INTERNAL TEAT SEALANTS AND THEIR USE IN THE PREVENTION OF BOVINE MASTITIS IN THE DRY COW

Abstract

An intramammary syringe contains a seal formulation for forming a physical barrier in the teat canal of a non-human animal. The syringe contains a reduced volume of from 0.25 ml to 2.0 ml of the seal formulation. The problem of ascending sealant during the dry period is solved.

Claims

1. An intramammary syringe containing a seal formulation for forming a physical barrier in the teat canal of a non-human animal wherein the syringe contains from 0.25 ml to 2.0 ml of the seal formulation.

2. An intramammary syringe as claimed in claim 1 wherein the syringe contains from 0.5 ml to 2.0 ml of the seal formulation.

3. An intramammary syringe as claimed in claim 1 wherein the syringe contains from 0.75 ml to 1.75 ml of the seal formulation.

4. An intramammary syringe as claimed in claim 1 wherein the syringe contains from 1.0 ml to 1.5 ml of the seal formulation.

5. An intramammary syringe containing a seal formulation for forming a physical barrier in the teat canal of a non-human animal wherein the syringe contains from 0.5 g to 2.5 g of the seal formulation.

6. An intramammary syringe as claimed in claim 5 wherein the syringe contains from 1.0 g to 2.5 g of the seal formulation.

7. An intramammary syringe as claimed in claim 5 wherein the weight of the seal formulation contained in the syringe is from 1.5 g to 2.0 g.

8. An intramammary syringe as claimed in claim 5 wherein the seal formulation comprises a heavy metal salt in a base.

9. An intramammary syringe as claimed in claim 8 wherein the heavy metal salt is bismuth subnitrate.

10. An intramammary syringe as claimed in claim 9 wherein the bismuth subnitrate comprises approximately 65% wt of the seal formulation.

11. An intramammary syringe as claimed in any of claims 10 wherein the seal formulation comprises a thixotrophic agent.

12. An intramammary syringe as claimed in claim 11 wherein the seal formulation contains from 0.1% to 1.5% of the thixotrophic agent.

13. An intramammary syringe as claimed in claim 11 wherein the seal formulation contains from 0.6 to 1.0% of the thixotrophic agent.

14. An intramammary syringe as claimed in claim 11 wherein the seal formulation contains approximately 0.8% of the thixotrophic agent.

15. An intramammary syringe as claimed in claim 14 wherein the thixotrophic agent comprises colloidal anhydrous silica.

16. An intramammary syringe as claimed in claim 15 wherein the base is a gel based on aluminium stearate.

17. An intramammary syringe as claimed in claim 16 wherein the base includes liquid paraffin as a vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The invention will be more clearly understood from the following description thereof, given by way of example only, in which:

[0042] FIGS. 1 and 2 are x-ray studies of teats into which an internal teat sealant has been infused.

DETAILED DESCRIPTION

[0043] When cows are dried off, a process known as involution occurs within the udder. Involution has three distinct phases.

[0044] 1) Active Involution

[0045] The first of these stages is known as active involution and, depending on the time remaining to calving (and consequently the length of the dry-period), this will usually be complete within 21 to 30 days. During this time the udder more or less maintains it's pre-dry off state, with milk continuing to accumulate for approximately 4 days and then declines rapidly over the next week. Fluid volume continues to decrease through 30 days (in a 45-60 day dry-period).

[0046] 2) Steady State Involution

[0047] As the volume of fluid reduces, the udder shrinks considerably (upwards and inwards) in size. The cow is now in steady state involution.

[0048] We have discovered that as the udder shrinks, during this state, so does the available area within the teat canal, sometimes leaving an area inadequate to accommodate the seal volume. Such is the pressure within the shrinking teat cistern that the internal teat sealant can be torn apart, with portions of it being forced up into the udder. It has been observed that the teat sealant plug, which has earlier formed in the teat cistern, can in some cases be forced upwards in its entirety into the gland cistern.

[0049] The length of the steady state period depends on the total length of the dry period. If active involution takes in the region of 4 weeks to complete in the dairy cow and the redevelopment stage takes about 3 or 4 weeks. These periods will then account for the recommended optimal 45-60 day dry period. Accordingly, cows with a 45-60 day dry period probably have a very short steady state phase, or no steady state phase of involution, at all. In instances where no steady state occurs, there is little or no pressure on the internal teat sealant.

[0050] 3) Colostrogenesis

[0051] During the third phase of the dry-period, known as colostrogenesis and lactogenesis, the udder and teats begin to expand again.

[0052] This phase of the dry period marks the transition from the non-lactating state to the lactating state. It is not known exactly when this period begins, but it usually occurs around 3 to 4 weeks before calving occurs.

[0053] During this time the volume of the teat canal increases, often allowing non-bound particles of internal teat sealant that have been forced up into the udder during steady state involution, settle back into the teat cistern. However, studies have also shown that some particles of internal teat sealants that have been forced upwards become bound to the mammary tissues in the udder and will stay up there and sometimes for some days post calving. Where this occurs, it is often only when the cow has been milked on a number of occasions that these particles will detach from the mammary tissues and will become mixed with the milk. In instances such as this, the particles of internal teat sealant are known to either lodge in the milk lines or on occasions can make it through to the milk collection point.

[0054] We have surprisingly discovered that when a smaller volume of teat sealant is initially infused the likelihood of it being forced upwards from the teat cistern into the gland cistern is significantly reduced, or eliminated entirely.

EXAMPLE 1

Teat Seal Formulation

[0055]

TABLE-US-00001 Component Quantity per g Quantity (% w/w) Bismuth Subnitrate 650.0 mg 65% Colloidal Anhydrous silica 8.0 mg 0.8% Aluminium di/tri stearate 48.0 mg 4.8% Liquid paraffin, Heavy q.s. 1 g q.s. 100%

[0056] The formulation above was prepared by the following process:

[0057] Liquid paraffin, heavy is added to a vessel.

[0058] Aluminium di-/tri stearate is added to the liquid paraffin, heavy, stirred and heated to a minimum of 150 C.

[0059] The mixture is maintained at this temperature for a minimum of 3 hours.

[0060] The mixture is cooled and the Bismuth Subnitrate and Colloidal Anhydrous Silica is then added and mixed until homogenous.

[0061] The product is then filled into intramammary syringes. The amount filled into the syringe is from 0.5 to 2.0 ml or 1.0 g to 2.5 g to be administered as a single dose.

[0062] The filled syringes may be sterilised by gamma irradiation.

EXAMPLE 2

Use of the Teat Seal Formulation

[0063] Studies have shown that by reducing the conventionally accepted dose of 4 g per teat at drying off, down to between 0.5 g and 2.5 g, the effectiveness of the internal teat sealant is not diminished, but that the problem of ascending internal teat sealant during involution is eliminated.

[0064] The invention is not limited to the embodiments hereinbefore described, which may be varied in detail.