Sampling Device

The present invention relates to a device for removing samples of milk from an animal, in particular a dairy animal such as a cow, goat or sheep, and to methods for extracting milk samples using the device.

It has long been recognised that it is difficult to collect milk samples in an aseptic manner. The environment found in for example dairy sheds or around herds of dairy cows is generally highly contaminated with food and faecal material, all of which makes it hard to extract samples in an aseptic manner .

In general, up to half the samples collected from dairy cows are found to be contaminated and cannot be used for bacteriological analysis. Furthermore, contaminated samples deteriorate rapidly, frequently before being tested, in particular where tests are conducted at remote locations.

This is a problem for example in the diagnosis of bacterial mastitis and when conducting quarter cell counting, as contamination can directly affect the results in those cases.

A device for aseptic sampling is described by Vangroenweghe et al., Vet. Res. 32 (2001), 565-579, in which a sample is taken via a sterile cannula which is linked to a collection bag by way of lengthy an infusion unit. Milk infuses into the bag under gravity.

The device however, is slow and unwieldy to use, requiring either support devices or multiple handlers to use.

According to the present invention, there is provided a device for extracting a milk sample from an animal, said device comprising a teat cannula having a channel for receiving milk,

and a connector arranged to sealingly interconnect the channel in the cannula with a container, said container being one in which the pressure is reduced or reduceable.

Containers in which the pressure is reducable are those which are specifically adapted to have pressure within them reduced without collapsing. Thus they will generally have rigid walls which can withstand small pressure changes. In addition, they are adapted to have the pressure in them .reduced, for example as a result of expansion of volume within a sealed chamber, such as is found for example in a syringe arrangement, or being provided with suitable connectors or valves for attachment to a pump able to withdraw air from within the container.

Containers in which the pressure is reduced are sealed containers in which a vacuum or partial vacuum exists.

By using a reduced pressure, for example a partial or complete vacuum to draw a sample through the teat cannula and into the container, asceptic samples from single quarters can be taken readily and quickly, by a single operative.

Suitably the device further comprises the container, which may be integral with the connector. Alternatively, the container may be a separate element that is for single use. However, in that case, the connector is specifically adapted to be able to sealingly interconnect with a container, for example by comprising a needle which can pierce a sealing membrane acting to close the container.

In one embodiment, the container comprises the barrel of a syringe arrangement. In this embodiment, the base of the cannula may be adapted to sealingly engage with the opening in the barrel of the syringe provided at the neck and which usually accommodates a needle, and this arrangement acts as the connector. In this embodiment, drawing down the plunger of the

syringe will reduce the pressure in the barrel, thus drawing a milk sample into the barrel of the container.

Alternatively, the container comprises a sealed vacuum container, such as those sold under the trade name Vacutainer®. In this instance, the container comprises a test tube that is sealed by means of a rubber cap comprising a membrane of a "self-sealing" material, as is known in the art. The container is at least partially evacuated so that pressure within the container is reduced. Therefore, when the cap is punctured, for example by means of a needle, sample is positively drawn into the container through the needle.

In this embodiment, the connector used to interconnect the cannula with the container includes a needle which can penetrate the cap. In particular the connector comprises a support, into which the base of the cannula can be fixed. The support further includes or may accommodate a needle, projecting in the opposite direction to the cannula.

The needle and/or cannula can be connectable to the support by any suitable means, including for example, Luer locks, adhesives or screw threaded interconnections.

Caps may be provided for one or both of the needle and cannula to ensure that they remain aseptic prior to use. The caps are suitably of a rubber or plastics material and may be held in place by means of a screw thread arrangement or they may be of the snap-fit variety.

In a particular embodiment, the support is adapted to engage with a needle holder, which can fit over the cap of the container so that the needle projects through the self-sealing cap of the container. In this way, when the cannula is in position within the teat, the needle holder may be placed over the cap of the container so that the needle pierces the cap.

A sample from within the teat is then drawn through the cannula and enters the container by way of the needle.

In a particular embodiment, the cannula is provided with multiple slots or holes, which open into the central channel, so as to minimise the risk that clots within the milk sample will clog up the device and prevent it from working. However, the fact that the device utilises reduced pressure to draw sample into the container will prove useful in this respect.

The cannula itself is suitably detachable from the support and disposable, so as to minimise waste. The support and/or the needle may then be sterilised for further use.

Thus in a further aspect, the invention provides a connector adapted for use in the device as described above. Cannulae specifically adapted for attachment to the connector may also be novel, and those with such specific adaptations form a further aspect of the invention.

Samples taken using the device described above are suitable for use in a variety of milk testing including quarter cell counting and bacteriology, and in particular in the diagnosis of mastitis.

They may be use to extract milk samples from any suitable animal including for example, cows, sheep, goats, camelids or equidae.

In a further embodiment, the invention provides a method for extracting a sample of milk from an animal, said method comprising inserting a cannula of a device as described above into the teat of said animal, if necessary, interconnecting the cannula with the container by way of the connector, and drawing sample into the container.

Where the cannula is integral with the container, for example in the form of a syringe, there will be no need to specifically interconnect the cannula with the container after insertion. It is merely necessary to draw out the plunger of the syringe so that the sample is sucked into the barrel of the syringe.

In a particular embodiment, the syringe is modified so that it may form a sealed container for transport of the sample. For example, the plunger of the syringe may be of a deformable plasties material. Once the sample has been sucked into the barrel by withdrawal of the plunger, the plunger may be bent or deformed so that it cannot inadvertently be reinserted into the barrel.

Alternatively or additionally, the region of the plunger extending outside of the barrel may be cut or otherwise removed, preferably at or in the region of the end of the barrel from which it projects. To facilitate removal of this end section, a notch may be provided in the plunger at an appropriate position along its length.

Suitably also the cannula is removable from the connector of the syringe and a sealing cap provided to replace it so that the connector of the syringe may effectively be closed. The cannula and cap may be attachable to the connector by means of a push fit, screw thread or the like

Where the container is of the Vacutainer® type, insertion of a needle in the support through the cap is necessary to effect the interconnection and to ensure that the drawing down occurs .

The invention will now be particularly described by way of example with reference to the accompanying diagrammatic drawings in which:

Figure 1 is a perspective schematic view of a device embodying the invention;

Figure 2 is a side section through of the device of Figure 1;

Figure 3 is an enlarged view of a cannula of the device;

Figure 4 illustrates an alternative embodiment of a device of the invention;

Figure 5 is a side view of an alternative embodiment of a device embodying the invention;

Figure 6 is a side view of the device of Figure 5 in which the cannula has been replaced with a cap;

Figure 7 is a side view of the device of Figure 6 where the plunger has been deformed after filling;

Figure 8 is a side view of the device of Figure 7 illustrating removal of an end region of the plunger of the syringe; and

Figure 9 is a side view of the device of Figure 8 after removal of the end region.

The device (Fig. 1) comprises a teat cannula (1) which is fixed to a support (2) . The support (2) further comprises a needle (3) which is in fluid communication with a central channel (4) in the cannula (1) and which extends in the opposite direction to the cannula (1) .

The support (2) is attachable to a needle holder (5) for example by means of a screw thread arrangement (not shown) .

In this instance, the container comprises a tube (6) which is at least partially evacuated, and which is sealed by means of a

cap (7) . The cap (7) includes a self-sealing membrane (not shown), which extends across a central aperture.

In use, the cannula (1) is inserted into the teat of an animal such as a cow, sheep or goat. The needle (3) is then pushed through the membrane of the cap (7) into the tube (6) . The reduced pressure within the tube (6) then draws a milk sample down from the teat, through the cannula (1) and needle (3) , into the container (6) .

When the sample has been taken, the cannula (1) may be removed from the teat and the needle (3) extracted from the cap (7) . On withdrawal of the needle (3) , the self-sealing membrane within the cap (7) immediately reseals the container (6) , thus isolating it from the environment and ensuring the integrity and sterility of the sample.

Where possible, the cannula may be detached from the support and discarded. The support (2) and or the needle holder (5) may then be reused.

Figure 3 shows an enlarged view of a particular form of a cannula (1) which may be used in the invention. The cannula includes not only a central channel (4) but a number of laterally arranged slots or holes (8) which feed into the channel (4) .

The channel (4) opens at the lower end into a needle (3) (although in this Figure, the connector is not shown) , which may be used to pierce a self-sealing membrane (9) of an evacuated tube (10). The support and needle holder (2,5) in this instance are shown schematically.

An alternative embodiment of the device is illustrated in Figure 4. In this case, the cannula (1) with the transverse holes (8) is fitted into the open neck (11) of a syringe (12) .

When the plunger (14) of the syringe (11) is withdrawn in the direction of the arrow, a partial vacuum is induced in the barrel (13) of the syringe drawing milk through the cannula (1) and directly into the barrel (13) , from where it may be transferred to a sterile container for testing.

In each case, sterile milk samples can be obtained easily and rapidly.

A further embodiment of the device is illustrated in Figures 5 to 9. In this instance, the device comprises a cannula (16) which is attachable to a body (17) of a syringe (15) by means of a connector (18) projecting from the body (17). The syringe (15) is provided with a plunger (19) of a deformable plastics material.

The illustrated device contains sample (20) which has been obtained by inserting the cannula into the teat of an animal such as a cow, and drawing out the plunger (19) .

A sample obtained in this way may be transferred to a separate container for transport. However, in the embodiment illustrated (Figure 6) , the cannula (16) is removed from the connector (18) and replaced by a push on cap (21) . This allows the syringe to effectively form a sealed body for the sample.

The use of the syringe as a storage element in this way may further be facilitated by deforming the projecting end portion (22) of the plunger (19), for example as shown in Figure 7. By deforming the end portion (22) of the plunger (19) which projects of the the body (17) out of alignment with the body (17) of the syringe, the accidental reintroduction of the plunger (19) into the body (17), an action which could lead to removal of the cap (21) and expulsion of the sample from within the body (17), is avoided.

In a particular embodiment however, the entire end portion (22) is removed, for example by cutting with scissors or the like, as illustrated in Figure 8. A notch (23) is suitably provided along the length of the plunger (19) to facilitate this operation. What remains (Figure 9) is a sealed container of sample, which can be transported for analyis with minimum risk of contamination.

In use, the animal such as the cow is restrained in a parlour. One operator holds tail and an anti-kick bar in place. All four quarters and udder are sprayed with surgical scrub to damp down any dust, and all four quarters are dried.

The quarter of interest is then surgically prepared. It is sprayed and cleaned and dried. This is repeated until no visual contamination can be seen either on the cotton wool or the teat. This important to minimise the risk of introducing bacteria in to the teat canal and therefore causing an e-coli or other mastitis or septicaemia. As such, it is suitably carried out by, or under the supervision of a veterinary surgeon.

The teat canal often contains bacterial contaminants so it is then emptied by drawing out the first 50-10OmI of milk (10-15 draws) . The teat is then sprayed and cleaned and dried again.

The sterile catheter of the device described above is then introduced and the sample drawn into the syringe. The syringe is then removed and stored safely until milking complete.

The quarter is then milked and the milk disposed of. Suitably, the quarter is then infused with an intra mammary antibiotic as directed by a veterinary surgeon.