Sperm production by rams is highly correlated with the testicular perimetre. This is why this criterion is one of the key ones when selecting rams for reproduction. The scrotal perimeter of rams varies with the season of the year, the age of the rams and throughout the period of utilization for reproduction. There is a 50 cm meassuring tape, with divisions of 1 cm, which allows assessing the scrotal perimeter at its widest part. It is fitted for either young male or adult rams, stablishing the minimum size and the recommended perimeter for any of these two types of rams.