A way with warbles (1955)

[Music] every year 70 out of a 100 cattle in Britain are infested with the grubs of the warble fly the financial losses caused are heavy infested animals lose condition and their food intake is lowered this situation should not be allowed to continue There are methods of control and experience has proved them to be efficient but it requires a combined effort on the part of all concerned with stock rearing for these treatments to be entirely successful the obvious signs of warble infestation are the appearance of lumps on the backs of cattle in the spring These Lumps show that warble grubs are present under the skin and this is the only stage in the 12- month life cycle when this pest can be readily located by the farmer damage to the back is considerable less than one hide in 10 is suitable for the production of high quality leather when the grubs emerge the skin may be left in this condition this hide has been put through the slow elaborate process of tanning but is of no practical use because of warble damage warble flies are about half an inch in length and resemble the wild bee their mouth Parts never form properly and they are unable to bite sting or feed Wing development is poor and long sustained flights are unusual their spread is encouraged by the movement of INF Ed cattle from place to place during their short life of about 7 Days warble flies have one main biological function to perpetuate their kind from early June to September successive waves of female flies are engaged in finding grazing cattle on which to lay their eggs these are laid mainly on the lower parts of the legs and perhaps on the unders surface of the body but no area of the animal is completely free from risk of attack these are eggs La by one of the two species of warble fly found in Great Britain the eggs are glued to the hair and remain in position for about 1 week when the minute lari hatch and penetrate into the body the precise movements of the ly are not known but from February to mid-march they begin to arrive under the skin of the back on reaching this point they cut breathing holes through the skin the beneath these holes they lie for about 10 weeks steadily growing in size the irritation caused during this period is responsible for loss of condition in badly infested cattle while from 5 to 30 holes are common in a wobbled animal in severe cases more than 100 have been found it is reasonable to suppose that stock breeders are concerned with making the best possible Living For themselves if animals are neglected and not given the attention they should have the owner must be prepared for the eventual loss to be hits although not usual some animals May Reach This distressing condition on reaching maturity the lava or grub forces itself out through the hole in the skin and falls to the ground during the latter half of March throughout April May and early June there is a steady succession of these grubs leaving the hosts they have thrived on for so long the life cycle is now nearly complete the Earthbound grub instinctively seeks the protective cover of any loose material gradually it shrivels hardens and sinks into the coma of pupation the pupil stage of the life cycle is relatively short in a matter of about 6 weeks the fly emerges and becomes potentially dangerous to cattle a very short time afterwards in about an hour or so after the fly leaves its pupil case mating takes place one in is sufficient to fertilize the 3 to 400 eggs carried by each female the life cycle is now complete and we are back to the earlier situation of fertilized warble flies about to seek out grazing cattle during the warm summer months the Unseen and unsuspected damage begins it is not until the following spring that the physical evidence of the fly's activity is brought so forcibly to the farmer's notice until recent times only one method of control was available scrubbing the back of each infested animal with a deis wash this had to be done in the spring when the lumps indicated the presence of grubs lying beneath the breathing holes unfortunately there was no alternative to this treatment which was laborious and could involve scrubbing animals several times at a very busy period of the year at this stage also the hide may be so full of holes as to make it useless to the leather trade destruction of the almost mature grub by squeezing it out is dangerous and may be the cause of unnecessary suffering because of the inconvenience of dery stressing many other methods of getting rid of the warble fly have been tried attempts have been made to prevent the eggs hatching while on the hair or to kill the young grubs before they penetrate the skin mainly because of the labor involved these efforts of control were found impracticable logically the most satisfactory method of control is to kill the migrating lvi while they are still within the body of the host preferably at an early stage in their development before they damage the animal as a result of research which has been carried out over a number of years there are now available highly efficient chemical compound compounds which do this these materials are known as systemic insecticides and are so named because when they are brought into contact with the animal they are rapidly absorbed through the skin into the bloodstream and then circulate to every part of the animal system the liquid is simply poured along the animal's back with this once-yearly treatment the beef farmer is relieved of the trouble of repeated handling of outg grazing cattle when used purely to attack the migrating larv within the animal systemic treatment should be carried out during October and November it is also possible to apply the systemic between March and June the time of year when deris was normally used and again one treatment is all that is necessary of course skin damage will have occurred by then but the soon the dressing is carried out the less this damage will be when used in the spring the liquid acts both as a systemic and as a contact dressing it has also been found that systemics provide a limited measure of Lous control there cows do not present the same labor problems as they are in and out of the buildings every day cows in milk can be dressed with systemics provided the longest possible time is allowed between treatment and the next milking systemic treatment of cattle has been proved effective and it is the policy of the Ministry of Agriculture to encourage Farmers to treat their cattle the modern way this simple method means that a big step has been taken towards Eric a of the warble fly the hard work of scrubbing has been eliminated the job can be done at a quieter time of the year handling of cattle has been much reduced cattle without warbles do better and give more milk than infested animals it is now up to the farmer to improve his stock by cooperating with the ministry in putting an end to the wble fly [Music]