Evaluation of fertility and subfertility in adult alpacas and tuis using ultrasonography, endometrial cytology and bacterial isolation

The objective of this study was to compare the uterine health between fertile, sub-fertile alpacas and tuis using transrectal ultrasonography, endometrial cytology and bacterial isolation. A total 10 tuis (young mature females without breeding with average age of 1.5 years) and 20 adult alpacas of the Suri breed were used. In turn, the adult females were divided into two groups of 10 animals each according to their reproductive history: fertile group (parturition every year) and sub-fertile group (1 to 2 years without pregnancy). In all females, the thickness of the cervix and uterine horns was determined by transrectal ultrasonography. On the other hand, endometrial cytology and bacterial isolation were performed from samples obtained by uterine flushing. A Kruskal-Wallis and a Chi-square tests were used to compare ultrasonography and cytology groups. A greater thickness of the cervix and both uterine horns (p˂0,05) was observed in the fertile alpacas with respect to the sub-fertile and tuis. The percentage of PMN in tuis and sub-fertile alpacas was < 2%, while in fertile alpacas the percentage of PMN were: 6 animals with < 2% PMN, 2 animals with 2-5% PMN and two other alpacas with > 5% PMN. The bacteria isolated were: Bacillus lechiniformis and Escherichia coli in the three groups studied, Staphylococcus saprophyticus and Bacillus cereus in tuis and fertile alpacas, Staphylococcus aureus in tuis and sub-fertile, Bacillus spp. and Micrococcus spp. in fertile and sub-fertile alpacas, Bacillus lactic acid, Staphylococcus epidermidis and Citrobacter spp. in fertile alpacas, Enterococcus spp., Bacillus subtilis and Klebsiella spp. in sub-fertile and Enterobacter spp. in tuis. The low percentage of PMN in endometrial cytology in sub-fertile alpacas would indicate the absence of endometritis at the time of the study. However, the lower thickness of the cervix and uterine horns observed in sub-fertile alpacas suggest that it would be necessary to perform uterine biopsies in order to evaluate if there is any association between the thickness of the uterine wall and the presence of degenerative and/or inflammatory changes observed on histopathological examination.