CALIFORNIA AGRICULTURAL EXTENSION SERVICE CIRCULAR 21 AUGUST, 1928 BOVINE TUBERCULOSIS C. M. HARING and J. TRAUM PUBLISHED BY THE COLLEGE OF AGRICULTURE UNIVERSITY OF CALIFORNIA Cooperative Extension work in Agriculture and Home Economics, College of Agriculture, University of California, and United States Department of Agriculture cooperating. Dis- tributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. B. H. Crocheron, Director, California Agricultural Extension Service. UNIVERSITY OF CALIFORNIA PRINTING OFFICE BERKELEY, CALIFORNIA 1928 Digitized by the Internet Archive in 2011 with funding from University of California, Davis Libraries http://www.archive.org/details/bovinetuberculos21hari BOVINE TUBERCULOSIS C. M. HARINGi AND J. TRAUM2 All species of domestic animals are susceptible to tuberculosis, but the disease is more prevalent in cattle, hogs and poultry than in other farm animals. Tuberculosis is readily transmitted from one individual to another of the same species by direct or indirect contact. On the other hand, transmission between species varies because of the existence of three more or less distinct types of tubercle bacilli, the human, the bovine and the avian. In general, tuberculosis found in cattle is induced by the bovine tubercle bacillus. However, local, non-progressive lesions have been produced experimentally in cattle by the human type, and rare cases of small, limited lesions due to natural infection with this type have been found also in this species. Cases of uterine infection of cattle with avian tuberculosis have been reported in Denmark. Tuberculosis in poultry has been found' to be caused by the avian type of tubercle bacillus in 100 per cent of all cases studied. Hogs contract tuberculosis easily when fed on infected milk or when run- ning in fields with tuberculous cattle or poultry. The disease induced in swine by the bovine bacillus is often fatal, but infection with the avian bacillus very seldom becomes progressive in swine, the lesions being limited usually to the lymph nodes of the head and neck. Goats are experimentally very susceptible to the bovine type of tubercle bacillus and, Avithin the past ten years, several advanced cases of tuberculosis in milch goats have been observed by the writers and by others. Sheep and horses are more rarely affected with this disease. The former are susceptible to the bovine type and the latter, while most frequently affected with the bovine bacillus, are also sus- ceptible to the other two types. The bovine type of bacillus rarely causes the lung form of the disease in adult human beings, but it is responsible for certain forms of tuberculosis in infancy and childhood. The percentage of cases of bovine tuberculosis occurring among children depends on local condi- tions, and is variously estimated. The cause of this type of the disease in children is infection transmitted through raw milk and cream. 1 Professor of Veterinary Science and Veterinarian in the Experiment Station. 2 Associate Professor of Veterinary Science and Veterinarian in the Experi- ment Station. 4 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [CiRC. 21 It may also be present in other dairy products, such as unpasteurized butter, fresh cheese, skimmed milk, and buttermilk. For this reason the retailing" of unpasteurized milk from cows that have not passed the tuberculin test is prohibited by law in California.^ THE ECONOMIC ASPECT OF BOVINE TUBERCULOSIS The losses due to the prevalence of this disease in farm animals are not as apparent as they are important. It is no uncommon thing for a veterinarian to find 70 or 80 per cent of the cows in a herd tuberculous without much loss being evident to the owner. Losses from deaths due to tuberculosis seldom become serious in a herd until the disease has spread to a majority of the animals. Often the first intimation that anything is wrong comes to the owner through the report from the abattoir that cattle from his ranch have been con- demned as unfit for food on account of tuberculosis. The proportion of hogs condemned by meat inspectors on account of tuberculosis is an indication of the spread of infection in cattle since the cow is the chief source of tuberculous infection in swine, the disease being transmitted to swine through milk or buttermilk from tuberculous cows, through infected cattle corrals or by feeding uncooked carcasses to the hogs. The enormous losses due to this disease are a tax upon every pint of milk and every pound of beef sold. That the aggregate loss to the state is enormous cannot be doubted, but, on the other hand, the loss to the individual owner is seldom so great as to make him ready to adopt measures involving a great deal of immediate trouble and expense, in order to secure eventual complete freedom from the infection. 3 The California Pure Milk Law (Statutes 1927, Chapter 888) gives the alter- native to either pasteurize the milk and cream sold at retail or to submit the cattle to an official tuberculin test. Dairymen who sell in bulk to the wholesale trade for pasteurization need not have their cows tested or install a pasteurizer. The responsibility of pasteurization rests on the creamery. In cities or counties having an approved dairy inspection service all milk retailed must be graded and properly labeled. Every cow owner who intends to retail any unpasteurized milk or other dairy product, except cheese, should write to The State Department of Agriculture, Sacramento, California, requesting that his cows be tuberculin tested. Those intending to retail in any city or county having a dairy inspection service should file a duplicate request with the local health officer. Pasteurization on the dairy ranch is impracticable in most cases. Any dairy- man who is contemplating the installation of pasteurization equipment is advised to confer with the officials of the State Department of Agriculture or with the chief dairy inspector of the city in which his products are used, for some cities refuse to allow milk to be sold unless it has been pasteurized within the cities. It is, moreover, illegal to repasteurize milk to be sold as market milk for human consumption. 1928] BOVINE TUBERCULOSIS THE SYMPTOMS OF TUBERCULOSIS IN CATTLE There is no symptom that can be relied upon with certainty. A herd may be badly infected and yet none of the cattle show symptoms of ill health. Tuberculosis may attack almost any organ of the body, but until it has progressed to an advanced stage there may be no visible signs. Following are some of the more important symptoms suggestive of the disease, but it should be understood that these may also be caused by other diseases : Unthriftiness. — In advanced stages of the disease the coat may become rough, the hair failing to shed readily with the change of seasons. The skin loses its suppleness and feels harsh and thick and is difficult to fold when grasped by the hands. This is especially noticeable in the neck or flanks. This condition is known as ''hide- bound." The debilitated expression of the eyes and face, the bristling hair, arched back, and tucked-up abdomen are symptoms which may or may not be present in advanced tuberculosis. Loss of Flesh. — A gradual falling away in flesh should always be a cause for suspicion, but leanness is a common characteristic of good dairy cows; therefore a knowledge of the normal for each individual animal is necessary before judgment may be passed on this symptom. Cough. — This symptom is only present when the disease is attack- ing the lungs or some part of the breathing organs. It is usually rather subdued and infrequent and may occur only when the animal is driven or when it gets up after having lain down for some time. Tuberculous cows do not appear to expel anything when coughing. This may be because they cannot spit. Most of the material coughed up from the lungs is swallowed, but many tuberculosis germs escape from the mouth in the spray. Nasal Discharge. — A slight discharge of pus from the nostrils may occur in cattle with advanced tuberculosis of the lungs. This discharge is often removed by the frequent licking of the nostrils and would be overlooked by any but a close observer. Enlarged Glands. — Hard, painless swellings in cattle are apt to be due to tuberculosis. These are especially prone to occur in the region of the throat, in front of the shoulder, or in the flank or groin. Swellings under the jaw proper are more often due to actinomycosis or to the penetration of the tissues by foxtail beards. Tuberculous growths often develop in the throat or back of the jaws so as to produce a hoarseness in breathing. 6 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 21 Hard Lumps in the Udder. — When tuberculosis attacks the udder no change can be detected at first, but after a time hard lumps can be felt in some parts of the organ after it is milked out. Milk from such an udder must not be used. Chronic Bloating. — Sometimes the diseased glands in the chest prevent the usual passage of gas from the paunch to the mouth by pressing on the gullet. The resulting bloat is recurrent or chronic and easily distinguishable from the acute bloating caused by green alfalfa. Diarrhea. — Looseness of the bowels or ''scouring" is seen in advanced stages, particularly when the disease is generalized. This kind of scouring does not yield to treatment. WHAT TUBERCULOSIS IN CATTLE LOOKS LIKE When the carcass of the cow affected with tuberculosis is opened, the disease may be found in any part of the body, but it is usually located in the lymph glands of the chest, throat or abdomen. The exteriors of the tubercles often look like masses of piearls, especially when on the chest or abdominal walls, and on this account years ago the disease was called pearl disease of cattle. Tissues showing lesions of tuberculosis in cattle and hogs may be seen in the veterinary exhib- its of the College of Agriculture at Berkeley. Colored plates, repro- ducing the appearance of tuberculous tissues in cattle, may be seen in the Special Report on Diseases of Cattle, obtainable for one dollar from the Superintendent of Documents, Washington, D. C. A limited number of copies are for free distribution by United States Senators and Representatives. THE CAUSE OF TUBERCULOSIS IN CATTLE Although there is much that is yet to be satisfactorily explained concerning the way in which cattle contract tuberculosis, it is defin- itely known that the disease results from the invasion of the tissues of the body by bacteria.* The bacilli of bovine tuberculosis are 4 The Baccillus tuberculosis (Kocli) belongs to that genus of microscopic plants known as mycobacteria. When the infected tissue is smeared on a glass slide and properly stained the bacteria may be seen by means of a high-power microscope as slender, slightly bent rods, .00006 to .00015 inch in length by .00001 to .00002 inch in diameter. These organisms do not stain readily with ordinary aniline dyes. Once stained with carbobfuchsin, however, the dye is retained even after the application of alcoliol or 80 per cent sulphuric or hydro- chloric acid. For this reason tubercle bacilli and a few other species of bacteria are classed as ''acid and alcohol fast^', as distinguished from those which lose 1928] BOVINE TUBERCULOSIS 7 believed to exist only in the tissues of diseased animals and in their excretions, or on substances contaminated by these excretions. Except under the most favorable conditions they do not multiply outside the body, although if not killed by sunlight or disinfectants they may survive in moist dirt for several months. Tuberculosis in cattle and swine is not hereditary. A few cases are recorded where animals have been born tuberculous, but only when the reproductive organs of the mother were diseased. HOW THE DISEASE SPREADS When an animal first becomes infected there is usually no danger to other animals, but sooner or later tuberculous cattle may begin to have infectious discharges. The germs escaj^e through the mouth and nose, the bowels, the milk, with discharges from the genital organs and from open lesions in any part of the body. When the disease is located in the lungs and discharges into the air tubes, pieces of diseased tissue and millions of germs are liberated and coughed up. Most of these are swallowed and passed out in the manure. This is the chief way in which the tubercle bacilli are discharged from diseased cattle. When the germs are being given off in any of these ways, the disease is known as open tuberculosis. Cattle in advanced stages of the disease usually have open tuberculosis. The high per- centage of tuberculous cattle and hogs on certain ranches has been found to be due to the failure of the owners to remove promptly animals that develop visible indications of the disease. Tubercle bacilli discharged from the mouth and nose are coughed up from the lungs and are sprayed over the food in front of the cow or are carried in the air for a time until they fall to the ground. Cows in adjoining stalls may take in these germs in the air they breath or in the food they eat, and so contract the disease. Germs discharged from the bowels are mixed with the manure and may infect cattle and hogs that are allowed to pick over the dung the color of their stain when treated with alcohol and acid. Tubercle bacilli are not readily obtained in pure culture from tuberculous tissues. The usual method is to inoculate guinea pigs and from their diseased tissues inoculate a large number of tubes containing egg media. When once started to grow on egg media the germs can be transferred and more readily cultivated on glycerine bouillon. Tubercle bacilli of cattle, man and birds may be distinguished from one another by appropriate laboratory methods. The human and bovine types are both fatal for guinea pigs. The human variety is only mildly pathogenic for rabbits or cattle and the tissue changes which it produces in these are slight and usually restricted to the point of inoculation. Tlie bovine variety wlien inoculated into cattle or rabbits is fatal as a rule. 8 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClltC. 21 heap. The practice of having hogs and cattle together in the same yard often results in the infection of the hogs, if any of the cattle are affected. Manure containing tuberculosis germs may easily infect the milk. Particles of manure may fall into the milk pail from the skin of a dirty cow or be accidentally flicked off the tail and fall into the milk. Straining the milk afterwards removes only the larger particles. The smaller ones, including the germs of the disease, remain in the milk. When the udder is tuberculous, the milk contains the germs in vast numbers. Although such milk may look and taste perfectly good, it may transmit the disease. Hogs and calves are readily infected by it. It is also dangerous to children. When all the tuberculous areas in the body are so situated that no tubercle bacilli are being given off or discharged in the secretions, as above described, the condition is known as closed tuberculosis. Such animals do not transmit the infection until they become so diseased that the tuberculous areas open into a passage leading to the exterior of the body. Many infected cattle never develop open tuber- culosis, but there is no way of determining accurately in living cattle which are the open cases and which are closed. In badly infected herds a careful physical examination by a veterinarian will eliminate a certain proportion and a much larger proportion may be detected by the inoculation of guinea pigs. This latter procedure, however, is impracticable under average dairy conditions and it will fail to detect those cases which do not happen to discharge germs at the exact time the sample is taken. Bate of Development. — Individual animals exhibit the widest variation in the duration of the disease. In the majority the disease pursues a leisurely course, consuming years before causing death. Most infected cattle are fattened and sold for beef, but some develop a rapidly fatal type. Its onset is always unobtrusive and its progress is so gradual that its presence does not cause apprehension. Losses are so evenly distributed in point of time that they do not excite serious alarm, as do other less destructive diseases of the pestilential type which kill many suddenly. The rate of spread in a herd is vari- able. In some herds which are known to have a few reacting animals the disease does not seem to spread. Perhaps this is due to the fact that few, if any, of these happen to be open cases. On the other hand, in certain instances under observation the disease has been introduced into clean herds and in a few months, through the development of open cases, a large proportion of the cattle have become reactors. The feeding of infected milk to calves, particularly unheated mixed skim- milk returned from the creamery, usually results in speedy infection. 1928] BOVINE TUBERCULOSIS HOW A HERD IS INFECTED Tuberculosis may be introduced into a healthy herd in a number of ways : 1. By the purchase of a bull or other animal that is infected with the disease. This animal may be apparently healthy at the time of purchase, but if previously exposed the disease may develop and be spread to other cattle. Where a healthy herd is being maintained, animals should only be bought subject to the tuberculin test and even this precaution may fail if the herd from which they come is infected. 2. By feeding calves with milk, buttermilk, or whey that has come from tuberculous cows.^ A farmer may have a healthy herd, but, if he brings home skim-milk from a creamery and feeds it to his calves, the germs, if present in the milk, may be transmitted to them. Such milk should be rendered safe by boiling or pasteurizing. 3. By showing cattle at fairs and exhibitions where proper care is not taken to keep out diseased stock, or to disinfect the stables. 4. By shipping animals in cars that have not been disinfected, as these may have recently carried diseased cattle. 5. By allowing the cattle to graze with diseased ones, or to come into contact with them over fences. 6. When the cattle are permitted access to small ponds, water holes, or troughs, these may become badly contaminated with infec- tion from "open cases". The rapid spread of the disease on certain ranges is believed to be due in part to infected water. 7. Improperly sterilized bone meal used in certain cattle feeds or so-called mineral mixtures has been suggested by some to have occa- sionallv transmitted tuberculosis. HOW THE PRESENCE OF TUBERCULOSIS INFECTION MAY BE DEMONSTRATED The tuberculin reaction is the best method at j^resent available for the recognition of tuberculous infection in cattle. There are several reasons why this special test is necessary. Unless cattle are badly diseased they seldom show symptoms of ill health. Almost any organ of the body may be attacked, but until the abnormal process has progressed far enough to interfere seriously with some function, no symptoms can be detected. The thickness of the skin and chest wall makes it difficult to detect a diseased condition in a cow's lung 5 California Statutes 1921, Chapter 696 requires creameries to pasteurize skim milk and other by-products returned to farms for feeding. 10 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 21 by listening to the sounds made in breathing, whereas this is com- paratively easy in human beings. Next to the tuberculin test, a careful physical examination by a trained veterinarian is the most practicable method of diagnosis ; in fact, the tuberculin test should always be supplemented by such an examination, since badly diseased cattle often do not react to the test. Other methods which occasionally may be useful in detecting the disease are the microscopic examination or the guinea-pig inoculation of diseased tissue, exudates from the pulmonary, intestinal or urinary tracts and pus from abscesses. Animal inoculation with such material is a much more certain test than a direct microscopic examination. TUBERCULIN AND ITS USES Tuberculin is the filtered and sterilized glycerine bouillon upon which tubercle bacilli have grown. It contains no germs and is harm- less to healthy cattle even in increased dosage. All tuberculin entering into interstate trade must be produced in a laboratory under U. S. government inspection. Each bottle must indicate on its label the equivalent strength in terms of Koch's old tuberculin. When the tuberculin is concentrated to 1/lOth of the volume of the original inoculated glycerine bouillon, it is known as Koch's O.T. or old tuber- culin. In tuberculous cattle it produces a temporary effect or reaction. The living tissues of tuberculous persons and animals are hypersen- sitive to tuberculin. This sensitiveness is most marked in the tissues that are actually invaded by the germs, but it also exists to some extent in the other tissues of the body which contain blood vessels. The living tissues of individuals not infected with tuberculosis show no sensitiveness to tuberculin. When tuberculin is injected into the vascular layers of the skin of a tuberculous cow, a swelling will usually follow. When dropped on the eyeball, an exudate of pus may result. When injected under the skin in sufficient amount, a general systemic response occurs which is chiefly manifested by a rise in temperature, usually between the eighth and the twentieth hour after the tuberculin is adminis- tered, lasts a few hours and then subsides. These symptoms are called reactions, and animals which show them are called reactors. The value of the test lies in the fact that a high percentage of tuber- culous animals react, while healthy ones do not. There are several ways of testing with tuberculin. The methods which are most practicable are the intradermie, the subcutaneous and the ophthalmic. Each of these methods has certain advantages. The 1928] BOVINE TUBERCULOSIS 11 conditions under which the testing is to be performed should be the guide in choosing the method. The properly combined use of all three tests on the same animals gives the highest accuracy in diagnosis. Training and experience are necessary for a veterinarian to secure best results. In brief the procedure is as follows : (a) The intradermic test consists of injecting two or three drops of tuberculin into the layers of the skin. The location usually pre- ferred by veterinarians is one of the folds of skin on the under side of the base of the tail. A positive intradermic reaction is indicated by a thickening of the fold. This thickening is usually best observed between 48 and 120 hours after injection. {!)) The subcutaneous test consists in injecting two to four cubic centimeters of diluted tuberculin beneath the skin of the neck or shoulder. The reaction consists in a rise of temperature between 8 and 20 hours after injection, and occasionally by symptoms of depres- sion, shivering, bristling hair, ceased rumination, and looseness of the bowels. (c) The opthalmic test consists in placing under the eyelid a small disc of milk sugar permeated with tuberculin, or applying the concentrated fluid form to the eyeball. The best results are obtained by the sensitized test. This consists of two instillations, two to three days apart. The reaction consists in a mild inflammation of the eye with a discharge of pus, which usually ceases in a few hours. LIMITATIONS OF THE VARIOUS METHODS OF TESTING No form of the tuberculin test destinguishes between severe and slight cases, nor between those that are spreading infection and those that are not inconvenienced by the disease and are not infecting others. The test is searching and even in an extremely slight infection will cause the animal to react. In cattle reacting to the test the infection may occasionally be so recent and the changes so slight that the ordinary methods of postmortem examination fail to demonstrate the presence of tuberculosis, since the lesions may be microscopic in size. If no reaction occurs, care must be taken for there is still a chance that the disease is present. Each form of the test has its special value and limitations. Nevertheless, the tuberculin test is the most accurate and valuable means at hand for the diagnosis of tuberculosis in cattle. Following are some of the factors to be considered : (1) The animal may not react if very extensive tuberculous, but in such cases physical symptoms will usually indicate ill health. 12 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [CiRC. 21 (2) The reaction does not occur during the period of incubation of the disease; in infected herds a second test should, therefore, be made in from sixty to ninety days. (3) Cows that have once reacted may fail to do so upon subse- quent tests, but frequently, in such cases, the disease is known to have become active again after a time. (4) The possibility of the cattle having been ''plugged" (ren- dered insensitive) by the previous injection of tuberculin must be taken into account. The discovery that the ophthalmic test will usually cause reactions in ' ' plugged ' ' tuberculous cattle has somewhat decreased the importance of the chance of error. (5) Sometimes tuberculous animals have been observed to react to one form of test and fail to respond to the others. A proportion of such cases may be due to lack of sufficient care to observe the effects of the tuberculin upon the individual, i.e., failure in the subcutaneous test to take sufficient temperatures; failure in the intradermic test to inspect the point of injection at proper intervals; failure in the ophthalmic test to keep the animals under proper environment and constant observation. CHRONIC LYMPHANGITIS A CONFUSING FACTOR Cattle are sometimes affected with nodular lesions of the skin and subcutaneous tissues in which avirulent, acid-fast bacilli, resem- bling Bacillus tuberculosis, are present. This condition is sometimes called skin tuberculosis. Crawford^ has suggested the term "subcuta- neous tubercular nodule ' ' ; subcutaneous, because the lesions are under the skin ; tubercular in preference to tuberculous since the latter term pertains more strictly to lesions caused by virulent tubercle bacilli. The choice of names for these conditions should not be made until the nature of the various acid-fast organisms found in these nodules is more satisfactorily established. The nodules are visible in the living animal, but may be so small that they do not attract attention. They do not spread to the viscera or internal lymphatics or interfere in any way with the efficiency of the animal. The presence of these nodules may render an animal sensitive to tuberculin. The condition has been found in herds that are free from virulent tuberculosis and it is some- times impossible for a veterinarian, when tuberculin testing a herd where this disease is present, to certify that the herd is free from 6 Crawford, A. B. Studies in so-called ''skin lesion" tuberculosis. Jour. Amer, Vet. Assn., 73:216-222. 1928. 1928] BOVINE TUBERCULOSIS 13 reactors although he may believe that there are no cattle present which harbor virulent tubercle bacilli. Extensive experiments at this Station by Traum^ have thus far failed to show that the bacilli in these nodules develop into virulent organisms or induce lesions in the experimental animals such as tubercle bacilli do. RE-TESTS OF REACTORS NOT PERMITTED One reaction to the tuberculin test is considered evidence that an animal is tuberculous. Nothing can be accomplished by a re-test except possible confusion in the mind of the owner, as an animal that has once reacted may not react to a subsequent test ; but, at the same time, it may become a dangerous spreader of tuberculosis. Once a reactor, always tuberculous is the only safe motto in this respect. The state and federal authorities do not allow official re-tests on animals that are known to have positively reacted to tuberculin. DISPOSING OF REACTING CATTLE The California law^ requires that cattle which react positively to the tuberculin test be branded on the left jaw with the letter T. In lieu of branding pure-bred cattle, the registry name and number and photographs may be filed at the office of the State Department of Agriculture, Sacramento. Only an approved licensed or official veter- inarian may legally test cattle with tuberculin in California, and he must report the results of all tests to the State Department of Agri- culture, Sacramento. That office has supervision over the disposition of tuberculin to be used on animals in this state. The retention of reacting branded cattle in herds, the milk from ivhich is pasteurized, is a procedure sometimes resorted to instead of their slaughter for beef. Under special conditions it is also permis- sible to sell known tuberculous cattle to be placed in infected herds. The retention of reacting cattle in herds from which milk or milk products are being used in a raw or unpasteurized condition is illegal in California. Slaughter for beef under inspection is the recommended method for disposal of most reacting cattle which show no visible signs of the disease, except in those cases where the beef value would be very much less than the dairy or breeding value. The method formerly 7 Traum, J. Lymphangitis in cattle caused by acid-fast organism. Cornell Veterinarian 13:240-245. 1923 8 Statutes of California, 1927, chapter 47. 14 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [CiRC. 21 and most commonly employed of disposing of reacting animals was by slaughter and burial. Where this wasteful method has been employed the results have been discouraging; even when the state recompensed the owner in part for the loss of his stock, it has been unsatisfactory and is now seldom practised. A large proportion of reacting animals are usually only slightly diseased. They readily take on flesh and can be fattened and used for beef. The University prac- tices what it preaches in this regard, in that reacting cows are sold for food purposes under official municipal, state or federal inspection. In every case, cattle must- be carefully examined by an official inspector when killed and if the disease is found to be extensive, the carcass must be condemned. The federal government meat inspection regulations admit the use for food of meat from animals that show limited lesions of tuberculosis in the non-edible viscera, for it is recognized that the meat, itself, does not contain tubercle bacilli and, besides, the common procedure of cooking meat is a further safeguard against danger. The disposition of reacting cattle depends upon various conditions; these are more fully discussed later in this circular. FACTORS IN THE CONTROL OF BOVINE TUBERCULOSIS In the application of any methods for the eradication or preven- tion of tuberculosis certain important characteristics of the disease should be borne in mind : (1) Its indigenous nature. Bovine tuberculosis is so firmly rooted and so widespread among dairy cattle that it is exceptional for an important dairy community to be free from it. The possibility of eradicating bovine tuberculosis from individual herds and from certain entire counties has been demonstrated beyond all question, and the obstacles which have prevented the successful accomplish- ment of this in states, or countries have been due to the unwillingness of the people to make the necessary financial sacrifices. (2) Its specific nature. Tuberculosis does not develop sponta- neously. The cause of the disease is the bacillus of tuberculosis which exists only in the bodies of tuberculous animals and in their secretions, or in substances contaminated by them. In-and-in breeding cannot produce it. Dark, filthy, badly ventilated stables, poor food and crowded conditions may contribute to its rapid spread among cattle, but the disease does not originate in an animal, no matter how bad its environment. It must be exposed to the disease germs to contract the disease. 1928] BOVINE TUBERCULOSIS 15 (3) Its infectious nature. Tuberculosis is easily transmitted. This point, in connection with its specific nature, cannot be too strongly emphasized. The disease results from the association of tuberculous cattle with healthy ones and under such conditions will spread in spite of every sanitary precaution. It is a mistake to assume that the disease cannot thrive and multiply among dairy cattle kept under ideal conditions. The invigorating influence of fresh air and sunshine, wide, well watered pastures, well ventilated, ideally con- structed, immaculately clean barns, and abundant and well balanced rations will not stop, although they are likely to retard, the spread of the disease. It is among some of the best kept herds that the disease has been found to be alarmingly prevalent. Contact, direct or indirect, is the chief way in which the disease is disseminated. Calves most frequently contract the disease from the milk. Calves and hogs fed on unpasteurized milk from tuberculous cows soon become infected. SUPPRESSION OF THE DISEASE BY THE COW OWNERS The first step in getting rid of the disease is to find out how many of the herd are affected. A veterinarian should apply a tuberculin test and make a careful physical examination of each animal. The proper course to j^ursue then will depend largely upon the propor- tion of reactors found. The Suppression of Tuherculosis in Slightly Infected Herds. — Suppose a few cattle react, say, less than 15 per cent. Individual owners of such herds are advised to start to exterminate the disease immediately. The steps necessary are : 1. Dispose of all the reactors, including cattle which may have given doubtful or questionable reactions. Non-reactors which on physical examination show any symptoms attributable to tuberculosis must be included. 2. Thoroughly clean and disinfect the premises.^ Since chemical disinfectants in dilutions practicable for the liberal use required in disinfecting stables and corrals act very slowly in killing tubercle bacilli in exudate and secretions, most dependence should be placed on thorough cleaning, painting, and whitewashing. Particular atten- tion should be given to the absolute removal of all damp manure, the smallest particles of which may harbor innumerable tuberculosis 9 For a description of methods of stable disinfection, write to the Office of Information, United States Dei^artnient of Agriculture, Washington, D. C, for Farmers' Bulletin 954. 16 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [Cmc. 21 germs. In perfectly dry manure or soil, the tubercle bacillus dies in a few weeks, but under moist conditions it has been found to live for over a year. 3. Re-test the herd in sixty or ninety days by applying the intra- dermic or subcutaneous combined with the sensitized ophthalmic method, immediately remove all reactors and again clean and disin- fect. Every six months make a tuberculin test. Even when the herd is believed to be free from reactors, annual testing is recommended. 4. Additions to the herd should be subjected to the tuberculin test and should come from herds that are free from reactors. When purchasing cattle it is often impossible to find any for sale from herds known to be free from tuberculosis. Under such conditions, they should be obtained from herds in which the percentage of reactors is low. The purchase of cattle from badly infected herds, even when they pass the tuberculin test, is dangerous. There is great danger in buying non-reacting cattle from infected herds — that is, animals that have been exposed to infection. The unit to deal with in buying cattle is the sound herd rather than the non-reacting individual animal. In the dairies near cities, where it is not economical to raise the calves and the milking herd is kept up by the constant purchase of '^springers," or fresh cows, it will be impossible to keep the herd free from reactors, although in certain dairies of this class the number of reactors is kept down to an average of about 3 per cent by semi- annual testing and the prompt removal of reactors. The Suppression of Tuberculosis in Moderately Infected Herds. — In herds having from 15 to 35 per cent of reactors the best course to pursue is not as definitely known as in badly infected herds or in slightly infected ones. The system advocated some years ago of trying to retain under isolated conditions a group of reactors in order to secure healthy calves from them is practicable only when entirely separate barns, fields, and equipment are available; that means, in fact, the maintenance of two separate farms. In badly infected herds, one should proceed as if every animal were infected. In herds having over 35 per cent of reactors all of the mature cattle should be treated as if infected. The tuberculin test is of value in indicating that a severe infection exists, but not of value in such herds as a means of dividing the non-infected from the tuber- culous animals. To control the disease dependence must be placed upon the following procedure : 1. Eliminate promptly all animals developing physical signs of the disease. 1928] BOVINE TUBERCULOSIS 17 2. Eemove all calves at birth and raise them on boiled or pasteur- ized milk, or a solution of dry skim milk. 3. Keep all healthy young" stock isolated from the infected herd and infected fields and water. Test them every six months by the intradermic method and remove any reactors.^^ Calves are so seldom born tuberculous that intrauterine trans- mission is not an important factor in the control of the disease. Further, when calves do become infected, they react satisfactorily to the intradermic tuberculin test and seldom develop into spreaders until maturity; hence, it would require only one generation of cattle to eradicate tuberculosis. In carrying this principle into effect the ideal way would be to build up a separate herd from the healthy young stock. BCG VACCINE A. Calmette, of the Pasteur Institute, Paris, and C. Guerin, of the Pasteur Institute, Lille, France, observed a culture of bovine tubercle bacilli, grown on glycerine-bile-potato, which became reduced in viru- lence so that no injury resulted when 50 to 100 milligrams of such g-rowth were injected under the skin of the dewlap of calves. They claim that calves may be resistant to tuberculous infection in this way, and have named the vaccine BCG (bile-treated bacilli of Cal- mette and Guerin). Trials on calves are being made in several European countries, also in the experimental herd of the California Agricultural Experi- ment Station. No injury appears to have resulted from the injection of young calves or the annual re-injection of heifers. The atten- uated bacilli, however, remain alive in the tissues at the point of injection for a long time, and although no spread or reactivation has thus far been noted, it is not yet known what the effect will be on cows subjected to the strain of pregnancy and prolonged lactation. It will also require several years to determine the degree of resistance to tuberculosis conferred by BCG. Results at the California Station indicate that this vaccine can have only a very limited field of use- fulness in the eradication of tuberculosis in farm animals under conditions as they now exist in the United States. 10 Even when the non-reacting cattle are at once removed from a herd having over 35 per cent reactors, they should be looked upon as suspicious. 18 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [CiRC. 21 THE IMPORTANCE OF SEGREGATION AND ISOLATION In large herds it is advisable to keex3 the cattle in small units. In constructing buildings and corrals, plan at the least to have separate corrals for each group of fifty or sixty cattle. Provide separate watering-troughs for each corral. Train the cows to stand always in the same stanchion. Do not feed the calves with the sweep- ings from the feeding-troughs in the dairy barn and do not permit hogs or goats in the cattle corrals. MAKING CATTLE ENVIRONS FREE FROM INFECTIVE TUBERCULOUS MATERIAL In four series of experiments, Traum^^ found that tubercle bacilli contained in the discharges of tuberculous cattle when exposed on the ground in a layer of manure from one-half to one inch in thickness failed to produce tuberculosis in guinea pigs and cattle soon after the medium in which they were contained was sensibly dry. In one such series, this occurred seventeen days after manure containing tubercle bacilli was placed on the ground. In the case of tubercle bacilli con- tained in manure as above but kept continuously moist, as in a water- hole, they were found to be capable of producing tuberculosis in guinea pigs 687 days after exposure in one series and 548 days after exposure in another. To date, it has been found that such tuberculous material, when mixed with manure and kept moist for 255 days, produced tuberculosis in three out of five cattle when placed in their drinking water. Eighteen out of twenty-one cattle similarly exposed earlier in the experiment also developed tuberculosis. After 255 days, recognizable infected material was no longer found, and cattle exposures in this series were discontinued. SUGGESTIONS REGARDING SANITATION Construct water troughs so that the drinking water of the cattle does not become contaminated wdth manure. Do not allow the cattle access to ponds or water holes. Have plenty of windows to admit an abundance of sunlight to all buildings. Direct sunlight is more deadly to fully exposed tubercle bacilli than carbolic acid, cresol, corrosive sublimate or chloride of lime in the dilutions general used in disin- fecting. 11 Traum, J. Making cattle environs free from infection eliminated by tuber- culous cattle. Jour. Amer. Vet. Med. Assn., 52:289-299, 1918, and Eeport Calif. Agric. Exp. Station 1920-1921. p. 27. 1928] BOVINE TUBERCULOSIS 19 One would suppose that ti^ht barns would be unnecessary in Cali- fornia, where the cows can live out of doors for a greater length of time than in the eastern states, but it must be admitted that the cli- mate of the coast counties requires warm shelter for high-grade dairy cows. Ventilation is a sanitary factor which in some instances has been neglected. This should be provided not only in milking stables but also in the barns used exclusively for shelter and feeding. HOW CLEANLINESS HELPS The desirability of cleanliness in milking, cooling, and transporting milk is realized by all. Few, however, realize the significance of cleanliness as a factor influencing the health of the cattle. Since the manure of tuberculous cattle often contains living tubercle bacilli in vast numbers, the importance of keeping it well cleaned out of the stable and corrals is readily seen. Stables should be cleaned out regularly and the manure put where it cannot be picked over by hogs or cattle. These animals are easily infected in that way. Cleanliness also includes keeping the walls and ceilings free from dirt, dust and cobwebs. These are all good resting places for disease germs. Whitewashing the interior of the stable at least twice a year is a great aid to cleanliness and also has a distinct effect in destroying disease germs, especially when applied after thorough cleaning. In many municipalities dairy stables are required to be whitewashed at regular intervals. This should be a universal practice. HOW A HEALTHY HERD WAS BUILT UP FROM ONE BADLY DISEASED A California dairy herd, consisting of approximately 800 pure- bred and high-grade Holstein-Freisian cows, had been operated for many years under the handicap of extensive tuberculosis and abortion disease. Seven years ago it was decided to try to "breed out" these diseases. At that time 78 per cent of the herd reacted to the tuber- culin test and 28 per cent reacted to a blood test for abortion disease. By removing the calves to another farm and feeding them pasteurized milk, about 1300 healthy heifers have been raised. To April, 1928, 650 of these have reached maturity and have given birth to one or more calves, and, in addition, about 100 heifers and a large number of bulls have been sold. The young animals were tuberculin tested at least once every six months and the adult cattle at least once a year. One and one-half 20 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 21 per cent of the calves reacted at the first test and were removed. In May, 1927, about 10 per cent of the calves reacted to the test. This was traced directly to the carelessness of an unreliable employee in charge of pasteurization. Very few reactions have occurred at any subsequent test and no definite tuberculous lesions have been found in adult cattle. On April 11, 1928, the number being milked was 361, and there were only 33 head of dry stock. This ratio of milking to dry cows (11:1) indicates an exceptionally high degree of fertility. The procedure in feeding calves at this dairy has been quite suc- cessful, and, with the exception of the outbreak in 1927 mentioned above, no difficulty has been encountered in raising the calves on pasteurized milk heated to a temperature of 160° for twenty minutes. The cows calve in large pastures and the calves are removed between 24 and 48 hours after birth. This practice is more successful than having them calve in corrals. No colostrum is fed other than that which the calf may get before it is removed. Colostrum is never mixed with the milk to be pasteurized. For approximately six months, a special eifort was made to remove the calves as soon as possible after being dropped. No ill effects were observed even though most of the new-born did not receive colostrum. There then followed a period during which a large number of calves were unthrifty and a number died. A change was made and the calves were allowed to remain with their dams for from 24 to 48 hours. Coincident with this somewhat hazardous procedure, calves were more satisfactorily raised, and the practice has been continued to date. Up to the fifth or sixth week of age, the calves are fed pasteurized whole milk, at which time they are gradually changed to reconstituted skim milk, consisting of an 8 per cent solution of skim milk powder in warm water.^- The calves are also given constant access to ground oats to which a little salt is added. Bran and a small quantity of coconut or linseed meal are sometimes added to the oats. At the age of three or four months, the calves are given cottonseed cake in small amounts, and when they are first turned out to pasture, at from six to nine months of age (depending on the season of the year), cottonseed cake in the nut size is fed to them in troughs or scattered over the ground. 12 The use of powdered skim-milk is a great convenience in raising calves from tuberculous dams because it eliminates the work of pasteurization. At the University Experimental Dairy in Berkeley, it has been possible to put calves on a reconstituted liquid skim milk diet at five weeks of age, and at eight weeks to wean them to alfalfa hay, and a calf meal consisting of ground barley 4 parts, wheat bran 3 parts, dry skim milk 3 parts, salt 1 per cent. The proportion of dry skim milk was gradually reduced in the grain mixture as the calves aged. An immediately adjacent supply of water was found necessary to assist the calves in masticating the dry milk grain mixture. 1928] BOVINE TUBERCULOSIS 21 During the first five or six weeks the calves are kept in small, individual pens for the night and part of the day and, in fair weather, they are allowed to go into a pen where they get the full benefit of the sunshine. After this period they are moved into larger pens where groups of eight to ten are kept together. Following this and at further advanced ages, the groups are enlarged to fifteen and twenty- five, and, when first turned out on pasture, consist of from thirty to sixty. About 95 per cent of all the calves born normally during the first five years were raised to maturity. Calf disease lowered this percent- age to about 85 in the last two years. Conditions have now improved and, by the use of an auxiliary place and closing down operations for from thirty to forty-five days during the hot weather, this per- centage is climbing back to normal. Excellent housing facilities and constant attention to cleanliness have contributed to the attainment of such a low death rate. From both the financial and practical standpoints, such a plan, or a similar one, may not be feasible on many California dairies, especially upon the smaller ones. In such cases it is suggested that cooperative arrangements be inaugurated by a group of dairymen for developing clean herds from tuberculous ones. The calves may be removed to a community non-infected farm, be cared for as above outlined, and returned to the owner after he has disposed of his infected stock, or the adult cows may be removed to a community tuberculous herd and the offspring returned to the owner and reared by him. In any scheme the calves should be seperated from the dams shortly after birth, be placed upon non-infected environment and handled as outlined herein. Plans involving cooperation between OAvners would be more involved and the prospect of success less cer- tain than in separate herds under one management. ADVANTAGES TO THE OWNER OF A TUBERCULOSIS-FREE HERD 1. The reputation of the herd k enhanced. This is particularly valuable to owners of pure-bred stock and to those who raise grade milk stock for sale to market milk dairies. The practice of buying non-reactors from tuberculous herds has proved disappointing because, on re-test at the point of destination a proportion of such animals are frequently found to react. Buyers, after such an expe- rience, quickly learn to avoid the tuberculous herds. 2. Markets are gradually closing to the cattle and milk frow. tuberculous herds. The Territory of Hawaii will not receive cattle 22 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 21 except from accredited tuberculosis-free herds or from once-tested free herds. This is simply one example of the tendency to restrict the movement of cattle from herds not known to be free from the disease. This applies to both reacting: and non-reacting cattle from such herds. A few years ago before much progress was made in the control of bovine tuberculosis, the advantage of having a herd entirely free from this disease was not very evident, but the time now appears to be at hand when the owners of infected herds will either be forced to eradicate the disease or to operate under a distinct commercial disadvantage. Some municipalities now demand that even milk intended for the pasteurized milk trade must come from cattle which pass the tuberculin test and show no physical evidence of tuberculosis. It is probable that many more communities will soon insist upon similar requirements. 3. Tuhercidous herds show heavy losses. Sickness tends to increase in proportion to the development of tuberculous infection in a herd. In herds where only a small percentage of the cattle react, such losses may hardly be noticeable. In heavily infected herds, there is a loss, not only through the obviously direct wasting or fatal effect of the disease, but also from ailments not attributed by the owner to tuber- culosis, such as chronic mammitis, sterility, indigestion, diarrhea, chronic bloating and abscesses. THE ACCREDITED HERD PLAN Official recognition for herds that are free from tuberculosis may be arranged by owners of such herds by complying with certain state and federal rules. These rules define a tuberculosis-free accredited herd as one in which no animal affected with tuberculosis has been found upon two annual or three semi-annual tuberculin tests, and by physical examination, applied by a regularly employed veter- inarian of the United States Bureau of Animal Industry or of the state in which cooperative tuberculosis eradication work is conducted by the United States Department of Agriculture and the state; or one in which no animal affected with tuberculosis has been found upon two annual or three semi-annual tuberculin tests applied by an accredited and a federal or state veterinarian. Information concerning the methods and rules for the establish- ment and maintenance of tuberculosis-free accredited herds of cattle in California may be obtained by writing to the California State Department of Agriculture, Sacramento, or to the Inspector in Charge, United States Bureau of Animal Industry, Federal Building, Sacramento. 1928] BOVINE TUBERCULOSIS 23 THE CALIFORNIA TUBERCULOSIS FREE-AREA LAW By the terms of the California Statutes of 1927, Chapter 47, any county having not more than 10 per cent of its cattle infected with tuberculosis as shown by the records of the State Department of Agriculture, may obtain the cooperative assistance of the state and federal departments of agriculture in eradicating the malady. A survey to determine the percentage of reactors is not extended to any county unless requested through the county supervisors. When a county survey has been started by the California Department of Agriculture, the tuberculin testing of all cattle in the county becomes compulsory. According to officials of the California Department of Agriculture, when the enactment of the free-area law was under consideration, the subject of indemnity for the slaughter of reacting cattle was given careful thought. The conclusion was reached that, under prevailing conditions in California at that time, indemnity by the state would not be practicable. THE ADVANTAGES OF MODIFIED ACCREDITED AREAS Dairy and breeding cattle of good quality in areas free from bovine tuberculosis find a ready sale. Buyers seek those sections which have a reputation for healthy stock and the United States Bureau of Animal Industry has reported marked activity in inter- state shipments of high-class cattle from modified accredited areas in various parts of this country. Such areas have been defined by the United States Department of Agriculture as those in which a com- plete official tuberculin test of all cattle shows less than % of 1 per cent reactors, and which otherwise comply with regulations promul- gated by the department. Increase in the selling value of both cattle and hogs as compared with neighboring counties has followed the establishment of modified areas. In some sections the meat packing companies return a bonus of 10 per cent on all hogs from modified areas which do not show lesions of tuberculosis. The Live Stock Commissioner^^ of the National Live Stock Exchange, Chicago, reports that in Hillsdale County, Michigan, after accreditation, the farmers received an average of twenty-five dollars a head more than the selling price of cows of the 13 Smith, H, E. Tuberculosis as a livestock problem in tlie middle west. Jour. Amer. Vet. Med. Assn. 69:290-296. 1926. 24 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [CiRC. 21 same quality in the adjoining county. Cattle may be shipped from an accredited county to any point in the United States without the inconvenience or expense of a tuberculin test at the time of shipment. The accredited herd work is conducted cooperatively by the state and federal departments of agriculture. COUNTY LEGISLATION Progress in the control of bovine tuberculosis has been made in the southern part of this state through county ordinances. County tuberculosis eradication efforts, if operated independently of state and federal support, should not be expected to accomplish much unless they are well organized and liberally financed over a long period of time. Local tuberculosis ordinances should be carefully worded and limited to provisions which can be effectively enforced. STATE AND FEDERAL INDEMNITIES Provision is made in many states for the reimbursement of owners for losses in building up accredited tuberculosis-free herds. These usually are in the form of indemnities as follows: (1) The owner, in applying for accreditation, agrees to permit the slaughter of all reactors to the tuberculin test. (2) The dairy value of the reacting cattle is determined by a board of appraisers. (3) The reacting cattle are killed for beef at a slaughter-house having official meat inspection. If only slight lesions are found which do not involve an edible part, the carcass is passed as fit for food. If extensive lesions are present there may still be some salvage value in processing the carcass for fertilizer. (4) The loss represented by the difference between the appraised value and the salvage is usually shared equally by the owner, the state and the federal government. Some states assume two-thirds of the loss and the federal government the balance. For several years the United States Congress has appropriated annually several million dollars for such indemnities, but they are only available in states where provision is made for supplementary indemnities by the state. In California, indemnity provision cannot be made by the state because of limitations placed on the Legislature by the present state constitution; besides, indemnities have not been very urgently needed in California since it is not compulsory to 1928] BOVINE TUBERCULOSIS 25 slaughter tuberculin reacting animals in this state. There have, how- ever, been instances in the course of establishing tuberculosis-free areas where indemnities would have facilitated the work. Government indemnities not only save cattle owners from part of the loss forced upon them by official eradication measures, but also tend to pacify objectors and reduce opposition. In some states it has been observed that indemnities have a favorable effect on public sentiment in general that is helpful to bovine tuberculosis eradication programs. THE TOWNSHIP FREE-AREA METHOD In California no attempt has yet been made to carry out the tuberculosis-free area plan on units smaller than a county. Neverthe- less, it would seem appropriate to include in this circular a description of what is being done in New York State. According to E. T. Faulder^*, director of the New York State Bureau of Animal Industry, practically all tests in that state are made by the township area method. Testing is not inaugurated in any township until approximately 90 per cent of the cattle owners have first signed the accredited herd agreement, or 90 per cent of the cattle in the township are represented in the sign-up. Townships having the highest percentage signed are tested first and as many are tested during the year as the available indemnity funds will permit. In New York on March 1, 1928, all of the cattle had been tested in 449 townships, covering 47 per cent of the area of the state. Indemnity funds are available from state appropriations in New York for 90 per cent of the appraised value, not to exceed $90.00 for a grade animal or $150.00 for a registered pure-bred animal, such registration to have taken place before the date of appraisal. The salvage proceeds derived from the sale of the carcass are paid directly to the owner by the purchaser and are deducted from the appraised value, becoming a part of the amount of indemnity due, the owner receiving from the state the difference between the appraised value and the salvage value up to $90.00 for a grade animal and $150.00 for a registered pure-bred animal. The balance, if any, is paid by the federal government not to exceed $25.00 for a grade animal or $50.00 for a registered pure-bred animal. In no case can an owner receive as indemnities from all sources — salvage, state and federal — an amount exceeding the appraised value. 14 Faulder, E. T. Help eradicate tuberculosis. N. Y. State Dept. Agr. Cir. 350:1-26. 1926. 26 CALIFORNIA AGRICULTURAL EXTENSION SERVICE [ClRC. 21 WHY REACTING CATTLE MUST BE BRANDED WITH A "T" The prime object in branding reacting cattle on the jaw with the letter T, as required by California statutes, 1927, chapter 47, is to pre- vent tuberculosis animals from being moved, by purchase or other- wise, into tuberculosis-free herds. As long as recognized tuberculous herds exist and official permission can be obtained to remove the tuber- culin reacting cattle to such herds, the reacting animals should have a fair dairy value which is usually greater than that covered by indemnity in most states. One year's experience under the present California bovine tuber- culosis law has shown that the placing of a T brand on the jaw has caused an unjust depreciation in the sale value of the animal. In many instances beef buyers have taken advantage of the brand to reduce the price. Losses may be avoided to some extent by selling such animals on commission through a slaughter house having official meat inspection. Figures tabulated by the United States Bureau of Animal Indus- try show that the salvage received by certain original owners for tuberculous cattle killed in slaughter houses on a commission basis averaged more than 50 per cent higher than from similar cattle killed after having passed through the hands of one or more buyers. This tendency to take advantage of the presence of the T brand to beat down the price has been limited, we believe, to small dealers. THE ORDERLY MARKETING OF REACTING CATTLE The large firms in control of the meat packing industry in the central states have cooperated in many ways to promote tuberculosis eradication and in California similar cooperation could doubtless be expected both from packers and from existing organizations for orderly marketing. The Manager of the Western Cattle Marketing Association has assured the writers that that organization would be at the service of any officially recognized and properly constituted effort to market reacting dairy cattle for beef. The present relatively high value of dairy cattle for beef will more than offset in many instances the disadvantage in California of the lack of state and federal reimbursement funds since federal regula- tions limit appraisals to $75 a head for grade cattle and $125 a head for pure-bred animals. 1928] BOVINE TUBERCULOSIS 27 Since the eradication of tuberculosis is a problem of importance in financial as well as livestock circles, it would seem appropriate for all the business interests concerned to participate in a plan for the orderly marketing of reacting and branded cattle. In a statewide campaign of bovine tuberculosis eradication, the flow of reacting cattle to slaughter could be regulated to some extent by modifying the numbers tested in accordance with market condi- tions or arranging to hold and feed such animals with a view to getting as much as possible in beef value. THE NEED FOR TUBERCULOSIS-FREE CATTLE IN CALIFORNIA According to the report of the Los Angeles County Live Stock Department for the year ending June 30, 1927, approximately twenty thousand dairy cows were added to the herds of that county during the year. Thirteen thousand, or about 65 per cent, of the cattle were purchased in dairy districts outside the state of California. If cattle breeders in the central and northern parts of this state had been in position to meet the Los Angeles County requirements, over one million and a half dollars from that one county alone could have been spent within the state. There is a real need in California for expan- sion in the production of disease-free, high-grade heifers. STATION PUBLICATIONS AVAILABLE FOR FREE DISTRIBUTION BULLETINS No. No. 253. Irrigation and Soil Conditions in the 3 89. Sierra Nevada Foothills, California. 390, 262. Citrus Diseases of Florida and Cuba Compared with those of California. 391, 263. Size Grades for Ripe Olives. 268. Growing and Grafting Olive Seedlings, 392. 277. Sudan Grass. 393. 278. Grain Sorghums. 394. 279. Irrigation of Rice in California. 283. The Olive Insects of California. 304. A Study of the Effects of Freezes on 395. Citrus in California. 310. Plum Pollination. 396. 313. Pruning Young Deciduous Fruit Trees. 397. 324. Storage of Perishable Fruits at Freez- ing Temperatures. 398. 328. Prune Growing in California, 400. 331. Phylloxera-resistant Stocks. 402. 335. Cocoanut Meal as a Feed for Dairy 404. Cows and Other Livestock. 405. 340. Control of the Pocket Gopher in 406. California. 407. 343. Cheese Pests and Their Control. 344. Cold Storage as an Aid to the Mar- keting of Plums, a Progress Report. 4 08. 347. The Control of Red Spiders in Decid- 409. nous Orchards. 348. Pruning Young Olive Trees. 349. A Study of Sidedraft and Tractor Hitches. 410. 350. Agriculture in Cut-Over Redwood Lands. 353. Bovine Infectious Abortion, and As- 411. sociated Diseases of Cattle and New- born Calves. 412. 354. Results of Rice Experiments in 1922. 357. A Self-Mixing Dusting Machine for Applying Dry Insecticides and Fun- 414. gicides. 358. Black Measles, Water Berries, and 415. Related Vine Troubles. 416. 361. Preliminary Yield Tables for Second- Growth Redwood. 417. 362. Dust and the Tractor Engine. 363. The Pruning of Citrus Trees in Cali- 418. fornia. 364. Fungicidal Dusts for the Control of 419. Bunt. 366. Turkish Tobacco Culture, Curing, 420. and Marketing. 367. Methods of Harvesting and Irrigation 421. in Relation to Moldy Walnuts. 422. 368. Bacterial Decomposition of Olives During Pickling. 423. 369. Comparison of Woods for Butter Boxes. 424. 370. Factors Influencing the Development of Internal Browning of the Yellow 425. Newton Apple. 426. 3 71. The Relative Cost of Yarding Small and Large Timber. 427. 373. Pear Pollination. 374. A Survey of Orchard Practices in 428. the Citrus Industry of Southern California. 375. Results of Rice Experiments at Cor- 429. tena, 1923, and Progress in Experi- 430. ments in Water Grass Control at the 431. Biggs Rice Field Station, 1922-23. 377. The Cold Storage of Pears. 432. 380. Growth of Eucalyptus in California Plantations. 433. 382. Pumping for Draininge in the San Joaquin Valley, California. 434. 385. Pollination of the Sweet Cherry. 386. Pruning Bearing Deciduous Fruit 435. Trees. 3 87. Fig Smut. 388. The Principles and Practice of Sun- Drying Fruit. Berseem or Egyptian Clover. Harvesting and Packing Grapes in California. Machines for Coating Seed Wheat with Copper Carbonate Dust, Fruit Juice Concentrates. Crop Sequences at Davis, I. Cereal Hay Production in Cali- fornia. II. Feeding Trials with Cereal Hays. Bark Diseases of Citrus Trees in Cali- fornia. The Mat Bean, Phaseolus Aconitifo- lius. Manufacture of Roquefort Type Cheese from Goat's Milk. Orchard Heating in California. The Utilization of Surplus Plums. The Codling Moth in Walnuts. The Dehydration of Prunes. Citrus Culture in Central California. Stationary Spray Plants in California. Yield, Stand, and Volume Tables for White Fir in the California Pine Region. Alternaria Rot of Lemons. The Digestibility of Certain Fruit By- products as Determined for Rumi- nants. Part I. Dried Orange Pulp and Raisin Pulp. Factors Influencing the Quality of Fresh Asparagus after it is Har- vested. Paradichlorobenzene as a Soil Fumi- gant. A Study of the Relative Value of Cer- tain Root Crops and Salmon Oil as Sources of Vitamin A for Poultry. Planting and Thinning Distances for Deciduous Fruit Trees. The Tractor on California Farms. Culture of the Oriental Persimmon in California. Poultry Feeding: Principles and Prac- tice. A Study of Various Rations for Fin- ishing Range Calves as Baby Beeves. Economic Aspects of the Cantaloupe Industry. Rice and Rice By-Products as Feeds for Fattening Swine. Beef Cattle Feeding Trials, 1921-24. Cost of Producing Almonds in Cali- fornia : a Progress Report. Apricots (Series on California Crops and Prices). The Relation of Rate of Maturity to Egg Production. Apple Growing in California. Apple Pollination Studies in fornia. The Value of Orange Pulp for Milk Production, The Relation of Maturity of fornia Plums to Shipping Dessert Quality. Economic Status of the Grape Industry. Range Grasses of California. Raisin By-Products and Bean Screen- ings as Feeds for Fattening Lambs. Some Economic Problems Involved in the Pooling of Fruit. Power Requirements of Electrically Driven Manufacturing Equipment. Investigations on the Use of Fruits in Ice Cream and Ices. The Problem of Securing Closer Relationship Between Agricultural Development and Irrigation Con- struction. Cali- Cali- and BULLETINS — (Oontinued) No. 436. 437. 438. 439. 440. 441. 442. 443. 444. No. 87. 117. 127. 129. 136. 144. 157. 164. 166. 178. 202. 203. 209. 212. 215. 230. 231. 232. 234. 238. 239. 240. 241. 243. 244. 245. 248. 249. 250. 252. 253. 255. 257. 258. 259. 261. I. The Kadota Fig. II. Kadota Fig Products. Economic Aspects of the Dairy In- dustry. Grafting Affinities with Special Refer- ence to Plums. The Digestibility of Certain Fruit By- products as Determined for Rumi- nants. Part II. Dried Pineapple Pulp, Dried Lemon Pulp, and Dried Olive Pulp. The Feeding Value of Raisins and Dairy By-Products for Growing and Fattening Swine. The Electric Brooder. Laboratory Tests of Orchard Heaters. Standardization and Improvement of California Butter. Series on California Crops and Prices: Beans. No. 445. Economic Aspects of the Apple In- dustry. 446. The Asparagus Industry in California. 447. The Method of Determining the Clean Weights of Individual Fleeces of Wool. 448. Farmers' Purchase Agreement for Deep Well Pumps. 449. Economic Aspects of the Watermelon Industry. 450. Irrigation Investigations with Field Crops at Davis, and at Delhi, Cali- fornia. 451. Studies Preliminary to the Establish- ment of a Series of Fertilizer Trials in a Bearing Citrus Grove. 452. Economic Aspects of the Pear In- dustry. CIRCULARS No. Alfalfa. 265. The selection and Cost of a Small 266. Pumping Plant. House Fumigation. 267. The control of Citrus Insects. Melilotus Indica as a Green-Manure 269. Crop for California. 270. Oidium or Powdery Mildew of the 273. Vine. 276. Control of Pear Scab. 277. Small Fruit Culture in California. The County Farm Bureau. 278. The Packing of Apples in California. County Organization for Rural Fire 279. Control. Peat as a Manure Substitute. 281. The Function of the Farm Bureau. Salvaging Rain-Damaged Prunes. Feeding Dairy Cows in California. 282. Testing Milk, Cream, and Skim Milk for Butterfat. 284. The Home Vineyard. 286. Harvesting and Handling California 287. Cherries for Eastern Shipment. 288. Winter Injury to Young Walnut 289. Trees During 1921-1922. 290. The Apricot in California. 292. Harvesting and Handling Apricots 293. and Plums for Eastern Shipment. 294. Harvesting and Handling California 296. Pears for Eastern Shipment. Harvesting and Handling California 298. Peaches for Eastern Shipment. Marmalade Juice and Jelly Juice 300. from Citrus Fruits. 301. Central Wire Bracing for Fruit Trees. 302. Vine Pruning Systems. 304. Some Common Errors in Vine Prun- 305. ing and Their Remedies. 307. Replacing Missing Vines. 308. Measurement of Irrigation Water on 309. the Farm. 310. Support for Vines. Vineyard Plans. 311. Leguminous Plants as Organic Fer- 312. tilizers in California Agriculture. The Small-Seeded Horse Bean (Vicia faba var. minor). Thinning Deciduous Fruits. Pear By-Products. Sewing Grain Sacks. Plant Disease and Pest Control. Analyzing the Citrus Orchard hy Means of Simple Tree Records. The Tendency of Tractors to Rise in Front; Causes and Remedies. An Orchard Brush Burner. A Farm Septic Tank. Saving the Gophered Citrus Tree. Home Canning. Head, Cane and Cordon Pruning of Vines. Olive Pickling in Mediterranean Countries. The Preparation and Refining of Olive Oil in Southern Europe. The Results of a Survey to Deter- mine the Cost of Producing Beef in California. Prevention of Insect Attack on Stored Grain. The Almond in California. Milk Houses for California Dairies. Potato Production in California. Phylloxera Resistant Vineyards. Oak Fungus in Orchard Trees. The Tangier Pea. Alkali Soils. The Basis of Grape Standardization. Propagation of Deciduous Fruits. Control of the California Ground Squirrel. Possibilities and Limitations of Coop- erative Marketing. Coccidiosis of Chickens. Buckeye Poisoning of the Honey Bee. The Sugar Beet in California. Drainage on the Farm. Liming the Soil. American Foulbrood and Its Control. Cantaloupe Production in California. Fruit Tree and Orchard Judging. The Operation of the Bacteriological Laboratory for Dairy Plants. The Improvement of Quality in Figs. Principles Governing the Choice, Op- eration and Care of Small Irrigation Pumping Plants. The publications listed above may be had by addressing College of Agriculturey University of California, 8m-9.'28 Berkeley, California.