GB2490699A

GB2490699A - Flexible filter for a bolus device

Info

Publication number: GB2490699A
Application number: GB1107799.7A
Authority: GB
Inventors: Malcolm Bateman; Graham Menzies; Carl Perks
Original assignee: WELL COW Ltd
Current assignee: WELL COW Ltd
Priority date: 2011-05-10
Filing date: 2011-05-10
Publication date: 2012-11-14
Also published as: GB201107799D0

Abstract

A flexible filter adapted to engage with a bolus device. The invention provides the use of a flexible filter for the prevention of clogging of a bolus device whilst in use in the stomach of a ruminant and the use of a bolus device for monitoring a parameter, such as pH, or temperature, in the stomach of a ruminant. The flexible filter is a polypropylene, polyester, steel or photo-etched mesh. The mesh has apertures in the range 20 to 200 microns. The filter can be in the form of a bag or a tube.

Description

FILTER

Field of the invention

The present invention relates to a flexible filter for a bolus device. The bolus device typically comprises a pH or other sensor for monitoring a condition such as pH in the stomach of a ruminant.

Background to the invention

Up to 20% of dairy cows develop acidosis, a rumen pH of less than 5.5, after calving. A condition known as sub-acute rumen acidosis (SARA) may also be present in larger numbers of cows. This will reduce milk fat and milk output and in some cows cause more serious disease such as lameness, mastitis and sub-fertility.

SARA is an increasing health problem in most dairy herds in the US and has been estimated to cost the US dairy industry between $500m and $1 billion per annum. Results from field studies indicate a high prevalence of SARA in high-producing dairy herds as producers respond to the demands for increased milk production with higher grain, low fibre diets to maximize energy intake during early lactation. SARA poses a challenge for dairy farmers and dairy nutritionists to implement feed management practices to prevent or reduce the incidence of this disease.

Monitoring rumen pH levels in sentinel cows within a herd would provide farmers with important information indicative of the state of dietary health of the herd. When the sentinel cows exhibit increasing acidosis, this allows a farmer to adjust feeding to prevent major problems developing.

Current methods of monitoring the rumen pH are invasive veterinary procedures to collect fluid samples for off-line analysis or the use of wire connected pH sensors with data collection devices external to the animal. These sensors can be inserted through a cannula but are inferior to wireless telemetry devices which can be inserted orally into the animal.

Boluses are often inserted into the stomachs of ruminants, for example bolus devices containing sensors for monitoring ruminal conditions such as pH, magnetic boluses to attract metal ingested by the ruminant together with its food and drug boluses for controlled release of pharmaceuticals. Various bolus devices are known in the art.

For example, GB-245 5700-A discloses a bolus device with both a pH and temperature sensor.

The bolus comprises a pH electrode, a temperature sensor, a weight through which the pH sensor protrudes into the rumen, a microprocessor and radio.

US 2002/01563 56 Al relates to an apparatus and method for monitoring, in vivo, the ruminal p1-I of an animal. The apparatus comprises an external aspect at the outside of the animal, an indwelling ruminal aspect; and an intermediate aspect between the external and indwelling aspects. The indwelling aspect further has a pH sensor; and the external aspect further comprises a housing and a means for storing data from the pH sensor in said housing.

However, known bolus devices for monitoring rumen conditions are all susceptible to damage or blockage inside the rurnen by debris ingested by the ruminant together with its food. This can cause the device to cease working altogether and therefore shortens the usable lifetime of the device.

There is therefore a need in the art for a device that overcomes the problems associated with known monitoring devices and can therefore remain in use for much longer periods of time than known devices. There is also a need in the art for a device that can be inserted orally, and can therefore be used in any ruminant and not just in fistulated animals.

Summary of the invention

The present inventors have identified a problem with bolus devices used in the art to monitor ruminal conditions such as pH. Ruminants often ingest debris such as nails, barbed wire and stones together with their food, which cause damage to such bolus devices and in particular to the sensor, causing the device to stop working. The use of a rigid mesh to protect the sensor leads to further problems in that the mesh gets clogged very quickly with the animal's feed, i.e. seeds. The present inventors have devised a way of overcoming these problems associated with known devices, which leads to an extension of the lifetime of the devices and ensures the reliability of the readings taken from the device.

Accordingly, in a first aspect, the present invention provides a flexible filter adapted to engage with a bolus device.

Dctailed ctescription of the invention The present invention relates to a flexible filter for a bolus device. Sensors such as pH sensors rely on a constant flow of liquid to the sensor to allow the user to continue taking readings over an extended period of time. The flexible filter of the present invention allows the flow of liquid to and from the sensor to continue, such that liquid passes to the sensor and allows the user to continue taking readings, and does not get clogged with the animal's feed matter.

As used herein, the term "flexible" means deformable and not rigid.

As used herein, the term "filter" means a device that physically blocks certain substances whilst letting others through. A filter can therefore also be described as a selective membrane.

As used herein, the term "bolus" is used to refer to an object that is inserted into the stomach of an animal, preferably a ruminant. A "bolus device" as referred to herein is a device, such as a monitoring device, that is inserted orally into an animal. The bolus device is retained in the stomach of the animal in use, A "bolus device" as referred to herein is not intended to encompass a bolus of a drug or medicament.

As used herein, the term "mesh" takes means a semi-permeable barrier made of connected strands of metal, fibre or any other flexible material.

The flexible filter of the present invention allows the flow of liquid to and from the bolus device to continue. The flexible filter of the invention therefore blocks material such as rumen solids and seeds from entering the bolus device, whilst allowing liquid such as ruminal fluid to flow through.

The property of the flexible filter of the present invention being flexible enables it to be easily affixed to a bolus device. This property also prevents the filter from being damaged by the movement of the rumen, which pulsates during digestion of food. A rigid filter would be susceptible to breakage or damage by such activity.

The flexible filter of the present invention is adapted to engage with a bolus device. This means that the flexible filter is adapted to be attached to a bolus device. Accordingly, the flexible filter is of suitable size and dimensions that it can be attached to a bolus device.

Typically, the flexible filter is attached to the outside of a bolus device. In other words, the flexible filter can be described as a cover for the bolus device.

The bolus device with which the flexible filter of the invention engages typically comprises a sensor. In one embodiment, the sensor is a pH sensor arid/or a pH/redox sensor and/or a temperature sensor.

The flexible filter of the present invention will typically be used in combination with known bolus devices, such as that disclosed in WO 2006/046066.

In one embodiment, the bolus device is substantially tubular. The tubular bolus device can have open or closed ends, but typically has closed ends. The tubular bolus device is typically circular in cross-section. The flexible filter of the present invention is therefore of suitable dimensions that it engages with and can be attached to a substantially tubular bolus device as described herein.

In one embodiment, the flexible filter is adapted to engage with the whole bolus device, i.e. the bolus device is completely enclosed by the flexible filter when in use. However, the flexible filter of the present invention is typically adapted to engage with only part of the bolus device. In other words, the flexible filter is adapted to engage with part of the bolus device rather than the whole bolus device. This means that the flexible filter covers and/or is attached to part of the bolus device and not the whole bolus device when in use. In particular, in the embodiment of the invention where the bolus device comprises a sensor, the flexible filter is typically adapted to engage with only the part of the bolus device that includes the sensor. In other words, the flexible filter covers only the sensor when in use.

In one embodiment, the sensor is encased in a substantially tubular bolus device and the bolus device has one or more apertures surrounding the sensor, which allow fluid to flow in and out of the bolus device to and from the sensor. The tubular bolus device is typically circular in cross section. The tubular bolus device has proximal and distal ends, and the sensor is typically located at the distal end of the bolus device. The apertures are therefore typically also located at the distal end of the bolus device. This arrangement is shown in the Figures.

In one embodiment, the flexible filter of the invention covers the one or more apertures surrounding the sensor. In one embodiment, the flexible filter of the invention is circumferentially ananged around the bolus device such that it covers the one or more apertures. In this embodiment, the flexible filter of the invention can take the form of a bag or a tube, as described herein.

In one embodiment, the flexible filter is in the form of a bag. In this embodiment, the flexible filter is enclosed at one end and the other end is open. The bag is typically of a size that when in use the bag covers only the sensor part of the bolus device and not the whole bolus device.

Prior to use, the bolus device is inserted into the open end of the bag far enough so that the bag covers the sensor. The bag is typically then affixed to the bolus device proximal to the one or more apertures such that the sensor is covered and the bag is secured to the bolus device. This embodiment of the invention is shown in Figure 4.

In an alternative embodiment, the flexible filter is in the form of a tube, which is a flexible tube. In this embodiment, the flexible filter is open at both ends. The tube is typically of a size that when in use the tube covers only the sensor part of the bolus device and not the whole bolus device. Prior to use, the tube is fitted onto the bolus device by inserting the bolus device into one end of the tube and out the other end of the tube, and then the tube is positioned on the bolus device such that the tube covers the sensor. The tube is typically then affixed to the bolus device proximal and distal to the one or more apertures such that the sensor is covered and the tube is secured to the bolus device. This embodiment of the invention is shown in diagrammatical form in Figures 5 and 6. Figure 7 is a photograph of this embodiment of the invention.

The flexible filter is typically affixed to the bolus device by means of one or more gaskets, straps or bindings. The gaskets, straps or bindings must be secure enough to create a seal so that no debris is allowed to bypass the flexible filter of the invention and enter the bolus device. Any suitable gasket, strap or binding can be used to affix the flexible filter to the bolus device, for example rubber bands, zip ties or cable ties. Alternatively, the flexible filter can be affixed to the bolus device using another method, such as a sealant or adhesive, and/or by the flexible filter being moulded into the body of the bolus device.

The bolus device can be adapted for such means of affixation, for example by having one or more grooves into which the gaskets, straps or bindings fit. For example, in the embodiment of the invention where the flexible filter is a bag, the bolus device has a single groove into which a strap or binding can be applied for affixing the flexible filter to the bolus device. In the embodiment of the invention where the flexible filter is a tube, the bolus device has two grooves into which straps or bindings can be applied for affixing the flexible fitter to the bolus device. This is shown in Figure 8, which is a photograph of a bolus device adapted for affixation of the flexible filter of this embodiment of the invention.

The flexible filter of the present invention can be made of any flexible material. However, the flexible filter is typically in the form of a mesh and is typically a mesh bag or mesh tube. The flexible filter can be formed of any suitable material that is a mesh, but is typically formed of polypropylene, polyester mesh, photo-etched mesh or steel mesh. Thus in one embodiment, the flexible filter of the present invention is a polyester mesh filter bag. In one embodiment, the polyester is polyester monofitament cloth.

The mesh size of the flexible filter of the invention is such that it enables a flow rate of ruminal fluid into the bolus device that when the bolus device comprises a sensor, it allows the sensor in the bolus device to continue working, i.e. to take measurements of one or more ruminal conditions such as pH and/or temperature. The mesh size of the flexible filter will typically allow both inward and outward flow of ruminal fluid.

The mesh typically has apertures in the range of 20 to 200 microns, or jim. Typically, the apertures are in the range of from 50 to 100 microns, typically from 60 to 80 microns, more typically from 70 to 75 microns, more typically around 75 microns.

In a second aspect, the present invention provides a bolus device further comprising a flexible filter of the first aspect of the invention.

In the second aspect of the invention, the bolus device typically comprises a sensor, The sensor can be a pH, pH/redox and/or temperature sensor.

A typical bolus device according to this aspect of the invention is shown in the Figures herein, as follows.

Figure 4 shows a bolus device (1) having a flexible filter (2), wherein the flexible filter is in the form of a bag. The bolus device (1) is substantially tubular and has a plurality of apertures (3) surrounding a sensor (4), which allow fluid to flow in and out of the bolus device (1) to and from the sensor (4). The bolus device (1) has a proximal end (5) and a distal end (6), and the sensor is located at the distal end (6) of the bolus device (1). The apertures (3) are also located at the distal end (6) of the bolus device (1). The flexible filter (2) is circumferentially arranged around the bolus device (1) such that it covers the apertures (3) surrounding the sensor (4). The flexible filter (2) is attached to the bolus device (1) by means of a binding (7).

The bolus device (1) has two grooves (8) for optional attachment of further bindings (7).

Figure 5 shows a bolus device (1) having a flexible filter (2), wherein the flexible filter is in the fonn of a tube. The bolus device (1) is substantially tubular and has a plurality of apertures (3) surrounding a sensor (4), which allow fluid to flow in and out of the bolus device (I) to and from the sensor (4). The bolus device (1) has a proximal end (5) and a distal end (6), and the sensor is located at the distal end (6) of the bolus device (1). The apertures (3) are also located at the distal end (6) of the bolus device (1). The flexible filter (2) is circumferentially arranged around the bolus device (I) such that it covers the apertures (3) surrounding the sensor (4). The flexible filter (2) is attached to the bolus device (1) by means of two bindings (7), which fit into two grooves (8), one of which is proximal to the apertures (3), the other of which is distal to the apertures (3).

Figure 6 is an alternative view of the bolus device (1) shown in Figure 5.

The bolus device of the second aspect of the invention is typically for use in ruminants.

Ruminants are mammals that digest plant-based food by initially softening it within the animaPs first stomach (the rumen), then regurgitating the semi-digested mass, now known as cud, and chewing it again. Ruminating mammals include cattle, goats, sheep, giraffes, bison, moose, elk, yaks, water buffalo, deer, camels, alpacas, llamas, wildebeest and antelope.

Typically, the invention finds use in Cows. The invention will therefore be of use in the dairy fanning industry or in beef cattle. However, the invention may also find use with other agriculturally important species of animals, such as sheep, goats, etc. The bolus device of the second aspect of the invention can be inserted in the rumen of an animal using any suitable technique known in the art, and is typically inserted orally using a bolling gun. The bolus device then travels down the throat of the animal and into the rumen.

The bolus device typically contains a weight to assist transport of the device into the rumen and retention of the device in the rumen. The weight is typically located at the distal end of the bolus device, as shown in Figure 5. The bolus device is then retained in use in the rumen.

The flexible filter of the first aspect of the invention allows the bolus device of the second aspect of the invention to remain in use for much longer periods of time than known devices.

The lifetime of a bolus device of the second aspect of the invention is typically in the region of 20, 30, 40, 50, 60, 70, 80, 90 or up to 100 days. Such a lifetime ensures that a particular cow or herd of cattle can be monitored continuously in the critical period after calving. This in turn allows the user to optimise the milk cycle in a particular cow or herd.

As described herein, the flexible filter of the first aspect of the invention acts as a barrier or filter to block material such as rumen solids and seeds from entering the bolus device, whilst allowing liquid such as ruminal fluid to flow thiough.

Accordingly, in a third aspect, the present invention provides the use of a flexible filter of the first aspect of the invention for the prevention of clogging of a bolus device whilst in use in the stomach of a ruminant.

By "clogging" of a bolus device is meant blocking of a bolus device with solid matter.

Typically, clogging stops the bolus device from working, for example the sensor in the device stops taking readings.

In a fourth aspect, the present invention provides the use of a bolus device of the second aspect of the invention for monitoring a parameter in the stomach of a ruminant.

In a fifth aspect, the present invention provides a method for monitoring a parameter in the stomach of a ruminant, comprising: (a) administering a bolus device of the second aspect of the invention to said ruminant; and (b) taking measurements of said parameter using said bolus device.

In the third to fifth aspects of the invention, the stomach of the ruminant is typically the rumen.

In the fourth and fifth aspects of the invention, the parameter is typically pH andlor temperature. The temperature in the stomach of a ruminant can be used as an indication of core temperature of the animal.

In the fifth aspect of the invention, step (a) is typically carried out using a boiling gun.

Step (b) typically involves taking a plurality of measurements over time, for example a period of time of up to 100 days, for example a period of time of 1, 2, 4, 7, 10, 14, 20, 21, 28, 30, 35, 40, 42, 49, 50, 56, 60, 63, 70, 77, 80, 84, 90 or up to 100 days. Measurements can be taken at any suitable frequency over this time period, for example daily, weekly or every 2, 3 or 4 days or every 2, 3, 4 or S weeks. As mentioned above, the extended lifetime of a bolus device of the second aspect of the invention allows the user to monitore a particular cow or herd of cattle continuously in the critical period after calving. This in tum allows the user to optimise the milk cycle in a particular cow or herd. Step (b) can also include recording data from the bolus device.

Preferred features for the second and subsequent aspects of the invention are as for the first aspect mutatis mutandis.

The present invention will now be further described by way of reference to the following Example which is present for the purposes of illustration only. In the Example, reference is made to a number of Figures in which: FIGURE 1 shows a bolus device encased in a flexible filter of the invention prior to being inserted into the rumen of an animal.

FIGURE 2 shows a bolus device as described in the Comparative Example with a damaged etched mesh.

FIGURE 3 shows two bolus devices that have been removed from the rumen of a dairy cow. The bolus on the left was protected using the flexible filter of the invention and the bolus on the right was not. As can be seen from the Figure, the bolus device on the right is clogged by debris from the rumen.

FIGURE 4 is a drawing of one embodiment of the invention, where the flexible filter of the invention does not cover the whole bolus device, but only covers the sensor. In this embodiment, the flexible filter of the invention is a bag.

FIGURE 5 is a drawing of another embodiment of the invention, where the flexible filter of the invention does not cover the whole bolus device, but only covers the sensor. In this embodiment, the flexible filter of the invention is a flexible tube.

FIGURE 6 is an alternative view of the embodiment of the invention shown in Figure 5.

FIGURE 7 is a photograph of the embodiment of the invention shown in Figures 5 and 6.

FIGURE 8 is a photograph of a bolus device adapted for affixation of the flexible filter showninFiguresto 7.

Cmparative Exanjpjç A bolus device having a steel mesh supported by a plastic frame was tested. Prototypes having two different mesh sizes of 70 microns and 140 microns were tested. Initially, a simple liquid test was conducted to assess how it flowed through the mesh holes plus the devices were inserted into a container with foreign objects i.e. stones, nails etc to see how they stood up. Indications were that the prototype looked as though it might function as required.

The prototypes were then inserted, without sensors and electronics, into fistulated cows for two weeks, After two weeks the devices were inspected. It was found that they had both performed well as regards any physical damage but on looking inside it was found that the micron prototype had let in a substantial amount of solid matter which suggested that it was likely to get blocked over the target of 100 days. The 70 micron prototype showed more promising results.

A prototype having the 70 micron mesh was then fully assembled with sensor, batteries, electronics etc and inserted back into a fistulated cow to assess its ability to record pH levels.

On retrieval after 13 days it looked good with no blockage and relatively free flow of rumen fluid, however no data had been recorded and on inspection it was discovered the battery had leaked out and was flat. The prototype was refurbished, the battery was replaced and the prototype redeployed.

A further prototype was refurbished using etched mesh and deployed in a fistulated cow. It was discovered that the calibration check was off and the response was slow. It appeared that too much liquid/solid matter was getting in, possibly by getting past the filter. To try to rectify this, the mesh was sealed in place with silicon and/or rubber gaskets. A further prototype was refurbished, fitted with etched mesh and sealed up and then deployed in a fistulated cow.

Both units were retrieved; both etched meshes failed as the material was too weak; both units were unresponsive as too much fluid was still getting in. The damaged etched mesh is shown in Figure 2.

Example -use of flexible filter It was decided to investigate the use of polyester mesh to encase the bolus to test the technology. It was felt that if the mesh was tailored to fit' the bolus it would be possible to insert into a cow using a bolling gun.

A prototype was prepared with all the mesh removed from the apertures in the bolus device.

The bolus device was just left fitted with the inner framework (i.e. the material around the aperwres) to provide protection to the sensor against foreign objects such as stones, nails etc. Grooves were cut into the outer surface to take rubber rings. A mesh filter bag was fitted to the outside and attached using rubber rings over the grooves.

The first prototype showed no response when placed in buffer; the head was removed to find it full of material which was quite easily cleaned under a tap. A further prototype was therefore refurbished with a new probe and deployed in a fistulated cow. l0

Figure 3 shows two bolus devices that have been removed from the rumen of a fistulated cow.

This Figure shows the results obtained with the flexible filter of the invention (left) and the prototype with the etched mesh described in the Comparative Example (right). As can be seen from Figure 3, the bolus device from the Comparative Example is clogged by debris from the rumen, whereas the bolus device which was in the mesh bag according to the present invention was not.

A bolus device according to the present invention was then inserted orally into a cow using a bolling gun and data was recorded from the cow using the bolus device.

Claims

CLAIMS1. A flexible filter adapted to engage with a bolus device.
2. A flexible filter according to claim 1, wherein the bolus device comprises a sensor.
3. A flexible filter according to claim 2, wherein the sensor is a pH sensor, a pHlredox sensor and/or a temperature sensor.
4. A flexible filter according to any one of claims 1 to 3, wherein the flexible filter is adapted to engage with only part of the bolus device.
5. A flexible filter according to claim 4 when dependent upon claim 2 or 3, wherein the flexible filter covers the sensor.
6. A flexible filter according to claim 4 or 5, wherein the flexible filter is in the form of a bag or a tube.
7. A flexible filter according to any one of the preceding claims, wherein the flexible filter is a mesh.
8. A flexible filter according to claim 7, wherein the mesh is a polypropylene mesh, a polyester mesh, a steel mesh or a photo-etched mesh.
9. A flexible filter according to claim 7 or 8, wherein the mesh has apertures in the range of from 20 to 200 microns.
10. A flexible filter according to claim 9, wherein the mesh has apertures in the range of from 50 to 100 microns.
11. A flexible filter according to claim 10, wherein the mesh has apertures in the range of from 70 to 75 microns.
12. A bolus device further comprising a flexible filter according to any one of the preceding claims.
13. A bolus device according to claim 12, wherein the bolus device comprises a sensor.
14. A bolus device according to claim 13, wherein the sensor is a pH sensor, a pI-1/redox sensor and/or a temperature sensor.
15. Use of a flexible filter according to any one of claims 1 to 11 for the prevention of clogging of a bolus device whilst in use in the stomach of a ruminant.
16. Use of a bolus device according to any one of claims 12 to 14 for monitoring a parameter in the stomach of a ruminant.
17. Use according to claim 16, wherein said parameter is pH, pl-L/redox and/or temperature.
18. A method for monitoring a parameter in the stomach of a ruminant, comprising: (a) administering a bolus device according to any one of claims 12 to 14 to said ruminant; and (b) taking measurements of said parameter using said bolus device.
19. A method according to claim 18, wherein said parameter is pH, pHfredox and/or temperature.
20. A method according to claim 18 or 19, wherein step (a) is carried out using a bolling gun.