A causal approach to understanding management factors, reproductive underperformance and reproductive infections in dairy cattle

Abstract

21The objective of this study was to investigate causal associations between cattle farms' 22 management practices and reproductive disorders (abortion, stillbirth, retention of placenta, 23 metritis). Besides, direct causal associations between farms' management and reproductive 24 infections (Chlamydia abortus, Coxiella burnetii, and Neospora caninum), reproductive 25 disorders and infections were also investigated in this study. As a secondary objective, 26 constraints that affect the production in cattle farms were examined. The study was carried out 27 in the north-western (Una-Sana), western (Canton 10) and central part (Central Bosnia Canton) 28 of Bosnia and Herzegovina. A total of 201 farms were selected for participation. A semi-29 structured questionnaire-based interview was conducted among farmers/managers from 30 January 1 st to August 31 st , 2015. The 40 questions were divided into three groups: socio-31 demographic, management, and information on reproductive performances in cattle. 32 Supplementary questions were asked about the perceived primary constraints of the production. 33 A multivariable mixed-effects logistic regression was used to screen management factors for 34 potential statistical influence. All investigated outcomes were associated with farms' 35 management. The final multivariable models were merged into a Structural Equation Model 36 (SEM). The causal model was then specified graphically. The SEM model showed that herds 37 that experienced abortions (OR=4.3) and stillbirth (OR=6.7) were associated with N. caninum 38 seropositivity. Also, herds that experienced retention of placenta were strongly associated with 39 the occurrence of metritis (OR=10.1). C. abortus and C. burnetii herd seropositivities were 40 mainly associated with environmental factors and contact with potential intermediate hosts. 41Our study demonstrated that management practices on dairy farms in Bosnia and Herzegovina 42 contributed to the occurrence of severe reproductive outcomes and reproductive infections. N. 43 caninum seems to be an infectious agent that substantially contributed to the reproductive 3 44 underperformance. Further we demonstrate the need for using causal models in understanding 45 complex relationships. 47Agriculture is one of the most vital sectors of economy for the countries in Western Balkan. 51Most of them have substantial share in the total state gross value added (GVA) ranging from 52 7.6% in Bosnia and Herzegovina (BH) to 20.1% in Albania. [1]. The situation in the agricultural 53 sector is gradually improving in most of Western Balkan countries, but there are still some 54 critical steps in reforming the agricultural policy and its harmonising with the EU standards. 55 Agriculture is especially important for the economic development of BH [2]. The government 56 of BH has committed to raising the little share (7.6%) of agriculture in the gross domestic 57 product (GDP) through the focused strategic approach to the sector [2]. To promote this 58 development, a new le...