The effects of stock crate design and stocking density on environmental conditions for lambs on road transport vehicles

AIM: The aim of this study was to evaluate the potential of variations in stock crate design (especially ventilation) and stocking density on road transport vehicles for reducing the risk of environmental stress for lambs during long-haul transport in hot weather. METHODS: In Experiment 1, lambs were transported on vehicles fitted with either a newer-design aluminium crate comprising a three-deck truck and four-deck trailer, or an older-design, more open, steel crate of a three-deck truck and three-deck trailer. In Experiment 2, lambs were transported on newer-design vehicles at either standard stocking density (0.20 m2 per 35 kg lamb) or at a 20% lower density (0.26 m2 per 35 kg lamb). In each experiment, each journey was replicated twice and consisted of travel periods and stationary periods designed to emulate conditions associated with an inter-island ferry crossing. Air ammonia concentrations and temperature and humidity were monitored within six pens on each vehicle, and the temperature-humidity index (THI) was calculated. RESULTS: Ammonia concentrations were variable and generally 50 ppm, and did not vary significantly with treatment. The THI increased when the vehicles were stationary, especially under conditions designed to emulate an enclosed ferry deck. The ambient temperature during Experiment 1 was moderate (up to 21 degrees C), and THI was slightly lower in the older-design crate. High ambient temperatures (up to 33 degrees C) were present during Experiment 2, and THI was significantly lower at the lower stock density. During a 3-h stationary period, the peak THI at standard stocking density was 91.0, compared with 84.9 for the low density treatment (p<0.001). CONCLUSIONS: For standard road transport vehicles used for long-haul transport of lambs, lowered loading density may be of considerable benefit in alleviating conditions that increase the risk of lamb deaths during inter-island transport on hot days.     

Single ventricle,total transposition,and hypoplastic aorta in a calf

A purebred Ayrshire calf was born with multiple congenital cardiac defects. The major defects included absence of an interventricular septum (i.e., single ventricle), transposition of the aorta and pulmonary trunk, interatrial septal defect, patent ductus arteriosus, and aortic arch anomalies. Despite the severity of the anomalies, the calf survived to 5 days of age, when it was found dead. This particular combination of cardiac defects has not been previously described in domestic animals.     

In vitro comparison of metaphyseal and diaphyseal placement of centrally threaded, positive-profile transfixation pins in the equine third metacarpal bone

OBJECTIVE: To evaluate in vitro holding power and associated microstructural and thermal damage from placement of positive-profile transfixation pins in the diaphysis and metaphysis of the equine third metacarpal bone. SAMPLE POPULATION: Third metacarpal bones from 30 pairs of adult equine cadavers. PROCEDURE: Centrally threaded positive-profile transfixation pins were placed in the diaphysis of 1 metacarpal bone and the metaphysis of the opposite metacarpal bone of 15 pairs of bones. Tensile force at failure for axial extraction was measured with a materials testing system. An additional 15 pairs of metacarpal bones were tested similarly following cyclic loading. Microstructural damage was evaluated via scanning electron microscopy in another 6 pairs of metacarpal bones, 2 pairs in each of the following 3 groups: metacarpal bones with tapped holes and without transfixation pin placement, metacarpal bones following transfixation pin placement, and metacarpal bones following transfixation pin placement and cyclic loading. Temperature of the hardware was measured with a surface thermocouple in 12 additional metacarpal bones warmed to 38 C. RESULTS: The diaphysis provided significantly greater resistance to axial extraction than the metaphysis. There were no significant temperature differences between diaphyseal and metaphyseal placement. Microstructural damage was limited to occasional microfractures seen only in cortical bone of diaphyseal and metaphyseal locations. Microfractures originated during drilling and tapping but did not worsen following transfixation pin placement or cyclic loading. CONCLUSIONS AND CLINICAL RELEVANCE: Centrally threaded, positive-profile transfixation pins have greater resistance to axial extraction in the diaphysis than in the metaphysis of equine third metacarpal bone in vitro. This information may be used to create more stable external skeletal fixation in horses with fractures.     

Every man his own farrier in Australia: the origins and growth of a veterinary business in colonial New South Wales

The life and work is told of John Pottie (1832-1908), a Scotsman who graduated from Edinburgh Veterinary College in 1858. A year later, he contracted to provide veterinary care to a consignment of horses bound for Australia. Once there, he founded a firm that has survived to the present day, still marketing products that originated in his own veterinary remedies. John Pottie brought with him a European tradition of livestock care and treatment that was epitomised in Clater's title and book, Every man his own farrier. His career is of interest for several reasons. Firstly it is because he used this tradition to launch a business enterprise in a new and different market in Australia. Secondly, although his training lay in what may be termed the pre-scientific era of the profession's history, he was able to adapt old traditions successfully to the changes that came in the age of Pasteur and Koch. Finally, the manner in which he did this, besides demonstrating his business acumen, also shows how the professional veterinary qualification gained in value in a new age of science.     

Exotic mammal renal disease: diagnosis and treatment.

Knowledge of the renal anatomy and clinical pathology associated with renal disease can help the practitioner with interpretation of imaging procedures and urine, blood, and serum biochemical values.This article discusses specimen collection techniques, along with species variables in several clinical pathology parameters. Diagnostic tools and interpretations are discussed for the more common renal maladies affecting exotic mammals. Treatment guidelines are offered for general as well as specific exotic mammal renal diseases.     

Analysis and modeling of gas exchange processes in Scaevola aemula

Scaevola aemula is a popular ornamental crop cultivated as a bedding plant or for hanging baskets. We characterized gas exchange properties of S. aemula ‘New Wonder’ in response to photosynthetically active radiation (PAR), carbon dioxide concentration, and leaf temperature. Net CO₂ assimilation rate (A) was responsive to CO₂, exhibiting a saturation when intercellular CO₂ concentration (C_i) was greater than 600 μmol mol⁻¹. Net CO₂ assimilation rate and dark respiration rate (R_d) were 23.1 and 2.3 μmol m⁻² s⁻¹, respectively, at 25 °C and PAR = 1500 μmol m⁻² s⁻¹. Net CO₂ assimilation rates were similar at leaf temperatures between 20 and 30 °C but significantly reduced at 15 °C. These gas exchange results were used to test the extendibility of a coupled gas exchange model previously developed for cut-roses. Utilizing the gas exchange data measured at 25 °C leaf temperature, several model parameters were independently determined for S. aemula. Model predictions were then compared with observations at different leaf temperatures. The model predicted the rates of net CO₂ assimilation and transpiration of S. aemula reasonably well. Without additional calibration, the model was capable of predicting the temperature dependence of net CO₂ assimilation and transpiration rates. Applying the model to predict the effects of supplemental lighting and CO₂ enrichment on canopy photosynthesis and transpiration rates, we show that this model could be a useful tool for examining environmental control options for S. aemula production in the greenhouse.     

Humoral and cellular immunoresponsiveness of stanchioned cattle infested with Psoroptes ovis

Bovine scabies in a clinical problem during the cool autumn and cold winter months. In south Texas it is necessary to stanchion animals in order to elicit patent infestation during summer months. Environmental factors and grooming have been purported to account for summer resistance to infestation. However, stanchioned animals exhibit varied levels of susceptibility to infestation, suggesting that the noted variability may be influenced by the host immune response. In this study, animals were infested with Psoroptes ovis while in stanchions. The development of anti-P. ovis antibody activity was measured by the enzyme-linked immunosorbent assay and cellular immune function was monitored with mitogens and P. ovis antigens. A correlation was noted between the development of anti-P. ovis antibody activity and the increase in mite numbers and dermatitis. Coincident with the developing infestation was a suppression of T-cell function that appeared to be stress-related as a result of stanchioning. A working hypothesis is presented that attempts to correlate the developing humoral response and the depressed T-cell response with both an increasing dermatitis and mite population.     

Effect of sodium bicarbonate on racing Standardbreds

Twenty-two Standardbred horses in race training were used in a crossover experiment to determine the effect of oral sodium bicarbonate (NaHCO3) administration on performance and metabolic responses to a 1.6-km (1-mile) race. Horses were paired and one horse in each pair was treated with either NaHCO3 (300 mg/kg BW) or a placebo, 2.5 h before they raced against each other. Each horse was scheduled to compete in two races, approximately 1 wk apart, one on each treatment. Horses always raced in the same pairs. Fourteen horses successfully completed both races. Jugular blood samples were obtained 1.5 h after treatment (rest), immediately before racing, 5 min post-race and 15 min post-race. In six horses, blood samples also were obtained 30 min post-race. Race times averaged 1.1 s faster after NaHCO3 treatment (P less than .1). Sodium bicarbonate treatment also elevated blood pH (P less than .05). In the horses sampled 15 and 30 min post-race, blood lactate disappearance was faster with the NaHCO3 treatment (P less than .05). The NaHCO3 may delay the fatigue precipitated by i.m. acidosis. Because other factors may limit performance (musculoskeletal soundness, cardiovascular and respiratory ability), NaHCO3 would not be expected to enhance the performance of all horses. However, the effect of NaHCO3 on lactate clearance may have implications for all intensively worked horses; because lactate and the associated hydrogen ions are believed to cause muscle damage and soreness, any mechanism to increase their removal rate could benefit the equine athlete.