Beef and sheep notes June 2008

Quality Swards

Beef cattle will gain over 1KG liveweight on highly digestible swards during the summer months. Pastures which contain a high proportion of green leaf will have the highest digestibility.

Material	Digestibility
Green Leaf	70-85%
Green Stem	60-70%
Mature Stem	40-50%
Dead Material	35-40%

Therefore, grazing leafy material and preventing seed heads from developing is very important in sustaining sward quality. Grazing swards down to 8-10 cms in early June generates more leafy material in later cycles. As a result of close grazing, surplus grass may accumulate ahead of the cattle. If so, this should be removed for silage as big bales. Topping will also over-come the problem of stemmy swards, provided it is carried out early in June to a height of 7 cm (3”).

Making Round Bale Silage

Due to the recent escalation in input costs, the fertiliser and harvesting costs alone of producing a round bale of silage is likely to increase to approximately £15 per bale. This is based on obtaining a yield of 25 bales per hectare(10/acre).

It is therefore imperative that every effort is made to produce good quality, well preserved silage while keeping the number of bales made per hectare to a minimum.

Avoid cutting grass too low to avoid contamination.
A fast wilt, where practical, will aid preservation and also reduce the number of bales per acre. Aim for 30 percent dry matter within one day.
To achieve a fast wilt, use a mower conditioner to cut the crop and/or tedd immediately once the crop is cut (weather permitting).
Produce dense, broad ‘shouldered’ bales by presenting a box – shaped swath for the baler.
Using a chopper baler will reduce the number/cost of bales per acre.
Ensure that the contractor has the baler density set to its maximum allowable position and travels slowly along the swath.
Harvest leafy material – saves on expensive meal.

Value of clover

Clover swards are particularly suitable for grazing on many farms where low levels of nitrogen fertiliser are used. The average nitrogen fertiliser use on NI beef and sheep farms is approximately 120KG nitrogen per hectare. An equivalent level of production can be achieved from clover based swards.

Clover swards lose quality more slowly than grass, dropping about two units of digestible value each week. This contributes to greater herbage intake. Up to 10 percent higher liveweight gain in cattle and 25 percent higher liveweight gain in lambs

The production of swards can vary from year to year, but clover based swards could be expected to support up to two livestock units per hectare per year. This is equivalent to 2,000 – 2,400KG animal liveweight per hectare in the spring, declining to approximately 800 – 1,100kg per hectare in the autumn.

Establishing clover in swards

Direct reseeding - Plough before the end of August and use25 KG of perennial ryegrass with 4-5 KG of clover seed, sown at about 30KG per hectare.

Overseeding methods can be used to place seed into an existing sward. Techniques such as direct drilling using the Vertikator, very light cultivation followed by sowing with an air seeder such as the Einbock, or discing ground and broadcasting the seed have all been used successfully.

In all cases it is essential that competition is minimised by grazing the sward tightly (4-5cm) in late July, or by following immediately after a silage cut taken mid-July to late August

Dosing sheep

– Resistance to worms is increasing

More evidence of sheep wormers particularly the white drenches becoming less effective because of anthelmentic resistance.

Proper dosing techniques will slow down build up of resistance. The following guidelines will help.

Correct dosing practice – know the weights of lambs.
Use the most appropriate anthelmentic.
Only dose when necessary. Avoid dosing adult ewes during the grazing season except hogget ewes or individual thin ewes.
Use of clean pastures where possible.
Leave 10 percent of lambs undosed that is, the heaviest and healthiest lambs.
Delay movement to clean pastures for several days after dosing.

Use faecal egg counts to indicate need for dosing – your sheep adviser has a kit for this purpose.