Objective—To develop nuclear scintigraphic and
acetaminophen absorption methods for measuring
abomasal emptying rate in suckling calves.
Animals—9 male Holstein-Friesian calves < 30 days
Procedure—Calves were fed 2 L of milk replacer,
fresh cow's milk, or an isoosmotic (150mM) solution
of NaCl, NaHCO3, or sodium acetate containing technetium
TC 99m-diethylenetriamine-pentaacetic acid
(370 MBq) and acetaminophen (50 mg/kg). Right lateral
scintigraphic images and venous blood samples
were obtained periodically after feeding. Two power
exponential equations were fitted to the scintigraphic
data, and 3 pharmacokinetic models were fitted to
the acetaminophen concentration–time data.
Results—Data from 32 feedings were analyzed, with
half emptying time for scintigraphic evaluation ranging
from 29 to 202 minutes. Siegel's modified power
exponential equation provided a better description of
the scintigraphic data than did Elashoff's power exponential
equation. The first derivative of Siegel's modified
power exponential formula provided the best
pharmacokinetic model for the acetaminophen
absorption data. Time to maximal acetaminophen
concentration (Tmax) provided the most accurate
index of abomasal emptying rate from the acetaminophen
Conclusions and Clinical Relevance—Abomasal
emptying rate is best determined in healthy suckling
calves by use of Siegel's modified power exponential
equation to model the scintigraphic data.
Pharmacokinetic calculation of Tmax from the acetaminophen
absorption curve provides an alternative
method for determining abomasal emptying rate in
healthy suckling calves that is accurate, inexpensive,
practical, and safe. However, it is unclear whether
diarrhea would alter the acetaminophen absorption
curve in calves. (Am J Vet Res 2005;66:364–374)
Objective—To develop and validate an ultrasonographic
method for measuring abomasal volume,
location, and emptying rate in suckling calves.
Animals—9 male Holstein calves < 40 days of age.
Procedure—Before and after calves were fed different
volumes of milk replacer or 2 L of oral electrolyte
solutions, ultrasonographic measurements of abomasal
dimensions (width, length, and height) were
obtained by applying a 3.5-MHz sector probe to the
ventral aspect of the abdomen in the transverse and
sagittal planes. Abomasal volume was calculated
from the ultrasonographic measurements by modeling
the abomasum as an ellipsoid and by use of a
power exponential equation to calculate the half-time
of abomasal emptying (t1/2).
Results—Preprandial abomasal volume was 20 to
137 mL. All 3 abomasal dimensions increased during
feeding and after suckling, and the abomasum was
symmetrically located about the midline of the ventral
aspect of the abdomen. Strong linear relationships
were identified between ultrasonographic and
suckled volumes, between ultrasonographic and
scintigraphic heights, and between ultrasonographic
and scintigraphic lengths. Ultrasonographic t1/2 was
linearly related to scintigraphic t1/2; the latter is
regarded as the gold standard measure of gastric
Conclusions and Clinical Relevance—Ultrasonographic
evaluation of the abomasum appears to provide
a practical, rapid, noninvasive, and accurate
method for determination of abomasal volume, location,
and emptying rate in suckling calves. (Am J Vet Res 2005;66:537–544)
Objective—To determine whether conscious, unsedated
cats will inhale a nebulized material administered
via a facemask and whether this material will
reach the lower airways.
Animals—20 healthy adult cats.
Procedure—Technetium Tc 99m-diaminetriaminopentaacetic
acid (99mTc-DTPA) was nebulized into a spacer
and administered to the cats via a closely fitting facemask.
By use of a gamma camera, images were then
immediately obtained to determine the distribution of
99mTc-DTPA within the lower airways.
Results—Images obtained by use of the gamma
camera revealed that all 20 cats had inhaled 99mTc-DTPA from the facemask. In each cat, deposition of
the radiopharmaceutical agent was evident throughout
the lung fields.
Conclusions and Clinical Relevance—Awake cats
that were not used to the application of a facemask
did inhale substances from such a device.
Aerosolization of medications may be a feasible route
of administration for cats with lower airway disease.
(Am J Vet Res 2004;65:806–809)
Objectives—To compare abomasal emptying rates in calves after suckling milk replacer or 3 common orally administered electrolyte solution components.
Animals—5 male calves < 35 days of age.
Procedures—Calves with a cannula fitted in the abomasal body were fed 2 L of milk replacer with or without parenteral administration of atropine (0.01 mg/kg, IV, then 0.02 mg/ kg, SC, q 30 min) or isotonic (150mM) solutions of sodium acetate, NaHCO3, or NaCl in a randomized crossover design. Abomasal emptying rates were determined via scintigraphy, acetaminophen absorption, ultrasonography, and change in abomasal luminal pH.
Results—Scintigraphic half-emptying time, time of maximal plasma acetaminophen concentration, ultrasonographic half-emptying time, and pH return time indicated similar abomasal emptying rates following suckling of isotonic sodium acetate, NaHCO3, and NaCl solutions, whereas the emptying rate of milk replacer was significantly slower. Mean maximal abomasal luminal pH was highest following suckling of NaHCO3 (pHmax = 7.85) and lowest following suckling of NaCl (pHmax = 4.52); sodium acetate (pHmax = 6.59) and milk replacer (pHmax = 5.84) yielded intermediate pH values.
Conclusions and Clinical Relevance—Isotonic solutions of sodium acetate, NaHCO3, and NaCl were rapidly emptied from the abomasum but varied markedly in their ability to alkalinize the abomasum. Sodium bicarbonate–containing orally administered electrolyte solution might increase the frequency of infection or severity of clinical disease in diarrheic calves treated for dehydration by causing prolonged abomasal alkalinization.