Should you be concerned?
- From your pre and post grazing cover estimate your average pasture cover (APC) if not known
- Calculate your feed demand for pasture per hectare for the next 7-10 days
- Does the estimated growth rate for your APC equal or exceed your feed demand
- If not you have a deficit.
If you have an estimated cover of 1700 kg DM/ha (going into 2100-200 kg DM/ha cover and leaving residuals less than 1400kg DM/ha, stocked at 3.0 cows/ha at 18kg DM/cow/day you need 48kg DM/ha to meet demand.
The predicted growth rate (including nitrogen that has been applied since the snow) is 35kg DM/ha. Therefore you are in a feed deficit. Note that if on a very fast round residuals maybe 1400kg DM/ha or more. However, very quickly APC will drop and pre-grazing covers will be lower - not a good situation to be in at mating.
Which describes your current feed situation?
|Does your feed demand of pasture exceed the expected growth rate below for the APC (incl 40- 50 kg N/ha)|
|2000 or less||1300 or lower||1600 or lower||20 (enough for 1.1.cows/ha)
|2100-2200||< 1400||1700||35 (enough for 2.0 cows/ha)|
|2200-2300||1400 or less||1800||45 (enough for 2.5 cows/ha)
|2300-2400||1500 or less||1900||50 (enough for 2.8 cows/ha)|
|2600 plus||1500 plus||2000 plus|| 60 (enough for 3.3 cows/ha)
NB: Feed demand based on 18kgDM pasture/cow/day
Pasture Cover Affects Pasture Growth Rates
Figure 1 shows how low average pasture cover (APC) results in limiting spring pasture growth rates.
The lower growth rates are due to the pastures being grazed before the 2-2½ leaf stage. Plant growth rates are maximised by grazing before the appearance of the fourth leaf or canopy closure (whichever occurs first) as shown by Figure 2.
If have low APC then need to get rotation out to at least 25 days The quicker the rotation the longer the time in a feed deficit.
Management Options for Low APC
- Hold slow rotation 25-28 days to maximise pasture growth rates. This can be achieved by:
? Feeding supplement or
? Pinch the cows
- Speed up rotation and underfeed cows at mating (death spiral)
Maximise Pasture Growth Rates
- Do not speed up rotation; hold a 25 -28 day round until APC is 2000 kg DM/ha
- Feed supplement to get cows into a positive energy balance
- Protect future growth rates - nil pugging damage
- Apply nitrogen and sulphur (if farm low in sulphur) at 40-50 kg N/ha to as much of the farm as possible; getting it on in 1-2 applications is preferable to following the cows
- Consider using gibberellic acid formulations to boost feed at mating
- Need to apply within 5 days of grazing
- Apply with N as responses are additive
- Refer DairyNZ Farmfact: ProGibb SG (1-26) for more information
- Consider milking cows every 16 hours to hold rotation until APC over 1900/2000 kg DM/ha
Minimise impact on milk production and cow condition
- The priority cows are
2. First and second calvers
- Colostrum cows can be grazed in front of the herd
- Submission rate of first and second calvers will be 20-30% less than MA cows where competing for limited feed (grazing residuals less than 1400kg DM/ha for 4-5weeks)
- Milk first and second calvers in separate herd
- Order enough supplement for the next 2 weeks, the situation can change very quickly
- If have baleage or silage, supplement with grain or PKE to get silage to last for next 10-14 days
- In extreme feed deficits the first criteria for feed purchase is practicality to feed, then price
- Contact Federated Farmers 0800 327 646 to find out what feeds are available
- Response to supplement decreases as feed deficit is filled (refer Table 1)
- Monitoring APC and residuals will be critical to ensure supplement feeding stops before creating a feed surplus. If in doubt stop feeding.
Get a Plan
- Assess your situation, seek advice and plan - this reduces stress and time making decisions.
- Estimate the amount of supplement you need for next 2 weeks (refer Feed Budget)
- Review plan weekly. If you take action now your feed position can change very quickly.
- Milking cows OAD takes pressure off people and gives time to feed stock
- OAD milking does reduce milk production both immediate and for the season the longer the period of OAD milking. Therefore review OAD milking weekly. Refer Table 2
- 16 hr milking maybe an option to manage workload with little impact on milk production.
Minerals & Calves
- Supplement cows with magnesium, this is very important when cows are not being fully fed
- Add magnesium to silage, PKE, grain.
- Add limeflour to milkers only if feeding high rates of grain.
Nitrogen and Fertiliser
- Apply nitrogen at 40-50kg/N ha (90-110 kg urea/ha) as soon as possible to as much of the farm even if have been following with N - get it on everyday counts
- Low covers (<1800 kg DM/ha) consider applying nitrogen and sulphur eg. 50% urea and 50% SOA at 150kg/ha to all of the farm. Aerial spreading is a good option
- Seek advice on spring fertiliser as due to the very wet spring other nutrients (sulphur and potash) may be limiting when conditions are drier and warmer.
- Good feed if able to source especially if feeding grain as forage feeds reduce risk of acidosis.
- Likely to be expensive however, supplement should only be required for short period and if animal health (acidosis) or animal welfare are at risk cost differential not a factor.
- Allow for utilisation of 60-70% if feeding on wet paddocks, especially grain silages (cereal and maize)
- Quality can be highly variable especially with cereal silages, consider this when purchasing and feeding out.
- PKE is a good feed as it is able to be adlib fed
- Ideally feed in bins. You can also use trailers
- To get intakes of 3kg PKE/cow plus, cows need to be fed adlib and access to water and have enough bins to give all cows a chance.
- When feeding in paddock have bins away from water trough to encourage cows to go and drink and give other cows a chance
- Can feed in exit race at cowshed and on yard in bins; Can feed with silage; add PKE when wagon half filled with silage or put PKE in first so mixes with silage (allow for 70% utilisation)
- Can feed on side of yard - to improve utilisation you need solid back and outriggers
- Can get mixes with grain (70%PKE; 30% grain). Need to ensure well mixed to prevent gorging and acidosis with the grain.
- If have in shed, feeding system can get intakes of up to 3.5kg grain per milking i.e. 7kg/day for big cows that have been gradually introduced to grain
- To achieve these intakes may need to slow platform down to give cows enough time
- If no in-shed feeding system, need to prevent gorging or cows will get acidosis
- Can feed under fence line or spread thinly on yards or add to silage as for PKE
- Feed pasture, silage, straw before offering grain to reduce chance of acidosis
- Need to feed so that individual cows don't gorge as risk of acidosis.
- Can buy in bulk and fill water troughs allowing cows access to the troughs as they leave the shed, however dangerous if cows hungry as individual cows will gorge.
Once a Day Milking (OAD)
Milking OAD is an option to save time and reduce stress on people. OAD milking decreases immediate milk production by approximately 20% in early lactation with the yield loss increasing to 30 (and up to 50% in heifers) as the duration of reduced milking frequency increases up to 10 weeks. Milking OAD has a carry-over effect on the potential milk production for the season. This increases the longer the time cows are milked OAD as shown in Table 2 below, with the effect being significant if employed for periods longer than 3 weeks.
Table 2: Effect of OAD milking in early lactation on immediate and carryover milk production responses
|Carry over loss||0 to <5%||5-10%||10-15%||-|
|Full lactation loss||1-2%||7-12%||12-20%||30%|