Anatomical variation of arterial supply to the rabbit spleen

The rabbit, which is widely used as an experimental animal and is also popular as a companion animal, has aflat and elongated spleen with the longitudinal hilus running along its visceral surface. The spleen receivesvia the hilus an arterial supply that is essential for splenic nutrition and normal functioning. However, thedistribution and variation of the arteries to the spleen have not been studied in detail. This studyinvestigated anatomical variations of splenic arterial supply in 33 New Zealand White rabbits with a coloredlatex injection into arteries. We also examined whether the length of the spleen correlated with the number ofthe splenic branches of the splenic artery. The splenic artery always arose as the first independent branch ofthe celiac artery and ran along the splenic hilus to usually provide 6 (range, 3 to 10) splenic branches tothe spleen. There was a moderate correlation (R=0.6) between the number of splenic branchesand the longitudinal length of the spleen. The splenic branches often arose as a trunk or trunks in commonwith short gastric arteries. The number of common trunk(s) was usually 1 (range, 0 to 4). The data showed thatthe pattern and number of arterial branches to the spleen varied according to the individual animal,suggesting that such variations should be considered when performing experimental and veterinary surgicaltreatments in rabbits.     

Abdominal ultrasonography in small animals: Examination of the liver, spleen and pancreas

Ultrasonography is an important diagnostic technique in veterinary medicine. It may be used to examine most structures in the small animal ahdomen, providing a rapid, non-invasive means of supplementing information obtained by physical examination and radiography. Limitations of ultrasonography include the non-specific nature of many observed abnormalities, which prevents a specific diagnosis, and the difficulty of identifying certain normal organs such as the pancreas. This paper reviews ultrasonography of the liver, spleen and pancreas, and ultrasound-guided biopsy in small animals, and indicates areas of potential future development.     

Assessment of the accuracy of estimation of gestational age in cattle from placentome size using inverse regression

AIMS: To assess, in dairy cows between 60–160 days of gestation, whether the agreement between actual gestational age and that predicted by placentome size could be improved by using individual placentome measurements rather than a single average, and to identify how increasing the number of placentomes measured improved the prediction.

METHODS: Data were obtained from 58 cows examined using transrectal ultrasonography every 10 days between 60–130 days, and every 15 days between 130–160 days of gestation. For each cow, four to six placentomes in each of the pregnant and non-pregnant horns were examined from the region of the uterus near to the cervix. A mixed-effects model, which included cow as a random effect, and a simple linear regression which ignored within-cow correlation, were fitted to the data. Inverse regression was used to compare the 95% prediction bands obtained for estimating gestational age using the means of three, five or eight placentome measurements.

RESULTS: The fit of the mixed effects model was better than a simple linear regression (p<0.001) but the fitted lines from the two models were very similar. Using the simple regression model, for a mean placentome length of 15?mm estimated gestational age was 100 days, with 95% CI of 68–131 days for measurement of three placentomes, and 80–120 days for eight placentomes.

CONCLUSIONS: The agreement between placentome size and gestational age was improved by increasing the number of placentomes measured. Direct comparison of these CI with those for other published fetal measures was not possible as similar prediction bands have not previously been calculated for fetal measures; however one study reported a residual SD which had been calculated using size measurements as the predictor variable and age as the response variable. Using these data 95% CI were calculated to be ±9 days for crown-rump length and ±25 days for uterine diameter. These are likely to be an underestimate of the true CI and do not take account of the increase in variance of the difference between predicted and actual gestational age as gestational age increases.

CLINICAL RELEVANCE: Placentome measurement may be useful for estimating fetal age in late gestation. Further research is required to better establish the agreement between gestational age and the fetal measurements which are currently used to estimate fetal age.     

兔脾淋组织液对猪瘟疫苗的免疫增强试验

猪瘟 ( HC)是养猪业中造成重大损失的急性传染病 ,它被国际兽医局 ( OIE)列入 1 6种 A类法定传染病之一。尽管每年我国都投入大量的人力物力进行猪瘟疫病的防疫和科研工作 ,使该病得到了较大程度的控制 ,但近年来仍有猪瘟发生 ,尤以小猪多见。在生产中采取乳前免疫或加大免疫剂量的免疫方法 ,仍然有抗体水平未达到最低保护线 ( 1∶ 32 ,IHA法 )的猪只存在。据广西部分大型猪场反映 ,虽然猪瘟兔化弱毒犊牛睾丸细胞苗加大到 4个剂量仍难以控制该病的发生 ,而改用兔脾淋组织液后却收收稿日期 :2 0 0 1-0 3 -3 1到理想的效果。本试验的目的…     

Assessment of ketamine and medetomidine anaesthesia in the domestic rabbit

OBJECTIVE: To study the effects of ketamine and two doses of medetomidine administered by two routes of injection in a genetically diverse population of rabbits. STUDY DESIGN: Prospective, randomized, clinical trial. ANIMALS: One hundred and five domestic rabbits of mixed breed, sex and age. MATERIALS AND METHODS: Rabbits undergoing orchiectomy or ovariohysterectomy received ketamine (15 mg kg(-1)) combined with medetomidine at 0.25 or 0.5 mg kg(-1), by subcutaneous (SC) or intramuscular (IM) injection. Anaesthesia was supplemented with 1.5-2% isoflurane when signs of regular jaw movements and/or slight limb twitching indicated inadequate anaesthesia. Heart and respiratory rate, blood oxygen saturation, end-tidal carbon dioxide concentration and rectal temperature were monitored at several time points. Duration of surgical anaesthesia and anaesthesia time were measured. At completion of surgery, atipamezole (1.0 or 0.5 mg kg(-1), IM or SC) was administered. STATISTICAL ANALYSES: MANOVA was used to compare variables over time between males and females, anaesthetic doses and routes of drug administration. RESULTS: All reflexes were lost significantly more rapidly after IM drug administration (p < 0.05). The times (in minutes) from drug injection to loss of reflexes for the respective groups were: righting reflex: 6.3 (15.0 + 0.25, SC), 5.5 (15.0 + 0.5, SC), 2.9 (15.0 + 0.25, IM) and 2.3 (15.0 + 0.5, IM); ear pinch: 9.2, 8.5, 4.8, 3.6; pedal withdrawal: 12.8, 10.4, 6.6, 5.2. Heart and respiratory rates during surgery did not differ between groups, however the highest end-tidal CO(2) concentration during surgery was significantly affected by dose, with the highest concentration occurring in group 15.0 + 0.5 IM. The number of animals requiring isoflurane tended to decrease with increasing dose of anaesthetic and significantly more females required supplementation than males (p < 0.05). Recovery from anaesthesia (return of righting reflex) was not significantly different between dose groups (p > 0.1) but was more rapid in animals given IM atipamezole (13.6 +/- 13 versus 21 +/- 17, p = 0.037). No anaesthetic-related mortality occurred and all but three animals recovered uneventfully. Five animals were killed whilst under anaesthesia because of unrelated disease. CONCLUSION AND CLINICAL RELEVANCE: Ketamine-medetomidine combinations reliably produced surgical anaesthesia in domestic rabbits that could easily be deepened for brief periods with low concentrations of isoflurane. Subcutaneous administration was better tolerated, but the speed of induction was slower compared with IM injection. Atipamezole was an effective antagonist and produced most rapid effects when administered IM.     

Assessment of the analgesic action of opioid agonist-antagonists in the rabbit

The analgesic actions of buprenorphine, butorphanol, nalbuphine and pentazocine were assessed in the rabbit by analgesiometry using a thermal stimulus. All four compounds produced effective analgesia without causing serious respiratory depression. Increased dose rates of buprenorphine, butorphanol and nalbuphine produced only a minor increase in the maximum degree of analgesia attained. At the highest dose rates of nalbuphine and butorphanol which were assessed there appeared to be a reduction in the degree of analgesia and its duration of action whereas increased dose rates of buprenorphine produced progressively longer periods of analgesia (0.0075mg/kg - 150min; 0.03mg/kg -660min; 0.3mg/kg - >780 min). The results indicate that these opioids can be used safely to provide pain relief in rabbits, provided that excessively high dose rates of nalbuphine and butorphanol are avoided.     

阿维菌素驱除兔蛲虫试验报告

朝阳市近年养兔业得到了很大发展,兔寄生虫病对养兔业的危害已引起人们重视。在朝阳市兔体寄生虫调查中发现,兔蛲虫对兔的感染率很高,从外贸冷冻加工厂、康宁医院兔场、朝阳县一粮库兔场、龙城区西大营子集市、双塔区凌北集市购入的233只兔剖检所得,兔蛲虫感染率为81.1%(189/233),感染强度为50(2~1 220条),感染兔均有不同程度的肠炎变化,严重感染者毛焦、消瘦,生长缓慢,易继发其它疾病,严重影响养兔的经济效益,对养兔业发展造成威胁。为寻求一种较好的驱治兔蛲虫的药物,2005年9~10月作者利用康宁医院兔场和航发兔场饲养的兔及从市郊各集市购…     

Assessment of ultrasonography and computed tomography for the evaluation of unilateral orbital disease in dogs

OBJECTIVE: To describe clinical, ultrasonographic, and computed tomographic (CT) features of confirmed neoplastic and nonneoplastic disease in dogs with unilateral orbital diseases, determine criteria to differentiate between the 2 conditions, and assess the relative value of ultrasonography and CT for the differential diagnosis of these 2 conditions. DESIGN: Prospective study. ANIMALS: 29 dogs with unilateral neoplastic orbital disease and 16 dogs with unilateral nonneoplastic orbital disease. PROCEDURES: Clinical history and results of physical and ophthalmologic examinations were recorded. Ultrasonographic and CT images were evaluated, and discriminating factors were identified to differentiate neoplastic from nonneoplastic diseases. Diagnostic value of ultrasonography and CT was assessed. RESULTS: Dogs with neoplastic disease were significantly older; had clinical signs for a longer time before initial examination; had more progressive onset of clinical signs; and more frequently had protrusion of the nictitating membrane, fever, and anorexia. The most discriminating factor for both imaging modalities was delineation of the margins (odds ratio was 41.7 for ultrasonography and 45 for CT), with neoplastic lesions clearly delineated more often. Ultrasonographically, neoplastic lesions were more frequently hypoechoic and homogeneous, with indentation of the globe and bone involvement evident more frequently than for nonneoplastic lesions. Mineralization was detected only with neoplasia. Fluctuant fluid was seen more frequently in dogs with nonneoplastic disease. Computed tomography more frequently revealed extraorbital involvement. Diagnostic value was similar for both imaging modalities. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonography and CT are valuable imaging modalities to assist in differentiating neoplastic from nonneoplastic unilateral orbital disease in dogs.     

Assessment of ketamine/medetomidine anaesthesia in the New Zealand White rabbit

Objective To compare the characteristics of anaesthesia induced with four dose combinations of ketamine/medetomidine. Design Prospective randomized study. Animals Five female New Zealand White (NZW) rabbits of approximately 2.3 kg. Methods Rabbits were given one of four drug combinations (25/0.25; 15/0.5; 15/0.25 and 10/0.5 mg kg^?1 IM) on four successive occasions with a four day interval. Response to injection and then arterial blood gas and cardiovascular parameters were recorded at predetermined time points. Toe and ear pinch reflexes gave measures of total duration of surgical anaesthesia and total sleep time. Analyses used repeated measures analysis of variance. Results Induction was smooth with little reaction to injection and intubation achieved easily. Two combinations (15/0.25, 10/0.5) produced moderate hypoxaemia (mean pO₂ < 8.0 kPa) and two (25/0.25, 15/0.5) very marked hypoxaemia (mean pO₂ < 5.3 kPa). This was reversed within 15 minutes of oxygen administration and all rabbits recovered uneventfully. Heart rates fell in all cases, with only minimal effects on arterial blood pressure and no cardiac arrhythmias. Mean duration of surgical anaesthesia was significantly longer for dose groups 25/0.25 (57 ± 12 minutes) and 15/0.5 (59 ± 17 minutes, p = 0.01) compared to dose group 15/0.25 (27 ± 8 minutes). Only three animals in the 10/0.5 mg kg^?1 group achieved surgical anaesthesia. Mean duration of loss of the ear pinch reflex was similar between doses, being, respectively, 64 ± 13, 81 ± 7, 60 ± 22 and 62 ± 24 minutes. Sleep time was significantly longer for the 15/0.5 dose (112 ± 10 minutes) compared to 15/0.25 (86 ± 22 minutes, p = 0.04). Sleep times for the 25/0.25 and 10/0.5 mg kg^?1 doses were, respectively, 103 ± 23 and 108 ± 12 minutes. Conclusions Ketamine/medetomidine reliably produces smooth induction and recovery in the NZW rabbit, but due to the degree of hypoxaemia produced, should only be used with simultaneous provision of oxygen. Clinical relevance Currently recommended dose rates of ketamine/medetomidine for minor procedures such as ovariohysterectomy in rabbits (25 mg/0.5 mg kg^?1) are unnecessarily high; a dose of 15/0.25 mg kg^?1 should be adequate for 15–30 minutes of surgical anaesthesia.     

微生物制剂对幼兔腹泻治疗的研究

本实验从健康家兔肠道正常菌群中经分离、鉴定,筛选出3种有益菌种:需氧芽孢杆菌、酵母菌和厌氧乳酸杆菌,经安全试验和药物敏感试验合格后,分别发酵培养,制成复合型微生物制剂再应用到断奶幼兔中,观察对幼兔体重、消耗饲料量、腹泻发生率等的影响,同时应用微生物制剂治疗腹泻兔,观察其治疗效果。实验表明,应用复合微生物制剂增重效果明显,料肉比分别为4.20:1,50日龄和70日龄的成活率分别为96%和90.67%,第50日龄和第70日龄时腹泻率为1.33%和4.67%。使用兔源菌种制成的Ⅰ型微生物制剂能够减少家兔的耗料量,体重明显增加,显著降低料肉比;能够较好地预防幼兔腹泻的发生和降低死亡只数,并且制剂的菌种对大多数抗生素没有抗药性,具有促进生长、减少或杜绝药物污染的优点。     

Measurement of tracheal diameters using ultrasonography versus computed tomography in Beagle dogs

ObjectiveTo compare ultrasonography with computed tomography (CT) for assessment of tracheal diameter as a feasibility study for endotracheal tube selection.Study designProspective study.AnimalsA total of nine Beagle dogs with a median (interquartile range) weight of 7.4 (7.2–7.7) kg.MethodsTracheal diameter measurements were obtained at two locations: 1 cm proximal to caudal border of the cricoid cartilage (sublaryngeal; SL) and dorsal to above cranial border of the manubrium (thoracic inlet; TI). For CT, dogs were anesthetized with propofol and sevoflurane, in sternal recumbency, and measurements obtained after controlled ventilation–induced apnea and the endotracheal tube cuff was deflated. Transverse diameter, right and left 45° oblique diameters were measured. For ultrasonography, unsedated dogs were standing with slight neck extension, and images obtained in ventrodorsal, 45° right and left oblique ways after expiration. Diameters between the tracheal lumen mucosal borders were measured. The degree of agreement between the tracheal diameters measured at SL and TI locations with CT (TD_CT-SL and TD_CT-TI) and ultrasonography (TD_US-SL and TD_US-TI) was verified using the Bland-Altman method.ResultsThe agreement between the measurements obtained with CT and ultrasonography was revealed by Bland-Altman analyses, although ultrasonography tended to slightly underestimate the tracheal diameter.Conclusions and clinical relevanceUltrasonography can be applied for tracheal diameter measurement. Although further studies are required, an endotracheal tube selection method, using ultrasonography, could be proposed.     

Assessment of fetal well-being in cattle by ultrasonography in normal, high-risk, and cloned pregnancies

This study determined ultrasonographic parameters of fetuses and uterine adnexa in late pregnancy in normal, cloned, and high-risk pregnancies in relation to perinatal and neonatal outcome. Ten cows with normal pregnancies (CONTROL, mean pregnancy length 273 d), 10 sick cows with potentially compromised pregnancies (HIGH-RISK, mean pregnancy length 267 d), and 10 heifers with cloned pregnancies (CLONED, mean pregnancy length 274 d) were examined at more than 260 d of gestation. There was no difference in mean fetal heart rates among the groups. The cloned calves were heavier (57 ± 8 kg) than calves from CONTROL group (36 ± 7 kg), and calves from HIGH-RISK group (37 ± 13 kg) (P = 0.003). The diameter of the thoracic aorta was positively correlated (R = 0.62) with fetal birth weight in the CONTROL group (P = 0.01). Fetal activity was not associated with survival. The results suggest that transabdominal ultrasonographic assessment of the fetal well-being may serve as a potential tool for evaluation of the fetoplacental unit.     

应用灰色关联度法对肉兔产仔数与相关性状关联度的探讨

本文结合肉兔产业基地生产,获取了肉兔开产1～3胎的平均产仔数与相关性状,通过灰色关联度分析,初步看出与产仔数关联度高的性状依次是体长〉体重〉耳长〉耳宽,说明在开产早期选择体长、发育好的母兔个体对提高产仔数有实际意义。