Symud i'r prif gynnwys
Cuddio Rhestr Erthyglau

12 erthygl ar y dudalen hon



■ i A GUI CULTURE. I FOOT EOT IN SHEEP. 1 The following hints upon this disease and its remedy is taken from the Field:—Foot rot attacks or all of the feet of the sheep, bat most commonly affects ona of thesa organs a severely than the others, and on this account is sometimes considered to be confined to one, when, if a careful examination were made, it would be found to exist in some degree in all of them. The disease shows itself by a loosening 0 of the horn, and the development of a peculiar spongy structure upon the membrane of the internal foot. When the malady is fully developed the spongy appearance extends over the greater portion cf the foot mast affected, and the hoof horn can be readily detached from the secreting membrans; but during I the examination of several cases many degrees of the malady will be observed, and it ia extremely interest- ing to trace the disease from the commencement to its termination. Upon a cursory examination of a flock among which foot rot has broken out, some of the sheep will be be excessively lame, others only slightly affected, and some not at all. To got an idea of the various stages through which the disease passes before it becomes obvious enough to excite attention, the first inspection should be made upon some of the aaimal3 that appear to be perfectly free from the affection, but in many of whose feet it has neverthe- less begun. A very careful examination, after the hoof has been well cleaned, will lead to the detection of some trifling alterations of structure that are of much greater importance than they appear to be. In one case a small black line, not more than the eighth of an inch long, may be observed on the side of the hoof horn, midway between the coronet and the ground surface. If a section were made through this small point, it would be found to be the begin- ning of a canal which is filled with dirt, and takes a direct course downwards and inwards to the interior of the foot. Another foot may present a dark spot extending from the ground surface a third of the way towards the coronet. This sign can only be distinguished in a light-coloured foot, and is always the result of a cavity formed by the entrance of dirt or gritty particles at some small fisanre at the juncture of the wall and sole of the hoof. The gritty matters will generally be found to have advanced a considerable distance towards the interior of the foot, but until they actually enter it no pain nor lameness appears to be occasioned. Farther investigation will enable the examiner to detect some cases of shrivelling of the toe of the hoof and the accumulation of grit in many little honeycomb spaces; or he may observe, in certain instances, that the out- side wall of the hoof at tha ground surface is turned under, affording a lodgment for dirt, which is pressed upwards every time the animal throws his weight upon the part. Passing on to those sheep which give evidence of slight lameness, it will be found that two or three, perhaps, ofthe hoofs present the appearances described, while one foot is affected with the disease in a more advanced form. In this foot the horn is broken or ragged, some heat and swelling are noticed round the coronet, and, upon removing some of the looser horn, the peculiar spongy structure is seen beneath, and probably a little matter may be seen. Extending the inspection to the worst cases, more marked symptoms will be perceived. In many instances the hoof will be elongated to an extraordinary degree; and, if the knife be employed, it will be found to be detached throughout its whole extent, and the membrane to be covered with the spongy granulations. Sometimes the horn, instead of being elongated, is much broken, and the spongy masses protrude through fissures in the sole and wall; but whatever may be the aspect of the horn, the internal membrane always presents the curious fungoid appearance, and the connection be- tween it and the external covering of horn is always destroyed in these extreme cases of the disease. The circumstances under which foot rot occurs are pretty well known. Certain lands are celebrated for causing it while it happens upon others under special conditions only. Two requisites appear to be neces- sary for the production of the disease-moisture, either from the excessive fall oi rain or from the ab- sence of drainage; and, next, the presence of gritty Tjarticles. Thus foot rot is almost certain to affect sheep in wet, undrained, clay soils, containing an ad- mixture of sand; whether such land be high or low is of no material consequence. It also occurs on chalky soils in wet seasons, and, under similar circum- stances, upon loose, porous, sandy soils. The sand and grit appear to be the active agents in the produc- tion of the derangement; the moisture plays the pre- liminary part of softening the horn, and affording fa- cilities for the entrance of the foreign particles; these rapidly proceed to the interior of the foot, excite in. flammation, which is attended with the development of the fungoid growth, and a quantity of serous fluid, which keeps it in a soft spongy state, and ultimately the entire hoof is separated from its secreting sur- face. It is possible that caaea of foot rot may now and then happen in dry soils where there is an abund- anoe of grit, particularly if the hoof should become cracked by accident sufficiently to allow of the ingress of small particles of sand; but, taking foot rot as it generally happens among a flock of sheep, it will be found to be the result of the influence of moisture and gritty particles acting in combination upon the horny tissue.



[No title]




[No title]


[No title]