Having a flock of ewes that are in good body condition should be viewed as a resource that is important to protect. The reasoning behind this statement is straightforward. It takes a significant feed resource to bring about an improvement in ewe condition. The cost of this feed resource is significant at all stages of the year, but it is particularly expensive during the winter months.
For example, it takes a lowland ewe anywhere from eight to 12 weeks to gain one condition score (10kg to 12kg liveweight) on good-quality grass. This is the most economical route of gaining condition, with the cost much higher where supplementary feeding is the route for this gain.
For this reason, it is important to protect ewe condition now and over the next couple of months to be in a position to exploit it in late pregnancy and early lactation when it will deliver the greatest benefit in both underpinning performance and reducing costs.
The quality of silage on offer will have a profound effect on animal performance and also have a direct influence on winter feed costs.
Stage of gestation
The nutritional requirements of ewes will differ significantly depending on the stage of gestation. For ewes in early pregnancy, it is vital that they are maintained on a high plane of nutrition to promote embryo attachment to the wall of the uterus and prevent early embryo loss. This is important for the first four weeks of gestation.
After this, feeding can be targeted at maintenance levels or slightly below maintenance levels for a period. Research has shown that a small level of weight loss in mid-pregnancy can have a positive influence on placental development and, in turn, ensure optimum delivery of nutrients to the developing foetus(es). The critical words in this sentence are a “small level of weight loss” and this should be limited to a maximum of 5% of bodyweight.
It should also only take place where ewes are in a body condition score which facilitates it to occur. Lowland ewes should enter late pregnancy in a body condition score of at least 3 and preferably higher, while hill ewes should ideally have a condition score of at least 2.7.
For many mid-season lambing flocks, feeding a maintenance diet should now be the focus. The size and weight of ewes will influence the maintenance feed levels, with a 70kg ewe in mid-pregnancy requiring 0.8UFL to satisfy maintenance demands. This can be adjusted accordingly for heavier or lighter ewes.
Early lambing ewes entering late pregnancy will require a rising plane of nutrition in the final six to eight weeks of pregnancy to satisfy a sharp increase in ewe energy requirements. \ David Ruffles
Feed quality
Despite utilisation suffering in recent weeks, grass reserves are still in good shape on medium and lowly stocked farms and access to moderate-quality grass such as cleaning off paddocks or deferred grazing will meet maintenance demands. Highly stocked farms have a lower grass reserve built up but should still be in a position to sustain ewes outdoors until early to mid-December or possibly later, depending on grass utilisation.
If ewes remain outdoors until well into the new year on deferred grazing, they will generally need access to between 1.5kg and 1.7kg grass dry matter to deliver in the region of 1.15kg to 1.3kg grass DM at 75% utilisation.
Table 1 details the feed value of silage and hay at varying levels of dry matter digestibility. The difference in feeding value should serve to highlight the importance of getting silage tested well in advance of when it will be required, so that an accurate feeding programme can be put in place. Many merchants will facilitate silage testing, as will advisers and consultants.
Access to moderate- to good-quality silage of 67DMD to 70DMD will be fine for ewes in good body condition during mid-pregnancy. As long as protein levels are also reasonable (11% to 12%), then no supplementation apart from the exception of mineral/vitamins, if required, is necessary.
Silage intake
Ewes will need to consume about 1.1kg to 1.2kg silage dry matter, equivalent to 5kg silage freshweight at 20% dry matter or 3.5kg to 4kg freshweight at 25% to 30% dry matter. Poor-quality low-digestibility silage will depress intake in ewes and leave them unable to physically consume enough silage to satisfy nutritional demands.
For example, if silage is below 60 DMD, has been ensiled wet and, as a result, preserved poorly, ewes will at best only be capable of consuming 0.6kg to 0.7kg DM. Combined with the poorer feed value, ewes offered such silage will only be receiving 50% to 60% of their daily nutritional requirements. The long-term consequences of such a scenario are serious, with weight loss of up to 1kg or higher per week. As already mentioned, identifying issues like this well in advance of supplementary feeding being required will allow alternate plans to be put in place.
The manner in which silage has been saved will also have an effect on ewe intake potential as demonstrated in Table 2.
Ewes fed precision-chop silage will be able to consume higher volumes which, in turn, will reduce the volume of concentrate supplementation required in late pregnancy.
Hay typically has a lower energy value but where it is good-quality, ewes can compensate somewhat by consuming higher volumes. Some reports suggest silage is testing below anticipated, with silage made late in the year preserving poorly in cases or having a low dry matter content. This raises the importance of accurately identifying the quality of silage on hand.
Late pregnancy feeding
The body condition score of ewes continues to hold major significance in late pregnancy. Research shows that a 0.5 unit reduction in BCS in the final month of pregnancy can impair lamb survivability to the tune of 5%. The research also highlights the downside of ewes entering late pregnancy in poor body condition, with each drop of 0.5 in condition score below BCS 3 at lambing reducing lamb survivability by 5%.
This is not to forget the negative consequences on lamb birth weights and vigour and the quality and quantity of colostrum produced. Early lambing flocks starting to lamb from the end of December are entering the critical final six- to eight-week period. During this time, energy requirements for a twin-bearing lowland ewe follow a sharp upward curve, rising from 12.2MJ ME/kg DM to 20.2 MJ ME/kg DM, while the protein requirement also jumps to 137g of metabolisable protein in the final week of pregnancy.
High-energy diet
The universal concentrate supplementation guide based on varying silage quality is detailed in Table 3. Where dealing with very poor-quality silage, this should only act as a roughage source in late pregnancy. It is also unsuitable for an early lambing production system where ewes and lambs are likely to be maintained indoors for a significant period post-lambing. If this is the case, then an alternative source of forage should be sourced in the coming weeks.
It should also be noted that the feeding programme in Table 3 can be used as a blueprint for farmers participating in the Sheep Welfare Scheme who selected the optional measure of ultrasound pregnancy scanning.
When selecting concentrates for feeding ewes or finishing lambs, it is important to ensure that it is formulated with high-energy ingredients. Table 4 is a useful guide to the energy and protein content of regularly used ingredients.
Feeds must list their ingredients in order of inclusion levels. The high-feed-value cereal ingredients should form the foundation of the feed and alarm bells should ring where ingredients with a low-energy rating are located towards the top of the ingredient inclusion listing.
In terms of protein, the general recommendation is a concentrate content of 18% to 20% for medium litter sizes (1.6 to 1.9 lambs per ewe) in the final weeks of pregnancy, rising to 20% to 21% for higher-prolificacy flocks. Concentrate feed levels will also have an influence in this regard and where high volumes are being fed the protein content can be adjusted downwards. The overall feed value of the concentrate should ideally be in the region of 12 MJ ME/kg DM or 0.95UFL as fed or greater.
Having a flock of ewes that are in good body condition should be viewed as a resource that is important to protect. The reasoning behind this statement is straightforward. It takes a significant feed resource to bring about an improvement in ewe condition. The cost of this feed resource is significant at all stages of the year, but it is particularly expensive during the winter months.
For example, it takes a lowland ewe anywhere from eight to 12 weeks to gain one condition score (10kg to 12kg liveweight) on good-quality grass. This is the most economical route of gaining condition, with the cost much higher where supplementary feeding is the route for this gain.
For this reason, it is important to protect ewe condition now and over the next couple of months to be in a position to exploit it in late pregnancy and early lactation when it will deliver the greatest benefit in both underpinning performance and reducing costs.
The quality of silage on offer will have a profound effect on animal performance and also have a direct influence on winter feed costs.
Stage of gestation
The nutritional requirements of ewes will differ significantly depending on the stage of gestation. For ewes in early pregnancy, it is vital that they are maintained on a high plane of nutrition to promote embryo attachment to the wall of the uterus and prevent early embryo loss. This is important for the first four weeks of gestation.
After this, feeding can be targeted at maintenance levels or slightly below maintenance levels for a period. Research has shown that a small level of weight loss in mid-pregnancy can have a positive influence on placental development and, in turn, ensure optimum delivery of nutrients to the developing foetus(es). The critical words in this sentence are a “small level of weight loss” and this should be limited to a maximum of 5% of bodyweight.
It should also only take place where ewes are in a body condition score which facilitates it to occur. Lowland ewes should enter late pregnancy in a body condition score of at least 3 and preferably higher, while hill ewes should ideally have a condition score of at least 2.7.
For many mid-season lambing flocks, feeding a maintenance diet should now be the focus. The size and weight of ewes will influence the maintenance feed levels, with a 70kg ewe in mid-pregnancy requiring 0.8UFL to satisfy maintenance demands. This can be adjusted accordingly for heavier or lighter ewes.
Early lambing ewes entering late pregnancy will require a rising plane of nutrition in the final six to eight weeks of pregnancy to satisfy a sharp increase in ewe energy requirements. \ David Ruffles
Feed quality
Despite utilisation suffering in recent weeks, grass reserves are still in good shape on medium and lowly stocked farms and access to moderate-quality grass such as cleaning off paddocks or deferred grazing will meet maintenance demands. Highly stocked farms have a lower grass reserve built up but should still be in a position to sustain ewes outdoors until early to mid-December or possibly later, depending on grass utilisation.
If ewes remain outdoors until well into the new year on deferred grazing, they will generally need access to between 1.5kg and 1.7kg grass dry matter to deliver in the region of 1.15kg to 1.3kg grass DM at 75% utilisation.
Table 1 details the feed value of silage and hay at varying levels of dry matter digestibility. The difference in feeding value should serve to highlight the importance of getting silage tested well in advance of when it will be required, so that an accurate feeding programme can be put in place. Many merchants will facilitate silage testing, as will advisers and consultants.
Access to moderate- to good-quality silage of 67DMD to 70DMD will be fine for ewes in good body condition during mid-pregnancy. As long as protein levels are also reasonable (11% to 12%), then no supplementation apart from the exception of mineral/vitamins, if required, is necessary.
Silage intake
Ewes will need to consume about 1.1kg to 1.2kg silage dry matter, equivalent to 5kg silage freshweight at 20% dry matter or 3.5kg to 4kg freshweight at 25% to 30% dry matter. Poor-quality low-digestibility silage will depress intake in ewes and leave them unable to physically consume enough silage to satisfy nutritional demands.
For example, if silage is below 60 DMD, has been ensiled wet and, as a result, preserved poorly, ewes will at best only be capable of consuming 0.6kg to 0.7kg DM. Combined with the poorer feed value, ewes offered such silage will only be receiving 50% to 60% of their daily nutritional requirements. The long-term consequences of such a scenario are serious, with weight loss of up to 1kg or higher per week. As already mentioned, identifying issues like this well in advance of supplementary feeding being required will allow alternate plans to be put in place.
The manner in which silage has been saved will also have an effect on ewe intake potential as demonstrated in Table 2.
Ewes fed precision-chop silage will be able to consume higher volumes which, in turn, will reduce the volume of concentrate supplementation required in late pregnancy.
Hay typically has a lower energy value but where it is good-quality, ewes can compensate somewhat by consuming higher volumes. Some reports suggest silage is testing below anticipated, with silage made late in the year preserving poorly in cases or having a low dry matter content. This raises the importance of accurately identifying the quality of silage on hand.
Late pregnancy feeding
The body condition score of ewes continues to hold major significance in late pregnancy. Research shows that a 0.5 unit reduction in BCS in the final month of pregnancy can impair lamb survivability to the tune of 5%. The research also highlights the downside of ewes entering late pregnancy in poor body condition, with each drop of 0.5 in condition score below BCS 3 at lambing reducing lamb survivability by 5%.
This is not to forget the negative consequences on lamb birth weights and vigour and the quality and quantity of colostrum produced. Early lambing flocks starting to lamb from the end of December are entering the critical final six- to eight-week period. During this time, energy requirements for a twin-bearing lowland ewe follow a sharp upward curve, rising from 12.2MJ ME/kg DM to 20.2 MJ ME/kg DM, while the protein requirement also jumps to 137g of metabolisable protein in the final week of pregnancy.
High-energy diet
The universal concentrate supplementation guide based on varying silage quality is detailed in Table 3. Where dealing with very poor-quality silage, this should only act as a roughage source in late pregnancy. It is also unsuitable for an early lambing production system where ewes and lambs are likely to be maintained indoors for a significant period post-lambing. If this is the case, then an alternative source of forage should be sourced in the coming weeks.
It should also be noted that the feeding programme in Table 3 can be used as a blueprint for farmers participating in the Sheep Welfare Scheme who selected the optional measure of ultrasound pregnancy scanning.
When selecting concentrates for feeding ewes or finishing lambs, it is important to ensure that it is formulated with high-energy ingredients. Table 4 is a useful guide to the energy and protein content of regularly used ingredients.
Feeds must list their ingredients in order of inclusion levels. The high-feed-value cereal ingredients should form the foundation of the feed and alarm bells should ring where ingredients with a low-energy rating are located towards the top of the ingredient inclusion listing.
In terms of protein, the general recommendation is a concentrate content of 18% to 20% for medium litter sizes (1.6 to 1.9 lambs per ewe) in the final weeks of pregnancy, rising to 20% to 21% for higher-prolificacy flocks. Concentrate feed levels will also have an influence in this regard and where high volumes are being fed the protein content can be adjusted downwards. The overall feed value of the concentrate should ideally be in the region of 12 MJ ME/kg DM or 0.95UFL as fed or greater.
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