An Instrument for Collection and Transfer of Ruminal Fluid and for Administration of Water Soluble Drugs in Adult Cattle

The device consists of an oro-ruminal probe (Table 1, Fig. 1), a suction pump (Fig. 2), and a funnel. The probe can be connected to the pump (collection of ruminal fluid) (Fig. 3), to the funnel (administration of liquids or transfer of ruminal fluid) (Fig. 4) or to a water tap (cleaning) (Fig. 5) by means of a quick coupling connection. The pump consists of a pumping unit and a fluid container. Two fluid containers are available: one container with a capacity of 1l for collection of small samples, another with a capacity of 3 l for therapeutic purposes.


The Instrument
The device consists of an oro-ruminal probe (Table 1, Fig. 1), a suction pump (Fig. 2), and a funnel.The probe can be connected to the pump (collection of ruminal fluid) (Fig. 3), to the funnel (administration of liquids or transfer of ruminal fluid) (Fig. 4) or to a water tap (cleaning) (Fig. 5) by means of a quick coupling connection.The pump consists of a pumping unit and a fluid container.Two fluid containers are available: one container with a capacity of 1l for collection of small samples, another with a capacity of 3 l for therapeutic purposes.

Materials and methods
A precursor model of the actual probe was tested in 3 German Black Pied cows (Table 2) with ruminal fistulas.
8,10 1.The distance between the incisors and the ventral sac of the rumen was measured to determine how far the probe must be introduced.The mean distance was calculated by using the distance from the incisivi to the caudodistal end of the ventral sac of the rumen and the distance between the incisors and the most caudal point of the left 9th rib (cranial part of the ventral sac of the rumen).
2. For testing of the probe (30 applications prior to morning feeding) the following criteria were used: time necessary for introduction of the probe, volume of "spontaneous efflux" within 2 minutes, number of obstructions of the suction tube and number of obstructed holes Figure 1.Oro-ruminal probe *obtainable from: HEILAND, Albert-Schweitzer-Ring 5, 2 Hamburg 70, Germany KRUUSE, 5290 Marslev, Denmark in the probe's head during collection of 2l ruminal contents.The time required to administer 2l of ruminal fluid that had been collected by this probe, and for administration of 2l water via funnel and probe (15 administrations each) were also recorded.
3. Determination of the position of the probe's head in the reticulorumen by palpation via the fistula.This was performed prior to morning feeding and 3 to 4 hours after morning feeding (30 applications each).
4. Determination of the saliva contamination in the sample: Saliva contamination alters the pH-values and the sodium and potassium contents of ruminal fluid (increase of pH and sodium concentration, decrease of potassium concentration).Saliva contamination in a sample of ruminal fluid taken by an oro-ruminal probe may be detected by comparison of fluid collected by the probe and that collected via ruminal fistula by a rigid probe from the same location.
14 Collection by the ororuminal probe was performed after collection via the fistula in 15 cases, whereas in other 15 cases collection via the fistula was performed first.

Results
1.In adult German Black Pied cows, the probe had to be introduced at a length of 1.8 to 2.25m before its head reached the ventral sac ofthe rumen (Table 2).For further investigations, the probe was introduced at a length of 2.0m.
2. The introduction of the probe took an average time of 40 seconds.Within 2 minutes an average amount of 1.2 l ruminal fluid was siphoned off ("spontaneous efflux").In every case 2 l of ruminal fluid were obtainable using the suction pump.The suction tube never got plugged.Few holes of the suction head obstructed (average number: 7) but this did not hamper the collection.The administration of 2l of ruminal fluid or water was performed in an average time of 50 or 52 sec.(Table 3).
3. Prior to morning feeding, the probe's head was found in the antrum in 2 cows (7%), in 29 cases it was found in the ventral sac of the rumen (93%).Three to 4 hours after morning feeding, the probe's head was detected in the antrum in 3 cows (10%), in the middle of the rumen in 2 cases (7%), and in the ventral sac of the rumen in 25 animals (83%).
4. No significant differences in pH-values and concentrations of sodium and potassium were detected between samples collected by the oro-ruminal probe and samples collected by a rigid probe via the ruminal fistula from the same location within the rumen.The sequence of sample collection (oro-ruminal probe -ruminal fistula, and vice versa) had no significant effect on the differences (t-test) (Table 4).

Material and methods
The instrument used for trial A was slightly modified and tested in 106 healthy German Flecked cows.
11 Special emphasis was put on the question whether collection of 2l of ruminal fluid is possible and which time is the ideal for collection.The probe was introduced at a length of 2.0m either before morning feeding or 1 to 7 hours after morning feeding, respectively, and ruminal fluid was collected by using the pump.The time that was necessary to collect a volume of 2l of ruminal fluid was recorded and also the changes of the position of the probe necessary during collection.Time was taken from starting of the pump.The position of the probe was changed when no more ruminal fluid entered the fluid container.The probe was withdrawn at a length of 30cm to 1m and reintroduced to its original depth.

Results
In every case 2l of ruminal fluid were collected.An average time of 2¼ min.and an average number of 1.8 changes were necessary.The values for both parameters decreased up to 3 hours after morning feeding and increased thereafter.The best time for collection of ruminal fluid was observed prior to morning feeding (Table 5 and Fig. 6).

Discussion
In order to avoid saliva contamination, forestomach fluid used for diagnostic purposes should be collected from the ventral sac of the rumen.
7 Nasogastric tubes do not enter the ventral sac of the rumen.
2 If the presented probe is introduced as described herein to a length of 2.0m, head reaches the ventral sac of the rumen in most cases.Thus the probe is also suitable for siphoning off ruminal fluid.Rumen contractions probably induce "spontaneous efflux".
12 The instruments available in Germany up to now for rumen sampling often failed in the acquisition of ruminal content.The greatest problems were obstruction of the holes in the probe's head or the suction tube.This problem was resolved with our presented probe by drilling smaller holes in the probe's head and using a 1 to 4 ratio of the diameter of these holes to the diameter of the suction tube.Other problems in conventional rumen sampling devices arose from the aspiration apparatus.(The author started looking for an appropriate solution of this problem after sucking odiferous rumen content by mouth).Our suction pump produced sufficient vacuum to deliver rumen fluid in every case.A small amount of rumen fluid (500 ml) for diagnostic purposes is quickly obtainable (<0,5 min).
Saliva contamination due to introduction of the probe was not detected in the samples since no differ-ences (pH, Na, K) were found between samples collected by the probe and samples collected via ruminal fistula from the same location within the reticulorumen.Samples taken with other rumen sampling devices offer a saliva contamination between 8,9 and 19,6%.

7,14
The volume of the sample is determined by the amount of filterable fluid around the probe's head.The proportion of fluid in the rumen contents is lowest immediately after feed consumption and increases after bacterial fermentation of the ingested foodstuffs.It is greatest in the morning before the first feeding of the day.
5,6,7 Early morning and 3-4 hours after food intake were the best times for obtaining 2 l of ruminal fluid for therapeutic purposes.
Our device is also suitable for the transfer of rumen fluid and for administration of water soluble drugs, for example, following collection and evaluation of ruminal fluid.

5,6,7
After application the probe may easily be cleaned by connecting it to a water tap (Fig. 4).

Summary
An instrument for collection and transfer of rumi- nal fluid that is also suitable for administration of water soluble drugs for use in adult bovines is described.The device consists of an oro-ruminal probe, a suction pump, and a funnel.According to the results obtained by testing the device in a group of cows with rumen fistulas and a group of healthy cows, the instrument is suitable for collection of representative samples of ruminal fluid for diagnostic purposes and also for collection of larger volumes of ruminal fluid for transfer.Before morning feeding and 3-4 hours after food in take are the best times for obtaining larger volumes of ruminal fluid.

Figure 4 .Figure 5 .
Figure 4. Transfer of ruminal fluid using the ororuminal probe and the funnel

Table 1 .
Technical data of the probe

Table 5 .
Time necessary for collection of 2l of ruminal fluid (mean value t, maximum value tmax, minimum value tmin [sec]) and number of corrections of the position of the probe (mean value k, maximum value kmax, minimum value kmin) during n collections in relation to feeding (h: hours after morning feeding; h=0: prior to morning feeding).Time t (min) necessary for the collection of 2l of ruminal fluid and number of changes of the probe position k in relation to feeding