How to hit protein needs when outwintering ewes on brasiccas

Sheep farmers could reduce the cost of winter feed and housing by grazing pregnant ewes on brassicas in the run up to lambing, but close attention should be paid to ensure protein intakes are sufficient.

For Carmarthenshire hill farmer Irwel Jones, one of the greatest challenges of outwintering pregnant ewes on brassicas has been maintaining their protein intakes.

Mr Jones, who farms with his parents, Eirwyn and Heulwen, grows 4ha of swedes as feed for 280 twin-bearing ewes in the two months leading up to lambing, which starts the first week of March.

He first introduced the crop into his system at Aberbranddu, near Pumpsaint, to gain valuable points for joining the Glastir environmental land management scheme.

There was another key advantage.

See also: Home-grown forages can cut sheep feed costs

“It was a feed we could grow ourselves to utilise during a time of the year when grass growth on the farm is not sufficient to maintain the flock.

“Up until then we had been housing these ewes or keeping them at grass and supplementing with silage and concentrates,’’ recalls Mr Jones, a member of the Farming Connect’s Measure to Manage benchmarking group.

Crop establishment

This year Mr Jones is growing the swede variety, Invitation. The seed was broadcast on 21 June, at a rate of 1kg/acre (2.5kg/ha). The seed cost £44/acre (£110/ha) and ploughing £39/acre (£97.5/ha).

The ewes are turned on to the crop in January and graze through to the end of February. “It takes the ewes a week or two to get used to the crop but after that they go mad for it,” says Mr Jones.

Mr Jones runs a flock of 980 Tregaron-type Welsh Mountain ewes. Only the ewes carrying twins are grazed on the swedes.

“The lambs of the single-bearing ewes would get too big and cause difficulties at lambing and it would not be a good idea for the triplets because the conditions can get slippery under foot,” he says.

The remainder of his flock either grazes lowland ground on tack, is housed or is fed silage outside.

Meeting protein requirements

Mr Jones says in previous years the challenge has been to get enough protein into the ewes before lambing because the field was too muddy to offer pellets.

“We used protein blocks last year but the quality of the colostrum from the first ewes to lamb wasn’t as good as it should have been.”

This year he has the advantage of a track running between the crop and the grass runback and plans to feed protein pellets from this.

Ewes receive a 34% protein pellet outside, starting at 100g a head a day and gradually increasing to 350g a head a day three weeks before lambing when the ewes are housed.  

Other

Mr Jones strip grazes the crop to maximise use, with the weather dictating the number of times he moves the fence.

“Last year, when the weather was very wet, I moved the fence every day but if it is frosty I give them a bigger piece and leave them there for a week. More of the crop is wasted when it is wet.”

Mr Jones’ ewes get free access to silage and he provides mineral blocks to prevent trace element deficiency.

“We always have a good runback and offer silage in a sheep cradle feeder.”

Top tips when feeding brasicca crops, by sheep expert Kate Phillips

1. Generally, sheep expert Kate Phillips says brassica crops are quite adequate to feed to sheep alone, but swedes are quite short of protein.

“If you’re running ewes on them right up to lambing, they are unlikely to milk well. You might want to move them on to silage and concentrates or good grass three weeks before lambing to help meet their needs,” she adds.

2. Mrs Phillips advises introducing ewes to root crops gradually to minimise disruption to the digestive system. “They should have full stomachs when they first go into the field, then step up access to the crop by an hour or so a day, so they get used to the new diet slowly.”

3. To achieve up to 80% use of the crop and reduce wastage, strip graze using an electric fence, moved daily.

The strip needs to be long and shallow to allow all ewes to eat along the feed face.

“One thing with root crops is that if the whole field is available, the animals will go in and graze off the tops, which contain most of the protein then come back and graze the low protein roots so they have a low-protein diet later. It’s better to strip graze to have a better balance of nutrition as they go across the field,” says Mrs Phillips.

4. When planning how much to feed, it is important to calculate the dry matter yield a hectare.

To do this, cut five or six metre squares from around the field, put them into a bag and weigh.

Divide by the number of squares taken and then multiply by 10,000 to give tonnes a hectare.

Once the crop yield has been calculated, the area to be made available can be worked out depending on the number of ewes and their energy and protein requirements.

“If a ewe needs 10MJ of energy, this equates to roughly 1kg DM of a crop,” Mrs Phillips explains. “If the crop is 6t DM/ha at 70% use (6,000 x 0.70 = 4,200kg DM) then this could carry 42 ewes for 100 days.

“If ewes need 1.5kg of DM then the calculation is 4,200/1.5, which means the crop could carry 42 ewes for 66 days.”

5. As brassicas have low levels of trace elements, particularly iodine, selenium and copper, it is important to provide a mineral lick or to bolus the ewes. Providing additional fibre is also important to promote healthy rumen function, with silage or hay the best sources for sheep.

“Providing long forage is a good idea,” Mrs Phillips recommends.

“Some brassicas have low dry matter – forage rape for example is about 10% dry matter and turnips about 12-15% – so having dry, long fibre is good for rumen health and helps to maintain dry matter intake when grazing conditions are poor.”

6. A runback – a dry, lying area somewhere in the field where the animals can retreat from the crop and avoid becoming too wet and dirty – is essential, says Mrs Phillips. “You could roll out straw bales as a lying area or have a grass runback,” she suggests.

Eblex has also produced a manual containing advice on establishing brassica crops (PDF).