CONGENITAL CEREBELLAR HYPOPLASIA IN JERSEY CALVES

Congenital cerebellar hypoplasia and hydrocephalus is reported in 8 Jersey calves. The possible relationship between this entity and BVDMD virus is discussed.     

CEREBELLAR HYPOPLASIA OF GENETIC ORIGIN IN CALVES

Within 2 years, following the introduction of 2 Shorthorn bulls from the same stud into an Australian Illawarra Shorthorn (AIS) herd, 16 calves were born with cerebellar hypoplasia. All affected calves were the progeny of one bull mated to the daughters of the other. All other progeny of these bulls, most of which were from AIS dams, were normal. Affected calves exhibited severe ataxia, consistent head movement and abduction of the forelimbs. Microscopic changes in the cerebellum included sparsity of cells of the granular layer, loss of Purkinje cells and narrowing of the molecular layer. Observations on the frequencies of normal and abnormal calves are consistent with the hypothesis that the condition is caused by an autosomal recessive gene for which affected calves were homozygous and which was introduced into the herd in heterozygous condition by both of the Shorthorn bulls. Evidence is given for an unusually high frequency of the gene in the stud of origin of the Shorthorn bulls and a procedure for reducing its frequency is outlined. The possibility of a viral or toxic aetiology is discussed but is considered to be an unlikely explanation for the condition in this herd.     

磺胺药和三甲氧苄胺嘧啶在马体内代谢动力学研究

本文以重氮偶合比色法(以下称B-M比色法)或高效液相色谱(以下简称HPLC)法,对磺胺药和三甲氧苄胺嘧啶(TMP)在马体内代谢动力学特征进行了分析。其中磺胺二甲基嘧啶(SM_2)和TMP在血浆中的浓度用HPLC法进行测定。SM_2测定的紫外检测器波长为275nm;流动相为甲醇:去离子水(50:50/V:V)并以36％乙酸将pH调至4.0,流速为0.5ml/min;SM_2的滞留时间为8.05分钟,内标物SMM的滞留时间为9.90分钟。TMP的测定使用紫外检测器,检测波长为254nm;流动相为甲醇:双重蒸馏水:磷酸盐缓冲液(pH7.0):36％乙酸(70:30:1:1),流速为0.8ml/min。SD、SMD、SMM和SDM′的血中浓度用B-M比色法测定。血药浓度—时间数据按多室动力学处理,用Sharp PC-1500袖珍计算机计算数据,所得磺胺药和TMP的动力学参数如下:SD、SM_2、SMD、SMM、SDM′及TMP的t_(1/2)β分别为5.41±1.45、12.92±4.17、5.76±1.22、4.45±1.44、14.13±2.15及4.20±1.08(hr.);表观分布容积(Vd)分别为10.34±1.13、7.95±1.77、4.91±0.46、7.79±0.66、5.69±2.19(100ml/kg)及2.24±0.60(L/kg);曲线下面积(AUC)分别为53.42±14.81、245.14±61.35、84.37±12.73、74.78±18.36、169.74±27.13(mg％·hr.)及41.67±10.40(μg·hr./ml);清除率(Cl_B)分别为1.4476=0.5230、0.431     

SCINTIGRAPHIC EVALUATION OF THE STIFLE IN NORMAL HORSES AND HORSES WITH FORELIMB LAMENESS

We tested the hypotheses that mature horses without lameness have a repeatable radiopharmaceutical uptake pattern in the stifle, which is bilaterally symmetric; immature horses have a different radiopharmaceutical uptake pattern; and forelimb lameness alters the radiopharmaceutical uptake pattern in the stifle. The objectives of the study were to describe the normal radiopharmaceutical uptake patterns using region of interest (ROI) analysis; to compare uptake patterns between left and right stifles of the same horse and between mature and immature horses; to compare radiopharmaceutical uptake in mature normal horses with those with forelimb lameness. Lateral scintigraphic images of the stifle from 51 horses aged 2-16 years were evaluated using seven ROIs and a reference site (midfemur). After subtraction of a background count, ratios between the mean counts per pixel for each ROI to the reference site were calculated. There was a repeatable radiopharmaceutical uptake pattern in mature normal horses that was bilaterally symmetrical. The caudoproximal aspect of the tibia and the patella had the highest ratios. Radiopharmaceutical uptake patterns in horses with forelimb lameness were not significantly different. Immature normal horses had a different symmetric pattern, with greatest radiopharmaceutical uptake ratios in the caudoproximal aspect of the tibia and the tibial crest. It was concluded that there are symmetric, repeatable radiopharmaceutical uptake patterns in both immature and mature horses, which are not altered by forelimb lameness.     

ULTRASONOGRAPHY OF THE FEMORAL ARTERY IN SIX NORMAL HORSES AND THREE HORSES WITH THROMBOSIS

Ultrasonography of the femoral artery in the horse, including color, power and spectral Doppler, provides morphologic and dynamic information. This paper describes the use of the techniques in six clinically normal horses and three with femoral artery thrombosis. Useful landmarks for orientation are the saphenous artery and the medial saphenous vein. The lateral circumflex femoral artery can not be visualized. Recognition of the genus descendens artery is complicated due to the presence of multiple distal caudal femoral arteries. The femoral artery feeds a high resistance bed. In normal horses the peak systolic velocity varies between 50–90 cm/sec. Echoic tissue in the femoral artery lumen with stenosis, occlusion and collateral blood flow formation are features encountered in the patients.     

RADIOLOGIC ANATOMIC VARIATION OF THE CARPUS IN HORSES WITH CARPAL LAMENESS AND CONTROL HORSES

Our purpose was to describe the variation of the radiologic appearance of the carpus of horses of different breeds, discipline, and gender with lameness related to the carpus and control horses, with particular reference to the ulnar carpal bone. Two hundred and eighty‐six sets of carpal radiographs from 222 horses were analyzed. Breed, gender, discipline, and cause of lameness were recorded. Chi square tests were used to test for associations between radiologic findings and gender, breed and discipline, to test for associations between different radiologic findings, and to test for associations between radiologic findings and causes of lameness. Bonferroni correction was applied when necessary. The shape of the ulnar carpal bone and most of the anatomic variants, with the exception of the first carpal bone and a radiolucent area in the second carpal bone, were not breed or gender related. Radiolucent areas and associated fragments on the palmaromedial aspect of the ulnar carpal bone can be an incidental finding in horses from all disciplines.     

CT FEATURES OF ALVEOLITIS AND SINUSITIS IN HORSES

Sinusitis is a common disorder in horses and may result from trauma, dental diseases, or space-occupying lesions. Radiography can only provide a limited amount of information. Computed tomography (CT) has been documented as an alternative imaging method. Eighteen horses (mostly Warmblood) with signs of chronic sinusitis were examined preoperatively with CT to assist in diagnosis of the underlying cause. There was a group of common CT features in horses with dental disease and sinusitis. The first molar was the most frequently affected maxillary cheek tooth. Hypoattenuation of the cementum, destruction of the enamel, and filling of the infundibular cavity with gas were the most frequent CT findings associated with caries. Gas bubbles within the bulging root area or fragmentation of the root in combination with swelling of the adjacent sinus lining were the most important CT features of dental decay. CT findings associated with sinusitis included excessive thickening of the respiratory epithelium in the rostral maxillary sinus; the caudal maxillary sinus was less often involved. The infraorbital canal, the nasomaxillary duct, and the frontomaxillary aperture were usually involved. The maxillary bone, however, especially the facial crest, was involved in nearly every horse, being characterized by endosteal sclerosis, thickening, periosteal reaction, and deformation leading to facial swelling in chronic infections. CT images allowed identification of involvement of individual teeth more clearly to reveal the diseased one for treatment. Three-dimensional imaging allowed improved understanding of the extent and severity of the pathologic change.     

THIAMBUTENE AND ACEPROMAZINE AS ANALGESIC AND PREANESTHETIC AGENTS IN HORSES AND SHEEP

Investigations into the analgesic effect of thiambutene and its value as a pre-anaesthetic agent were carried out in the horse and the sheep. Special emphasis was placed on the post-anaesthetic recovery period.
Thiambutene produced analgesia in both species. Toxic effects such as muscle tremor and hyperkinesia occurred with high doses. Prior administration of acepromazine increased the tolerated doses of thiambutene, and satisfactory neuroleptanalgesic states were produced.
Combined use of thiambutene and acepromazine in pre-anaesthetic medication reduced the dose of thiopentone required for anaesthesia in both species and significantly improved post-anaesthetic recovery.
Administration of nalorphine in both species reduced the duration of the recovery period. In the horse, even after prolonged thiopentone anaesthesia, nalorphine produced a shorter, quieter recovery.
It was concluded that pre-anaesthetic medication with thiambutene and acepromazine facilitated thiopentone anaesthesia and greatly reduced the problems of post-anaesthetic recovery in horses.