Reproductive management

Our team has an excellent knowledge base to assist you with decisions relating to reproductive management.

Our “Seasonal Reproductive Management” seminar series start after each pregnancy testing season have had excellent feedback. We also offer the following services; pregnancy testing (both ultrasound and manual palpation), metri-checking, non-cycling cow treatments, oestrus synchronisation, and bull breeding soundness examinations.


Getting the best return for non-cycling treatments

Recent trial work has shown that the economic benefits of treating non-cycling cows are due to increased days in milk and increased numbers of AB calves. This means getting the best economic return for treating non-cycling cows comes down to getting cows in calf earlier in the season. Because of this it is important to identify which cows are not cycling as early as possible so that you can reap the maximum return for your effort.

Which treatment should you use?

There are two treatments available for non-cycling cows. The two protocols are outlined below:

  1. GPG - the GPG protocol is a course of three injections over 9 days. It is the cheaper of the two available treatments but the results are not as good as the CIDR program.

  2. CIDR program - this protocol uses the same three injections as the GPG program but we also use a CIDR insert. Using the CIDR insert improves the effectiveness of the program but it does also increase the cost.

Recent research by Scott MacDougall has shown that the CIDR program is the most cost-effective program to use. Despite the higher initial cost it gives twice the economic return of using the GPG program.

Take away messages:

  • Treating non-cycling cows early in the season does provide a significant economic return to your business.

  • Identify and start treating non-cyling cows before the planned start of mating to maximise the returns.

Both treatment programs will provide significant returns but the most cost-effective program is the CIDR program.


Early Pregnancy Testing

Pregnancy status in cows can be accurately established from 6 weeks onwards. For farmers wishing to get the maximum information regarding their herd’s calving dates, scanning in two stages is recommended. For most, the first scan is done 6 weeks from the last AB date, with the final scan 6 weeks after the bulls have finished.

Some of the benefits of early scanning include:

  • Accurate ageing allows you to make decisions about cows that should be bought back from grazing early and cows that can stay off the milking platform for longer. This can be extremely valuable in cold, wet seasons where lower grazing pressure in the spring can save covers and soils on your milking platform.
  • Early calving cows in light condition are identified early in the season. This ensures you have time and options to achieve body condition targets and information to improve your drying-off decisions.
  • Late-calving cows in good condition can be milked longer in the autumn, increasing milk yield without sacrificing body condition score.
  • Accurate ageing of pregnancies will greatly assist you in assigning cows to the springer mob next season.
  • Identifying late calving cows that might be suitable for inducing, should that option continue to be available. Inductions will not be permitted without accurate pregnancy test data. We have had a number of herds over the last couple of years where only the very late (November) calvers could be induced because there was no information available on the October calvers with the herds scanned in April.
  • Providing accurate information for sale animals
  • Checking the success of your CIDR program

Please refer to the article on MINDAmobile recording for the most recent information on computerised recording at pregnancy testing time.


MINDAmobile Pregnancy Test Recording

Computerised recording at pregnancy testing time was a popular option last year and we received great feedback from clients who used the service.

After the successful trial last year we have upgraded and have three MINDAmobile units available so we should be able to offer the service to all clients who want it.

How does the system work?

  • You assign Tararua Vets permission to access your MINDA so that we can download and upload data to your account. Please ring and talk to our front office staff about how to do this and what information we need to access your account.
  • The night before pregnancy testing your herd we will synchronise with your account and download your details onto our handheld computer.
  • As we pregnancy test we will call results to you and you enter these directly into our computer.
  • After pregnancy testing, we take the computer back to TVSL and upload the data to your MINDA account. There is no need for you to double handle pregnancy test records.
  • At the same time, we can access fertility focus reports and help identify any areas that you can improve on over the next season.

Some major benefits of computerised recording are:

  • No double handling of pregnancy test records. All results are uploaded to your computer system without you having to re-enter results at home.
  • All mating dates are immediately available to us as we pregnancy test, improving the accuracy of ageing pregnancies even further.
  • Any number double-ups are identified on the day and these can be compared to birth-ID’s, correcting the problem instantly.
  • There are less recording errors.
  • Pregnancy test results can be analysed efficiently and quickly to highlight any problem areas on your farm.

Call us today to confirm what you need to do so that you can make the most of computerised pregnancy testing.

NOTE: Computerised recording does not cost you any more than regular paper recording.


Disappointed with your herd's reproductive performance this season?

A few common issues that contribute to poor reproductive performance are:

Low body condition

Ensuring that your cows are in adequate body condition at calving and mating is one of the most important steps you can take to help the fertility of your herd. It has been shown over and over again by multiple studies that body condition at calving and at mating plays a huge role in the reproductive performance of NZ cows.

What are the targets?

  1. Cows – Body condition score (BCS) of 5 at calving time with a minimum BCS 4 at mating. This means that cows should not lose more than 1 condition score between calving and mating.

  2. First and second calvers – BCS of 5.5 at calving with a minimum BCS 4.5 at mating. They should not lose more than 1 condition score between calving and mating.

First and second calvers are often hit the hardest in spring and because of this they often are the worst performing age group at scanning time. These young cows need to be in excellent body condition and need to be fed well throughout the early lactation period if you expect them to do well at mating time. A big loss in body condition after calving will reverse all the hard work you put into getting your heifers in top condition.

What we tend to observe is that many farmers overestimate the body condition of their herd by half a body condition score. A useful exercise is to get someone from off the farm in to look at and score your cows. So get a neighbouring farmer round and then return the favour for them, and if you can’t agree ask your vet next time we are around. Dairy NZ provides excellent resources on body condition scoring cattle and these can all be accessed through


Wide calving spread

Herds that have a spread out calving pattern have lower 6-week in calf rates and often struggle with high empty rates. A major reason for this is that these herds have late calving cows that don’t have time to recover from calving and heal their uterus before the start of mating. It takes the average cow approx. 45 days (6-7 weeks) to cycle after she calves.

On seasonal NZ dairy farms, there is a 12-week gap between the start of calving and the start of mating. Therefore if a cow calves after week 6 of your calving period she is unlikely to be cycling by the planned start of mating. If a cow calves after week 11-12, then she will miss the entire AB period.

The InCalf target for the 6-week in-calf rate is 78% or more. Having a large proportion of cows pregnant early in the season means they calve early and have time to recover and start cycling before the planned start of mating.


Bull numbers

A theme we have noticed on many farms that have higher empty rates is that bull numbers are often below recommended levels. We recommend a bull power of 1 bull to every 35 non-pregnant cows. Bull power refers to the number of bulls in with the cows at any one time. We also recommend that you use two teams of bulls and rotate them between work and rest every 4 days.

Below is a worked example for a 300 cows herd with a 6 week AI period. On average 65% of cows will be pregnant after a 6 week AI period.

300 cows = 195 pregnant after 6 weeks AI (65%) =105 empty

105 empty cows/35 = 3 bulls (required bull power)

Therefore 2 teams of 3 bulls rotated every 4 days = 6 bulls total


Bull illness/lameness

Many farms in the area had problems with bulls going lame over the mating period. Any bull that goes lame or becomes ill during the mating period or in the 2 months before mating is likely to have impaired sperm production and because of this should not be considered suitable for mating. Any injury, infection or illness that causes a fever will affect a bull’s sperm quality for the next 60 days. Bulls can be difficult to source in the middle of the mating period so it is recommended that you have several backup bulls on your property.

Preventing lame bulls – a huge proportion of bull lameness is caused by walking, mounting and fighting on races and concrete. The best system for preventing lame bulls is to train bulls to stay in the paddock when the cows go to milking. The bulls are then shifted to the next paddock to wait for the cows. It may take a few days but the bulls soon adjust to the regime. If this is not practical then at least ensure that bulls are not on the concrete yard during milking. Before the gates on the round yard are closed, walk through and push all the bulls out.


BVD virus

BVD continues to be a problem in the district with BVD suspected to be the cause of several poor scanning results. BVD can cause two very different syndromes:

  1. Diarrhoea for two weeks, often accompanied by a drop in milk production or a growth check in young stock. Most animals recover without any treatment although some may develop secondary infections due to their immune system being stretched too far. If a bull catches this form of BVD when he arrives on your property his sperm production will be significantly impaired for the next 60 -90 days.
  2. If a cow is infected with BVD for the first time while she is pregnant BVD can cause:
    • Early embryo loss which presents as long returns and more empty cows at scanning
    • Abortion at any stage of pregnancy
    • Birth of weak, dummy or deformed calves
    • Birth of a BVD carrier animal, also known as a PI.

Active BVD infections in a herd are often due to a BVD carrier animal being present. This carrier animal can either be a young cow, heifer or calf, or it can be one of the bulls that you brought onto the farm for mating.

Preventing BVD on your property:

  • Ensure all bulls are tested for BVD virus before they arrive on your farm. Also, make sure that they have been fully vaccinated against BVD.
  • Fully vaccinate all heifers on your property before their first mating
  • We can test bulk milk samples from your vat to assess how much BVD is circulating on your farm and to see if there is a carrier animal in your milkers. Remember any lame or mastitis cows not being milked into the vat will not be represented in this test
  • If you are concerned about your farms BVD status get in contact with us and we can give you more information on how to combat BVD.

These are just a few of the major issues that we have noticed this season. Poor reproductive performance is often complex with many contributing factors. If you are not happy with your performance this year and want to change please contact the team at Tararua Veterinary Services. Both Ben Allott and Mary Lund are trained InCalf advisers and will be more than happy to assist you. 


Metri-checking and treating endometritis

Endometritis is chronic uterine inflammation that can affect up to 30% of cows after calving and is a major cause of reproductive failure in New Zealand dairy herds.

Risk factors for Endometritis include:

  • Retained foetal membranes
  • Assisted or difficult/prolonged calvings
  • Induced cows
  • Twins
  • Birth of dead calves
  • Metabolic problems such as milk fever, ketosis or grass staggers around calving

Cows with endometritis have significantly lower conception rates, lower submission rates and higher empty rates than un-infected herd mates. Multiple studies have shown metri-checking and treating to be an effective treatment well worth the effort and cost.

The Metri-check™ sampling cup is used to detect pus within the reproductive tract. These cows are then treated with a dose of intrauterine antibiotic. From approximately 4-6 weeks after calving the uterus has involuted and will no longer expel pus. This means that cows checked more than 4-6 weeks after calving may have severe inflammation present in the uterus but not receive appropriate treatment because they don’t have pus at metri-checking.

Trials have also shown that by testing only ‘at-risk’ cows, you may be leaving up to two thirds of dirty cows in your herd unchecked and untreated.

At TVSL we have developed a tail-painting system for the easy identification of cows to metri-check at each appointment through the season.

  • All cows that calve in the first four weeks are tail-painted blue. After four weeks change the tail paint colour to green.
  • At week 6 all blue cows are metri-checked. You can either draft blue cows out or run the whole herd in and only blues are checked. This ensures all checked cows have been calved for a minimum of two weeks and a maximum of 6 weeks.
  • After 8 weeks switch to yellow tail-paint.
  • At week 10 all green cows are metri-checked. Again all yellow cows will be between 2 and 6 weeks calved.
  • At week 14 all yellow cows are metri-checked.


Calving week1
















Metricheck blues.

Any dirty painted green











Metricheck greens

Any dirty painted yellow







week 13




Metricheck yellow



This tail-painting program ensures all cows in your herd are metri-checked at the appropriate time while making the identification of cows to check quick and easy.


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