Ways to shift to autumn calving to avoid milk penalties

Demand from dairy processors for a consistent milk supply is encouraging farmers to review their production profiles. Even some of the most committed spring calvers are introducing changes to create a more even supply to capture the financial potential of their milk contracts.

See also: Advice on getting extra help for autumn block-calving

This has been evident in the past five years but is gathering momentum as spring milk price deductions start to outweigh the financial advantages of low-cost production.

Autumn switch

Some farmers have acquired a second unit to establish an autumn herd. They have secured an agreement from their milk buyer to treat that farm and the principal holding as one to enable the business to achieve a level supply profile.

Others with a single herd are transitioning cows to autumn, especially farmers who have the infrastructure to facilitate that, says LIC consultant Sean Chubb.

“The milk contract is always the biggest driver, but there are also farmers who have a dry farm and struggle to get good forage over the summer. They can make plenty of silage for the winter but can’t meet grazing needs in the summer,” he says.

“If they have the costs already built into their systems, these farmers might see the financial and practical benefits of drying off cows to calve in the autumn,” he says. “They won’t need to make big changes to their cost structure but will be removing the stress over the summer grass situation.”

Transitioning cows from spring to autumn calving can be done in different ways using strategies that prevent over-conditioned cows and metabolic disorders.

© Tim Scrivener

Transitioning a split block

Sean advises transitioning cows over one year but recommends that farmers first produce a budget to assess the impact of doing so on cashflow, and to get a third party to review it.

If the budget is tight, and the plan is to move a lot of cows from one calving block to another in a single year, the implications of that on milk volumes will have consequences for cashflow, he says.

If moving the entire group at once puts too much pressure on cashflow, he recommends aiming for a two-year transition.

This involves calving half the group in the autumn of the first year and the rest in the second.

Making the transition in one year has advantages for the breeding of heifer replacements, says Sean.

“All the replacements can be bred from one group so farmers won’t need to juggle two herds that are calving, mating and drying off at the same time.”

Milk run-over cows or dry off

Preserving milk supply will maintain cashflow, so drying cows off as close as possible to 60 days from their due calving date is advisable. Some cows will naturally dry themselves off though and will need to be managed for an extended dry period.

Sean says deciding whether to maintain lactation should be balanced with factors such as possible spikes in somatic cell counts (SCCs) from milking stale cows.

Cost is also a factor: “If the milk supply isn’t there, farmers should weigh up whether or not it is worth putting concentrates into those cows and consider the cost of turning on the milking equipment to run through animals that might be giving very few litres of milk.”

Prevent over-conditioning

It can be tricky to maintain body condition score (BCS) within the recommended range. If cows are dry for a protracted length of time, they are in danger of gaining too much condition, which could result in calving difficulties or metabolic disorders.

Even cows with a shorter dry period have the potential to become too fat, Sean warns.

“Unless the groups can be segregated for feeding, the cows that will be maintained as spring calvers and those transitioning to autumn will be fed as one group up to the spring.

“This means the autumn calvers will be receiving feed at a higher rate than they need.”

Cow type also has a bearing on condition. “Yields in cows with North American genetics will probably drop down to 20 litres when transitioning.

“Even if they are milked for 500 days, it is their yield that will lift if you give them additional feed, not their condition. But the more typical block-calving breed will most likely preserve it as condition,” he explains.

Feeding strategy in the dry period

Cows will need good-quality feed in the three weeks before calving, but lower-quality silage can be offered before that transition period if it’s providing cows with their required protein needs.

Sean advises aiming for 14% protein across all feed types in late lactation and 12% when cows are dry.

“As long as the feed has the necessary protein and cows are not losing condition in the run-up to them drying off, lower-quality feed is fine because they won’t be producing much milk. It’s just a case of setting them up for the following year.”

© Debbie James

When to serve a cow transitioning from one block to another

If herd fertility has historically been good, Sean recommends serving run-over cows in the farm’s planned block.

But if there have been issues with fertility or there are concerns about mating on concrete for the first time, he suggests bringing mating forward by two weeks.

“Giving those cows that extra fortnight will be beneficial in terms of getting them in-calf the following year,” he says.

Because the milk supply of transitioning cows will be lower than it would otherwise be at that time of the year, providing them with an energy surplus will generally increase fertility, he adds.

When cows are empty for a long period, it can impact on their fertility because egg (oocyte) quality will be lower.

“Generally speaking, these factors should balance each other out and, unless there are issues with feed quality, farmers should aim to try to hit the industry recommended breeding standards,” says Sean.

Whether to calve heifers at 30 months into an autumn block

Although serving heifers to calve at 30 months instead of the target 24 months increases rearing costs, Sean suggests these costs will be earned back in the first lactation, as they will produce greater volumes of milk.

As long as the heifer is genetically ready for serving to calve at 24 months, there will be no reduction in her longevity in the herd if mating is delayed to allow her to calve later, at 30 months, he says.

“If everything is as it should be in terms of BCS, and you delay serving that heifer by six months, she will be better able to compete with the older cows than she would otherwise have in her first year. Her performance will be better as a consequence.”