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The Dairy Bulletin - February 2012
Inside this issue:
- How flexible is lucerne?
- Monthly reminders
- What’s On
HOW MUCH PERENNIAL RYEGRASS DO I SOW?
Tom Farran, DPI Tatura
To make the most of the improvement in seasonal conditions and increased water availability many farmers have begun tinkering with their systems, moving away from farming for the drier years. At the forefront of people’s minds however, are the memories of the drought and the high cost of perennial pasture over summer if they didn’t have a relatively cheap water source.
This means a return to the days of wall to wall ‘summer’ pasture is considered too risky and would leave the farm exposed to the risk of dry years. Also, many other aspects are likely to have changed, such as calving patterns and stocking rate, which may mean the farm is no longer suited to nearly all perennial pastures.
These factors mean many farmers are now trying to decide how big an area of the farm should be sown down to perennial ryegrass. Unfortunately there isn’t a “one size fits all” answer to this question as every farm system is different and has a different set of resources and attitude to risk. This article will look at some of the key considerations to help provide some of the information needed to make the best decision possible.
How will having more perennial ryegrass change feed supply?
Perennial ryegrass is generally assumed to have slower growth in the first autumn and winter compared to annual and Italian ryegrass. However, many of the newer varieties of perennial ryegrass appear to perform nearly as well as the annual rye grasses through this period. Annuals and Italians will often produce more dry matter through the early to mid spring period, which often results in needing to conserve more of the surplus earlier in the spring when the risk of difficult conservation conditions may be higher.
From late spring to mid autumn the perennials will out-compete the annuals and Italian ryegrasses in yield as long as adequate moisture is present. Any slower growth over the autumn and winter has normally been recouped by late spring.
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To limit the cost of production it is desirable for forages to have a fairly consistent supply of feed each month. This would avoid having the high costs involved in conserving surplus feed and feeding it back at times when the herd’s needs are greater than the forages growth rate.
For this reason it is desirable to choose forages that provide the most consistent supply of feed, or to use a mix of different forages that complement each other by keeping the feed supply relatively consistent throughout the year.
Figure 1 demonstrates how much the various forages grow on average per day (measured in kilograms of dry matter (DM) per day per hectare) based on research done at Kyabram in 2005 and 2006. The graph shows perennial ryegrass provides the most consistent feed throughout the year.
All of the annual options grow faster during their peak period but also rapidly drop off as they come to the end of their cycle. Even if a winter annual was matched with a summer annual (e.g. oats and millet) there is still a period in late spring/ early summer and autumn when there is very little feed being grown during the changeover period.
Traditionally, many farms in Victoria’s northern irrigation region consisted mostly perennial pastures combined with a spring (August and September) calving herd. This calving time best matched when the cows needed feed to when the feed was growing. Many farms have changed to have at least a proportion of the herd now calving in the autumn (March and April). This means the autumn calving cows now require more feed during the winter months and less feed in late summer.
Figure 2 shows how the feed demands of a farm change if the calving pattern is altered. This graph is based on the same herd stocked at three cows per hectare consuming the same total amount of feed for the year. The biggest change is during the winter period when the spring cows are dried off and during the late summer/early autumn when the autumn cows are dried off. When compared with the first graph, it demonstrates that a purely perennial ryegrass-based farm does not match the feed demand of an autumn calving herd very well. It also shows that an annual ryegrass -based farm doesn’t match the feed supply of a spring calving herd.
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How much water is required to irrigate perennial ryegrass and what is its water use efficiency?
There is a big variance in the amount of water required from farm to farm, paddock to paddock and year to year. Many farms only needed around 3-4 megalitres per hectare to irrigate perennial pastures in the 2010/11 season. Yet the same farm needed around 12 megalitres per hectare in the 2006/07 season. Most farms use on average about 8-12 megalitres per hectare, depending on soil type, climate and irrigation layout.
The results in Table 1 (page 4) show the big influence seasonal conditions have on water use. The 2005 season had considerably more rainfall than the 2006 season. This had a large influence on the amount of irrigation water required.
The water use efficiency (WUE) in Table 1 only takes into account irrigation water used (not accounting for rainfall), and is a calculated by dividing the total amount of irrigation water grown by the total tonnes of dry matter harvested. The WUE between the two years varied a lot for all species, mostly due to rainfall reducing the need for irrigation. This table demonstrates that the crops that required irrigation over the summer period had a reduced WUE regardless of the species.
What effect does putting in more perennial ryegrass have on total feed costs?
Three big factors influence the total feed cost when comparing different species of forages; conservation costs, establishment costs and water price.
While it will often cost about the same amount per tonne to conserve different species on the same farm, conservation costs are important because some species require conservation of a greater percentage of the total amount produced.
For example, in Table 1 the perennial ryegrass/ white clover mix and the Persian clover/Italian ryegrass mix produced a similar amount of feed. However, due to Persian clover/Italian ryegrass mix’s shorter growing period, a much larger proportion of the feed would need to be conserved. This greatly increases the total conservation costs (including feeding back).
Establishment costs include the cost of the seed, cost of sowing and any chemical and cultivation costs associated with establishing a crop. For annual species this cost is incurred every year.
| Forage treatment | Forage removed (t DM/ha) | Irrigation water applied (ML) | Irrigation WUE (t DM/ML) | |||
|---|---|---|---|---|---|---|
| 2005 | 2006 | 2005 | 2006 | 2005 | 2006 | |
| Perennial ryegrass / white clover | 16.6 | 13.4 | 8.1 | 12.0 | 2.1 | 1.1 |
| Tall fescue / white clover | 17.6 | 17.8 | 8.4 | 12.0 | 2.1 | 1.5 |
| Lucerne | 17.1 | 19.3 | 6.5 | 10.4 | 2.6 | 1.9 |
| Persian clover / Italian ryegrass | 16.0 | 12.3 | 4.4 | 7.1 | 3.6 | 1.7 |
| Sub clover / Italian rye grass | 10.1 | 9.4 | 3.3 | 4.4 | 3.0 | 2.1 |
| Double crop (oats / millet) - Total | 18.3 | 18.1 | 7.4 | 11.1 | 2.5 | 1.6 |
For a double crop (winter crop and then a summer crop) this cost is incurred twice a year and for a perennial it is only incurred every few years.
In the case of perennial ryegrass it is reasonable to expect to have to oversow every 3-5 years. In most cases the cost to establish the perennial ryegrass will be higher than annuals as the seed is more expensive. However, this cost is only incurred every 3-5 years and not every year.
The cost of water becomes very important the more expensive it gets. When water is cheap the conservation and establishment costs become more important. The more expensive water becomes the more important WUE becomes. Let’s look at the costs if water was valued at $300 per megalitre. If you had WUE of two tonne dry matter per megalitre for annual ryegrass and one tonne dry matter per megalitre for perennial ryegrass, it costs $150 per tonne of dry matter to grow annual ryegrass and $300 per tonne of dry matter for perennial ryegrass in water costs alone. For many farmers, this $150 per tonne difference would be greater than the costs involved in conserving a tonne of feed. However, when water is expensive most forage options become unprofitable in the long term.
There isn’t going to be one right answer for everybody but you can follow the logic above to narrow down the options for your farm. Some farmers will jump at the opportunity to return to growing more perennial pasture to simplify their system, and others will be happy with a mix. No matter what option you choose this autumn, the most important thing is to make sure you manage it well.
The Feeding Pastures for Profit program (FPFP) is being offered again this year and it will be a great opportunity to re-visit the essential skills required to get grazing and feeding right for your farm. Some farmers may wish to learn and share new ideas with a group of peers in a friendly, on-farm environment, and others may wish to re-visit the program to kick-start their recovery from drought. Whatever the reason please take the time to find out what FPFP can do for your business.
For more information contact Tom Farran, DPI Tatura, telephone (03) 5833 5297.
HOW FLEXIBLE IS LUCERNE?
Tom Farran and Alister Lawson, DPI Tatura
return to full water allocation has been welcomed. A lot has changed to the way dairy farms are managed over the last several years. Many farmers believe that growing and consuming home grown feed using cheap water is the most profitable way forward.
They are also aware that it is only a matter of time before a low water allocation year(s) strikes again. If their business is set up based on making the most of cheap water, then a low water allocation year will likely put a huge strain on the business.
With this in mind, many farmers are trying to design their farms to be able to make the most of cheap water whilst also being prepared for low water allocation years. One option considered to achieve this dual purpose is lucerne.
Lucerne is a deep-rooted, perennial legume plant that has high nutritional quality. It has the ability to send its roots deep into the soil to access moisture from much further into the subsoil than most of the more traditional pastures grown such as ryegrass.
This enables it to survive dry periods much better than ryegrass, with a reduced chance of it needing to be re-sown the following year. Over time the stand will eventually thin out to the point that it will no longer be viable to irrigate. A lucerne stand will also thin out if it isn’t irrigated for a long time.
Is lucerne suitable for my farm?
Farmers must have suitable paddocks and be able to manage the lucerne stand. Research should be conducted into what soil types, fertility, drainage, management, etc are needed. Lucerne is relatively slow and expensive to establish and is less forgiving than options such as ryegrass.
Unless the conditions are suitable and the lucerne is managed well it could be a costly failure.
How well does lucerne survive not being irrigated? What happens to its density and growth in subsequent years?
This issue is being researched at DPI Tatura, where dry matter production, water use and plant survival are being measured over five years. The experimental treatments range from being fully irrigated for the entire season in each year, no irrigation for either one, two or three years and no irrigation in either autumn, or summer and autumn for three years. All treatments will be fully irrigated in the fifth year.
To date, the two irrigation seasons thus far have been completely different. The first year (2009/10) saw close to average rainfall and large treatment differences in irrigation water used (0.9 to 9.6 ML/ha) and dry matter production (5.0 to 15.5 t DM/ha).
Rainfall during the irrigation season in the second year (2010/11) was the highest on record (766 mm) and resulted in little difference in either total water use (10.8 v 12.8 ML/ha) or dry matter production (12.1 v 13.1 t DM/ha) between the treatments receiving the least and most irrigation water.
Consequently, drying off for a period has had no effect on the subsequent yield once irrigation has recommenced due to the uncharacteristically wet summer.
The research team anticipates that after a period of no irrigation, the lucerne stand will thin out faster than if it had been irrigated. If the density decline is small there may be no yield loss as the remaining plants may compensate through an increase in size.
However, if the density decline is large there may be a yield loss as the remaining plants will be unable to compensate.
Knowing the impact a range of irrigation scenarios has on the decline in density and subsequent effects on yield will be one of the research’s key findings.
How does lucerne compare in terms of production, water use efficiency (WUE) and quality?
The dry matter production, water use and WUE of lucerne is comparable to that of well managed perennial pastures grown at Kyabram. This was particularly evident in 2005 (a typical year) while in 2006 (a drought year) the dry matter production of lucerne was 20 per cent higher than that of the perennial ryegrass-based pasture (see Table 1 in previous article).
In terms of quality, lucerne’s energy content was 1-2 megajoules per kilogram of dry matter lower than that of the perennial ryegrass-based pasture, however, the crude protein content was 1-6 per cent dry matter units higher (Figure 3).
How does lucerne change the growth pattern and what does this mean in terms of feeding the cows?
Lucerne is a summer active perennial. This means that most of its growth is in the spring, summer and autumn with very little growth over the winter. This growth pattern is a good match for the feed demands of spring calving cows but is a poor match for autumn calving cows. Lucerne will grow a lot of feed during the time autumn cows are dried off and it will produce very little feed during the winter period when the autumn cows are in their peak feed demand period.
Figure 4 gives a demonstration of the different growth patterns of lucerne (winter activity rating of 7) and perennial ryegrass over the course of a year. The graph also shows how a farm’s feed demand changes with different calving patterns (the farm has a stocking rate of three cows per hectare).
This example has a 100 per cent spring calving herd, a 100 per cent autumn calving herd. The graph demonstrates that by changing the species grown or calving patterns, the size of the gaps between the amounts of feed grown versus the demand for feed is altered dramatically.
If a farm’s conditions are suitable then lucerne may provide benefits that more traditional options such as perennial ryegrass can’t.
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However it won’t be the ‘silver bullet’ many are hoping to find. While lucerne can survive periods without irrigation, it will thin out eventually. If this happens it becomes an expensive and time consuming process to re-establish a productive lucerne stand.
Consideration needs to be given to the effect establishing lucerne will have on the rest of the farm system. For example, with a farm that is predominately autumn calving, issues may arise around having too much feed on the farm during the late summer and not enough feed to graze during winter. If the decision is made to establish lucerne it is very important to manage it well. It requires thorough planning and preparation and is unforgiving to poor management.
See What’s On (below) for details of field days exploring this topic in more detail.
TICKLERS
A sloth calls the police to report that he was attacked and robbed by a gang of turtles. When the police ask him to describe the attack, he replies: “I.....Doooon’t.....knoooow… It... all... happened..... soooooo ... fasssst.....”
Q: what do ducks eat? A: quackers
Two Lions are eating a clown… and then one lion says to the other… “This tastes funny”.
Monthly Reminders
Stock
- Use strategies to keep the cows cool while the weather is hot so that there are no set backs (in both the cows and the young stock).
- Make sure stock have plenty of access to clean, cool water. On a hot day, a lactating cow can drink anywhere up to 150–200L/day.
- Check that the diet is meeting the requirements of stock. There are a number of indicators that can signal the need to check the balance of the diet.
- Check for pink eye.
- Make sure immunisations are up to date and stock are drenched if required.
Pasture
- It is about time to start thinking about the areas that will be sown down in the autumn, and whether this will be done with irrigation or with the autumn break.
- Start getting organised for autumn fertiliser applications by working out what you need and ordering it so it’ll be on hand when you need it.
Business
- Plan to learn something new this season. Participate in one of the upcoming courses, field days or farm walks on around the region this month.
- Take a break, even if it’s just for a couple of days. Plan it, and even send a deposit so that you are locked into going.
Safety Messages
- Remember to carry the fire extinguisher on the tractor – you never know when you will need it.
- Don’t exceed the lifting capacity of your frontend loader – some of the large square bales around are much heavier than bales you may be used to.
What’s On?
Dairy Business Expo
Find out the latest northern irrigation dairy industry facts and figures and how to interpret them from both the dairy farm monitor project and dairy directions project.
Tuesday 28 February Wilf Cox Centre in Kyabram, 10am - 2pm.
For more information, please contact Tom Farran, DPI Tatura, telephone (03) 5833 5297.
How Flexible is Lucerne?
DPI Dairy Services are running a series of field days to explore how flexible lucerne is under irrigation on dairy farms. The days will answer the following types of questions:
- Is lucerne the best option for my farm?
- How much production could I expect from lucerne?
- How water use efficient is lucerne?
- What happens to lucerne if I don’t irrigate it for a year or two?
The field day will incorporate the interim results from a research trial on flexible irrigation of lucerne currently being conducted at DPI Tatura.
Dates:
Tatura DPI - Tuesday 6th March Cohuna Bowls Club - Wednesday 7th March Katunga Recreation Reserve - Thursday 8th March Time: 11am - 1pm
For more information or to RSVP, please contact Tom Farran DPI Tatura, telephone (03) 5833 5297.
Focus Farm Field Day
Phillips family farm—Naring Thursday 16 February, 11am—1.30pm 554 Mills Road Naringaningalook Lunch provided, please RSVP to Murray Dairy, telephone (03) 5833 5312 or email admin@murraydairy.com.au.
