VETERINARY NOTES

New Zealand Journal of Agriculture, Volume 70, Issue 4, 16 April 1945, Page 413

VETERINARY NOTES

Gastro-Intestinal Parasites in Calves

CONSIDERABLE losses are experienced annually in New Zealand through the ravages of gastro-intes-tinal parasites in calves. Seasonal conditions experienced this year are such that perhaps more than average trouble may be experienced. Control measures properly applied can save the farmer considerable financial loss and worry. The wormy calf appears stunted, emaciated, anaemic, hidebound, the coat is harsh and dry, and persistent scouring is present. In severe cases death may intervene, generally in the late autumn or winter. Even if severely-infested animals survive, their constitution is seriously undermined. In fact, the wormy calf of today is the unprofitable cow of tomorrow. Internal parasites of calves may be broadly divided into two groups, those which inhabit the lungs and those found in the fourth stomach or abomasum and intestines. The latter group are the more important. Indeed, the view is widely held that lungworm infestation is of importance only when a heavy infestation of gastro-intestinal parasites is also present, and that control of the latter effectively keeps the former in check.

The scientific names of the various worms matter little to the farmer. There are numerous species, and it is generally found that the infested calf harbours several types of worms at once. The worms are small and threadlike, some being small enough to escape naked eye observation. The untrained observer can easily overlook the presence of a heavy infestation on post-mortem. Laboratory examination of stomach and bowels for worms or of dung for worm eggs quickly gives an indication of the extent of the infestation. Under favourable conditions worm larvae can exist for long periods on the grass. With regular rainfall, lush growth, and heavy carrying capacity, New Zealand conditions are ideal for heavy worm infestation. Calves may become infested at an early age, and the infestation is built up during the summer and autumn. Obvious symptoms do not generally become apparent until late summer, and, unless control measures are applied, affected animals become progressively worse during the late summer and autumn. Faulty nutrition or mineral deficiency are factors which may complicate worm infestation, and should be corrected at the outset.

Control of parasites depends first on regular drenching to rid the host of parasites, and second on rotational grazing to prevent re-infestation. The introduction of phenothiazine has been a big step forward in the battle against parasites. There is no doubt that this drug is easily the most efficient for the purpose at the present time. It is somewhat expensive, and administration is not as easy as, say, with bluestone-nicotine, but the results are so good that these points can be overlooked. The dose of phenothiazine is from J to one ounce of the powder either in a drench or mixed with the feed. Bluestone alone is still widely used. The results, while not as good as with phenothiazine, are generally satisfactory, and the farmer who has had good results from this treatment is justified in carrying on with it. Dose rate: Dissolve Boz. of bluestone in 3 gallons of water. Dose for 4 months old calf 30z., 6 months 40z., 9 months 60z., 12 months Boz. Tetrachlorethylene in liquid paraffin has been used to some extent, but it is doubtful if the results compare with the bluestone solution, and it is more expensive and more dangerous to administer. It is doubtful if there is anything to recommend the use of turpentine or other non-specific agents to control worms in calves. Their efficiency certainly would not compare with that of any of the above treatments.

The secrets of ' effective drenching are: 1. To drench early before calves , show symptoms of worm infestation. 2. To drench regularly so that worms are dealt with as soon as they mature. Three-weekly drenching is necessary in many cases to keep the worms in check. The value of rotational grazing cannot be overestimated in the fight against parasites. It is probably impossible to prevent re-infestation taking place, but a change of paddock after each drench is the nearest approach to ideal. It is well known that parasitism is much more prevalent on heavy, rich country than on poorer light country. In the first case, stocking is heavier, contamination of the . pasture is heavier, and as a result, each calf gets a heavier infestation. Supplementary feeding with concentrates has much to recommend it in keeping up the resistance and general health of the calf. Again, if supplementary feeding is to be resorted to, do not wait until obvious symptoms of parasitism are present. To sum up, the farmer who has trouble with internal parasites of calves should: — 1. Build up the resistance of the animals by a high standard of nutrition. 2. Drench early and regularly, using a reliable vermifuge. 3. Provide rotational grazing to prevent re-infestation of the calves. Such a programme should be easier and cheaper than burying his own calves and buying replacements. —R. P. GILDER, B.V.Sc., Veterinarian, , ' Palmerston North.

Answers to Correspondents Windsucking Mare “J.G.” Wedderburn:— I have a thoroughbred mare which is a bad windsucker and would be pleased if you could let me know it there is any cure for this complaint. The mare has been affected for a period of about 12 months. LIVESTOCK DIVISION:— Windsucking is a vice which, if allowed to continue, may have a serious effect on the health of the horse, and thus lead to unsoundness. It is very similar to crib-biting, except that a grip is taken on thin air instead of some part of the manger or fittings. In order to windsuck, the horse must extend the neck, thus tensing the muscles of the neck and jaws. When well-established it may be found impossible to break the habit, in which case the animal will gradually become

useless for work.. If, however, the habit is a fairly recent acquisition, it may be possible to cure by preventing the extension of the neck. Feed the animal on the ground, and when turned loose have it controlled by a headstall with a strong strap tied short between the forelegs to a band around the chest, allowing sufficient play for a normal carriage of the head. As windsucking is usually associated with crib-biting, it would be advisable to examine both the manger and the mare’s teeth for evidence of excessive wear. If it is found to be a crib-biter also, you must adopt some means ,to discourage this. Feed on the ground, or smear a solution of bitter aloes over the parts of the manger used by the horse to bite on. If treatment on the lines given above is unsuccessful, there is little else you can do, except get rid of the animal

or keep it apart from others which might copy the vice. Rape as Greenfeed for Milking Cows “V.A.D. ”, Taupiri:— Could you please tell me if rape is good for milking cows as greenfeed. LIVESTOCK DIVISION:— Rape is grown chiefly for sheep or pigs. It is satisfactory for cattle, but dairy cows should be fed rape or grazed on the crop only immediately after, milking, to avoid tainting the milk. To avoid danger from bloat or excessive scouring cows should not be left on the rape for more than half-an-hour. Only mature rape should be fed, maturity being indicated by the change of colour of the leaves from green to slightly purple.