Organic farmer, Matt Ridley, has finished his lambs without concentrates for the past seven years. He explains how high quality silage, preserved with organic-approved Activator + CA, is the basis of this process.
Finishing lambs without a single grain of concentrate feed is impressive by any standards, but doing so under an organic system demands even more care with sheep forages and breeds. All going to plan, Northumberland farmer, Matt Ridley will achieve this for his 2020 lamb crop, just as he has done for the past seven years.
Mr Ridley keeps 2,000 ewes in his hefted flock at the top of the Coquet Valley in the Cheviot Hills. But it is his 1,000 head lowland flock, kept on the home farm at Aydon North, Corbridge in the Tyne Valley, which is produced to organic standards.
Growing as much feed as possible on the farm is a key priority, and he says: “As anyone who has tried to buy organic protein knows, the price is horrendous.”
To this end, he concentrates on growing swards containing high protein red or white clover, producing silage with minimal waste while maximising nutrient retention, and introducing sheep breeds which are proven to do well on forage and grass.
Almost all lambs hit the target grade of U3L or E3L, and the average carcase weight is 20kg.
Lambing starts this year, as it did in 2019, from 20 March and runs for just one month. The earliest single lambs are drawn off for sale in July and a gradual flow of twins and triplets is usually sold through to mid-December.
The first focus to meeting these targets is maintaining the condition of ewes, considered essential in giving the lambs the best possible start.
“Sheep in good condition can cope better with whatever situation they face, including the weather,” says Mr Ridley. “We certainly don’t want lean sheep in late pregnancy as you can’t put weight on them after that when they’re putting everything into their lambs.”
He has therefore fine-tuned his system, moving ewes from grazed grass and on to high quality silage through the winter months, as conditions dictate.
“The ewes will be out on silage from tupping, depending on the weather and the amount of grass,” he says. “This winter we switched to silage later – in around mid-December – because we had plenty of autumn grazing.”
The key to maintaining their condition during pregnancy is said to be presenting them with quality, palatable silage which the ewes will eat in quantity and with ease.
“We used to treat silage as belly-fill and made it from old pastures and into big bales,” he says. “But the sheep didn’t use it efficiently, rushing for it when it was brought out, spending a lot of time clambering on top of the bales to pull out the silage, and probably using lots of energy in the process.”
Since then he has switched to short-chopped clamp silage but has spent several years searching for the most effective method of preservation which conforms to organic standards.
“I really wanted to use the salts-based preservative, Safesil, as we know it gives the most stable fermentation but we were unable to use this under an organic system,” he says. “So, we continued to try several bacterial inoculants which are organic-approved, but unfortunately, they’ve tended to give us disappointing results.
“The silage would often heat up and some had mould at the surface and there was usually some rejection by the stock,” he says.
Having exhausted many options, Kelvin Cave Ltd suggested he tried Activator + CA, an inoculant containing a specific strain of Lactobacillus plantarum in combination with a specific, organically certified, citrate which produces powerful yeast and mould inhibitors and improves the aerobic stability of silage (see panel).
Feeding pregnant ewes high quality silage is key to lamb growth.
Activator + CA: How it Works
Activator + CA comprises the same elite strain of Lactobacillus plantarum used in Activator Plus, with the addition of a specific citrate which provides an additional food source for the bacteria, leading to the production of powerful yeast-inhibiting compounds. This makes Activator + CA ideal for use on higher DM grass silages (28%DM+), wholecrop cereal and arable silages, maize silage and crimped cereals, all of which can be prone to aerobic spoilage by yeasts, which are present on the crop at harvest.
As they grow, the yeasts consume lactic acid and sugars, causing significant loss of nutrient value and raising the silage pH to a point at which moulds can grow. These cause further losses and increase the risk of raised mycotoxin levels which can hit animal health, performance and fertility.
Activator + CA has been independently demonstrated to give substantially better aerobic stability than Activator Plus. The product is organic-approved.
Michael Carpenter, the company’s northern manager explains his recommendation, remarking that L plantarum is a homofermentative bacterium.
“As a homofermenter, L plantarum converts sugar to lactic acid, which is the strongest fermentation acid. This results in a rapid drop in the silage pH which has been proven to ensure maximum retention of true protein and energy,” he says. “It’s important to note that this is in contrast to heterofermentative inoculants which ferment sugars in a far more inefficient way, producing water and carbon dioxide as by-products – a process we’ve completely avoided with this new fermentation pathway.”
The result, according to Mr Ridley is a stable, palatable product which keeps fresh for days and produces high dry matter intakes.
“We feed it to the ewes in trailers every three days and it stays completely cold and fresh during that time,” he says.
Anything left after that is fed to the farm’s cattle when it still remains palatable and cold.
Because of its long-lasting qualities it is effectively available to the ewes ad lib which has led to a noticeable increase in dry matter intakes, less of a rush for the food and a more contented flock.
“By the end of gestation the ewes are in good condition, and receive just a small amount of home-grown concentrates for the final four weeks,” he says. “We find if they are in good condition in late pregnancy the lambs get off to a good start and never look back.”
At the earliest opportunity, lambs are moved for rearing and finishing on to high quality swards, all of which include either red or white clover.
“We grow the best grass varieties we can and reseed every 5-7 years,” he says. “But there’s a limit to how much red clover we can grow as we can’t tup ewes on red clover because of its negative effects on fertility.”
Red clover is often undersown with an arable silage, such as a barley, oat and pea mix. This will usually be whole-cropped in August and
the undersown clover used for autumn grazing the lambs.
“We’ll only graze it lightly in autumn, just to encourage tillering,” he says. “We’ll return to it the following spring, and possibly again the next autumn.”
With only one cut of silage taken in June, there is plenty of grazing for fattening the lambs.
Equal attention has been given to the replacement breeding programme, with the same aim of maximising performance from forage and grass.
For the past four years, this has involved the use of Aberfield rams on the Texel x Lleyn lowland flock.
“These rams have been bred to perform on grass and would have been removed from the breeding programme if they didn’t do so,” he says. “I buy them as shearlings and when they arrive, it’s clear they have never seen a bag of feed.
“We use one ram per 30-40 ewes despite their mating capacity of 80-100, as it’s important for us to lamb in a tight block.”
Selecting his rams on Estimated Breeding Values (EBVs), he says he has focused selection on maternal traits.
“We want a reasonable but not excessive lambing percentage, good maternal ability and a relatively lightweight ewe, as the larger animals require more feed for maintenance,” he says.
While building up his closed flock of breeding ewes to include the Aberfield bloodlines – also using the Aberfield SR which includes some Lleyn blood – he continues to use a Texel ram as a purely terminal sire.
Lambing percentage was 190% for the March 2019 crop, which was recorded through a benchmarking service against other organic flocks with the University of Newcastle.
“This year we hope for a similar lambing percentage,” he says. “We don’t want to scan at more than 200% as this means we’ll have too many triplets.”
With the start of lambing now upon us, he is implementing a few changes he hopes will further improve performance, including a lower stocking rate when the ewes lamb outdoors.
“We normally lead the lambs in to spray navels and ring tails and once they have sucked we turn them back out,” he says. “But this year we are trying a simpler method and hope that keeping them on a larger area will reduce mis-mothering as well as infectious disease such as watery mouth and joint ill.
“All going to plan, this will be less labour intensive, and if the weather permits, we won’t bring them in for lambing at all.”