The sheep industry is about 30 years behind the cattle industry when it comes to fertility testing.
That was the message Three Hills veterinarian Kathy Parker delivered to the recent Ultimate Sheep Seminar, presented by the Battle River Research Group.
Interest in semen testing rams has only started to pick up because of the influx of producers with cattle-breeding experience, said Parker, part of a team studying ram fertility and trying to increase awareness of benefits of fertility testing in improving flock productivity.
Most of the research is based on emulating long-established cattle-breeding practices.
Read Also
Mosquito-borne virus could be devastating to sheep breeding operations
Cache Valley virus, a mosquito-borne disease that infects small ruminants, could be a devastating hit to small operations.
“I was appalled and then I was embarrassed that we hadn’t done this sooner, so we’re taking this on as a challenge,” said Parker.
Rams need be examined and rigorously culled – as cattle producers do with bulls – in order to boost flock fertility. This includes checking for a treatable condition called seminal vesiculitis (an inflammation of the glands used to propel sperm during ejaculation) and culling rams for short penises, missing epididymis or inadequate scrotal circumference.
“When you’re culling rams based on scrotal circumference, the big deal is that he has no capacity,” said Parker. “He may have the best semen in the world, but he has no capacity.”
Not only are rams with inadequate scrotal circumference unable to sire a large flock, they produce poor offspring.
“Bulls with limited scrotal circumference begat females with limited ovarian capacity,” said Parker. “They burn out and were open by the time they were six. There is a pretty direct link between scrotal circumference and female fertility and that’s long term.
“You have to have a longer-term vision and wait for the females, but it does definitely happen.”
Parker said some breeds are more susceptible to this condition but she also warned it is affected by seasonality. Young rams may improve their scrotal circumference by about five centimetres between May and August, said Parker.
“If they have good semen, but are a little small in May, you might want to hang on to them because they should improve by the time breeding season comes,” she said.
Parker is part of a team which includes representatives from Alberta Agriculture, the Alberta Lamb Producers and the Western College of Veterinary Medicine. They will be holding producer workshops on how to properly measure scrotal circumference. They’ve also created a ram-breeding soundness evaluation report which rates rams based on their age, body condition, sex drive, mating ability, semen quality, and physiological soundness.
The worksheet, which could eventually be used nationally, has a chart which lists the ideal scrotal circumference of rams based on their age.
“If they’re anything less than satisfactory, they fail,” she said. The rams also need to have satisfactory sperm motility and morphology. If any of these standards are not met, the rams are deemed unfit for breeding.
Most people do not semen test their rams even though semen testing of bulls is standard. Rams should be semen tested about 45 days before breeding. Semen testing can be done by most veterinarians. Producer education and information will be key to the study and the uptake of the initiative, said Parker.
———
“There is a pretty direct link between scrotal circumference and female fertility and that’s long term.”
DR. KATHY PARKER
VETERINARIAN, THREE HILLS
