Tranquility prevails on many sheep farms but this is the calm before the storm.
Nutritional management during late pregnancy affects colostrum quality and quantity, ease of lambing, lamb survival, lamb birth weight and formation of the ewe-lamb bond.
All of these factors affect lamb performance from birth to sale, flock productivity and labour requirement during the lambing period – the key factors influencing flock profitability and job satisfaction.
Silage feed value
The main factor influencing silage feed value is digestibility (DMD).
The effects of silage DMD on food intake in a recent study are presented in Figure 1.
Increasing DMD increased silage intake during weeks -10 to -6 prior to lambing.
When concentrate supplementation was initiated (week -6) the intake of medium DMD silage remained relatively unchanged up to lambing while that of the high DMD silage declined as concentrate feed level increased.
Concentrate displaced the high DMD silage in the diet. Increasing silage DMD increased ME intake by 53% during the final six weeks of pregnancy.
The effects of silage DMD on ewe performance is presented in Table 1.
The ewes offered the high DMD silage were 10kg heavier and had a higher body condition score (BCS) at lambing.
At pasture, between lambing and weaning the ewes that had been offered the high DMD silage lost 0.5 units BCS (sacrificed body reserves in favour of milk production) while those offered the medium DMD silage gained 0.2 units BCS (partitioned energy intake to replenish their own body reserves rather than to milk production).
The effects of the DMD of silage offered to ewes while housed on the performance of their lambs at pasture are presented in Table 2.
The lambs from ewes offered the high DMD silage were: 0.5kg heavier at birth, 1.9kg heavier at weaning and 17 days younger at slaughter.
A reduction of 17 days at slaughter is equivalent to the response expected from feeding 19kg concentrate per lamb from birth to slaughter.
As each ewe in the study reared 1.75 lambs, this would equate to 33kg concentrate/ewe – equivalent to approximately €14/ewe.
Concentrate supplementation
While increasing concentrate intake to ewes offered the medium DMD silage yielded a small improvement in BCS at lambing (Table 1) it had no impact on lamb performance (Table 2). Thus, feeding excess concentrate in late pregnancy does not improve lamb performance and will result in a negative return on concentrate expenditure.
The effects of silage feed value on the concentrate requirement of twin-bearing ewes in late pregnancy are shown in Table 3.
It is assumed that ewes have access to fresh silage 24 hours daily.
Concentrate requirement is influenced primarily by silage DMD (but also by chop length). The concentrate requirements per ewe can be reduced by 5kg for single-bearing ewes, and increased by 8kg for ewes carrying triplets.
An Athenry study evaluated two concentrates which were formulated to have the same ME and crude protein concentrations and used either soya bean meal or a mixture of byproducts (rapeseed, maize distillers and maize gluten) as the main protein source.
The concentrates were offered to ewes during late pregnancy. Lambs born to ewes that were offered the soyabean-based concentrate were 0.3kg and 0.9kg heavier at birth and weaning, respectively, than lambs born to ewes offered the concentrate containing byproducts as the protein source. The increase in weaning weight of 0.9kg (extra cost ~€0.60/ewe) is similar to the response obtained from offering each lamb 6kg of creep concentrate until weaning (cost ~ €5/ewe per set of twins).
Lambs from ewes that were offered 16kg of the soya-based concentrate were the same weight at weaning as lambs from ewes offered 28kg of the concentrate containing the byproducts.
The ingredient composition of the concentrate that I have formulated (19% protein) for ewes during late pregnancy at Athenry this year is presented in Table 4. When purchasing concentrates base your decisions on ingredient composition rather than solely on price.
A reduction in concentrate price of €20/t equates to a saving equivalent to only €0.50/ewe.
To optimise the use of concentrate, ewes should be grouped according to predicted litter size (based on ultrasonic scanning) and expected lambing date.
Analyse your silage and base supplementation levels on data presented in Table 3.
Supplementation should be stepped up weekly over the weeks immediately prior to lambing to coincide with ewe requirements.
Each five percentage point increase in silage DMD increases ewe weight post lambing by 6.5kg and lamb birth weight by 0.25kg. Construct a plan with the aim of increasing next year’s silage DMD by at least 5% units.Develop a late pregnancy nutrition plan. Purchase concentrate on ingredient composition and not solely on price.Excess concentrate supplementation is unlikely to yield an economic response. Implementation of an effective nutrition plan during this “time of tranquility” in the sheep shed will reduce stress for both ewe and farmer during the hectic lambing period.
Tranquility prevails on many sheep farms but this is the calm before the storm.
Nutritional management during late pregnancy affects colostrum quality and quantity, ease of lambing, lamb survival, lamb birth weight and formation of the ewe-lamb bond.
All of these factors affect lamb performance from birth to sale, flock productivity and labour requirement during the lambing period – the key factors influencing flock profitability and job satisfaction.
Silage feed value
The main factor influencing silage feed value is digestibility (DMD).
The effects of silage DMD on food intake in a recent study are presented in Figure 1.
Increasing DMD increased silage intake during weeks -10 to -6 prior to lambing.
When concentrate supplementation was initiated (week -6) the intake of medium DMD silage remained relatively unchanged up to lambing while that of the high DMD silage declined as concentrate feed level increased.
Concentrate displaced the high DMD silage in the diet. Increasing silage DMD increased ME intake by 53% during the final six weeks of pregnancy.
The effects of silage DMD on ewe performance is presented in Table 1.
The ewes offered the high DMD silage were 10kg heavier and had a higher body condition score (BCS) at lambing.
At pasture, between lambing and weaning the ewes that had been offered the high DMD silage lost 0.5 units BCS (sacrificed body reserves in favour of milk production) while those offered the medium DMD silage gained 0.2 units BCS (partitioned energy intake to replenish their own body reserves rather than to milk production).
The effects of the DMD of silage offered to ewes while housed on the performance of their lambs at pasture are presented in Table 2.
The lambs from ewes offered the high DMD silage were: 0.5kg heavier at birth, 1.9kg heavier at weaning and 17 days younger at slaughter.
A reduction of 17 days at slaughter is equivalent to the response expected from feeding 19kg concentrate per lamb from birth to slaughter.
As each ewe in the study reared 1.75 lambs, this would equate to 33kg concentrate/ewe – equivalent to approximately €14/ewe.
Concentrate supplementation
While increasing concentrate intake to ewes offered the medium DMD silage yielded a small improvement in BCS at lambing (Table 1) it had no impact on lamb performance (Table 2). Thus, feeding excess concentrate in late pregnancy does not improve lamb performance and will result in a negative return on concentrate expenditure.
The effects of silage feed value on the concentrate requirement of twin-bearing ewes in late pregnancy are shown in Table 3.
It is assumed that ewes have access to fresh silage 24 hours daily.
Concentrate requirement is influenced primarily by silage DMD (but also by chop length). The concentrate requirements per ewe can be reduced by 5kg for single-bearing ewes, and increased by 8kg for ewes carrying triplets.
An Athenry study evaluated two concentrates which were formulated to have the same ME and crude protein concentrations and used either soya bean meal or a mixture of byproducts (rapeseed, maize distillers and maize gluten) as the main protein source.
The concentrates were offered to ewes during late pregnancy. Lambs born to ewes that were offered the soyabean-based concentrate were 0.3kg and 0.9kg heavier at birth and weaning, respectively, than lambs born to ewes offered the concentrate containing byproducts as the protein source. The increase in weaning weight of 0.9kg (extra cost ~€0.60/ewe) is similar to the response obtained from offering each lamb 6kg of creep concentrate until weaning (cost ~ €5/ewe per set of twins).
Lambs from ewes that were offered 16kg of the soya-based concentrate were the same weight at weaning as lambs from ewes offered 28kg of the concentrate containing the byproducts.
The ingredient composition of the concentrate that I have formulated (19% protein) for ewes during late pregnancy at Athenry this year is presented in Table 4. When purchasing concentrates base your decisions on ingredient composition rather than solely on price.
A reduction in concentrate price of €20/t equates to a saving equivalent to only €0.50/ewe.
To optimise the use of concentrate, ewes should be grouped according to predicted litter size (based on ultrasonic scanning) and expected lambing date.
Analyse your silage and base supplementation levels on data presented in Table 3.
Supplementation should be stepped up weekly over the weeks immediately prior to lambing to coincide with ewe requirements.
Each five percentage point increase in silage DMD increases ewe weight post lambing by 6.5kg and lamb birth weight by 0.25kg. Construct a plan with the aim of increasing next year’s silage DMD by at least 5% units.Develop a late pregnancy nutrition plan. Purchase concentrate on ingredient composition and not solely on price.Excess concentrate supplementation is unlikely to yield an economic response. Implementation of an effective nutrition plan during this “time of tranquility” in the sheep shed will reduce stress for both ewe and farmer during the hectic lambing period. 
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