10 POSTCERVICAL INSEMINATION OF SOWS WITH REDUCED SPERM NUMBERS IN FIELD CONDITIONS

Abstract

In the current procedures for AI in pigs, billions of spermatozoa are used (2.5–4.0 × 109 spermatozoa per insemination) in a large volume of liquid (70–100 mL), which is deposited in the cervix at the moment of AI. Approximately 90% of the spermatozoa inseminated cannot be recovered from the uterus at 2 h after AI (Viring S et al. 1980 Acta Vet. Scand. 21, 145–149). Several technical methods are used in the pig production industry for semen application using AI. To reduce the number of spermatozoa, several methods have been developed. The present study was performed to evaluate the reproductive effects under field conditions of postcervical AI (post-CAI) in southeast Spain with multiparous sows. In total, 509 sows were inseminated and divided in 3 groups: sows in the first group were inseminated using cervical AI (CAI, control group) with 3 × 109 spermatozoa in 80 mL of extender (group 1, n = 168); sows in the second group were inseminated by post-CAI using 1.5 × 109 spermatozoa in 40 mL of extender (group 2, n = 175); and sows in the third group were inseminated by post-CAI but using 1 × 109 spermatozoa in 26 mL of extender (group 3, n = 166). The catheter used for post-CAI consisted of a conventional AI catheter with an additional inner catheter that could extend past the catheter tip (Soft & Quick®, Import-Vet, Barcelona, Spain). Day 28 of pregnancy rates, farrowing rates, total pigs born, total live piglets, and stillborns were evaluated. Data were analyzed by ANOVA. Pregnancy and farrowing rates after post-CAI with 1.5 × 109 or 1 × 109 spermatozoa did not differ from those of the control group (group 1: 87.50%; group 2: 88.57%; group 3: 86.14%; P = 0.367). The number of spermatozoa inseminated did not significantly affect the number of live (12.27 ± 4.99; 12.18 ± 5.20; 12.64 ± 5.31; P = 0.946) or stillborn pigs (1.60 ± 1.79; 1.80 ± 2.27; 1.78 ± 1.84; P = 0.386) or the total number of piglets born (13.87 ± 5.39; 14.02 ± 5.75; 14.42 ± 5.65; P = 0.865). The present study shows that post-CAI with a low number of sperm cells does not negatively influence the reproductive parameters of multiparous sows compared with conventional AI. In conclusion, post-CAI in sows is simple, effective, and safe, and allows the sperm dose to be reduced to one billion spermatozoa.