The spike in grass growth rates in recent weeks is a positive development for farmers. For example, growth this week has been recorded at over 60kg DM/ha per day on Tullamore Farm with the farm continuing to build autumn grass supplies but still falling short of its target of an average farm cover (AFC) of upwards of 1,000kg DM/ha.
The AFC is currently above 800kg DM/ha and if growth remains above the norm and steps to reduce demand are taken including weaning strong calves, it should put the farm in a good position to have enough grass for ewes until well into December.
The spike in grass growth has provided farmers worst affected by drought and facing the prospect of an earlier end to the grazing season and possibly a deficit in forage supplies with an opportunity to hopefully get back on track.
For others who already had a good supply of grass available, it has resulted in some very heavy covers of grass developing. The potential to achieve high levels of grass utilisation on these swards will depend on rainfall levels in the coming weeks and management practices taken to optimise utilisation.
Current situation
Before delving into management of these paddocks it is worthwhile to take stock of current supplies and put a rough autumn grazing plan in place including highlighting priority stock to offer the best-quality grass to.
The target for the end of September is to have at least 30 days grazing ahead of stock. What this essentially means is that if growth stopped in the morning there would be enough grass present to sustain stock numbers on the farm for 30 days.
If there is a deficit foreseen then steps must continue to try to build grass supplies while growth is running above normal. This may include reducing grass demand from lambs by feeding higher levels of concentrates or taking advantage of a positive trade for store lambs.
Grass supply information will be readily to hand for those measuring grass but even where this is not practiced there is still steps that can be taken to inform plans.
The majority of farmers have a rough idea of the area of lands in different fields or parcels.
Table 1 details the number of grazing days for a range of grass covers based on 100 ewes grazing a one hectare plot and offered 170kg DM/day.
The grass allocation of 170kg DM/day works on the premise of each ewe receiving a daily grass dry matter allocation of 1.7kg DM per ewe daily and consuming 1.3kg to 1.5kg grass DM depending on utilisation levels. Typical utilisation in October, November and December is in the region of 75% to 80% and is lower on more marginal lands or during inclement weather.
Grazing targets
The best option where heavy covers of upwards of 2,200kg DM/ha have developed will typically be to graze these as soon as possible while higher levels of utilisation are possible.
The exception to this is where these covers are present on drier areas of the farm and more marginal or wetter areas would benefit from grazing first.
It is not always readily feasible but the best approach when grazing heavy covers is to split the available area into two-to-three day grazing blocks.
In this situation ewes will graze the best-quality grass first and then be forced to graze lower quality material for a shorter period before returning to better quality grass.
If ewes are given access to the entire area then this will result in the best-quality grass being consumed and then ewes being forced to graze lower-quality material for a sustained period.
Such an approach is acceptable where ewes are gone beyond the first month of pregnancy and are in good body condition.
Another option is to maximise the size of the grazing group so that defined areas can be grazed out quicker.
In terms of allocating grass ewe intake requirements will be in the region of 1.5kg to 1.6kg DM/ha in the run up to and during breeding.
This will reduce back closer to 1.3kg DM/ha later in the season or for early lambing ewes which are in mid-pregnancy. Where grazing heavy covers coincides with breeding and it is not feasible to split the area into paddocks then the next best approach is to move ewes on without being forced to graze lower-quality material which may affect reproductive performance and then return at a later stage when their nutritional requirement has reduced and the sward has had a chance to freshen up.
Closing targets
Remember also to stay on track with closing targets. Teagasc advice on closing targets for flocks operating a mid-season lambing enterprise at a medium-to-high stocking rate (10 to 12 ewes per hectare) is to have 20% of the farm closed by late October, 40% by mid-November, 60% by late November and 80% by mid-December. This will typically provide a rest period of 120 days giving paddocks first closed an opportunity to have a reasonable cover of grass on swards while growth is still relatively good.
Grazing practices
Where using temporary electric fencing to split paddocks and dealing with sheep not readily accustomed to it then it is best to start out with confining ewes to a smaller area with four rows of wire as opposed to three.
The voltage from a battery fence in particular should just cover this area so that sheep become accustomed to the fence at the outset as if bad habits are learned at the beginning it will be harder to manage thereafter.
Using some timber posts or placing PVC posts or pigtail posts with insulators closer together at the outset will also help greatly. The space between posts can then be increased thereafter.