Technical Note: A new device for cervical insemination of sheep - design and field test.

Deep semen deposition, avoiding retrograde flow, lesions and stress, has proved to be very important in the success of sheep AI. The objective of the present study was to develop a new, suitable anti-retrograde flow device for sheep cervical AI (DARIO) that enables deep deposition of semen into the cervix without any modifications to the procedures currently used, and to compare the fertility, fecundity, and prolificacy rates between DARIO and a traditional catheter. Field tests were performed on 16 farms actively participating in the non-profit National Association of Rasa Aragonesa Breeders´ genetic selection scheme and where sheep management was similar. A total of 242 AI lots were considered, including 1,299 ewes; 126 lots (662 ewes) were inseminated using DARIO, and 116 lots (637 ewes) using a traditional commercially-available catheter (control group). Several factors affecting AI results were included in the model for mean comparison between DARIO and control groups (farm and ram as random factors; catheter, year and photoperiod as fixed effects; catheter × photoperiod interaction). The type of catheter had a significant effect on fertility ( < 0.01) and fecundity rates ( < 0.01) but no significant effect was detected on the prolificacy rate ( = 0.45). For fertility rate (percentage of ewes lambing after AI), means ± SE for DARIO and control groups were 59.44 ± 2.13% and 49.60 ± 2.48%, respectively; for fecundity rates, means ± SE for DARIO and control groups were 0.99 ± 0.04 and 0.82 ± 0.05 lambs/inseminated ewe, respectively, and, for prolificacy rates, means ± SE for DARIO and control groups were 1.68 ± 0.04 and 1.63 ± 0.04 lambs/ewe lambing, respectively. Fertility rate was greater in the decreasing photoperiod ( = 0.01). Significant effects were found for both year ( < 0.05) and farm ( < 0.01) on fertility, fecundity, and prolificacy rates. Neither ram nor catheter × photoperiod showed any significant effects on the variables investigated ( > 0.05). Overall, the use of DARIO instead of the traditional commercially-available catheter increased both fertility and fecundity rates; the marginal mean differences were 9.05 pregnant ewes per 100 inseminated and 0.15 lambs per inseminated ewe, respectively.