BACKGROUND:Increased D-lactate concentrations cause neurological signs in humans with gastrointestinal disease.HYPOTHESIS/OBJECTIVES:To determine if serum D-lactate concentrations are increased in cats with gastrointestinal disease compared to healthy controls, and if concentrations correlate with specific neurological or gastrointestinal abnormalities.ANIMALS:Systematically selected serum samples submitted to the Gastrointestinal Laboratory at Texas A&M University from 100 cats with clinical signs of gastrointestinal disease and abnormal gastrointestinal function tests, and 30 healthy cats.METHODS:Case-control study in which serum D- and L-lactate concentrations and retrospective data on clinical signs were compared between 30 healthy cats and 100 cats with gastrointestinal disease. Association of D-lactate concentration with tests of GI dysfunction and neurological signs was evaluated by multivariate linear and logistic regression analyses, respectively.RESULTS:All 100 cats had a history of abnormal gastrointestinal signs and abnormal gastrointestinal function test results. Thirty-one cats had definitive or subjective neurological abnormalities. D-lactate concentrations of cats with gastrointestinal disease (median 0.36, range 0.04-8.33 mmol/L) were significantly higher than those in healthy controls (median 0.22, range 0.04-0.87 mmol/L; P = .022). L-lactate concentrations were not significantly different between the 2 groups of cats with gastrointestinal disease and healthy controls. D-lactate concentrations were not significantly associated with fPLI, fTLI, cobalamin, folate, or neurological abnormalities (P > .05).CONCLUSIONS AND CLINICAL IMPORTANCE:D-lactate concentrations can be increased in cats with gastrointestinal disease. These findings warrant additional investigations into the role of intestinal microbiota derangements in cats with gastrointestinal disease, and the association of D-lactate and neurological abnormalities.

The real and/or perceived shortage of veterinarians serving food-supply veterinary medicine has been a topic of considerable discussion for decades. Regardless of this debate, there are issues still facing colleges of veterinary medicine (CVMs) about the best process of educating future food-supply veterinarians. Over the past several years, there have been increasing concerns by some that the needs of food-supply veterinary medicine have not adequately been met through veterinary educational institutions. The food-supply veterinary medical curriculum offered by individual CVMs varies depending on individual curricular design, available resident animal population, available food-animal caseload, faculty, and individual teaching efforts of faculty. All of the institutional members of the Association of American Veterinary Medical Colleges (AAVMC) were requested to share their Food Animal Veterinary Career Incentives Programs. The AAVMC asked all member institutions what incentives they used to attract and educate students interested in, or possibly considering, a career in food-supply veterinary medicine (FSVM). The problem arises as to how we continue to educate veterinary students with ever shrinking budgets and how to recruit and retain faculty with expertise to address the needs of society. Several CVMs use innovative training initiatives to help build successful FSVM programs. This article focuses on dairy, beef, and swine food-animal education and does not characterize colleges educational efforts in poultry and aquaculture. This review highlights the individual strategies used by the CVMs in the United States.

In a crossover study, 5 calves were made acidotic by intermittent intravenous infusion of isotonic hydrochloric acid (HCl) over approximately 24 h. This was followed by rapid (4 h) or slow (24 h) correction of blood pH with isotonic sodium bicarbonate (NaHCO(3)) to determine if rapid correction of acidemia produced paradoxical cerebrospinal fluid (CSF) acidosis. Infusion of HCl produced a marked metabolic acidosis with respiratory compensation. Venous blood pH (mean ± S(x)) was 7.362 ± 0.021 and 7.116 ± 0.032, partial pressure of carbon dioxide (Pco(2), torr) 48.8 ± 1.3 and 34.8 ± 1.4, and bicarbonate (mmol/L), 27.2 ± 1.27 and 11 ± 0.96; CSF pH was 7.344 ± 0.031 and 7.240 ± 0.039, Pco(2) 42.8 ± 2.9 and 34.5 ± 1.4, and bicarbonate 23.5 ± 0.91 and 14.2 ± 1.09 for the period before the infusion of hydrochloric acid and immediately before the start of sodium bicarbonate correction, respectively. In calves treated with rapid infusion of sodium bicarbonate, correction of venous acidemia was significantly more rapid and increases in Pco(2) and bicarbonate in CSF were also more rapid. However, there was no significant difference in CSF pH. After 4 h of correction, CSF pH was 7.238 ± 0.040 and 7.256 ± 0.050, Pco(2) 44.4 ± 2.2 and 34.2 ± 2.1, and bicarbonate 17.8 ± 1.02 and 14.6 ± 1.4 for rapid and slow correction, respectively. Under the conditions of this experiment, rapid correction of acidemia did not provoke paradoxical CSF acidosis.

Rectal temperature measurement is an essential part of physical examination of cattle and some physiological experiments. Modern digital thermometers are often used to measure rectal temperatures by students; this study describes their reliability and appropriate use. Students measured rectal temperature on 53 occasions using their personal digital thermometer and techniques gained from previous instruction, rectal temperature was also measured by an experienced person using a Cornell mercury thermometer completely inserted in the rectum. Cornell mercury thermometers values were 38.95±0.05°C (mean±1 SE, n=53). Student rectal temperature measurements using their initial technique were nearly 0.5°C lower, 38.46±0.07°C. After receiving instruction to insert the digital thermometer to the window, student obtained values were 38.77±0.06°C; these are significantly higher than with the student’s initial technique and closer to those obtained with a Cornell thermometer. In a series of 53 water bath tests, student owned thermometers recorded similar mean values to those of a traceable (reference) digital thermometer, Cornell mercury thermometer readings were 0.2°C higher. 10 individual digital thermometers were repeatedly tested against a traceable thermometer in a water bath, one was inaccurate. In a separate experiment a trained clinician tested the effect of angle of insertion of a digital thermometer on temperature readings and the affect was <0.1°C. We conclude that accurate temperature measurements using digital thermometers are only likely if the thermometer is inserted to the beginning of the window and the thermometer’s accuracy is checked periodically.

The objective of this study was to generate demographic data on veterinarians working in western Canada. A sample of 551 veterinarians was randomly selected from a population of 2474 veterinarians employed in western Canada, 425 (77.1%) of whom responded to the survey. The respondents were evenly split between males (53.1%) and females (46.9%). More than half (58.0%) of the private practitioners practised exclusively on companion animals (small animals and horses), while 2.9% devoted 100% of their time to food animals. There were 351 respondents who had had > or = 2 employers since graduation; 80% of those who had begun their careers in companion animal (CA) practice had remained in this type of practice, while 54.3% of those who had begun their careers in mixed animal practice had switched to CA practice. Analyses of wage and workload data from 85 full-time veterinary employees showed that CA practitioners worked the fewest hours/week (47.0), had the least number of evenings on-call/month (3.7), and earned the highest hourly wage (35.79 dollars) as compared with non-CA practitioners.

We have documented D‐lactic acidosis secondary to diarrhea in neonatal calves and lambs. The acidosis only appears after sufficiently high levels of D‐lactate are produced by microbial action in the gut. Measurements of serum and fecal lactate led to a determination of a fecal threshold for D‐lactate systemic absorption from the gut in neonatal ruminants. Jugular blood and feces were collected from 27 diarrheic and 4 healthy lambs, and 19 diarrheic and 4 healthy calves. Blood was analysed for pH, bicarbonate concentration (HCO3−), base excess (BE), hemoglobin (Hb), Na+, K+, Ca2+, Cl−, anion gap, and glucose. Serum, feces, and urine were analyzed for lactate enantiomers. A range of mild to severe diarrhea, as well as metabolic acidosis was observed with a corresponding wide range of D‐lactate concentrations in both serum (< 0.05‐24.0 mmol/L) and feces (< 0.05‐31.0 mmol/L). The fecal D‐lactate threshold was determined statistically using biphasic (break‐point) regression analysis (serum vs fecal D‐lactate). This fecal threshold concentration for absorption of D‐lactate was 10.2 and 8.8 mmol/L in lambs (n=31) and calves (n=23), respectively. These similar values in different species support a lumen D‐lactate threshold (~10 mmol/L) for monocarboxylic (i.e. lactate) transporters and uptake into the mucosal cells and then blood circulation. Therefore, controlling the amount of D‐lactate produced by gut bacteria, and hence lowering levels below threshold, may be key in preventing the metabolic acidosis common in enteritis.

This second of 2 articles, relating to the veterinary profession in western Canada, explores the factors associated with veterinarians' career path choices. Among other factors, companion animal (small animal and equine) (CA) practitioners were less likely to have been raised in, or near to, a small center (< or = 10 000), were more concerned with their workload (hours of work and number of nights on-call), and preferred to work in progressive practices. Food animal (FA) practitioners were more likely to be male, have been raised in a small center, have been raised in the Province of Saskatchewan, and to have self-assessed themselves as having an above average knowledge of agriculture at the time they applied for admission to veterinary college. Mixed animal (MA) practitioners had more factors in common with FA than with CA practitioners. Three main factors were associated with leaving mixed or food animal practice: hours of work and too many nights on-call, the level of remuneration, and lack of support and mentorship.

This chapter discusses contemporary global challenges facing veterinary educators and summarizes some of the economic, social, political, and technological pressures underlying curricular and pedagogical change initiatives. Integrating human computer interaction (HCI) into veterinary medicine curricula, as a strategy for implementing pedagogical transformation, is reviewed. Computer- assisted learning (CAL) projects recently developed at a veterinary college are described. Results of studies evaluating the effectiveness of CAL approaches to HCI integration within the veterinary medicine curricula are reported. Future research directions are proposed.

D‐lactic acidosis occurs as a complication of short‐bowel syndrome in humans and in a variety of other gastrointestinal disorders in monogastrics and ruminants. It is associated with signs of impaired central nervous system (CNS) function including ataxia and coma. The objective of this experiment was to determine if either acidification of nervous tissue or D‐lactic acid is responsible for decreased neurological function. Eight Holstein calves (32 ± 11 d) were surgically catheterized with indwelling intravenous jugular and atlanto‐occipital space cerebrospinal fluid (CSF) catheters and infused for 6 h in random order with iso‐molar DL‐lactic acid (DL‐LA), L‐lactic acid (L‐LA), hydrochloric acid (HCl) or saline. DL‐LA induced ataxia after 4 h of infusion and produced the greatest obtunding of CNS function (at 7 h, score 8.0 ± 0.4), whereas, the other infusions caused neither ataxia nor scores over 1.5 (p < 0.01 from DL‐LA). After 6 h, DL‐LA induced significantly less acidemia than HCl (pH 7.13 ± 0.06 and 7.00 ± 0.04, base excess −16 ± 1 and −23 ± 3 mmol/l, bicarbonate 11 ± 1 and 8 ± 1 mmol/L respectively, all p < 0.01), but greater than L‐LA and saline (p < 0.01). CSF changes followed a similar but less pronounced pattern. Although HCl infusion produced a severe acidemia and CSF acidosis, only minor effects on neurological function were evident suggesting that D‐lactate has a direct neurotoxic effect that is independent of acidosis. Conversely, L‐LA produced only minor neurological changes.

The objective of this study was to describe the demographics of the Class of 2006, Western College of Veterinary Medicine, and to determine which factors influenced the graduates' career path choices. Data were collected via an on-line survey and the response rate was 95.7% (67/70). The majority (57%) of graduates were starting their veterinary career in a food animal-related (FAR) job. Two factors were significantly associated with this choice: 1) those raised in, or near, a small center (population < 10 000) were 3.4 times (P = 0.03) more likely to accept a FAR position than were those raised in a large center (> 10 000), and 2) graduates with a bachelor of science in agriculture (BSc Ag) were 4.5 times (P = 0.04) more likely to begin their career as a FAR practitioner than were those without such a degree. However, 9 of the 16 graduates having a BSc Ag had an urban upbringing.

D‐lactic acidosis is recognized as a complication of gastrointestinal diseases in humans and ruminants. Absorbed D‐lactate can be excreted via the kidney; however, competition between D‐ and L‐lactate in the renal mechanisms may effect its elimination. The objective of this study was to measure D‐ and L‐lactate clearance in a calf infusion model. Five calves (age 14–31 days, weight 59 ± 8 kg) were infused with DL‐ and L‐lactic acid (300 mmol/L, 2 mL/kg/h for 8 hours) in a randomized cross‐over design. Calves were fitted with intravenous catheters for infusion and blood collection, and with suprapubic bladder catheters for urine collection. Samples for blood gas analysis, serum and urine D‐ and L‐lactate concentration, urine volume and serum and urine creatinine were collected every 2 hours for 24 hours. D‐ and L‐lactate clearances were calculated for each 2 hour interval and compared to creatinine clearance. With infusion of DL‐lactate, average serum D‐lactate concentration at steady state was 2.9 ± 1.6 mmol/L (range 1.8–5.7 mmol/L), and average urine D‐lactate concentration was 4.0 ± 1.7 mmol/L. Average D‐lactate clearance during steady state was 7.4 ± 3.4 mL/min. Percent excretion of infused D‐lactate increased during the 8 hour infusion, with minimum and maximum excretion averaging 0.6 ± 0.1% and 10.4 ± 4.4%. L‐lactate clearance could not be calculated, likely due to rapid metabolism of infused L‐lactate. Therefore, L‐lactate elimination is more efficient than D‐lactate since it can both be metabolized and excreted from the body. (Supported by NSERC Canada)

-Lactic acidosis (DAC) occurs as a complication of short-bowel syndrome in humans and in a variety of other gastrointestinal disorders in monogastrics and ruminants. DAC is associated with signs of impaired central nervous system (CNS) function including ataxia and coma. The objective of this experiment was to determine whether either acidification of nervous tissue or d-lactic acid is responsible for decreased neurological function. Eight Holstein calves (32 ± 11 days, 70 ± 10 kg) were surgically catheterized with indwelling intravenous jugular and atlanto-occipital space cerebrospinal fluid (CSF) catheters and infused for 6 h in random order with isomolar dl-lactic acid (dl-LA), l-lactic acid (l-LA), hydrochloric acid (HCl), or saline. dl-LA induced ataxia after 4 h of infusion and produced the greatest obtunding of CNS function (at 7 h, score 8.0 ± 0.4), whereas the other infusions caused neither ataxia nor scores over 1.5 ( P < 0.01 from dl-LA). dl-LA induced significantly less acidemia than HCl (at 6 h pH 7.13 ± 0.06 and 7.00 ± 0.04, base excess −16 ± 1 and −23 ± 3 mmol/l, bicarbonate 11 ± 1 and 8 ± 1 mmol/l respectively, all P < 0.01) but greater than l-LA and saline ( P < 0.01). CSF changes followed a similar but less pronounced pattern. Although HCl infusion produced a severe acidemia and CSF acidosis, only minor effects on neurological function were evident suggesting that d-lactate has a direct neurotoxic effect that is independent of acidosis. Conversely, l-LA produced only minor neurological changes.

Acidosis despite its origin is treated by quick correction of blood pH via bicarbonate infusion (NaHCO3). However, NaHCO3 treatment can worsen the acidotic condition in the cerebral spinal fluid (CSF). The objective was to determine the effect of rapid versus slow NaHCO3 rates on paradoxical CSF acidosis in experimentally induced acidosis via DL-lactic acid (DL-LA) or hydrochloric acid (HCl). Nine calves (63±4kg, 27±5d) with atlanto-occipital CSF, ear arterial and jugular venous catheters were infused with DL-LA or HCl until severely acidotic (>12h). Acidotic calves were then treated with NaHCO3 for 4h (rapid) or 24h (slow). Blood and CSF were collected at pre, post acidotic and during NaHCO3 therapy, and assessed for acidotic state. Calves were also evaluated for neurological disturbances (ND). HCl and DL-LA induced acidosis responded to NaHCO3 (rapid & slow) with 54% pH recovery at 8h of treatment; however, paradoxical CSF was apparent during the first 4h in 3 groups (pH 7.23±0.09 or >15% drop at 2h) but not for DL-LA (rapid). NaHCO3 (rapid) increased CSF pCO2 to 46±2 mmHg (p<0.05) with >75% recovery by 4h. NaHCO3 was also effective in correcting CSF HCO3− (45%) in all except HCl (slow) group (10%) by 8h. Severe ND were present in DL-LA induced acidosis, but not HCl (p<0.05), and these ND persisted during NaHCO3 therapies. Overall NaHCO3 regimens were clinically safe; however, they did not relieve ND caused by DL-LA. Other treatments especially targeting the origin of acidosis need investigation. (Supported by NSERC Canada)

Lactic acidosis (DAC) occurs as a complication of short-bowel syndrome in humans and in a variety of other gastrointestinal disorders in monogastrics and ruminants. DAC is associated with signs of impaired central nervous system (CNS) function including ataxia and coma. The objective of this experiment was to determine whether either acidification of nervous tissue or d-lactic acid is responsible for decreased neurological function. Eight Holstein calves (32 +/- 11 days, 70 +/- 10 kg) were surgically catheterized with indwelling intravenous jugular and atlanto-occipital space cerebrospinal fluid (CSF) catheters and infused for 6 h in random order with isomolar dl-lactic acid (dl-LA), l-lactic acid (l-LA), hydrochloric acid (HCl), or saline. dl-LA induced ataxia after 4 h of infusion and produced the greatest obtunding of CNS function (at 7 h, score 8.0 +/- 0.4), whereas the other infusions caused neither ataxia nor scores over 1.5 (P < 0.01 from dl-LA). dl-LA induced significantly less acidemia than HCl (at 6 h pH 7.13 +/- 0.06 and 7.00 +/- 0.04, base excess -16 +/- 1 and -23 +/- 3 mmol/l, bicarbonate 11 +/- 1 and 8 +/- 1 mmol/l respectively, all P < 0.01) but greater than l-LA and saline (P < 0.01). CSF changes followed a similar but less pronounced pattern. Although HCl infusion produced a severe acidemia and CSF acidosis, only minor effects on neurological function were evident suggesting that d-lactate has a direct neurotoxic effect that is independent of acidosis. Conversely, l-LA produced only minor neurological changes.

Fluid therapy is a critically important aspect of supportive care for horses with a variety of medical and surgical disorders. With the development of systems facilitating administration of large volumes of intravenous fluids, intravenous fluid therapy has become a standard treatment in equine veterinary hospitals. This primer was written to help students, technicians, and equine veterinarians develop a basic working knowledge of fluid and electrolyte balance, understand the losses accompanying disorders leading to dehydration, and learn the approach to fluid therapy. It is not meant to be a detailed review of the literature, and therefore supporting references are not provided.

The effect of changes in feed intake on auscultatable gastrointestinal sounds has not been systematically studied. Disagreement also is present in the literature about variation in sounds according to the quadrant of auscultation. Gastrointestinal sounds were recorded over the center of the left dorsal, left ventral, right ventral, and right dorsal quadrants and over the middle of the right abdominal flank. During 24 hours (n = 4) or 48 hours (n = 5) of fasting, there was a reduction in the intensity of gastrointestinal sounds as assessed by analysis of sound recordings. There was also a reduction in the number of mixing-like and propulsive-like sounds heard by 2 blinded observers. After refeeding, there was a marked increase in sound. Sound intensity varied among abdominal quadrants, but blinded observers did not notice significant differences in the number of mixing-like sounds. The left dorsal quadrant was quieter than others during fasting and refeeding. The right ventral quadrant appeared to be least affected by fasting, and sounds were louder over the right ventral and right middle quadrants than over the others. The blinded observers' perceptions of sound correlated poorly with one another and with objective measures of sound intensity. This experiment demonstrates the effectiveness of computerized analysis of abdominal sound in detecting a reduction in the intensity of gastrointestinal sounds during fasting and their return during refeeding. The left dorsal quadrant was quieter than other quadrants, likely because of its position over the small colon. There was considerable observer variation in the number of intestinal sounds heard.

OBJECTIVE:To evaluate the effectiveness of a self-learning computer module (SLCM) versus traditional instruction in teaching how to pass a nasogastric tube (NG) in the horse.DESIGN:A double-blind, monocentric study.SAMPLE POPULATION:52 third-year students in the DVM program were randomly assigned to two groups: traditional instruction (N = 25) or SLCM instruction (N = 27).PROCEDURE:Traditional instruction consisted of an instructor and live demonstration; SCLM students were given a CD-ROM each. Both sessions lasted one hour. The students were then united in one session to practice passing the NG tube. Their performance was videotaped and evaluated by two evaluators. Students were then given a multiple-choice knowledge quiz. One week later, a second demonstration of the same procedure by the two methods was administered, and students were allowed to choose either method of instruction. A Likert-scale questionnaire about their comfort, their confidence, and the appropriateness of the teaching method was given after the second demonstration. Data were analyzed by non-parametric tests. A focus-group study was conducted to determine students' perception of each teaching method. Nine participants in the experiment volunteered for these focus-group sessions. The sessions were audiotaped and transcribed.RESULTS:Students in the SLCM group performed significantly better on the test of knowledge than traditionally instructed students. The questionnaire found significant perceived benefits to computer-based instruction, including a preference for the computer-based module, better learning, and greater preparedness. In hands-on skill, time to pass the NG tube on the successful attempt was significantly shorter in the SLCM group than in the traditionally instructed group. The data from focus-group sessions suggest that while participants expressed satisfaction with both modes of instruction, the SLCM group reported somewhat higher levels of confidence in their skills prior to performing the procedure. Whereas the traditional group reported a strong preference for continued live demonstrations of the procedure, the SLCM group stated that the computer-assisted module alone provided them with effective instruction.CONCLUSION:Computer-assisted learning is an acceptable and effective method of training students to pass an NG tube with potential welfare, proficiency, and knowledge advantages.

OBJECTIVE:To determine historical and clinical findings, treatment, and outcome for cattle with small intestinal obstruction caused by a trichobezoar.DESIGN:Retrospective case series.ANIMALS:15 cattle.PROCEDURES:Medical records of cattle with a diagnosis of small intestinal obstruction by a trichobezoar from 1992 to 2002 were reviewed. Information pertaining to various aspects of diagnosis, treatment, and outcome was collected from records.RESULTS:Trichobezoars were more common in young cattle, and affected cattle did not deteriorate clinically as rapidly as cattle with other types of intestinal obstruction. The most common initial owner complaints included decreased or absent fecal output, inappetance, abdominal distension, and signs of abdominal pain. Common clinical findings were dehydration, decreased or absent rumen motility, signs of depression, splashing sounds during succussion of the abdomen, and a pinging sound on percussion of the abdomen. The jejunum was obstructed in 10 cattle. Hypochloremic metabolic alkalosis and chronic inflammation were common laboratory findings. All 4 cattle that underwent abdominocentesis had peritonitis. The obstructing trichobezoar was removed surgically in 9 cattle, of which 7 survived and 2 died. The 6 cattle treated medically died or were euthanized.CONCLUSIONS AND CLINICAL RELEVANCE:Obstruction of the small intestine by a trichobezoar is uncommon, but it should be considered as a differential diagnosis in cattle with signs of intestinal obstruction, particularly if they are younger than 4 years of age and have a history of nonacute signs of intestinal obstruction. Surgical removal appears to be a favorable method of treatment and should be considered when this condition is suspected.