Abstract
BACKGROUND: Cattle abortion, which may be caused by different infectious agents, harms milk and meat production, animal health, and ultimately rural economies. Despite the existence of a national control program for cattle brucellosis since 1995, abortion remains a major concern for cattle breeders in Algeria even among officially recognized cattle Brucellosis-free herds. The objective of this study is to investigate i: the abortion rate among officially recognized cattle Brucellosis-free herds, ii: the seroprevalence of some abortive infectious agents within cattle Brucellosis-free herds, iii: evaluate the abortion risk factors associated with the seropositivity of the investigated abortive agents among brucellosis cattle-free herds. RESULTS: The present study reveals an abortion rate at the herd and the individual level of 47, 36% (20/38) and 29, 06% (50/172) respectively. Herd seroprevalences were as follows: neosporosis (31,57%), toxoplasmosis (28,94%); chlamydiosis (Chlamidophila abortus) (15,78% ); Q fever (Coxiella burnetii) (47,36%); Bovine viral diarrhea (BVD) (60,52%) and infectious bovine rinotracheitis (IBR) (42,10%). The risk factor analysis using a multivariable logistic regression model at the herd level showed that seropositivity to neosporosis (OR = 1, 11, CI: [0,85 - 1,19]); toxoplasmosis (OR = 1,95, CI: [1,22 - 2,84]); IBR (OR = 1,78, CI: [1,59 - 2,79]); BVD (OR = 1,65, CI: [1,86 - 3,43]); Q fever (OR = 1,51, CI: [1,42 - 2,53]) is a risk factor for abortion. Additionally, our findings reveal that the presence of co-infection is also a risk factor for abortion among Algerian Brucellosis-free herds. The risk for abortion at the herd level was 1,41 times higher for double and triple-infected herds and 1,65 times higher for quintuple-infected herds compared to negative. Moreover, managerial factors, such as hygiene practices on farms, the presence of primiparous cows, and mixed breeding livestock, were identified as additional risk factors for abortion. CONCLUSION: Based on these results, particular attention should be given to the studied abortive agents to strengthen the prevention and control plan. Furthermore, establishing some preventive measures such as quarantine and biosecurity could help reduce infections in dairy farms.