December 22, 2017 update
Dairy farmers in many parts of the country have faced a hot, dry start to summer. We’ve pulled together a list of commonly asked questions to help guide your decisions over the next few months.
1. Stay optimistic. Don’t underestimate the resilience of the farm and the herd, and their ability to recover from this situation.
2. We have had seasons like this before e.g. 2010-2011 (see graph below, the red line is 2010-11) with a good recovery from January onwards.
3. Be positioned to take advantage of any recovery. Aim to have as many cows as possible still in milk when it happens and some supplements still on hand as well.
4. Have a deadline for the expected recovery. For example if the recovery doesn’t occur by March 1 then it’s too late. Focus on next season.
5. Protect pastures, next season’s production and people. Consider staff workload and the need for time away from the farm.
Expect feeding levels under current circumstances to fall i.e. trying to continue feeding 16-18kg DM/cow/day will be expensive and potentially wasteful.
Is it still worthwhile monitoring pasture?
Keep monitoring the grazing residuals. Only use the plate meter to monitor the height of pasture or use the summer equation for DM. More than seven clicks grazing residual (3.5cm) means some pasture is still in the paddock. Less than seven clicks indicates overgrazing, which must be avoided if at all possible. Repeated severe grazings will compromise pasture persistence.
Currently there is often more pasture dry matter than you think still in the paddock. For instance, use the following example to work through your own situation.
- According to DairyNZ’s Facts & Figures a 500kg cow producing 1.4kgms/day and walking 2km per day on flat land requires 178 MJME/day
- Feeding 7kg of supplement (after wastage) and 5kg grass/day, both at 11 ME, supplies only 132 MJME/day.
- This means 46MJ ME coming from somewhere else.
- Some of this could be being supplied by the cow herself in weight loss. Assuming the classic W shape weight profile observed for many NI herds, where there are two periods of weight loss, one after calving, a recovery, then weight loss during the summer.
- 37 MJME is supplied by 1kg weight loss/day. In this example cows would need to be losing 46/37= 1.2 kg LW/day.
- This degree of weight-loss is highly unlikely in mid -lactation. There will be some weight loss, maybe 0.2-0.3 kg/day currently but the cow at this stage of lactation tends to drop production before she loses extreme amounts of weight like 1.2 kg/day.
- If you assume a weight loss of 0.5kg, (19MJME), the rest (46-19=27MJME) is coming from pasture. This is almost another 2.5kg DM/cow being eaten. There is more pasture DM than you think.
How do I avoid overgrazing?
Move cows to a standoff area once the pasture grazing residual has been met. Feed pasture first then take off onto crop (if available) or stand-off area. Shade and water is important so if a choice is available provide access to a paddock with trees or leave the gate open to an area of race with trees.
What happens to feed demand when changing milking frequency?
Aim to feed the same amount per cow as when on twice a day milking (TAD).
Make the change while you still have pasture ahead, earlier rather than later. Cow demand doesn’t change much, energy required for maintenance reduces a little but only due to reduced walking.
What happens to my rotation if milking frequency is reduced?
If already on the correct rotation (30-40 days) no change is needed when changing milking frequency to once-a-day (OAD) i.e. the same total ha offered per 24 hours as on TAD.
For those with problematic cell counts, milking 'three times in two days' is an option that can be used.
Is milking three times in two days (or 14-18 hour milking intervals) a viable option?
This option can be used to help reduce time and energy spent walking and can also help extend the grazing rotation. This is because on many farms you move from feeding four paddocks every two days to three paddocks every two days.
Research on the impact of milking interval on milk yield indicates that the rate of milk secretion is largely unaffected up to about 18 hours – though there is variation between animals. Therefore, if cows are fed the same amount, there should be little to no loss in milk production, when cows are switched from four milkings to three in two days.
Read more on reducing milking frequency here.
Do I buy more supplement and what do I pay for it?
If residuals are under 1400-1500 kg DM/ha good responses to supplement can be achieved, depending on price and total costs. One of the main purposes of feeding supplement prior to rain is to keep some cows milking until it rains and to avoid repeated overgrazing.
Note that feeding lots of supplement will increase demand for water; ensure this is able to keep pace with demand. Consider providing water in the yards/exit race to reduce demand on troughs in the paddock immediately after milking.
There can be a high return from feeding purchased supplements if this means cows are still milking when it rains. For example, 60 days feeding at 8kg DM/day = 480 kg DM/cow @ 30cents/kg DM= $144/cow. $144/$6MP = 24 kg MS required to recoup costs. This would require the cow to milk 24 days at 1kg MS per day post-rain to recoup this.
However there are costs over and above the cost of the feed itself, typically 50 percent on top of the feed cost. In the example above this means the 30 cent per kg feed landed might cost as much as 45cents/kg DM to feed if all costs are accounted for. This increases the cost to $216 and the extra MS needed will be $216/$6MP= 36 kg MS. Either the production per day needs to increase or the time required post rain to deliver the extra MS will be longer, in this case 36 days post rain.
What should I feed my cows during a drought when I have no grass available? Maize? PKE? Grass silage? Minerals?
The cheapest feed available (on a cents/MJ ME basis) as long as the diet has enough fibre, in particular enough effective fibre. For example, if feeding PKE, the cows require an effective fibre source as well (e.g. silage, hay, straw). If there is no grass available and low protein feeds are being fed (e.g. maize silage) then milk production may be limited by dietary protein content.
The cost/benefit of adding protein to the diet needs to be calculated for each farm. In addition, depending on the milk price and the total cost of feeding supplement, it may be more profitable to dry some cows off, rather than try to continue milking. Depending on the type of feed (e.g. maize silage) minerals may need to be added to the diet.
How much can I afford to pay for supplement during the next couple of months?
There can be a high return from feeding purchased supplements if this means cows are still milking when it rains. For example, 60 days feeding at 8kg DM/day = 480 kg DM/cow @ 30cents/kg DM= $144/cow. $144/$6P = 24 kg MS required to recoup costs. This would require the cow to milk 24 days at 1kg MS per day post-rain to recoup this.
There are costs over and above the cost of the feed itself, typically 50 percent on top of the feed cost. In the example above this means the 30 cent per kg feed landed might cost as much as 45cents/kg DM to feed if all costs are accounted for.
A number of risks need to be considered. What if it doesn’t rain early enough? What effect does feeding out this amount of supplement have on staff time and effort, machinery costs etc.
Shall I use supplement already on farm saved for winter?
Ensure you retain three weeks supplement for when it rains, if at all possible. Much of the dry matter left in the paddock will disappear with rain (rot). Aim for 200kg DM/cow.
The remainder can be fed if you’re prepared to dry off earlier at the end of the season to meet your pasture cover and BCS targets for calving or have a confirmed source of feed to replace this.
What do I do for winter feed if I use my winter supplement through the summer/autumn?
- Be prepared to cull and potentially dry off early. Redo budgets to evaluate replacement feed.
- Look for opportunities to graze replacements off longer.
- Apply nitrogen when it rains to help increase pasture cover after summer, and to encourage ryegrasses to tiller – check with contractors and book early.
- Consider the protein levels of supplements e.g. use pasture silage for milkers and maize silage for dry cows as good pasture quality silage will have a higher protein content.
- It may mean considering new approaches to pasture renovation, e.g. under-sowing annuals/hybrids pastures that are recovering poorly this autumn.
- If winter crops are normally used for winter feed, can the farm system and finances work with extra land in crop?
What’s the optimum rotation length for December/January? If I’m not on this, what do I do?
Based on leaf emergence of 11-13 days, a rotation of 33-39 days is recommended as a maximum interval between grazings, and no quicker than 28-30 days. Longer rotations present a risk for C4 grasses (e.g. paspalum, kikuyu) to dominate the pasture in northern regions of New Zealand.
How soon can I PD animals so I can cull empties?
Pregnancy can be confirmed as early as 35 days post conception so PD asap to confirm early calvers and determine likely empties/late calvers that can be removed.
How many cows should I cull and which ones?
Regular monitoring allows you to evaluate options available for stock and feed management based on the most accurate information. On-farm, keep an eye on the weather forecast and benchmark yourself against others to help with decision-making.
Farmwatch – DairyNZ Farmwatch provides farmers with a weekly summary of the on-farm situation observed throughout New Zealand, plus timely advice.
NIWAFarmMet – This is a subscription weather forecast and information service designed specifically for farmers.
Pasture Growth Forecaster – The DairyNZ Pasture Growth Forecaster is an easy-to-use web-based tool to help predict how much grass grows on your farm.
Hotspot watch – NIWA's Hotspot watch is a weekly update describing soil moisture across the country to help assess whether severely to extremely dry conditions are occurring or imminent.
Seasonal climate outlook – NIWA’s air temperature, rainfall, soil moisture and river flow predictions for the coming season.