Edward Dinger won numerous sheep industry awards during a 45-year career breeding Coopworths near Cambridge. Now retired, but still with a keen interest in ovine genetics and in particular facial eczema, Andrew Swallow asks what he sees as the challenges for breeders today and in future.
Sheep breeders and their societies need to work together more nationally, if not internationally, for the greater good of the industry. Only by doing that will genetics overcome some of the more challenging issues the sector faces, a retiring multi-award-winning breeder says.
Edward Dinger, 78, spent a lifetime selecting Coopworths to be facial eczema tolerant while maintaining the other fundamental traits for a productive sheep. Despite his flock becoming recognised as being industry leading for FE tolerance, he still believes more could, and should be done to combat this devastating disease.
But it’s not just for FE resistance that he believes breeders need greater collaboration to spur progress, but in all aspects of sheep meat and wool production. More research targeting productive traits and traits important to consumers is needed across the board.
“The three maternal breeds [Romney, Perendale and Coopworth] in particular have to come together,” he told Country-Wide magazine.
“The trend to composites, now the second largest group in the New Zealand flock after Romneys, should have been a step in the right direction but “it’s not unified and everyone is doing their own thing.”
Ram breeders’ collective focus should be on the things most sheep farmers want in their ewes: a low-input animal requiring no drenching, with sound feet and mouth, that’s efficient, long-lived, doesn’t need dagging and possibly not even docking/tailing, and, of course, FE tolerant.
“But these things are seldom combined in one sheep, let alone a whole flock, which is why we need a combined effort, nationally.”
Given the “shameful” decline in Government-funded research and research institutions, epitomised by AgResearch’s once world-leading Ruakura Research Station, Dinger says the initiative has to come from within, from breeders themselves. Breed societies must work together on a strategy to breed such ewes, seeking to combine the best commercial traits from all breeds.
Without greater cross-breed collaboration, and in the face of competition from alternative proteins, he believes sheep meat could easily go the same way as wool went.
He says 25 years ago coarse wool had little competition for carpets and furnishings. Now, thanks to huge budgets and ruthless advertising campaigns, synthetic fibre dominates the market.
“Synthetic meat could do the same… Only together will the sheep industry be able to face the threat of a world-wide demand for synthetic sheep meat.”
Finns a mistake
One area Dinger doesn’t believe needs more breeding effort, at least, not on most farms, is fertility. The reason some farms don’t get the lambing percentage they’d like is down to management and other challenges, rather than any inherent genetic limit on fertility.
He says fed well, and without high FE or parasite challenges, most ewes of most breeds will rear twins. Adding more fertile genetics risks more triplets and quads which are not only more time-consuming, hence less efficient for the farmer, but due to higher death rates, less acceptable to the consumer.
“One year we did 201% and it was a nightmare. We had far too many triplets.”
Consequently, he believes Finn genetics have probably done more harm than good to the industry. They should never have been introduced, whereas East Friesians had enough fertility and boosted milk production, and hence weaning weights, not to mention the now burgeoning sheep milk industry.
Dinger says how useful more recent introductions such as the Beltex will be remains to be seen. The meat yield attributes are appealing but lambing difficulties in purebred lines must be overcome for NZ systems. How Texels, which are routinely lambed by caesarean section on some studs in their native Netherlands, have been adapted and integrated into NZ breeds and systems possibly sets a precedent.
“We need easy-care sheep.”
It’s what first attracted him to the Coopworth, their easy lambing.
“I didn’t lamb a sheep for 20 years.”
But he puts most of the improvement in the performance of his 2000-ewe flock down to selecting for FE tolerance (see following article). It went from 135% lambing in about 1990 to an average of 170% with 4.5kg heavier lambs at weaning and 1.2kg more wool/year 20 years later,
His ideal would be a ewe that weans twin, works-ready lambs, year after year. But in chasing bigger lambs at weaning, one eye has to be kept on ewe size to maintain efficiency, especially with sheep flocks increasingly run on more marginal hill and steep land.
When he sold the bulk of his Coopworth flock, the heaviest were just over 80kg with an average of 67kg. Well-fed and empty (not pregnant), 65kg would be his target.
That shift to hill country is another reason to avoid triplet-prone genetics, as lambing on such country exacerbates losses, and not just in bearings, he adds.
“Triplet-rearing ewes also need to be fed like dairy cows and on steeper hill country that’s neither practical nor feasible.”
Genetic technologies will definitely speed breeding progress, he acknowledges, but that doesn’t remove the need for cross-breed collaboration. Beef + Lamb NZ Genetics is a positive development, but Government should boost and restructure its research funding so science bodies co-operate, rather than compete.
Despite the importance of agriculture to NZ as a nation, agricultural research funding here as a percentage of GDP is way below many other nations’, he notes.
“We spend nothing on it, by comparison. We will be overhauled by other countries and it will take donkeys’ years to catch up again.”
Farmers’ vote in 2009 to terminate the wool levy, was “understandable but disappointing” because it ended all research into wool Dinger says.
“We threw the baby out with the bath water: research is the answer [to strong wool’s woes] and we do next to none.”
Marketing efforts alone are unlikely to succeed given the strength of the competition, he adds.
“These huge chemical companies that produce the synthetic fibres have very deep pockets.”
He admits his own breeding efforts didn’t focus on wool, other than removing any progeny with obvious defects. “I liked my sheep to be uniform in look and not too fine or coarse, but I never found wool that interesting-also, the price of wool’s been in decline since 1952”.
Genetics best for fighting FE
- Key points:
- Impact widely underestimated.
- Sub-clinical cases missed in low spore seasons.
- Warming climate could spread risk area.
- High heritability tolerant genetics available.
- Still many unknowns – more research needed.
Unsurprisingly, after a lifetime breeding sheep to combat it, Edward Dinger says genetic tolerance is the best solution to facial eczema.
Effective though dosing with zinc is, it can be difficult and time consuming to do effectively and should be a last resort, he believes. It also tends to be used only in seasons when it’s recognised FE is likely due to elevated spore counts, but there’s a sub-clinical drag on production in FE prone areas every year.
“If you took all the subclinical cases out you’d probably get 15-20% better lambing percentage.”
A tolerant flock won’t be affected in non-epidemic years, and when spore counts do spike in an epidemic year, zinc treatment and/or grazing management can be used to boost protection. Having some FE safe forages, such as brassica, chicory, plantain or clover available in FE prone areas is a sensible precaution.
“It’s a very nasty strain we have here in NZ and in epidemic years even the most tolerant flocks are affected; in other places it’s not nearly so bad,” he notes.
Awareness of the disease, and interest in tolerant genetics, leaps in years when nights are over 12C, moist conditions and abundant pasture litter favour development of the toxin-producing fungus.
“Remove one of those things and you don’t have a problem.”
To select rams with FE tolerance they’re dosed with the toxin the pasture fungus produces – sporidesmin – then blood tested for the enzyme gamma glutamyl transferase (GGT) three weeks later. The higher the GGT, the greater the liver damage and the less FE-tolerant the animal.
Rams from tolerant flocks can be tested with a 0.6mg/kg LW dose or more, but there are still only a few flocks with such tolerance and lower doses are used initially until it’s clear the flock’s genetics can cope with a severe challenge.
Dinger warns that just because a breeder says they’re selecting for FE tolerance, it doesn’t mean to say they’ve got there. Ask what dose of sporidesmin is used, and to see the Ramguard certificate detailing the rams tested and results. When they were tested may also have a bearing, as there’s some evidence that high protein diets aid breakdown of the toxin, so spring tests will tend to produce lower GGT levels than autumn or winter ones when pasture protein content is low.
Dinger praises another retired breeder, Rex Alexander (see Country-Wide Sheep 2018) for the work he did especially with FE.
He says Marion and Rex Alexander, the late Colin Southy, a MAF advisor, and some others were the true inventors of the beginning to the FE tolerance programme which was the brainchild of Dr Neale Towers of Ruakura Research station.
“They put their money where their mouth was.”
They started The Stock Safety company and got the drenching with sporidesmin on the way.
“The FE fraternity owns Rex an enormous amount of gratitude.”
Dinger’s own flock was the first in the country to reach the 0.6 testing level, doing so in about 2001, several years before any others got there. Now there are more to choose from, of various breeds, including those operating under the FE Gold brand (see www.fegold.co.nz).
Genomic testing for tolerance is also possible, which has the advantage of being non-invasive and with no welfare implications for the tested animal, but to date it is not as reliable as the Ramguard approach.
Testing ewe hoggets has been shown to be an effective, albeit more expensive, fast-track to a tolerant flock and effective way of identifying rams that for some reason sometimes fail to pass on the tolerance a Ramguard test indicates they should do, he notes.
A complicating factor is copper: the mineral exacerbates FE so copper supplements should be avoided in FE-prone areas.
A spin-off benefit of breeding for FE tolerance is less risk of reduced ovulation due to another fungal toxin, produced by fusarium fungi in grasses and grains, zearalenone. FE-tolerant sheep also seem less prone to ryegrass staggers, a condition caused by another fungally produced toxin, lolitrem B.
Tolerance not resistance
Dinger says an animal’s ability to cope with a sporidesmin challenge, the fungal toxin that causes FE, should be referred to as tolerance, not resistance, .(see main story). His reasoning is that despite decades of testing and selection, in epidemic years when spore counts can spike above a million per gram of pasture, even tolerant stock succumb to some extent, especially lambs.
“Tolerance gives the impression of coping with a disease, whereas resistance implies the animal can’t get it anymore.”
Also, there are occasional breakdowns within tolerant flocks, thought to be caused when a ram fails to pass on the normally highly heritable trait for some reason. Research by AgResearch’s Sin Phua found at least 19 genes involved in FE tolerance and it’s possible some can be switched “on” or “off” by as-yet unknown triggers, he notes.
There are also about nine forms of sporidesmin which may have different levels of toxicity and incidence, depending on locality. Hence a ram’s tolerance may vary according to region.
It’s also possible the grain-derived sporidesmin used by Ramguard to test and select rams doesn’t match the local, pastoral fungi-produced strain. That the single-hit testing approach isn’t the best way to mimic the cumulative effect of grazing high spore count pasture for an extended time.
“Only more research will get answers to these questions,” Dinger says.
- Breeder’s insights
- Genetics most sustainable solution for most issues.
- Collaboration across breeds essential.
- Alternative protein threat should spur action.
- NZ sheep R&D spend pitiful.
- Breeders must drive change – together.