Do you know which cows in your herd have their condition against them for mating?

Do you know which cows in your herd have their condition against them for mating?
Do you know which cows in your herd have their condition against them for mating?
By Katrina Roberts, Herd Health Veterinarian, Anexa Vets

Grass growth rates during June and July have been very good across the Waikato and most farms managed to get to target average pasture cover for calving. However, there wasn’t much of a feed wedge on many farms, with a large chunk of the farm with the same cover. Combined with the wet weather, these longer covers have led to higher than desirable grazing residuals on some farms. What does that mean for future rounds? Well of course it depends on what the weather throws at us now but it may mean that next round or the round after pasture quality is reduced. The knock -on effect of this maybe that some cows lose more condition before mating.

The period between calving and mating is the most stressful period for a cow and responsible for the largest condition loss throughout the season. Very inconvenient when we’re already under time pressure to get a cow in calf again.

After a dry period break where a cow just has to eat, the approach of calving precedes a rapid increase in energy demand and metabolic changes for the cow:
  • Calving process
  • Milk production
  • Walking long distances
  • Competition with herd mates
We are expecting her to also put some energy aside for mating – this means growing follicles ready for conception with all hormonal changes that accompany this.
Initially following calving the cow cannot eat enough to meet her daily energy demands, leading to BCS loss. Typically we see a BCS loss of about 1 between calving and mating. In order to be in good shape for mating cows need to have not lost too much BCS and be past the low point i.e. gaining BCS coming into the mating period.

So the groups of cows we need to focus on with respect to mating are (as without action they will have reduced performance;
  • Cows under BCS 4.0 coming into mating
  • Cows that lose more than 1 BCS between calving and mating
  • Cows that calved in BCS less than 5
  • R2s and R3s that calved in less than 5.5
  • Late calving cows (that are still losing BCS at PSM) as they haven’t reached peak DM intakes at PSM

So how are you going to measure this?

Individually scoring the herd a few weeks before PSM gives you the opportunity to identify these individual animals that are at risk of poorer reproductive performance. If there are enough of these at-risk animals then you can consider a management strategy to get them back on track. We can do this during milking, or with metrichecking. But please be sure to book it in as it will require another person to do the recording/scoring.

What can we do with these cows once we’ve identified they need a hand?

  • What proportion of the herd is it? Does the management change need to be for all cows or just those identified (a small subset)
  • Splitting these cows into their own mob so they are preferentially fed
  • Reducing milking frequency for a short-period such as OAD milking or 3 in 2 (combined
  • Checking the diet and intakes for these cows (the subset as well as the whole herd) to ensure you are feeding to meet their daily demand with high energy feed in a way all cows can have equal access (do we have an issue where pasture quality maybe limiting the performance in this subset of cows or PKE trailers meaning that some cows are well fed others are struggling)
  • Check we don’t have a subclinical ketosis issue – this maybe a state of negative energy balance. We can test a group of animals cow-side to see if this is contributing to the issue.
For help with any of this or more information or to book in your whole herd individual BCS contact your vet.

Date Added: Wednesday, 19th August 2020