were killed and examined. Most of them were free from stomach worms, but in some the parasites were present in small numbers.

In earlier experiments the suckling-pen method gave more favorable results, and the writer was led to believe that it might be of some practical use. Since it can not be depended upon absolutely to prevent infection in lambs, as shown by the latest experiment, it is probably not of much practical value. It is not, however, a very troublesome method, as the ewes and lambs soon learn their way back to their proper pastures, and are easily separated after each suckling period. A noninfected pasture is required for the lambs, and since this pasture would become more or less infected as a result of the failure to prevent absolutely the infection of the lambs, it becomes necessary to employ a different pasture for the next crop of lambs, using the same pasture only in alternate years and excluding all ruminants from it in the interim in order to allow any infection which may be present to die out. However, fields adjacent to the ewe pasture might be utilized temporarily as pastures for the lambs and the necessity of maintaining two permanent lamb pastures thus avoided.

The failure of this method to prevent infection entirely is probably due to a circumstance already mentioned, namely, the more or less common occurrence of larval stomach worms upon the skin and wool of the ewes, whence they may sometimes be taken into the mouth. of the lambs while suckling and be swallowed.

Inasmuch as there is no known method of handling lambs from infested mothers so as to avoid absolutely stomach-worm infection, with the exception of that in which the lambs are raised by hand, we must be content with reducing the amount of infection as much as possible and keeping the sheep and lambs in as good physical condition as practicable, so that they may be better able to tolerate the parasites from which they can not escape. In some cases it may be possible to employ the suckling-pen method to advantage in spite of its apparent impracticability. As to schemes for avoiding infection by the rotation of pastures, it is evident that a rotation plan, in which an attempt is made to keep pace with the development of the embryonic stomach worms by moving the sheep from one pasture to another before embryos hatching from eggs passed in the feces of infested members of the flock have developed to the infectious stage, is out of the question.

COMBINED PASTURE ROTATION AND MEDICINAL TREATMENT.

Recognizing the impracticability of moving sheep from one pasture to another frequently enough to avoid entirely the infection. which develops in the pastures, we may next consider a plan for reducing infection by a combination of occasional rotation and

medicinal treatment. In following this plan some losses may occur during the first year or two unless noninfected pastures or fields are available to start with, but thereafter there should be no losses whatever.

This plan may be inaugurated at any time of the year. Supposing that it is to be begun just after lambing, say in March, it is advised that all of the sheep except the lambs be given a preliminary treatment with bluestone, coal-tar creosote, or gasoline, in accordance with the directions given in Circular 102 of the Bureau of Animal Industry. Any cattle or goats that may be on the farm must either be treated in the same manner as the sheep, being dosed for worms and moved from pasture to pasture in company with the sheep, or else be kept strictly apart from the latter in pastures of their own.

After the preliminary treatment, which will destroy a large proportion of the stomach worms that may be present, the sheep, lambs, and all other ruminants are removed to a pasture or field which may be termed pasture No. 1. Preferably this should be a pasture which is free from infection, but if such a pasture is not available, use an infected pasture, and some time in the summer, say the 1st of July, give the entire flock, lambs and all, another course of treatment and move them to a second pasture. The 1st of November another treatment for stomach worms is given, and the animals are moved to pasture No. 3, where they remain until the 1st of March. After this first year's treatment the medicine is given only in the fall, just before the sheep and cattle are moved to the pasture in which they spend the winter. On the 1st of March of the second year they are moved to pasture No. 4, then on the 1st of July to pasture No. 1, from which since July 1 of the preceding year all ruminants have been excluded, but which meanwhile may have been used if desired for live stock not subject to stomach worms, such as horses, mules, or hogs. November 1 the sheep and cattle, after being dosed for worms, are moved to pasture No. 2, from which, as in the case of pasture No. 1, all ruminants have been excluded since the corresponding date of the year before. Then in March pasture No. 3 is occupied again, and so on, from pasture to pasture in regular rotation.

By utilizing the pastures for other live stock during the periods that ruminants are excluded, the land included in the rotation scheme may be made use of more or less continuously. In lieu of some of the pastures, fields might be planted with suitable crops, and made to serve temporarily as pastures, and employed for other agricultural purposes, if desired, when not in use as pastures.

It is very probable, particularly in the case of badly infested flocks and farms, that the foregoing plan will at first fail to prevent entirely the loss of lambs from stomach worms. The flock should be watched closely, and if any of the lambs present symptoms of stomach

worms they should receive proper medicinal treatment. The pastures must not be heavily stocked, especially at first. The more numerous the sheep relative to the size of the pasture, the more heavily infested will the pasture become, and with close grazing the sheep are not only liable to pick up greater numbers of larval stomach worms, but also, unless auxiliary feeding is practiced, may not receive a sufficient quantity of food, and thus be less able to endure parasitic infection. As salt acts to a certain extent as a preventive against stomach worms, as well as being a necessary element in the diet of ruminants, it should be supplied to the sheep in liberal quantities. If possible the use of wet, low-lying pastures should be avoided, or this condition corrected by proper drainage.

The plan which has been outlined above may be variously modified. For example, in a climate with a cold winter season the same pasture could, if desired, be utilized every year as a winter pasture. The sheep would not be placed in this pasture until winter had set in, and would be removed again just before spring began. As already noted, any stomach-worm eggs passed in the feces of the sheep during the winter would either be killed immediately by exposure to freezing weather, or on account of the prevailing low temperature lie dormant or develop slowly with the practical certainty of being killed by freezing on some later occasion before they had reached the infectious stage. The order of rotation in this case would be as follows: Pasture No. 1 until July, pasture No. 2 until winter begins, then to pasture No. 3 (the winter pasture), then at the end of winter to pasture No. 4, then in July to pasture No. 1, then to the winter pasture (No. 3), then to pasture No. 2, etc.

FEEDING TOBACCO.

There has been considerable discussion recently in various livestock and agricultural journals concerning the feeding of tobacco to sheep as a remedial measure against stomach worms. I will, therefore, in conclusion, briefly refer to some experimental work along this line conducted at the Experiment Station of this Bureau.

In June, 1908, a flock of sheep and lambs, in which stomach worms. were known to be present, were separated into three lots with 5 lambs and 7 or 8 full-grown sheep in each, and placed in three similar small pastures. Lot 1 was fed leaf tobacco grown in Maryland, lot 2 tobacco cuttings obtained from a cigar factory, while lot 3 was fed no tobacco at all. Some difficulty was experienced in getting the sheep in lot 2 to eat the cuttings, and they finally had to be started on the leaf, afterwards changing to the cuttings, so that it was not until late in July that they really began to consume the cuttings. By the middle of August the sheep in each of lots 1 and 2 were consuming

10 ounces of tobacco every two days, an average per head of a little over two-thirds of an ounce every forty-eight hours. This represented the maximum which they would eat, and the feeding of this quantity every forty-eight hours was continued until early in December. There was no noticeable difference in the condition of the sheep in the three lots, which remained fairly good throughout the experiment. One lamb in the lot which was not fed tobacco died in July from unknown causes, no post-mortem examination being possible as the carcass was devoured by buzzards before the death of the animal was discovered. In the latter part of December and the early part of January the lambs and some of the ewes were killed and examined, with the result that stomach worms were found to be present in all three lots. In most cases there were only a few, but in one lamb several thousand stomach worms were found. Strangely enough this was a lamb from one of the lots which had been fed tobacco.

The conclusion reached in this experiment is that the feeding of tobacco had no noticeable effect either upon the stomach worms or upon the sheep. The results obtained can not be considered decisive, but they suggest the possibility that the favorable reports which have been made relative to tobacco as a remedy for stomach worms have been based on coincidences, the good results observed in such instances having been due to some other cause than the tobacco. In fact it has been noted that some sheep raisers who have tried tobacco have reported it a failure. At the present time, therefore. tobacco must be considered a remedy of doubtful efficiency so far as stomach worms are concerned.

By JOHN R. MOHLER, A. M., V. M. D., Chief of the Pathological Division,

AND

GEORGE H. HART, V. M. D., M. D., Assistant in Bacteriology, Pathological Division.

PRELIMINARY REMARKS.

A gradually increasing interest has been manifested during the past few years in the milch-goat industry, and numerous requests for information on this subject are constantly being received by the Bureau of Animal Industry. These requests have come chiefly from physicians who believe in the value of goat's milk for invalids and children, and from people who have either read of the economy of goat keeping or been raised in foreign countries where the milk of goats is such a valuable asset. For instance, milch goats are particularly adapted to the requirements of the peasant class in Italy, Spain, Switzerland, Germany, Austria, and other countries, and it is because the milk of the goat is furnished cheaply and compares favorably with the quality of cow's milk that the milch goat recommends itself to those people in this country who can not afford to keep a cow.

The common American or Spanish goat has been kept for milk production in the United States for a long time, especially in certain States with Italian colonies and in several of the Southern and Southwestern States, but the number of such milch goats is known to be comparatively small. In fact, it was this scarcity of milch goats, and the desire of the Bureau to secure a herd of clean, healthy, hardy milch animals especially for the purpose of serving as foundation stock to supply those interested in the building up of a milch-goat industry in this country, that caused Dr. D. E. Salmon, then Chief of the Bureau of Animal Industry, to make an importation of milch goats from Europe, where this industry is an important and profitable interest. The late Mr. George F. Thompson, who had spent considerable time in studying the different species of these animals, was detailed to make this importation. After visiting several districts in Europe, he finally turned his attention to the Maltese goat and soon became convinced that this was a valuable breed and should be introduced into the United States. These goats are native to the Island of Malta in the Mediterranean Sea, and are also bred to a less extent on the rock of Gibraltar, having been introduced there from Malta.