The quantity and quality of fodder available on farms is hugely varying.
Some farmers who thought they had sufficient fodder available are finding supplies could be tighter as a result of grass reserves diminishing faster and feeding starting at an earlier stage than normal. Other farmers who did manage to save sufficient supplies are being forced to contend with suboptimum quality due to weather delaying harvesting. Other farmers are in a good position with fodder but are tight on straw.
Here we will look at the first two issues of inadequate supply and poor quality.
The starting point in overcoming these problems is to establish what the situation is. A ewe on average will require 1kg dry matter daily to meet demand, so a 100-day winter ewe will require 100kg silage dry matter. The volume of silage a ewe requires on a freshweight basis can vary greatly depending on its dry matter content.
For example, a ewe will require 500kg silage freshweight at 20% dry matter for a 100-day winter, reducing to 330kg silage freshweight at 30% dry matter. A bale of such silage weighing 650kg at 30% dry matter will feed 100 ewes for two days or 50 ewes for four days. Counting the number of bales available and doing a simple calculation will deliver benefits even if a more complex feed budget is not being carried out.
The quality of silage will also have an effect on potential intake, with ewes struggling to eat sufficient quantities to meet nutritional requirements where silage is of very poor quality and a low dry matter. The starting point therefore should be to get your silage analysed to know exactly what you are dealing with. Where an estimate is being used, it is important not to overestimate its quality as this will only lead to a ewe’s nutritional requirements not being met.
Varying demand
The nutritional requirement of ewes vary greatly during pregnancy.
The aim is to maintain body condition in mid-pregnancy, while in late pregnancy the aim is to meet the nutritional demands of ewe maintenance and a rapidly growing foetus or foetuses.
Research shows that a small level of weight loss in mid-pregnancy can have a positive impact on placental development and in turn ensure optimum delivery of nutrients to the foetus or foetuses. This, however, should only take place where ewes can afford to lose some body condition and still enter late pregnancy feeding at a body condition score (BCS) of 3 plus.
As with concentrates, you should study the label to assess the energy content of the feed
Where lowland ewes are currently falling below target condition and range from BCS 2.5 to 3, then the focus should be to improve body condition in mid-pregnancy as it will be very difficult to regain condition once ewes enter late pregnancy.
These animals (which should only be a small percentage of the flock) should be prioritised for remaining grass supplies or the best-quality silage.
Where both of these are deficient, then there will be no option but to introduce supplementary feed.
Where ewes can afford to lose weight, the level of weight loss should be limited to a maximum of 5% of body weight. Ewes in BCS 3.5 to 3.75 can be used to clean off paddocks or be offered silage of 68DMD.
Lowland ewes in excessive condition with a BCS of 4 plus can be made to work a little. These ewes can afford to lose half a condition score or 4kg to 6kg liveweight depending on breed. Weight loss should be gradual and grazing off average- to poor-quality grass or silage of 65DMD to 68DMD will suffice.
As is the case with all groups, condition score should be monitored regularly, with animals switched between groups as necessary.
Trials carried out in UCD show that severe underfeeding in mid-pregnancy will reduce lamb birthweight and subsequent performance. Likewise, significant over-feeding will reduce placental development, reduce lamb birthweight and lead to lower intake capacity in late pregnancy and potentially greater lambing difficulties.
Satisfying demand
Table 1 details the energy provided by varying quality silage.
Hay is of lower quality than silage, but if it is good, hay ewes will compensate somewhat by having a higher dry matter intake.
A 70kg ewe in mid-pregnancy at the correct BCS will require 0.8 UFL to meet maintenance demands, with the requirement increasing/decreasing by 8% to 10% for heavier 80kg ewes and lighter 60kg ewes.
Access to a good supply of moderate-quality grass will meet these demands, as will access to ad-lib silage of 67 to 70 DMD. If silage is at the higher end of the range and in the region of 11% to 12% crude protein, then no supplementation apart from minerals/vitamins will be required until ewes enter late pregnancy.
Issues start to occur with poor-quality silage. Some farmers are faced with very poor-quality silage (60DMD or lower) and the big concern here is that as well as not meeting nutritional demands, intake will be depressed and ewes will not physically be able to eat enough to meet nutritional requirements.
For example, where quality is below 60 DMD and silage is wet, ewes will physically only be able to consume about 0.6kg to 0.7kg DM, which at such a low quality means ewes are only receiving about 50% to 60% of their daily nutritional requirements.
Offering an alternative energy source such as feed buckets, molasses or a low level of concentrates will bridge the energy gap.
The level of concentrates required ranges from 0.2kg to 0.6kg depending on silage quality and ewe condition.
If this is not addressed, the level of weight loss can be in excess of 1kg liveweight per week which if left unaddressed over a period of time can have big consequences. Where silage quality is poor, ewes should also not be forced to consume all they are offered as this will further hit intake. Splitting feeding to twice daily where possible will also help to lift intake by 20% to 25%, with ewes eating more when offered fresh silage.
As detailed in table 2, late pregnancy feeding will also need to commence much earlier with poor-quality silage.
Very poor silage – is a high concentrate diet the answer?
Where silage quality is very poor or is scarce, then a high-concentrate diet may offer more stability. It should be noted at the outset that operating such a feeding system requires high levels of management and facilities that allow all ewes to comfortably eat together.
A high-concentrate diet is most commonly offered in late pregnancy but a number of farmers also offer ewes a high-concentrate diet in mid-pregnancy, with Tyrone farmer Isaac Crilly previously featured on the sheep pages. His experience with feeding ewes a soya hulls-based diet can be read by clicking here.
The diet should be formulated in a manner that supplies the required level of energy and protein and fed at a level that satisfies a ewe’s nutritional requirements. For example – take a ration with an energy content of 0.90UFL/kg DM to 0.95 UFL/kg DM. Feeding 0.7kg to 0.8kg will meet a ewe’s nutritional demand in mid-pregnancy.
Late pregnancy
When ewes enter late pregnancy, feeding levels in general are doubled on a high-concentrate diet. Research has been carried out by Teagasc and UCD in the last 20 years and found the general recommendation for a twin-bearing ewe in good body condition is 1.2kg in weeks six to five pre-lambing, rising to 1.4kg for weeks four and three and 1.7kg in the final two weeks of gestation. This will increase the total volume of meal fed to between 55kg and 60kg which at a cost of €280/t is about €15 to €17 for concentrate costs alone.
It is also important when feeding such a high level of concentrates to ensure ewes are offered a source of fibre. Straw is the ideal choice, but low availability is more of an issue on some farms than silage supplies are. The quality of straw must be good, which is also a challenge given weather endured during harvesting. Ewes should be offered about 1.5kg per head daily, with some farmers operating the system offering twice the volume and using the straw that is left over as bedding.
This is important, as spreading fresh straw on bedding where ewes are being restricted on forage intake will entice ewes to consume straw bedding and in turn increase the risk of campylobacteriosis from ewes eating straw contaminated with faeces.
The other point to note in late pregnancy is the protein content of the diet, with straw generally low in protein. Formulating concentrates in late pregnancy with a protein content of 16% to 18% will be sufficient for high prolificacy ewes due to the high intake while a protein content of 14% to 15% will suffice for ewes with a low litter size. Remember also to include minerals and vitamins at 2.5%.
The final aspect to take into account is the feeding routine. Ewes should be built up slowly to these levels of meal feeding with feeding split twice daily. Single-bearing ewes will require about 30% lower than the levels detailed above, with triplets requiring 30% extra or practically ad-lib meals.
Energy blocks or feed buckets can be used in extensive grazing systems or in addition to lower-quality forage to increase the overall energy content of the diet. They work out more expensive than concentrates but offer the benefit of significantly reducing labour input.
As with concentrates, you should study the label to assess the energy content of the feed.
Feeding concentrates via a snacker or from the bag can be an option to lengthen the grazing season or again complement poor-quality silage.
It is important to change the feeding site daily and select the driest area of the field where feeding along the ground to reduce the risk of issues such as listeriosis or campylobacteriosis.
Finally, molasses offered at 200ml to 250ml per head can successfully provide an alternative energy source. There are a number of different types of feeders on the market working off the premise of ewes licking a wheel and turning up fresh molasses.
The energy and protein content of molasses can also vary, so it is important to speak with your merchant to determine its feeding quality.
Dealing with a fodder deficit in Cavan