驴,骡血气分析初探

对２５头驴、骡进行血气分析，结果表明：驴、骡血液ｐＨ，Ｐｏ＿２，Ｏ＿２ＳＴ，ＨＣＯ，Ｔｃｏ＿２，ＢＥ＿ｂ，ＳＢｃ，ＢＥ＿（ｅｃｆ）在二者之间无显著差异性（Ｐ＞０．０５）；驴血液Ｐｃｏ＿２，和乳酸皆高于骡（Ｐ＜０．０１和Ｐ＜０．０５）；驴、骡的血液ｐＨ为７．４１±０．０３，Ｐｏ＿２为４．９７±０．９７ｋＰａ，Ｐｃｏ＿２为５．２０±０．３９ｋＰａ，Ｏ＿２ＳＴ为７１．２９±９．２５％，ＨＣＯ＿３为２５．９４±１．６８ｍｍｏｌ／Ｌ，Ｔｃｏ＿２为２７．１５±１．７３ｍｍｏｌ／Ｌ，ＢＥ＿ｂ为１．９６±１．７１ｍｍｏｌ／Ｌ，ＳＢｃ为２５．６８±１．３１ｍｍｏｌ／Ｌ，ＢＥ＿（ｅｃｆ）为１．２３±１．８９ｍｍｏｌ／Ｌ，乳酸含量为１．６８±０．６３ｍｍｏｌ／Ｌ。     

Effect of Food Availability on the Physiological Responses to Water Deprivation in Ponies

Six ponies were deprived of drinking water and food and compared over 24 hours with nondeprived ponies, ponies deprived of water but with food available, and ponies deprived of food but with water available. When food was eaten during water deprivation, plasma osmolality rose 4% from 284 mOsm/kg to 295 mOsm/kg. During water and food deprivation, plasma osmolality failed to rise, even over 24 hours, and usually fell. Packed cell volume was higher when food but not water was available. Food and/or water deprivation had no significant effect on plasma protein concentration. When food was available, the ponies drank three times more water (13.1 ± 2.1 kg) than when water but not food was available (3.5 ± 1.4 kg). Blood volume changes were calculated from packed cell volume and plasma protein data, and it was found that blood volume did not change significantly with deprivation. Urine volume did not vary with deprivation, but free water clearance changed significantly, falling when food but not water was available. Under these conditions, blood volume is maintained, but the mechanisms are not clear. When deprived of both drinking water and food, ponies failed to develop the hyperosmolality expected under these conditions. Water deprivation while food is available is a more powerful challenge to water and electrolyte homeostasis than deprivation of both food and water.     

Subspecies Studies: Pharmacokinetics and Pharmacodynamics of a Single Intravenous Dose of Xylazine in Adult Mules and Adult Haflinger Horses

This study reveals the different effectiveness of xylazine in mules compared with horses. Fourteen adult mules (mean body weight ± standard deviation, 466 ± 89 kg) and six adult Haflinger horses (483 ± 39 kg) chosen from a single livestock operation in Germany received 0.6 mg of the α₂-agonist xylazine administered intravenously per kilogram of body weight. Principal pharmacokinetic and pharmacodynamic parameters were determined while the animals received a routine dental treatment. To objectively assess the depth of sedation, a variety of behavioral and clinical parameters were assessed and transferred to a scaled score system. Compared with the Haflinger horses, the depth of sedation in mules differed significantly between 10 and 45 minutes after xylazine administration. In the mule, sedation was good during the first 10 minutes, moderate at 15 minutes, and insufficient at 30 minutes. In the horse, sedation was excellent during the first 15 minutes, moderate at 30 minutes, and insufficient at 45 minutes. Moreover, significant (P < .05) subspecies differences in the pharmacokinetics of xylazine were detected between the mules and the horses. Data analysis followed the two-compartment model, which had a correlation with the measured data of R² = .99. Values for t_1/2β (half-life during elimination), mean residence time, mean residence time_(0-tz) (residence time on last measuring time point above limit of quantification), k₂₁ (velocity constant for distribution from peripheral to central compartment), β (velocity constant during elimination), and B (relative y-intercept) varied significantly between the two subspecies.     

Assessment of the welfare of working horses, mules and donkeys, using health and behaviour parameters

Working animals provide an essential transport resource in developing countries worldwide. Many of these animals are owned by poor people and work in harsh environments, so their welfare is a cause for concern. A protocol was developed to assess the welfare of working horses, mules and donkeys in urban and peri-urban areas, using direct observation of health and behaviour parameters. In this study, 4903 animals used for draught, pack and ridden work in Afghanistan, Egypt, India, Jordan and Pakistan were assessed between December 2002 and April 2003. The data showed that donkeys were more likely than mules or horses to demonstrate avoidance or aggressive behaviour towards an observer, while horses were most likely to make a friendly approach. Fewer than 8% of working equines had abnormal mucous membranes, ectoparasites or poor coat condition. Body lesions occurred predominantly in the areas of the breast/shoulder, withers and girth in all three species, with mules having the highest prevalence of lesions in these areas (22.5, 21.3 and 28.4%, respectively). Among horses and donkeys, the prevalence of these lesions was influenced by the type of work carried out. Lesions on the head, neck, ribs, flank and tail base were seen in less than 10% of animals. Across all three species approximately 70% of animals were thin, having a body condition score (BCS) of 2 or less on a scale of 1–5 (1, very thin; 5, very fat) and more horses were in very thin condition (BCS 1) than mules or donkeys. Over 75% of animals demonstrated limb deformities and abnormalities of gait. The results of this study are being used as the initial stage of a long-term strategy to inform priorities for welfare interventions in working equines and to establish a welfare benchmark. Subsequent stages will rank the welfare concerns identified, assess the contributing risk factors and implement specific interventions to address these risks. Following intervention, success in improving welfare will be measured by repetition of this protocol and comparison with the benchmark.     

Update on Metabolic Diseases Associated With Laminitis in Horses and Ponies

Several recent scientific publications describe some important findings that may further improve our ability to diagnose and manage both equine Cushing's disease (ECD) and equine metabolic disease (EMD). This abstract provides a brief summary of recent findings in ECD and EMD that have immediate application for clinical practice.     

Triglyceride, Insulin, and Cortisol Responses of Ponies to Fasting and Dexamethasone Administration

Ponies were evaluated for their response to feed withholding and exogenous administration of corticosteroids (dexamethasone 0.04 mg/kg intramuscular [IM]) in an attempt to reproduce the hyperlipemia syndrome. Because insulin resistance has been associated with hyperlipemia, all ponies were initially evaluated for insulin response to an oral glucose load and normal dexamethasone suppression of serum cortisol. Four ponies were identified as hyperinsulinemic reflecting insulin resistance. All ponies had suppressed cortisol concentrations following dexamethasone administration. Feed withdrawal resulted in hypertriglyceridemia by 48 hours in all ponies. Very low density lipoprotein-triglyceride (VLDL) fraction was primarily elevated. The administration of dexamethasone failed to increase the degree of triglyceridemia. Although insulin resistance has been proposed as the likely cause of the hypertriglyceridemia in ponies, in this study four of eight ponies were considered to have normal insulin responses and yet still developed hypertriglyceridemia.     

北方农牧交错区奶牛场舍内外有害气体的季节性变化

本试验旨在探究北方农牧交错区牛舍内外有害气体的变化规律,为有效控制奶牛舍有害气体提供理论依据。试验选择内蒙古西部农牧交错区某奶牛场作为研究对象,在一年中四个季节测定牛舍内外的有害气体含量,每季节连续测定三天。结果表明,舍内外有害气体有一定的季节性变化规律;舍内有害气体含量明显高于舍外,但均未超标。     

马、骡蹄角质某些物理性能的测定

对马(20)、骡(10)蹄角质的测定结果表明,硬度、弹性,抗张强度、弹性模量均为蹄壁>蹄底>蹄叉;蹄底的磨耗大于蹄壁;蹄壁的磨擦系数大于蹄底;蹄壁纵向拉伸的抗张强度大于其横向拉伸,强度越大其伸长率越小;在相同压力下,蹄壁侧压弹性模量值大于纵压值,而蹄底侧压模量值则小于纵压值;蹄角质在材料力学上表现为一种各向异性的特点。作者认为,马、骡蹄角质物理性能的差异与蹄病的发生密切相关。     

Serum Amyloid A (SAA) Concentration after Vaccination in Horses and Mules

Serum amyloid A (SAA) is a sensitive acute-phase response (APR) marker in equids. Prominent APRs with elevations of SAA concentrations ([SAA]) have been reported after vaccination. The authors hypothesized that vaccination with an inactivated EHV-1/-4 vaccine would cause increase in [SAA] and antibody responses and that higher [SAA] would be positively correlated with the antibody titer in both equids. Twelve Haflinger horses and 12 mules were included in this longitudinal prospective study. All horses and mules were vaccinated with a commercially available EHV-1/-4 vaccine. Blood was sampled before and after vaccination to measure [SAA] and virus-neutralizing response (VN-T). In horses and mules, significantly higher [SAA] were measured on days 1, 3, and 5 after EHV-1/-4 vaccination; [SAA] on day 1 after vaccination were only measured in animals that developed fever, where mean [SAA] were significantly higher in horses than in mules (horses: 1,365.75 ± 87.64 mg/L, mules: 615.5 ± 153.444 mg/L) (P > .05). Four horses and 2 mules developed fever after vaccination, lasting for ≤24 hours. Increased antibody responses (VN-T) on days 7 and 14 after vaccination were observed in all animals, whereas mules showed higher overall antibody responses. Nevertheless, [SAA] did not correlate with the intensity of the antibody responses (VN-T) stimulated by the vaccine (P < .05). EHV-1/-4 vaccination caused a prominent APR, higher in horses than in mules, but [SAA] did not correlate with antibody responses. Measuring [SAA] after vaccination could help identify severe APRs that may require longer resting intervals before training or competition.     

Analysis of Behaviors Observed During Mechanical Nociceptive Threshold Testing in Donkeys and Horses

The aims of the study were to analyze and compare behaviors in horses and donkeys observed during nociceptive threshold tests with a mechanical stimulus applied to the limb. The purpose was to identify end point behaviors suggesting the animals had perceived the stimulus to be noxious. Six male castrated horses (aged 3–4 years, weighing 415–503 kg) and eight castrated male donkeys (aged 4–9 years, weighing 152.5–170.5 kg) were studied. Video data recorded during mechanical nociceptive threshold test were analyzed by a single observer. Behaviors were classified into short-duration event behaviors and longer duration activity/state behaviors. Frequency of behaviors within a test (event behaviors) and percentage time spent during the test (activity/state behaviors) were calculated. Data were compared between horses and donkeys using Mann–Whitney tests (nonparametric data) or t-test (parametric data). Significance was taken as P < .05. Behaviors during the tests were observed which could indicate the animals perceived the stimulus as noxious. These included flattening ears back against the head, and turning the head (horses) and chewing (donkeys) although these were not consistent across both species. Foot lifts were often preceded by other behaviors which suggests that the foot lift was not purely a reflex withdrawal response. A shift in weight toward the contralateral limb was a consistent prodromal sign for an end point foot lift.     

蛋白酶和益生菌复合制剂对白羽肉鸡生长性能、养分利用率和粪便有害气体排放的影响

本试验旨在研究饲粮中添加蛋白酶和益生菌复合制剂对白羽肉鸡生长性能、养分利用率和粪便有害气体排放的影响.试验选取体重接近、健康的1日龄爱拔益加(AA)肉仔鸡192只,按照体重随机分为2组,每组8个重复,每个重复12只鸡.对照组饲喂基础饲粮,试验组饲喂添加蛋白酶、枯草芽孢杆菌、地衣芽孢杆菌、凝结芽孢杆菌、酵母菌复合制剂的基...     

Physical, Hematological, and Biochemical Responses to Acute Intense Exercise in Polo Horses

The aim of this study was to evaluate the response of physical, hematological, and biochemical parameters after acute intense exercise in polo horses playing in an outdoor international competition. The game consisted of four periods (chukkas) and each period consisted a playing time of 7 minutes. Two matches were played everyday for a week. A total of 12 horses were examined. Each “high-goal” polo horse played one chukka a day for 4 days. Horses were clinically examined the day before the games started and then daily during the 4 days of their participation in the games. During these days, physical examination was performed and blood sample was collected at rest (T0), immediately (T1) after exercise, and after 30 minutes of exercise (T2). Blood samples were analyzed for total cell counts and for determination of creatine kinase, lactate dehydrogenase (LDH), aspartate aminotransferase, lactate, total proteins, calcium, magnesium, phosphorus , and cortisol. Data were evaluated using two-way analysis of variance. Exercise caused significant dehydration (P < .01), mucous membranes congestion, increased heart rate (P < .001), and capillary refill time (P < .001). It also caused increased value of the following parameters: hematocrit (P < .001), red blood cells (P < .001), hemoglobin (P < .001), white blood cells (P < .05), lymphocyte (P < .001), total proteins (P < .001), creatine kinase (P < .05), LDH (P < .01), lactate (P < .001), and cortisol (P < .01), and a decrease in the platelet count (P < .001), calcium (P < .01), phosphorus (P < .001), and magnesium (P < .001). All parameters returned within or near the reference range by 30 minutes postexercise. On the basis of these observations, data were considered indicative of a good response to an acute intense exercise. Moreover statistical results obtained were typical of a mixed aerobic/anaerobic metabolic pathway that is prevailing in this sport.     

Relationship Between Magnitude and Direction of Asymmetries in Facial and Limb Traits in Horses and Ponies

Directionality of limb and facial asymmetries in nonelite equine populations has been previously reported with results indicating strong similarities to those reported in racehorses. This investigation aimed to consider the relationship between the magnitude of the asymmetries presented within the general equine population, and their previously reported directionality. Direct measurements of 15 bilateral traits (four facial and 11 limb) were captured from a mixed population of 100 horses and ponies. The pooled (whole) population was considered further as horse (withers height >148 cm) and pony (withers height ≤148 cm) groupings. Each of the three groups was further subdivided for each trait, into individuals presenting with larger left or larger right sides. Asymmetries were compared as mean asymmetries and as percentages of the trait size at each grouping level. Asymmetry magnitudes were largely reflective of the directional asymmetries previously recorded. Both the horse and pony groups presented with significantly longer right side third metacarpal (P ≤ .001) and third metatarsal (P ≤ .05 and P ≤ .001) bones, whereas in the horse group, the left fore proximal phalanx was both longer and wider than the right (P ≤ .001 and P ≤ .05). This pattern is reflective of the biomechanical preference for left lead anticlockwise canter, previously only observed in racehorses. The proximal phalanx of the forelimb potentially compensates for the higher loading forces associated with the lead forelimb. When scaled as percentages of trait size, the asymmetry magnitudes largely reflected those reported in humans, suggesting similar measurement criteria could be applied when considering stock selection and controlling for injury predisposition in horses.