Successful Calving with ReproRock

July 2013

A new DairyNZ inititative addressing low in-calf rates and empties in Northland

Low 6-week in-calf rates and high empty rates are a problem in many Northland herds and ReproRock is a DairyNZ initiative to help farmers focus on ways of improving herd reproductive performance. Cushla and Matt Smith have had considerable success in reducing both the spread of calving and empty rates by focusing on cow condition at mating and at calving. Regular condition scoring, once-a-day milking for 1st and 2nd calvers; and regular monitoring of pasture covers and building up pasture covers prior to calving have enabled them to achieve this while increasing production.

The Smiths equity manage a 195ha/450 cow dairy farm at Mangawhai, production system 2, with all young stock grazed off. The herd is predominantly Friesian and Friesian cross. Production is expected to be around 410kgMS/cow this year, slightly up on last season.

Despite the drought Cushla expects they will dry off the herd in late April/early May. “We are comfortable with the feed we have to take us through to the end of April. We made more than 200 tonnes of silage and harvested 220 tonnes of maize, and we’ve bought in about 210 tonnes of palm kernel,” she says.

Calving date and cow fertility has been a concern since the couple took over the farm in the 09/10 season. They cobbled a herd together from five different sources and most cows calved later than the optimum date for Northland. “We had a calving spread of about 20 weeks and it started around 15th July, which is quite late for here, so we wanted to bring the calving date forward and tighten up the spread. The only way to do that was to ensure that the cows cycled as soon as possible after calving, which meant making sure that they kept their condition so that they had energy and they were healthy and happy,” says Cushla.

“So the first couple of years we had mainly older cows aged four years plus. The first year we had a bad drought so we put about 150 cows on once-a-day and had a long mating period, but as time has gone on we have reduced from a mating of 16 weeks using AI plus bulls down to 10 weeks now of AI only.”

“We have also brought our calving date forward almost 3 weeks. The starting date for the coming season is 26 June.”

In the last two years the Smith’s herd has had empty rates 5% above the industry targets but the six-week in-calf rate has improved and the empties have been mainly the older cows that have been culled and sold off.

The younger ones successfully got in calf early with only 7% empties from only 10 weeks of AI and this is the result of the policy of milking all first and second calvers once a day.

“OAD milking means that we are not requiring the energy output from them in terms of walking and milk production. But in saying that, our production has gone up every year for the last three years so milking them once a day hasn’t had a negative impact on production,” says Cushla.

“The reason we got involved with ReproRock was because if you keep young stock in the main herd it is pretty easy to lose your two and three-year-olds. They tend to get bullied, don’t get in-calf as easy and are therefore culled, so you can get a lot of wastage if you are not careful. Our focus was really on the younger animals to ensure that they stayed through to 5 and 6-year-olds when they are really going to produce milk.”

Asked to list the key things the couple has done to improve herd performance, Matt and Cushla came up with the following:

• Calving pattern – ensuring the cows have all calved a week or two prior to the start of mating so they get a chance to cycle during the first round of mating. If calving drags out they are calving into the mating period so they don’t get as many cycles to get in calf.

• Heifer management – growing the young stock to their full potential before they come into the herd, and maintaining their condition once they have calved.

• Once-a-day milking for young stock is a system that we like because the young stock hold their condition and you get the days-in-milk out of them. It’s a system that works for us because we have the people to manage it. A two-mob system for a small herd may not work so well because you have to have an extra person to go and get the second mob in.

• Heat detection is very important for us because we are using AI only and relying on ourselves, not bulls.

• Dealing with non-cyclers – we CIDR any that are 42 days plus from calving and haven’t cycled and if they are cows we want to keep to milk the next year. The number of CIDR’s has dropped every year so that is improving

• Cow health and nutrition – ensuring that there is sufficient quality and quantity of feed for them from calving to mating. We still need to be feeding them well through the low-growth winter months, and so having a feeding plan is essential.

James Muwunganirwa, DairyNZ consulting officer for Lower Northland, agrees that the Smiths use of OAD milking is an excellent strategy. “OAD is a key step in managing the condition of their first and second calvers, and that has worked very well for them,” says James.

“Another important factor is the way they have gone about managing feed – they have very good systems around pasture monitoring, they walk the farm every fortnight and do feed budgeting as well. That enables them to identify surpluses in spring as they arise, and also indicates when they should be stop feeding supplements. It also helps in dry periods and droughts to quantify the feed deficit and thus how much feed they should be bringing in. That is probably the most important thing that they have done with their management systems.”

James says that to optimise reproductive performance, farmers should aim to reach the following targets by calving time:

• Achieving the body condition score of 5.0 for mixed age cows and 5.5 first and second calvers.

• An average pasture cover of not less than 2300kgDM/ha

• Having a spring grazing rotation planner.

Much of the country has experienced a severe drought, so in the wake of that what should be done to ensure that those targets are met? James advises continuing body condition scoring every fortnight until the cows calve.  “Based on the condition score you must adjust their feeding as necessary so that they can achieve the target condition score by calving. They should be drafted into at least two mobs, the skinny ones and the fat ones. The fat mob gets maintenance, and they are often grazed off. That way farmers can keep the skinny ones on the milking platform and ensure they are being fed well enough to put on condition,” says James.

He says to monitor the liveweights of young stock and compare them with target weights. “Most people these days are using LIC’s MINDA Weights software to do that. For most farmers the herd’s reproductive performance is greatly influenced by what happens to the young stock. If they are not at target weight at mating and therefore not at target weight at calving, they are likely not to cycle early and that could result in a number of them not getting back in calf, leading to a lot of wastage.”

He also says to continue fortnightly pasture cover checks and extend the grazing round.   “The aim is to achieve an average pasture cover of 2300 at calving. Continue regular pasture covers and extend the round length. By the time the herd starts calving you would want them to be on an 80 to 100 day grazing round.”

“Monitor the mineral condition of your cattle. Do blood tests and liver biopsies, and administer minerals and vitamins as necessary. Typically there are deficiencies in copper and vitamin B12 at this time of year.”

“Prepare your spring grazing rotation planner. This is one of the useful tools that can be generated on the DairyNZ website, which helps you achieve it easily. The planner tells you what proportion of the farm to be feeding out every day from the start of calving to the “balance date” when the growth of pasture meets the daily feed demand.”