The increasing cost of farm inputs, namely fertiliser, feed and fuel should encourage a focusing of the mind when it comes to livestock grazing with significant wins available for farmers who improve their management. In this blog we are looking at this in more detail, and have also recorded a video on this which is embedded below.
In Spring, all pasture regardless of age or species composition will provide high quality feed for livestock (providing it consists of mainly green leaf)). Nature has designed this to be the case with the pasture normal analysing at >12MJ Metabolisable Energy, >20% Crude Protein and >20% DM. This high quality and high dry matter mean it is the perfect feed for animals pre or post lambing/calving as well as being suitable for transitioning growing animals onto from winter forages such as silage.
A general aim is to have grazed every field on the farm by the end of April (Dry Farm) or 10th May (Wet Farm). Due to the mild winter, it is worth walking silage fields as many are carrying high covers but also have decaying leaves which, if left un-grazed will reduce first cut quality. The decision to graze will depend on your system but if the option is to turn out to graze the silage fields or keep cattle in on silage, then the option should always be to turn out!
For lactating animals, it is key that they are “fully fed” up to and at peak lactation. For ewes peak lactation occurs 3 weeks post lambing and for cows its 6 weeks post calving. The milk produced at peak sets the total volume of milk produced in that lactation which means it has a big influence on the weight of lambs / calves at weaning or annual milk yield per cow.
These lactating animals are the highest priority on farm, they should be fed to appetite (where possible) and pasture height monitored. Sheep and beef breeds of cattle can reach their peak yield from forage alone. Therefore, the only time a concentrate feed would be justified is when pasture quantity is in-sufficient; for ewes this means less than 5cm average pasture height and for cows less than 10cm average pasture height. At these heights the animals cannot consume enough pasture per day to meet their genetic potential. For some dairy breeds concentrate feed may be justified if the increase in yield exceeds the cost of the feed.
Mostly this stock class will either be growing / finishing cattle or replacement heifers. With these animals the aim is to transition them to pasture so their rumen is fully adjusted before peak pasture growth arrives (May). This means that when conditions allow these animals can be fed ad-lib, consuming as much of the low-cost pasture as possible to efficiently convert it into liveweight gain at a very low cost.
To aid this transition process it is recommended to step-down any concentrate feeding over a period of 4 weeks towards 0kg and ideally to allow the animals time to adjust by letting them out by day and in by night if the situation allows. Concentrate feeding at pasture to native breeds (pure or dairy cross) or replacement heifers is not recommended due to current feed cost. Instead, the focus must be on grazing management (see below). For continental breeds, feeding a source of high energy i.e., grain might be required during the finishing phase to achieve suitable fat cover to meet specification.
Increasing Pasture Production
How long animals spend in one field is the single factor which has the greatest influence on the amount of pasture grown (tonnes Dry Matter per Hectare). Changing the system so that animals move to a new field more often provides the plants with a rest between grazing events. This allows them time to replenish their energy reserves and re-grow ready for the next grazing event.
As the table below shows, moving from set-stocking to rotational grazing can increase the total pasture grown by 4tDM/ha and pasture utilised (eaten) by 3.3tDM/ha! This is equivalent to applying 220kgN/ha (5 bags/acre) at a cost of £410/ha (£160/Acre)*.
|Grazing Management Technique||No. of Days / Paddock||Annual Yield (tDM/ha)||Utilisation (%)||Pasture Utilised (tDM/ha)||% increase (from set stocking)|
|Continuous (Variable)||10 - 20||8.5||60||5.1||20%|
|Rotational Grazing||3 - 6||10.2||75||7.6||56%|
|Adaptive Multi Paddock Grazing||1 - 2||10.2||80||8.2||92%|
Table 1 – Pasture yield and utilisation under different management techniques. Source: AHDB. 2020. Planning Grazing Strategies for Better Returns. Available online: https://ahdb.org.uk/knowledge-library/planning-grazing-strategies-for-better-returns
In order achieve a rotational grazing system each group of animals needs to have access to a minimum of 5 fields or paddocks. Moving every 4-6 days means a rotation length of 20 - 30 days and rest period of 15 - 25 days which will be suitable for most of the growing season (April-October). If the group cannot graze a field down to a suitable height within 6 days, the field should be split in half or as required with temporary electric fencing (or other materials). If you don’t have enough fields then consider combining groups of animals together or dividing more fields in half.
For artificial nitrogen to provide an economic return at current prices the response rate (kgDM grown per kgN applied needs to be better than 12.5. To achieve this requires good conditions meaning; new or improved leys, PH>6 and P&K Index 2 or above and soil temperature above 8 degrees. When this is the case it is important to apply the right amount i.e. what the plant needs. Recommended application rates based on soil temperature are:
- 8-10⁰C Max 20kgN/Ha
- 10-12⁰C Max 30kgN/Ha
- 12⁰C Max 40-50kgN/Ha
You can measure soil temperature using a garden thermometer, best time to measure is 10am from a representative part of the field at depth of 100mm (4”). It is also recommended to leave a strip un-spread to assess the impact the application had. If pasture is measured using a plate meter the strip can be used as a “control” area to calculate the actual benefit.
With nitrogen, as with all farm inputs in 2022 ask yourself - “if I use this input, what will my return on investment be?”
This topic has also been discussed in a YouTube video with James Daniel and Phil Pengelly - watch it below and download the slides that were used in the presentation here.
Precision Grazing Ltd
* Based on kgN/kgDM efficiency of 15:1, Ammonia Nitrate at £650/t