On previous occasions at your Annual Conference, and in your Journal, the writer has presented a review of the newer drugs and discussed their modes of action and their uses. To-day, however, it would be preferred to mention a number of diseases in which new methods of treatment are available. Diseases of poultry and sheep will be omitted because, apart from the use of enheptin in the treatment of blackhead in turkeys, no major innovations have been made.
This is not a new method but its revival, particularly in America, has been attended by considerable success. Cases of traumatic reticulo-peritonitis are always difficult to diagnose definitely because of the great variation in symptoms from cow to cow. The unfortunate result is a high mortality rate due to reluctance on the part of veterinarians to employ the major surgical procedure of rumenotomy. A method such as the inclined plane allows one to treat every animal which is suspected to have foreign body perforation of the reticulum. The results obtained are as good or better than with rumenotomy with the possible exception of cases occurring in the last two months of pregnancy. These cases should be operated on forthwith.
A successful technique for the inclined plane necessitates restraining the cow in a bail or confined space in a shed for two weeks. The cow is tied or put in a head bail and a sloping platform placed under the front feet so that they are 8-12 inches above the shed floor. The animal is not allowed to move from this platform at any time for two weeks and full doses of sulfanilamide or sulfamezathine (depending on the value of the cow) are given for five days. If a response is to be obtained there will be considerable improvement in the cow's condition at the end of the third day.
Any explanation of the success of the method lacks experimental proof, but the suggestion advanced is that immobilisation of the cow prevents further penetration by the foreign body. This is assisted by the removal of the pressure exerted on the diaphragm by the viscera. A fibrous wall is built up around the foreign body which later corrodes and disappears.
A further advantage of the method is that early acute cases are left alone for several days to permit adhesions to form. Removal of the foreign body in the early stages may result in death from acute diffuse peritonitis.
Of course, the major advance to be made in this disease is prevention by making farmers fully aware of the dangers of leaving metallic objects in feeding places; and by the introduction of string balers.
One of the most troublesome surgical problems is the treatment of lacerations penetrating to the teat sinus in the milking cow. Provided the injury is seen within twelve hours immediate repair is possible and Michel clips, using size 14mm. clips, offers the quickest and most practical method of effecting repair. No anesthesia and little restraint are required. The teat is dunked in a cupful of 0.5 lysol solution (one teaspoon to the pint) and the clips are then put in so close as to be touching and the teat covered with sticking plaster. Milking it best done with a siphon for the first three days, followed by careful hand milking for another four days. Hand milking can be used from the beginning if care is taken to avoid undue pressure on the suture line. Prophylactic mastitis treatment is essential in every case.
If the injury is of more than a few hours duration twice daily soaking in a cupful of disinfectant solution until inflammation has ceased is recommended. Suturing should not be attempted until the cow is dry.
Because of the difficulty in finding the puncture wound and performing satisfactory excision of the infected focus in many cases of equine tetanus, attempt should be made to destroy the tetanus organism by the use of penicillin. In addition to antitoxin and sedatives, administer three million units of procaine penicillin in water intramuscularly every forty-eight hours. An improvement on this method is to use fortified procaine penicillin which contains, in addition, crystalline penicillin to achieve rapid, effective blood levels.
Most cases of infectious keratitis in cattle recover with no treatment, but occasional cases do become severe due to the formation of a corneal ulcer and under-running of the conjuctlva with yellow pus. Such eyes may take three months to heal and in most cases corneal scarring causes partial blindness. If the disease is due to a rickettsial infection Chloromycetin should be an effective treatment. One English worker reports good results with 0.25% Chloromycetin eye lotion or 0.5% eye ointment applied three times daily.
Molasses gives varying results as a follow-up treatment to glucose intravenously in cases of digestive acetonemia. This probably is due to the variety of aetiological conditions which may cause acetonemia. Glycerine (1lb. twice a day in the feed or as drench for several days) has been reported as a successful treatment. The obvious explanation for the value of glycerine in this condition is that it is metabolised as sugar, but one would not expect it to be more effective than molasses. On the other hand it may be involved in short-chain fatty acid metabolism and be of additional value for this reason.
Highly polymerised methyl silicone introduced through the flank into the abdomen has been found to be effective in breaking down the frothiness in bad cases of ruminal tympany. The mode of action is the same as for turpentine, which increases the surface tension of the rumen fluid.
The treatment of streptococcal mastitis is still primarily by the use of penicillin, although the dose rates used have been increased considerably. The most satisfactory standard is 100,000 units of crystalline penicillin per day for three days. No advantage is apparent in using procaine penicillin.
Staphlococcal mastitis is still a problem and penicillin is of little real value. Aureomycin has been recommended (200-400 mgm. on alternate days for three days) but gives only fifty per cent. recovery. The drug must be administered in a special buffered vehicle as it is itself quite irritant. The difficulty appears to be in getting the drug to the site of infection and almost certainly the only rational treatment will be by the parenteral administration of penicillin.
Streptomycin is now available and gives very good results in the treatment of mastitis due to E. coli. Infection of the udder with Pseudomonas spp. is less amenable to treatment. When using the powdered drug, ½ to 1g. should be infused in water every day for three days. A commercial preparation in tubes containing smaller dose rates is available.
One of the problems in the treatment of mastitis is the necessity for an overall treatment which will be effective against most common infections. This is necessary because of the difficulty of deciding the type of infection by clinical examination and the impossibility of waiting for a bacteriological report.
The most satisfactory general treatment Is a watery infusion of: 100,000 units crystalline penicillin. 1/5 gram. Streptomycin, 20 mls. Distilled Water, administered once daily for three days. This requires three visits by the veterinarian.
Mixtures of lanolin and mineral oil are suitable vehicles for administration of this infusion and maintain suitable levels in the udder for forty-eight hours; necessitating only two treatments.
On many occasions blood transfusions will be of value, but are seldom given. In coccidiosis, haematuria, haemoglobinuria, accidental haemorrhage and neo-natal infections the administration of whole blood has definite therapeutic advantages. The simplest and most satisfactory method is to collect by an open method with a large bore bleeding needle and choke rope, into a 500 ml. bottle containing 2 g. of sodium citrate. Gentle shaking during collection is advisable and a pint can be collected quite easily before clotting of the needle occurs. Administration is simple and a flutter valve apparatus is the most satisfactory. One to two pints usually are used, depending on the size of the animal and the estimated blood loss.
With the introduction of new antibiotics and further trials with known drugs the recommendations with antibiotics vary widely. Below are suggestions as to the best drugs to use in specific infections.
|Corynebacteria||1 (plus anti-toxin)||–||–||–|
|Mycobacteria||–||1 (plus PAS)||–||–|
|Gram negative bacilli||–||2||1||1|
|Pasteurella||–||– (plus SD)||–||–|
|Brucella||–||2 (plus SD)||1||1|
|Fungi||1 (plus SD)||–||–||–|
1 = Best Choice
2 = Second Choice
— = No value or unknown
PAS = para-amino-salicylic acid
SD = sulfadiazine or sulphamezathine
Considerations of cost and availability no doubt will govern the use of these drugs for some considerable time.