In the present work we present the main productive studies carried out to characterize ROA sheep (R+, Rasa Oviaragón®), ewes of the Rasa Aragonesa breed carrying in heterozygosity a natural genetic prolific variant found in 2007 (FecXR allele, BMP15 gene). Its effect on prolificacy leads to an increase of 0.35 lambs/lambing ewe when compared with non-carrier ewes, with an additive effect over the standard hormonal treatments used in farms. In artificially inseminated ewes, an increased fertility was also found in a set of farms (71.1 vs. 59.5 %; p