Mastitis Multiplex PCR – A big advance in milk quality management

Many of you will be aware of the highly convenient, Staph aureus PCR test that LIC has had an available for use on herd test samples for the last 10 years.

This season the test has got better. As well as a much improved sensitivity (improved chance of detecting Staph aureus if the cow is infected with it), the test will also simultaneously detect Strep uberis, Strep dysgalactia and will look for the presence of the BLAZ gene.

Cows detected with Staph aureus can be managed separately over the season to minimise spread to other cows. At the end of the season, these cows may be considered for culling (particularly if they possess the BLAZ gene, have been chronically high SCC or are greater than 6-7 years old.

The finding of either Strep species at a high incidence provides some certainty of the main cause of high somatic cell count cows and gives a greater confidence in the retention of younger infected cows when treated with DCAT as cure rates should be high.

The BLAZ gene is found in bacteria that are resistant to beta lactam antibiotics - e.g. penicillin. Cow milk found to contain this gene have bacteria on board which are less likely to cure with antibiotics and pose a risk to the development of herd level antibiotic resistance. Cows with Staph aureus and the BLAZ gene should definitely not be retained.

Testing of herd test samples must be booked with LIC in advance via our vet clinic. Talk to your Prime Vet. Once the herd test results are through, your Prime Vet will screen the HSSC cows and select those for testing. Typically these will be cows that are chronically high or with a SCC over 250-400,000 at the most recent herd test.

Cost of testing is $19 per cow (excluding GST). This is very good value. A minimum of 25 cows must be sampled.

Precision Dairy – From Monitoring to Insights

The 4th International Precision Dairy Farming Conference was held in Christchurch this December, bringing together almost 400 researchers, farmers and tech developers from 22 countries. The clear message? We’re moving beyond simply monitoring cows toward systems that combine multiple data sources, use AI, and deliver practical advice. The concept of ‘digital twins’ – virtual farm models that simulate decisions before you make them – featured prominently. Here are some technologies making waves right now.

Automated Calf Feeders

Early calf nutrition has lifetime production consequences – but intensive milk feeding is labour-heavy. Automated feeders let you push growth rates without the workload, and the data they generate is proving just as valuable as the milk they deliver:

• Individual calf ID with customised milk allocation

• Automated step-down weaning programs

• Health insights from drinking speed, visit frequency and intake patterns

Calf Health Monitoring

What if you could treat sick calves before they looked sick? Wearable tags combined with feeder data are now detecting illness before clinical signs appear:

• Scours flagged 24 hours early through changes in drinking speed and intake

• Detecting early rumination to help with weaning decisions (when are the calves eating grass??)

• SenseHub calf tags for rumination and health monitoring are available in NZ now.

FLOW – The AI Backing Gate

Inconsistent backing gate use is a hidden cost on most farms – stressed cows, longer milkings, and more lameness. With changing staff and growing herds, the problem is getting worse. Christchurch company Livestock Visibility Solutions has built an AI system that standardises gate movement using cameras – in a trial use showed:

• 18.5% reduction in milking times across 9 farms

• 15-20% reduction in lameness

• $47,500 average annual savings (labour, lameness, power)

Camera-Based Monitoring

A single BCS tells you where a cow is – daily scoring tells you where she’s heading. Cameras that automatically score BCS have been around for a few years now, but are markedly improving (see the NZ company Herd-i as an example). Teamed with the ability to detect locomotion changes, we can now follow daily trends in BCS and lameness:

• Track BCS changes over time – not just snapshots, allowing early action on nutrition

• Act on individual cow trends (rather than just mob level data) – preferentially feed cows, matched to in-shed feeding technology

• Treat lame cows earlier - improving cure rates and reducing milk / repro losses

Satellite & Smartphone

Pasture Tools

We all know regular pasture measurement pays – but compliance with actually doing this is relatively low across the industry. Satellite technology’s are improving at pace (no longer plagued by inconsistent readings!), but can be improved markedly by the addition of on-ground readings i.e with manual reading adjustments or photos. AIMER and Halter (both NZ companies) have grass measurement + AI assisted feed wedge analysis tools on the market now to offer not just cover prediction, but also insights on feed planning.

What’s Next?

The common thread is integration. The future isn’t more gadgets – it’s smarter systems turning data into actionable advice.

Phantom Cow Scanning to Reduce Empty Rate

Phantom cows at scanning time are often the most frustrating. These are the cows that get inseminated don’t return to heat but fail to get pregnant. They often come as a surprise when you assume they will be in calf.

Traditionally we scanned phantom cows around week 7 of mating, soon after the bulls went out as knowing who was mated by the bulls required a lot of diligence and hard work. However, with the increase in cow wearables and farms doing all AB mating our chance to intervene can be at any point in the mating period.

Mating lengths have also gotten shorter meaning treated phantom cows only get one insemination before the end of the mating period.

With this in mind, 2 years ago Ryan Luckman and I did a study on maximising the returns on when to scan and treat phantom cows. We used data from 30 herds in Waimate who did all AB matings without any phantom scanning, in total about 25,000 cows. We then used this to estimate when the best time to phantom scan was. The conclusion was that if you want to maximise the return on investment then scanning right at the end of mating and mating treated cows on the last day maximised returns and makes the biggest change in herd empty rate. On average this would reduce herd empty rate by 1.1% and give a massive 4.2 return on investment.

For this to work well good AB records are vital and using the shortest gestation semen available in these cows is recommended. To find out more call your prime vet. If you did all AB mating last season and want to know the likely return on phantom scanning in your herd we can estimate that for you.

Why is Cow Performance Elevated when fed DDGS?

DDG (Dry Distiller Grains) or DDGS (Dry Distillers Grains and Solubles) has rapidly become a mainstay component in many in-shed feed blends. Cows love it and so do the farmers using it – the lift in milk response is very consistent. So why is this??

DDG is a by-product, produced from the production of ethanol out of primarily maize grains. On the face of it, it has a good ME (13MJME/kgDM), fat at 9% and a high crude protein percentage of 28%.

Undoubtedly there is an advantage in using a blend that is highly palatable and DDG certainly ticks this box. Shy or picky eaters in the shed disappear making consistent intakes of concentrates assured.

The real magic from DDG though is not in the fact that it is high in crude protein per se but in its ratio of Rumen Degradable Protein (RDP) to Rumen Undegradable Protein (RUP). The heat treatment involved in the production of DDG means that a high proportion of its crude protein (~60-70%) is in the RUP form. Compare this with spring perennial grass that is around 10-25% (and white clover lower again).

RDP is the protein that is used by rumen bugs for themselves to grow in the presence of carbohydrate. This creates microbial protein that the cows then digest further down the gut. RDP that is surplus to microbial requirements results in urea production in the rumen, with excesses disposed of in the urine (and increased MUN values).

High production cows need an increasing amount of RUP in the diet to support lactation. In TMR rations built for high producing cows the aim is to have a crude protein ratio of 65% RDP and 35% RUP. An RUP surplus is not as readily lost to the formation of urea, meaning that it has little influence on Milk Urea Nitrogen levels (MUN). RUP provides essential amino acids that may be low in microbial proteins which can be production limiting.

Heat treated Soy Meal, late stage (flowering) cut Lucerne and Red Clover are all high in RUP (particularly when conserved in a higher dry matter form – baleage or hay). Also keep in mind that with increasing production there is an increase in calcium requirements by the cow. DDG, Barley, Wheat and PKE are all very low in Ca.

Humeral Fractures over Mating

As we head into October, we often see a second surge of spontaneous humeral fractures in heifers (the first period being around one week on either side of calving).

It is interesting that in affected farms it is very rare to see fractures occurring in both the peri-calving period and the pre-mate/mating period.

This would lead us to think that that nutritional intakes of calcium and phosphorus (and their ratios) in the 1-3 months before the fracture occurs may have an association.

We know that heifers that fracture in the pre-mate/mating period are generally in the top 20th percentile for production in their co-hort. It therefore makes sense that these will have the highest calcium demand, which could lead to thinning of the bones if calcium intakes are not supported.

Recent studies have shown that low liver copper values found in heifers with fractures may not be the cause of fractures but rather due to the effect of thinning bones. The body scrambles to fortify thin bones with copper containing proteins and enzymes.

Many of our diets are low in calcium and/or have a low Ca/P ratio. PKE, fodder beet, cereal grains and maize are all low, and this year we have measured some surprisingly low Ca percentages in pasture (possibly created by low pH soils).

For high producing herds the supplementation of lime flour in heifers (as well as cows), should be an essential practice until they get beyond peak lactation in November.