A target for most spring calving herds across the country is to achieve a submission rate over the first three weeks of 90% while limiting the number of missed heats in the herd.
For a herd with 100 cows, this means that 90 cows will be served in the first three weeks of the breeding season.
Maximising the three-week submission rate is important, as while not all of the cows are going to hold to their first service, it means that you have given them a chance and yourself a chance to get them in calf the next time around within the first six weeks.
Achieving a 90% three-week submission rate and a 90% six-week calving rate is important within a pasture-based production system, as the tighter and quicker cows calve down, the more days in milk leading to more solids produced.
There are a number of factors underpinning high levels of reproductive performance beyond just effective heat detection, and includes optimal body condition score, disease control, pre-breeding checks and intervention, and the genetics of the herd.
The consequences of a missed heat is a slip in the calving date of affected cows in the following and subsequent years, and increases the likelihood of a cow being empty at the end of the breeding season.
Cost of a missed heat
A Teagasc study conducted in 2021 estimated that a missed heat costs €149.50 in a 12-week breeding season, due to a combination of slippage in calving date costing €52.90 and €96.60 for the increased likelihood of a cow being empty.
The study showed that dairy cows are more active than usual for a period of around 17 hours during heat, but 55% showed standing heat for less than eight hours.
This study highlights the importance of effective heat detection through tail painting, scratch cards, or heat detection monitors and collars.
It also emphasises the importance of carrying out pre-breeding checks on the farm, tail painting the cows that are bulling another colour and identifying the cows that are not bulling.
These non-bullers should be checked by your vet and potentially flushed out if needs be and put onto a synchronisation programme to increase their chances of going in-calf within the first six weeks of breeding.
The study also identified that due to the random nature of standing heat, cows need to be heat detected three times a day, or for many, this is automatically done through collars and heat detecting tags.
Submission rate
To achieve the 90% three-week submission rate, farmers need to be submitting 4.3% of their herd each day at the beginning of the breeding season which equates to five cows a day for a 100-cow herd.
Waiting until breeding has already start to detect cows that are not cycling means that you will be at least three weeks into breeding before treatment can occur.
This highlights the importance of carrying out pre-breeding checks right up until the start of breeding so an effective plan can be put in place for the non-bullers in the herd.
With the heavy rain experienced across the country in recent days, it is still important to maintain the cow’s dry matter intake through grazing grass to sufficiently meet the herd’s energy requirements.
Focus on ensuring that the energy requirements of cows are being met and if extra feed needs to be sourced do that early and in harsher weather in the last few days, a small bit of extra silage or meal might be no harm.
A mid-day feed of soya hulls or beet pulp could increase the energy and dry matter intake of cows, and are also simple to add into and take out of the diet.
But for the most part, grazing conditions are still favourable and that rain may just increase growth rates, so it is important to stay ahead of grass and ensure cows are achieving optimal residuals.
