Epidemiology and risk factors of pyelonephritis in Israeli dairy cattle

Pyelonephritis epidemiology of dairy cows is not well understood, and the risk factors are ill defined. The primary objective of this study is to assess the risk of catheterization for urine sampling in dairy cattle. The secondary objectives are to describe the epidemiology and risk factors of pyelonephritis in Israeli dairy cattle. The research is a retrospective case control study conducted on Israeli dairy cows that calved during a seven years period in three commercial dairy herds treated by the ambulatory clinic of the Koret school of Veterinary Medicine. Seven-four cases of pyelonephritis (incidence=1.05%) were diagnosed during the study period. Forty percent of the cases were diagnosed during the first month of lactation; parity (Odds Ratio (OR) for 2^nd and 3^rd lactation or more cow = 2.381 and 2.891, respectively), twin calving, endometritis and ketosis (OR=2.927, 1.693 and 2.206, respectively) were associated with pyelonephritis in the study population. Urethral catheterization was not significantly associated with pyelonephritis. Forty-four urine samples were cultured. Escherichia coli was the most prevalent bacteria isolated from urine (30 cases; 65.9%). The second most prevalent bacteria were Proteus Mirabilis (6 cases; 13.6%). It was concluded that pyelonephritis of dairy cows is associated with calving diseases. The risk of contracting pyelonephritis increases with age. Urethral catheterization was not associated with increased pyelonephritis risk. The initial treatment of pyelonephritis in dairy cows should be effective against E.coli.