Sheep: Improving lamb productivity through supplementation

SUPPLEMENTING the diets of pregnant ewes with biotin can have a big impact on lamb productivity, with a new trial reporting higher lamb birth weights and increased liveweight gain.

ADAS livestock consultant Kate Phillips says: “Biotin, a water soluble B-vitamin is widely known for its role in hoof horn formation.

“It also has a significant effect on the rumen fermentation of carbohydrate into propionic acid and subsequently into glucose. By improving energy metabolism it can boost animal performance and a farm trial feeding extra biotin to ewes showed a significant economic benefit.”

Welsh Mules

Andrew and Emma Baldwyn run a flock of 920 breeding ewes and 260 ewe lambs at Lower Berrow Farm, near Redditch. The ewes are predominantly Welsh Mules with some Suffolk crosses and around 1,800 lambs are sold annually with others retained as replacements. Texel and Suffolk rams go in with the first batch of ewes in late August with further batches tupped during October. The final group will include the ewe lambs.

Ewes are house around five weeks pre-lambing depending on the weather and fed a TMR ration based on grass silage, fodder beet, barley and soya. Ewes and lambs are usually turned out within 24 hours of lambing and lambs are creep fed from one week old and remain on the ewes until sold at 40kg, at around 12-16 weeks old. Most lambs are sold deadweight through the Cotswold Sheep Group although the last 200 are usually sold as stores.

Trial groups

The trial compared two groups of 200 twin-bearing ewes, one group fed 5mg per day of biotin included in the minerals and the other group did not receive biotin. Otherwise the diets were identical. The additional biotin was fed for six weeks pre- and two weeks post-lambing and Ms Phillips says is essential the correct supplementary rate is used for the full pre- and post-lambing period.

Lambs were weighted at birth and again at four to six weeks and 10 to 12 weeks old to assess growth rate with more than 540 lambs included in the trial.

“The lambs born from biotin supplemented ewes were 8 per cent heavier at birth at 5.14kg compared to 4.76kg,” Ms Phillips says.

“Initially the daily liveweight gain was similar for both supplemented and unsupplemented lambs at 330g/day. However, during the later part of the 10-week trial the growth rate of lambs from the supplemented ewes was significantly higher at 401g/day compared to 363g/day, an increase of 11 per cent.

“Overall the lambs from supplemented ewes were 1.5kg heavier at 10 weeks old. If valued at £2/kg this equates to a £3 benefit per lamb, giving a 6:1 return on the 50p investment in additional biotin. Alternatively lambs would reach the 40kg target weight a week earlier,” says Ms Phillips.

Finishing

Andrew Baldwyn says the first he knew the biotin lambs were finishing quicker was when he saw a reduction in the number with the distinctive ear tags. “It was hard to spot the extra growth and there was no difference in vigour, but when we weighed lambs we thought were close to 40kg we noticed the biotin supplemented lambs were finishing quicker because there were fewer lambs with the ear tags identifying the trial lambs.

“On average they were sold a week earlier which has a big cashflow benefit especially as we want to move lambs on when the prices are strongest. Also selling younger means we are saving on creep which must be a good thing.”

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