Are your ewes getting enough energy?

70% of foetal growth occurs in the last third of a ewe’s pregnancy! This means that a ewe’s requirement for energy increases rapidly in the 6 weeks prior to lambing to meet the needs of the growing lamb(s). However, the presence of lambs reduces the physical size of the rumen, making it increasingly difficult for the ewe to eat enough to satisfy her demands for energy. As a result, she can lose condition and this can lead to serious health issues.

Are your ewes getting enough energy?


Feeding Megalac in late pregnancy and early lactation is an ideal way of increasing diet energy density, helping to reduce the effect of low appetite on energy intake and assist in maintaining ewe body condition. Megalac is a rumen-protected fat, made from a combination of natural plant oil and calcium which can be fed as part of a bought-in compound or blended feed. 

Established trial work carried out by ADAS with their Rosemaund flock featured diets fed to in-lamb ewes containing Megalac as a source of supplementary energy. Pre-lambing, 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, increasing its ME to 13.9 MJ/kg DM. The concentrates were fed from 8 weeks before lambing at 0.5 kg/day, rising to 1.1 kg/day at lambing. 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. Straw was available ad-lib throughout the trial and lamb creep from 10 days to slaughter.

Ewe energy supplementation:  impact on ewe and lamb performance

Table 1: Lamb performance: ewe colostrum v Volostrum

Twin Suckling ewes

  Control  Control + energy supplement 
% ewes rearing all lambs 90 95
Lamb gain to weaning (g/day) 218 233

Table 2: Lamb performance: ewe colostrum v Volostrum

Triplet suckling ewes

  Control Control + energy supplement
% ewes rearing all lambs 60 100
Lamb gain to weaning (g/day) 170 203


The trial found that ewes which were 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. This is likely to be reflecting improved milk quality and yield in the supplemented ewes.

The trial showed that ewes carrying twins reared 95% of their lambs, 5% more than those fed the control diet. The trend was 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 the ewes fed the control diet which scored 2.0.