SHEEP DIPPING

Hawke's Bay Herald-Tribune, Issue 68, 7 April 1937, Page 15

SHEEP DIPPING

Use Care and Avoid Losses CAUSES OF MORTALITY The provisions of the Stock Act require all long-wool or crossbred sheep to be .dipped in the North Island between the first day of January and the last day of March, and in the South Island between the first day of January and the last day of April. This enactment is provided as a means of exercising control in the infestation of sheep with external parasites, which tend to make sheep generally unthrifty, cause loss of blood from the animal, and damag8 the wool. Mr C. V. Dayus, of the Department of Agriculture, Dunedin, contributes an article on the subject to the March issue of the Journal of Agriculture. j It ie unfortunate, he says that a number of sheep are lost annually through carelessness in dipping, whieh is brought about in various ways. The maiority of deaths occur through aspiration of the dipping-fluid into the lungs, thus eetti.ng up an aeute broncho-pneu-monia, or through a highly toxaemie condition due to infection with the organisms which produce blood-poisoningj. Other causes Of mortality are chemical poisoning due to sheep actually swallowing the dipping-fluid, poisoning due to grazing contaminated pastures On which sheep have been turned without standing su£S.cient time to drain properly after .dipping, death from exposure to adverse climatic conditions. If any extensive mortality from one or more of these causes is experienced, it is highly probable that' there has been carelessness in the process of dipping, or in the management of the flock befoi^ and after dipping. Note of Warning It'is the purpose of this short not. not to elaborate the reasons and meui: of prevention of all these causes o mortality, but to sound a note o warning in regard to one partieula cause — viz., deaths due to infection wiri blood-poisoning organisms. During the last few. years it ha? been poseible to enquire into severa' cases where a rather high mortalil'-, . occurred in sheep after dipping fron; blood-poisoning due to the organisin producing malignant oedema (Vibrion septique). In at least some of these cases infection took place from the .dip* ping-bath itself, and it has been possible to recover ihe organism from the dipping-fluid, which was pathogenic for guinea-pigs. In fact, one sample of dip taken in April of last year still contains viable organisms pathogenic for guinuea-pigs. The common arsenicai preparations made up into". sheep-.dipping fluids have little or no bacteriological sction. and consequently, it is easy to imagine how a dip which has become polluted by the passage of large numbers of sheep becomes a source of infection wi.th an organism of which the soil is a natural habitat. There comes a time when sheep put through this highly infected dip contract infection through ekin abrasions due to xecent crutching, dog-bites, rough metal in holding- yards, jagged timber and projecting nails in pens or races, and feed "scald." All these causes of abrasions, in my personal knowledge have at some time or other been the means of infection being intro.duced. Gleaning the Dip It is important then to clean out the dip thoroughly at the commencement of ihe season aud again if necessary more than once during the season according to the capaeity of the dip and the number of sheep put through. This process should include the complete emptying of the dip, the removal of all .debris, and the disinfection of the empty bath, yards, etc., with some suitable and economical- antiseptic solution such as kerol or Jeyes fluid. In malignant oedema infection there is usually an area of skin highly discoloure.d often in the region of the brisket or running up inside the thigh, which is doughy to the touch, putting on pressure, due to the tissues at the pomt of invasion becoming infiltrated with yellow or red serum. The muscle tissue becomes an intense deep red, and is softened. Breathing is rapid, and the temperature is raised, and the sheep soon becomes moribund. Deaths usually take place 36 hours to 48 hours after dipping, and may continue until approximately the end of the fourth day after dipping. All animals dying from this cause should either be burnt or buried deeply, without skinning or opening, and tlie area ldressed with burnt lime. The disposal of the carceses is very important, as the organism sporulates in the soil, which increases the coneentration of infection if carcases are opened up and disposed of indiscriminately.