6 Tips for success

Read our monthly 6 tips newsletters, designed to give insights around reproduction in dairy farming businesses. These handy and timely tips include anything from reminders to new discoveries.

Heat detection plan

Prior to mating starting, make a plan for heat detection. Communicate with your team so everyone knows who does what, and when. Include procedures for:

  1. Identifying which cows are on heat (paddock checks, heat detection aids)
  2. Managing cows on heat (recording pre-mating heats and drafting for mating)
  3. Which of the drafted cows you’ll mate
  4. Actions taken for cows not cycling

The InCalf book has more detail around heat detection (Chapter 13).

Refreshing heat detection skills

Good heat detection can have a major impact on the overall herd’s reproductive performance. Common mistakes made when detecting heat include missing heats and inventing heats. Minimising missed heats can result in a better calving spread the following year and more days in milk. Minimising invented heats may mean a lower cost per pregnancy and avoid the risk of disturbing a pregnancy.

Review your heat detection skills on your farm - does everyone know exactly what to look for?

Dairy NZ has a handy heat detection skills checklist on their website.

Pre-mating heats

Starting heat detection early can give you an idea of which cows are cycling before the mating start date and can also be an early indicator of submission rate. Target 85% of cows cycling before the start of mating. It takes at least three weeks to identify cows not cycling prior to mating - so get onto this early.

Read more about the benefits of identifying pre-mating heats on the Dairy NZ website.

Identifying at-risk cows

Risk factors for cows becoming non-cyclers include:

  • Later calving cows
  • First-calving cows (Heifers) which were below target weight at calving
  • Younger cows
  • Cows in low body condition score at calving or those which have lost significant body condition after calving (more than 1 condition score)
  • Cows which had an assisted calving, twins or uterine infections

If recorded in MINDA, these cows will appear in the ‘at-risk’ tab in the reproduction section.

Read more about identifying at-risk cows here, and in your InCalf book (page 147).

Managing at-risk cows

The earlier you identify your at-risk cows, the more time you’ll have to decide what to do with them. If you leave it too close to mating you’ll have no other option but hormonal treatment.

One option to consider is to run the at-risk cows separately to the main mob. Separating the at-risk cows from the main mob gives the option to implement preferential feeding or once-a-day milking, which may give cows a greater chance of cycling before mating.

Read more about managing at-risk cows and non-cyclers on our website. If you have a high proportion of at-risk cows, talk to your vet/rural professional about a management plan.

Treating the non-cycling cows

When it comes to non-cyclers you need to have an answer to these three questions:

  1. Are you going to treat/preferentially manage your non-cyclers?
  2. If you are, when and how are you going to treat them?
  • Earlier treatment will likely have a greater impact on the 6-week in-calf rate and not-in-calf rate. Treatments options include hormonal intervention, supplementary feeding and once-a-day milking.
  1. Which cows are you going to treat?
  • You don’t need to treat all cows in the non-cycler group. You need to ask yourself - is it worth treating the old cows, late calving cows or poor producers?

If you are going to treat, talk to your vet/rural professional well in advance to nail down your plans.

Finally, just a note with bulls arriving on your farm, make sure you accept your NAIT movements for any arriving animals. Best wishes from the Repro Team for the upcoming mating period.

For more information or help with your heat detection, contact your local rural professional or InCalf advisor.

Ensure yearling heifers meet liveweight targets

Studies show that heifers which meet liveweight targets at mating get in-calf faster, produce more, and are more likely to get in-calf early in the following season. Regularly weigh and actively manage those that need extra attention to help ensure your yearlings will be at target weight for mating.

Consider mating yearlings ahead of the herd

First calvers take, on average, 10 days longer to resume cycling after calving than a mature cow does.  To help give the first calvers the extra time they need to resume cycling ahead of mating, consider mating your yearlings 7-10 days ahead of the herd.

AB on yearlings?

If you haven’t already, you need to decide ASAP whether you will be doing any AB on your yearlings.  Your yearlings are generally the highest genetic merit animals in your herd, so mating them to AB speeds up your rate of genetic gain.  Check out DairyNZ’s Heifer mating page to see if doing AB on your yearlings is right for you.  If you are going to do AB on your yearlings, ensure you have selected appropriate sires, ensure everyone involved (e.g. AB technician/company, vet, farm staff etc.) is aware that yearlings will be AB’d (and when), and that you have the appropriate facilities available to do the AB in.

Natural mating bulls – numbers & selection

You’ll need one yearling bull per 20 yearling heifers, and a couple of spares in case of injuries or lameness.  If you intend to synchronise heifers for AB, the demand on bull power increases significantly over a short period of time when they return to heat. You’ll need to either double your bull power or reintroduce AB for a short period of time to cover the returns.  Make sure bulls you select are well grown, sound, fully vaccinated, and are BVD etc. free.  Also keep in mind size - smaller, younger bulls are less likely to injure your girls as they mount.  For more info on bull selection, check out our bull buying and leasing checklist.

Organise natural mating bulls early

Get the bulls on farm well before they are due in the paddock – at least 2 months before mating is due to start.  This gives them time to get used to you, your farm, and to establish their hierarchies before they’re out with your heifers.  Watch for overly dominant or aggressive bulls, as they may be problematic and cause injuries to each other, you, or your heifers. If there are aggressive bulls, send them back or to the works.  If you mate your yearling heifers ahead of the herd, remember that your bulls will need to arrive on farm even earlier.

Once the bulls are on farm

Once the bulls have arrived, there are 3 key things you need to do:

  • Check for any injuries that may have happened during transport
  • If there are any, address them immediately or request a replacement bull
  • Quarantine them for 10 days and observe for any signs disease or walking defects
  • Trim hooves if necessary.

For more information or help with your yearling mating, contact your local rural professional or InCalf advisor.

Keep monitoring and managing yearlings and R2’s

This is the time of year that we usually see heifer weights dip below the MINDA Weights guideline. This generally isn’t a problem as long as you keep the girls’ weights to within 10% of the guideline.  However, Steve Forsman, our resident Heifer guru, has recently seen several people caught out by low heifer weights due to not regularly weighing and monitoring their heifers. Regularly weigh and actively manage those that need extra attention to avoid a nasty surprise with your heifer weights.

Rising 2 year olds

The liveweight and BCS that your R2’s/first calvers will calve at is pretty much set by now.  If you know your R2’s are going to calve at sub-optimal liveweight and/or BCS, make a plan now for how you are going to give these girls the best chance at getting back in-calf early at mating time.  This could include putting them on once-a-day for all or part of the time leading up to and through mating, or having them in their own herd so they don’t have to compete with older cows.  Talk to your rural adviser to nail down your plan.

Are you ready for calves?

Take some time now to ensure you and your team are ready for the arrival of calves, especially if you have some added beef crosses to keep as well and for longer than usual.  For a refresher on the key points around calf rearing, check out DairyNZ’s calf care page.  Also, check that you have established procedures for calf collection, recording, feeding, handling sick calves, and euthanasia.  Making sure that everyone knows what they need to do and when will help to avoid poor decision making when you’re all feeling knackered.

Is your calf shed ready?

Without the presence of the mother and with low antibodies, the calf sheds need to be sheltered from extreme weather conditions as well as dry, disinfected and well ventilated to give calves the best start possible.  Make sure your calf shed will meet calves’ shelter, bedding, and water requirements.  In addition, check whether you have got enough tags, feeders, teats, iodine, cleaning products, bedding, water troughs, meal troughs and hay.

Colostrum: the liquid white-gold of calf success

Calves that don’t receive enough quality colostrum within the first 6-12 hours of life are more susceptible to disease and death, along with having lower weight gains, putting your girls on the back-foot right from the start.  Calves need 4-6 litres of colostrum in the first 12 hours, and first day colostrum is essential.  Make sure your farm has a plan that ensures every calf will get all the quality colostrum she needs.

Healthy calves become healthy cows

Mortality rates can soar quickly in unsuitable sheds, which makes keeping on top of calf shed sanitation critical. Talk to your veterinarian about the best products to use.  In addition, sick calves generally don’t grow as well as healthy calves.  Have your calf health monitoring plan handy in the shed and ensure your staff know how to spot and treat common illnesses to help reduce the number of sick calves you have this year.  Also, ensure you and your staff know what to record so that that all calf treatment plans are carried out fully and correctly.

For more information or help with your young stock, contact your local rural professional.

Continued increase in detailed reproduction data

The number of herds with a detailed Fertility Focus Report has increased to 4430 (55%) out of the 8092 LIC customers that produce a seasonal calving Fertility Focus Report. This is up from 52% in 2018 and 48% in 2017.  This trend shows that more and more farmers are recognising the importance of having detailed reproduction data so that they can make informed herd management decisions.

National average 6-week in-calf rate

Good news!  We have hit our highest ever national average 6-week in-calf rate - 68%.  The national average has been climbing for the last 3 seasons, a fantastic turnaround from the previous 3 seasons.

National average 6-week in-calf rate

National average not-in-calf rate

More good news!  This season the national average not-in-calf rate was just 15.6% for a 10.7 week mating.  We haven’t had a not-in-calf rate this low since 2014!  But even better, we achieved this result with a shorter mating length (2014 = 78 days, 2019 = 75 days).

National average not-in-calf rate

Improving results means more money

Comparing this season’s results with results from Spring 2016, the average herd reported (537 cow farm) is now pulling in nearly $11,000* more as a result of the improved reproduction results.

All AB (No Bull) herd results

Around 10% of herds (464 herds) were All AB for the 2019 spring mating.  The All AB herds had an average 6-week in-calf rate of 69.3%, 1.6% higher than AB + natural mating bull herds.  This is consistent with the results we have seen for previous seasons.  Also consistent is the 0.9% higher not-in-calf rates for the All AB herds.  These results reinforce the fact that doing All AB is a viable mating option, but as always, we advise you to consult with your reproduction expert to see if going All AB is, indeed, a sensible option for you.

All AB results 2019

Top honours

As is the case each season, there isn’t much difference in the results between the regions.  This year, the region with the highest average 6-week in-calf rate is Waikato!**  Waikato beat out last year’s winner, Taranaki, by 0.1% with an average 6-week in-calf rate of 69.2%.

*This figure was calculated using the DairyNZ InCalf gap calculator. 6-week in-calf rate gap: 537 cows x $4 x 2% increase in 6-week in-calf rate = $4,296.  Not-in-calf rate gap: 537 cows x $10 x 1.2% decrease in not-in-calf rate = $6,444.  Total combined increase in profit: $4,296 + $4,296 = $10,740.

**Regions with less than 50 herds were excluded from this analysis.

Communicate with your herd’s winter grazier

Finding out what the situation is at your grazier’s property is a worthwhile reason for a phone call. Weather has played havoc in many parts of the country, so having a clear understanding on whether extra feed needs to be arranged before cows leave your farm is essential. It’s also important to have clear communication on arrival dates for mobs so there are no surprises for you or your grazier.

Have a transition management plan

Many graziers will be using crop to feed your cows. Have a robust and efficient transition management plan in place, for transition onto and off the crop, to help avoid cow health issues.  There is no ‘almost getting it right’ in this case as the consequences are often severe.  For more information on crop transition management check out these dairy NZ resources on fodder beet and brassicas.

Fodder beet research

In recent years some famers have become concerned about the potential health effects on their cows grazing on fodder beet.  Recent research by DairyNZ into fodder beet has identified that fodder beet should not make up more than 30% of lactating cows’ diet and 60% for non-lactating cows.  For more information, see DairyNZ’s article on fodder beet.

R1’s and R2’s

It’s also worthwhile giving your young stock grazier a call.  Your heifers will be heading into winter soon, and historically winter is a time where heifers fall behind target.  A timely discussion about the quantity and quality of heifer feed intake, backed up by weight data, will assist in identifying the size of any potential winter feed deficit.  If it looks like extra feed will be needed, make sure you nail down who will be supplying the extra feed and what type of feed needs to be supplied.

Don't just weigh your heifers

Weighing heifers doesn’t make them heavier, but using their weight information can help to direct your efforts. Use ‘Manage animals’ in MINDA® weights to identify animals slipping into the “Action” group. Click on the “Action” group to view their birth ID and how far behind ideal liveweight they are.

Spread your knowledge

There is a large amount of valuable knowledge and information stored away in experienced farmers minds - consider sharing your knowledge in some training sessions for any junior staff before the well-deserved breaks begin. Ask them what they’d like to learn and do targeted training given time is precious.

Time to review

If you’ve got early aged pregnancy test results for the whole herd, now’s the time to head to the Reproduction section on MINDA Live to look over your herds results.  There’s 3 things you are looking for:

  • Trends over time – have your results improved or dropped over the last few seasons?
  • Periods of time that went well/not well – is there a period of time that your in-calf rate jumps up or slows down?  What was happening on farm at that point in time?
  • Groups of cows going well/not well – is there a group of cows that did not perform as well as expected?  E.g. first calvers 6-week in-calf rate is lower than the 4-8 year olds.

Assessing these 3 will help you identify what’s going well, better or worse or the same as last season and which of the 8 Key Management areas you need to focus on to lift your herds reproductive performance.

Protect next seasons success

Protect next seasons mating success by starting to work towards calving body condition score (BCS) targets now (BCS 5.5 for 2 & 3 year olds, 5 for mature cows).  Cows at different body conditions require different management.  After you’ve scored the cows, draft out a lighter mob so you can cater specifically to their needs and ensure cows are getting the treatment they need to reach target.  This may include once-a-day milking or drying-off.

Staggered drying-off

Dry off cows in groups based on BCS, calving date, and age (younger cows first).  It takes dry cows approximately 2 months to gain 1 condition score, and cows generally don’t gain condition for 1-2 weeks after drying-off or in the last month before calving.  This means that cows that are due to calve in early July that need to gain more than 1 BCS need to be dried of right now.  You may also wish to selectively dry off some high somatic cell count cows earlier to protect your bulk milk somatic cell count towards the end of the season as milk volumes drop.  Check out DairyNZ’s BCS strategies page for more information staggered drying-off.

Drying-off guide

The drying off guide on MINDA Live will help you to get a list of cows to dry-off (Reporting tab -> End of Season box -> Drying off guide).  The report gets you to choose your dry-off criteria, then it gives you a list of cows that meet those criteria.  You also choose how important each criteria is so that the dry-off guide can put those who meet your most important criteria at the top of the list.  For example, if your most important criteria is drying off your young cows that will calve early, an R3 early calver will be higher on the list than a 5 year old early calver.

Cull cows

For many regions it’s very dry and feed is in very short supply and it is important to not compromise on the APC targets for winter.  Culling cows that won’t be on farm next year (empty or other culls) is an effective way to help manage feed demand on farm.  Culling low producing and/or high somatic cell count cows will help divert feed into the cows that are producing milk more efficiently for you.

Culling guide

The Culling guide on MINDA Live will help you to get a list of cows to cull (Reporting tab -> End of Season box -> Culling guide).  Like the Drying off guide, this report gets you to choose your culling criteria and the importance of each criteria, and will provide you with a list of potential cows to cull.

What went well this season?

Things don’t always go to plan on-farm, but take some time with your team to find a few gems from this season. Maybe the herd has a higher 6-week in-calf rate this season - early indications from the national results are that results are slightly better this year (hooray!).  Maybe you had fewer mastitis problems this year.  Or maybe the tractor and fence have not had as many close encounters this year.  Whatever the successes, celebrate them to help everyone head into next season in a positive mind-set.

Ideas for next season

Throughout the season you will have come across things that you’d like to do differently next season.  Write them down and work with your team to make a plan of how you will tackle the situation differently next season.  Working on plans together helps keep everyone in the loop and take ownership of executing the plan.

New staff and staff training

The dry period is a good time to welcome new staff and get them familiar with the way your farm runs.  It’s also a good time to complete some staff training.  Having everyone on the same page and lifting staff skill levels ahead of calving may help to prevent mistakes during calving that could impact on herd reproduction, e.g. being unable to correctly identify, treat/manage and record sick cows.

Calving planning

Plan the spring transition period now as it is the riskiest time of year for cows when most metabolic and infectious diseases occur.  Well-transitioned cows have fewer uterine infections, reduced chance and severity of mastitis, and increased milk production through better health.

Safeguard pregnancies

Reduce the risk of abortions by ensuring your cows and first calvers don’t have access to macrocarpa, pine needles, or mouldy silage, as all can cause abortions.  In addition, excessive nitrates in feed can kill both cow and calf.  Avoid abortions and cow deaths by talking to your vet about strategies to safeguard cows and pregnancies.

Farming during COVID-19

The DairyNZ website has a Coronavirus page with lots of information and resources to help you and your team farm safely through this challenging time.

Keep your heifers on track for this period

It is good practice to weigh your heifers every 4 to 8 weeks. Through summer it is critical to follow this guide as this is a risk period for R1’s and R2’s falling behind their weight targets.  The more often you weigh them, the better placed you are to make proactive decisions to mitigate risks and minimise the damage. MINDA Weights can help you track the group and identify individuals that are at risk of, or already are falling behind.

Supplementary feed for young stock

Whether you graze your heifers at home or they are out with a grazier, you need to plan for the times when the feed starts to run short by asking yourself some important questions:

  • What supplements will you have available for your heifers?
  • How are you or your grazier going to feed them these supplements? 
  • Will you or your grazier decide when supplementary feed will be fed out?

Once you have made a plan, make sure you communicate it to everyone involved to ensure it is carried out.

Scrutinize your calves

You may be in the beneficial position where you have more calves/R1’s than you need.  Carefully consider - do you want, or need, to keep all of them?  For your tail-enders, are you better to cut your losses on them now and put the feed and other resources into your better calves?

Heifer animal health plan

Animal health plans need to be specific to the farm where the heifers are grazing as disease exposure, parasite presence, mineral deficiencies and bio-security risk vary on each farm.  Monitor relevant eczema levels if your heifers aren’t local and have a plan in place to prevent eczema.  Also consider and plan any oral or pour on drenches needed to keep animals in the best possible condition.  Talk to your vet to help ensure your heifer animal health plan checks all the right boxes.

Maintaining herd Body Condition Scoring (BCS)

Stay on top of your herd’s BCS throughout summer to help get them to their calving BCS easier in autumn.  Check out the DairyNZ Summer Strategies page and our How to maintain BCS over summer article for tips on keeping your herd’s BCS on track.

Feeling the heat

Throughout the country, cows will be experiencing varying levels of heat stress this summer.  When the temperature is more than 21ºC and relative humidity is more than 70%, Friesian’s and crossbreeds begin to reduce their feed intake, and milk production is reduced*. Jerseys are more tolerant of heat, with production losses insignificant until 25ºC*.  Sustained periods of reduced feed intake could lead to BCS loss, so check out DairyNZ’s heat stress page for tips on how to reduce your herd’s heat stress.


*J. R. Bryant , N. López‐Villalobos , J. E. Pryce , C. W. Holmes & D. L. Johnson. (2007). Quantifying the effect of thermal environment on production traits in three breeds of dairy cattle in New Zealand. New Zealand Journal of Agricultural Research, 50, 327-338. doi.org/10.1080/00288230709510301

Herd nutrition through to the end of mating

It is common to see in-calf rates drop off after week 6 of mating.  This tends to coincide with a drop in feed availability and/or a drop in feed quality.  Because cows that are experiencing a feed restriction tend to be less likely to display heat behaviours when they’re in heat*, suboptimal herd nutrition will make it harder for you or your bulls to find the cows that are in heat.  

Pages 88 and 89 of the InCalf book (DairyNZ Ltd, 2017) have tips on monitoring your herd’s nutrition, and DairyNZ’s summer management page has information on managing feed through summer.

Book your scanning dates

To get an accurate picture of how mating has gone this year, you need at least 80% of your herd to have an early aged pregnancy test result.  

To get early aged pregnancy test results, cows must be scanned between 35 and 122 days of pregnancy.  

You can use our when to scan calculator to see when you will need to scan to get early aged results for your cows.  

Book in your pregnancy testing now to ensure you get the scanning date you need to get early aged results.

Hitting BCS targets

To help your cows get in-calf early next mating, they need to reach their target calving BCS – helping them hit this target starts this summer.  

Even with exceptional feeding, dry cows rarely gain more than 0.5 BCS units in a month, so it’s important to maintain BCS through summer so that autumn’s job of getting your cows to calving BCS target doesn’t become impossible.  

Your farm system will dictate what options are open to you, such as once-a-day milking and drying-off selected cows early.

Monitor and manage BCS

Monthly body condition scoring will allow you to keep tabs on BCS.  Regular scoring will allow you to actively manage BCS throughout summer.  

In terms of farm system efficiency, maintaining condition is more efficient than losing it and regaining it later.  

The aim is to keep 85% of the herd above BCS 4.0 throughout summer.  Using a BCS-accredited professional will help you to maintain objectivity.

Remove culls

Empty cows do not milk better than pregnant cows - research** with twin cows in New Zealand shows that empty cows did not milk better than their pregnant twin until 250 days of lactation, and the differences were small. 

To help ensure your herd continues to get the feed it needs to maintain BCS through summer, remove your cull cows from your farm so that you can put your feed in to the cows you are going to keep.

Heifer update

Over the last few years we’ve made great gains in getting our heifers to target liveweight at 3 and 15 months.  

The graph below shows the improvement in the quality of heifers being handed over for rearing at three months of age – they are, on average, 3% above the MINDA-Weights guideline for this age.  

Heifer live weights

We are now also getting our 15 month old heifers, on average, to 1% above target. 

Unfortunately we are falling short of the mark after the heifers become pregnant at 15 months old, as they are entering the herd as R2’s/first calvers 4% below target (on average).  

This means that they are getting in-calf fast at 15 months old, which leads them having a tight calving pattern as first calvers, but they’re not getting back in-calf as fast or milking as well as expected once in the milking herd.

We often see heifers starting to fall behind weight targets in summer, so regularly weighing your heifers through this period will help you or your grazier to act quickly if liveweights drop below target.  Dairy NZ has more detailed information on nutritional requirements of heifers.

Reduce heat detection fatigue

Doing heat detection over a long period of time is a challenge for anyone.  But missing heats will impact this year’s reproduction results, next year’s milk production and the ability of your herd to get back in-calf next year.  

To help reduce the risk of heat detection fatigue:

  • Share the load – either have someone else help with the heat detection duties, or lighten the heat detector’s load so they are able to put a renewed focus on the task at hand
  • Consider putting on a second heat detection aid part way through mating.  Another aid may help to pick up cows that are not showing heat well and help maintain good rates of detection.
  • If there’s a team of staff sharing the heat detection duties, ensure that communication is still working well between the team and that procedures (such as who records what and where) are still being followed.

Bull management risk assessment

To help get the most out of your natural mating period, make sure that your bull management is top notch. 

InCalf’s Bull Management Tool has a quick risk assessment you can do to see if the way you’re managing your bulls is potentially impacting your herd’s reproductive performance.  

DairyNZ’s Bull Management page has more information on successfully managing your bulls.

Monitor bull body condition score (BCS)

Bulls need to start the mating season with a BCS of 4.5–5.5 and be fed appropriately to maintain this. 

Bulls that are below or above this BCS commonly have lower fertility (DairyNZ, n.d.).  Monitor and pro-actively manage your bulls’ BCS to help maintain their fertility.

Manage herd nutrition during natural mating period

We often see a drop in in-calf rates during the natural mating period.  Bull numbers and/or management can be a part of the reason for this, but another factor, often underestimated, is herd nutrition. 

Cows that are experiencing a feed restriction tend to be less likely to show when they are in heat (Burke et al., 2010).  This restriction could either be a lack of feed availability, or a drop in the quality/ metabolisable energy of the feed being offered, or a combination of both.

Whilst bulls have more tools than us for detecting when a cow is in heat, cows that are showing only weak signs, or no signs of heat will make his job harder, if not impossible.  

Help your bulls find who’s in heat by ensuring your herd’s nutrition stays on track the whole way through mating.  Check out pages 88 and 89 of the InCalf book for tips to do this (DairyNZ Ltd, 2017).

Mating length decisions

Nationally mating length has been decreasing over the last few seasons.  Compared to 2012, the average mating length has been shortened by 10 days to be just under 11 weeks long.  

There are many valid reasons for changing mating length, but if you’re thinking of shortening your herd’s mating length, keep in mind the impact that change will have on your not-in-calf rate/how many empties you’ll have.  

Table 1 in the InCalf Length of Mating Period Tool shows that shortening your mating length by 1 week can increase your not-in-calf rate by 1% to 4%.

If a higher not-in-calf rate is not an option for you, but you still want to reduce your herd calving length, an option is to use short gestation length (SGL) AB sires at the end of mating.  

Alternatively, some farmers are using SGL to extend their mating length to reduce their not-in-calf rate whilst still maintaining the same herd calving length.

Monitor heifer mating

As many heifers are not on farm for their 15 month old mating, it may be easy for it to be “out of sight, out of mind”.  These girls are generally your best genetics and the future of your herd, so making sure they get in-calf and enter your herd is critical.  

Keep in touch with whoever is managing your heifers’ mating throughout mating.  Regular communication will allow you to be proactive if things are not going well, and help ensure they follow best practice to help your heifers get in-calf well.  Many of the tips above also apply to heifer mating management.

Monitor milk dockets

Monitoring milk dockets is a good way to keep an eye on your herd’s nutritional status during mating as energy status can impact a cow’s ability to show signs of heat and get in calf (Burke et al., 2010). Keep an eye on milk solid yield and milk composition (DairyNZ Ltd, 2017).

If milk solid yield drops by more than 0.07 - 0.1 kgMS/cow/day over 2-4 days (be sure to account for differences in cow numbers, milking times and calf milk):

  • Pasture quality may have declined
  • Consider increasing energy intake through increasing supplementary feeding or pasture allocation 
  • Check cows have sufficient access to drinking water
  • Review grazing management, daily feed allocation and residuals

If 10-day averages of milk protein percentage drops or is lower than the previous year’s result:

  • Consider increasing energy intake through increasing supplementary feeding or pasture allocation 
  • Review grazing management, daily feed allocation and residuals

Check out chapter 11 of the InCalf Book for further suggestions (DairyNZ Ltd, 2017).

Monitor short returns

A cow has an oestrous cycle every 18-24 days (with only the odd exception having a true heat outside of this time period). We can therefore keep an eye on heat detection by monitoring the number of cows that have returned to heat between day one and 17 or day 24 onward, classing heats as missed or invented. In the first 17 days of mating, keeping an eye on the early indicator graph in MINDA Live reproduction is a good measure as to how heat detection is going, alerting you to how many short returns have occurred. 

Consider reviewing heat detection practices when short returns exceed 10%. After day 35 of mating the return interval analysis in MINDA Live will show the portion of returns that are short, normal and long. Industry target is to have fewer than 13% short returns.

Monitor submission rates

Three weeks (the length of one oestrous cycle) of mating is enough time for most of the cows within your herd to have cycled once. Therefore the industry target for the number of cows submitted in this time is 90%. In order to reach this target there will be roughly 4% of cows detected on heat and submitted daily.

MINDA Live is populated daily with submission rates and is something that you can monitor in the first three weeks to keep an eye on how you are tracking. Drops in the proportion of cows submitted daily, can indicate issues before it’s too late.

Monitor cow condition

A drop of more than 1 BCS (Body Condition Score) between calving and mating will likely impact submission and conception rates negatively.

Regular checks and staying on top of this will give your cows a better opportunity to get in calf. The target BCS for start of mating is 4.5 for 2-3 year olds and 4 for 4+ year olds.

Monitor natural mating bulls

The number of bulls required will depend on the number of cows likely to not be pregnant. Check out Dairy NZ guidelines to check that you have enough bull power. It is also important that you get these bulls on farm early so that they can adjust to the new surroundings and feed, reducing the risk of under performance during mating. It is also a good idea to split them into two mobs and rotate those teams so they get a rest and avoid fatigue, keeping them in optimum condition.

But most of all, stay safe!

Have a plan B

It’s all very well to monitor the above, but make sure there is a plan of attack if any issues have been indicated through one of the above measures.

Consider your options:

  • Preferentially manage a group of at risk cows
  • Attend a heat detection workshop
  • Extend mating with the use of short gestation semen to get some more cows in-calf without detriment to your calving pattern
  • Talk with your vet about the possibility of intervention – if that is the case, the earlier the better.


Burke, C., Williams, Y., Hofmann, L., Kay, J., Phyn, C., & Meier, S. (2010). Effects of an acute feed restriction at the onset of the seasonal breeding period on reproductive performance and milk production in pasture-grazed dairy cows. Journal of Dairy Science93(3), 1116-1125. doi:10.3168/jds.2009-2562

DairyNZ Ltd. (2017). Body Condition and Nutrition. In The InCalf Book for New Zealand Dairy Farmers (2nd ed.). Retrieved from https://www.dairynz.co.nz/media/5789084/the-incalf-book.pdf

Start early

Apply tail paint early and observe pre-mating heats to give yourself an opportunity to make a decision by understanding what proportion of cows are cycling before your mating start date. You can also use that period to ensure everyone is on the same page as far as identifying which cows are on heat.

Know the importance

Poor heat detection can be very costly to your farming business. The cost of a missed heat can be easily calculated with the following equation:

Repro equation

In addition to the financial cost, there is the belated cost of having a cow calving later than expected, leading to less time to recover and get in-calf early the following season.

Timing is everything

Cows are in a race against time and there is only a small window in which a cow can conceive. A cow comes on heat every 18-24 days for 6-24 hours, with ovulation occurring around 30 hours after the onset of heat. With the national average mating period being 10.8 weeks, this means that, at best, cows mated in the first 2 weeks of mating only get a maximum of 4 chances at getting in-calf. If they are missed or are not cycling by the end of 3 weeks, they might get only 1 or 2 opportunities.

Race against time

Know the odds

Mating a cow that is not on heat has a 0% chance of conception and mating a cow that is already pregnant has a 20-50% chance of disrupting the pregnancy (Sturman, Oltenacu, &Foote, 2000). It is crucial that a good process is in place for picking and drafting cows on heat.

Give them every chance

Although calving patterns are a big predictor of in-calf rates, there are some other things that you can do after calving to improve the chances of getting back in-calf. This includes keeping a close eye on cow health and body condition score and preferentially managing ‘at risk’ animals through once a day milking. Supplementary feeding and treatment will also put your cows in a better position to resume cycling, show strong signs of heat and get in-calf quickly. Studies have shown that cows on restricted feed or in energy deficit will show weaker or no signs of oestrous (Burke et al., 2010).

Have a strategy

Ensure that all farm staff are well informed of the process around mating. Cover off things such as:

  • What heat detection aids will be used?
  • How are the aids applied, interpreted and maintained?
  • What is the process when a cow is recognised as being on heat?
  • What is the process after a cow has been mated?
  • What is each person responsible for?
  • What happens if someone is unavailable (e.g. injury)?

Check out the latest stats

Results are finalised from the 2018 spring mating season and its great news. Nationally we have improved the 6 week in-calf rate by +0.9% and not-in-calf rate by -0.8% from the previous season, building on the gains already made between 2016 and 2017. Keep going at this rate and the 2019/20 season could be the best season on record! Check out our website for the full run down.

6 week in calf rate

Keep up those records

One of the main benefits of having national stats is bench marking. Bench marking gives you the ability to see where an individual farm or group of farms sits in relation to others in similar circumstances and enables accurate goal setting. These national statistics are comprised of data from the 4207 herds across the nation, with a level of recording high enough to obtain a detailed Fertility Focus Report. With this number of farms growing annually, we hope that the national statistics become increasingly reliable and that farmers see the increased benefits of having good records at their fingertips.

Know the measures: Not-in-calf rate

You will notice that officially published reproductive performance statistics will refer to ‘not in-calf rate’ as opposed to ‘empty rate’. This is because the not-in-calf rate is, essentially, everything minus the final in-calf rate making it comparable among farms and good to use for bench marking between years as well; whereas the empty rate can differ from farm to farm depending on who was diagnosed come pregnancy testing time. Nationally the rate of cows recorded empty was 11.8% of eligible cows, however the not-in-calf rate was 16.7%.  The not-in-calf rate includes cows with a doubtful pregnancy testing result, culled before receiving a pregnancy testing result, or missing both a pregnancy testing result and a record of culling. 

Not in calf rate

Consider the repercussions

While it’s fantastic that we’ve improved reproductive performance over the last few years, it’s important to remember that with improvement comes repercussions. More cows in-calf in the first 6 weeks and a lower not-in-calf rate means more calves on the ground earlier and more lactating cows needing to be fed too. Make sure you’re well-resourced to keep up with the energy demands of all these extra mouths and that you have a plan in place for accommodating surplus stock. 

Don't forget the update

2018 saw the update of the Fertility Focus Report to version 3.01. With this update came changes to some of the calculations, such as conception rate. With the national stats being calculated through the output of the DairyNZ Fertility Focus Report and its rules, previously published national stats are not comparable as they will have been the output of the previous 2.15 version. But don’t worry, we have run three seasons worth of data through the new version so that you’re getting the best bench marking data out there. DairyNZ will also be updating the dairy statistics publication to accommodate these updated results!

Think of going all AB

The stats are through on herds that used all-AB through mating compared to herds whom used a combination of AB and natural mating. All-AB herds had a 0.2% higher 6 week in-calf rate but a 1.1% higher not in-calf rate. These were driven by a 3.4% higher 3 week submission rate and a 1.5% lower conception rate for all-AB herds. However, when you account for the fact that conception rates can only be calculated for the AB period of mating, this lower conception rate of all-AB herds makes sense as the longer you get through the mating season, the lower the conception rates are. In other words, the more cows you can get pregnant in the first 4-6 weeks, the more efficient you will be in getting cows in-calf, regardless of using AB or Natural Mating bulls. And really the choice is yours when it comes to deciding to go all AB - national statistics say there’s not much in it.

Have the essentials ready

Prepare a calving kit in advance so you have an opportunity to go and source anything you’re missing. There is no time to be scrambling for essentials during calving! DairyNZ recommends preparing a bucket with:

  • Navel spray
  • Metabolics
  • Lube
  • Towel
  • Soap
  • Calf tags/identification
  • Gloves
  • Notebook and pencil/recording tool
  • Calving ropes
  • Spray paint/tail paint
  • Torch
  • Food/energy bars for staff
  • Calving intervention guide

Get your calf sheds ready

Upon calf collection you need to have calf sheds ready - preparing now can take some stress off. Without the presence of the mother and with low antibodies, the calf sheds need to be sheltered from extreme weather conditions as well as dry, disinfected and well ventilated to give calves the best start.

Colostrum is key

Colostrum is an essential part of the calf’s development and is vital in the first hours of life. Colostrum is rich with antibodies that provide the calf protection from illness in this time.

Get everyone up to speed

As it can get pretty crazy during calving, it is a good idea to take some time now to discuss the key responsibilities and processes around calving with staff. If you don’t have staff, consider hiring and training them up to give you a hand through this period.

Plan for rearing

Start thinking about your heifer rearing process. These animals are the future of your herd and need to be well grown to ensure they become productive in the herd. Farmers use different methods for growing heifers - be it on a run off, at the dairy farm or through a contractor. Either way, thinking about your process in advance will give you more time to make sure they’re under the responsibility of someone that is committed to reaching live weight targets and has good communication.

DairyNZ has some good points to consider when thinking about different rearing options.

Keep your records in order

Recording is the key to making informed decisions in the future, whether that be regarding herd improvement or otherwise. Make sure you have a process in place for recording during calving - you will need to record things such as:

  • Date
  • Fate
  • Dam
  • Sex
  • Calf identity number
  • Assisted or unassisted calving

The MINDA app is a great way to record on the go.

Know the physiological changes

During calving a cow’s immune function is compromised, teat canals open and unfavourable ground conditions are common which increases risk for mastitis rates.

At calving a cow’s pelvic tendons and ligaments relax for ease of calving however this can lead to less stability overall. In addition, a cow’s body condition loss after calving can reduce its foot’s ability to absorb shock and can lead to increased risk of lameness*.

Practice good stockmanship

Good stockmanship during this period can be all the difference. Not rushing stock on the tracks and practicing good hygiene at milking will help minimise risk of infections.

Know the trigger points

It’s important to recognise what a normal level of disease is around calving, so you can identify when to intervene. Look out for any of the following red flags*:

  • More than 5% of the herd require hands-on assistance to calve
  • More than 2% of the herd have retained foetal membranes 24 hours after calving
  • More than 5% of cows become lame in a month
  • More than 5% of the herd have clinical mastitis the month after calving
  • More than 5% of the herd suffer any other health problems at calving or during early lactation

Stay on top of body condition score (BCS)

BCS is a crucial factor in influencing the health of the transition cow, her milk production and reproductive success.

For this time of year it’s important to note that there are around 40 days in the dry period that a cow will not put on condition. For the first two weeks after drying off they will not gain due to the active immune response involved in drying off. They will also gain very little in the last month before calving due to the calf taking over a portion of the rumen capacity in the abdomen as well as the large energy demand the growing calf demands. Make sure this has been factored in when it comes to creating a strategy to reach condition score targets**.

Have a plan

The dry period is a great time to go over strategies with staff. For example, what happens if a cow becomes sick? What is the recording process? What will the different roles be at calving? Preparing your staff can ensure a successful transition period for your herd.

Record, so you can learn from it

Improvement year on year largely hinges on recording. By recording treatments in MINDA® you can analyse the portion of your herd with a health condition and also how it impacted in-calf rates and ultimately not-in-calf rates, allowing you to better identify what the issues are for your herd.



*DairyNZ(2017) Caring for the transition cow. Inside Dairy. June edition

**DairyNZ(2014) Feeding for condition score gain. Technical Series. Issue 21

Aim for BCS targets

Cows that reach calving body condition score (BCS) targets can produce more, begin cycling earlier after calving and therefore be more likely to fall pregnant toward the start of mating.

Body condition score targets at calving are as follows:

  • 2 & 3 year olds              5.5
  • 4 - 8 year olds               5
  • 9+ year olds                  5.5

Condition takes time

Cows will not gain BCS for one to two weeks after dry off due to the immune response involved in the drying off process. They also gain very little right before calving due to large energy demands of growing a calf. All up there are approximately 40 days during the dry period where cows are not gaining condition. This, along with BCS should be taken into account when deciding on dry off dates for your cows.

Don’t overshoot

When it comes to BCS, there is a sweet spot. Although we often refer to at risk cows as those that are under target, cows over target can also be at increased risk of metabolic disease. Make sure you keep monitoring your animals so they don’t end up too far on either side of the scale.

Have a feed plan

Take the guesswork out of feeding for BCS targets by making a feed plan around the type and quantity of feed depending on live weight.

The below table (retrieved from p52 DairyNZ Facts and Figures) shows the amount of feed (kg DM) required to be eaten for a 1.0 increase in body condition score across different feeds and breeds.

Dry Matter Table

Manage individual cows accordingly

Individual cows have individual needs. Separating dry cows into separate mobs based on BCS allows you to more accurately cater to their needs and use feed effectively.

Don’t forget the next generation

Young stock should represent some of the best genetics in your herd. Keep up good communication with your grazier to make sure they reach live weight targets. This will give them the best possible start and a chance to perform to their full potential both productively and reproductively. The below table displays live weight targets for different size cows at different ages (retrieved from p56 DairyNZ Facts and Figures).

Heifer liveweights

With over 4,000 herds across the country now recording enough data to produce detailed fertility focus reports, the latest version features some updated targets.

Get your hands on one

A Fertility Focus Report can be obtained through the MINDA® LIVE reproduction tab under ‘reports’. They can also be obtained through CRV Ambreed and Infovet.

Keep on top of recording to get a 'detailed' report

Depending on the level of data available there are three types of fertility focus reports that can be produced, this is displayed on the reverse side of the report.

A ‘basic’ report is generated when only low levels of information are available. Numbers are calculated from re-calving information and the 6-week in-calf rate is an estimate only.

An ‘intermediate’ report requires calving dates entered and AB information recorded for at least 50% of the cows. If there are fewer than 80% aged pregnancy test results recorded the report remains intermediate. In this report the 6 week in-calf rate is an estimate based on calving and mating information.

A ‘detailed report’ is most accurate and is the best report to use when comparing performance between seasons and farms as well as using to base herd management decisions. To obtain a detailed report at least 80% of the herd must have aged pregnancy results recorded and at least 80% of those results need to be early aged. Check out our when to scan calculator for more information on early aged pregnancy diagnosis.

Know the difference between not in-calf rate and empty rate

You will notice that the Fertility Focus Report displays the ‘not in-calf rate’ as opposed to ‘empty rate’ to measure reproductive performance. This is because it allows reports to be compared to other farms and to previous seasons. Empty rates can be subjective which is why the not in-calf rate is used. This figure is 100% minus your total in-calf rate, this means it includes culls, rechecks and animals that were not tested.

Understand how to follow the report

The Fertility Focus Report displays a lot of information on one page. Make sure you take the time to get acquainted and understand how to follow it through in a logical progression.

The first section gives an overview of the herd reproductive performance, looking at key reproductive measures. The second section shows how the key measures in the first section were obtained, displaying the drivers of the 6 week in-calf rate. The third section then looks at performance in some of the key farm management areas that impact reproductive performance so you can gain insights on what management areas (such as calving pattern, heat detection, young stock management or bull management) are positively or negatively impacting reproductive performance.

If you are having trouble following the Fertility Focus Report speak to a trained in-calf advisor or trusted rural professional, or download the Fertility Focus user’s guide.

Set goals

With the Fertility Focus Report allowing you to track the progression of reproductive performance over years and compare to targets, it makes it easy to set reasonable goals. The aim above targets and star rating system is based off actual farmer data. Top results and aim above targets are set at performance achieved by the top 25% of farmers.

Discuss it with a rural professional

The Fertility Focus Report is a great conversation starter, talk it through with you rural professional and together come up with an action plan that works towards your goals.

For more information or help with mating on your farm, contact your local rural professional.

Score regularly

BCS is not something that can be changed overnight. Therefore it’s crucial to score regularly so those not at target are quickly identified and action plans can be put in place before it’s too late! MINDA® allows you to record and keep track of body condition scores as well as see where they are in relation to the BCS target for the time of year.

Score accurately

Use a trained eye to ensure your scores are accurate. It won’t do anyone any good being generous with scoring when it comes to performance! There are plenty of materials available to get you up to speed with how to score. Alternatively you can use an accredited professional or do it with a neighbour to make sure it is fair scoring.

Use BCS to determine dry off

Together with expected calving dates, BCS should be used to determine when to dry off. Those further from target should dry off further from their calving date to ensure they reach calving body condition targets.

It’s important to note that there are approximately 40 days during a dry period that a cow does not gain BCS. A dry cow will not gain BCS for one to two weeks after drying off due to the active immune response involved in the drying off process, and will also gain very little body condition during the month before calving due to the large energy demand of the growing calf.

Run two mobs to ensure varying requirements are met

Different body conditions require different management. After you’ve scored the cows, draft out a lighter mob so you can cater specifically to their needs and ensure cows are getting the treatment they need to reach target. 

Preferentially feed animals below target

A key way to put condition on cows is to make sure you are giving them enough of the right type of feed. But remember, energy is only partitioned to BCS when maintenance, activity, pregnancy and milk production demands are already met.

Reduce milking of animals below target

Once a day milking allows the girls more energy to go toward maintaining or gaining body condition. Losses in milk production on a per day basis can be made back through extra days in milk in autumn.

With aged pregnancy results coming in, this edition of six tips will help you identify areas that might be holding back your repro performance.

Narrowing in on these factors will allow you to focus your attention where it’s needed the most – giving you the best chance to improve performance.

All of these can be done via MINDA® and will require good records. However, If you do not keep good records in MINDA®, these tips can be an opportunity for you to see what valuable insights can be gained from doing so.

Compare the in-calf rates (or not in-calf rates) between:

Late calvers and those that calved in the first six weeks of calving

If late calvers (those that calved after week 6 of calving) make up a considerable portion of the herd (aim for less than 13%) and are demonstrating lower performance, it’s likely the late calving group is holding back reproductive performance.

Look into your records to help understand why they’re getting in calf/calving late. You could also try some short term methods such as culling or the use of SGL to get back on track.

Animals that aren’t at target body condition score and animals that are

If those that aren’t at target make up a sizeable portion of the herd and have poorer performance, this will be a contributing factor to lowered reproductive performance.

To improve BCS, strategies such as preferential management, increased feeding, once a day milking or drying off early are all good options.

2 & 3 year olds should be 5.5 at calving, 4.5 at mating.
4+ year olds should be 5 at calving, 4 at mating.

Animals affected by health issues and animals that aren’t

If those affected are not performing as well as those that are then it’s likely cow health is a contributing factor to lowered reproductive performance. Take a look at what portion of the herd is affected by health problems to determine the urgency of the issue.

Talk to your vet to discuss precautionary measures and have a quick response to significant health issues that arise.

Different age groups within your herd

If there is a particular age group that is underperforming and represents a decent portion of the herd, look further into their records such as weights, BCS and health to determine why and take the necessary steps.

Different periods in time

Look at the in calf rates and see if there was a point in time where in calf rates dropped off. Consider timely events that could have caused this to happen. This could be anything from changing from AB to bulls to a change in weather or feed supply.

And finally, put it into action

Prioritise what area demands the most attention by looking at what portion of the herd falls into each problem category.

First set a goal (have fewer cows under BCS target), then create a plan and assign tasks to staff (preferential management for the suboptimal group with increased feeding, drying off early or once a day milking), and be sure to measure and track results (regularly scoring cows).

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Get the most accurate BCS results for your cows

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Get the most accurate BCS results for your cows

Get in touch to request a quote or find out more about Protrack BCS.

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