Since the beginning of commercial dairy farming, new ideas to improve the industry have often been ridiculed. But some of these supposedly outlandish ideas have gradually become the norm. Lloyd Phillips takes a closer look at the new concept of once-a-day milking that’s emerged out of New Zealand.
Dairy farmers are always
looking for new ways to improve productivity and efficiency. But when calves were made to suckle their dams eight to 12 times a day to stimulate milk let-down and the idea of manual teat stimulation before milking was suggested, it wasn’t taken seriously. Today, manual and even no-teat stimulation just before milking is common practice.
The relatively new concept of once-a-day (OAD) milking in commercial dairy operations is generating significant interest in New Zealand and Australia. It was presented at the 2009 SA Large Herds Conference recently by Professor Colin Holmes, a New Zealand-based dairy consultant and dairy scientist.
Twice-a-day versus once-a-day
Holmes points out the commonly used twice-a-day (TAD) milking system on most commercial dairy farms creates a number of problems including long periods spent milking cows, significant staff requirements, large quantities of costly feed, health threats to cows, weakened reproductive systems, large milking facilities needed and excessive walking between pasture and parlour.
“Twice-a-day milking dominates life on a dairy farm and its demands make it difficult to attract and retain young entrants in the industry,” says Prof Holmes.
“Once-a-day milking (OAD) reduces a dairy farm’s major tasks by 50% and also creates more flexible work schedules, benefiting both employers and employees. OAD can even be more profitable than twice-a-day milking.”
Other advantages of OAD put forward by Prof Holmes include that cows walk half the distances between pasture and the milking parlour each day, thereby reducing risk of lameness; they can be grazed on remote pastures and there’s less stress on them and staff.
OAD cows eat slightly less than TAD cows, but are in better body condition and when a herd is expanded, the milking parlour need not initially be expanded.
“Regarding the compatibility of OAD milking with large grazing systems, it may reduce a cow’s daily milk yield, but it also reduces its daily feed intake,” says Prof Holmes. “A slightly higher stocking rate can be used in an OAD system than in a TAD system, negating any reduction in a herd’s milk production and milk solids yields.”
Considering genetics and mastitis risk
An important aspect of the OAD system is selecting the right genetics, as the majority of dairy cows today are bred for TAD milking. Therefore, a dairy farmer changing to OAD must select cows that can tolerate the dramatic physical changes in the
functioning of the mammary gland, the adjustment of the immune system and the changes in milking and nutritional management.
According to DairyNZ, which represents New Zealand’s dairy farmers, cows milked OAD or TAD have the same risk of developing mastitis. Milking OAD doesn’t increase the risk, but cows tend to show more visible signs of clinical mastitis. “Research shows that cows milked OAD can have a somatic cell count (SCC) twice that of cows milked twice a day,” DairyNZ explains. “This is equally true for uninfected cows, cows with a sub-clinical infection and cows that have had clinical mastitis. This difference starts to show up once cows have moved beyond peak lactation – six to eight weeks after calving – and remains until the end of lactation. But commercial dairy farms have shown it’s possible to supply high-quality, low-SCC milk with AOD milking.”
Prof Holmes explains the disadvantages of OAD milking with cows selected for TAD milking include lower milk yield, although the milk has higher fat and protein levels. Milk SCCs are increased and the milk also has a lower lactose level. Clinical mastitis may also be more resistant to treatment.
OAD success stories and the OAD survey
Prof Holmes refers to the first OAD farmers in New Zealand, Lionel Harding and his family who started with the system in 1985.
“They’re achieving an average of 230kg to 265kg of milk solids (kgMS) per cow per lactation and 700kgMS to 760kgMS per hectare. Their herd’s average SCC is 150 000/mâ„“ to 170 000/mâ„“, with a small group of high-SCC cows milked separately. The cows have good body condition and fertility, with no cases of lameness despite long walks between pasture and milking parlour. Most farmers laughed at the Hardings in the early years, but now they’re considered pioneers,” Prof Holmes says.
He reports that on-farm experiments have shown OAD cows have shorter anoestrous intervals after calving and/or require fewer controlled internal drug release (CIDR) treatments than TAD cows. OAD cows also have higher rates of conception during weeks one to three of mating and they conceive earlier. Finally, there are fewer empty (non-pregnant) OAD cows on some New Zealand farms than TAD cows.
Results from a survey of OAD milking commercial dairy farms in New Zealand have shown this system has reduced health treatment costs for cows and reduced incidences of milk fever.
Farm expenses, calculated against kilograms of milk solids produced, were reduced by 25% although there was an average 6% decrease in total milk solids production. The financial progress of farms milking OAD was slower than that of TAD milking farms, although for OAD farmers this was less important than for TAD farmers.
Comments from OAD farmers surveyed revealed efficient milking was essential. Dave and Doug Turner of Canterbury, milking 5 300 cows OAD since 2003, said foremilk should be taken from two teats per cow daily, with the teats being alternated every day.
Cows must be milked out every day and upsetting a cow during early lactation must be avoided. Cows must also be fed well in the later stages of lactation to ensure long lactations.
OAD – the way forward
“The perception is that OAD milking is only for lazy farmers,” says Prof Holmes. “But a similar perception existed in the 1960s and 1970s when farmers who stopped stimulating and washing teats before milking were considered lazy. Now most have adopted this method. OAD milking will soon be accepted as a logical development to save on labour and other aspects in low-cost production systems.”
Contact Prof Colin Holmes at e-mail [email protected] or visit www.dairynz.co.nz. |fw
