§ 6.42 p.m.
§ VISCOUNT HUDSON rose to ask Her Majesty's Government what steps are being taken to counter the menace of vibrio foetus in the dairy herds of this country. The noble viscount said: My Lords, with your Lordships' permission I should like to say a few words on the Question which stands in my name on the Order Paper. I should like also to apologise to your Lordships for reading my speech, a thing which I do not normally do, but, as it is rather a technical point, I hope I may be excused on this occasion.
§ Abortion has long been a source of serious loss to the British dairy farmer. During the war, thanks to the co-operation of the United States Department of Agriculture, we were enabled to introduce what is known as Strain 19 vaccination. The result has been virtual elimination of contagious abortion in our herds. This has disclosed the existence on a scale formerly unrecognised of another cause of abortion, namely, vibrio foetus. The latter has undoubtedly for years been masked by the former. This disease is widespread not only in this country, but also in the U.S.A. and particularly in Holland. Up till very recently, a matter of months. diagnosis has been exceptionally difficult. Ever now, as a result of recent researches, it is difficult in the case of a cow, and in the case of a bull can only be diagnosed by putting a bull on an unspecified number of maiden heifers, at the best of times an expensive proceeding. It is believed that a cow can be cured, but in any case after a certain time she develops a natural immunity. As far as we know at present, there is no cure for a bull. Again, as far as we know, the bull is the only spreader of the disease. This places the ordinary farmer, and especially the pedigree breeder, in a great difficulty. The ordinary farmer has been in the habit of lending his bull for service to the females of his neighbours. Clearly he must be warned to stop this practice because of its dan- 183 gers, and that is one of the objects of this Question, and will be, I hope, of Lord Carrington's answer.
§ The pedigree breeder is particularly affected. It has hitherto been accepted theory and practice that a young bull should be tried out on a certain number of cows and heifers and then put away till the results of his progeny are known. If he is of exceptional parentage, it has been the accepted and good practice to lend him either to a neighbouring farmer or to another breeder to use till such time as he was required back in the herd a his original breeder or owner. There is no doubt that this accepted good practice has in fact led to the wide spread of vibrio in some of the best pedigree herds in the country, and clearly it should cease, with the corresponding serious effect on the production and subsequent spread of the blood of proven sires. Personally, I think that is a tragedy.
§ There is a third possible source of spread of this disease, and that is through artificial insemination at both Milk Marketing Board and non-Milk Marketing Board centres. Proof of this is very difficult to obtain, but it is reasonably certain that centres pursuing the accepted good practice of acquiring proven sires have in some instances acquired bulls infected with vibrio, and have in consequence helped to spread it among clean herds. No possible blame can be attached to those centres, and it is probable that any spread of the disease by artificial insemination is infinitely less than would have occurred naturally had artificial insemination not existed. I think it is only fair to the Milk Marketing Board and other centres to make this plain.
§ We are, however, faced with a difficulty. The Milk Marketing Board believe that they have evolved a technique of buffering their bulls' semen with a triple set of antibiotics, which they believe effectively kills the vibrio in the semen, thus rendering it safe to use even on clean herds. I believe that the Ministry vets entertain grave doubts about the efficacy of this treatment. It is, I believe, accepted that the technique adopted by the Milk Marketing Board until recently—namely, double buffering—was ineffective in rendering an infected bull's semen safe. What is, I submit to your Lordships, important is that a final 184 and authoritative verdict on the efficacy of the triple buffering should be reached at an early date, and I hope the noble Lord, Lord Carrington, will be able to reassure us on this point. Meanwhile, the farming or, at all events, the dairy farming community of the country should be emphatically warned against the dangers of using other people's bulls, or bulls that have been used on other people's cows. They would also be well advised to get their "vets" to make an early investigation into the venereal health of their own herds.
§ 6.48 p.m.
§ LORD CARRINGTONMy Lords, I am grateful to the noble Viscount, Lord Hudson, for drawing attention to this problem. I can say at once that we agree with what he has said. The importance of vibrio foetus infection has, as he said, come to light only comparatively recently, as other diseases causing, infertility have been brought under control. As long ago as 1913, workers in this country had set up abortion experimentally with the vibrio foetus organism, but the view was held then, and for some time afterwards, that the infection was not very important. My noble friend has spoken of the way in which the use of S.19 vaccine has reduced the incidence of contagious abortion. Trichomonas infection has also been recognised as an important cause of abortion and infertility in certain herds. Here again, research has led the way to suitable methods of control. The use of artificial insemination, combined with the treatment of the female, makes it possible to control this disease and the resultant infertility. The application of effective control measures against these two diseases, and the consequent reduction of the incidence of abortion and infertility caused by them, has resulted in the unmasking of vibrio foetus as another cause of infertility, the importance of which was hitherto largely unsuspected.
Intensive research into this disease is being carried on at the Ministry of Agriculture's Veterinary Laboratory and elsewhere, and the results of these investigations into the nature of the disease and methods of control have been, and will continue to be, published for the information of practising veterinary surgeons. In addition, the services of the Ministry's specialist officers are freely 185 available to veterinary surgeons who encounter infertility problems which may be due to vibrio foetus.
My noble friend has rightly drawn attention to the great risk which attaches to hiring or lending bulls for service in other herds. It is well known that in many cases infection has been introduced into a herd by an infected bull, or by an infected female which infects the stock bull when first served by him. The only advice which can be given, in the absence of a specific test for infection in the male, is to maintain a herd as a self-contained breeding unit, or to introduce only maiden heifers or bulls which have never served. If other animals roust be bought they should be bought from a herd only after a full inquiry has been made into its breeding history, in the same way as is practised in selecting bulls for artificial insemination centres.
In view of the possibility that vibrio foetus infection may be spread by infected semen, stringent measures are taken by the Department to ensure that an infected bull is not approved for use at an artificial insemination centre. Although there is no direct test for vibrio foetus infection in the bull, and the organism can only rarely be recovered from an infected animal, every possible precaution is taken to ensure that an infected bull is not approved for artificial insemination purposes. Inquiries are made into the service records of the bull, and the breeding history of the herd in which he is located, and if necessary the history of any herds in which he has previously been. Material from females in the herd or herds concerned is also examined when necessary, special attention being paid to any maiden heifers which may have been served. If, as a result of these inquiries and examinations, any suspicion of infection attaches to the bull, it is not approved for artificial insemination. In addition, the breeding records of bulls at artificial insemination centres are watched closely. If there is a noticeable fall in the conception rate of a particular bull, a special examination is carried out. In all suspicious cases the bull is removed.
My noble friend mentioned the Milk Marketing Board's method of triple buffering of semen. This is said to be a useful adjunct to control, but my Department regard it only as a second 186 line of defence. While there is no experimental proof that this method of treating semen is effective in all cases, the evidence in the held does not indicate that infection is spread from artificial insemination centres to any extent. On the contrary, artificial insemination is a very useful method of limiting the spread of venereal infections.