Frequency of Boar Ejaculate Collection and its Influence on Semen Quality, Pregnancy Rate and Litter Size

Abstract

FrangeI R., T. Gider, M. Kosec: Frequency of Boar Ejaculate Collection: its Influence on Semen Quality, Pregnancy Rate and Litter Size. Acta Vet. Brno 2005, 74: 265-273. The aim of this study was to determine the best collection frequency for boar ejaculate, based on semen quality, pregnancy rate and litter size. Over a period of 7 months, 480 ejaculates were obtained, at successive collection frequencies of one, two, three and seven times per week, from 12 mature boars of line 54. For each ejaculate, the volume, progressive motility, spermatozoa concentration, sperm morphology and total number of spermatozoa were determined. Two commercial semen extenders, Beltsville Thawing Solution and Merck, were used for semen dilution and preservation. Smaller ejaculate volumes (P < 0.05), lower sperm concentrations (P < 0.05), and lower total sperm counts per ejaculate (P < 0.05) were obtained at collection frequencies of 7 and 3 than at 2 and 1 times per week. Significantly lower progressive sperm motilities at 7 than at 3, 2 and 1 times per week were observed. 1586 sows were inseminated with semen obtained at the four collection frequencies. The conception in sows was highest when inseminated with semen collected once per week and was significantly (P < 0.05) lower when collected 7 times per week than at the other three collection frequencies. The number of delivered piglets was also highest in sows inseminated with semen collected once per week and significantly(P < 0.05) higher than at collection frequencies of 2 and 3 per week. No significant differences in the semen quality parameters measured or in pregnancy rate were found when using either of the two commercial preservation extenders. These results indicate that the sperm quality decreases with increasing collection frequency and is most pronounced at the collection frequency 7 × per week. Taking into account the fertility rate and litter size, together with the number of semen doses obtained per week, the most suitable ejaculate collection frequency in mature boars of line 54 is two or three times per week.