Reproduction in Domestic Animals

348 JM Vazquez, J Roca, MA Gil, C Cuello, I Parrilla, I Caballero, JL Vazquez and EA Martı´nezbleeding as a result of the insertion of the DUI catheterobtained by the Australian group is difficult to explain ifwe take into account other researches where theincidence of bleeding during or after DUI was low ornon-existent (Martinez et al. 2001a, 2002, 2006; Dayet al. 2003; Rath et al. 2003; Roca et al. 2003; Vazquezet al. 2003; Bolarin et al. 2005a; Grossfeld et al. 2005;Wongtawan et al. 2006). In a recent trial performed on acommercial farm in Spain, we could detect blood on theDUI catheter after insemination in only 2 out of 95 sowsinseminated which was similar to that observed in sowsinseminated with the traditional AI method (1 out of95). Each of those three sows farrowed a high number ofpiglets (Martinez et al. 2006). More recently, similardata on bleeding have been obtained by our group usingDUI methodology (6 sows with blood out of 108) andstandard AI (4 sows with blood out of 114) with noinfluence on performance reproductive of the sows(unpublished data).While it seems clear that the presence of blood duringor after insemination does not exert a detrimental effecton fertility results after DUI, the contradictory results inrelation to the incidence of bleeding as a consequence ofthe insertion of a DUI catheter remain to be explained.Several factors could be implicated in the differencesobserved in relation to the bleeding phenomenon. First,it is evident that during the development of any newtechnology, problems during the period of training areexpected. Deep into the uterine horn technologyrequires more patience and skill when compared tostandard AI procedures. In addition, improper manipulationof the device when placing the catheter into theuterus could result in damage of the cervix and ⁄ orthe uterus. The device should always be inserted carefullyand not forced when some resistance is encountered.Although the DUI procedure can be performed safelyand quickly, a minimum period of training is necessaryin order to achieve optimal results. Second, the differencesmay be due to disparity between the commercialcatheters and the experimental prototype used in thepublished reports. While the experimental prototypeswere carefully hand-made, some abnormalities wereobserved in several parts of the DUI catheter in somebatches of the first commercial catheters constructed.This limitation has been solved by a later refinement ofthe DUI catheters carried out by a German company(Minitube, Tiefenbach, Germany). Currently, the incidenceof bleeding after the DUI procedure using thecurrent commercial DUI catheter (Minitube) is low andsimilar to that observed after the standard AI technique.In our first studies, using a fibre optic endoscope, avisible mark on the endometrium of the first uterinecurvature was visible in a high proportion of sows(Martinez et al. 2001a). Recently, Bathgate and coworkersperformed an experiment in order to examineendometrial trauma resulting from the DUI technique(Bathgate et al. 2007). In this experiment, five sows duefor slaughter were weaned at a time to match the onsetof oestrus with their arrival at the abattoir. Less than1 h prior to slaughter, the DUI catheter was inserted asif the sow was to be inseminated, without deposition ofthe semen. Immediately after slaughter, the entirereproductive tract was removed from each sow andtransported to the laboratory where the tracts weredissected and inspected for damage to the uterineendometrium. The authors observed slight damage tothe endometrial lining in all sows and that none of thesesows bled during or after the insemination. These resultsare in agreement with our previous observations usingthe endoscope (Martinez et al. 2001a). While in ourstudy the endometrial damage did not affect the fertilityof hormonally treated oestrous sows, the implications ofany damage to the reproductive tract of the sowsinduced by insertion of the DUI catheter needs to beconsidered, as suggested by Bathgate et al. (2007).Consequently, two experiments have been conductedby our group. In the first experiment (Bolarin et al.2005b), the effect on future fertility of DUI catheterinsertion into the uterine horn during deep intrauterineinsemination was evaluated. A total of 159 weaned sows(parity 2–8) were twice DUI-inseminated in a commercialfarm during 10 months with 1–2 · 10 9 frozenthawedspermatozoa. Ninety-nine sows (62.7%) werepregnant and 97 (61.0%) farrowed with a mean littersize of 9.6 ± 0.28. Reproductive data on pigs inseminatedby standard AI before and after DUI wererecorded and compared (Table 1). No differences(p > 0.05) were found in pregnancy and farrowingrates nor litter size for AI before and after DUI.Moreover, ‘not in pig’ rates were also similar. Fromthese results, we concluded that the insertion of the DUIcatheter into the uterine horn did not affect subsequentfertility of the sows.In the second experiment (Rodriguez-Vilar et al.2006), the effect of insertion of the DUI device into oneuterine horn on the reproductive performance ofmultiparous sows was evaluated. A total of 51 sowswere conventionally inseminated twice with cooledsemen (3 · 10 9 sperm ⁄ 100 ml doses) at 0 and 24 hafter onset of oestrus. At the time of the firstinsemination, the sows were randomly divided intotwo groups. In one group, a DUI device was insertedat the same time that conventional insemination wascarried out (DUI group). The remaining 23 sows wereonly conventionally inseminated (control group). Therewere no differences (p > 0.05) between the DUI andcontrol groups for pregnancy and farrowing rates orlitter size (Table 2). A supplementary study with ahigher number of sows (n = 186) offered similarresults (unpublished data). These results show thatthe insertion of the DUI catheter into the uterus doesnot affect the reproductive performance of multiparoussows.Table 1. Reproductive performance of sows traditionally inseminatedwith 3 · 10 9 fresh spermatozoa ⁄ 100 ml of extender before and afterthe use of the DUI procedure (from Bolarin et al. 2005b)ParameterStandard AIbefore DUI insertion(n = 159)Standard AIafter DUI insertion(n = 159)Pregnancy rate (%) 87.4 86.2Farrowing rate (%) 84.9 84.3Total piglets born11.1 ± 0.17 11.5 ± 0.15(mean ± SEM)Not in pig (%) 2.9 2.2Ó 2008 The Authors. Journal compilation Ó 2008 Blackwell Verlag