Make the most of forage

SAC Livestock Business Consultant

Feeding the pregnant ewe can change year on year, dependant on the weather, condition of the ewe, number of lambs being carried, stage of pregnancy and grass availability – all of which have to be considered on the run up to lambing.

Ewes in mid-pregnancy can be incredibly resilient; from three weeks after the tup has been removed, until six weeks pre-lambing, their feed requirements are at their lowest. They only need to maintain their own weight and condition at this time. This presents an opportunity to make the most of the available grazed grass and/or the conserved forage – they can be put on a diet.

Grazed grass is top choice and don’t be frightened to graze it tightly. At this time, they can graze down to 3cm. This also makes for better quality spring grass growth. If practical to rotationally graze, do so. This is the best way to stretch out grass supplies.

Wet weather is a challenge, but pasture that has been grazed hard for a short period of time will recover when rested.

Average hay (9MJ ME/kg DM, 10% CP) will also meet their demands at this time without additional energy and protein needed from blocks or rolls. Feed space is important, ring feeders are designed for 24 ewes. If they don’t have enough space, it may look like they are all getting a feed, but the shy feeders will be getting the poorest quality pick and will be at risk of losing weight.

Concentrate feeding is a back-up in bad weather. However, they need to know what it is. Training is best done when they are hoggs as this is when they are most curious. Hoggs in a small field given 150-250grams/head over a couple of weeks will give them the right idea providing there isn’t something better on offer, such as lush grass. Mixing trained ewes with others encourages any inexperienced sheep to eat.

The key to all this is monitoring. Restricted feeding is not cost-effective if they lose too much condition and then have issues at lambing time. However, with the mild December, some farmers may have more grass than normal, make the most of it.

Target nutrition for lambing success

In terms of nutrition, the last six weeks makes a huge difference to lamb survival as this is when the foetus does most of its growing.

Under feeding at this time risks smaller, less vigourous lambs and impaired mothering behaviour.

Consider energy first. Energy fuels rumen microbes which convert dietary protein into protein the ewe can utilise. High energy forage is best. Grazed grass can meet all their energy and protein needs providing there is enough. This is only an option for those lambing in late April/May.

The next best option is good quality silage. The more of their energy demand that can be met from forage, the better for rumen health.

High energy supplements are usually high in starch. Starch causes the rumen pH to plummet to a level where cellulose digestion halts. This means that the ewe’s energy supply could become deficient. Consider the energy supply of the forage and supplement accordingly. If using straights, consider those that are low in starch such as sugar beet pulp, oats or whole barley. Analyse the ingredients on ewe rolls, looks for those which have maize, barley or wheat high on the list as indicators of high energy feeds.

Prevent excessive intake in the greedy ewes by allocating sufficient trough space (45-50cm/ewe) and providing two feeding intervals when the concentrate requirement exceeds 0.45kg/day. Well managed Total Mixed Rations (TMR) feeding is best for maintaining healthy rumen pH and reducing stress.

When protein levels in the diet exceed 12% crude protein (CP), there is sufficient rumen degradable protein for rumen function. However, we can boost protein supply with digestible undegradable protein (DUP). DUP bypasses the rumen and is absorbed more efficiently in the intestine. If ewes are in good condition and the silage quality is more than 10.5 MJ Metabolisable energy and 12% CP, consider targeted DUP feeding in the last four weeks using soya at 100g/lamb carried or protected soya at 50g/lamb carried.

The last six weeks makes a huge difference to lamb survival – feed them well to give them the best odds this year.

Feeding post-lambing

The first few weeks of a lamb’s life will set the scene for its performance; younger lambs are most efficient at gaining weight and they are getting the best quality feed they will ever get – their mother’s milk. Ewe management at this time is highly influential to the lambs weaning weight.

Fortunately, this is where spring grass yields benefits. Spring grass is high in energy and has a surplus of protein. When there is more than 4cm of grass, the ewe will be able to lactate well to keep those lambs growing.

Early nitrogen will boost spring grass supply and is far cheaper than feeding concentrates. Weigh up whether nitrogen is required and apply when soil temperatures exceed 5oC for five consecutive days. Ewe condition is also highly important here, if she has the fat reserves, she will utilise them to produce milk.

However, following spring 2018, it is important to have back up options if grass doesn’t grow early on. When grass height falls below 4cm, the ewes and lambs will benefit from additional feed.

At 3.5cm grass height, provide 0.4kg concentrate/ewe/day, below 3.5cm grass height, feed 0.7kg concentrate/ewe/day and additional forage will be needed for fibre.

Concentrate feeds should be high protein and energy.

The converse is that spring grass can be too lush. This means it passes through the ewe quickly and grass staggers could become an issue. In this instance, provide roughage alongside magnesium blocks.

Initial growth rates of lambs are dictated by ewe condition and feeding – get them going early on to sell them sooner and/or achieve higher carcase weights.