A successful breeding season is a key driver of profitability in a seasonal calving dairy herd. Good preparation and informed breeding decisions can significantly improve reproductive outcomes. The following article outlines practical steps herdowners can take to maximise herd fertility and long-term performance.
The goals of the breeding season are: 

• To maximise the number of cows in calf by the end of the breeding season. One of the biggest drivers of milk production within a herd is cow survival and herd maturity.
• To breed enough high EBI replacement heifers that are suitable for your farming system. These replacements should be born early in spring to allow them ample time to reach their target weights.
• To increase the value of beef calves produced by using high genetic merit dairy beef bulls that are easy calving with an acceptable gestation length.

 

Here are some tips to allow you to achieve these targets:

Pre-Breeding Preparation:

• BCS: The aim is for cows to have a BCS of 2.75 or greater at breeding. If there are cows that are not hitting this target, either provide additional feeding or milk them once a day. By milking these cows once a day and feeding them twice, you will reduce their energy demand while increasing their energy consumption, thus allowing them to gain body condition faster. Keep an eye on your bulk tank in early lactation, as any drop in yield or protein % can indicate an issue with negative energy balance.
• Pre-breeding heat detection: Heat detection should begin 3 to 4 weeks before the start of the breeding season. Record any cows seen in heat. Once you have heat detected for a full cycle of 24 days, identify any non-bullers. These are cows that are calved >35 days but were not seen in heat. These cows should be checked before the breeding season as they may require some treatment to bring them bulling.
• Herd Health: Aim to keep your cows as healthy and stress-free as possible during the breeding season. Ensure your herd vaccination programme is up to date and treat any lame cows now.

 

Problem Cows:
Problem cows should be identified early and assessed before the breeding season. Problem cows are any cows that have had a setback either 

• at calving e.g. difficult calving, twin births, retained afterbirths
• since calving e.g. milk fever, ketosis, LDA, mastitis, lameness etc.  

Late calvers and cows that are calved greater 35 days and not seen in heat should also be included in this group.
These problem cows should be vet checked and treated as necessary prior to the breeding season. This gives them the best chance of going back in calf and being retained in the herd.

 

Breeding Plans:
Cow Selection:
93% of herds in the top 20% for EBI, milk production and fertility are milk recording versus 64% of herds with an average EBI – this is not a coincidence.
When choosing which animals to breed replacements from, milk recording results are a critical tool for making informed decisions.
The Milk Recording Lifetime Summary Report ranks cows within your herd based on profitability and performance. This ranking allows herdowners to make effective breeding decisions. 
Cows in the bottom 20% of the herd are highlighted in red. These are your least profitable animals and should be bred to beef. 
Cows in the top 20% of your herd are highlighted in green. These cows should, where possible, be prioritised for breeding replacement heifers. Additional replacements can be bred from the highest-ranking cows within the middle 60% of the herd.

 

Sexed Semen:
Sexed semen is a more fragile product than conventional semen, so we need to be even more selective when choosing candidates for sexed semen straws. The following are some tips:

• Choose animals that are performing well in the herd and have a high genetic merit.
• Heifers and younger cows (< 5th lactation) have the highest conception rates to sexed semen.
• Cows should be calved > 50 days and not have had any setback – record keeping is essential here. Any cow that had twins, difficult calvings or any sickness after calving should not receive sexed semen.
• Animals should be cycling regularly.
• Cows should be in good body condition and heifers should have reached their target weights.
• Ensure animals are on a good plane of nutrition and that the diet is consistent in the lead up to breeding.

Accurate timing is critical for sexed semen – guideline is 12 to 20 hours after the start of standing heat. 

• Sexed semen will not survive as long in the cow as conventional – avoid inseminating cows that are too fresh. Signs of heat need to be gone off the cow.
• Sexed semen will work later in the heat than conventional – sexed semen has already gone through the process of capacitation during the sexing process, which means the sperm cells are ready to fertilize. This process takes 8 to 10 hours and takes place in the cow for conventional semen. 

 

Bull Selection:
When choosing bulls to breed replacement heifers, look at the cow EBI report especially the subindex figures, and focus on areas that need improvement before selecting bulls. Use a team of bulls - no bull should be used on more than 20% of the cows. This is to mitigate the risk of:
1.    The genetic value of the bull falling and ending up with too many replacement heifers from this bull.
2.    Fertility – despite rigorous controls and lab testing, the field fertility of bulls can drop from time to time.
Using beef AI at start of the breeding season will allow you to generate dairy replacements from your best females and allow you to produce high quality beef calves, improving the overall value of your calf crop.

 

Bluetongue:
Bluetongue is a viral disease that affects ruminants, including cattle and sheep. It is spread by biting midges. Transmission occurs when a midge feeds on the blood of an infected animal and subsequently bites an uninfected animal.
Temperature is a major factor in the transmission of Bluetongue. Temperatures of greater than 12-15 ℃ are required for the virus to replicate in the midges so the real risk period for transmission of Bluetongue is late Spring to Autumn.
Clinical signs of Bluetongue in cattle can include high temperature, reduced appetite, drop in milk yield, sores on the nose and inside the mouth, swelling of the face, lips and tongue, drooling, discharge from nose and eyes and lameness.
However, when looking ahead to the 2026 breeding season the greatest threat posed by Bluetongue is its effect on fertility. Bluetongue infection can result in early embryo deaths, abortions and the birth of full-term calves with severe brain deformities. We cannot predict how Bluetongue will spread amongst the national herd, but what we do know for certain is that vaccination is the only effective method of control.
Munster Bovine recently held a webinar on Bluetongue. For more information regarding Bluetongue, including Bluetongue vaccination, scan the QR code below which will bring you to this webinar.