Fusobacterium necrophorum in ruminal contents and on the Fusobacterium necrophorum in ruminal contents and on the ruminal wall of cattle ruminal wall of cattle

Fusobacterium necrophorum was ruminal wall. The second was to determine quantified from ruminal contents and ruminal whether the concentration of F. necrophorum wall tissue collected at slaughter. Livers in ruminal contents and on the ruminal wall were examined and scored for abscesses. The was related to the occurrence of liver abmean concentration of F. necrophorum on scesses in cattle. the ruminal wall ranged from 2.9 × 10 to 6.1 3


Fusobacterium
necrophorum was ruminal wall.The second was to determine quantified from ruminal contents and ruminal whether the concentration of F. necrophorum wall tissue collected at slaughter.Livers in ruminal contents and on the ruminal wall were examined and scored for abscesses.The was related to the occurrence of liver abmean concentration of F. necrophorum on scesses in cattle.the ruminal wall ranged from 2.9 × 10 to 6.1 3 × 10 per cm .The dorsal sac had the lowest 5 2 counts, and dorsal blind and ventral sacs had the highest counts of F. necrophorum adher-In the first study, rumens were obtained ent to the ruminal wall.The concentrations immediately after slaughter from eight cattle of F. necrophorum in ruminal contents and fed a high-grain diet, and samples of ruminal on the ruminal wall did not appear to be contents and ruminal wall tissue were colrelated to presence or absence of abscessed lected.Tissue sections were taken from the

Introduction
Fusobacterium necrophorum is the pri-at a slaughter house.Livers were examined mary causative agent of liver abscesses in for abscesses and scored on a scale of 0 to feedlot cattle and is a normal inhabitant of the A+ with 0 being no abscess and A+ being one rumens of cattle.The concentration in the or two large or multiple small abscesses rumen ranges from 100,000 to a million cells (Table 1).The pH of ruminal contents was per gram of contents.Additionally, the measured immediately after collection.Samruminal ecosystem includes 'epimural bacte-ples were chilled and packed in ice and ria', which are adherent to the ruminal wall.
shipped by overnight delivery to the labora-Reports on the isolation of F. necrophorum tory.from the ruminal wall are limited and are almost always in relation to ruminal lesions.
Ruminal contents were blended for 1 Whether F. necrophorum is part of the nor-minute, strained through four layers of mal component of the ruminal wall population cheesecloth, and diluted anaerobically.Enuis not known.meration of F. necrophorum was by most-Two studies were conducted.One was to quantify F. necrophorum attached to the Experimental Procedures tral sac, and ventral blind sac.The pH of In the second study, ruminal contents and ruminal wall sections (from the dorsal sac only) were collected from 76 grain-fed cattle probable-number (MPN) technique using a selective culture medium dispensed in 96-well microtiter plates and incubated in an anaero-and 37 samples were from cattle with liver bic glove box.The plates were incubated for abscesses (liver score A-, A, and A+).Mean 48 hours and tested for indole production as pH of ruminal contents was similar between evidence of F. necrophorum growth.
groups.Of the 39 ruminal wall samples from Ruminal wall tissues were cut into 8 mm yielded no F. necrophorum growth.Of the circles with a biopsy punch, rinsed three times 37 rumen wall samples from cattle with liver in anaerobic medium, and minced in a homog-abscesses, 17 exhibited no F. necrophorum enizer.Serial dilutions of the suspension of growth.The mean F. necrophorum counts homogenized ruminal wall tissue were made from ruminal contents were 2.4 × 10 and .9anaerobically, and F. necrophorum was × 10 MPN/gram of DM from cattle with enumerated as before.
normal and abscessed livers, respectively

Results and Discussion
In the first study, the mean pH was 5.57, with normal levels and 8.4 × 10 /cm for and F. necrophorum counts of ruminal con-those with abscessed livers.None of the tents averaged 4.6 x 10 /gram of DM.The differences among groups for ruminal pH and 5 mean concentration of F. necrophorum on F. necrophorum counts in ruminal contents the ruminal wall ranged from 2.9 x 10 to and ruminal walls were statistically signifi-3 6.1 x 10 per cm .Some ruminal wall tissue cant.However, it is interesting that counts of 5 2 samples showed no F. necrophorum growth.F. necrophorum adherent to the ruminal wall The dorsal sac had the lowest counts, and the were numerically higher in cattle with abdorsal blind and ventral sacs had the highest scessed livers than in cattle with normal counts of adherent F. necrophorum (Figure livers.Further research is needed on F. 1).
necrophorum adherent to the ruminal wall in In the second study, 39 samples were numbers and their role in causing liver abfrom cattle with normal livers (liver score 0) scesses.
cattle with no liver abscesses, 14 samples 6 6 (Table 1).Additionally, the mean F. necrophorum counts from ruminal wall were 2.6 × 10 /cm for samples collected from cattle

Figure 1 .
Figure 1.Counts of Fusobacterium necrophorum Adherent to the Ruminal Wall in Cattle Fed High Grain Diets.

Table 1 . Fusobacterium necrophorum in Ruminal Contents and on the Ruminal Wall from Cattle with or without Liver Abscesses
to four well-organized abscesses under one inch in diameter; A+ = Liver has one or more large, or multiple small active abscesses with or without portions of the diaphragm adherent to the surface of the liver. a