Many will argue that the breeding season is the most critical time of the year. Success or failure here will have serious implications on milk production for years to come.

Traditionally, successful breeding seasons were characterised as those that resulted in less than 10% of the herd empty at the end of the season. Increasingly, farmers and advisers are looking beyond this empty rate figure and are looking more and more at the six-week in-calf rate as a true measure of breeding success.

The six-week in-calf rate is different from the six-week calving rate as it looks at what happened during the breeding season whereas the six-week calving rate can be influenced by selling late-calving cows or introducing a lot of heifers into the herd that calve early.

Six-week in-calf rate is the percentage of the herd in-calf after six weeks of breeding and can be calculated after the breeding season is over through scanning or by calculating non-return rates.

The target six-week in-calf rate is 80%. This is being achieved by some of the best herds in the country but the national average picture is poor, well below 80%.

A high six-week in-calf rate is important as it ensures compact calving and compact calving increases milk production. As an example, take a herd with an 80% six-week in-calf rate and take a herd with a 50% six-week in-calf rate.

The compact-calving herd will have on average 30% more cows calved in the first six weeks. If we take an average of 21 days more production (half of the six weeks) at 1.8 kg milk solids (MS) per cow, that is 38kg MS per cow for the 30% of the cows that calved earlier or 11.4kg more MS for every cow in the herd.

In money terms, at a milk price of €5/kg that’s an extra €57 in milk sales per cow for every cow just by calving more compactly not to mention reduced breeding costs and lower replacement rate etc.

10 steps to a successful breeding season

Step 1: Use high-EBI bulls.

This is the best long-term plan for achieving good fertility results. Remember, if using genomic bulls you need to use at least five. Also, if thinking about using Jersey, remember to add about €120 to the calf’s EBI to take into account the hybrid vigour.

Step 2: Condition score

Target body condition score (BCS) for breeding is between 2.9 and 3.25. Cows within this range have the best chance of going in calf early in the season. Like Step 1, this is a long-term strategy and the best time to manage BCS for breeding was probably last autumn at drying off. What can be done to manage BCS now? The only real option is to put very thin cows on once-a-day milking.

Step 3: Feeding management

The best farmers will try and ensure the cows are on a rising plane of nutrition for three weeks before the start of breeding and for two weeks into breeding. This means that for this five-week period, no cow is fed less than the day before. This doesn’t just mean quantity, it also infers quality, which is why it is so important to have quality grass in the second and third rotations and why the top farmers focus so much on achieving good grazing residuals.

Step 4: Minerals

Minerals are like a link in a chain, when the pressure comes on, the weakest link breaks first. If your grass is deficient in certain minerals then it will stand to reason that your herd will be also. Some farmers will get their grass tested or blood sample a representative sample of their herd before deciding on what mineral to use, if any.

Step 5: Heat detection

Unless cows are submitted for AI, they won’t go in calf. It is amazing that so many farms with obvious fertility problems still don’t use heat detection aids correctly. Where tail paint is used it must be topped up regularly, at least twice a week. Remember, some cows in heat only get mounted once, and only for a few seconds. How much paint is removed after one mounting? Know the other signs of heat: soliciting, restlessness, tail swishing etc.

Step 6: Medical intervention

There is a spectrum of medical interventions available for dairy cows ranging from simple washouts to advanced synchrony programmes. Healthy and well-fed cows should not require much intervention to get back in calf. Intervention is required for non-cycling and irregular cycling cows and any cow that had a hard calving or a retained cleaning should get a washout. If the aim is to maximise the six-week in-calf rate, these cows should be identified and treated as soon as possible.

Step 7: Good records

Good records are essential to monitor progress and assist in identifying problem cows. A breeding chart on the wall of the dairy is probably still the most effective. A chart with the cows and their first and second choice AI bull is also useful. Many farmers will carry around a small notebook or a diary with them and write in any cow bulling and also any cows hanging around with the bulling cows and will keep a close eye on them over the coming days. Remember to periodically transfer the information to Herdplus if doing DIY AI. Monitor progress weekly – for a 90% submission rate, 30% of the herd should be submitted each week for the first three weeks of mating.

Step 8: Good facilities

Whether doing DIY AI or getting a technician, the person doing the AI has enough to be doing to do the job correctly than worry about the cow getting away or a gate falling. Safe, clean and efficient handling facilities are key to avoid stress on both the cow and man. Likewise, good drafting facilities make the job of picking out cows for AI far easier.

Step 9: Training

Before the start of the season, everyone working on the farm doing AI should go on a refresher course. Where farm staff are present, especially where new staff have been employed, the farm owner or manager should run through the signs of heat and discuss the protocol for the breeding season so everybody is mentally fresh and fully understands what is happening. Don’t presume that just because someone has an agricultural qualification or has worked on a farm previously knows what the signs of heat are or the biology surrounding mating.

Step 10: Bull power

Don’t be afraid to AI a cow if you are not 100% sure that she is in heat. It only takes one or two cows to go in calf after such a serve to pay for the straws used on a cow that was not in heat. Similarly, if a cow has a long heat, don’t be afraid to AI her twice. In the great scheme of things, the cost of a straw is a low price to pay for improving the six-week in-calf rate. After the period of AI is over, make sure there are enough bulls to cover the herd. The recommendation is one bull per 30 cows not in calf and to rotate bulls so as to reduce the risk of an infertile bull not getting cows pregnant.