The second in a series of articles on fodder beet looks at how the crop can be an efficient way of wintering large numbers of sheep in a small area, helping save pasture elsewhere. Hannah Park reports.
Fodder beet can be an easy, safe and productive feed for ewe and ewe lamb wintering if close attention to detail is paid when it comes to crop quality, allocation and animal health.
Dr Jim Gibbs, vet and research scientist in rumen nutrition at Lincoln University, New Zealand, said these were key considerations for sheep farmers looking to over-winter sheep on fodder beet in recent AHDB organised webinar series on fodder beet systems.
If done right, he said, incorporating beet grazing into ewe wintering plans could yield considerable cost and efficiency gains, given the crops high energy output and a general minimal requirement for supplements to be fed alongside.
Dr Gibbs said: “In the case of wintering pregnant ewes, agronomically well-grown beet crops do an excellent job of meeting input requirements of multiple-bearing ewes without difficulty during a period where other forages are lacking.
“Additionally, little or no additional supplement feed input may be required for sheep grazing a well-grown beet crop, provided the leaf is there and makes up roughly 25 per cent of the dry matter of a crop which holds well into winter.
“In instances where it is lower than this, some high quality, high protein supplement provision will be required, allocated correctly so it is accessible to all animals in a group.”
As with other livestock classes grazing fodder beet, strip grazing the crop is necessary to ensure animals are eating it in the right way.
But particularly important for sheep is beet variety choice as well as crop agronomy as a management tool given the way they eat it.
“The distance and mass of bulb that is in the ground varies between fodder beet varieties, as does palatability,” Dr Gibbs said.
“Sheep do not typically pull the bulbs out of the ground. They eat them in place. So the further they are into the ground the less of the total bulb they will eat.”
This does not have to impacton utilisation however, Dr Gibbs explained, with it being common practise that those bulbs are later popped out of the ground and fed to another livestock class towards the end of the season, once grazing ewes have been over the crop.
“There is also a sensitivity to palatability for sheep,” Dr Gibbs explained.
“Although intakes will typically be higher on more palatable varieties, it is possible to override variety preferences in some cases with agronomy by shifting inputs to change the nitrogen content of the bulb – to increase crude protein content of the bulb and to increase both the amount of and nitrogen content of the leaf which will drive intakes.”
Unlike cattle, sheep do not have the same issues transitioning onto the crop.
In general, it is therefore sufficient to run ewes on and off the crop for a couple of hours for a few days before they go onto it fully.
“Time to total intake for sheep is almost identical to what it is in cattle, but because they regulate their intake in a different way, it is extremely rare to see clinical acidosis in sheep or animals that have been induced into feed aversion by sub-clinical acidosis,” Dr Gibbs said.
The strategy behind allocation is however very different to cattle, said Dr Gibbs.
“It is crucial not to over-allocate for sheep,” he said. “Doing so will drive them to keep eating the leaf and a minimum part of the bulb. You want to match the intake of leaf with bulb to meet intake requirements.
“Under-allocating, however, does not automatically drive sheep to eat further into the ground.
“At a certain point they will stop eating, which will result in a poor quality diet and restrict production.
“As a general rule, allocation should work out at about 3 per cent of ewe weight in dry matter per day, although more attention to detail may be needed around transition to make sure intake of bulb and leaf is balanced.
“For sheep it is common to go beyond daily breaks, although stretching beyond three days breaks is likely to lead to an in-balance in energy and protein intakes.”
Sheep, like younger cattle, are highly susceptible to clostridial disease while on the crop and losses can be an issue if vaccination is not up to date before going on.
A drench and trace element top up, in-line with regional requirements, is also required ahead of this.
Fodder beet can also be an effective winter diet for hoggets or ewe lambs, if careful consideration is given to the variety, crop agronomy and supplement provision.
“These animals are much more sensitive to the protein and energy balance they are provided with,
imbalance can quickly reduce their bulb intake and result in intake requirements not being met,” explained Dr Gibbs.
“Careful supplement allocation and provision in most cases is required.”
Lamb finishing, he continued, is not typically a viable option on fodder beet, as crude protein requirements here are too high here.
“Beet has to form the majority of the diet for the system to be viable – therefore achieving desired liveweight gains here cannot be done without expensive and difficult supplement input that will often make the system counterproductive,” he said.
“Issues around palatability and susceptible to clostridial disease are also highly exacerbated in lambs.”
A straightforward and viable alternative, Dr Gibbs said, would be a pasture and bucket beet system whereby animals would be strip grazed and a 50 per cent pasture input and 50 per cent beet input established in terms of required dry matter in the diet.