OAD milking can be used either strategically (long-term) as the overall farming system or tactically as a short-term response to adverse seasonal conditions.
Reasons to consider OAD milking
There are a number of reasons to consider OAD, the advantages of which will depend on the current farm system or layout e.g. long distances walked by cows.
- Less time spent milking cows
- Reduce staff pressure
- Feed shortage
- Stock health (lame cows, light cows, heifers, milk-fever prone cows)
- Reproduction (non-cyclers, heifers or whole herd in a feed shortage)
- Small dairy shed for herd size
- Farm layout (walking distance to shed)
OAD milking options
Full season OAD is an option that requires the most planning, as it involves a change to the overall farm system.
Early Lactation OAD is often used to help staff manage multiple mobs, help with spring labour shortages and reduce the pressure on farm during periods of adverse weather.
- Milking cows OAD for 3 weeks during early lactation.
- Loss in milk production: OAD 7% less than TAD milking, with the full season milk production down 4.3% compared to TAD.
- The cow’s energy status will be improved.
- Milking cows OAD for 6 weeks during early lactation
- Loss in milk production relative to TAD: OAD 12% less MS per year
- The cow’s energy status and BCS will be improved beyond 30 days in milk
- Cows on OAD still experience a post- calving BCS loss, but by 5-6 weeks OAD cows had achieved greater improvements in BCS
- Differences in energy status and BCS are not sufficient to alter reproduction. It remains unclear if short-term OAD milking can improve reproduction when cows calve below target BCS and/or are underfed, causing poor BCS during early lactation.
- Milking cows OAD in the early lactation period with a feed restriction will cause an additional loss in production.
See the June 2013 Technical Series for OAD trial information
OAD post-Christmas is a common strategy in a dry summer. When done early enough and with enough feed it can also be used to extend lactation.
- Takes the pressure off cows by reducing energy expenditure and the incidence of heat stress in summer, especially if walking long distances to be milked.
- Reduced stress on staff, as well as giving managers more time to plan and manage.
- Help cows reach body condition score (BCS) targets during dry summer periods and sets the farm up to maximise days in milk from autumn pasture growth.
Milking three times every two days (about every 16 hours) is another option in a dry summer to help reduce energy spent walking and can also be used to slow down the grazing rotation.
It is better to plan to milk OAD before feed runs short than to be forced into it by a severe shortage of feed.
Impact of milking OAD from mid-January on
Research data indicates:
- BCS gains
Cows moved to OAD in mid-January gained about ¼ BCS unit more before dry-off (in about three months) compared with cows that continue to be milked twice-a-day (TAD). Cows need to be milked OAD for at least 6 weeks before gains in BCS are apparent.
To optimise the BCS benefits from OAD milking cows need to be well fed.
- Little impact on feed intake
Moving to OAD will have little impact on feed intake with research indicating cows milked OAD ate about 3% less than those on TAD.
This small decrease in intake needs to be considered if milking OAD during summer. If the decrease in feed intake is not enough to reach target pasture covers and to balance feed supply and demand then other options (e.g. culling, drying-off some cows, feeding supplements) need to be considered.
- Drop in production
Production per cow drops by about 10%. However as the drop in production occurs after production has passed its peak, the overall impact on the season’s production will be less, around 4%.
When to milk cows OAD
Average per cow milk production can be used as a trigger to determine when cows can be switched to OAD.
Average herd production of 1.2kg MS/cow is a figure that many farmers use.
There is limited research on this topic and the trigger point will depend on the breed, Breeding Worth, somatic cell count, BCS and the range of per cow production in the herd.
Management during transition to OAD
Continue feeding cows well:
- Maintain feed quality and quantity at twice a day levels for at least the first week.
- If milksolids per cow drops by more than 15% in the first week, this may indicate that the cows are being underfed. Monitor pasture residuals and if this is the case, increasing the feed supply (pasture or supplements) or reducing the feed demand (culling, drying off) may be required.
- Underfeeding during the transition to OAD milking may exacerbate somatic cell issues as the somatic cells will be concentrated in a smaller volume of milk.
Mastitis can be an issue:
- Remember to ensure the herd’s average somatic cell count (SCC) is below 200,000 when switching to OAD – for a few days SCC can rise to double that of cows milked twice-a-day.
- Staggering the herd’s transition to OAD can help to avoid a big spike in SCC.
- Dry off high SCC cows or keep on twice-a-day.
3 times every 2 days - an alternative to OAD
Research on the impact of milking interval on milk yield indicates that there are no production losses when the interval between milking is no more than 18 hours. Therefore, if cows are fed the same amount, there should be no production loss when cows are switched from four to three milking in two days.
16 hour milking may be another option in a dry summer to help reduce energy spent walking and can also slow down the grazing rotation. This is because cows generally are offered the same size break at each milking but spend a longer period of time in each break.