COMPETITIVE ABILITY OF RAMS SELECTED FOR HIGH AND LOW-LEVELS OF SEXUAL PERFORMANCE

The objective of this study was to determine any differences in the co mpetitive ability of rams differing in levels of sexual performance. T wenty sexually experienced Targhee-type rams were pre-selected from a population of 95 males for exhibiting relatively high and low ejaculat ion rates when individually exposed to oestrous ewes for 30 min. Each of 10 high performers (HP) were paired with each of 10 low performers (LP) on three occasions when competing for food (after food deprivatio n) and twice when competing for an oestrous female. Tests were 5 min i n duration. Food-deprived HP and LP rams were equally aggressive when competing for a source of food that could only be accessed by one ram at a rime. Time of feeding by HP and LP rams did not differ. HP rams s pent more time with the oestrous ewe and attained move mounts in a gre ater number of pairings than LP rams even though HP and LP rams did no t differ in number of successful agonistic interactions (active displa cements and successful defences) when competing for the ewe. It was co ncluded that HP and LP rams, taken as groups, do not differ in their b asic competitive ability and that the greater mating success of HP ram s can be explained by their higher levels of libido.