Farm Ireland

Wednesday 24 January 2018

Mating season gets into full swing for calving herds

The potential for next year's calving profit is being determined now.
The potential for next year's calving profit is being determined now.

Mary Kinston

For spring calving herds, the mating season is now in full swing. This means the potential for next year's profit is being determined now. Current conception rates will dictate next year's six week in-calf rate and the resultant days in milk that will be achieved.

Achieving a compact calving spread offers the possibility of higher milk sales and improved profitability. However, a significant and understated benefit is the management simplicity compact calving offers.

For example, a protracted calving spread results in a farmer managing more groups of cattle in the form of dry cows, calving cows, freshly calved milking cows, big and small maiden heifers, newborn calves and weaned calves. All at the same time you are trying to focus on mating cows.

In contrast, a compactly calved herd makes it easier to rear uniform replacement heifers fit for breeding and offers the opportunity to end calving (and possibly even weaning of replacement heifer calves) before mating begins.

Some even take the small window of opportunity it offers prior to mating to take a break away. So it's definitely worth the effort.

With this in mind, good operators are diligent and actively manage the herd for a compact calving spread. To do this needs measurement, targets and triggers. Remember that targets are areas to strive for (an ideal) whereas triggers are prompts to investigate a problem and act on it.

For the milking herd, the first target that should be given due consideration is the submission rate at 21 days. To calculate this relies on accurate records of AI or bull inseminations.

As highlighted by John Donworth in recent weeks, the submission rate is calculated from the number of cows inseminated in the first 21 days divided by the number of cows that have calved by day 21 of mating, multiplied by 100.

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Note also that it is the number of cows – not the number of inseminations – as some cows may have had two services in this 21-day period.

Top farmers target and often achieve a three-week submission rate of about 90pc. If you have not yet reached 21 days, remember this can also be considered on a weekly (30pc every seven days) or daily basis (more than 4pc per day). However, if the submission rate is less than 80pc, you need to assess why more than 20pc of the herd is not submitting for service and act on it. Management areas to consider are the non-cycling cow's situation.

Key element

Assess how many days she is post calving, her condition score, lactation number, problems at or after calving, etc.

While you can't alter the fact that a cow may have recently calved, you can help cows and heifers which have poor condition by milking them once a day and by treating cows which had problems and are now dirty.

Another question to consider is whether your heat detection methods are adequate?

Obviously a key element to a good submission rate is good heat detection. If you have new or young staff helping you this year, remember to talk about the signs to look out for and don't just assume these are already known.

Key points to make are that a cow is most likely to be on heat if:

* She is standing to be mounted by other cows;

* Tail paint is removed or heat mount detector is triggered.

However, a cow may also be on heat if:

* She attempts to mount other cows;

* Tail paint is rubbed but not removed, or heat mount detector is lost;

* She is restless or bellowing;

* She has poor milk let-down;

* You see mucus around the vulva;

* You see mud marks on the flanks, or rubbing on pins and tail head.

Heat detection is easiest in the first three weeks of breeding. As it gets quieter, many farmers opt to introduce a teaser/vasectomised bull to aid activity and detection. Regularly topping up tail paint and strategic use of different coloured tailed paint for whether she's served or not can all aid in your mating management.

Finally, as we draw closer to the introduction of bulls to the herd and the end of the AI period, make sure that you have adequate bull numbers in the paddock, with a spare one or two to cover lame and overworked bulls.

The table shows the required bull numbers for varying herd size, submission rate and AI period assuming a conception rate of 50pc. Always round numbers up to the next whole number, so that a requirement for 1.4 bulls equals two in practice. Also a 'half resting, half working' bull rotation policy will require double the number of bulls shown in the table.

  • Mary Kinston is a discussion group facilitator and consultant, and farms with her husband in Co Kerry

Indo Farming