Thoracic compliance measurements by use of readily available equipment were determined to be practical and safe in dogs. Twenty healthy dogs (age 1 to 16 years, weight 2.3 to 49.5 kg) were anesthetized for routine procedures such as dentistry or neutering. The animals were first hyperventilated to reduce pulmonary atelectasis, to check for leakage at the endotracheal tube cuff, and to induce mild hypocarbia, thus minimizing voluntary respiratory efforts. Total thoracic compliance measurements were calculated as the difference between exhaled volumes at static inspiratory pressures of 15 and 20 cm of H2O, divided by the pressure difference, and expressed as a function of body weight. The procedure was easy, took 5 to 10 minutes, and caused no recognizable ill effects in any of the dogs studied. Mean total thoracic compliance was 42.25 +/- 32 ml/cm of H2O. There was a significant correlation with weight, but no significant relationship was seen between compliance and age, or gender. The mean weight-adjusted total thoracic compliance was 1.85 +/- 0.56 ml/cm of H2O/kg. In studies in a small group of dogs with documented respiratory tract disease, 4 of 7 had a mean compliance > 2 SD below the normal range. Thus, this test may become part of the routine workup of any animal being anesthetized for procedures such as bronchoscopy to evaluate respiratory tract disease. Routine monitoring of animals on ventilators could provide early warning of complications such as pneumonia, pleural effusion, or pulmonary edema.

The effect of a high insoluble-fiber (IF) diet containing 15% cellulose in dry matter, high soluble-fiber (SF) diet containing 15% pectin in dry matter, and low-fiber (LF) diet on glycemic control in 6 dogs with alloxan-induced insulin-dependent diabetes mellitus was evaluated. Each diet contained > 50% digestible carbohydrate in dry matter. A crossover study was used with each dog randomly assigned to a predetermined diet sequence. Each dog was fed each diet for 56 days. Caloric intake was adjusted weekly as needed to maintain each dog within 1.5 kg of its body weight measured prior to induction of diabetes mellitus. All dogs were given pork lente insulin and half of their daily caloric intake at 12-hour intervals. Mean (+/- SEM) daily caloric intake was significantly (P < 0.05) less when dogs consumed the IF diet vs the SF and LF diets (66 +/- 3 kcal/kg, 81 +/- 5 kcal/kg, and 79 +/- 4 kcal/kg, respectively). Serum alkaline phosphatase activity was significantly (P < 0.05) higher when dogs consumed the LF diet vs the iF and SF diets (182 +/- 37 IU/L, 131 +/- 24 IU/L, and 143 +/- 24 IU/L, respectively). Mean postprandial plasma glucose concentration measured every 2 hours for 24 hours, beginning at the time of the morning insulin injection, was significantly (P < 0.05) lower at most blood sampling times in dogs fed IF and SF diets, compared with dogs fed the LF diet. As a result, 24-hour mean plasma concentration of glucose (IF, 165 +/- 17 mg/ dl; SF, 169 +/- 19 mg/dl; LF, 218 +/- 29 mg/dl), 24-hour mean plasma-glucose fluctuation (IF, 49 +/- 2 mg/dl; SF, 47 +/- 4 mg/dl; LF, 63 +/- 7 mg/dl), and 24-hour urine-glucose excretion (IF, 31 +/- 10 g/d; SF, 42 +/- 16 g/d; LF, 67 +/- 13 g/d) were significantly (P < 0.05) lower in dogs fed IF and SF diets, compared with dogs fed the LF diet. These variables were not significantly different between dogs fed IF and SF diets. Mean glycosylated hemoglobin concentration also was significantly (P < 0.05) lower when dogs consumed the IF diet, compared with the LF diet (4.3 0.4% vs 5.2 +/- 0.4%, respectively). In dogs with alloxan-induced insulin-dependent diabetes mellitus, consumption of diets containing 15% cellulose or 15% pectin and > 50% digestible carbohydrate on a dry-matter basis resulted in improvement in glycemic control, compared with consumption of a diet containing > 50% digestible complex carbohydrate without added fiber.

The growth of the heart, relative to body weight, was measured by M-mode echocardiography in dogs during the first year of life. Echocardiographic measurements were obtained from 16 English Pointers at 1, 2, 4, and 8 weeks of age and at 3, 6, 9, and 12 months of age. Left atrial (LA), aortic (AO), left and right ventricular internal dimensions, interventricular septal and left ventricular wall thickness measurements increased in curvilinear fashion relative to increasing body weight. Least-squares regression analysis, performed on logarithmically transformed data, was used to develop power-law equations describing the relationship of echocardiographic measurements to body weight. Linear dimensions of the LA, AO, left and right ventricular internal dimensions and interventricular septal and left ventricular wall thickness changed proportionally to slightly differing exponential powers of body weight (BW), varying from 0.31 to 0.45 (BW(0.31) to BW(0.45)). Fractional shortening and the LA to AO ratio decreased slightly, but significantly, as body weight increased. Indexing echocardiographic measurements to BW(1/3) was more appropriate than indexing such measures linearly to body weight, offering a practical method for developing accurate normative graphs or tables for M-mode echocardiographic dimensions in growing dogs.

Ultrasonic pachymetry was used to measure central, superior peripheral, and temporal peripheral corneal thicknesses of 75 dogs (150 eyes) with normal corneas, anterior chambers, and intraocular pressure. Mean corneal thickness averaged over the 2 eyes, 3 locations, and 75 dogs was 562 +/- 6.2 micromole. The peripheral cornea was thicker on average than the central cornea by 49.43 +/- 8.45 micromole and this difference increased with age at 6.97 +/- 1.3 micromole/month of age. Mean corneal thickness changed with age (14.23 +/- 2.26 micromole/month), and weight (1.83 +/- 0.38 micromole/kg). Females had significantly thinner corneas (22.43 +/- 11.03 micromole than males) after adjusting for age and weight.

Furazolidone cardiotoxicosis was induced in 2 groups (FZ and FZ-CR groups) of newly hatched male Pekin ducklings (100/group) by feeding a ration containing 650 mg of furazolidone/kg of feed (ppm) for 28 days. A third group (control ration, CR group; n = 100) was fed the same ration without furazolidone. On day 28, the control ration was initiated for the FZ-CR group initially given the furazolidone-containing ration, to allow recovery from the effects of the drug, whereas ducklings of the FZ group continued to consume the furazolidone-containing ration. Biweekly, beginning with week 4, ducklings were euthanatized to assess severity of gross lesions and to obtain sections of myocardium for histologic and ultrastructural examination. Clinical evidence (increased weight gain, increased feed consumption, decreased mortality, reduced prevalence of palpable ascites) of regression of cardiotoxicosis of ducklings of the FZ-CR group was nearly complete by day 56 (28 days after cessation of furazolidone intake). Likewise, regression of gross lesions, as measured by overall prevalence of gross lesions, left ventricular volume, and ascites prevalence and severity, were also essentially complete by day 56. Myofibrillar lysis was not seen in sections from the heart (examined ultrastructurally) obtained from ducklings of the CR group that were euthanatized on day 28, 56, or 98. Myofibrillar lysis was detected in all ducklings (4/4) fed furazolidone (FZ and FZ-CR groups) and euthanatized on day 28. Myofibrillar lysis was not seen in the heart of ducklings of the FZ-CR group that were euthanatized on day 56 or 98. Myofibrillar lysis was detected in the heart from all ducklings of the FZ group that were euthanatized on day 56. Leptomeres were observed in cardiac myocytes of ducklings that had been fed furazolidone, but not in those fed only the control ration. Our clinical, gross pathologic, and ultrastructural findings indicate that regression of the cardiac lesions of furazolidone toxicosis may be essentially complete by 28 days after cessation of furazolidone intake. Our ultrastructural findings indicate that furazolidone consumption may result in cardiac dilatation by altering myofibrillar/cytoskeletal attachments of myocytes.

Two diets similar in caloric density and mineral content, but markedly different in protein content, were used to study the effects of dietary protein on renal function and morphologic and histopathologic changes in dogs that had functional renal tissue reduced by seven-eighths nephrectomy. The effects of moderate protein intake (MPrI = 15% protein; dry-matter basis) and high-protein intake (HPrI = 31% protein; dry-matter basis) were studied for the initial 7 months (period 1 [P1]) after renal mass reduction. Diets were then switched between groups during the following 7 months (period 2 [P2]) to evaluate the effects of increased or decreased protein intake. The HPrI caused significantly (P < 0.05) greater glomerular filtration rate (GFR) and renal growth than did MPrI during P1. Dogs that maintained HPrI during P1 and MPrI during P2 (group 1) had significant (P < 0.05) reduction in GFR during P2. Dogs that maintained MPrI during P1 and HPrI during P2 (group 2) had significant (P < 0.05) improvement in GFR and renal growth during P2. At the end of the study, renal reserve was evaluated in both groups of dogs before and after group 1 was returned to HPrI for 2 weeks. During this 2-week feeding trial, group-1 dogs had marked improvement in renal reserve, relative to group 2, and GFR increased to the terminal P1 values. Results indicate a possible residual benefit from HPrI during the early phase of compensatory renal growth in the form of functional compensatory memory to HPrI. The severity of renal lesions was indistinguishable between dogs of dietary groups during both study phases. Plasma electrolyte concentrations rapidly returned to normal range after renal ablation, but mild azotemia and proteinuria persisted throughout most of the study. High protein intake was not associated with increased degree or progression of proteinuria.

Intervertebral disk space widths were measured on lateral radiographs of 73 anesthetized dogs. Weight was found to have a significant (P less than 0.01) effect on disk space width. Using weight-adjusted disk space width measurements for all subsequent studies, older (7- to 16-year-old) dogs and males had consistently, but not significantly, wider, disk spaces than did alternative groups. Cervical and lumbar intervertebral disk spaces tended to be wider than those in the caudal thoracic region. The widest cervical intervertebral disk spaces were C4-5 and C5-6 and the narrowest was C2-3. In the lumbar region, L2-3 was the widest disk space and L4-5 was the narrowest. Dachshunds generally had greater mean intervertebral disk space width than did other breeds of dogs. Cervical (n = 6 dogs) and thoracolumbar (n = 6 dogs) disk fenestration resulted in narrow intervertebral disk spaces, regardless of breed. When a ventral approach was used in thoracolumbar fenestration, the mean intervertebral disk space was narrower than that resulting from use of a dorsolateral approach. Spondylosis was found radiographically 1 to 4 years after intervertebral disk fenestration in 3 of 6 dogs that had cervical fenestrations and in 5 of 6 dogs that underwent thoracolumbar fenestration.

Five groups of Hereford steers were monitored for 293 days. One group of 3 was not given selenium supplementation; the other 4 groups of 3 steers each were given 2, 4, 6, or 8 reticulorumen selenium pellets. Health, body weight, and blood selenium concentration were monitored during the study. At the finish, steers were slaughtered, and various tissues from the carcasses were analyzed for selenium content. Initial blood selenium concentration did not differ significantly among groups. However, significant (alpha = 0.01) difference among means was detected during the early period of rapid increase in blood selenium concentration in steers of supplemented groups. Means of maximal blood selenium concentration also differed among groups; however, even the highest value, 0.253 microgram/g, was lower than the 3 microgram/ml reported in chronic clinical cases of toxicosis in the literature. Carcass analysis indicated significant (alpha = 0.05) differences in selenium concentrations among treatment groups for almost all tissues tested. Only kidney samples (7.9 microgram/g) from steers of the 8-pellet treatment group exceeded published normal values (7.6 microgram/g). Health variables for most dates were not significantly different among groups, and selenium toxicosis was not evident in any steer. Analysis did not indicate risk to human beings consuming tissues from these steers.