By Nick Collins & Alison Dewes
When mating rolls around each spring, the focus naturally shifts to heat detection, AB, conception rates and getting cows in calf.
But the foundations of a successful mating have been laid months earlier.
For Dr Alison Dewes, Farm Systems Support – Emissions Analysis, and Nick Collins, Farm Engagement Lead with Rere ki uta rere ki tai - Living Soil Project, reproductive performance is not something that can be separated from the wider farm system.
Cow condition, nutrition, mineral status, metabolic health, lameness, calving recovery, young stock management, genetics and even the daily pressure placed on animals all contribute to what happens at mating.
As Nick puts it:
“Mating in spring starts with drying off in autumn.”
It is a simple statement, but one that shifts the conversation from trying to solve reproductive problems at mating to creating the conditions for success well before it begins.
Start with the cow you want to bring into spring
Drying off provides an important opportunity to assess body condition and determine which cows need time and support to restore condition before winter and calving.
Nick recommends working towards body condition score targets of 5 for mature cows and 5.5 for first calvers, ideally reaching these targets around six weeks before calving.
From there, the focus becomes maintaining the cow through transition and early lactation so she arrives at mating in the best possible position.
Alison describes the goal simply: healthy, cycling cows on a rising plane of nutrition, with as few barriers to conception as possible.
That means mating should not be viewed as the time to suddenly correct condition. Feed quality, intake and body condition need to be considered well beforehand.
Younger cows deserve particular attention. Nick recommends aiming for first and second calvers to be at BCS 4.5 or above going into mating, while Alison suggests using tools such as Once-a-Day (OAD) milking for younger, lighter or late-calving cows where reducing workload could help protect condition.
“If you are precise, you will make progress.” – Dr Alison Dewes
Nutrition is about more than having enough grass
Good nutrition is fundamental, but both Alison and Nick encourage farmers to look deeper than feed availability alone.
Nick recommends using information already available on farm to build a clearer picture of what the animal needs.
Before drying off, liver biopsies from cull cows can be cross-referenced with autumn herbage testing to help identify potential mineral supplementation requirements through winter and into calving and mating.
Strategic blood testing can add another layer of information.
Alison recommends testing early enough that, if a nutritional or metabolic issue is identified, there is still time to investigate it and make an appropriate change before mating begins.
Nick also encourages farmers to consider milk urea nitrogen (MUN) levels. Excess protein leading into mating can create an additional energy demand on the cow, making it important to consider the balance of the overall diet rather than focusing on one nutrient in isolation.
Where appropriate, additional fibre such as free-choice hay can help balance pasture intake.
The aim is not simply to feed more. It is to understand what the cow is receiving and what she requires.
As Nick explains, during this period farmers are nourishing the cow and calf, setting the cow up for milk production and reproduction, and setting the calf up for life.
Find the cows that need help early
Not every cow arrives at mating from the same starting point.
Cows that have experienced retained foetal membranes, assisted calvings, twins, milk fever, ketosis, mastitis, lameness or other challenges around calving warrant closer attention.
Rather than waiting to see whether those challenges translate into reproductive problems, Alison and Nick both advocate identifying at-risk animals early.
Metricheck testing can be considered for cows with calving issues or where there is concern about uterine health.
Pre-mating tail paint and heat observations can also help identify cows that are not cycling before AB begins.
For non-cyclers, Nick suggests intervening early where necessary, while first ensuring the fundamentals of nutrition, condition, health and management are in place before investing in interventions such as CIDRs.
“Mating is one of the times of year when attention to detail really matters.” – Dr Alison Dewes
Reduce the pressures that quietly add up
Sometimes improving reproductive performance is not about adding another product or intervention. It is about removing unnecessary pressure.
Lameness is one example.
A lame cow is dealing with pain, reduced mobility and potentially reduced feed intake at a time when the farm is asking her to cycle, produce milk and conceive.
Nick encourages farmers to deal with lameness immediately, use hoof blocks where appropriate to improve comfort and mobility, and minimise walking distances for affected cows.
Alison similarly recommends looking across the farm for avoidable sources of stress, including excessive walking, long periods in the yard, poor tracks, heat, handling, competition for feed and inadequate access to water.
OAD milking can also be a useful management tool for cows under pressure, including lighter cows, lame cows and non-cyclers.
The question becomes: what can we change in the system to make it easier for this cow to perform?
Know what is happening before AB starts
Heat detection remains one of the fundamentals.
Alison recommends observing and recording heats before mating so non-cyclers and problem cows can be identified early, rather than discovering them several weeks into AB.
Once mating begins, heat detection needs to remain a priority.
Nick stresses the importance of having consistent systems in place, while Alison describes accurate heat detection as one of the details that can have a significant influence on reproductive performance.
The facilities matter too.
AB facilities should work well for the cow and the technician, with good systems that minimise unnecessary stress and allow the job to be done accurately and efficiently.
Breed deliberately for the herd you want
Mating is not only about getting cows in calf. It is an opportunity to shape the future herd.
Alison recommends deciding before mating which cows should receive the highest genetic-merit dairy semen and deliberately breeding replacements from the cows farmers most want represented in their future herd.
Once replacement requirements are covered, suitable beef genetics can be used across the remainder of the herd, considering calf value alongside factors such as calving ease, gestation length and suitability for individual cows.
Nick also encourages farmers to consider whether short-gestation genetics could help tighten the following season’s calving spread.
“The goal is to keep the cows you want to keep and breed replacements from the cows you most want in your future herd.” – Dr Alison Dewes
Replacement heifers also need to be part of the mating conversation.
Nick recommends a minimum target of 60% of mature liveweight at 15 months or first mating, with 300 kg liveweight or higher a useful target depending on mature cow size.
Their health and growth rates are not separate from herd reproductive performance. They are part of building the next generation of the herd.
Don’t forget the bulls
Where bulls are used for follow-up, preparation matters just as much.
Farmers need enough sound, fertile bulls for the number of cows expected to return, along with contingency animals should a bull become lame or unavailable.
Alison describes bulls as “athletes during mating”. They require good nutrition, sound feet and legs, appropriate health and fertility checks, and the opportunity to rotate and rest where possible.
Nick similarly stresses getting bull ratios right and prioritising their welfare throughout mating.
Do the basics well
There are plenty of tools available to support reproductive performance, from targeted supplementation and OAD milking to CIDRs, alternative animal health approaches, pre and probiotics, herbs, seaweed and cider vinegar tonics.
But Nick’s overarching advice is much simpler:
“Do the basics well.” – Nick Collins
That means starting with the fundamentals: healthy cows, appropriate body condition, good nutrition, sound feet, clean water, effective heat detection, good facilities, strong records and early intervention when something is not right.
Alison’s message is similarly focused on precision.
Every avoidable empty cow, late-calving cow or good young cow lost from the herd contributes to involuntary wastage and can slow the rate at which a herd progresses.
Getting the small things right consistently can add up to more cows in calf earlier, fewer avoidable losses, a tighter calving pattern and greater opportunity to retain and breed from the animals farmers value most.
A whole-system approach to mating
This way of thinking closely reflects the kaupapa behind Rere ki uta rere ki tai - Living Soil Project.
The project brings together farmer knowledge, Mātauranga Māori and science to understand farming as an interconnected system, with soil at the centre of relationships extending through pasture, animals, people, farm businesses and te taiao.
Rather than looking at individual outcomes in isolation, the project works with farmers to understand how changes within one part of the system can flow through to others.
Animal health and reproductive performance are part of that picture. The project includes animal health benchmarking and tracking alongside soil testing, farm system analysis, financial performance and farmer observations, helping build a broader picture of how farms respond as management practices evolve.
For mating, the same principle applies.
What happens during a few weeks of AB reflects decisions made across seasons: how cows were dried off, how condition was managed, what they were fed, how they transitioned through calving, how quickly health issues were identified, how much pressure was placed on them and how deliberately the mating programme was planned.
Successful mating is not one event. It is the result of a connected system working well.
Alison’s pre-mating checklist
☐ Have cows on a rising plane of nutrition
Aim for good-quality feed, increasing intake where required, and stable or improving body condition leading into mating.
☐ Protect vulnerable cows
Identify younger cows, lighter cows, late calvers and cows that have struggled through transition or early lactation. Consider OAD milking where reducing workload may help protect condition and support cycling.
☐ Reduce unnecessary stress
Look at walking distances, yard time, handling, tracks, heat, competition for feed and access to clean water.
☐ Identify cows that have had a difficult start
Pay particular attention to cows affected by retained membranes, assisted calvings, twins, milk fever, ketosis, mastitis, lameness or other health challenges.
☐ Check uterine health where there is concern
Consider Metricheck testing cows with relevant risk factors so problems can be identified and appropriately managed before mating.
☐ Consider strategic blood testing
Check for nutritional or metabolic factors early enough that there is time to investigate and respond before mating.
☐ Know which cows are cycling
Observe and record heats before mating. Use this information to identify non-cyclers and problem cows before AB begins.
☐ Have a deliberate semen strategy
Identify the cows you most want replacements from and use your highest genetic-merit dairy semen deliberately.
☐ Use beef genetics strategically
Once replacement requirements are covered, select suitable beef sires for the remaining cows, considering calf value, calving ease, gestation length and suitability.
☐ Get heat detection right
Make heat detection a priority throughout AB, with consistent systems and clear responsibilities.
☐ Plan your bull power
Have enough sound, fertile bulls available, including contingency bulls. Check health, feet, legs and fertility before use and consider rotating teams to provide rest.
☐ Have a plan for problems
Know how you will respond to non-cyclers, lame cows, thin cows, late calvers and cows with reproductive issues. Establish trigger points for intervention and involve your veterinarian early.
“Get the small things right consistently and they add up: more cows in calf early, fewer avoidable losses, a tighter calving pattern and faster genetic and productive progress. Mating matters.” – Dr Alison Dewes
