The relation between mating activity of rams in pens and subsequent flock mating performance

Abstract

The serving activity of seven rams in one 20-minute pen mating test followed by two one-hour pen mating tests was recorded. The mating performance of each ram during a single-sire flock mating was subsequently monitored. Mean number of services in the two one-hour pen tests gave the best prediction of the number of ewes inseminated during flock mating (r = 0.88, P < 0.01). The number of services in the 20-minute test gave a poor prediction of the number of ewes inseminated (r = 0.30). The total number of services during the first 20-minutes of the two one-hour tests (2x20-minute tally), the number of services during the 20-minute test and the first 20 minutes of the first one-hour test (2 x 20-minute tally) and the number of services during the 20-minute test and the first 20 minutes of the two one-hour tests (3x20-minute tally) were only moderately correlated with number of ewes inseminated (r = 0.67, r = 0.47 and r = 0.64, respectively). These results explain why other workers, using combinations of 20-minute tests, have failed to demonstrate a relationship between pen mating tests and flock fertility. The results further show that a measure of the serving activity of rams in pens can be used to identify rams that are capable of mating large numbers of ewes, and that the development of a commercially applicable test is worthwhile.