Embryonic and Fetal Mortality Risk Factors in Dairy Cattle in the Mountainous and Forested Areas of Northwestern Tunisia

This study was conducted in 57 small farms located in mountainous and forest areas by the Office of Sylvo Pastoral Development North West of Tunisia (ODESYPANO), during the periods between 2007 and 2010. A total of 286 dairy cows were subjected to the approach adopted by the ODESYPANO. The dosages of progesterone (the day of insemination at 21-24 days post insemination), the pregnancy specific protein bovine (PSPB) in 30 to 35 days post insemination and rectal palpation at 60-90 days post first insemination allowed us to determine the effects of embryonic and fetal mortality. The average rate of embryonic and fetal mortality were 32.4% (n = 84), 19.9% (n = 51) and 9.4% (n = 24) respectively for Early Embryonic Mortality / No fertilization (EEMNF), Late Embryonic Mortality (LEM) and fetal mortality (FM). The EEMNF was not significantly influenced by breed, class of lactation number, calving season, suckling, the housing type, class of milk production, uterine, metabolic and breast diseases, the IBR, BVD and cyclicity profile. However, it is significantly influenced by parity (p = 0.04), body condition on the day of insemination (P = 0.001) and calving year (p = 0.003). The LEM depends on suckling (p = 0.01), uterine pathology (p = 0.01), scoring body condition on the day of insemination (P = 0.001) and post partum cyclicity profile (p = 0.001). For IBR and BVD, they are tangent to the level of significance (p = 0.05 for each disease). The FM varies significantly by breed ((p = 0.03) (FM rates are 14.0%, 10.2% and 3.3% respectively for Holstein, Brown Swiss and the local cross), the scoring of body condition on the day of insemination (P = 0.001) and metabolic diseases (p = 0.02). The attenuation rates of embryonic and fetal mortality in these small dairy herds could be obtained by properly detecting the estrus, encourage a resumption of normal cyclicity, by establishing an appropriate prophylactic and treatment measures and by ensuring an adequate body condition scoring at insemination period.