DCSIMG

Energy-rich diets help boost lamb numbers

Ewes fed higher energy concentrate rear significantly more and faster growing lambs, Jeannie Everington, Volac International.

Ewes fed higher energy concentrate rear significantly more and faster growing lambs, Jeannie Everington, Volac International.

WILL our in-lamb ewes get enough energy from poor quality winter forage is the key question being asked by many farmers.

A question that needs a positive response, particularly during the final six weeks of pregnancy, says Jeannie Everington of Volac.

“Around 70% of foetal growth is in the last third of pregnancy so a ewe’s requirement for energy increases rapidly in the six weeks before lambing to meet the needs of her growing lambs,” Jeannie noted.

“However, the presence of lambs reduces the physical size of the rumen making it increasingly difficult for the ewe to eat sufficient to satisfy demands for energy to ensure a trouble free lambing as well as produce enough high quality colostrum and milk to get lambs off to the best possible start. Consequently the ewe can lose condition rapidly leading to serious health issues, including twin lamb disease.

“To minimise these pre-lambing risks feeding a high energy supplement to ewes carrying multiple lambs and/or with poor body condition score will help bridge the natural energy deficit in late pregnancy and early lactation. Ewes should be neither too thin nor too fat.”

Trials by ADAS on their Rosemaund flock featured diets fed to in-lamb ewes during late pregnancy and early lactation containing rumen protected fat as a source of supplementary energy.

100 ewes were fed either a control concentrate - ME 12.7 MJ/kg DM, or a treatment concentrate in which 10% of the cereal ingredients were replaced with Megalac, a rumen protected fat, which increased its ME to 13.9 MJ/kg DM. The concentrates were fed from eight weeks before lambing starting at 0.5 kg/day, rising to 1.1 kg/day.

Post lambing, ewes were fed 1.4 kg concentrates per day, with ME concentrations of 12.5 and 14.0 MJ/kg DM for the control and Megalac-supplemented concentrates, respectively. Ad lib straw was available throughout the trial.

“Ewes offered the higher energy concentrate reared significantly more lambs, with lamb growth rate up to 19.4% higher to weaning compared to the control group,” Jeannie Everington added.

See table 1.

“The trial showed that ewes carrying twins reared 95% of their lambs, 5% more than those fed the control diet. Furthermore, the trend was much more apparent in the triplet group where all the ewes reared 100% of their lambs, compared with only 60% of lambs successfully reared by those fed the control diet.

“In addition, the ewes fed Megalac were in better body condition at weaning, scoring an average 2.4 compared with 2.0 for the ewes fed the control diet.”

“Feeding rumen protected fat in late pregnancy and early lactation will increase diet energy density and can be fed by top-dressing or as part of a bought-in compound or blended feed.”

WALES

Welsh farmer Martin Watkins has discovered the benefits of feeding an energy dense diet, featuring rumen protected fat, both pre and post lambing to a 3,000 ewe flock run in partnership with his brother-in-law Edward Harris near Knighton in Powys.

“Since we’ve introduced a 13MJ/kg compound fed to all ewes four to six weeks prior to lambing, we’ve seen an obvious improvement in performance and now continue feeding the same supplement through to May,” he explained.

“The ewes have a great deal more energy to rear their lambs, they’re milkier and the lambs have greater get up and go. So much so, we’re achieving more lambs reared; both our Suffolk and Mule ewes rearing percentage has increased from 150% to 175% and our Welsh ewes, from 120% to 135%.

“Added together and we’re now rearing approximately 550 additional lambs off the unit, of which approximately three quarters are finished and the remainder are for replacements. That is a very significant figure and it is accompanied by real cost benefits.”

 
 
 

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