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  • Author or Editor: Walter Grünberg x
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Abstract

Objective—To assess the suitability of the modified acetaminophen absorption test for evaluation of abomasal emptying rate in ruminating cattle.

Animals—7 Holstein-Friesian heifers.

Procedures—In a crossover study design, heifers consecutively underwent an IV infusion of 1 L of saline (0.9% NaCl) solution (control treatment), 1 L of saline solution containing metoclopramide (0.1 mg/kg), and 1 L of saline solution containing atropine (0.1 mg/kg), with an interval of 15 days between treatments. Immediately after each treatment, acetaminophen diluted in ethanol (50 mg/kg) was infused transcutaneously into the abomasum. Blood samples were obtained repeatedly for measurement of plasma acetaminophen concentration, and pharmacokinetic data were obtained.

Results—Maximum plasma acetaminophen concentration was significantly lower after atropine treatment than after control or metoclopramide treatment, whereas no difference was identified between control and metoclopramide treatments. The interval to maximum plasma acetaminophen concentration was significantly longer in atropine-treated versus metoclopramide-treated heifers. The interval to maximum acetaminophen concentration obtained from a pharmacokinetic model was significantly longer for atropine than for control and metoclopramide treatment. Similarly, areas under the plasma acetaminophen concentration-time curves for the first 60, 90, 120, and 240 minutes after administration were significantly lower for atropine versus metoclopramide or control treatment, whereas differences between metoclopramide and control treatments were not identified.

Conclusions and Clinical Relevance—The modified acetaminophen absorption test was a practical, minimally invasive, and reliable method to assess abomasal emptying in cattle. Metoclopramide administered at a dose of 0.1 mg/kg did not increase the abomasal emptying rate.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To identify potential mechanisms for hypokalemia in dairy cows with left-displaced abomasum (LDA), right-displaced abomasum (RDA), or abomasal volvulus (AV).

Design—Retrospective analysis of clinicopathologic data from 2 convenience samples of cows.

Sample—112 lactating dairy cows with AV (group 1); 1,332 lactating dairy cows (group 2) with LDA (n = 1,160) or RDA or AV (172).

Procedures—Data were analyzed via Spearman ρ and multivariate stepwise regression.

Results—78 of 112 (70%) group 1 cows were hypokalemic (mean serum potassium concentration, 3.5 mEq/L; reference range, 3.9 to 5.8 mEq/L). For group 1 cows, serum chloride concentration had the strongest positive association with serum potassium concentration, and serum potassium concentration was negatively associated with plasma bicarbonate and serum glucose, creatinine, and urea concentrations. Six hundred thirty-six of 1,160 (55%) of group 2 cows with LDA were hypokalemic (mean serum potassium concentration, 3.7 mEq/L). Ninety-two of 172 (53%) group 2 cows with RDA or AV were hypokalemic (mean serum potassium concentration, 3.8 mEq/L). For group 2 cows, serum chloride concentration had the strongest positive association with serum potassium concentration, and serum potassium concentration was negatively associated with indices of feed intake (serum bilirubin concentration) and hydration status.

Conclusions and Clinical Relevance—Results suggested hypokalemia was associated with hypochloremia, alkalemia, low feed intake with high amount of milk produced, hypovolemia, and hyperglycemia in lactating dairy cows. Treatment of hypokalemia should include surgical correction of abomasal displacement, increased dietary potassium intake via dietary dry matter intake or oral administration of KCl, and correction of hypochloremia, alkalemia, metabolic alkalosis, and dehydration.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To assess the acetaminophen absorption test (APAT) for use in determining function of the reticular groove reflex in lambs.

Animals—12 Baluchi lambs.

Procedures—2 consecutive APATs were performed at each of 3 developmental stages (stage 1, before weaning; stage 2, at weaning; and stage 3, after weaning). Lambs suckled a test solution consisting of acetaminophen and barium sulfate and 1 week later were tube fed the same test solution. Abdominal radiographs were obtained immediately after administration of the test solution. Plasma acetaminophen concentrations were determined before and 30, 60, 90, 120, 150, and 180 minutes after intake of the test solution.

Results—Closure of the reticular groove after suckling the test solution was confirmed in all 12 lambs at stage 1, in 8 lambs at stage 2, and in 0 lambs at stage 3. Maximum plasma acetaminophen concentrations and area under the plasma acetaminophen concentration-time curves from 0 to 180 minutes were significantly higher in lambs suckling the test solution, compared with values for tube-fed lambs. Receiver operating characteristics analysis revealed that the plasma acetaminophen concentration at 60 minutes after administration was best suited to determine closure of the reticular groove in lambs.

Conclusions and Clinical Relevance—Results suggested that the APAT can be a useful diagnostic instrument to assess function of the reticular groove reflex in lambs. We propose a cutoff value for the plasma acetaminophen concentration of 25 μg/mL at 60 minutes after administration to determine function of the reticular groove mechanism in lambs.

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effect of continuous IV administration of 50% dextrose solution on phosphorus homeostasis in lactating dairy cows.

Design—Clinical trial.

Animals—4 multiparous Jersey cows.

Procedures—Cows were administered 50% dextrose solution IV (0.3 g/kg/h [0.14 g/lb/h]) for 5 days. Plasma concentrations of glucose, immune-reactive insulin (IRI), and phosphorus were determined before, during, and for 72 hours after dextrose infusion. Phosphorus intake and losses of phosphorus in urine, feces, and milk were determined. Each cow received a sham treatment that included instrumentation and sampling but not administration of dextrose.

Results—Plasma glucose, IRI, and phosphorus concentrations were stable during sham treatment. Plasma phosphorus concentration decreased rapidly after onset of dextrose infusion, reaching a nadir in 24 hours and remaining less than baseline value for 36 hours. Plasma phosphorus concentration increased after dextrose infusion was stopped, peaking in 6 hours. Urinary phosphorus excretion did not change during dextrose infusion, but phosphorus intake decreased because of reduced feed intake, followed by decreased fecal phosphorus loss and milk yield. Rapid changes in plasma phosphorus concentration at the start and end of dextrose infusion were temporally associated with changes in plasma glucose and IRI concentrations and most likely caused by compartmental shifts of phosphorus.

Conclusions and Clinical Relevance—Hypophosphatemia developed in response to hyperglycemia or hyperinsulinemia in dairy cows administered dextrose via continuous IV infusion. Veterinarians should monitor plasma phosphorus concentration when administering dextrose in this manner, particularly in cows with decreased appetite or preexisting hypophosphatemia.

Full access
in Journal of the American Veterinary Medical Association