The quality of silage made on sheep farms has always been variable. Some highly stocked farms reliant on housing ewes for a significant period of time have the process down to a fine art, barring a weather disaster. But for many, the quality of silage, or hay for that matter, saved on farms is well below optimum.
Poor-quality silage represents a direct cost in higher volumes of concentrates required and reduced performance. The summer of 2024 was challenging in terms of saving high-quality silage, and some farmers are now weighing up how best to feed ewes transitioning from mid-to-late pregnancy.
All concentrate diets have the advantage of reducing labour and offering a consistent feed in late pregnancy.
High-concentrate diet
Concentrate costs have reduced in price over the last 12 months and this has opened up the possibility of farmers offering ewes a high- or all-concentrate diet. The last significant piece of research carried out on all concentrate diets was a paper published in 2002 by Sean Flanagan, Teagasc, titled Easy Feeding of Housed Sheep.
The trial investigated the cost of three different diets – two concentrate and one silage/concentrate diet and also looked at the labour involved in each feeding system and animal performance. The trial involved early lambing ewes which were retained indoors post-lambing.
The early lambing ewes, which were housed seven weeks pre-lambing on 17 November, had an average weight of 69kg and were allocated to three different dietary treatments as follows:
Silage ad-libitum and supplemented with pelleted concentrate;Cereal-based loose concentrate mix only and;Pelleted concentrate only.Feeding programme
The feeding programme was calculated to satisfy the energy requirements for 70kg twin-bearing ewes, which granted is lower than many ewe breeds now on farms. Baled silage was harvested from a perennial ryegrass-dominant sward and offered unchopped.
The ration comprised a 50:30:20 mix of whole barley, molassed sugar beet pulp and soybean meal, while a mineral and vitamin mix was added to deliver 20g/ewe/day.
The pelleted concentrate was a commercially available ewe and lamb nut, which going by the chemical analysis outlined in Table 2 was a high-energy feed.
A transition period of one week was provided to allow ewes to adjust to their new diets. Silage and 0.5kg concentrate or ration was offered at the outset, with silage reduced and concentrates or ration supplementation upped to 1kg per head daily.
Silage was cut from the diet of the ration/pelleted concentrate treatment, but as ewes were housed on straw bedding, this likely provided some extra roughage to the diet.
Feed was offered once daily and to ensure all ewes could access feed unrestricted a trough space allowance of 600mm/ewe was provided. Table 1 details the increase in feeding levels as ewes progressed through late pregnancy.
Care needs to be taken where ewes are bedded on straw to ensure bedding is topped up regularly to avoid ewes eating contaminated bedding.
Animal performance
It should be outlined that ewes on all three diets performed satisfactorily. The average litter size per ewe was similar across all groups at 1.84 lambs, 1.86 lambs and 1.81 lambs for the silage, loose mix and pelleted diets respectively.
The birth weight of lambs on the silage plus concentrate treatment was the lowest of the three, at an average of 4.7kg. This compared to 5.1kg for lambs born to ewes consuming pelleted concentrates and 5.3kg for lambs born to ewes in the ration/loose mix treatment.
It is worth remembering that the silage fed was not chopped, which would have slightly reduced potential intake. Recent studies carried out in Teagasc Athenry looked at the difference in performance of ewes fed chopped or unchopped silage.
These showed lambs recording a 0.2kg higher birthweight for ewes consuming precision-chop silage, with silage quality equivalent in both treatments and ewes consuming 18kg concentrates in late pregnancy. Furthermore, ewes fed very high-quality silage of 75 DMD plus gave birth to lambs weighing in excess of 5kg at birth.
The mortality figures were similar across all treatments, at 8.9% for the silage-based diet, 8.7% for pelleted concentrates and 7.9% for the ration / loose mix.
Offering ewes on all concentrate diets straw will keep ewes more content.
Dietary costs
The high quality of silage fed lowered concentrate supplementation rates to a total of just 20kg in late pregnancy, while ewes consumed 0.25t of silage over the final six-week feeding period. For the financial analysis of dietary costs outlined in Table 3, two costs of €30/t and €35/t have been taken for silage and two concentrate costs of €370/t and €400/t for this treatment.
Three costs have been used for the ration – €350/t, €370/t and €400/t, while the pelleted feed is put in at a €15/t higher cost. There are farmers purchasing feed at less than this cost and likewise there are farmers paying above €400/t, particularly where feed is purchased in 25kg bags.
Typical savings of €15/t to €25/t can be made where purchasing in bulk over bagged form.
As can be readily seen the cost of concentrates has a significant influence on total feed costs per head. Costs could possibly be lowered if the analysis looked at purchasing a cheaper feed for the initial stages of late pregnancy feeding, and switching to a higher protein feed for the final two weeks, but the savings are relatively small and especially if dealing with smaller flocks, as is dominant in Ireland and Northern Ireland.
The percentage protein content in the diet also can be lower in the all-concentrate diet, as sheep are consuming higher quantities by merit of a higher concentrate intake.
Diets should be formulated with high energy ingredients and contain a satisfactory level of protein in the final weeks of gestation.
Takeaway message
The analysis is also not planned to be absolute; it is done to give farmers a guideline of the expected performance and cost. Producers should weigh up their own figures and also aspects of the volume and quality of silage on hand.
Where sheep are housed on straw, it is important to offer a fresh source of straw, as eating soiled bedding can trigger disease which manifests in abortion. Offering straw also helps fill the rumen and keeps sheep more content. Some farmers operating such a system offer straw along the feeding passage and then use any straw not consumed for bedding.
The costs of straw would be a factor for farmers with ewes housed on slats, as it has increased significantly in recent years and as such would also represent a cost to the all-concentrate systems. Feed management with the all concentrate diets also needs to be precise to prevent digestive upsets.
The quality of silage made on sheep farms has always been variable. Some highly stocked farms reliant on housing ewes for a significant period of time have the process down to a fine art, barring a weather disaster. But for many, the quality of silage, or hay for that matter, saved on farms is well below optimum.
Poor-quality silage represents a direct cost in higher volumes of concentrates required and reduced performance. The summer of 2024 was challenging in terms of saving high-quality silage, and some farmers are now weighing up how best to feed ewes transitioning from mid-to-late pregnancy.
All concentrate diets have the advantage of reducing labour and offering a consistent feed in late pregnancy.
High-concentrate diet
Concentrate costs have reduced in price over the last 12 months and this has opened up the possibility of farmers offering ewes a high- or all-concentrate diet. The last significant piece of research carried out on all concentrate diets was a paper published in 2002 by Sean Flanagan, Teagasc, titled Easy Feeding of Housed Sheep.
The trial investigated the cost of three different diets – two concentrate and one silage/concentrate diet and also looked at the labour involved in each feeding system and animal performance. The trial involved early lambing ewes which were retained indoors post-lambing.
The early lambing ewes, which were housed seven weeks pre-lambing on 17 November, had an average weight of 69kg and were allocated to three different dietary treatments as follows:
Silage ad-libitum and supplemented with pelleted concentrate;Cereal-based loose concentrate mix only and;Pelleted concentrate only.Feeding programme
The feeding programme was calculated to satisfy the energy requirements for 70kg twin-bearing ewes, which granted is lower than many ewe breeds now on farms. Baled silage was harvested from a perennial ryegrass-dominant sward and offered unchopped.
The ration comprised a 50:30:20 mix of whole barley, molassed sugar beet pulp and soybean meal, while a mineral and vitamin mix was added to deliver 20g/ewe/day.
The pelleted concentrate was a commercially available ewe and lamb nut, which going by the chemical analysis outlined in Table 2 was a high-energy feed.
A transition period of one week was provided to allow ewes to adjust to their new diets. Silage and 0.5kg concentrate or ration was offered at the outset, with silage reduced and concentrates or ration supplementation upped to 1kg per head daily.
Silage was cut from the diet of the ration/pelleted concentrate treatment, but as ewes were housed on straw bedding, this likely provided some extra roughage to the diet.
Feed was offered once daily and to ensure all ewes could access feed unrestricted a trough space allowance of 600mm/ewe was provided. Table 1 details the increase in feeding levels as ewes progressed through late pregnancy.
Care needs to be taken where ewes are bedded on straw to ensure bedding is topped up regularly to avoid ewes eating contaminated bedding.
Animal performance
It should be outlined that ewes on all three diets performed satisfactorily. The average litter size per ewe was similar across all groups at 1.84 lambs, 1.86 lambs and 1.81 lambs for the silage, loose mix and pelleted diets respectively.
The birth weight of lambs on the silage plus concentrate treatment was the lowest of the three, at an average of 4.7kg. This compared to 5.1kg for lambs born to ewes consuming pelleted concentrates and 5.3kg for lambs born to ewes in the ration/loose mix treatment.
It is worth remembering that the silage fed was not chopped, which would have slightly reduced potential intake. Recent studies carried out in Teagasc Athenry looked at the difference in performance of ewes fed chopped or unchopped silage.
These showed lambs recording a 0.2kg higher birthweight for ewes consuming precision-chop silage, with silage quality equivalent in both treatments and ewes consuming 18kg concentrates in late pregnancy. Furthermore, ewes fed very high-quality silage of 75 DMD plus gave birth to lambs weighing in excess of 5kg at birth.
The mortality figures were similar across all treatments, at 8.9% for the silage-based diet, 8.7% for pelleted concentrates and 7.9% for the ration / loose mix.
Offering ewes on all concentrate diets straw will keep ewes more content.
Dietary costs
The high quality of silage fed lowered concentrate supplementation rates to a total of just 20kg in late pregnancy, while ewes consumed 0.25t of silage over the final six-week feeding period. For the financial analysis of dietary costs outlined in Table 3, two costs of €30/t and €35/t have been taken for silage and two concentrate costs of €370/t and €400/t for this treatment.
Three costs have been used for the ration – €350/t, €370/t and €400/t, while the pelleted feed is put in at a €15/t higher cost. There are farmers purchasing feed at less than this cost and likewise there are farmers paying above €400/t, particularly where feed is purchased in 25kg bags.
Typical savings of €15/t to €25/t can be made where purchasing in bulk over bagged form.
As can be readily seen the cost of concentrates has a significant influence on total feed costs per head. Costs could possibly be lowered if the analysis looked at purchasing a cheaper feed for the initial stages of late pregnancy feeding, and switching to a higher protein feed for the final two weeks, but the savings are relatively small and especially if dealing with smaller flocks, as is dominant in Ireland and Northern Ireland.
The percentage protein content in the diet also can be lower in the all-concentrate diet, as sheep are consuming higher quantities by merit of a higher concentrate intake.
Diets should be formulated with high energy ingredients and contain a satisfactory level of protein in the final weeks of gestation.
Takeaway message
The analysis is also not planned to be absolute; it is done to give farmers a guideline of the expected performance and cost. Producers should weigh up their own figures and also aspects of the volume and quality of silage on hand.
Where sheep are housed on straw, it is important to offer a fresh source of straw, as eating soiled bedding can trigger disease which manifests in abortion. Offering straw also helps fill the rumen and keeps sheep more content. Some farmers operating such a system offer straw along the feeding passage and then use any straw not consumed for bedding.
The costs of straw would be a factor for farmers with ewes housed on slats, as it has increased significantly in recent years and as such would also represent a cost to the all-concentrate systems. Feed management with the all concentrate diets also needs to be precise to prevent digestive upsets.
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