Spectral analysis of respiratory noise in horses with upper airway disorders

REASONS FOR PERFORMING STUDY: It has long been recognised that the production of abnormal respiratory sounds by horses during exercise is frequently associated with upper airway obstructions. Respiratory acoustic measurements have shown promise in investigation of upper airway disorders in man and, more recently, in horses with experimentally-induced obstructions. OBJECTIVES: To evaluate sounds from exercising horses with naturally occurring dynamic obstructions of the upper respiratory tract and to compare these with those from normal horses in order to determine whether different obstructions produce characteristic spectral patterns. METHODS: The audio signal, airflow and videoendoscopic images were recorded simultaneously during an incremental exercise test on a high-speed treadmill. RESULTS: Spectral analysis of the audio signal showed marked differences between control and clinically afflicted horses. Dorsal displacement of the soft palate was characterised by a narrow low frequency (20-80 Hz) peak during expiration. Horses with dynamic laryngeal collapse produced inspiratory sounds characterised by a broad band high frequency spectral component in the range 1.1-2.7 kHz. CONCLUSIONS AND POTENTIAL RELEVANCE: Spectral analysis of respiratory sounds in horses has potential as a diagnostic technique for field use especially when facilities for high-speed treadmill assessment are not practicable.     

T-shaped malformation of the ventral colon in a Thoroughbred filly with colic

A 4-month-old Thoroughbred filly presented for abdominal pain was diagnosed with a T-shaped malformation of the ventral colon at exploratory laparotomy. Following resection and anastomosis of the large colon, no further episodes of abdominal pain occurred during a 12-month follow-up. Acute dehiscence of the linea alba occurred as a complication of the initial laparotomy, but was successfully managed following additional surgical repair. T-shaped malformation of the ventral colon has not previously been reported and is considered a congenital malformation of mesocolon formation.     

Failure of passive transfer in foals: incidence and outcome on four studs in New South Wales

Objective To determine the regional incidence and effectiveness of treatment of failure of passive transfer (FPT) in foals. Design A study of disease incidence. Animals Eighty-eight foals and 57 mares from four studs in the practice area of the Rural Veterinary Centre were tested. Procedure Foals were tested for their serum IgG and total serum protein (TSP) concentration within the first 72 hours of life. Colostrum was collected from mares and specific gravity determined. FPT and partial failure of passive transfer (PFPT) of immunoglobulins was diagnosed when serum IgG concentrations were < 4 g/L and 4 to 8 g/L respectively. Owners of foals diagnosed with FPT were offered treatment with 1 to 2 L plasma (TSP > 70 g/L); 9 (64%) of the affected foals were treated. Results Fourteen foals (16%) had FPT whereas 15 (17%) had PFPT. There were significant differences between the mean TSP concentration in foals with FPT (42.6 ± 4.2 g/L), PFPT (48.1 ± 3.9 g/L) and those acquiring adequate passive immunity (58.9 ± 5.5 g/L) (P < 0.01). Sixteen (29%) mares had pre-suck colostral specific gravity < 1.060 and 12 (71%) foals raised by these mares had FPT or PFPT. The incidence of severe disease (categorised by a sepsis score > 11, positive culture of bacteria from blood or disease requiring hospitalisation) in all foals in the first 2 months of life was 10%. However, none of the nine foals with FPT that received plasma experienced severe disease. In contrast, foals with PFPT had an increased susceptibility to severe disease (P < 0.001) when compared with normal foals. Conclusion Treatment of foals with FPT may reduce the subsequent incidence of severe disease. Pre-suck colostral specific gravity and foal TSP may be used to predict the likelihood of FPT and PFPT. Even though the number of foals studied is small the results highlight the importance of optimal management practices in reducing the incidence of FPT and disease associated with this process.     

Immunolocalization of Aquaporins 1 and 9 in the Ram Efferent Ducts and Epididymis

Aquaporins (AQPs) are essential membrane protein channels for the transport of water across membranes. Fluid movement in the epididymis is important for modulation of the luminal environment, in which sperm mature and reside. This study was designed to understand the morphology and localization of AQPs in ram efferent ducts (ED) and epididymis. For this purpose, the epididymis of seven animals were removed for histologic and immunohistochemical analyses. AQP1 immunoreactivity was observed in the apex of the ED, and AQP9 was found adjacent to the nuclei of the epithelial cells of the ED. The epithelial lining of ram epididymis is pseudostratified columnar and presents principal, basal, apical and narrow cells. In the initial segment (IS), a moderate reaction for AQP1 was observed in the apical cytoplasm of epithelial cells. An intense reactivity for AQP1 was noted over the microvilli of principal cells and in spermatozoa in the caput. In the corpus and cauda, AQP1 was noted only over the endothelial cells of vascular channels located in intertubular spaces. A weak‐to‐moderate reaction for AQP9 was observed in the nuclei of epithelial cells in the IS, caput and corpus of the epididymis. In the cauda, an intense reaction to AQP9 was observed in the epithelial border. In the IS, caput and corpus, the reactivity for AQP9 differed from those observed in domestic animals. The cauda showed a pattern similar to that previously described. These results indicate that AQPs 1 and 9 have reversed locations and roles in rams, suggesting activity variations related with fluid and solute absorption throughout the epididymis.     

Unusual osteochondral lesions of the talus in a horse

A 2-year-old Thoroughbred gelding was evaluated for a grade 3 out of 5 unilateral hind limb lameness. Flexion of the right hock and stifle joints (spavin test) exacerbated the lameness. Response to intra-articular and perineural anaesthesia isolated the source of lameness to the tarsocrural area, despite an absence of tarsocrural joint effusion. Routine radiographic examination of the hock did not reveal any significant abnormalities. Skeletal nuclear scintigraphic evaluation revealed a focal region of increased bone activity in the proximal medial trochlear ridge of the talus. Flexed lateromedial radiographic views identified three discrete semicircular lytic lesions at the proximal articular margin of the medial trochlear ridge of the talus. Conservative management of the lesions was associated with a successful return to racing. The location and appearance of the osteochondral lesions of this report have not been previously reported and may be a manifestation of developmental orthopaedic disease and abnormal endochondral ossification. Nuclear scintigraphy and flexed lateromedial radiographic views facilitated identification of the lesions. This radiographic view is recommended when lameness is isolated to the tarsocrural joint and standard radio-graphic projections fail to identify a cause.