Feeding forage crops

Farming with forage crops

The importance of optimising profit by growing more grass and forage in finishing systems was the message of the day at the Meat and Wool NZ Monitor Farm finishing seminar on forage crops in February.

Click on the links in this list to take you to the appropriate part of the article

Introduction
The farm's feed resource - Tom Fraser
Setting up your system for maximum profit - Roy Fraser
Re-grassing - choosing the right cultivar and endophyte for your farm - Paul Maguire
The latest on high quality forage crops, farm tour - Peter Kemp
Lucerne in a Manawatu finishing system - Bill Hare
Clover, the forgotten resource - John Brock
Highly profitable cattle wintering system - Andrew Ellingham

Trevor Cook (Totally Vets) emphasised the importance of participation by the community group in these days as they are funded by your Meat and Wool NZ levies therefore you are the ones that need to benefit. The Finishing committee aims to select topics for seminars that are relevant to you and get experts to present their thoughts. Feedback from you about interesting topics is appreciated to ensure the programme provided is both relevant and exciting.

Meat and Wool NZ has recently completed their Mid Season Update.  The full report is available on www.meatandwoolnz.com/main.cfm?id=261. This includes summaries and forecasts for the exchange rate, wool, lamb, beef and sheep and beef farm statistics.

Different classes of stock have different requirements at given times of the year. High quality feeds in high amounts are required for production during spring and summer, when pasture growth rates are highest. During mid-October, define the area required for good quality feed for finishing and begin managing covers to ensure they do not get too high and sacrifice summer quality.

The quantity of summer feed is not usually an issue and grazing systems and stock numbers should be examined if there is a problem year after year. Consider a crop for this time of year as grasses are generally not high quality whereas legumes and herbs are, with brassicas being of good quality if fed correctly.

During winter many stock classes can be fed at maintenance levels. Depending on the class of stock, feed quality can potentially be reduced at this time of year also.

There are over 300 cultivars of forage available to meet animal requirements at different times of the year. It is important to select a forage that is suited to your:

• Soil
• Fertility
• Climate - especially rainfall
• Stock class
• Grazing system

The cultivars are often bred and tested in rotationally grazed, high fertility systems with irrigation. Optimal crop results will result from replicating that environment as much as possible. It is likely to be more beneficial to focus on a small area and ideal conditions.

New pastures are a big investment with high input costs including fertiliser. They should be cared for to maximise grass production and pasture persistency. With good quality through pasture management, lambs can grow at 200g/d on pasture. 

On brassica crops there are typically liveweight losses for the first week. In week three onwards, liveweight gains of 300-400g/d can be seen. This proves it is better to put a smaller number of lambs on the crop for a longer period to maximise liveweight gains.

Forage crops should be used to meet the needs of the most appropriate stock class. Lamb finishing may be the most obvious choice but consider boosting ewe condition to increase conception and the subsequent lamb harvest.

Tom supplied an example where forage crops were used in a certain way on a south island hill country farm that had farmed the same way for many years. Routinely, lucerne was made into silage in spring, with the merino ewes and lambs grazing average quality pasture. The finishing lambs were fed high quality forages in autumn, increasing their carcass weights (CW) by 2kgs. 

In this situation, ewes were mated at 55kg, lambing 95%, weaning at 110d at 27kg and the mid-sale dates of lambs was in June with  a CW of 18kg.

Tom convinced the farmers to make silage from the medium quality pastures and feed the lucerne mixture to the ewes with lambs at foot (3-4 day rotation behind a hotwire). Once the lambs were gone in autumn, the ewes were fed the forage crops.

With this system, ewes were mated at 65kg, lambing 125%, weaning at 75d at 27.5kg with 80% of the lambs sold by mid-February! This clearly demonstrates the potential benefits of well-managed forage crops.

Roy Fraser, a consultant with PGG Wrightsons, demonstrated production and utilisation have a huge effect on the cost/kgDM for crops. Fodder crops move a large quantity of feed from times of high growth and low returns, to times of low growth and high returns. They need careful planning and management to maximise production and return.

To maximise farm profitability focus on increasing feed harvested/ha; reducing cost of production; improving feed conversion efficiency and increasing the net value of product sold.

Fodder crop yield and utilisation
Roy provided figures demonstrating that with a crop costing $600/ha, a yield of 5000kg DM/ha cost $0.12/kg DM compared to a yield of 10,000kg DM/ha costing $0.06/kg DM. However this cost increases when considering crop utilisation. 70% utilisation of a 5T crop means 3500kg DM/ha is harvested, increasing the cost to $0.17/kg DM. A 10T crop harvesting 7T costs $0.09/kg DM. Optimising utilisation will reduce costs.

Fodder crops have the advantage of moving a large quantity of feed from a time of year with high growth and low returns to a time with low growth and high returns.

Consider carefully what crops are best for your environment. You may need the help of an agronomist to do this. The crop needs to grow well and thrive for the investment to be worthwhile. Use a class of stock that will perform well on the crop but aim to use a class that will create good returns. The value of lambs has a large effect on the net income from crop without any alteration in liveweight gain or stocking rates.  For example, over summer, lamb prices often fall. Lambs that have been on an expensive crop may be sold at the end of the summer at a lower price than what they were bought for. However in Spring and Autumn, lamb prices often increase.

Roy explained the concepts of ‘slippage' and ‘addage'. The following table demonstrates how selling in a better market makes you more money. For a forage system to be profitable, there needs to be addage, not slippage.

Table 1. Slippage and addage with different classes of bulls  (click to enlarge)

Pugging
Pugging can reduce pasture production by more than 900kg DM/ha. At 12c/kg DM, this is $110/ha. Using a fodder crop over the wetter months can prevent pasture pugging damage. For example, an 8T DM kale crop will feed 16 R2 cattle for 60 days during winter. Fed on pasture only, they would graze and potentially damage 6.4ha. At $110/ha for the grass potentially lost, the extra $700 from feeding these animals on kale can theoretically be added to the income created from the crop.

 Feeding Hunter
Lamb liveweight gains will be optimised on a 2-3kg DM/d allowance at 60-70% utilisation. This is not a high utilisation of the crop but the residual can be utilised by another stock class. Lowering the residual will also reduce DM production.

Figure 1. Hunter residual with lamb allowance of 2.5kg DM/head/day (click to enlarge)

Monitoring fodder crops
It is worthwhile monitoring the production responses from your crops. Record the date, number and liveweight of animals going onto the crop and the date, number and liveweight when they come off the crop. This, combined with crop size, estimated yield and estimated animal intake can provide valuable information and allow comparison between crops and between years so you can make better decisions for the best options in your farming system.

 Peter Kemp is the Head of Agronomy at Massey University. He took us on a tour of several crops around Massey.

Table 2. Comparison of LWG of lambs on different forages (click image to enlarge)

Plantain will persist for four to five years if cared for. Peter recommends lax grazing to maximise lamb growth rates and is currently doing a trial to determine growth patterns of the plant when grazed to different levels. Three weeks is required between grazings and care must be taken not to create too much treading damage. There seems to be a reduced faecal egg count in animals grazing plantain. It is assumed the parasitic larvae are unable to climb the plantain leaves rather than a chemical component of the plant.

Only white clover surpasses chicory for good quality feed. White clover is harder to control whereas Chicory will last for four years and is best planted in a mix with ryegrass and white clover.  The individual chicory plants die each year but plant size increases. The gaps fill with ryegrass or clover, maintaining crop production.

It is important not to graze hard during the winter but incorporating ryegrass and clover will create a more tread-tolerant crop.  The first grazing should occur at 25-30cm and residuals should always be more than 5cm. In late October - November, the primary reproductive stem grows, and can reach up to 60cm. This can be grazed whilst it is still soft down to 10cm. 

A mixed crop of 6kg/ha Plantain, 6kg/ha Chicory, 4kg/ha Ryegrass and 4kg/ha of white clover will grow lambs at 250g/d from January to March. It has a long growing season and has the benefit of minimising tail end lambs. Because there are so many options, all lambs find a crop they like.

Bill Hare from Cheltenham has grown Lucerne for several years. This crop has a long tap root so survives well in dry conditions. With good management it will last the longest of the crops. This management is important as it has high input costs which are ideally spread over a long period. Bill found it difficult to utilise the crop well. He has made both hay and silage from it and finds the silage is a good feed for bulls in dry Autumns and is a good way to shift the growth into a time of year where the feed is needed. Feeding the silage to the bulls has better results than grazing lambs on the lucerne crop (slippage).

Paul Maguire from PGG Wrightson Seeds discussed cultivar and endophyte selection. When considering grass-seed, look at cultivars bred and trialled in New Zealand and think about whether the paddock is ready for a high performance cultivars. Most cultivars are grown in ideal conditions - fertility, moisture, grazing pattern. Aim to match this as closely as reasonably possible.

 Short term ryegrasses are annuals that last 8-12m, the Italian ryegrass lasts 18m-2yr, short rotation cultivars 3-5yrs and long rotation ryes last longer.

The heading date of a cultivar is the date when 50% of the plants have emerged seed heads (about four weeks before flowering). Nui is defined as day zero and other cultivars have heading dates between ‘Early' - heading more than 6d before Nui to ‘Very Late' - heading more than 35d after Nui. A mix of cultivars with varying heading dates can be used as a way to control pasture quality.

Compared to diploids, tetraploid cultivars are less dense but more palatable and digestible and have improved utilisation and intake which aids in facial eczema control. With good management, tetraploids have improved animal production, are more clover friendly and are visually more impressive but are less competitive with weeds and do not persist as well as diploids.

Endophytes have been incorporated into ryegrass to prevent attacks from black beetle, porina, argentine stem weevil, root aphid and grass grub. It is important to note that endophytes are not expressed until six weeks after sowing.

AR37 does not control grass grub but has good control over the other bugs. There is an associated increase of up to 20% in DM production.  It is important not to feed hay from other low or non-endophyte pastures onto that grass as the seeds drop off and introduce those plants.

When buying seed, discuss endophyte and germination. Do not store seed for long periods on-farm as the germination rate decreases with time.

 ‘White clover the forgotten resource?' was presented by John Brock. White clover is important in New Zealand pastoral agriculture as it fixes atmospheric  nitrogen (N) and improves soil fertility. Whilst doing that, it produces a high quality feed with great animal performance.

Clover requirements:

• Water - >40mm/month to survive, >60mm/month to perform
• pH >5.3
• Olsen P 15-30
• S0₄ sulphur >10
• Organic sulphur 10-20
• Light at the soil surface
• Warmth - grows best at 24° (18-30°)

As well as the above conditions clover requires a good seed bed - fine and firm, sown at 5-10mm. Do not use nitrogen fertiliser at sowing and keep ryegrass seed to around 10kg/ha (clover at 3kg/ha or 4-5kg/ha if coated). 

Clover grows in a set pattern. It begins with a rosette phase with a tap root. This lasts a year and is followed by the expansion phase, also supported by a tap root. Grazing too hard at this time of year will affect further growth.  At this stage, roots form at the nodes and branch. The taproots then begin dying and the multiple new plants are supported by their new roots. At this stage, management must change to encourage clover growth.

It takes one entire year for white clover to establish.

Once established, white clover is in the ‘clonal' form. The temperature dictates what the plant does:

• Late autumn-winter - rooting occurs, stolons buried due to rain, earthworm activity and treading damage. Slow growth
• Late winter - maximum root growth to support plants for following summer. At more than 4°C, nodules begin fixing nitrogen. Encourage growth at this time
• Early spring - the buried stolons resurface, shoot growth and branching increases. Encourage growth at this time
• Mid spring - at 9°C or higher, leaf production and stolon extension cause plant growth. Old stolons die, large plants break up into smaller plants and new branches form.
• Late spring/early summer - More branching occurs
• Mid summer/mid autumn - maximum shoot growth. Do not overgraze

Grazing management is important to ensure clover growth. The plant needs good light at the soil level to encourage branching and rooting. High covers will reduce soil light, reducing branching and rooting and will make the plant susceptible to overgrazing. The plant may look good in the sward but is likely to be weak and less persistant. Brock recommends close frequent grazing, keeping residuals at or above 1000kg DM/ha. However, in the warmer season when clover plants are explanding, rotationally graze to encourage growth. 

In a drought, clover is susceptible to ‘sunburn' and plant death as only the young forms have a taproot. To aid clover survival in the day, maintain a vegetation cover to reduce exposure to the sun.

John went on to discuss nitrogen fixation and soil nitrogen. Clover prefers to use soil nitrogen (N)  than atmospheric N as soil N is easier to uptake. Therefore, if applying urea, the clover will fix less atmospheric N. 

Grass growth utilises soil N, creating a deficit and stimulating clover to fix N. Clover must be short of soil N to do this. Remember, white clover only fixes 50-200kg N/ha/yr, not 500!

John then discussed soil carbon. Soil organic matter from decaying plant and animal material houses microbes that aid in nutrient trapping.   If the organic matter is high in C (C:N >14) e.g. in woody material (C:N >80), there will be low nutrient availability. If there is a low carbon content (C:N ~10) e.g. in grasses (C:N>30) or clover (C:N 12-15), it is easier to access these nutrients.

Decreasing the C:N ratio will increase the availability of nutrients. This can be achieved by increasing N through clover fixing N or by reducing C. However, reducing the carbon component of the soil organic matter means carbon dioxide is being lost into the atmosphere. Also, if soil C levels drop too low, there is less opportunity for the organic matter to trap nutrients that can be later be accessed.

Andrew Ellingham runs an 1170ha farm in Ormondville. He has a 160ha block in which he has been developing 10ha a year. He sows a kale/swede crop on which he finishes lambs in summer and winter lambs and grazes bulls from July until September.The bulls grow at 0.9kg/d for 60 days, and the lambs at 250g/d for the six weeks they are on the crop. These stock are growing 20% faster than their counterparts on grass.

The grass that follows grows significantly more than the old grass. At four years old, the new grass grows 12.5T DM/ha compared to 8.75T DM/ha. The old grass is producing 30% less. 

With good planning, management and tailoring the system to fit supply and demand, this development is adding significant value to this farm.

The day ended with a BBQ and some light refreshments and we all went home with a lot to think about! If you have any suggestions for topics you would like covered or how we could improve these days, please contact Greta.