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in Journal of the American Veterinary Medical Association

SUMMARY

Aminoglycoside nephrotoxicosis (agnt) was induced in ewes by daily sc administration of gentamicin. Changes in urinary indices of renal function during the development of agnt are reported. Measurements from timed, volume-measured urine samples were made on days 0, 7, and 8 and included creatinine clearance, total excretion (te) rates of electrolytes (Na, K, Cl, P) and urine volume. Measurements from free-catch urine samples (without volume measurement) were made daily and included fractional excretion (fe) rate of electrolytes, urine osmolality, and urine-to-serum osmolality and urine-to-serum creatinine ratios. With the onset of agnt, FE rates of Na, K, Cl, and P increased many fold above baseline values (200 ×, 4 to 5 ×, 6 to 9 ×, and 70 to 95 ×, respectively, on days 7 and 8), indicating decreased tubular reabsorption or increased tubular secretion. The increased FE rates were not representative of increases in total electrolyte excretion rates. The total excretion of Na (TENa) was mildly increased, TEK was decreased, TECl was unchanged, and TEP was significantly increased on days 7 and 8. Abnormal urinalysis results, glucosuria, and increased FEP preceded appreciable increase in serum creatinine concentration. Other abnormal urinary indices of renal function coincided with or followed the increase in serum creatinine concentration. Urinary indices may help characterize renal function associated with the disease state, but did not provide early indication of agnt.

Free access
in American Journal of Veterinary Research

SUMMARY

Acute nephrotoxicosis was induced in ewes by daily sc administration of gentamicin. Activity of 3 urine enzymes, γ-glutamyltransferase (ggt), β-N-acetylglucosaminidase (ags), and β-glucuronidase (grs), were measured during the development of aminoglycoside nephrotoxicosis. Measurements from timed, volume-measured urine samples were performed on days 0, 7, and 8. Measurements from urine samples obtained without volume measurement (spot samples) were performed daily. Urine ggt and ags activities were high 3 days prior to detection of high serum creatinine concentration and 1.5 days before the appearance of casts in the urine sediment; values consistently remained in the abnormal range until termination of the study. High urine grs activity was inconsistent and transient; serum ggt activity did not change during the course of the study. Urine ggt and ags activities expressed as total excretion per unit time and body weight, enzyme activity per unit volume, and as ratio of urine enzyme activity to urine creatinine concentration were strongly correlated. Urine ggt and ags, but not grs activities, are suitable indicators of renal tubular cell damage in sheep with aminoglycoside nephrotoxicosis. Urine ggt and ags activities indicate cellular changes occurring several days prior to the first indications of renal functional change.

Free access
in American Journal of Veterinary Research

Summary:

Medical records of 83 cattle, which had 1 or more digit amputations performed at Kansas State University and The Ohio State University veterinary hospitals between 1971 and 1990, were reviewed. Signalment, duration of lameness, prior treatment, digit involved, and pathologic condition were evaluated. Owners were contacted with regard to the animal's duration in the herd after amputation and reason for exiting the herd, level of production attained, and degree of lameness. The animal was judged to have a good, fair, or poor recovery on the basis of this information.

Septic arthritis of the distal interphalangeal joint and resulting complications were the problems most frequently treated by digit amputation. Fifty-one percent of cattle undergoing digit amputation attained preamputation production levels for a minimum of 24 months. Approximately 30% of cattle undergoing digit amputation were culled for lameness, usually within 7 months of surgery. Cattle remaining in the herd more than 12 months after amputation were unlikely to be culled for lameness, indicating that long-term breakdown of supporting structures was uncommon. Likelihood of a good recovery decreased from 71.4% in cattle weighing ≤ 341 kg to 27.3% in cattle weighing ≥ 682 kg. Cattle undergoing amputation of a rear medial digit were more likely to recover well than those undergoing amputation of either front digit. The most frequently performed amputation was that of a rear lateral digit, but it was associated with the poorest recovery, possibly because of the disproportionate amount of stress placed on this digit. Cattle used for dairy and beef production had approximately equal chances of a good recovery from digit amputation. Duration of lameness prior to surgery and type of lesion did not influence recovery rates.

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in Journal of the American Veterinary Medical Association

Summary

A hospital-based case-control study was conducted to evaluate and compare risk factors for abomasal volvulus (av) and left displaced abomasum (lda) in cattle. Medical record abstracts were derived from 17 North American veterinary schools by the Veterinary Medical Data Program for all cattle admitted between Jan 1, 1977 and Dec 31, 1986, and for those with a diagnosis of av or lda. From a total of 108,956 individual cattle records, 1,036 cases of av and 7,695 cases of lda were identified, with a ratio of LDA to AV cases of 7.4 to 1. In-hospital mortality was 23.5% for av and 5.6% for lda.

Age, breed, gender, and season each had significant (P < 0.05) effects on risk for av and lda. Risk for av and lda increased with increasing age, with greater risk in cattle aged 4 to 7 years. Dairy cattle were at higher risk of developing av (adjusted odds ratio, 36.4) and lda (adjusted odds ratio, 95.2) than were beef cattle. The odds of AV in Brown Swiss cattle were significantly (P < 0.0001) lower, and the odds of lda in Guernsey cattle were significantly (P < 0.0001) higher than those in Holstein cattle. Female cattle were also at higher risk of developing av (adjusted odds ratio, 3.3) and lda (adjusted odds ratio, 29.1) than were male cattle. The odds of av and LDA varied considerably throughout the year, with the lowest number of cases observed in autumn. Seasonal development of AV differed significantly (P < 0.0001) from that of LDA, with the odds of av and lda being highest in January and March, respectively.

The medical records for all cattle with av and lda examined at the teaching hospital over a 10- and 5-year period, respectively, were reviewed, and the time interval since parturition, as well as the existence and nature of concurrent disease, were recorded. Proportionately fewer cases of av than lda developed during the first 2 weeks after parturition (28.3% of av cases vs. 57.0% of lda cases). Concurrent disease existed in 30.4% of av cases and 53.6% of LDA cases, with the rates of concurrent disease differing significantly (P < 0.0001) between the 2 groups. The mis-classification rate for data generated at the teaching hospital was estimated to be 6.5% for av and 5.3% for lda.

On the basis of the findings of this study, we hypothesize that: abomasal atony is a prerequisite for av and lda; existence of an abdominal void immediately after parturition facilitates development of AV and lda; normal rumen volume provides a moderately effective barrier against lda; risk of lda does not increase appreciably with advancing pregnancy; and the direction of abomasal displacement (av or lda) after abomasal atony and dilation is influenced principally by rumen volume.

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in American Journal of Veterinary Research

SUMMARY

Mycobacterial culture was performed on colostrum, milk, and feces from 126 clinically normal cows of a single herd with high prevalence of Mycobacterium paratuberculosis infection. Thirty-six (28.6%) cows were determined to be shedding the organism in the feces. Of the 36 fecal culture-positive cows, M paratuberculosis was isolated from the colostrum of 8 (22.2%) and from the milk of 3 (8.3%). Cows that were heavy fecal shedders were more likely to shed the organism in the colostrum than were light fecal shedders.

Free access
in American Journal of Veterinary Research

Summary

A prospective study evaluating the prognostic value of surgical and postoperative findings in 80 cattle with abomasal volvulus was performed. Surgical correction of abomasal volvulus was performed in all animals. After surgery, cattle were categorized into 3 groups: productive (acceptable milk production or appetite, n = 59), salvaged (poor milk production or appetite, n = 10), and nonsurvivors (n = 11). Cattle with omasal-abomasal volvulus had a significantly (P < 0.005) worse prognosis than cattle without omasal involvement. Large abomasal fluid volume, venous thrombosis, and blue or black abomasal color before decompression were all indicative of a poor prognosis. Most cattle had poor or fair appetites the first day after surgery; productive animals had marked improvement in appetite over the next 3 days. All cattle observed to have a good appetite within 3 days after surgery were later determined to be productive animals. The heart rate decreased in all groups after surgery; however, tachycardia (heart rate > 80 beats/ min) was sustained in cattle that were later salvaged for slaughter. Diarrhea was observed after surgery in 54% of cattle. The duration of diarrhea was significantly shorter (P = 0.009) in productive cattle than in salvaged and nonsurviving cattle. The presence or absence of diarrhea was only of predictive value when considered in conjunction with the estimated abomasal fluid volume.

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in Journal of the American Veterinary Medical Association

Summary

The hemodynamic effects of hypertonic saline solution (hss) resuscitation on endotoxic shock were examined in pentoharhital-anesthetized calves (8 to 20 days old). Escherichia coli (055:B5) endotoxin was infused iv at dosage of 0.1 μg/kg of body weight for 30 minutes. Endotoxin induced large decreases in cardiac index, stroke volume, maximal rate of change of left ventricular pressure (+ dP/dtmax), femoral and mesenteric arterial blood flow, glomerular filtration rate, urine production, and mean aortic pressure. Severe pulmonary arterial hypertension and increased pulmonary vascular resistance were evident at the end of endotoxin infusion. Treatment with hss (2,400 mosm of NaCl/L, 4 ml/kg) or an equivalent sodium load of isotonic saline solution (iss: 300 mosm of NaCl/L, 32 ml/kg) was administered 90 minutes after the end of endotoxin administration. Both solutions were infused iv over a 4- to 6-minute period.

Administration of hss induced immediate and significant (P < 0.05) increase in stroke volume and central venous pressure, as well as significant decrease in pulmonary vascular resistance. These effects were sustained for 60 minutes, after which all variables returned toward preinfusion values. The hemodynamic response to hss administration was suggestive of rapid plasma volume expansion and redistribution of cardiac output toward splanchnic circulation. Plasma volume expansion by hss was minimal 60 minutes after resuscitation.

Administration of iss induced significant increase in cardiac index, stroke volume, femoral arterial blood flow, and urine production. These effects were sustained for 120 minutes, at which time, calves were euthanatized. Compared with hss, iss induced sustained increase in mean pulmonary arterial pressure and only a small increase in mesenteric arterial blood flow. The rapid administration of large-volume iss appears superior to small-volume hss for initial resuscitation of acutely endotoxemic, anesthetized calves. At this time, we do not advocate rapid infusion of iss to septicemic calves because exacerbation of pulmonary hypertension may potentially depress respiratory function, and rapid increase in preload may hemodynamically compromise calves with depressed cardiac contractility.

Free access
in American Journal of Veterinary Research

Summary

The respiratory, renal, hematologic, and serum biochemical effects of hypertonic saline solution (hss) treatment were examined in 12 endotoxic, pentobarbitalanesthetized calves (8 to 20 days old). Escherichia coli endotoxin (055:B5) was infused iv at a rate of 0.1 μg/kg of body weight over 30 minutes. Endotoxin induced severe respiratory effects, with marked hypoxemia and increases in arterial-alveolar O2 gradient (P[A —a]O2), physiologic shunt fraction (Qs/Qt), and physiologic dead space to tidal volume ratio (Vd/Vt). Oxygen consumption was decreased, despite an increase in the systemic O2 extraction ratio. Peak effects were observed at the end of endotoxin infusion. The renal response to endotoxemia was characterized by a decrease in free-water reabsorption and osmotic clearance, as well as a decrease in sodium and phosphorus excretion. Endotoxemia induced leukopenia, thrombocytopenia, hyperphosphatemia, hypoglycemia, acidemia, and increased serum alkaline phosphatase concentrations.

Calves were treated with hss (2,400 mosm/L of NaCl, 4 ml/kg, n = 4) or an equivalent sodium load of isotonic saline solution (iss; 300 mosm/L of NaCl, 32 ml/kg, n = 4) 90 minutes after the end of endotoxin administration. Both solutions were infused over a 4- to 6-minute period. A control group (n = 4> was not treated. Infusion of hss or iss failed to induce a significant change in Pao2 , P(A-a)o2, (Qs/Qt), (Vd/Vt), or oxygen consumption. Both solutions increased systemic oxygen delivery to above preendotoxin values. Hypertonic saline infusion induced significant (P < 0.05) increases in serum Na and Cl concentrations and osmolality, whereas iss induced a significant increase in serum Cl concentration and a significant decrease in serum phosphorus concentration. Both hss and iss reversed the endotoxin-induced changes in renal function, with increases in free water reabsorption and osmotic clearance, as well as increases in sodium and phosphorus excretion. Sodium retention was greater following hss administration. On the basis of these findings, hypertonic saline solutions can be rapidly and safely administered to endotoxic calves.

Free access
in American Journal of Veterinary Research