Detecting asymptomatic rams infected with Mycoplasma agalactiae in ovine artificial insemination centers

Mycoplasma agalactiae (Ma) is the main causative agent of ovine contagious agalactia, which is a serious disease of small ruminants. In endemic areas, its most common clinical situation consists of chronically infected herds, and asymptomatic infected individuals represent an epidemiological risk regarding the transmission of this disease. The aim of this work was to detect the presence of asymptomatic rams infected with Ma in different artificial insemination centers, and to determine the most effective way to identify these individuals so as to implement adequate surveillance protocols. For this purpose, 215 rams and 14 teaser sheep were sampled taking auricular, nasal, and vaginal swabs and serum samples. In addition, ejaculates from 147 rams were analyzed. These samples were subjected to specific culture and molecular techniques to isolate and identify mycoplasmas, and to a serological test to detect antibodies against Ma. Mycoplasma agalactiae was detected in 47 (4.4%) of the 1077 samples analyzed, and also one individual resulted seropositive. Thus, 37 (17.2%) of the 215 studied rams were infected with Ma. The specimens which proportionally yielded the greatest number of positive results for this pathogen were semen samples (13.6%), followed by nasal swabs (5.8%). In contrast, the sampling of the external auricular canal and the serological analyses resulted insufficient to effectively detect infected individuals. Asymptomatic rams infected with Ma were detected in all the analyzed artificial insemination centers, highlighting the need to implement adequate surveillance protocols to prevent the presence of these individuals in these centers, reducing the risk of transmitting contagious agalactia.