Poor conception rates (too many barren ewes) are mostly due to sub-fertile rams, so being sure your rams will work is critical to a productive lambing.
Sperm production takes 49 days (7 weeks), so it takes that long for a ram to become fertile again after any problems.
Production can be disrupted by lameness (because inflammatory markers spread through the blood stream), fever (because sperm production is very temperature sensitive), epididymitis (infection of the epididymis which stores sperm within the scrotum), or scrotal abscesses or damage.
Successful sperm production happens at a temperature of 36C, this is maintained by the scrotum holding the testicles outside the body and being well supplied with sweat glands. But, hot sheep lie down to lose heat via the abdomen, which traps the testicles against the body and leads to the testicles overheating. This leads to production of less/abnormal sperm, which leads to poor fertility.
To prevent this, make sure rams are shorn before hot weather and provide shade. In addition, make sure rams are not too fat, as fat in the scrotum interferes with the cooling.
10 weeks pre tupping you should check rams are fit to work as described below:-
- Toes - lameness, footrot etc, arthritis
- Teeth - missing, molar abscess, over/under shot jaw
- Testicles - measure, firmness, lumps, 32cm ram lambs, 36cm shearlings/mature (and check penis)
- Tone (BCS) - 3.5-4
- Treat - vaccinations, parasites
To chat this through in more detail, have a chat with the farm team 01363 772860.