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This investigation was conducted to study boar culling patterns in swine breeding herds. Data were obtained from 84 swine breeding herds and included 440 boars that were culled. Each producer was involved for 12 consecutive months, and recorded every boar that was removed from the herd, the date, and the reason for culling. The annual culling rate for the 84 farms averaged 59.4% +/- 6.4 (SEM). The correlation coefficient between boar and sow culling was 0.52 (p0.0001). Removal was the result of being overweight (47%), reproductive problems (18%), leg problems (12%), death (7%), and other diseases (4%). From the annual culling rate, the average breeding life of boars was estimated at 20 months. From this study, we concluded that the annual culling rate for boars in commercial herds was high and related to several different factors.

The purpose of this study was to compare four different techniques that may be used to assess the prevalence or severity of enzootic pneumonia in a swine herd. These techniques included: 1) assessing the percentage of lung involved and calculating a mean percentage and standard deviation for each herd, 2) counting the number of lungs in the herd sample that have greater than a predetermined amount of pneumonia and calculating the prevalence of the sample thus affected, 3) scoring only the lung from each herd sample that was maximally affected by pneumonia, and 4) allocating lungs to categories depending on the approximate extent of pneumonia. Five hundred and sixty pigs from 41 different swine herds in southern Minnesota were examined at slaughter and lungs were evaluated for the extent of pneumonia that was macroscopically visible.The mean percentage of pneumonia for a herd was positively and highly correlated with the standard deviation of that herd (r = +0.914; p0.0001), the prevalence of pigs having/=5% lung involved with pneumonia in that herd (r = +0.946; p0.0001) and with the percentage of lung that was observed to be the maximally affected lung in each corresponding herd (r = +0.940; p0.001).The most informative procedure was assessing the percentage of lung involved and calculating a mean for the herd sample. Allocating lungs to categories based on approximate severity of pneumonia was less precise and more difficult to interpret. Assessing the prevalence of affected lungs, or evaluating the maximally affected lung was less time consuming and equally as informative for a herd-based indicator, as scoring the percentage of each lung and calculating a mean.

Four hundred and sixty-two pigs from 37 herds were examined at slaughter for the presence and extent of turbinate atrophy and pneumonia. Turbinate atrophy was scored by measuring the mm space between the turbinate bone and the floor of the nasal cavity on both sides of the nasal septum. The total percentage of pneumonic involvement for each lung was evaluated by scoring the percentage of each lobe that was consolidated.There was a low, positive correlation between individual scores of turbinate atrophy and the associated percentage of lung involved with pneumonia (r = + 0.177; p0.001). There was a postive correlation between the herd mean turbinate atrophy score and the herd mean percentage pneumonia score (r = + 0.515; p = 0.001).The age at slaughter was known for 95 pigs from four herds and was not significantly correlated with the mm of turbinate atrophy, or the percentage of pneumonia.