The ram is the most important member of the flock, yet he does not always get the attention he deserves. Good ram management can determine the success of your breeding program and ensure a profitable lamb crop.
Sperm production in rams takes 49 days, therefore it is important to remember that you will not see the effects of any management changes for almost 7-8 weeks. You’ll want to ensure rams are well looked after in the two month period leading up to the breeding season as it will have a direct effect on the quality of sperm and fertility of the ram.
Testicle size is a good indicator of a ram’s sperm producing ability, which can be assessed using scrotal circumference. Large testicles are associated with higher sperm production and sexual drive. Additionally, checking the tail of the epididymis can give you an estimate of the level of sperm reserves in rams. A large, firm epididymis is an indication of good reserves, while a small, soft tail indicates the opposite. A ram’s testicular size, sperm production, and mating capacity will vary throughout the year, being highest during the normal fall breeding season.
Nutrition also plays a large part in ram testicle size and sperm production. Improving the intake of protein and energy during the two month period leading up to the breeding season can dramatically increase testicle size and sperm production. Consider body condition scoring your rams and aim to have them at a score of 3-3.5 at breeding. Rams with a very low or very high body condition score (BCS) demonstrate poor reproductive performance due to reduced sperm motility and sexual drive.
A 2010 study by Maurya demonstrated a 3-5cm difference in scrotal circumference of rams with a BCS of 2.5 compared to rams with a BCS of 3 to 4. Additionally, rams with a BCS of 2.5 produced 0.46mL less sperm and motility was 11% lower than rams with a BCS of 3. The study also looked at sexual behavior and showed that rams with a BCS of 2.5 had reduced sexual parameters such as reaction time, latency period, time taken for ejaculation, and number of mounts.
Good ram management doesn’t have to be costly or labour intensive. A ram with high conception and lambing rates can have a healthy impact on your profits.
Measuring Scrotal Circumference:
Push the testes down in the scrotum and tighten the scrotal tape (not a measuring tape) at the widest part. The scrotal tape is metal and when tightened the measurement can be visualized. It needs to be snug to get an accurate measure.
The scrotal circumference should meet minimum standards for a mature ram:
>70 kg → > 30 cm SC
>110 Kg → > 36 cm SC
Palpating the Epididymis:
Palpate the testes with two hands, one on each side at the base of the scrotum. Feel the spermatic cords between the thumb and fingers, gradually move down to the epididymis. A comparison between the testes can be made by simultaneously using one hand on each side. The epididymides should be symmetrical and soft with no lumps. A large, firm epididymis is an indication of good reserves, while a small, soft tail indicates the opposite.
Where to Buy:
Scrotal tapes can be ordered online at either of the following sites
References:
Maurya VP, Sejian V, Kumar D, Naqvi SMK 2010. Effect of induced body condition score differences on sexual behavior, scrotal measurements, semen attributes and endocrine responses in Malpura rams under hot semi-arid environment. Journal of Animal Physiology and Animal Nutrition 94: e308–e317.
