- There are many different motivations for using full season OAD milking; this influences the productivity/profitability change when moving from TAD milking.
- Generally farmers that see the most benefit from OAD are those whose current resources are putting stress on a TAD system.
- Before changing your farm system it’s important to assess the potential benefits and determine whether it fits with your future aspirations and goals. So when assessing OAD milking as an option it is recommended that you complete a budget.
Is full season OAD right for me?
Use this decision matrix as a guide to see if you may benefit from full season OAD milking, all you have to do is answer 10 questions - start here
After completing the decision matrix, you may like to read more detailed explanations about why farmers have switched to full season OAD milking. These reasons can be grouped into two categories, farm and labour considerations.
Managing capital constraints:
- Increasing herd size within existing dairy (managing long milking times)
- Integrating new or previously inaccessible land, e.g. poor races, water reticulation etc
Reducing energy requirements and lameness from walking:
- Where the farm has long walking distances
- Where paddocks have an uneven contour or there are large differences in elevation between paddock and the dairy
- Where the walking in the afternoon coincides with times of high temperature/humidity
Minimising cow wastage:
- Reducing culling due to reproductive performance, lameness
- This may be related to the reasons described above
Improving grazing management:
- Irregular paddock sizes make hitting target residuals difficult when constrained by an afternoon milking
- Cows spend more time on pasture
- Better matching feed supply/demand on farms with relatively flat pasture growth curves
Increasing labour flexibility:
- More productive use of rest of day, tasks not interrupted by an afternoon milking
- Potential for 24hr grazings (i.e. no animal work till next morning)
- Can handle more cows per FTE
Improving staff satisfaction:
- Less hours milking
- Improved staff retention
- Spending more time with family
- More time for off-farm hobbies
- Reducing physical stress so can stay on farm longer
What to expect from full season OAD
Data from the Dairy Industry Good Animal Database (DIGAD) has been used to compare some of the physical differences between herds milking OAD and TAD, giving you an idea of what you can expect after making the switch.
The results from the data analysed is indicative only as cause and effect relationships cannot be determined, i.e. we do not know what else OAD farmers have changed along with milking frequency.
Herds milked OAD had more concentrated milk, higher SCC and lower milksolids production per cow. This does not account for any change in stocking rate.
- Herds milking OAD had 5-8% higher fat%, protein% and milksolids %
- The difference in milksolids/cow was more pronounced in the first season. The difference between herds in their 4-5th season on OAD and TAD was not significant
- Somatic cell count (SCC) was significantly higher for OAD herds.
OAD herds in general had better reproductive results than their paired TAD herds.
- AI mating length was about half a week shorter than TAD with fewer inseminations
- This equates to about 37 fewer AI straws for a herd of 470 cows. The trend for using fewer straws was consistent for first and second calvers.
- Calving spread differed depending on the number of years the herd had been milking OAD; little difference in season 1 (determined during previous season); for season 2 or more a significantly higher higher % of cows calved in the first 3 and 6 weeks
- 6-week in-calf rate and not-in-calf rate was difficult to determine from the dataset
Note: with more cows calving earlier there will be an increase in feed demand in early spring.
Herd age structure and culling decisions
Herds milked OAD have a similar age structure, and removal and replacement rate to TAD herds but the removal reasons differed.
- OAD herds had significantly fewer animals leaving the herds due to being empty (not pregnant) or due to management reasons, e.g. poor fertility, old age, traits other than production
- More animals were leaving OAD herds due to low production, udder and mastitis related causes.
It is important to note that when a farmer removes an animal from the herd that only one reason can be selected, so if the animal was both empty and a low producer then it may have been recorded as a low producer. The default reason is “other” so many farmers may not have selected the specific removal reason.
Financial and systems
There is limited data available on OAD in DairyBase. Using data from the 2013/14 season the following observations are made:
- OAD farms are a similar size and have a similar stocking rate to TAD farms
- OAD farms are more labour efficient
- OAD farms harvest less pasture (possibly due to land capability) and produce less per cow and per hectare
- OAD farms consequently have less revenue and lower expenses
- OAD farms have lower profit/ha – expenses are not low enough to offset the lower revenue
- Although there is less capital tied up in OAD farms the return on capital is slightly lower (5.8 v 6.8%).
Another dataset was published in 2007 that compared the financial performance of 22 farms that has switched from TAD to full season OAD milking. The authors of this paper reported:
- a 25% reduction in farm working expenses upon switching to OAD
- a 6% reduction in total milksolids production
- that farmers switching to OAD milking for lifestyle reasons tended to make lower financial gains than those seeking further farm development
The full paper ‘Can you make money milking OAD’ can be read here.
Making a successful transition to full season OAD
The largest loss of production (potentially 20% per cow) occurs in the first season. Careful planning and preparation during the final season on TAD are important to making a successful transition and minimise the adverse effects in year one of OAD.
Drying off at the end of the final season
- Take this opportunity to eliminate/control/cull any mastitis problems, and cows with weak udders, before OAD begins.
- If there is evidence of a mastitis problem in the herd (e.g. herd SCC above 250,000), serious thought should be given to the use of dry cow therapy and teat-seal on all cows; and the use of teat-seal in the heifers, about 4 to 5 weeks before calving for their first time, should also be assessed.
- At the very least, stick to the guidelines given by SmartSAMM, with respect to treatment and culling.
- Including a high % of replacements into the herd will enable more voluntary culling; and 2-year-olds generally have lower SCC than older cows, and higher BWs. But 2-year-olds produce about 25% less per cow than mature cows, and their milksolids yield is decreased by OAD to a greater extent than is the yield of older cows.
Source: Lower North Island OAD discussion group
- OAD herds have more Jerseys and crossbreeds and less Holstein-Friesians (DIGAD* data).
While cause and effect cannot be determined, the analysis of DIGAD data may indicate farmers believe Jerseys are more suited to OAD and have increased the proportion of Jerseys and crossbreeds in their herds, or alternatively it may mean that Jersey farmers have been the early adopters of OAD.
*DIGAD Dairy Industry Good Database
- Good udder conformation is especially important under full season OAD
- Cull/sell cows that have a record of clinical mastitis and/or high SCC before OAD begins.
- OAD herds have more Jerseys and crossbreeds and less Holstein-Friesians (DIGAD* data).
Stocking rate and pasture management
Decreased milk production per cow during the first season of OAD reduces the feed requirement of the cow. To ensure maximum pasture utilisation stocking rate may be increased but this should be done with caution.
In the first year or two on OAD, an increase in cows/ha (by 5 to 10%) is often recommended to compensate for culling unsuitable animals, the expected decreases in pasture eaten per cow and milk produced per cow.
If you were overstocked on TAD, i.e. minimal/no spring surplus and consistent low grazing residuals, no increase in stocking rate may be required.
After the first season or two on OAD and unsuitable cows have been culled and per cow production begins to increase it may be no longer necessary to carry additional cows.
You will quickly know if you have got your stocking rate wrong:
- Too low – large spring surplus that needs controlling
- Too high – no spring surplus and low grazing residuals
Another consequence of getting stocking rate is too high is the likely decrease in pasture intake and yield per cow; in this case, milksolids yield per cow would be depressed by OAD and by underfeeding.
So, any increase in stocking rate should be calculated carefully, to ensure that there will be enough cows on-farm to enable early culling, to fully utilise the pasture, but without over-stocking the farm.
If you initially opt not to increase stocking rate and find you have excess feed you will need to decide what to do with it:
- Feed remaining cows better – a good option if you were overstocked anyway/per cow production was below district average.
- Increase cow numbers.
- Become more self-contained – i.e. wintering more cows on or retaining young stoc
- Sell surplus feed – either as standing grass/crop or baleage/hay/silage.
Cows milked OAD can be successfully managed with either 12 or 24 hour grazing. The key determinant of which you choose will be paddock size and personal preferences.
On farms with a large range in paddock sizes OAD increases the flexibility of when cows can be moved during the day, potentially making it easier to achieve target grazing residuals. Alternatively, some farmers don’t want the hassle of moving cows in the afternoon so choose 24 hour grazing.
Quality and quantity of feed on offer is of greater importance.
- Cows milked OAD are more sensitive to feed deficits and declining pasture quality and respond by reducing production.
- When additional feed is available or pasture quality improves OAD cows are less likely to increase production, instead they use the additional feed for body condition score gain.
Pasture management for cows milked OAD is critical to the success of the system. Any mistakes with feeding will quickly be seen in the vat and are often difficult to correct.
Cows milked OAD in general dry off in better condition that TAD cows. If you are purchasing winter grazing do so on a kg DM/head/day basis not per cow/week. This way you can specify the level of feeding required and will not be paying for feed you don’t need.
Milking machine and milk cooling
On OAD, udders are likely to be at maximum capacity and therefore, during milking, the rate of milk flow through the milking machine will be faster than on TAD. These conditions may necessitate some changes in the machine.
- Cup slip can be a problem on OAD; seek advice from experienced OAD farmers or from milking specialists, about the type of teat-cup liner, long milk tube, and milking cluster that have been found to work effectively with cows milked OAD. Predominantly it is the liner that may need to be changed.
- Ensure that the machine’s vacuum level is stable, and at the correct level, during the whole milking; the machine must be able to hold vacuum with a higher milk flow. This is potentially an issue with a long 50 mm milk line.
- The milk pump and receiver must have sufficient capacity to cope with the faster rates of milk flow expected on OAD. Cows milked OAD have a rapid letdown and flooding of the milk line has been a common problem in older sheds.
- The plate cooler and refrigeration unit must have sufficient capacity. Refrigeration is particularly a problem on daily collection where all the milk enters the vat only once. If a silo is 60% full at 18°C it will take 3 hours to get to less than 7°C. A cooling tower or chilled water may be required to ensure compliance at pick up.
Cows milked OAD take longer to milk – approximately 2 minutes. If milking is already taking 3+ hours you may need to reconsider staff tasks to ensure milkers don’t become fatigued during the milking process i.e. staff swapping roles half way through milking. In herringbone dairies slow milkers may need to be managed separately to prevent every row being delayed.
Mastitis and treatments
Cows milked OAD or TAD are at a similar level of risk of developing new infections – milking OAD does not by itself increase the risk of mastitis.
After cups-off, it is not possible to inspect the teats/udders closely for the next 24 hours, much longer than on TAD. This longer inter-milking interval may enable mastitis infections to become more firmly established before the next milking.
Somatic cell count
Cows milked OAD have a somatic cell count (SCC) that can be twice as high as cows milked TAD.
This difference starts to show up once cows have moved beyond peak lactation (weeks 6-8 after calving) and remains until the end of lactation. There is likely to be greater increases in SCC during the second half of lactation, which may require high SCC cows to be dried off early.
Dairy farms have shown that it is possible to supply high quality, low somatic cell count milk in spite of OAD milking. The best way of achieving this is to keep SCC low in first half of lactation, meaning days in milk can also be maximised.
Preventing mastitis on OAD
- During milking ensure that teat cups are aligned correctly on the teats, and that they remain firmly in place without slipping.
- Before cup removal ensure that all udders/quarters have been milked-out evenly.
- After cup removal look for, detect and attend to, any abnormal quarters (e.g. full/hard/hot), even if cups are removed by automatic devices.
- Implement teat spraying during lactation and improve the degree of teat coverage with teat sanitiser
- More regular stripping of the herd
- The use of dry cow antibiotic therapy at the end of lactation will reduce the existing infection levels and lower the risk of calving with mastitis in the following season.
Detecting and treating mastitis on OAD
Detection by regular herd testing and use of SCC information is an important tool for keeping your SCC levels within appropriate levels.
Cows with high SCC should be checked for mastitis by stripping out the foremilk and examining for visual signs, or by using the Rapid Mastitis Test (RMT) or by testing foremilk conductivity.
Advice on sub-clinical treatment options should be sought from your local veterinarian.
Treat clinical mastitis as you would a cow being milked TAD. Antibiotic treatments with 12 hr treatment intervals should be avoided. Consult your veterinarian for drugs more suited to OAD, including 48 hour treatments.
If a product is not registered for OAD milking, use the number of milkings recommended for TAD. For example, if 48 hours & 4 milkings recommended on TAD, then use 4 milkings, or 96 hours, on OAD; that is, the withholding time on OAD will be twice as long as for TAD. Consult your veterinarian for drugs with shorter withholding periods.
Seasonal herd management
Milking OAD can bring some additional her management considerations.
Cows can be milked OAD from the day they calve. Fonterra’s rules state that colostrum from each cow should be withheld from the vat for at least 8 milkings, equivalent to 4 days for herds milked TAD.
While the newly-calved cow still in the colostrum herd, check all quarters/cows with the Rapid Mastitis Test (RMT). Do not put a cow’s milk into vat unless RMT indicates a low SCC.
It is advisable to inspect newly-calved colostrum-cows twice a day, to minimise losses e.g. from milk fever. If dusting pastures in wet weather e.g. with magnesium chloride, do it twice a day.
With cows only visiting the dairy once daily there is less chance to observe heats during mating. Most OAD farmers use tail paint to assist with detection of cows on heat; some use scratch pads as an additional device.
Some OAD farmers observe cows and their tail paint for signs of heat only at the one milking per day, while some also observe the cows while they are undisturbed in the paddock.