Use of a novel double uterine deposition artificial insemination technique using low concentrations of sperm in pigs R. Mozo-Martín a,⇑ , L. Gil a , C.F. Gómez-Rincón b , Y. Dahmani c , M. García-Tomás c , J.L. Úbeda c , J. Grandía d a Department of Animal Pathology, Obstetrics and Reproduction, Faculty of Veterinary Medicine, University of Zaragoza, Zaragoza 50013, Spain b University of San Jorge of Zaragoza, Zaragoza 50830, Spain c Department of Research and Development, Magapor SL Company, Zaragoza 50600, Spain d Technical Veterinary Department, Agrotest Control SL Company, Zaragoza 50600, Spain article info Article history: Accepted 7 November 2011 Keywords: Pig Artificial insemination Post-cervical insemination Double uterine deposition insemination Deep intrauterine insemination abstract Currently, the three most important non-surgical artificial insemination systems used in pigs are the con- ventional, the post-cervical (IUI), and the deep-intrauterine (DIUI) methods. In this study, a new system, termed double uterine deposition insemination (DUDI), which combines aspects of both IUI and DIUI, was evaluated. This method used a thinner, shorter and more flexible catheter than those normally used for DIUI and resulted in the deposition of semen post-cervically, approximately half-way along the uter- ine horn, thus potentially by-passing the threat of ‘unilateral’ insemination or pregnancy when using sperm of low concentration. The experiment was carried out over 8 weeks on a group of 166 sows, which were divided into seven groups, inseminated with semen of varying concentration, using the conven- tional system (control group) or by DUDI. There were no significant differences in fertility at day 35 post-insemination between the controls and the various DUDI sub-groups. Only sows inseminated with 500 million viable spermatozoa in a total of 30 mL of fluid using the DUDI system demonstrated decreased total litter sizes when compared to con- ventional insemination (P < 0.001). While conventional insemination normally uses 2.5–3.5 billion sperm, the findings of this study suggest that DUDI can be used under ‘field’ conditions with sperm con- centrations as low as 750 million spermatozoa in 50–30 mL without any detrimental effect on fertility or litter size. DUDI may provide a viable, robust alternative to IUI and DIUI, and has the potential to become incorporated into on-farm insemination systems. Ó 2011 Elsevier Ltd. All rights reserved. Introduction Artificial insemination (AI) has been successfully used in pigs for decades to improve animal health and maximise litter size. The procedure can be carried out in a variety of ways including ‘conventional’, intrauterine/post-cervical, and deep intrauterine insemination. Conventional AI was the first to be developed and is the most straightforward in application. Normally, some 2.5– 3.5 billion spermatozoa are inseminated in volumes of 80– 100 mL of extender via a simple catheter located at the distal cer- vix. Effective results have been achieved using as few as 1 billion spermatozoa/inseminating dose (Steverink et al., 1998; Watson and Behan, 2002), although under ‘field’ conditions, optimal out- comes are only achieved when 2.5 billion spermatozoa/dose are used (Alm et al., 2006). The use and economic benefits of intrauterine AI (IUI) in pigs, although first described in 1959 (Hancock, 1959), were not fully appreciated and adopted until relatively recently (Watson and Be- han, 2002). The technique is based on the deposition of semen in the cranial cervix, uterine body or at the proximal end of the uter- ine horns via a trans-cervical catheter. A difficulty in using this method is the challenge of catheter introduction posed by the cer- vical mucosal folds (Watson and Behan, 2002). Most commercial protocols advise that sows are inseminated with 1–1.5 billion sper- matozoa within 45–50 mL of fluid (Mozo-Martín, 2009, 2010). Good fertility and prolificacy has resulted from the use of 1 billion spermatozoa with post-cervical AI relative to doses of up to 3 bil- lion used in conventional insemination (Watson and Behan, 2002; Sumransap et al., 2007). However, under field conditions, a signif- icant loss of fertility was found using 1 billion spermatozoa (Wat- son and Behan, 2002; Rozeboom et al., 2004; Roberts and Bilkei, 2005), possibly due to deficiencies in the insemination procedure, such as in the oestrous synchronisation of the sows (Rozeboom et al., 2004; Garcia et al., 2007). Deep intrauterine AI (DIUI) is a non-surgical, trans-cervical technique that results in the placement of spermatozoa deep with- in the uterine horn. The DIUI system uses a guide catheter and an 1090-0233/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.tvjl.2011.11.007 ⇑ Corresponding author. Tel.: +34 645 848 578. E-mail address: 443533@unizar.es (R. Mozo-Martín). The Veterinary Journal 193 (2012) 251–256 Contents lists available at SciVerse ScienceDirect The Veterinary Journal journal homepage: www.elsevier.com/locate/tvjl