Laurie and Adele Pottinger aim to run a simple low cost system-1 farm. This has been achieved by reducing fertiliser and imported supplements and matching feed supply to demand.
- Decreasing stocking rate and running the same management policy or feed allocation will only give you increased per cow production from more days in milk.
- Dropping stocking rate by 10 percent meant daily feed intake had to increase.
- Restricting intakes in early lactation can undo what you are potentially trying to achieve.
- The feed budget has higher allowance for milking cows. If pasture growth rates are below average they have room to feed supplement without adversely affecting cows’ production.
- Drying off has occurred in March on three occasions due to dry summers. To provide enough feed, the Pottingers are growing and importing lucerne from the support block (making the farm system-2 according to DairyBase).
- The Pottingers have learnt to feed cows at higher daily intakes.
Before purchasing and farming their hill country sheep and beef farm at Waitomo for six years, Laurie and Adele were 50:50 sharemilking.
The Pottingers purchased their current farm in 2007 with the aim to have a simple low cost system-1 operation (self-contained with support block). This goal still remains combined with a strong focus on environmental awareness.
The stocking rate has been progressively lowered from 3.2 cows/ha in 2007 to 2.3 cows/ha in 2015 since purchasing the farm.
The Pottingers believe in the genetic potential of the herd and understand the benefits of reduced stocking rates from their experiences sheep and beef farming.
Managing a low input system
Since 2007, the Pottingers have aimed for a system-1 farm trying to feed no imported supplement to the herd relying on supplement harvested off the milking platform and dry cows winter grazed on the platform.
To reduce their environmental footprint, the Pottingers have restricted Nitrogen (N) application to 65kg N/ha/yr (targeting 38kg N/ha/yr in 2015/16). They believe there is a need to have a low environmental footprint.
The resulting N leached (as measured by Overseer) is now 31kg N/ha, previously it has ranged up to 29kg N/ha. The Overseer reports were done by Laurie who, over the last two winters, has completed the intermediate and advanced sustainable nutrient management courses. Bringing lucerne into the dairy platform with its high protein percent has increased N loss to water, this is offset over the whole system with N loss on the lucerne block being 14kg/ha. N fixation is 141kg/ha over the whole system and 400kg/ha on the lucerne block.
Stocking rate decisions
“There was no trial and error, just maths and science,” Laurie Pottinger.
Decreasing N inputs from fertiliser and imported hay and baleage required a decrease in stocking rate so that demand meets supply while continuing to maintain pasture quality on a rolling to steep contour farm.
Stocking rate decreases were based on data from DairyNZ’s booklet, Facts and Figures. Initially it was based on targeting 400kg MS/cow which meant feeding 5.1 tonnes/cow/year and harvesting 14 tonnes of crop and pasture.
Many years of feed budgeting and recording pre and post pasture residuals means the Pottingers believe they have a reasonably accurate picture of the farm’s pasture growth potential and matched that to the existing stocking rate.
The Pottingers have noted, “Lowering stocking rate does not mean an automatic increase in per cow production. One needs to have the pasture management skills to do it.”
Matching supply and demand
To make the most of available pasture and maintain quality, Laurie:
- Records, using visual assessment, pre and post grazing residuals for every grazing
- Uses the spring rotation planner and a feed budget to drive the desired level of intake and pasture quality
- The timing of the spring rotation is earlier than most farmers would have” as the farm is north facing resulting in good early spring growth.
Lucerne is planted on the support block and chicory and clover on 10 percent of the milking platform to help alleviate poor summer growth and provide high quality feed during summer.
To utilise the chicory, from early December the Pottingers have gone to 16 hour milking instead of the normal once a day. This has extended grazing round by 6 to 37 days.
The Pottingers have learnt to feed cows at higher daily intakes. In the past they would have been happy if the cows were eating 19kg DM at peak, now, they believe they are eating 22kg DM effectively this has taken up a lot of the surplus pasture created by reducing stocking rate and maintained pasture at previously harvested levels.
Their feed budget has milking allowances of 18kg DM/cow/day in August and 20kg DM/cow/day in September. They have a targeted pasture cover on “balance day” of 1,950kg DM/ha; if growth rates are below average they have room to reduce these figures without adversely affecting the cows’ body condition.
A low stocking rate and moderately fast winter rotation of 80 to 90 days means in the winter the Pottingers can easily manage the cows and leave them on the paddocks.
- The lower stocking rate better fits pasture supply over winter and early spring.
- Chicory and clover have been a major win. The October to November growth averages 60kg/day and with 10 percent of the farm dropped out of the grazing round leaving the Pottingers with 54kg/day - a nice match with the cows eating 22 to 22.5kg DM/day at a 2.32 cow/ha stocking rate.
- The quality chicory diet helps mask any summer pasture management mistakes (i.e. not achieving residuals) which affected pasture quality.
- Having 10 percent of the farm in chicory meant surplus pasture was reduced resulting in cost savings from less contracting and N use. This effectively covered the chicory establishment costs. Making large amounts of silage in the past didn’t work well due to contour, availability of contactors and weather.
- Reliance on N-boosted grass and supplements has reduced.
- Lower stocking rate over winter meant cows could be grazed on a bigger surface area per cow per day resulting in minimal pasture damage and better cow condition at calving.
- Higher body condition score and better feeding in early lactation has resulted in reducing time to oestrus. This fits nicely with the Pottinger’s policy of nil veterinary intervention over mating.
- Cow size has increased resulting in cull cows being more valuable. Average carcase weight of the culls this year is 192kg. The herd breed mix is 53.5% friesian and 46.5% jersey.
- Total expenses related directly to the cow (animal health, artificial breeding, herd testing and grazing) have reduced with a lower stocking rate.
- Fatter cows have a higher incidence of milk fever.
- Managing pasture surpluses on a hilly farm is more restrictive and challenging.
- Late spring or early summer pasture surpluses risk reduced growth rates in a dry summer.
- A long lactation is required to make the system work. Hence, a dry summer has a major impact because the Pottingers are more reliant on obtaining days in milk.
Other nutrient leaching reduction strategies
- Wetter or steeper contour paddocks:
- Are grazed over winter with lighter stock when weather conditions allow
- Have no winter cropping
- Generally do not have supplement fed until closer to calving and only on the better contoured paddocks.
- Most paddocks have two permanent troughs so over winter cows have access to water without the need for portable troughs. The Pottinger’s found using portable troughs creates more mess than permanent troughs therefore no longer use them.
- To protect pastures and capture urinary N, Laurie stands cows on the cow shed when paddocks are too wet.
- A lower stocking rate and a winter rotation of 80 to 90 days allows the Pottingers to easily all grass winter as the cows have 40 percent larger surface area (m2/cow) on pasture and the lower stocking rate reduces pasture damage. Ironically, the Pottingers believe it would create more damage if they were pulling cows off difficult contours.
- Critical source areas (CSA) (gullies and swales) are protected by ensuring grazing direction is towards the CSA allowing these areas to be grazed last.