Northern Irrigation and Southern Riverina
"Strength does not come from physical capacity. It comes from an indomitable will." Mahatma Gandhi
Inside this issue:
- New era dawns in dairy animal genomics
- A tight calving pattern starts with heifers
- Lead your dairy business to success
- Speeding up genetic gain
- Monthly reminders
- What's On
Grazing Management - The forgotten factor with N fertiliser?
Dr. Martin Staines and Richard Morris, Department of Agriculture and Food, Western Australia.
There is still much reluctance among farmers and advisors to accept the compelling evidence that grazing of ryegrass pastures by leaf stage (LS) should be the determining factor in setting grazing interval.
Work by Bill Fulkerson, Danny Donaghy and others has shown that ryegrass pasture growth rates (PGR) and total pasture production per year are maximised and pasture quality optimised if ryegrass pastures are allowed to reach the three leaf stage. Put simply, the three live leaves per ryegrass tiller each take the same time to develop but get progressively bigger. For ryegrass grown to three leaves, the first leaf contributes 15-20 per cent of total pasture biomass, the second leaf 30-35 per cent and the third leaf 45-50 per cent. There is little difference in ME content between the first and third leaf.
Research by Martin Staines, Richard Morris and colleagues as part of the Greener Pastures project at the Vasse Research Centre in Western Australia provides further insight into the intricacies of grazing by leaf stage, and in particular the impact of fertiliser nitrogen (N).
The Greener Pastures research team suggest that increased use of N fertiliser on Australian dairy farms frequently results in farmers reducing grazing interval by increasing rotation speeds to manage the higher pasture biomass and/or canopy closure associated with higher pasture growth rates. The Greener Pastures latest work shows that the increase in rotation speed cancels out part of the potential pasture growth response from N fertiliser, and impacts adversely on the nutritional balance of pasture for dairy cows.
From January to May 2007 a cutting trial was conducted with irrigated perennial ryegrass to investigate what happens when different cutting intervals (rotation speed) were combined with different N fertiliser rates. The trial consisted of six treatments; with ryegrass defoliated (cut to 5 cm above ground level) when tillers had grown either 1½ or 2 or 2½ leaves. This resulted in ten, seven and five cuts respectively over the 20 week trial, or mean rotation speeds of 14, 19 and 26 days.
Ryegrass at each leaf stage treatment received N fertiliser after each cut in amounts equivalent to 1 or 2 kg/ha/day. At each cut, the amount of harvested pasture was recorded and analysed for quality, particularly metabolisable energy, crude protein and sugar (water soluble carbohydrates). At the end of 20 weeks, root dry matter (DM) was determined.
The mean pasture growth rate (PGR over 20 weeks) for the six treatments ranged from 48 to 95 kg DM/ha/day (see table 1).
With defoliation at 2½ leaves, an increase of fertiliser N from 1 to 2 kg/ha/d increased PGR from 61 to 95 kg DM/ha/day, which is an extraordinary response of 34 kg DM/kg N.
Table 1: How cutting interval (leaf stage) and N fertiliser rate influenced PGR (kg DM/ha/day) of perennial ryegrass.
|Leaf Stage||Plant Growth Rate kg DM/ha/day||PGR Response kg DM/day/kg N|
With defoliation at two leaves, an increase of fertiliser N from 1 to 2 kg/ha/day increased PGR 29 kg DM/kg N (78 - 49 kg DM/ha/d). With defoliation at 1½ leaves, an increase of fertiliser N from 1 to 2 kg/ha/day increased PGR 23 kg DM/kg N from (71 - 48 to kg DM/ha/day).
Let's go back to 2½ leaves. Think of a paddock grazed at 2½ leaves, where N fertiliser is increased from 1 kg to 2 kg/ha/day. Mean PGR increased from 61 to 95 kg DM/ha/day or by 56 per cent, provided that grazing is maintained at 2½ leaves (Table 2).
Table 2: How the PGR response of perennial ryegrass to N fertiliser is influenced by leaf stage (kg DM/ha/day).
If, due to increased PGR, the rotation speed in increased and the paddock is grazed earlier, say at two leaves, the mean PGR achieved is 78 kg DM/ha/day, not 95 kg DM/ha/day. This has reduced the PGR response to the extra kg of N fertiliser (per ha per day) from 34 to 17 kg DM/kg N.
If the paddock is grazed earlier still, at 1½ leaves, the mean PGR achieved is 71 kg DM/ha/day, instead of 95 kg DM/ha/day. This has reduced the PGR response from 34 to 10 kg DM/kg N.
Most of us would think little of it as 10 kg DM/kg N seems quite acceptable. But we could have had a response of 34 kg DM/day/kg N if rotation had not been altered.
Consider the irony of this situation? We apply extra fertiliser N with the primary goal of increasing PGR. Then in response to the increased PGR we shorten our rotation so that we graze at two leaves per ryegrass tiller, or even earlier. This suppresses PGR because it does not let the ryegrass plant develop its biggest (third) leaf. We've incurred the cost of extra N fertiliser to increase PGR but then suppress the PGR potential through earlier grazing.
The argument against grazing at the 1½ - 2 leaf stage does not end here. The nutritional balance of ryegrass at 1½ -2 leaves is much less suited to the dairy cow than ryegrass with 2½ (or 3) leaves. The difference is not in ME content, but in protein content and sugar content (see Table 3) which is important for rumen health and cow health. The optimum protein to sugar ratio for rumen bugs on a diet of high-quality pasture is about 1.1. In ryegrass with 1½ leaves this ratio was found to be 1.7 in our trial, mainly due to low levels of sugar in ryegrass. The ratio dropped to the ideal of 1 to 1.2 when pastures developed 2 or 2½ leaves.
Pastures grazed at 1½ leaves had insufficient fermentable sugars to allow rumen microbes to use the high pasture protein levels. This excess protein is converted to ammonia in the rumen which then needs to be converted to urea and excreted in urine. This metabolic process requires energy, which reduces production and/or body condition and may also negatively affect fertility.
Table 3: How cutting interval (leaf stage) influenced protein and sugar content of perennial ryegrass.
|Leaf stage at grazing|
|1½ LS||2 LS||2½ LS|
|Pasture protein %||16||15||13|
|Pasture sugar %||10||12||14|
|Protein: sugar ratio||1.6||1.2||1.1|
Another finding of the Greener Pastures study was that ryegrass cut at 2½ leaves over 20 weeks had a greater root mass and higher number of tillers per m² of sward at the end of the trial than ryegrass cut at 1½ leaves during that time. This explains the observation that pastures that are consistently grazed at the 2½ - 3-leaf stage, rather than the 1½ - 2-leaf stage, with regular N applications respond better to irrigation / rainfall and are generally more vigorous when conditions for growth are less than ideal.
Our results lead us to the following suggestions on grazing management and N fertiliser use:
- Pasture quality and quantity for grazing by dairy cows is optimized by grazing at 2 ½ - 3 leaves.
- Only graze ryegrass earlier than 3 leaves per tiller if pasture is being wasted. Try not to graze earlier than 2½ leaves.
- Fast rotations (grazing at 1½ or 2 ryegrass leaves) can be expected to result in considerably less pasture being produced compared to slower rotations (grazing at 2½ to 3 ryegrass leaves)
- Fast rotations (grazing at 1½ or 2 ryegrass leaves) result in pasture that is poorly balanced to the needs of the dairy cow, with excess protein but low sugar levels. High urea (N) losses in urine can result in pasture scalding and have an adverse environmental impact.
- If canopy closure is consistently occurring before 2½ leaves, the first response should be to reduce the amount of N fertiliser applied, rather than to speed up your rotation.
We are currently repeating our cutting trial, but this time with defoliation of perennial ryegrass at 2 or 2½ or 3 leaves, and with N fertiliser applied at 1, 2 or 3 kg N/ha/day.
In addition, we are now applying our findings to the grazing management and N fertiliser use of our Greener Pastures Innovation herd of 120 cows. This is large enough to represent a commercial dairy farm where we can further fine tune rotational grazing management and N fertiliser use in closely monitored, yet 'real world' conditions.
New era dawns in dairy animal genomics
The Australian dairy industry has entered a new genomic era in which dairy farmers are now able to make breeding decisions with confidence on genomic data alone.
After two years of intensive research work at the Dairy Futures Cooperative Research Centre (CRC), genomic profiling of 10,000 dairy cattle has achieved levels of reliability that make much more accurate predictions of how good a bull's or a heifer's genetics are for milk production, fertility and other traits that affect profitability.
On average the reliability of genomic breeding values for young bulls (with no daughters) is now equivalent to a bull proof with 30 milking daughters. The potential economic value of this new technology is estimated at $100 million over the next 12 years.
"This new level of genomic reliability for key traits confirms the creation of a viable, new market sector – genomically tested bulls with high levels of reliability under Australian dairy farming conditions," Dairy Futures CRC Chief Executive David Nation said.
In this new era, making breeding decisions with confidence on genomic information alone is set to become standard practice among dairy farmers, who stand to double the genetic gain in their herds; bringing forward the introduction of elite genetics by several generations and producing higher performing dairy cows earlier.
Based on overseas experience with genomics, the speed and scale of the uptake of this new technology is expected to be rapid. (In Ireland, less than two years after achieving similar levels of genomic reliability, 50 per cent of bulls used in dairy breeding programs are now young genomic bulls.)
Professional breeders who market bulls here and overseas will be able to test a range of high performing bulls at a young age; potentially making these bulls more marketable and adding diversity to the sires available for breeding.
Dairy farmers purchasing natural sires will have access to a broader market of bulls that have been genomically tested.
Environmental factors and farming practices, which vary from country to country, have a critical impact on the performance of imported sires. Bull companies, the majority of which import semen from sires proven under US, Canadian, UK or European conditions, can now have their bulls genomically tested for performance under Australian conditions. The results can be provided quickly to assist them in deciding which bulls to market in Australia and give them an edge in their marketing programs.
The technology will give Australian dairy farmers, who already look globally for suitable international sires, greater confidence in selecting bulls that have been genomically tested for Australian conditions.
Genomics also present the industry with an opportunity to test for 'outliers'; those animals that may have been overlooked previously but whose superior traits can now be identified through a simple DNA test.
For young dairy farmers entering the industry genomics presents an opportunity to build a quality herd rapidly, making dramatic improvements in performance by choosing elite young bulls on their genomic test alone.
For more information visit www.dairyfuturescrc.com.au.
A tight calving pattern starts with heifers
Dairy farmers who want to achieve and maintain a tight calving pattern need to include heifers in the plan.
Dr Barry Zimmermann, who manages Dairy Australia's InCalf program, said that heifer management had a big impact on a herd's calving pattern.
"Decisions you make about heifer management will strongly affect the herd's calving pattern," Dr Zimmermann said.
"For example the calving pattern of your heifers is strongly influenced by their growth rates and their weight at joining. Secondly, the herds calving pattern will be influenced by the number of heifers available to replace older and less fertile cows – as they will calve later if they remain in the herd."
A tight calving pattern is achieved by maximizing the number of cows and heifers that calve in the first three weeks of the calving period. Aim to have at least 85 per cent of your heifers calved by week three.
"A good strategy is to join heifers to start calving two weeks before the main herd. This gives them some extra time to recover from their first calving and start cycling before the joining period.
"It also compensates for lower conception rates that can be experienced by using sexed semen," he said.
But joining heifers early relies on excellent calf and heifer rearing practices so that heifers reach their target joining weight by 14 months, or as early as 13 months for later born calves.
"To achieve target growth rates, heifers will need a high-quality supplement at some times, for example post weaning and when high quality pasture is not available."
Supplements should contain at least 11-5 11.5 mega joules metabolisable energy per kilogram of dry matter, and 16 per cent crude protein.
The best way to be sure heifers will achieve their target joining weight by 14 months is to weigh them regularly and take action if target growth rates are not achieved.
If heifers reach their target mating weight by 14 months, it may be worth considering a synchronization/blanket AI program.
This has two benefits. Firstly it means a large number of the heifers will calve early, setting the herd up for a tight calving pattern. Secondly by inseminating the heifers, their progeny can be kept as replacement stock, so this will boost the number of replacement heifers available in two years time.
For more information refer to Heifers: Big Girls XL, available at www.dairyaustralia.com.au/incalf.
InCalf is an example of your levy at work.
Lead your dairy business to success
"I now understand where people and organisations fit in the dairy industry. I also feel better equipped to build my network, have my say and hopefully influence things positively for our dairy business". Shane McMillan, 2011 'Lead and Manage' course participant.
The dairy industry has faced its fair share of challenges and dairy farmers have always stepped up to tackle them head on.
In the current operating environment, now is the time to get involved and help lead your dairy business and the wider industry through the issues currently confronting us.
The prospects to make a difference for you and your community are unlimited. There is a need for capable people to get involved in established industry groups, such as the Murray Dairy Board and Regional Education and extension committee, to help drive a successful and productive future for us all. In response to this need the NCDEA has developed a program to give you the skills and confidence to help shape the future of the dairy industry.
The RTE 6802A Lead and manage industry and community groups program offers a fascinating insight into the world of leadership, establishing networks and setting a successful direction for community and industry organisations for the benefit of all.
Lead and manage industry and community groups is your chance to understand the industry that your dairy business operates in, your role in it and the opportunity you have to influence things for the improvement of your industry and your business.
Learn about corporate governance, the structure of organisations, roles and responsibilities within an organisation, business ethics and the importance of protocols and procedures.
Topics covered include:
- Developing essential skills such as personal skills, establishing codes of behaviour, leadership skills, team skills and conflict resolution skills.
- Which leadership style works best for you in different business, community and industry settings.
- Developing tools to help you build effective teams in your business, community or industry organisation.
- How to apply strategic planning principles and take the 'Helicopter view' of your organisation.
- Designing and implementing appropriate communication strategies.
- Understanding your natural tendencies and personality type.
- Growing your professional and business relationships.
- Understanding negotiation, goal setting, emotional intelligence and conflict resolution.
The program begins on Tuesday, 4 September 10am to 3pm, and continues on Tuesday 23, 30 October and 13 November.
It will be delivered from Warragul, Shepparton (William Orr campus) and Terang, Victoria.
The program costs approximately $300 after a Dairy Australia subsidy. This includes four days attendance and course materials.
To enrol or find out more information please contact Jasbir Singh, telephone (03) 5833 2855, visit www.ncdea.edu.au.
The NCDEA is the dairy industry's own provider of education and training
Speeding up genetic gain
Dairy farmers who want to speed up the rate of genetic gain in their herds should consider inseminating their maiden heifers.
Michelle Axford from the Australian Dairy Herd Improvement Scheme said inseminating maiden heifers helps in two ways.
"Firstly it increases the number of replacement calves available, and that allows more opportunity for culling," said Mrs Axford.
"Secondly, it reduces the generation interval, that is the number of years between mother and progeny. Heifers represent the most modern genetics in the herd, and their progeny are available a year earlier if they are inseminated and their calves kept as replacements."
However inseminating maiden heifers relies on excellent calf rearing and heifer nutrition so that they achieve their target mating weight by 14 months of age, or even younger for later born calves.
"Inseminating maiden heifers is a good strategy for speeding up genetic gain, but it may involve planning ahead to improve heifer growth rates," she said.
Think ahead with straw numbers
Another important step to fast tracking genetic gain is to ensure enough quality replacement heifers are reared, and that starts with the number of AI straws ordered.
"Most people think in terms of 'how many straws do I order?' but the more important question is 'how many replacements do I need in three years time?'," she said.
Mrs Axford recommends farmers look three years ahead and decide how many replacement heifers they'll need entering the herd.
"The number should include any extra heifers to expand the herd size or for sale or export," she said.
"Then it's just a simple rule of thumb – allow six straws for every replacement heifer," she said.
"If you use some of those straws over maiden heifers you'll not only have enough replacements, you'll have the added benefits of speeding up genetic gain and having a larger pool of early-born calves to keep as replacements," Mrs Axford said.
The ADHIS website has a simple calculator tool that allows the user to change the percentage rates of the various allowances for their herd.
For more information contact Michelle Axford, ADHIS Extension and Education Manager, telephone 0427 573 330, email email@example.com or visit www.adhis.com.au.
ADHIS is an initiative of Australian Dairy Farmers', that receives the majority of its funding from Dairy Australia through the Dairy Services Levy.
Don't take your eye off the ball with grazing management. Make sure a residual of 4-6 centimetres is being maintained and that the rotation matches pasture growth rates.
Consider the use of nitrogen to boost early pasture growth. The response will take about four to six weeks.
Think about spring sowing options for pastures that have failed to establish. Are you missing out on valuable fodder production from those paddocks?
Monitor cows closely prior to and post calving and maintain good cow nutrition to avoid milk fever and other metabolic diseases.
How are the yearlings going? They're still a couple of months off joining. A timely drench and a diet that meets their requirements will help to keep them growing.
Ensure calves for slaughter are not treated with antibiotics or fed milk containing antibiotic residues. If it does happen, observe withholding periods.
Cash flow and equity position will be the biggest drivers of decisions at the moment. Do you have a good understanding of your business' financial position? Get someone to help you work through these issues.
Consider all members of the family during these busy times. Make time to talk about other issues besides which cows are calving or which paddock they are going into.
Manage the Production System
Beginning Tuesday 11 September and continuing for five weeks, 10am - 3pm, Shepparton.
Plan and Manage Infrastructure Requirements
Wednesday 12 September, 10am - 3pm, Shepparton.
Cups On / Cups Off
Monday 27 August 9.30am - 2.30pm and Tuesday 28 August 9.30am - 12.30pm, DEPI Tatura
Monday 10 September 9.30am - 2.30pm and Tuesday 11 September 9.30am - 12.30pm, Rochester Golf Club
Rear Newborn Calves
12 and 19 September 10am - 3pm, DEPI Tatura
Follow OHS Procedures
17 September 10am - 3pm, Yarrawalla
Manage Farm Safety
Friday 14 and 21 August 10am - 3pm, Numurkah
23 August 9am - 4pm, Yarrawalla
For more information please visit www.ncdea.edu.au or 1300 0 NCDEA
Young Dairy Network
Would you like to join a Young Dairy Business Network? If so, please contact the YDN Coordinator, Geraldine Torpy.
The YDN is seeking expressions of interest for People GPS courses. Once we have the numbers, we can get one up and running in your area ASAP – so please register your interest with Geraldine Torpy, telephone 0409 577 317, or email firstname.lastname@example.org.
Any feedback or comments are welcomed by the editor Leah de Vries (03) 5833 5223.
For previous issues of the Dairy Bulletin please go to our website www.depi.vic.gov.au/agriculture-and-food/dairy.