Spring calving is drawing to a close on suckler farms around the country.
However, in many herds, there will be a small number of cows that can drag calving out for another month or more.
Later-calving cows are often a nuisance for farmers. When turned outside, they tie up fields that could be better utilised by stores or cows suckling calves.
If they remain housed, they require feeding every day and possibly require bedding as well. As farmers are preoccupied with fieldwork, these cows do not get checked as frequently and it is easier to miss a late-calving cow in the midst of a difficult labour.
Shortening the calving period can eliminate a lot of the problems caused by late-calving cows.
The goal for every suckler farmer should be to have spring calving finished up before the bull goes out to start breeding again.
But many farmers are put off the idea of tightening the calving block for reasons such as a shortage of calving pens, or the intense workload with so many cows calving in a short time period.
Shortening of the calving period should be done gradually. Aim to take one week to 10 days off the calving block every year.
This avoids having too many empty cows at the end of the breeding period. With breeding due to start in the coming weeks, outlined are 10 steps to shorten the calving period for next spring.
Cow fertility is influenced by sudden changes in diet and environment. Therefore, it is important that cows are settled at grass at least two weeks before the bull goes out.
Turning cows out to grass just as breeding starts, or midway through a breeding cycle, has a negative effect on animals coming into heat and conception rate.
This is often a problem for February-calving herds, as a late turnout can coincide with the start of breeding.
Keep cows on good-quality grass during the breeding season. Cows should be grazing short, leafy swards as much as possible.
Once grass heads out, either remove as silage or top swards. Grazing stem and seed heads will supply less energy in the diet and this can have a negative impact on cow fertility. Also, make sure cows are properly supplemented for minerals during the breeding period.
Breeding groups should be a mix of cows that calved early or in the middle of the calving period. This gives a better spread of cows coming back into heat, making it easier for the bull to cover the group.
Some cows naturally slip back in calving date after a hard calving, or when rearing twins. These cows should get priority management and feeding post-calving.
It may be worthwhile giving these animals a pre-breeding scan to see if there are any internal problems that will affect cycling activity or conception rates.
Capping cow numbers in breeding groups will ease the pressure on stock bulls. For a mature bull, 30 cows is more than enough if the aim is to shorten the calving spread. For young bulls in their first or second breeding season, as a rule of thumb, work to the basis of one cow for every month the stock bull is in terms of age.
For example, an 18-month-old bull in his first season should get a maximum of 18 cows to serve.
If the aim is to pull late-calving cows forward, keep this group smaller in size, again making it easier for the bull to cover animals.
The easiest way to bring calving to an end is to remove the stock bull on a set date and scan cows around 40 days later. Empty cows can then be sold.
Removing the bull 10 to 14 days earlier than last year avoids having too many cows scanning empty in the first year.
Some breeds, as well as some stock bulls, tend to have gestation periods around 300 days, rather than the usual 285 to 290 days.
Keep this in mind when picking a start and end date for breeding. For longer-gestation bulls, turn out and remove the herd sire 10 to 14 days earlier than for shorter-gestation bulls. This will keep cows calving closer together.
If taking the bull away from cows in August/September is not practical, then you need to be ruthless at scanning time. Cows that are calving late should be sold shortly after scanning.
If you do not take a tough approach to selling these animals, then don’t be surprised when spring calving runs into June again next year.
If you think there will be a higher than normal culling rate, put extra heifers to the bull to maintain breeding numbers. Alternatively, after selling late-calving cows, replace with in-calf heifers calving at a more suitable time next spring.
As calving comes to an end and there is the usual cohort of stragglers still to calve, list the tag numbers of these cows now.
Check back through the herdbook to see when they calved during the last three years.
If a cow is calving late as a once-off for a genuine reason, give the animal the benefit of the doubt.
But if the cows have been calving late for the last couple of years, these repeat offenders should not go to the bull this year.
There is currently a good market for springing cows.
Selling now or with a calf at foot removes the temptation to run late-calving cows for another year.
In herds that have multiple stock bulls, chances are there will be an easy-calving bull with a shorter gestation for serving breeding heifers.
If possible, pull out the handful of later-calving cows and run them with the shorter-gestation bull to bring them forward in calving date.
For some farmers, synchronising cows and using fixed-time AI may be a feasible option for shortening the calving period.
Repeat breeders can be swept up with the stock bull.
This option can be beneficial for farmers who work off-farm and use annual leave around calving time.
With fixed-time AI, just because multiple cows are inseminated on the same day does not mean they all calve on the same day.
Farmers who use fixed-time AI indicate there can be a calving spread of 10 to 12 days even when cows are served to the same sire.