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Parenteral vaccination of sows against Escherichia coli diarrhea in their newborn piglets has become more common during the last decade in Sweden, and the vaccination has generally had positive effects. For more than 20 years we have investigated E. coli strains isolated from piglets and wegned pigs with enteric disorders, noting the presence of 0 groups, enterotoxins, and adhesins. There has been a continuous change in`the frequency of these virulence factors. The present study was performed during 1983 and 1984 to follow this change, since such information is essential for the proper choice of vaccines. A total of 856 E. coli strains were obtained from 683 herds divided into three age groups: 1 to 6 days old, 1 to 6 weeks old, and weaned pigs. 0 group 149 still dominated in the last two age groups, while 0 group 101 was, for the first time, the most frequent 0 group in neonatal piglets. AU but four 0149 strains carried the K88 antigen, which was found in only one other strain (0 group 8). K99 antigen was most often found in 0 groups 101 and 64, and among all the K99 strains ST mouse was the most common (44 of 57), followed by ST mouse-ST pig strains (12 of 57). The 987P antigen was demonstrated in 26 strains belonging to 0 groups 141 and OX46 and nontypable strains. Two strains belonging to 0 group 101 were positive for F41 antigen; one of them also carried the K99 antigen. Among ail non-0149 strains, ST mouse was the most common type of enterotoxigenic E. coli (n = 88), followed in decreasing order by ST mouse-ST pig strains (n = 69) and ST pig strains (n = 33). In 114 strains producing enterotoxins no adhesive factor was found. Thus, vaccination of the Swedish sow population for more than 5 years with vaccines containing 0149 and K88 antigens has apparently changed the pattern of enterotoxigenic E. coli in neonatal diarrhea. The frequency of 0149:K88 strains has been reduced, and 0101:K99:ST mouse strains now dominate. However, 0149 strains remain the dominant 0 group in piglets older than 1 'week. In spite of all our diagnostic efforts, no virulence factors were detected in about one third of the piglets and weaned pigs with enteric disorders.

Summary Five hundred four‐year‐old Standardbred Trotters in training were examined in a study on the correlation between conformation, soundness and racing performance. In 39 horses marked hindquarter asymmetries were observed when they were standing squarely on all four feet. The asymmetries were seen as obvious height differences between the left and right tubera sacrale. In 30 cases the left tuber sacrale was lower and in nine cases the right tuber sacrale was lower. The horses showing hindquarter asymmetry were of significantly larger body size than the 461 horses not showing the asymmetry. There was no sex difference in the incidence of hindquarter asymmetry. The asymmetric horses had significantly lower total earnings, a lower number of races per horse and less good racing records (min/km) than the remaining 461 horses. The trainers reported that the asymmetric horses often had difficulties in performing at speed. In most horses, the asymmetry had not been observed until the examination. Past clinical records of 11 of the 30 asymmetric horses were available. In only one of the 11 horses had the asymmetry been considered of clinical importance. It was concluded that the described hindquarter asymmetries are important signs indicating that there is an enhanced risk that the affected horses will not become successful Trotters.

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The present investigation comprised six integrated herds (100-150 sows each) and one specialized fattening herd. Serologic tests by ELISA were performed on blood samples from piglets and growing pigs during various rearing phases in order to determine the presence of Actinobacillus infection and to estimate the age of the animals at onset of the disease. Using this information, herdspecific vaccination programs were designed against Actinobadlus pleuropneumoniae serotype 2. The weaned piglets in the integrated herds were vaccinated twice before being moved to the fattening unit. In the specialized fattening herd, the pigs were vaccinated on arrival at the growing unit and just before transfer to the finishing unit. The frequencies of chronic pleuritis at slaughter demonstrated that a vaccination program adapted to the herd-specific problem, in combination with environmental improvements, reduces the prevalence of chronic pleuritis. O n the other hand, only a moderate reduction of the prevalence of chronic pleuritis occurred as a result of vaccination if no environmental improvements were made. In two of the herds during the vaccination period, the number of feeding days and food consumption decreased, while growth per day increased. There was also an apparent correlation between higher serum titres and a decreased prevalence of pleuritis at slaughter in three of the herds.