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The Rural Voice, 1991-11, Page 16FARMGATES FEEDERS FEED WAGONS RUGGED DEPENDABLE RELIABLE 3 models • 1" square tubing • 1 1/4" square tubing • 1 1/2" round pipe rs___ IIIIIIE1111 .v 14 7' X 8' Single Bale Feeder for 4' and 5 ' round bales and larger sizes available 'j' llf t('t' Econo Model Feed Wagon Good for round bales or forage Quick hitch tongue Pivoting front axle 12 gauge steel bottom Priced very reasonable $1600 F.O.B. Hawkesville For further information call: Owen Martin Manufacturing HAWKES V ILLE, Ontario 519-699-4144 12 THE RURAL VOICE DIAGNOSTICS MYCOPLASMA VACCINES - ANOTHER TOOL by DR. G.K.A. JOSEPHSON VETERINARY LABORATORY SERVICES Mycoplasma pneumonia is the world's most common swine disease, which costs Canadian pork producers an estimated $15 million a year. Enzootic pneumonia (the term applied to a pneumonia caused by Mycoplasma hyopneumoniae organisms and complica- ted by secondary bacterial infections) is reported to be present in the lungs of 79 per cent of pigs in 99 per cent of herds in the U.S. at time of slaughter. However, studies on the economic effects of these pneumonias have been inconsistent. Aver- age daily gains are said to have been re- duced by up to 25 per cent, depending on the study mentioned, with corresponding decreases in feed efficiency of between four and 25 per cent. The organism is spread via aerosol transmission from the young infected sow to her litter. Older sows tend to be non- infected and immune, and their litters are susceptible when their passive immunity wanes and they come into contact with infected pigs. When a pig becomes infected with My- coplasma hyopneumoniae, the organism damages the lining of the air passages, allowing other bacteria, which normally do not cause a problem, to gain entrance into the lung and cause severe damage. Herd outbreaks of pneumonia usually follow pe- riods of stress such as weaning, tempera- ture changes, overcrowding, and poor ven- tilation. Earliest signs can show up in pig- lets between three and 10 weeks of age, but most won't show clinical signs until three to six months of age (the grower/ finisher stage). Signs include a dry persis- tent cough that can last for several weeks, a reduced growth rate, decreased feed effi- ciency, and depression. Rapid, laboured breathing may be seen when the pigs are aroused. The severity increases when secondary bacteria are present. Although most of the pigs in a barn become infected, the death rate is usually quite low. Typically, the affected areas of the lung are the front and lower portions. Since the infection occurs early in life, lung lesions are often not present at slaughter, since the lesions regress with time. However, those pigs that have reco- vered, while immune to further disease, still shed the organisms. Since the severity of Mycoplasma - caused pneumonias is closely related to management and environmental condi- tions, attempts at controlling and prevent- ing disease losses have traditionally been aimed at these areas (closed herd; low pig density; all -in, all-out; etc.). These pro- grams are usually not totally effective. Preventative programs have also included prolonged antibiotic usage, but their cost- effectiveness may be negative except for herds with severe problems or very high sow replacement rates. In 1990, two vaccines were introduced to the Canadian market with claims that they reduced both the days to market and the severity of lung lesions in pigs affected with enzootic pneumonia. Vaccination, however, does not mean the pigs will not be infected. The lesions will be reduced in size, with fewer organisms shed by infect- ed animals. More important, though, is the improvement in growth rates that appears to follow the institution of a vaccination program. Initial reports on the use of these vac- cines has been promising in herds where there has been a severe pneumonia prob- lem that has been proven to be related to Mycoplasma hyopneumoniae. Depending on the type of operation (farrow -to -finish; finishing; breeding stock supplier; etc.) and the disease picture on the farm, vacci- nation of the entire herd or select groups of pigs has been practised. Following vac- cination, the number of clinical cases of pneumonia has dropped, resulting in reduced antibiotic usage — an obvious saving in itself. Days to market have also been reduced, although it is too early to determine if there has been an improve- ment in feed efficiency. Another area where the vaccine appears to be of benefit is in the vaccination of high -health status breeding stock, prior to their being introduced into conventional herds. The vaccines appear to be another tool in the fight against enzootic pneumonia, which, when used in conjunction with changes in management and environment, have the ability to improve the health status of our swine herds. Their usage at this time seems to be most beneficial when enzootic pneumonia is causing a severe problem on the farm.0 We have tried to keep our topics timely and informative. However, we would wel- come any suggestions from readers for future topics. We would also invite inter- ested persons to tour the facilities at the Diagnostic Laboratory at Huron Park. We would ask that you make prior arrange- ments by phoning 226-6691, Ext. 276.