Once a Day Milking as a Short Term Strategy

August 2013

A DairyNZ study into the uses of Once a Day milking as a short term option for dairy cows

The benefits and costs of milking cows once a day.

DairyNZ scientist Jane Kay says that once a day (OAD) milking is a management strategy that famers sometimes use during periods of high workloads, during feed shortages or during the final few months of lactation. Several experiments have been conducted at DairyNZ research facilities investigating the short term use of OAD milking during these situations.

The research found there were both short and long term losses in milk production when cows were milked OAD for short periods in early lactation. There were also additional losses in milk production when underfed cows were milked once a day. During a severe feed shortage milking cows OAD did not stop the loss of body condition; however it did improve energy balance and reduce the risk of metabolic disorders.

During late lactation, cows milked OAD produced 20% less milksolids; however, these cows put on an additional .25 BCS units. In addition, there was no difference in intake between cows milked OAD or TAD during this period.

OAD milking can reduce stress on staff, improve lifestyle and free time to do non-milking tasks such as feeding out.

Milking cows OAD from calving for 3 or 6 weeks can reduce the loss of BCS after 4-5 weeks of lactation.

During periods of feed shortage, OAD milking can improve energy balance and reduce the risk of metabolic disorders.

OAD milking during mid-late lactation can take the pressure of cows that have to walk long distances in the hot afternoons and enable body condition score (BCS) targets to be met.

All research indicates that OAD milking does not reduce feed demand compared with cows milked TAD, even during a feed shortage.

Recent data from DairyNZ combined with previous research shows that the longer you milk cows OAD from calving, the greater the immediate drop in milk production and the greater the subsequent carry-over and total season loss.

Individual cows milked OAD for three weeks in early lactation produced 15% less milksolids (MS) during that period and 7% less total MS over the full season than cows milked TAD. By using the DairyNZ whole farm model, this translates to a MS production decline of 2% over the full season in the situation where the herd is milked OAD for the first three weeks of calving. This equates to approximately $12,600 annual revenue lost for a 300 cow herd (assuming 350 kg MS/cow per year). Trial cows milked OAD for six weeks after calving produced 12% less MS (on an annual basis) than those milked TAD.

When cows were underfed and milked TAD for 3 weeks in early lactation, they produced 26% less milksolids during that period and 9% less MS over the full season compared with cows that were well fed during this period. If the underfed cows were milked OAD MS production was reduced by a further, such that underfed cows milked OAD produced 36% less milksolids during the 3-week treatment period and 13% less MS over the whole lactation compared with well-fed cows milked TAD. This indicates a further 10%, the negative effects of underfeeding and milking OAD are additive.

Advice to farmers is to be aware of both the costs and benefits of short periods of OAD milking, especially in early lactation. If you are going to milk OAD during early lactation, minimise the period of OAD milking and ensure cows are not underfed. This is vital to reduce the negative effects of OAD milking on milk production and to gain the benefits of OAD milking on BCS and energy balance. If cows are to be milked OAD during late lactation, may particular attention to pasture allowance to ensure milk production is not further compromised and that BCS gain is maximised.