Sheep Farm Management Notes: 01/06/2010
Managing Grass to Keep Lambs Thriving
A burst of grass growth, as we have seen over the last week, always makes it more difficult to manage grass. The key is to react quickly. The target for grazed out swards on sheep farms in May is 5 centimetres. In June, the aim should be to graze down from 8cm to 6 cm and if you are operating on a set stocking rate, then try to keep it at 7 cm. Now is the critical time for managing grass to maintain a quality pasture through the rest of the summer. Keeping lambs thriving is all down to grass management. It is also a key component in the cost of finishing lambs as the more lambs that can be finished off grass, and the more weight gained from pasture, the more profit for you. Research on creep grazing lambs ahead of the rest of the flock, shows that this can increase weaning rate by 2 kilos.
When you have enough grass on the grazing area to last at least 14 days then you should look at removing some of it by taking out a field for silage. When pre-grazing grass covers exceed 8 cm (1,100kg/ha) silage is then the best option. The after-grass on the area where this silage is cut will be invaluable for getting lambs to maintain thrive later in the summer. It will also help to rebuild feed stocks for the coming winter, after the long and cold winter and spring we have just experienced.
Shearing Started
As well as improving grass growth, the rise in temperatures has kicked off the shearing season and also brought the first of the blow fly strikes on farms. Shearing has started in many of the lowland flocks in the south and eastern parts of the country. The rise in temperatures has made the task a bit easier with the oil rising in the wool. It has also increased the risk of blow fly strike in sheep with heavy fleeces that are dirty. So getting it off this kind of stock early can have an added benefit. The value of wool has increased considerably this year compared to the past few years, 75 – 80c/kg compared to 40 – 45c/kg last year. It is important to handle wool carefully to maximise its value. Shearing sheep that are damp can lead to deterioration in the quality of the wool, so it can be a good practice to have sheep housed from the night before to ensure they are dry. Most sheep producers got plenty of practice at that last year given the changeable weather pattern. Eliminating dirt and preventing straw, twine and other foreign objects is also stressed by the wool buyers. If you have all your own sheep shorn or you just want to go along and see some of the experts performing, an event that will be worth a visit is the All Ireland Sheep Shearing Championships that are taking place in Portlaoise Rugby club on Saturday and Sunday, 5 and 6 June.
The first cases of fly strike have been seen in lowland flocks, mostly in ewes. Shearing will help to deal with this. Controlling blowfly strike is critical for all flocks as affected lambs will suffer a set back in growth. Dipping and pour-on products are the two options.
When comparing treatment options for the prevention of blowfly strike (maggots) check:
- cost per animal treatment,
- the length of the protection period, and
- the withdrawal period.
In the past, plunge dips were the cheaper option but gave a relatively short protection period of 4 – 8 weeks. This year there is a reduction in the cost of some pour-on products and these can give protection for up to 16 weeks. However, some of these products can also have withdrawal periods of up to 40 days.
