Average Pasture Cover Dry Off Targets
Discussions have arisen with the unusually high average pasture covers currently experienced on farm. Click HERE for the autumn feed budget for SDF and HERE for a blank template to work thorugh your own numbers. http://www.dairynz.co.nz/feed/feed-management-tools/feed-budgets/
Based on the feed budget with the current assumptions the APC at dry off sits around 2300KgDM/ha obviously well in excess of our usual target of 1950-2000KgDM/ha. At this stage the herd can milk into the 1st week of June. We are caucious that the long run pasture growth rates for May wind down from 28KgDM/ha to 19KgDM/ha therefore current pasture growths of 59KgDM/ha are well above our 8yr average. At any stage a run of frosts or a sudden cold snap could throw the budget out.
Looking at a range of scenarios for APC at dry off and the implications of this for APC targets at calving the following shows:At current predictions 2300KgDM/ha dry off plus winter growth 552KgDM/ha = 2852APC at 1st AugSDF APC target for dry off 2000KgDM/ha plus winter growth 552KgDM/ha = 2552KgDM/ha APC at 1st Aug1800KgDM/ha dry off cover plus winter growth 552KgDM/ha = 2350KgDM/ha APC at 1st Aug
*Winter Growth Rates
June averages 9.5KgDM
July averages 8.5KgDM
The other key APC target for SDF is APC at Balance Date (Pasture supply matches herd feed demand). Click HERE to work out APC at Balance date for your own farm. http://www.dairynz.co.nz/publications/farmfacts/farm-management/farmfact-1-84/
SR x intake x round length x 0.5 + residual = APC at Balance Date
2.6cows/ha x 16KgDM/cow x 25 x 0.5 + 1600 = 2120KgDM/ha
The average pasture cover was measured on the 17th May and was estimated to measure 2531 KgDM/Ha. The target APC is 2295 KgDM/ha.
Pasture growth rates were then measured to estimate an average of 38 kgDM/Ha/day.
SDF prefers not to adjust the formula used in the Pasture meter from week to week as we feel this is effectively manipulating the data to have it say what we want it to say. This is more of a risk to the pasture management on farm than a small 1-2KgDM/cow/day variance in pasture intakes offered. We prefer to factor this variance into all of our grazing and supplementary feed decisions and using the post grazing residuals, liveweight and milk production as a more accurate guide to feeding levels.
The average stocking rate for the previous week was 2.3 cows per hectare.
How to determine feed intake per cow per day? Refer Dairy NZ Facts and Figures
How to calculate pre-grazing cover
(Stocking rate x Intake from pasture x Rotation) + Optimum residual = Pre-grazing Cover.
___ cows/ha x ___ kgDM/cow x ___days) + _____ kgDM/ha = _____ kgDM/ha
Below is the comparison of pasture cover for this season and the two previous seasons.
How to calculate target APC required
Pre Grazing cover + desired residual / 2 = Average Pasture Cover Target
SDF current workings;
3040 kgDM/ha + 1550 kgDM/ha / 2 = 2295 kgDM/ha