Summer is an ideal time to take stock of your 6-week in-calf rates.
Around the country farmers are improving their herd’s reproductive performance with technology (including the use of collars and sensors), nutrition, and careful monitoring and measurement. The New Zealand dairy sector is on its way to achieving a 6-week in-calf rate of 78%.
As we head into summer, most New Zealand farms will have completed their mating cycle with herds in the early stages of pregnancy.
Achieving successful conception first time around means farmers can enjoy a truncated calving period next spring and ultimately, more days of milk production.
Co-op Programme Manager (Veterinary) Sue Campbell says if farmers want to achieve a 6-week in calf rate of greater than 78%, they need to start thinking about it from the season prior, and particularly the February/March body condition score.
“Planning and organisation is essential. To achieve a higher 6-week in-calf rate, farmers need to be looking at their whole farming practices – young stock management, feed, pasture management, nutrition, animal wellbeing with a preventative approach to disease, support networks, and reproductive tools and techniques.”
Farmers can start thinking about how they can position themselves for calving next season, now. Ensuring cows and heifers are body condition scored over summer and autumn so that they calve down at BCS 5 (cows) and 5.5 (heifers) is key.
Transition management is equally important for setting up cows for good reproductive performance.
“Following on from calving, farmers should be getting the vet out to visit 28 days after the start of calving to metricheck (check for uterine infections) if they have concerns and to set themselves up to get the best 6-week in calf rate. This puts the herd in a good position to cycle pre-mating. More than 80% of the herd needs to be cycling 12 days prior to mating. If farmers don’t achieve this, they will be unlikely to get a good 6-week in calf rate,” Sue says.
Non-cyclers must then be treated early to get the best return on investment – 10 days prior to the planned start of mating for cows that have been calved at least 30 days. Non-cycler treatments include hormonal support such as controlled internal drug release devices (CIDRs).
“Non-cycling issues need to be addressed ahead of mating for best returns and maximising days in milk, which generally pays for the cost of treatment. It pays to assess why some cows are not cycling so those issues can be addressed in the coming seasons – what body condition score did they calve at? What body condition are they at now? Are they having their energy needs met, accounting for feed wastage? How did they transition?”
“Pasture management needs to be on-point”
Over summer, pasture tends to lose its nutritional value as it goes to seed – particularly in the North Island without irrigation – and the metabolisable energy (ME) wanes. Maintaining pasture quality for as long as possible is essential.
“For some South Island farms, irrigation means you can have more control over the situation. In the North Island, however, it is far more challenging and your pasture management has to be on-point. Cows cannot eat enough stalky pasture when the ME drops meaning they are in an energy deficit,” says Sue.
Keep an eye on your heifers
Heifers must be regularly monitored- and summer is no exception. As Sue points out, “anything that takes away from that heifer’s ability to grow as a calf and grow as a heifer will have a negative impact on her whole of life performance.”
Cows continue to grow up until the age of five. If they do not receive adequate care and nutrition over this time, it will likely show in their reproductive performance.
“If a farm finds the reproductive performance of their three-year-old heifers is not where it needs to be, it’s likely because they have not been fed adequately. A relatively common cause of this is having three-year-olds competing with older cows who tend to muscle them out. Farmers need to keep an eye on their heifers and have a process in place to make sure they are getting the best nutrition – either running a separate mob where they can leave higher residuals, potentially milking them once a day to reduce their energy demands or feeding them additional concentrate,” Sue says.
Getting the most out of technology
Marlborough Co-op farmers Tania Riddington and Tim Murdoch have used monitoring collars for the past six seasons and have found their 6-week in-calf rates have been so consistent that they were able to remove bulls from their mating process.
“With the collars we’ve been able to be more hands on with the cows and assess when they are cycling with a high degree of accuracy. For the past few seasons we’ve consistently achieved a mid-70s 6-week in-calf rate. We are AI all the way now and have eliminated bulls from the system,” Tania says.
