AN APPLICATION OF IMAGE PROCESSING TECHNIQUES IN COMPUTED TOMOGRAPHY IMAGE ANALYSIS

An estimate of the thickness of subcutaneous adipose tissue at differing positions around the body was required in a study examining body composition. To eliminate human error associated with the manual placement of markers for measurements and to facilitate the collection of data from a large number of animals and image slices, automation of the process was desirable. The open-source and free image analysis program ImageJ was used. A macro procedure was created that provided the required functionality. The macro performs a number of basic image processing procedures. These include an initial process designed to remove the scanning table from the image and to center the animal in the image. This is followed by placement of a vertical line segment from the mid point of the upper border of the image to the image center. Measurements are made between automatically detected outer and inner boundaries of subcutaneous adipose tissue along this line segment. This process was repeated as the image was rotated (with the line position remaining unchanged) so that measurements around the complete circumference were obtained. Additionally, an image was created showing all detected boundary points so that sites of measurement could be checked by visual inspection. This paper provides a detailed account of this macro, illustrates the effect of its components on the image, and the applicability of standard image processing techniques to veterinary imaging.     

Effect of previous locoweed (Astragalus and Oxytropis species) intoxication on conditioned taste aversions in horses and sheep

Locoweed species (Astragalus and Oxytropis spp.) are a serious toxic plant problem for grazing livestock. Horses and sheep have been conditioned to avoid eating locoweed using the aversive agent LiCl. The objective of this study was to determine if previous locoweed intoxication affects food aversion learning in horses and sheep. Horses and sheep were divided into 3 treatment groups: control (not fed locoweed and not averted to a novel feed); locoweed-novel feed averted (fed locoweed and averted to a novel feed); and averted (not fed locoweed and averted to a novel feed). Animals in the locoweed-novel feed averted groups were fed locoweed during 2 periods of 21 and 14 d, respectively, with each feeding period followed by a 14-d recovery period. Animals were averted to a novel test feed at the end of the first locoweed-feeding period, and periodically evaluated for the strength and persistence of the aversion. During the first recovery period, locoweed-novel feed averted horses ate less (9.5% of amount offered) of the test feed than did control horses (99.8%) and did not generally differ from averted horses (0%). During recovery period 2, locoweed-novel feed averted horses (4.3%) differed (P = 0.001) in consumption (% of offered) of the test feed from controls (100%) and the averted group (0%). Locoweed-novel feed averted sheep differed (P = 0.001) from controls (14.4 vs. 99.5%, respectively, during recovery period 1), whereas locoweed-novel feed averted sheep did not differ (P > 0.50) from averted sheep (0.6%). During the second recovery period, control sheep (100%) differed (P < 0.05) from averted (0%) and locoweed-novel feed averted (12.2%) groups. Two intoxicated sheep (locoweed-novel feed averted) partially extinguished the aversion during the first recovery period, but an additional dose of LiCl restored the aversion. Two of 3 intoxicated horses had strong aversions that persisted without extinction; 1 horse in the locoweed-novel feed averted group had a weaker aversion. These findings suggest that horses and sheep previously intoxicated by locoweeds can form strong and persistent aversions to a novel feed, but in some animals, those aversions may not be as strong as in animals that were never intoxicated.     

Effect of system of feeding and watering on performance of lactating sows

An experiment was conducted to determine the effects of ad libitum access to feed and water and the option to mix feed and water, all in the same feeder, on the performance of multiparous lactating sows. Feed and water were made available to sows using a self-fed wet/dry (SFWD) or a hand-fed (HF) feed-water system. In the SFWD system, feed and water were dropped into a common trough area of the feeder. The sow determined when and how much of each was dropped. With feed falling onto the flat area of the bottom of the SFWD feeder trough and water falling into the shallow bowl area, and with the 2 areas seamlessly connected, the sow also determined the wetness of the feed consumed. In the HF system, sows were given dry feed twice daily in a J-shaped feeder that was independent of the sow's water source. Sows (n = 114) were assigned to treatments based on parity and genotype. Total feed disappearance per sow during lactation (20 +/- 0.2 d) was greater (P < 0.01) with the SFWD system than with the HF system (120 vs. 110 +/- 4.1 kg, respectively). The SFWD sows had greater (P < 0.01) BW gains during lactation than HF sows (6.2 vs. 0.6 +/- 1.85 kg, respectively). Backfat depth change during lactation did not differ (P = 0.37) between treatments. Likewise, percentage of sows displaying estrus by d 11 post-weaning did not differ (P = 0.51). Piglet weaning BW was greater (P < 0.01) with the SFWD system than with the HF system (6.63 vs. 6.12 +/- 0.22 kg, respectively). Sow average daily water intake and total feed wastage during lactation did not differ (P > 0.66) between treatments. However, sows with the SFWD system wasted less water (P < 0.01) than those with the HF system (15 vs. 232 +/- 12 L, respectively). From a commercial swine production perspective, the difference in waste water volume would result in a significant variation in costs associated with manure storage and distribution. In conclusion, use of a SFWD feed-water system in lactation, which provides sows choices of when to eat, how much to eat, and if dry feed should be mixed with water during consumption, enhances sow appetite, improves litter growth performance, and wastes less water than a HF feed-water system.     

A packed-bed filtration system for collection of Myxobolus cerebralis triactinomyxons

Information on the distribution and abundance of Myxobolus cerebralis triactinomyxons in natural systems is limited because direct and accurate sampling methods for this life stage have not been developed. Existing methods are based on indirect measures of triactinomyxon densities and are therefore confounded. Direct estimation of triactinomyxon concentrations would more exactly pinpoint the ambient infection risk to wild fish and allow evaluation of management strategies designed to mitigate the effects of the disease. We developed a mobile packed-bed filtration system that quickly, accurately, and precisely collects, concentrates, and quantifies triactinomyxons. The system includes pumping, prefiltration, two rounds of packed-bed filtration, and centrifugation. Laboratory tests of the completed system using known quantities of triactinomyxons resulted in a mean recovery rate of 91% with a minimum detectable concentration of triactinomyxons of 0.04/L. We subsequently field-tested the system at a site known to be positive for the parasite and recovered triactinomyxons at densities of 0.7-1.4/L. The packed-bed filtration system has the potential to quickly determine the temporal and spatial variation in infection risk and to test the efficacy of various management strategies.     

Effect of feeding fermented liquid feed and fermented grain on gastrointestinal ecology and growth performance in piglets

To investigate the microbial and nutritional characteristics of dry feed, liquid feed containing fermented liquid cereal grains, and fermented liquid feed, and their effect on gastrointestinal ecology and growth performance, 120 piglets from 40 litters were used and housed in pens with 5 animals in each. The 3 dietary treatments (all nonheated and nonpelleted diets) were: a dry meal diet (DRY); a fermented, liquid cereal grain feed (FLG); and a fermented liquid feed (FLF). The FLG diet was prepared by storing the dietary cereals (barley and wheat) and water (1:2.5, wt/wt) in a closed tank at 20 degrees C and adding the remaining dietary ingredients immediately before feeding. The FLF diet was prepared by storing compound feed and water (1:2.5, wt/wt) in a closed tank at 20 degrees C. Three times daily, 50% of the fermented cereals or compound feed and water stored in the tanks was removed and replaced with an equal amount of fresh cereals or feed and water. On d 14, 1 piglet from each pen was killed and samples from the gastrointestinal tract were obtained. The pH of the fermented cereals was 3.85 (SD = 0.10), that of the FLG diet was 5.00 (SD = 0.18), and the pH of the FLF diet was 4.45 (SD = 0.11). The dietary concentration of lysine (g/16 g of N) pointed to a decreased concentration in the FLF (5.46, SD = 0.08) compared with the DRY (6.01) and FLG (6.21, SD = 0.27) diets, and the concentration of cadaverine was greater in the FLF diet (890 mg/kg, SD = 151.3) than in the DRY (32 mg/kg) or FLG (153 mg/kg, SD = 18.7) diets. Fermenting only the cereal component of the diet (FLG) promoted the growth of yeasts to a greater extent than fermenting the whole diet (FLF). Terminal RFLP profiles of diets and digesta from the stomach and midcolon showed differences among dietary groups. The number of yeasts able to grow at 37 degrees C in the stomach and caudal small intestine was greatest in the FLG group compared with the other 2 dietary groups (P < 0.01). In the cecum and colon, the differences were only significant between piglets fed the FLG and the FLF diets (P < 0.05). The greatest number of yeasts able to grow at 20 degrees C was detected in the animals fed the FLG diet. However, the values were different from the FLF-fed piglets only in the stomach (P < 0.05) and midcolon (P < 0.05). There was a tendency (P < 0.10) for greater ADG of the piglets fed the FLG compared with the FLF diet. Feeding liquid feed containing fermented, liquid cereal grains as a means of avoiding microbial decarboxylation of free amino acids in the feed and increasing feed intake by improving palatability seems promising but requires further investigation.     

Biofilms and their relevance to veterinary medicine

Bacteria are renowned for their ability to tolerate and adapt to a wide range of adverse environmental conditions. The primary mechanism that facilitates these adaptations is thought to be the capacity to form and maintain biofilms. Within a biofilm, bacteria become attached to a surface where they exist in complex communities which are able to interact with each other through intracellular communication and thus rapidly adapt to changing environments. The organisms within biofilms are notorious for their resistance towards the host immune response and antibacterial agents compared to their free-living planktonic counterparts. Consequently, biofilms are of significant importance to both clinical and veterinary science. However, although bacterial infections are widely reported in animals their association with biofilms is rarely discussed. The aim of this review is to look at the characteristics of biofilm infections in humans and to relate this knowledge to veterinary science in order to assess their relevance in this area.     

Diagnostic procedures and surgical treatment of craniodorsal coxofemoral luxation in calves

OBJECTIVE: To report use of ultrasonographic examination of the coxofemoral joint, a surgical technique for repair of craniodorsal coxofemoral dislocation, and outcome. STUDY DESIGN: Clinical case reports. ANIMALS: Calves (n=4) with coxofemoral luxation. METHODS: Craniodorsal coxofemoral luxation was diagnosed by physical examination, radiographic, and ultrasonographic findings. Open surgical reduction of the femoral head was performed using a modified caudal approach. RESULTS: Craniodorsal luxation of the femoral head and the presence of an intact femoral neck were confirmed by ultrasonography. All luxations were successfully reduced and reluxation did not occur. At follow-up, 1 heifer had calved and 1 was 5 months pregnant. One calf died of bronchopneumonia 6 days after surgery. One calf had severe coxofemoral degenerative joint disease diagnosed (ultrasonography, radiography, and arthrocentesis) 3 months after surgery and confirmed by necropsy. CONCLUSION: Ultrasonography proved to be a simple and effective non-invasive technique for diagnosis of coxofemoral luxation. Immediate surgical intervention in hip dislocation in calves is necessary to avoid unnecessary trauma to subchondral structures. In calves, open instead of closed surgical reduction appears preferable because it allows access to the acetabular cavity for removal of debris. CLINICAL RELEVANCE: Ultrasonography should be considered a supplementary but not an alternative to radiographic examination for diagnosis of coxofemoral luxation and for follow-up examinations after reduction.     

Breed associations for canine exocrine pancreatic insufficiency

BACKGROUND: Knowledge of breed associations is valuable to clinicians and researchers investigating diseases with a genetic basis. HYPOTHESIS: Among symptomatic dogs tested for exocrine pancreatic insufficiency (EPI) by canine trypsin-like immunoreactivity (cTLI) assay, EPI is common in certain breeds and rare in others. Some breeds may be overrepresented or underrepresented in the population of dogs with EPI. Pathogenesis of EPI may be different among breeds. ANIMALS: Client-owned dogs with clinical signs, tested for EPI by radioimmunoassay of serum cTLI, were used. METHODS: In this retrospective study, results of 13,069 cTLI assays were reviewed. RESULTS: An association with EPI was found in Chows, Cavalier King Charles Spaniels (CKCS), Rough-Coated Collies (RCC), and German Shepherd Dogs (GSD) (all P < .001). Chows (median, 16 months) were younger at diagnosis than CKCS (median, 72 months, P < .001), but not significantly different from GSD (median, 36 months, P = .10) or RCC (median, 36 months, P = .16). GSD (P < .001) and RCC (P = .015) were younger at diagnosis than CKCS. Boxers (P < .001), Golden Retrievers (P < .001), Labrador Retrievers (P < .001), Rottweilers (P = .022), and Weimaraners (P = .002) were underrepresented in the population with EPI. CONCLUSIONS AND CLINICAL IMPLICATIONS: An association with EPI in Chows has not previously been reported. In breeds with early-onset EPI, immune-mediated mechanisms are possible or the disease may be congenital. When EPI manifests later, as in CKCS, pathogenesis is likely different (eg, secondary to chronic pancreatitis). Underrepresentation of certain breeds among dogs with EPI has not previously been recognized and may imply the existence of breed-specific mechanisms that protect pancreatic tissue from injury.     

Changes in plasma renin activity and renal immunohistochemically demonstrated renin in carbadox treated pigs

Carbadox is known to induce toxic effects on the adrenal cortex, resulting in hypoaldosteronism. To study the involvement of carbadox on the renin-angiotensin system, weaned piglets of five weeks old received feed supplemented with 0 (control group), 50, 100, 150 or 200 ppm carbadox. After four weeks the 100 and 150 ppm groups had significantly higher plasma renin activity levels than the control group and after nine weeks plasma renin activity levels of all treated groups were significantly higher than the control group. Five and 10 weeks after carbadox administration, three and two pigs, respectively, of all groups were necropsied and the kidneys were screened for immunohistochemically demonstrated renin. All dosed pigs demonstrated an increase of immunoreactive renin, which was dose- and time-related. From these results it is concluded that carbadox induces activation of the renin-angiotensin system, secondary to the suppressing effect on mineralocorticoid secretion and that these changes may be responsible for part of the clinical picture.     

Etiologic studies on late-term swine abortions

One hundred thirty-eight swine abortions were studied in detail in an effort to identify an etiologic agent. A viral agent was implicated in 7 cases. Bacteria were isolated in less than half of the examined cases: however, in 61% of the cases, motile, filamentous organisms were observed in tissues and fluids. Although swine sera from farms experiencing reproductive problems had a high reactor rate to Leptospira bratislava antigen, electron microscopy of the observed organism revealed a wall-free prokaryote morphologically typical of the class Mollicutes.