A compact calving pattern is essential to maximise profitability on a grass-based system. In order to increase chances of gaining compact season, high submission rates in the first three weeks of the breeding season are essential.
eagasc research has shown that each missed heat can cost as much as €206 in a spring calving production system.
Identify non-cycling cows
Research has shown that underweight cows pre-breeding are going to have lower submission rates and lower conception rates, leading to a poor six-week in-calf rate.
Teagasc has shown that one of the most effective ways to increase the body condition score of a cow is to revert to once-a-day milking in the three weeks leading up to the breeding season and to maintain it for at least three weeks after insemination.
By moving under-conditioned cows onto OAD milking, it will prevent further condition loss and should increase the BCS over a period of time. This in turn will improve the breeding performance, as the cows will be under reduced pressure to produce milk.
Also, the use of a pre-breeding heat detection such as tail painting or a pre-breeding ultrasound scan should be used to identify non-cycling cows.
These should be synchronised by injecting them with a shot of prostaglandin, providing they are calved over 30 days.
Those who fit into this category should all be synchronised on day 21 of the breeding cycle.
As a rule of thumb 30pc of the herd should be submitted for AI by the end of the first week of the season, 60pc by the second week and 90pc by the third week.
These figures should be recorded on herd management software system or in a diary and intervention should be taken. Often these will be cows who had a calving difficulty earlier in the spring, a metabolic disease or other health issues.
Following calving, the uterus of every cow becomes contaminated by bacteria. Most cows can clear these bacteria naturally without treatment. Around 10-20pc of animals will be unable to clear these bacteria in a timely manner, and will subsequently develop a form of endometritis which can have an adverse effect on reproductive performance — endometritis is linked to poor conception.
One of the best ways of examining this is by conducting a metri check prior to breeding. The process involves a veterinary visit where at-risk cows are examined using a device which scoops discharge from the anterior vagina. Depending on the appearance of this discharge, a cow is diagnosed as having endometritis or not.
If the cow has endometritis veterinary intervention is required.
Poor heat detection is one of the main reasons for poor submission rates on farms. Teagasc research has shown that 55pc of cows show signs of heat for eight hours or less a day, with later calving cows showing less again.
This means the time for observing heats is severely limited. Teagasc recommends that farmers should monitor cows for heats at least three times a day with the aid of heat detection.
Replacement heifers should be targeted early in the breeding season. This is important to ensure a compact breeding season, so when these heifers calve down next that they will calve in time and have enough time to go back into the herd.
There are a number of protocols that can be used to synchronise heifers.
One of the simplest and cheapest ways to ensure all heifers are inseminated is to use a prostaglandin protocol. However, this requires that all heifers must be cycling beforehand, and daily heat detection is also needed.
All heats should be observed as normal for the first week of breeding. All heifers should be submitted as they come into heat, with one third on average being submitted in the first seven days.
At the end of the first week remaining, two-thirds get a prostaglandin injection.
Most will show signs of heat and be submitted two to five days later. Remaining heifers who don’t respond get a second prostaglandin injection 11 days later.
All the heifers are then inseminated between 72 and 96 hours later regardless of whether they display signs of heat.
The main advantage of this system is that it will allow all heifers to be inseminated within 21 days of the breeding season, with the majority submitted within the first ten days.
Fixed time AI
Fixed time AI is suitable for heifers that are not yet cycling and also no heat detection is required.
A progesterone device is inserted into each heifer (PRID, CIDR etc.) and they also receive an injection of GNRH.
Three days prior to the date of insemination the device is removed and each heifer gets a daily injection of prostaglandin three and two days prior to AI.
And 48 hours after the second shot of prostaglandin, the heifers get the second GNRH injection and are also inseminated.
One of the most effective ways to increase the body condition score of a cow is to revert to once-a-day milking in the three weeks leading up to the breeding season, and to maintain it for at least three weeks after insemination
Feeding for fertility: it’s all about a balanced diet
Striking the correct balance in dairy cow nutrition is vital, especially when it comes to the breeding season.
Ensuring a cow gets enough dry matter and enough energy in her diet is the most important thing when it comes to breeding management
According to Teagasc a cow will reach her highest daily milk output 6-8 weeks after calving but will only reach her highest intake of dry matter 10-12 weeks after calving.
The cow will use energy from her fat reserves (‘off her back’) to take up the energy deficit for several weeks. However, if the cow loses too much body condition in early lactation, it can reduce her chances of getting back in calf again.
Cows calving onto a grass-based diet will eat a total dry matter intake (DMI) of 8-10kg DM (grass + concentrates) in week one after calving and should increase by 0.75-1.0kg DM every week until they reach peak intake at 16-18kg DM during week 10-12 of the lactation.
Insufficient energy in the milking cow’s diet can result in poor fertility, loss of body condition score as well as increased susceptibility to disease and metabolic disorders that may have a knock-on effect when it comes to fertility such as ketosis.
A cow’s energy requirements can be met through grazing high-quality swards and offering supplementary feed where necessary.
“Grass will make up the majority of a cows diet during the breeding season, so grazing clean, good-quality swards is important to getting enough energy into the cow’s diet,” says Joe Patton of Teagasc.
“The cow should aim to graze covers of 1400-1600 DM/ha minimal stem and no seed head. The average cow requires 15 to 16kg of good-quality grass at a dry matter of 18-20pc.
Covers should be grazed to around 4cm, which strikes a balance between clearing out the paddock and keeping the cows well fed.”
Grass measuring plays an important role in this because it enables a farmer to see any deficit in farm cover before it arises and allows them to introduce a buffer feed on time should the need arise.
A typical ration for breeding should typically be a mix of roughly one-third of a protein source (distillers, gluten etc), one-third of a fibre source (beet pulp, hulls etc) and one-third energy (maize, barley etc).
This should provide good high-energy ration with an adequate amount of protein of around 14pc which complements high-quality grass to ensure all of a cow’s basic dietary requirement are met.
Only after all of these needs have been met should a farmer turn his attention to ensuring a cow has enough minerals in the diet.
Phosphorus, calcium, copper, cobalt, iodine, selenium, zinc, vitamin E and manganese all play a role in optimising cow fertility.
If you are having persistent issues with fertility in your herd, blood-testing cows in consultation with the vet may be useful to identify any deficiencies.
Teagasc research shows the main trace mineral deficiencies that occur in Ireland are copper, selenium and iodine, with a lower prevalence of zinc, manganese and cobalt deficiencies.
Deficiencies of these minerals are associated with poor reproductive performance, and reduced milk production.
Maintaining consistency in a cow’s diet and a balanced rumen during the breeding season is vital to attaining a good in-calf rate.
This can be done through a consistent balanced diet throughout the breeding season.
A diet that contains too much protein can result in excessive body weight loss as the cow metabolises the extra protein, causing an energy cost to the animal in excreting the excess protein.
Fibre also plays an important in maintaining a healthy rumen.
Cows have a specific requirement for fibre. When this is not met, rumen pH becomes unstable and animal performance suffers.
Maintaining consistency in a cow’s diet during the breeding season is vital to attaining a good in-calf rate.
And not changing the diet is also important, says Celtic Sea Minerals nutritionist Seamus Callanan.
“Cows don’t like change in their diet, we’re asking an awful lot of them this time of the year between being at peak milk yield, peak intake and trying to get them back in calf,” he says.
“The least we can do is help her by keeping her diet as stable as possible, so farmers shouldn’t be changing feeds.
“High volumes of lush grass can cause changes to the rumen and cause difficulties to arise such as increased acidity in the stomach.
“This can be stopped by providing a fibre source like straw, by adding a rumen buffer or yeast which can help mitigate this”