xylazine on the stress response to transport in male goats.

A 20-min van journey increased plasma cortisol concentrations to 15-25 ng/ml in male goats, blood glucose concentrations were not affected, but respiratory rates and heart rates were increased, the latter by 40 beats per min. A 2-h van journey increased plasma cortisol to greater than 25 ng/ml and blood glucose to greater than 5 mmol/l. Respiratory rates were increased to greater than 40 breaths per min and heart rates by greater than 100 beats per min. Xylazine alone (0.01 mg/kg) suppressed resting plasma cortisol concentrations, increased blood glucose concentrations to 4.5 +/- 0.8 mmol/l and suppressed respiratory rates by 5-10 breaths per min and heart rates by 20 beats per min. Cortisol concentrations were suppressed by xylazine treatment if given before a 20-min van journey, and for approximately 60 min if given 20 min after the start of a 2-h journey. When combined with transport, xylazine caused an additive effect on glucose concentrations, but suppressed respiratory and heart rates. However, for the latter criteria the timing of suppression was different depending on the time of onset and duration of the stressor. Injection of 50 micrograms ovine corticotrophin releasing factor (CRF) caused an immediate elevation of cortisol concentrations (but not glucose) which lasted for at least 6 h compared with the return to baseline within 60 min after either length of journey. Xylazine pretreatment did not alter the cortisol response to CRF, suggesting that xylazine must act centrally above pituitary level when blocking the cortisol response to transport. It is proposed that under resting conditions the hypothalamus is under alpha 2-adrenergic suppression. Stimulation of cortisol secretion in response to a stressor can be inhibited by an alpha 2-adrenergic agonist.     

Effects of dietary cation-anion balance on acid-base status in horses

Four mature, sedentary geldings were used in a 4x4 Latin square design experiment to study the effects of dietary cationanion balance (DCAB), defined as meq ((Na + K) - C1)/kg of dietary dry matter, on urine pH, blood pH and blood gasses. Four diets with actual DCAB levels of +21 (Low, L), +125 (Medium Low, ML), +231 (Medium High, MH) and +350 (High, H) were fed for a 21-day adjustment period and a 72 hour collection period. Total urine output was collected every 4 hours post feeding for 72 hours, and like times across days were combined for analyses. Arterial and venous blood samples were drawn, via indwelling catheters, hourly for 12 hours beginning at feeding. All samples were analyzed immediately after collection for pH, blood gasses and blood acid-base measures. Urine pH was lower (p<.05) at all measured intervals when geldings consumed diet L than when they consumed diets MI, MH and H. Least squares means for urine pH ranges from 5.40 to 5.86 on diet L, 6.79 to 7.30 on diet ML, 7.35 to 7.63 on diet MH and 7.52 to 8.14 on diet H. Blood pH, pCO₂ and HCO₃ values were also significantly lower in both arterial and venous samples when geldings consumed diet L than when fed diets MH and H. Results of this trial indicate that horses consuming highly anionic diets may experience a nutritionally-induced metabolic acidosis.     

饲粮不同氯水平对笼养生长蛋鸭体内酸碱平衡的影响

本试验旨在研究玉米-豆粕型饲粮不同氯水平对笼养生长蛋鸭体内酸碱平衡的影响。选用300只28日龄体重相近的金定鸭,随机分为5个处理组,分别饲喂含氯0.06%、0.12%、0.18%、0.30%和0.60%的饲粮,每个处理组设10个重复,每个重复6只蛋鸭。结果显示:各处理组之间血清Cl-含量和Na+含量随饲粮氯水平的升高呈线性增加;各组间血液pH和HCO3-浓度差异不显著(P0.05),但是随氯水平增大血液逐渐趋于酸性。综合分析,低水平或高水平的氯可影响蛋鸭体内的酸碱平衡,饲粮中含0.12%～0.18%的氯可使笼养蛋鸭体内达到最佳的酸碱平衡。     

Effect of temperature and humidity on sperm morphology in duroc boars under different housing systems in Thailand

The aim of this study was to investigate the effect of season, temperature, humidity, age of the boar, and semen collection interval on sperm morphology in Duroc boars in Thailand, kept either in a conventional open air system (CONV) or in an evaporative cooling system (EVAP). In total, 1176 ejaculates from 110 sexually mature boars in six CONV herds and five EVAP herds were morphologically examined during a one-year period. Analysis of variance was applied to the data. Minor differences in the sperm morphology traits analyzed were found between the housing systems. There was a significant seasonal effect (two-month periods) on the percentage of morphologically normal spermatozoa (normal1), morphologically normal spermatozoa including spermatozoa with distal cytoplasmic droplets (normal2), proximal cytoplasmic droplets (prox), and sperm head abnormalities (P相似文献   

Leptospirosis in sheep and goats under tropical conditions

Inadequate management practices and poor reproductive performance have been reported as fundamental factors on reducing the levels of productivity in livestock. Different pathogens have been reported in small ruminants' herds/flocks with reproductive failures. The aim of the present study was to review aspects of leptospirosis in small ruminants, mainly its impact on reproduction and consequently on productivity of the herds/flocks under tropical conditions. Leptospiral infection in goats and sheep is common in several countries, and those species can also act as carriers of leptospires. Severe disease is often associated to young animals and is frequently associated to incidental serovars. In contrast, subclinical infection is mainly characterized by reproductive problems, such as infertility, abortion, occurrence of stillbirths, and weak lambs/goat kids. Moreover, laboratorial tests are essential to achieve an accurate diagnosis of the infection. Microscopic agglutination test is the most common indirect test of leptospirosis, being used worldwide. In small ruminants, PCR consists on a recommendable method for diagnosing animals that carry leptospires. Control of leptospirosis in small ruminants involves measures such as the identification and treatment of the carriers and other sources of infection, quarantine in acquired animals, and systematic immunization with commercial vaccines containing the circulating serovars in the herd/flock. Productivity of small ruminant breeding can dramatically increase with adequate sanitary conditions and control of leptospirosis. Immunization of all the animals combined to the treatment of carriers may successfully control the infection and importantly reduce the economic reproductive hazards that are observed under tropical conditions.     

Effect of xylazine in heifers under thermoneutral or heat stress conditions

A study was performed to assess the effect of xylazine HCl (0.1 mg/kg of body weight, IV) in heifers maintained at thermoneutrality (18 C, 42% humidity) or under heat stress (33 C, 63% humidity) conditions. Xylazine caused 50 and 70% decreases in serum insulin concentrations in the thermoneutral and heat-stressed heifers, respectively. Xylazine-induced hypoinsulinemia was associated with hyperglycemia. In the thermoneutral group, serum glucose concentrations increased from a basal concentration of 75 mg/dl to 150 mg/dl after 15 minutes. In the heat stress group, the serum glucose concentration increased from 65 mg/dl to 105 mg/dl. Hyperglycemia peaked at 2 hours and remained high for 6 hours after xylazine administration. Heat-stressed heifers took a longer time (107 minutes) to stand than did heifers under thermoneutral conditions (41 minutes). The time to regain sensation to pain was significantly prolonged in heat-stressed heifers. Xylazine had no effect on body temperature and respiration rate in heifers under the thermoneutral condition, whereas it markedly induced hyperthermia and suppressed respiration rate in the heat-stressed heifers. Furthermore, the pulse rate was slightly decreased in thermoneutral heifers and was markedly decreased in the heat-stressed heifers.     

Dynamics of the acid-base balance of venous and arterial blood in clinically healthy calves]

Values of the acid base balance were examined in both venous and arterial blood of healthy calves (n = 6) of the Slovak Spotted breed aged, 3, 6, 8, 10, 12, 14, 18, and 24 weeks, respectively. Until week 4 of age the animals were fed milk only, until the age of 9 weeks a milk-roughage transition fodder and from week 10 on they were given classical herbage. Blood samples were taken from the V. jugularis and A. carotis communis or A. axillaris, respectively. The results achieved were corrected to a body temperature of 39 degrees C. During the examination period the following values were stated for both arterial and venous blood: actual acidity (pH) 7.391 +/- 0.014 and 7.362 +/- 0.013 logmolc, pCO2 6.35 +/- 0.15 and 7.35 +/- 0.11 kPa, HCO3-28.38 +/- 1.42 and 30.32 +/- 1.02 mmol. l(-1), ABE 3.57 +/- 1.44 and 4.34 +/- 1.09 mmol. l(-1); pO2 12.63 +/- 1.15 and 5.21 +/- 0.73 kPa, SAT 95.8 +/- 1.03 and 61.2 +/- 9.59%, respectively. A gradual increase in most indices of the acid base balance could be stated both in arterial and venous blood. The trends either revealed a parallel increase (HCO3-, pH) or they were more pronounced either in venous blood (SAT) or in arterial blood (ABE, pO2). Some trends were almost balanced (pCO2 and pO2 in venous blood and SAT and pCO2 in arterial blood). Thus pH, pO2 and SAT indices of the acid base balance were higher in arterial blood as compared to venous blood while pCO2, HCO3- and ABE values were higher in venous blood.(ABSTRACT TRUNCATED AT 250 WORDS)     

Growth and carcass traits of Creole goats under different pre-weaning,fattening and slaughter conditions

Data of 198 male Creole kids were analysed to assess the main non-genetic sources of variation of their meat abilities. Basal diet was composed of tropical pasture (28 days): in FD (forage diet), kids received no supplement; in group MD (mixed diet) they were offered 360 g/day pellet, while in group PD (pasture diet) kids were reared at pasture without supplementation. Given a regular four-month interval of weaning within the flock, fixed ages at slaughter (AS) were 7, 11 and 15 months. Three slaughter weights (SW) were compared 17–18, 21–22 and 25–26 kg. The growth levels before weaning and the season of birth effects were added in the statistical analysis. The use of MD has a significant (P < 0.05) effect on almost all the body and carcass traits: 85% more ADG and carcass weight. The weights of fat tissues increased but represented only 4% of empty body weight. As expected, there were significant (P < 0.05) differences within the SW and AS classes that are discussed. Range of variations allow for suggesting further experiments or practical recommendations. The initial results: carcass yield (55%), conformation score (more than 3), fat cover score (less than 3), proportion of primal cuts (63%) or muscle/bone ratio (3–4 points) are a good incentive for the local sector.     

The effect of arterial blood sampling sites on blood gases and acid-base balance parameters in calves.

In 21 healthy calves, 1-6 months old, the interrelationship and comparability of acid-base balance variables (pH, HCO3-, BE) and blood gases (pCO2, pO2, and sat-O2) were evaluated in arterial blood collected from a larger, centrally localised (the a. axillaris) and a smaller peripheral artery (the a. auricularis caudalis). Sampling was done by direct puncture of the vessels without local anaesthesia. Except for blood pH, significant differences were observed in the average values of pCO2, pO2, HCO3-, sat-O2 (P < 0.001), and BE (P < 0.05). Analyses of blood from the a. axillaris showed higher pH, pO2, and sat-O2 values, and lower pCO2, HCO3-, and BE values compared with that from the a. auricularis caudalis. Despite statistically significant differences between some variables, in all indices high and significant correlation relationships were recorded (R = 0.928-0.961; P < 0.001). Therefore, from the biological and clinical point of view, these differences are unimportant and the presented method of peripheral arterial blood sampling can be considered suitable for evaluating blood gases and acid-base status.     

Acid-base balance parameters and ionic composition of arterial, venous and capillary blood in goats

The aim of the present study was to compare the acid-base balance parameters of arterial, venous and capillary blood in clinically healthy goats, and to determine the electrolyte content of venous and arterial blood. The experiment was performed on ten adult goats. It was found that the acid-base balance parameters of venous blood differed from those of arterial blood, whereas the parameters of capillary and arterial blood were similar. The levels of sodium and chloride ions in arterial and venous blood were similar, whereas the level of potassium ions was higher in venous blood.     

日粮不同非蛋白氮水平条件下异位酸对山羊瘤胃发酵的影响

试验利用体外产气法研究日粮不同非蛋白氮水平条件下异位酸对山羊瘤胃发酵的影响。试验采用单因子设计,非蛋白氮(NPN)设置4个添加水平,分别为0(对照组)、0.5%、1.0%、1.5%,每个水平设4个重复,复合异位酸添加水平为0.3%。体外连续培养24h,测定24h累计产气量、细菌氮含量和中性洗涤纤维(NDF)降解率。试验结果表明,各组间累计产气量差异均不显著(P>0.05),但是1.0%组和1.5%组的累计产气量有增加的趋势;各组间细菌氮含量差异均不显著(P>0.05),但是随着NPN添加水平的提高,细菌氮含量有降低的趋势;各处理组的中性洗涤纤维(NDF)降解率与对照组比较差异极显著(P<0.01),添加0.5%、1.0%、1.5%非蛋白氮的试验组NDF降解率分别降低了6.62%、11.50%和13.16%。总体来看,在本试验条件下,不同非蛋白氮水平条件下,0.3%异位酸并没有起到改善瘤胃发酵的作用。