New Zealand’s dairy farming competitive advantage comes from the ability to grow and utilise pasture and convert this profitably into milk. Why are you in business? If you want to make a profit to grow your business, repay debt or deliver your desired lifestyle, then you will want to use the cheapest source of feed. For NZ farmers this is pasture.
Key decisions for pasture-rich dairy systems begin in February, as autumn-grown pasture needs to be rolled forward to fill the early spring deficit, to ensure sufficient pasture is available to minimise the use of supplements.
Supplements are used strategically in autumn to help gain cow condition and increase pasture cover. Systems are kept as simple as possible which allows for efficient management.
The principles outlined by leading dairy scientist Dr Arnold Bryant in the 1980s are still relevant today:
• stocking rate – matched with pasture growth rate
• calving spread – date and rate
• genetic quality of cows – pasture eaten by cows of good genetic quality
• grazing management – ensure optimum allocation and quality of pasture.
To maximise pasture growth and utilisation:
• Match the stocking rate to the average pasture growth curve over the best six-month growth period
• Plan to fill any feed gaps with the cheapest feed source available – pasture
• Autumn-grown pasture is rolled forward to fill the early spring feed gap and minimise the need for spring supplementation
• Cows must be calved in good condition (every cow at BCS 5 and heifers and second calvers at 5.5) – they will mobilise half to one condition score soon after calving
• Condensed calving patterns ensure cows reach peak intake by balance date, when pasture growth equals herd demand
• Strict use of a spring rotation planner ensures feed is allocated carefully during early spring.
This system plans to manage early spring without making or bringing in supplements. However, if pasture growth is dramatically reduced then supplements might be needed.
Autumn management is the key to providing appropriate pasture cover in spring. Timely drying off and removal of culls helps reduce demand going into early autumn and, along with an application of nitrogen, makes the most of the early autumn growth rates to push feed forward from autumn to early spring.
Lengthening the round also works in favour of growing more pasture. Research shows more pasture is grown on longer rather than shorter rotations, eg. 40 days rather than 20, in autumn. Pasture quality is maintained through the whole season, because of high pasture utilisation and grazing to tight residuals, eg 1500kg drymatter (DM)/ha).
Let’s look at some of the principles in more detail:
Use pasture first – match the feed supply and feed demand curve to determine stocking rate
Calculate the average pasture growth rate over the best six-month period of pasture growth. Then divide that by the daily cow demand:
Calculations need to be tailored for each system and farming region. A farm used only as a milking platform would have different requirements from a farm wintering-on, where silage might be needed to manage winter demand.
Be aware of the environmental and nutrient management considerations in your region when considering farm management changes. Stocking rate changes are best modelled with Overseer to assess environmental impacts.
Early autumn management
Even with the right stocking rate, there will be feed gaps to fill as cost effectively as possible. In a pasture-rich dairy system the early spring gap is filled by using long autumn and winter rotations to push autumn and winter growth through to spring. The objective is to make the most of the early autumn growth rates to grow feed that can be carried forward. Nitrogen use boosts this growth.
In addition, autumn pasture demand is reduced by culling low-producing cows and strategic use of silage – about 3-4kg DM/cow.
Supplementary feed use is targeted for this time. This strategy allows feed cover to build rapidly and produces body condition gain. Long autumn and winter rotations roll the feed forward to provide spring cover. Building an early autumn wedge means cows can be milked longer into autumn.
Base drying-off decisions on cow condition and feed cover targets.
Calculate average pasture covers required
Average pasture targets must be set and achieved at critical points from autumn through to ‘balance date’.
The following example is for an irrigated South Canterbury farm, stocked at 3.6 crossbred cows a hectare, with winter growth rates of 5kg DM/day and cows wintered off. These targets must be calculated and tailored for every farm, as they depend on stocking rate, wintering system, whether heifers are grazed on or off farm, etc.
Example target feed covers from autumn to balance day, on a South Canterbury irrigated farm with cows wintered off
• Pasture cover required on balance date – see DairyNZ Farm Fact 1.84 2000kg DM/ha
• Pasture cover needed at start of calving using all grass 2400kg DM/ha
• Pasture cover to go into winter 2200-2300kg DM/ha
• []==Pasture cover required by April 1 2500kg DM/ha
Strategic use of supplement
The timing of supplementary feed use is very strategic – it is put into the system in early autumn when grass is growing. This allows the rotation to be extended, and a lot more feed is grown.
This contrasts with the recent trend of extending the autumn milking period by feeding silage late in autumn. Longer lactations require a greater quantity of silage to be fed because you don’t exploit the advantage of longer autumn rotations.
A higher pasture cover at the start of April means less supplement is needed to extend days in-milk. It also avoids feeding out in April or May, when weather conditions might be more difficult, resulting in higher feed wastage.
Plan to avoid spring supplementation. Research shows it is more challenging to make a profit feeding supplements in spring because of substitution and feed wastage. Feeding supplements in spring means cows eat the more costly supplement at the expense of grazing less-expensive pasture, which is then wasted.
Spring management
Calving spread must be planned so all cows reaching their peak intakes near balance date. Calving spread is a combination of the calving date, commonly recommended as 50-60 days before balance date for a pasture-based system, and calving rate.
A spring rotation planner is essential to ensure feed is well allocated over the tight spring period before balance date. There is a fine balance between feed supply and feed demand – this system will always feel tight for grass. Maintaining target residuals, e.g. 1500kg DM/ha, is another key factor, ensuring high utilisation and good quality pasture all year round. Higher pasture covers generated in this system can be carried because excellent grazing residuals are maintained all year, so high covers can still be well utilised because of their high quality.
Identify and achieve critical targets
Some hard lessons have been learned during this low payout period. Costs can’t just be cut by dropping supplements out of the system – stocking rate adjustments, planning to plug feed deficits and timely decisions are very important. Identify factors which are critical to your success, such as:
• Stocking rate and timely adjustments, including culling and drying off
• Target feed covers at key dates
• Condition score at calving – cows at 5 and heifers and second calvers at 5.5
• Grazing residuals at 1400-1500kg DM/ha.
Ensure these key factors are nonnegotiable.
They must be achieved.
Profitability
The pasture-rich farming system provides a robust, resilient and sustainable business model that will survive a volatile range of payouts. It is capable of maintaining a profit in lower troughs of the payout cycle while capturing high profits in higher payout times.
Table 1 demonstrates this general concept. At a high payout, the example top quartile pasture-based farm maintains farm working expenses (FWE) in the mid-$3 range, leaving $3.30/kg MS available for drawings, debt repayment, tax and business growth. In a low payout, FWE will be further trimmed for a survival budget but some money is still available for drawings and-or debt repayment. Major system changes aren’t needed.
Autumn planning determines farm profit, because the early spring feed deficit is filled cheaply from autumn-grown pasture carried forward.
For a profitable system, it is essential to focus on high pasture growth and utilisation, and not production. Profitable levels of production will follow.
The decision-making and planning starts now.
Lynaire Ryan is a business developer for DairyNZ.
