Effect of breed and storage temperature on the quality of boar semen

Abstract

Storage of boar semen for Artificial Insemination (AI) use in the Ugandan pig industry is challenging due to the susceptibility of the boar semen to cold shock and hot temperatures. When subjected to temperatures below the suggested critical temperature of 15℃ boar semen loses its viability. The aim of this study was to determine the effect of boar breed and storage temperature on semen quality. Four semen samples were collected from two boar breeds (Large-White and Camborough) and replicated thrice following the collecting calendar (Tuesdays, Thursdays and Tuesday). The samples were extended and stored at three temperatures: 4℃, 19℃ and 23℃ for 0, 1, 2 and 3 day(s). Semen analysis for motility, vitality, membrane integrity and pH were then evaluated microscopically. The data obtained were subjected to Analysis of Variance using GLM Procedure of GenStat ver.17. Means of significant difference were separated at 5% significant level. Boar breed did not significantly influence (p>0.05) the semen quality parameters studied. Meanwhile, storage temperature significantly (p = 0.001) decreased motility, vitality and membrane integrity of boar spermatozoa over the storage days. However, the semen pH was not significantly (p = 0.296) affected over the days of storage. Storage temperature of 19℃ performed best followed by 23℃ and 4℃ had the worst results. There was a strong and positive correlation between motility, vitality and membrane integrity and a low correlation with pH and other semen quality parameters. The slight reductions in pH were due to the reduced metabolic activity of the sperm cells under low temperatures with lack of oxygen. The drastic reduction in the at 4℃ semen quality percentages was attributed to the susceptibility of the boar semen to cold shock. Reductions at 19℃ and 23℃ were due to the increased metabolic wastes of the semen under these temperatures due to continued metabolic activities. Therefore, semen from both breeds would be suitable for the artificial insemination without compromising on the quality of the semen. Also, with the semen extender currently in use, boar semen could be stored at 19℃ up to the third day after collection and still be viable for artificial insemination. Emphasis should therefore be put on semen storage and transport containers for field insemination such that suitable temperatures are maintained to ensure boar semen viability.