Until recent years there has been known no satisfactory treatment for Mastitis of cattle. Various therapeutic measures were recommended from time to time, but none proved satisfactory and we were compelled to depend upon general measures such as massage, foments and frequent stripping. The best we could hope was that the intensity of the inflammation would be relieved and the quarter would produce milk again. We had no method of attacking the bacteria in the udder and no means of preventing the development of fibrotic areas in the udder tissue. Vaccines were used fairly extensively because although in other countries they were classed as useless by various authorities we found that they did have some effect in reducing the incidence of acute mastitis.
With the discovery of the germicidal value of the flavine derivations, European veterinarians tested their value for Mastitis treatment by injections into the udder. Many flavine preparations were tested and that which eventually found most favour was Entozon. Stewart tested this in the herd of a Government Institution. He found that in 70% of cases the udder was freed of Streptococci—as judged by cultural examination of milk at varying periods after the solution was injected—although in some cases two or three successive treatments were necessary before this result was obtained. About 30% of cases of Streptococcal infection resisted the treatment, which also did not give great satisfaction in the therapy of Staphylococcal Mastitis. The discovery of this treatment was a great advance on previous knowledge and just prior to the outbreak of war a number of dairy farmers were using Entozon with considerable success. As with all such treatments some did not get good results because they failed to carry out the instructions of the makers and did not observe the principles of cleanliness. The outbreak of war and the diversion of factories to the manufacture of war materials cut off the supply of Entozon. Some authors had recommended the use of Acriflavine in place of Entozon. In Stewart's experiments this dye was much more irritant than Entozon and not as effective. European workers have reported better results than those obtained at Glenfield. They claim that the treatment of dry cattle is more effective than treament during lactation.
The successful use of Entozon by udder infusion, however, stimulated investigations with other preparations. Sulphanilamide and related drugs had meanwhile become recognised as valuable aids in the treatment of microbial disease and it was obvious that its value in Mastitis would be tested. Excellent results were reported in America from the intra-mammary injection of Sulphanilamide suspended in liquid paraffin. As Sulphanilamide is being made in Australia, although most of the supplies go to the Army, it was tested. In some cases the results of treatment were reported as "dramatic" and generally it appeared to be more efficient than Entozon.
We had our doubts about injecting 40 c.c. of the suspension into the udder of cows, the milk of which was used for cream production. It seemed likely that the paraffin would not be absorbed and that its presence in the cream obtained from the subsequent milking might reduce its quality. In a small test we were unable to make butter from the cream of a cow which sixteen hours before had been subjected to this treatment. This aspect of the matter is still being examined. Meanwhile, we are treating a herd with Sulphanilamide in water. We have found that no matter how the Sulphanilamide is suspended or what suspending fluid is used, the drug tends to agglommerate into masses and will thus clog the syringe or teat syphon. Thus, all suspensions must be freshly prepared before use. Other objections are that four successive daily treatments are required and the cost of the drug is high. However, it is so effective that we are continuing our experiments in the hope of finding a method of use that will make the Sulphanilamide treatment suitable for routine use.
Another drug that has received much publicity is Gramicidin, which is prepared from a soil bacillus and which has been found to be of value in the treatment of infections caused by gram positive micro-organisms. This has been tested in America and reported to have given results at least equal to those of Sulphanilamide. Supplies of Gramicidin are unlikely to be available in any quantity in Australia until after the war and possibly the price factor may prevent extensive use. Recently we managed to obtain sufficient to treat about thirty cows and a report on the results will be furnished later.
Colloidal silver oxide—Novoxyl—in mineral oil, as an injection into the udder, has been reported upon favourably in America, but one investigator has stated that the injection of Novoxyl into the normal udder was irritant. Another treament, that of the injection of iodised mineral oil, has also been stated to give good results. We have no experience with either of these methods.
While, therefore, the outlook for the development of an effective method of Mastitis therapy by the infusion of fluids containing germicides is very promising, it is unfortunate that at the moment the probability of suitable drugs for this purpose being made available for general use is remote.