不同超排方案以及重复超排对犊牛超排效果的影响

本试验选择北京奶牛中心良种场36头9~12月龄的犊牛进行超排采卵,研究了不同超排方案以及重复超排对犊牛超排的效果。结果表明,超排方案以埋植CIDR的同时,第5天、第6天注射FSH,第7天手术采卵获得的可用卵母细胞数最多。两次重复超排对犊牛平均卵泡数和平均卵母细胞数没有显著影响,但三次超排后的平均卵泡数和平均卵母细胞数显著低于一次和二次超排。     

Cricopharyngeal achalasia in Cocker Spaniels

Cricopharyngeal achalasia is described in three Cocker Spaniel puppies, two being male littermates, the other a bitch from a litter comprising two bitches and two dogs. From 3 weeks of age, solid food was consistently regurgitated, while some fluids were returned via the nares. Diagnosis was made on fluoroscopic demonstration of failure of relaxation of the cricopharyngeal sphincter dorsal to the larynx. Myotomy of the cricopharyngeus muscle and partial section of the thyropharyngeus and oesophageal musculature resulted in considerable improvement. One animal with aspiration pneumonia remained with an occasional cough and all three animals were liable occasionally to regurgitate if eating fast.     

Surgical treatment of perineal hernia in the dog

In a nine-year period 101 dogs which were available for subsequent follow-up studies, were subjected to perineal hernia surgery. In thirty-six dogs the hernia was bilateral and, therefore, 137 hernias were initially operated. In 111 operations the standard perineal technique was adopted. In twenty-six operations the superficial gluteal muscle was reflected and sutured into the hernial defect (‘gluteal flap’). Later, following recurrence of hernia or new development on the second side, a further sixteen operations were done, including three anal splitting procedures. In all cases the deep sutures were of monofilament nylon. A post-operative follow-up was carried out for a minimum period of 12 (average 39) months. The operative and post-operative complications included superficial and deep wound infection, partial or complete sciatic paralysis, rectal prolapse and recurrence of the hernia following breakdown of the repair, as well as occurrence of the hernia on the opposite side. The success rate (75 per cent excluding six immediate post-operative fatalities) judged by remission of signs and lack of recurrence was higher in the standard technique (81 per cent) than the gluteal flap method (64 per cent). Anal splitting was unsuccessful and resulted in faecal incontinence. The standard technique was slow, sometimes gave limited exposure but was rarely associated with wound breakdown (13 per cent of operations), though sciatic paralysis was only noted in this procedure. The gluteal flap method was longer, gave excellent exposure with no risk of sciatic nerve damage, but was often associated with wound breakdown (58 per cent). Both techniques led sometimes to rectal prolapse. Castration with hernial repair resulted in a lower recurrence rate (13 per cent v. 20 per cent). Castration should be carried out in all cases of perineal hernia.     

Radiological diagnosis and prognosis of primary abdominal neoplasia in the dog*

Alimentary and splenic neoplasms formed the largest groups in a series of 121 primary abdominal neoplasms in 117 dogs examined as clinical cases in Glasgow University Veterinary Hospital in the period 1970-74. The majority of the neoplasms were malignant (107 of 121), but few cases had lung metastases. Retrospective study of the radiographs of ninety-one animals in the series was undertaken. Gastro-intestinal lymphosarcoma, which formed the largest single group (thirty-four) was rarely suspected on plain film radiography since gross masses were usually absent and the associated drainage lymph nodes rarely demonstrable. Barium study was useful in delineating gastric malignancy and the occasional unusual small intestinal filling defects which might indicate tumour. Radiography demonstrated the majority of cases of splenic enlargement well, but was of no assistance in the differentiation of benign or malignant lesions. Appropriate contrast studies of the urinary tract were very useful in the investigation of suspected renal, ureteric and bladder neoplasms. Radiographic signs of spinal involvement from spread of abdominal neoplasms was rare, occurring in two cases, once to the seventh lumbar vertebra, once to the first coccygeal vertebra. Radiography rarely demonstrated lung metastases. The prognosis in most cases of abdominal tumours with the exception of splenic neoplasms, is poor. Radiography has marked limitations in the demonstration of many pathological entities of the abdomen including tumours, and contrast studies, though often rewarding, are liable to be very time-consuming. The ultimate diagnosis depends on exploratory laparotomy.     

Muscle perfusion in the horse

Muscle perfusion was studied in conscious and anaesthetised horses by monitoring the clearance of a locally injected bolus of saline containing radioactive xenon (¹³³Xe). The mean of all the measurements made from the brachiocephalicus and semimembranosus muscles in conscious subjects was 1.29 ml/min/100 g while in anaesthetised subjects it was 0.40 ml/min/100 g. The significance of these results is discussed in relation to the clinical occurrence of post anaesthetic myositis.     

Reproductive efficiency of Thoroughbred and Standardbred horses in north-east Victoria

Objective To evaluate the reproductive efficiency of horse farms in north-east Victoria and identify aspects of management to be targeted for improving reproductive efficiency. Design Retrospective study. Procedure Records from seven Thoroughbred (TB) and four Standardbred (STB) studs in north-east Victoria from 1990 to 2001 were reviewed; 8813 cycles in 4455 mares were analysed. TB mares were inseminated by natural mating, whereas STB mares (89%) were artificially inseminated. Results The overall early pregnancy rate per cycle was 68.8% for TB mares and for STB mares, 68.3%. Multiple pregnancy per cycle was more frequent in TB (8.3%) than in STB (4.6%) mares (P < 0.001). Early embryonic death occurred in 7.1% of TB and 7.5% of STB pregnancies. TB mares had fewer inseminations per cycle (1.03) than STB mares (1.43) (P < 0.001). There was a significantly lower proportion of barren reproductive status within the TB than the STB mares. Pregnancy rate per cycle among stallions ranged from 48% to 79%. Conclusions On-farm pregnancy rates in both breeds were higher than previously reported and likely reflect improvements in reproductive management. The disparity between breeds in the inseminations per cycle and proportion of barren mares exposed the differing structures of the two industries, and presents a target for improving the reproductive efficiency in STBs. The difference between breeds in the multiple pregnancy rate per cycle likely reflects the higher ovulation rate of TB mares. The variability in pregnancy rate per cycle between the 22 stallions was associated with differences in individual inherent fertility and the quality of stallion management.     

Trivial Sources of Heterosis in Cotton?

Historically,re-selection,pedigree,and mass selection breeding methods have been used to develop open-pollinated cultivars of Upland cotton (Gossypium hirsutum L.).Due to the predominance of these breeding methods,we hypothesize that modern cultivars,as opposed to obsolete cultivars,have accumulated additive genetic effects over time.     

Imaging electron wave functions of quantized energy levels in carbon nanotubes

Carbon nanotubes provide a unique system for studying one-dimensional quantization phenomena. Scanning tunneling microscopy was used to observe the electronic wave functions that correspond to quantized energy levels in short metallic carbon nanotubes. Discrete electron waves were apparent from periodic oscillations in the differential conductance as a function of the position along the tube axis, with a period that differed from that of the atomic lattice. Wave functions could be observed for several electron states at adjacent discrete energies. The measured wavelengths are in good agreement with the calculated Fermi wavelength for armchair nanotubes.     

Retropharyngeal lymph node infection in horses: 46 cases (1977–1992)

SUMMARY A retrospective study of 46 horses with retropharyngeal lymph node (RPLN) infection presented to the Rural Veterinary Centre between 1977 and 1992 was undertaken. Horses aged less than one year were most commonly represented (46%). Thirty-nine percent of cases had been exposed to horses with confirmed or suspected strangles (Streptococcus equi subsp equi infection) within the previous 8 weeks. Most frequent signs were unilateral or bilateral swelling of the throat region (65%), respiratory stertor/dyspnoea (35%), purulent nasal discharge (20%), inappetence and signs of depression (15%), and dysphagia (9%). All horses had a soft tissue density in the retropharyngeal region on radiographs. Rhinopharyngoscopy, ultrasonography, haematology as well as cytological and microbial analysis of material aspirated from the soft tissue swelling facilitated diagnosis in some horses. Fifteen horses (33%) were treated with procaine penicillin intramuscularly for 4 to 7 days followed by oral trimethoprim-sulphadimidine for 7 to 14 days. Non-steroidal anti-inflammatory drugs were administered to 6 horses. Four required tracheostomy for severe respiratory distress. The 15 horses treated medically responded to treatment and were discharged from hospital. Three horses (6%) with mild signs received no treatment and recovered uneventfully. Twenty-eight horses (61%) underwent general anaesthesia and surgical drainage of a RPLN abscess. Nineteen received procaine penicillin G for 4 to 7 days. Four of the nine horses that did not receive antibiotic treatment after surgery required further surgical drainage 10 days to 7 weeks after the initial surgery . Limited follow-up information was available for 37 horses. Thirty-two horses were considered to have made complete recovery, 3 horses had died through misadventure and 2 had been euthanased because of chronic ill-thrift .