Commercial plains sheep are very large, which increases maintenance costs and hinders profitability.
That’s according to Tim Byrne of Abacus Bio, a science and technology consulting firm that conducts modeled research that estimates farmed female adult weight.
See also: Test sheep data leads to bigger lamb check
Speaking to producers from across Europe at the Sheep Breeders’ Round Table (Derby, November 11-13), Dr Byrne said ewes weighing an average of 55kg were optimal and the most profitable ewes could weigh 55-65kg.
The model takes into account all costs, including the effect of changes in maintenance prices, lamb inspection and the price of ewes at slaughter per 100 sheep.
Control maintenance costs
Perthshire-based farm consultant Emily Grant of Forrit Consultancy said 400 85kg sheep would have the same dry matter (DM) intake as 500 67kg sheep.
“Farms have shown that they can increase productivity by managing small ewes,” Ms Grant said. “The challenge is that extra lambs increase the demand for grass because they also have DM intake.”
He suggested that a 55kg sheep might be too light, given that getting to slaughter weight quickly (typically 42kg) is essential to an economical system.
He added: “Ideally your system will sell all the lambs before tupping, so the ewes can overwinter on grass and you can graze for good combing rather than forage for good combing.”
Combining rotational grazing with average sheep size produced “huge gains” in increased pasture production from the same area.
“The biggest gain is from shortening [grazing periods] from four to seven days to one to two days and to increase the resting period of grazed grasses.
How to review your sheep breed
- See kg yield/year: This is often a key indicator of profitability, but you should ask yourself if this is supported by expensive inputs such as fertilizer or concentrate feed.
- Does high production bring you margins? A sheep may be very fertile for four months, but what is the value of eight unproductive months?
- What is optimal scanning? Scanning at 190-200% often means too many triplets, and triplets have higher mortality after additional feed costs. Indoors, a scan of 180-185% may be optimal, while outdoors, a scan of 170-175% may be best.
Larger sheep are suitable for some systems
Derek Hall breeds Lilyburn, Penicuik, Mules and Blue-faced Leicesters, which he says sell well for the size and milkiness of the resulting Mule ewes.
Mr Hall admits priorities vary between systems and parts of the country, but for many the “holy grail” was a sheep producing two 20kg carcasses in 12 weeks.
“We’ve seen the benefit of having bigger lambs this year,” he said. “The extra 4kg was worth £15 and not worth the extra kilos just because there weren’t heavy lambs.”
He noted the following points:
- The study was based on a model – real farm experience may differ in practice
- Previous work by the Meat and Livestock Commission has shown that the weight at which a lamb will reach R3L is half the average mature weight of its parents.
- If 75kg ewes were kept at 10 ewes/ha, 180% scanned and 170% reared in an indoor and outdoor lambing system and a 45kg lamb was obtained, this would be 17x45kg = 765kg liveweight/ha.
- The 63kg ewe had to scan, ejaculate and milk very well to match this performance
- Cut-off days for methane emissions were key.
A grass-based switch reduces sheep by 10 kg
Changing pasture productivity on a Warwickshire farm reduced the weight of mature ewes in a leading Suffolk flock by 10-15kg.
Since 2010, the Harding family at Lodge Farm, near Nuneaton, have switched from a creep-fed, early lambing system to one based on the animal’s ability to maintain body condition and produce lambs from grass.
This reduced the weight of adult sheep from 110 kg to 90-95 kg.
Rams are now sold off the farm without any creep. The herd sold 242 rams this year, nearly 100 more than two years ago.
Feeding the rams with concentrate meant that although the rams produced high performance and well-bred lambs, they were not long enough for customers.
Buyers producing Suffolk Mules have had great experience with the new commercially bred tups.
They feared that the lighter and smaller gun would not suit some buyers.
Adjusting sheep size increases profits
Matt Harding, who runs the farm with his parents Charles and Jan and wife Ellie and spoke at this year’s Sheep Breeders’ Roundtable, believes that adjusting sheep size increases profits and increases yield/ha for home and customers.
“Mature ewes are smaller in size and I think we’ve selected for ewes that maintain condition in a grass-based system, so the amount of feed eaten to meet maintenance requirements is less in younger ewes,” Mr Harding said. Farmers Week.
Farm facts: Lodge Farm
- 180 Suffolks (92-95 kg)
- 170 Aberblacks (80-85 kg)
- 120 Aberfield (70kg)
- 72.8 ha (180 hectares) is owned
- 20 ha (50 acres) for rent
- 100 ha (247 hectares) of arable cover crops were grazed from December to the end of March
- Lowland grassland on loamy and loamy soil
He added: “I’ve probably managed 120 Aberfields and their lambs at 70kg mature weight this year compared to 100 Suffolks and their lambs at 91kg. Therefore, there is a 20% increase in cattle collection.”
Mr Harding says that during the harsh dry summer the sheep had to be kept in the sacrificial fields and fed on silage until the rains came and the grasses recovered. All sheep are lighter this year.
“It wouldn’t have happened a few years ago without concentrate feed, we can get them back on track quickly when they have quality grass in front of them.”
What has changed
- Later lambing: Ewe DM intake was adjusted to farm DM production and lambing was delayed by two months from January to March.
- Selling a shovel, not a lamb: Instead of 90 kg ram lambs, he started selling 100-110 kg grass-fed furs. This has increased the demand for socks in winter, so they are rotated on cover crops around a nearby crop farm. Previously, tups lasted two to four years with clients; it now averages over five years.
- Growing from grass: Suffolk ewes are placed for lambing, but in the shortest possible time their lambs are out on the grass where they have rested during the winter. They are grazed in rotation on 2 ha (5 acre) pastures with no concentrate given to sheep or lambs. Lambs are growing at 380g per day to eight weeks, which is 10g higher than the last year of creep feeding 10 years ago.
- Cut by condition: Many ewes “were out” of the grass-based system, but some were able to manage. Sheep that cannot maintain their condition are always slaughtered.
- Grass based genetics: Sandyknowe genetics were purchased from grass-based Suffolk breeder Malcolm Stewart, Earlston. Sandyknowe Sole Trade went to the herd and Bentley Retallick, who is 50% New Zealand blood, also made a significant impact. Recently, Sandyknowe Trent has had a major impact on estimated breeding values and growth rates. His progeny has the best growth rate seen on the farm to date.