Objective—To describe myoelectric patterns in the
intestines of cows after electrode implantation.
Animals—7 lactating Simmental-Red Holstein cows.
Procedure—Cows were implanted with 7 pairs of
bipolar silver electrodes (1 each in the ileum, cecum,
and proximal loop of the ascending colon (PLAC) and
4 in the spiral colon). Myoelectric activity was monitored
during 10 periods within the first 3 weeks after
surgery. Recordings from the first 2 weeks were
compared with recordings from the third week, which
was considered a steady-state condition.
Results—Significant changes over time were detected
for 18 of 57 variables, including 3 variables describing
myoelectric activity of the ileum, 6 variables of the
cecum, 6 variables of the PLAC, and 3 variables of the
spiral colon. Compared with values for the steadystate
condition, 16 variables differed significantly for
the 14-day period after surgery (7 variables until day
11, 2 variables until day 8, 4 variables until day 5, 1
variable until day 3, and 2 variables until day 2 after
electrode implantation). None of the variables had significant
changes that lasted only 1 day after surgery.
Conclusions and Clinical Relevance—Significant
changes were observed for several variables of myoelectric
activity in all intestinal segments until as late
as 11 days after electrode implantation, whereas a
steady-state condition was reached 14 days after
surgery. Effects of drugs, manipulations, or nutrition
regimens on myoelectric activity of the bovine digestive
tract should be evaluated no sooner than 2 weeks
after electrode implantation. (Am J Vet Res 2004;65:797–805)
Objective—To characterize and compare in vitro contractility
patterns of sections of abomasal wall harvested
from cattle of 3 dairy breeds.
Sample Population—Longitudinal and circular
smooth muscle preparations harvested from the
antrum and body of the abomasum of 30 recently
slaughtered Holstein-Friesian, Brown Swiss, and
Simmental X Red Holstein cows.
Procedure—Spontaneous isometric contractions of
specimens in tissue baths of modified Krebs solution
were recorded during a 4-hour period. Maximal amplitude,
frequency of contractions, and change of basal
tension were used to characterize contractility.
Statistical analyses were used to test for differences
among time periods, among breeds, between specimen
locations, and between fiber orientations.
Results—Myoactivity patterns of abomasal smooth
muscle preparations are highly variable and differ on
the basis of location and fiber orientation. Frequency
of contractions differed significantly among time
periods for longitudinally oriented specimens with
decreasing frequencies of contractions over time.
Maximal amplitude of the longitudinally oriented
specimens from the antrum increased significantly,
whereas maximal amplitude of the circularly oriented
specimens from the antrum decreased significantly.
Values did not differ significantly among
Conclusions and Clinical Relevance—Patterns of
spontaneous contractility of abomasal wall specimens
are not homogeneous. During a 4-hour recording
period, maximal amplitude and frequency of contractions
of specimens varied significantly with
respect to orientation and location; however, spontaneous
contractile myoactivity did not differ significantly
among breeds. Therefore, breed predisposition
for displaced abomasum is not correlated with spontaneous
activity of smooth muscle specimens. (Am J
Vet Res 2002;63:1687–1694)