In the last 6-9 months we have been encouraging producers to get rams checked for soundness prior to joining time. This is not an expensive exercise and recommended to be carried out annually by someone with experience with testicle palpation. We are typically finding 10% of rams are unsound for joining. Reasons are due to lameness, poor body condition, lesions on testicles and soft and small testicles. There has been a recent shift to more rams with smaller testicles and of these the majority have been purchased as ram lambs.
Recommended minimum testicle weight is 200 gram to produce adequate sperm numbers. Almost all rams with SC less than 30cm will have testicles that weigh less than 200gm. 45% of rams with a SC of 30-32 cm have testicles less than 200g while rams with a SC greater than 32 cm, almost all testicles are more than 200 gram. Therefore ensure that the rams you buy have scrotal circumference greater than 32cm, without testicles of this size there is a good chance they will not get the job done.
Further to the actual performance of the ram, there are favourable correlations of SC with age of puberty, ovulation rate, twining rate and lifetime reproductive performance in female progeny.
To the right is a graph showing relationship between SC and testicular weight.
Andrew Whale BVBio/BVSc
Veterinary Consultant/Senior Partner
Mob: 0428 292 361
60 Portland Rd, Hamilton VIC, 3300
Ph: (03) 5572-1419 Fax: (03) 5572-1311