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The breeding season is getting under way for the majority of suckler herds around the country, with cows served in the next week calving down in early March.
Outlined are a series of steps which can help to improve conceptions rates during the breeding season.
1 Prioritise cow groups, especially first-calved heifers and thin cows
Where a suckler herd has two or more stock bulls available, or uses AI to serve cows, batching all first-calved heifers together as a separate breeding group is a good way to improve conception rates.
Heifers will be under more physical and nutritional stress to cope with the demands of early lactation compared with mature cows.
If heifers are struggling to maintain milk and body condition over the coming weeks, running these animals as a separate group allows supplementary concentrates to be fed for a short period.
The same advice applies for cows which are extremely thin during the breeding period, or those which are rearing twins as some concentrate feeding may be required.
As the number of these animals tends to be small, they can be combined with the heifers to minimise the number of breeding groups and make best use of stock bulls.
In smaller herds where only one stock bull is available, it is not practical to purchase a second bull for a handful of heifers or thin cows with twins.
Using AI would allow these higher-priority animals to be managed separately. However, if this is not an option, then it is essential that thinner cows are managed on high-quality grass to increase conception rates.
2 Group size
Limiting the number of cows in each breeding group will take the pressure off the stock bull, especially where the aim is to maintain a tight calving pattern.
As a rule of thumb, a young bull in his first season should get one cow for every month of age, ie an 18-month-old stock bull should run with no more than 18 cows.
Mature bulls should run with no more than 30 to 35 cows where the aim is tightening the calving pattern to a 10- to 12-week period.
3 Mix early and late-calving cows
Where cows are batched in two or more breeding groups, it is a good idea to have a mix of early and late-calving cows in each group.
If all of the early calving cows are grouped together, there are likely to be several days when multiple cows are in heat at the same time. This will put any bull under pressure.
By mixing early and late-calving cows, there will be a more gradual spread of animals coming into heat, making it easier for the stock bull to cover animals and result in higher conception rates.
4 Keep cows on high-quality grazing swards
The breeding season usually coincides with the period when cows are in peak lactation. Therefore, breeding animals have an increased energy requirement. If cows are not getting sufficient energy in their diet, both milk and fertility will suffer.
Where cows are turned out to good-quality grass after calving, dry matter energy intakes are higher and as a result, cow fertility will be improved.
Grazing cows on swards which have headed out, with a high percentage of stem present, will do little to improve conception rates.
Therefore, setting up a simple grazing rotation, or using temporary electric fencing to control grass quality, will have a positive impact on cow fertility.
5 Mineral supplementation
Ensure cows are properly covered for trace minerals, either using a mineral bolus or lick buckets. If lick buckets are used, a rule of thumb is one bucket per 10 cows.
6 Record heats and service dates
If using AI as the main breeding method, recording heats and service dates is easier to carry out compared with natural service.
However, when using natural service, do not simply turn the stock bull out with cows and forget about him for the next three months.
It is still important to monitor cows for heat activity, as well as checking that the bull is mounting cows correctly.
Record service dates and check for signs of repeat breeding activity three weeks later. There will always be a few animals repeating.
But if you are noticing a high number of cows observed in heat and mated, then the bull may be infertile.
Picking this up early will give you time to replace the bull without any major slip in the calving pattern next year.
Monitor cows for a period of 20 to 30 minutes morning and night, and if time permits, during the afternoon.
7 Rotate stock bulls
As a safeguard against an infertile, or a sub-fertile bull, it can be good practice to rotate stock bulls between breeding groups midway through the breeding period.
This way, if there is a problem with the first bull’s libido or semen quality, the second bull should hopefully cover any empty cows in the second half of the breeding period.
8 Stock bull at the ready
Are stock bulls in the best possible condition to start the breeding season? For young bulls recently purchased at a breed society sale, it is best practice to gradually wean these animals off concentrates before turning out to cows.
In addition, stock bulls should be sound on their feet and mobile. If not, move quickly to correct this situation, but be careful when handling the animal.
A quick examination of the bull’s testicles will highlight any lumps, or possible problems, that could impede breeding performance.
Once the bull is turned out with cows, ensure the animal is mounting cows correctly and that the penis is not corkscrewed.
9 Dealing with late-calving cows
Every herd has a handful of problem cows that persistently calve late every year due to poor fertility. Consider what these cows deliver to the herd if they are held for another year.
Late-calving cows cause plenty of problems such as weaning lighter calves off grass at a higher cost as concentrates are required to maintain milk production and calf performance in autumn.
Selling off these animals as a cow and calf unit will remove the temptation to hold these animals for another year.
They can be replaced by holding another heifer, or buying an in-calf animal from a special breeding sale or herd dispersal, which is scanned to calve down next March or April at a more convenient time.
However, if there are productive cows calving late this spring, due to a sub-fertile stock bull last year, culling these animals is not always practical. Putting these animals straight in to high-quality grass will give them an energy boost and hopefully bring them back into heat quickly.
In addition, it may be worth using a sire breed that tends to have a shorter gestation period.
Using a shorter-gestation bull means that the later-calving cows should calve down earlier next spring, bringing them back in line with the main cow herd.
10 Pick an end date
Pick a date to remove the bull from cows. That way, there will be a definite end to spring calving next year. If cows are currently calving in a 15- to 16-week period, take the bull out two weeks earlier this year.
Repeat this step again next year to have cows calving in a compact 12-week block. This way, there is less risk of a high barren rate from taking the bull away too early in one year.
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