How an annual ram MOT can help optimise flock performance
© Tim Scrivener Successive heatwaves this summer could have a lasting effect on tup fertility well into September. While a tup can recover its semen quality six weeks after experiencing high temperatures, the only way to find out for certain is to get a vet test before breeding begins.
See also: Benefits of annual testing for bull and ram fertility
Testicles are designed by nature to hang outside the body to remain cooler, says vet Maarten Boers from The Livestock Partnership in West Sussex. But they are still sensitive to high temperatures – whether caused by heatwaves or an infection. “So a hot August can affect semen quality,” he stresses.
However, Maarten advises that all rams should be tested before breeding every year – not just new purchases or following extreme weather conditions.
A detailed physical examination (including teeth, feet and body condition) together with a semen test will establish whether problems are long term or temporary.
Multiple tups will not make up for poor fertility
For those sheep farmers who think they can reduce the risk of poor fertility by operating multiple tups in mobs, the message is clear: it does not work. Older, bigger tups dominate the group and stop the younger ones from mating, he says.
The older tups are also more likely to be the ones that are infertile, he points out.
“Subfertile tups can be more of a problem because it is a hidden problem that can do damage [to flock performance] over many years,” he adds.
There are no outward signs that an otherwise healthy-looking ram has poor semen quality. Even a subfertile or an infertile tup has a libido and can mark ewes, says Maarten. Fertility problems only become obvious at scanning when the result is lower-than-expected pregnancy rates (which can drop 20% in the first cycle), or more empty ewes.
Farm facts: Tottington Manor Farm, West Sussex
- Runs 850-1,000 breeding ewes – Romney Aberfields and Lleyn-crosses
- 22 tups: Charollais and Texel used as terminal sires; Lleyns and Logies for replacements
- 175 ewe replacements reared annually
- All progeny reared and sold direct to local butcher’s shops
- 16ha of barley for feed plus pasture of varying acreages in rental agreements
- 55 Sussex suckler cows; pure Sussex bulls finished at 14 months
© Tim Scrivener
Reasons for failing a physical check
He usually does pre-breeding fertility examinations four to six weeks before tups are needed. He believes that up to two in 10 tups he tests would be infertile, and palpating the testes is usually the first signal that something is wrong.
They should be of even size (up to 10% difference between the two is allowed) and at least 30cm in circumference, neither enlarged nor underdeveloped. “They should feel like a nice, strong bicep [muscle], not rock hard or soft,” he says.
Poor teeth and bad feet are the biggest reasons for failing a physical check. This is usually owing to a lack of routine care when rams are used for a few weeks a year, then turned out and forgotten. Combined with less grazing time during mating, however, these issues lead to rapid body condition loss.
“A tup serving 12 females a day spends the day chasing ewes and only grazes for a fraction of the normal time. He may have good condition at the start, but with only a couple of hours’ grazing every day, he will lose it too fast. And this affects his sperm production and motility,” says Maarten, who emphasises that top-quality grazing is essential to optimise both sperm production and ewe ovulation.
© Tim Scrivener
Cost of lost production
He suspects many sheep farmers still do not have breeding tups physically checked and semen tested every year because of perceptions about the cost and benefit. Yet he says it could lengthen the productive lifespan of a ram to six to eight years.
“See it like an annual MOT for your car – so much can happen in a year. Tups are at their most fertile at two to six years of age, but a lot happens in between: disease, management or a neglected foot infection that leads to an abscess in the testes,” he says.
Comparing the cost with the purchase price of a commercial ram (at £600-£1,200), Maarten thinks a pre-breeding and fertility examination at £20-£25 is not a big outlay. And it must be judged against the risk and cost of having fewer (or no) lambs born.
Case study: Tottington Manor Farm, Henfield, West Sussex
Paul Starley buys five or six new rams each September for his flock based near Henfield, West Sussex. Yet every one of the 22 tups he stocks at Tottington Manor Farm is given an annual check for physical health and semen quality before breeding.
It is an afternoon’s work for Paul and his vet, Maarten Boers of The Livestock Partnership.
“We do 22 tups in about three-and-a-half hours, just in the race, and I turn them over for the vet to check. He semen tests each one, checks testicle circumference, and gives them a full health check,” says Paul.
He synchronises 100 ewes to lamb indoors in early January; a further 150 ewes are bred to lamb inside in March, with the rest of the flock lambing outdoors in April. Maternal breeds are used on 75% of the flock to give plenty of choice over replacement ewe lambs and the rest are bred to terminal sires.
Shearling tups are bought in September and put to work the following year, from 1 August, with the early lambers. Some tups work twice, going back in with ewes in November.
When he buys replacement tups, Paul will travel to Builth for the sales, or to local markets at Hailsham in Sussex or Ashford in Kent. Logie rams are bought unseen, “but you know what you are getting”.
He normally likes to buy two or three tups from one farm. “It’s handy if they come from the same place and have been kept together, as it avoids fighting,” he explains.
Fertility checks timed to allow for culling and replacement
Every new ram is given an MOT by the vet once Paul has the ram home. They are tested again in July before they are used.
“If they are infertile, I have time to cull and replace the tup. The semen is tested under the microscope on farm, so the results are available straight away,” he says.
“I’ve never had a fertility problem with a newly bought ram – it’s usually an older one and it’s probably because of age.”
But even when a new ram has passed his checks with flying colours, Paul still has each one tested annually thereafter because “things change year by year”. “If you find one infertile tup, that pays for the test,” he says.
“If I have three rams to 100 ewes, an infertile tup suddenly makes it two rams to 100 ewes, and when one goes round a second time, it prolongs lambing. And if a ram is infertile, why would you want to put it with your ewes?”