Brucellosis in Swine

Brucellosis is spread and perpetuated in swine mainly through the infected boar and aborting sow. Recently it has been proved that the causal germ, Brucella suis, is sometimes eliminated in the urine of infected sows, and thus further contaminates the premises. Under such conditions -the most practical method is to dispose of the entire herd, especially if it is small or not too carefully developed, and make a new start in clean quarters.

Replacement animals should be most carefully selected from herds considered to be free from infection. All animals purchased should be negative in all dilutions to the blood test. If valuable blood lines are involved, or if the herd is large, success in developing a clean herd has resulted from separating weanling pigs negative to the blood test and rearing them in clean quarters as far away as possible from the infected herd. This method should be followed in each farrowing season, with the extra precaution that the separated pigs are tested at intervals of several months until bred. When a clean herd has thus been established, the infected herd should be disposed of and the old premises thoroughly disinfected. Herd boars should be selected with utmost care to avoid reinfection of the herd.

Other methods of control, including vaccination, have not proved practical. The infectiousness for man of the germ causing brucellosis in swine is another urgent reason for eradicating the disease.

Brucellosis in Goats

Except in some herds in the Southwest, goats are quite free from brucellosis. During the war, when all sources of food supplies were being utilized, cheese made from goats' milk in the infected sections was believed to have been the cause of several cases of brucellosis in man. Because of the extreme infectiousness for man of the type of brucella affecting goats (Brucella melitensis), all goats producing milk for human consumption should be blood tested. The immediate slaughter of all goats reacting to the test is the only method of control that should even be considered.

Mastitis of Cattle

Mastitis is undoubtedly the greatest scourge in the dairy industry. Each acute attack causes the loss of milk from the infected quarter until the condition improves, the graduated destruction of milk-secreting tissues and, thus, continued lower production during a lactating period until it no longer pays to keep the animal. Estimates are that at least a fourth of all dairy cattle in the United States have mastitis.

Until recently there has been no recognized cure for chronic mastitis. Control measures were of a practical nature—disposing of animals with badly diseased udders, segregating infected cows that were still milking profitably, and preventing the spread of infection to clean cows through strict sanitation in milking and handling the herd.

A few years ago drugs were developed that proved to be effective in curing many cases or a high percentage of cases of mastitis caused by Streptococcus agalactiae, the most common cause. The outstanding drugs are sulfanilamide, colloidal silver oxide, tyrothricin, and penicillin—They are infused into the udder through the teat canal.

Penicillin, the least irritating of the drugs, will cure a large proportion of streptococcal infections if infused daily in proper dosage for 4 or 5 days. Unfortunately, the drugs are much less effective against other types of infection, and are not easy to use. Samples of milk from the quarters of each cow's udder should be submitted for laboratory examination to determine which animals are infected and the type of infection. Each quarter showing the presence of germs should be treated by infusing it with a suspension of the drug selected. After treatment, further checks on the milk should be made as a basis for the disposition of the animals.

The control of mastitis calls for expert advice in herd management, sanitation, treatment, and disposition of affected animals, and should, therefore, be placed in the hands of a qualified practitioner. Drug therapy, even though effective, is only a helping factor in the control of mastitis; no dairyman should consider it as a substitute for proper sanitary practices and management. We suggest gentle, rapid milking, either by hand or machine; avoiding rough hand milking or improper regulation of the milking machine, which may cause irritation of the inner lining of the teat and afford a favorable atrium for infection; preventing injuries to teats and udder by providing clean, roomy, comfortable stalls; removing obstructions, such as high door sills and jagged stumps, which may injure teats and udders.