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This article was published in 1968-69
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The Mastitis Problem
K. G. JOHNSTON, B.V.Sc., Dip.Bact.(Lond.), School of Veterinary Science, Rural Veterinary Centre, Camden.
The mastitis problem may be approached from a number of aspects.
THE READING FIELD TRIALS
Neave, Dodd, Kingwill (1966 Vet. Rec. 78:521) in their endeavours to get hygiene systems on a practical basis and adequately documented as effective, have large field trials under way. Data is now available on three types of hygiene, viz.,
1. Minimal.
Udders washed with plain warm water.
2. Partial.
(a) Hand and udder washing with disinfectant solution; individual cloths or paper towels (chlorhexidine 100 ppm or losan 100 ppm 12).
(b) Teat dipping, immediately after milking (chlorhexidine 5000 ppm or losan 5000 ppm 12).
3. Full hygiene.
(a) Washing as above.
(b) Pasteurisation of teat cups with circulating hot water at 85°C.
(c) Teat dipping as above.
In all herds under trial machine faults were corrected and clinical flareups treated as they occurred. Pasteurisation is the most expensive feature hence its elimination in one trial for comparison. NOTE: Although full hygiene appeared to give the best results both hygiene procedures reduced the new infection rate by over 50 per cent. Teat dipping routine cost $2 per cow p.a. The incidence of clinical flare-ups was 40 per cent less on the hygiene systems compared with the controls. The partial hygiene system can be recommended as a practical routine which at least halves the new infection rate. It has no effect on existing infections and should be combined with an adequate drying off routine.
THE DRY PERIOD
Cows should not be dried off and waved goodbye.
Reasons
1. Clinical Mastitis.
There is a rise in incidence at this time.
2. New Infections.
In the herd with all except a very high standard of skin hygiene the teat skin is infected and so are a proportion of test orifices. As many as one third of all new staphylococcal infections take place soon, after drying off. The first 14 days probably the most important.
3. Treatment.
Drying off affords the opportunity for strategic antibiotic treatment with two aims:
(1) Therapeutic on existing infections;
(2) Preventive therapy at this critical stage by providing a reservoir of antibiotic in the gland.
THE EFFECT OF TEAT DISINFECTION ON NEW INFECTION RATE IN DRY COWS
| No. becoming infected with | ||||
|---|---|---|---|---|
| Treatment | No. quarters examined | Staph. | Str. uberis | Others |
| None = control | 141 | 22 | 28 | 6 |
| Teats dipped after last milking in 5 per cent Tincture of Iodine | 138 | 4 | 31 | 1 |
| Oliver, Dodd and Neave (1956) J. Dairy Res. 23:212. | ||||
Although the administration of antibiotics at drying off is often referred to and many farmers are aware that it is a time to treat a troublesome quarter, there is a dearth of factual information on just what drug(s), formulation, concentration, etc., should be used.
Smith, Neave, Dodd and Brander (1966, Vet. Rec. 79:233), have investigated one of the newer penicillins, cloxacillin ("Orbenin", Beecham Laboratories) which is effective against penicillinase producing Staphylococci. Controls had no teat dip at drying off nor cloxacillin. Test groups were teat dipped (5 per cent available chlorine) and treated with cloxacillin in a slow release base. Sample results for Staphylococci were as follows:
| Exptal Treatment | No. cows | Qs infected at drying off | Infection persisting to calving | New infections | Total infection at C. |
|---|---|---|---|---|---|
| Control 1 gram benzathine salt | 150 | 65 | 61 i.e. 94% | 35 i.e. 6% | 96 i.e. 16% | cloxacillin plus teat dip | 150 | 61 | 11 i.e. 18% | 1 i.e. 0.2% | 12 i.e. 2% |
AN APPROACH TO HERD PROBLEMS
Presentation of problem might be:
1. Post-partum flare-ups. (Thirty per cent of all acute cases can be expected within one month of calving.)
2. Multiple lactation flare-ups. E.g., in Compton herds (Edwards and Smith 1966, J. Comp. Path. 76:231) 34 per cent of cows had subclinical mastitis. The conversion rate to clinical manifestation varied between 1 in 8 to 1 in 4 of these. A high conversion rate suggests an exacerbating factor(s).
3.Sediment problems. Yellow colour on milk sediment pads is generally due to high cell counts (Choi and Forster, 1966, J. Milk and Food Technol. 29:53).
4. Rejection at factory.
STEPS:
1. Assess general state of affairs.
2. The farmer gets the machine checked. You insist on this: vacuum, pump, milk pipeline size, airholes, inflations, etc.
3. You monitor the cows:
(a) RMT herd (may be available from Milk Board officer).
Categorise results (see table).
(b) Examine udders.
4. The farmer applies hygiene clamp on herd. You
supervise.
No hand stripping.
No udder cloths.
Running water if possible.
Teat dipping.
Check milking technique: Is let-down good? Milking time is frequently too long. Are cows overmilked?
5. Bacteriology: If available categorise (see table). If whole herd is not cultured you might be able to get RMT 2 and 3 samples done, e.g., may be simple agalactiae problem in which case the procedure is straightforward.
6. Your assessment of cows leads to a sensible CULLING LIST. This is often one of the most valuable things which can be given the farmer. Culling is often the only way to crack some problems in order to get rid of cows in repeated trouble and at the same time reduce exposure of younger cows — but first check production of individual cows.
7. You provide a milking order schedule.
8. Endeavour to get DRY PERIOD SCHEDULE instituted aimed at eradicating existing infection and preventing new infections in the dry period.
REFERENCES
Brookbanks (1965) New Zealand Veterinary Journal 31:165
He is using:
(1) Running water and hexachlorophene soap;
(2) Back flushing of milking cups with a jet of hot water.
(3) Iodophor teat dip.
Barnum (1962) Canad. Vet. J. 3:161
Good general article.
Vet. Rec., (1965) 77:612 Report of Technical CommitteeNyhan and Coihig. (1967), Vet. Rec. 81:122 - (on vacuum reserve).