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in Journal of the American Veterinary Medical Association

Abstract

Objective—To measure volatile fatty acid (VFA) concentrations and pH in the gastrointestinal tracts of healthy adult cats fed a commercial dry cat food.

Animals—14 cats.

Procedure—The gastrointestinal tracts were excised immediately after euthanasia and divided into 6 sections (stomach, duodenum, jejunum, ileum, proximal portion of the colon, and distal portion of the colon). Luminal contents were collected from each segment, pH was measured, and contents were centrifuged. The supernatant was analyzed for acetate, proprionate, butyrate, isobutyrate, valerate, and isovalerate concentrations by use of gas chromatography.

Results—Mean total VFA concentrations were lowest in the stomach (20 mmol/L); increased through the duodenum, jejunum, and ileum (30, 29, and 41 mmol/L, respectively); and were greatest in the proximal and distal portions of the colon (109 and 131 mmol/L, respectively). Estimated mean total VFA amounts were low (< 600 μmol) throughout all segments of the gastrointestinal tract; pH values increased from the stomach through the ileum and subsequently decreased in the colon.

Conclusions and Clinical Relevance—Total VFA concentrations in the colon were comparable to values reported for the forestomach of ruminants and large intestines of monogastric animals, whereas values in the small intestine were higher than reported for other species. Total VFA amounts were low, consistent with the short, nonvoluminous gastrointestinal tract of carnivores. Luminal pH varied throughout the gastrointestinal tract in a pattern similar to other monogastric animals. Volatile fatty acids probably contribute minimal metabolic energy in cats but may be important in the maintenance of local mucosal health. (Am J Vet Res 2000;61:359–361)

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in American Journal of Veterinary Research

Abstract

Objective—To compare secretory responses to prostaglandin (PG) E2 in mucosa obtained from the proximal and distal portions of the colon of dogs.

Sample—Colonic mucosa from cadavers of 18 clinically normal adult dogs.

Procedures—Short-circuit current (ISC) and maximum change in ISC (ΔIsc) in response to administration of 1μM PGE2 were measured across mucosa obtained from the proximal and distal portions of the colon. Responses were evaluated in mucosa (n = 6 dogs) incubated in Ussing chambers with or without 1 mM amiloride or without chloride in the Ringer's bathing solution. Responses were also evaluated in mucosa (n = 9 dogs) incubated with or without pretreatment with 1 μM indomethacin, with or without amiloride in the subsequent bathing solution. Histologic changes in mucosa from 3 dogs were assessed over time.

Results—ISC and ΔISC were significantly reduced when chloride was removed from, but not when amiloride was added to, the bathing solution and were significantly reduced after pretreatment with indomethacin. The ΔISC was significantly greater in mucosa from the distal portion of the colon than in the proximal portion of the colon. Histologic changes after incubation for 3 hours were minimal.

Conclusions and Clinical Relevance—ISC and ΔISC resulted from electrogenic chloride secretion. Chloride secretion was reduced when release of PGs was prevented by indomethacin and was induced by administration of PGE2. Chloride secretion in response to PGE2 was greater in mucosa from the distal portion of the colon than in mucosa from the proximal portion of the colon.

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in American Journal of Veterinary Research

Abstract

Objective—To compare guaranteed and measured concentrations of nutrients in commercial pet foods.

Design—Cross-sectional study.

Sample Population—Annual inspection reports of pet food analyses from 5 states.

Procedures—Guaranteed and measured concentrations of crude protein (CP), crude fat (CF), crude fiber (CFb), moisture, and ash in pet foods were compared. The concentration difference for each nutrient was compared among types of food, target species, target life stages, manufacturers, and laboratories.

Results—The guaranteed and measured concentrations of nutrients were significantly different. For all foods, mean concentration differences were as follows: CP, 1.5%; CF, 1.0%; CFb, −0.7%; moisture, −4.0%; and ash, −0.5%. Crude protein difference for treats was significantly larger than differences for dry and canned foods. Crude fat difference for dry foods was significantly less than differences for canned foods and treats. Crude fiber and moisture differences for canned foods were significantly less than the corresponding differences for dry foods and treats. Only CFb differences differed among target species, life stages, manufacturers, or laboratories.

Conclusions and Clinical Relevance—Addition of 1.5% and 1% to the guaranteed minimums for CP and CF, respectively; subtraction of 0.7%, 4%, and 0.5% from the guaranteed maximums for CFb, moisture, and ash, respectively; and addition of 0.23 kcal/g to the asfed metabolizable energy value calculated by use of modified Atwater factors from guaranteed analyses provides a more accurate estimate of the nutrient and metabolizable energy content of commercial pet foods. Nevertheless, the actual composition of a food should be determined whenever possible.

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in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To evaluate the effects of a flotation vest (FV) and water flow rate (WFR) on limb kinematics of dogs swimming against a current.

ANIMALS

7 (1 male and 6 female) healthy adult Siberian Huskies.

PROCEDURES

Dogs were habituated to swim with and without an FV beside an investigator in a continuous-flow pool against WFRs up to 2.9 km/h. During each of 4 experimental sessions in a repeated-measures study, markers were wrapped around the right carpus and tarsus, and a video was recorded while each dog swam with or without an FV for about 2 minutes at each of 7 WFRs between 0 and 2.9 km/h when the WFR was incrementally decreased or increased. Motion tracking software was used to measure stroke excursion and frequency.

RESULTS

Stroke excursion varied more than frequency among all dogs and in response to changes in experimental conditions. The male dog and 1 female dog were unable to complete the study. For the remaining 5 dogs across all experimental conditions, mean tarsus excursion was 30% that of the carpus. Mean total excursion (sum of the excursion-frequency products for the carpus and tarsus) decreased when an FV was worn and increased with WFR by 69% and 19% when WFR was incrementally increased and decreased, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

In dogs, range of motion during swimming was greater for the carpus than tarsus, when an FV was not worn, and increased more with WFR when WFR was incrementally increased. Those factors should be considered during swimming-based rehabilitation.

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether plasma concentrations of benzodiazepines (BDZ) in dogs following intranasal (IN) administration of diazepam are comparable to concentrations following IV administration.

Animals—6 (4 male, 2 female) healthy adult Greyhounds.

Procedure—Dogs were randomly assigned to 2 groups of 3 dogs in a crossover design. Diazepam (0.5 mg/kg of body weight) was administered intravenously to dogs in group 1 and intranasally to dogs in group 2. Blood was collected from the jugular vein of each dog into tubes containing lithium heparin before and 3, 6, 9, 12, 15, 20, 30, 60, 120, 240, and 480 minutes following diazepam administration. After a 4-day washout period, dogs in group 1 received diazepam intranasally, dogs in group 2 received diazepam intravenously, and blood was again collected. Plasma concentration of BDZ was determined by use of a fluorescence polarization immunoassay.

Results—Mean (± SD) peak plasma concentration of BDZ following IV administration (1316 ± 216 µg/L) was greater than that following IN administration (448 ± 41 µg/L). Time to peak concentration was ≤ 3 minutes following IV administration and 4.5 ± 1.5 minutes following IN administration. Mean bioavailability of BDZ following IN administration was 80 ± 9%.

Conclusions and Clinical Relevance—Diazepam is rapidly and efficiently absorbed following IN administration of the parenteral formulation. Plasma concentrations match or exceed the suggested therapeutic concentration (300 µg/L). Intranasal administration of diazepam may be useful for treatment of seizures in dogs by owners or when intravenous access is not readily available. (Am J Vet Res 2000;61:651–654)

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether mild restriction of food intake affects clinicopathologic variables, body composition, and performance of dogs undertaking intense sprint exercise.

Animals—9 trained healthy adult Greyhounds.

Procedure—Dogs were offered food free choice once daily for 9 weeks until body weight and food intake stabilized. Dogs were then randomly assigned to be fed either 85% or 100% of this quantity of food in a crossover study (duration of each diet treatment period, 9 weeks). Dogs raced a distance of 500 m twice weekly. Clinicopathologic variables were assessed before and 5 minutes after racing; food intake, weight, body composition, body condition score, and race times were compared at the end of each diet period.

Results—Compared with values associated with unrestricted access to food, there were significant decreases in mean body weight (by 6%) and median body condition score (from 3.75 to 3.5 on a 9-point scale) and the mean speed of the dogs was significantly faster (by 0.7 km/h) when food intake was restricted. Body composition and most clinicopathologic variables were unaffected by diet treatment, but dogs given restricted access to food had slightly fewer neutrophils, compared with values determined when food intake was unrestricted.

Conclusions and Clinical Relevance—Results indicate that the common practice among Greyhound trainers of mildly restricting food intake of racing dogs to reduce body weight does improve sprint performance. A body condition score of approximately 3.5 on a 9-point scale is normal for a trained Greyhound in racing condition. (Am J Vet Res 2005;66:1065–1070)

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in American Journal of Veterinary Research

Abstract

Objectives—To determine effect of α-tocopherol supplementation on serum vitamin E concentrations in Greyhounds before and after a race.

Animals—8 adult racing Greyhounds.

Procedure—Dogs were given 2 capsules of α-tocopheryl acetate (total, 680 units [0.5 g]) with food that contained ≤ 15 mg of vitamin E/kg each morning for 7 days. Dogs were exercised in a 30 × 30-m grass paddock for 15 minutes twice a day and raced for 500 m twice a week. Blood samples were collected before and 5 minutes after a race, before supplementation was begun, and after 7 days of supplementation. Blood and diet samples were analyzed for tocopherols and α-tocopheryl acetate.

Results—Before supplementation, serum α-tocopherol concentration after racing (mean ± SD, 6.7 ± 2.4 mg/L ) was significantly lower than before racing (12.2 ± 3.1 mg/L). After supplementation, α- tocopherol concentrations were significantly higher overall, although values obtained before (26.6 ± 5.2 mg/L) and after (29.8 ± 3.6 mg/L) racing were not significantly different.

Conclusions and Clinical Relevance—Supplementation with α-tocopheryl acetate increased serum α-tocopherol concentrations and eliminated the decrease in α-tocopherol concentration that was detected after a race, which may decrease oxidation during exercise and improve performance or recovery. (Am J Vet Res 2001;62:1118–1120)

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in American Journal of Veterinary Research

Summary

Campylobacter jejuni A74/O and A74/C are congenic strains. An oral dose of 105 organisms of strain A74/C colonizes chicken intestines. Strain A74/O, from which A74/C is derived, does not colonize the chicken intestines with an oral dose of 105 organisms. In this study, the congenic bacteria were compared to identify possible colonization mechanisms. Differences were not observed in plasmid content or by HindIII, Pst I, Acc I, HincII, Ava I, Ava II, Xba I, and BamHI restriction enzyme digestion of total dna. Transmission electron microscopy of negatively stained samples revealed no differences between the strains. Sections of cecal tissue from nonfed day-of-hatch chicks were cultured with each strain for 2 hours and then examined by light and electron microscopy. Both strains caused necrosis of villus epithelial cells. Immunofluorescent or silver staining revealed strain A74/C located deep in numerous epithelial crypts, but strain A74/O only was present in one sample mixed with sloughed necrotic cells. Similarly, organisms were detected by transmission electron microscopy deep in crypts in tissues cultured with A74/C, but not A74/O. Cells of A74/C detected in crypts did not appear to associate with epithelial cells. The strains did not differ in chemotactic behavior to mucin or fucose.

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in American Journal of Veterinary Research