EVALUATION OF BREED AS A RISK FACTOR FOR ATRESIA COLI IN CATTLE

Systematic review of published cases and a hospital-based case-control study were completed to evaluate breed as a risk factor for atresia c oli in cattle. Systematic review of 37 published studies indicated tha t atresia coli has been diagnosed in 10 cattle breeds and 12 countries , with the marked preponderance of cases occurring in Holstein-Friesia n calves (485/514 cases, 94%). Epidemiologic analysis based on 28,373 cattle < 2 mo of age admitted to North American veterinary schools bet ween 1964 and 1993 identified 291 cases of atresia coli in 13 breeds, with the marked preponderance of cases occurring in Holstein-Friesian calves (228/291, 78%). Holstein-Friesian cattle were at significantly greater risk for the condition than all other dairy cattle breeds (cru de odds ratio 4.55, P < 0.0001) and all other cattle breeds (crude odd s ratio 7.12, P < 0.0001), whereas there was no difference in the odds ratio between dairy cattle (not Holstein-Friesian) and beef cattle (c rude odds ratio 1.68, P = 0.11). Atresia coli probably occurs secondar y to vascular insufficiency of the developing colon. Holstein-Friesian cattle may be genetically predisposed to atresia coli, possibly becau se their developing colon grows at a faster rate and/or to a greater e xtent than that in other cattle breeds. Early or vigorous palpation pe r rectum of the amniotic vesicle appears to increase the risk of atres ia coli in a genetically predisposed fetus, probably through palpation -induced damage to the developing colonic vasculature. (C) 1997 by Els evier Science Inc.