Epidemiology of toe tip necrosis syndrome (TTNS) of North American feedlot cattle.

Toe Tip Necrosis Syndrome (TTNS) is predominantly a hind limb lameness of feedlot cattle that develops early in the feeding period. Retrospective analyses of feedlot health records were conducted in order to describe the epidemiology of the disease at the level of the individual animal, lot, and feedyard. Analysis of 1904 lots (cohorts of > 100 head) of cattle, from 48 feedyards, found that TTNS occurred sporadically, but clustered by both lots and feedyards. Only 3.8% of lots had ≥ 1 case of TTNS; however, 26.4% of these lots were associated with 1 feedyard. Analysis of 702 cases of TTNS found that the disease clusters early in the feeding period; the mean (median; range) number of days on feed at death was 42.3 d (27.0 d; 4 to 302 d). The disease occurred in all months of the year and affected calves, yearlings, steers, and heifers. It was equivocal as to whether the source of the animals was associated with how quickly they died of TTNS in the feedyard.