How to economically achieve a 365-day calving interval for suckler cows – Teagasc

Analysis carried out in 2014 found that the annual cost of keeping a suckler cow on Irish beef farms ranged from €550 to €700.

This was for farms with high levels of management and where the length of the grazing season was approximately 220 days.

The range in suckler cow costs on these farms was primarily a reflection of differences in feed, replacement heifer and breeding costs.

Where levels of management are lower and/or the length of the grazing season is shorter than this, then it is likely that suckler cow costs are greater.

Although farmers can adopt management strategies to reduce suckler cow costs (e.g. calving close to the onset of the grazing season so that feed costs are minimised), these costs are likely to remain the predominant cost for suckler beef farms.

Thus, the objective for suckler systems is to minimise costs while producing a healthy and heavy weanling annually so that suckler cow costs per calf or kilogram of weight weaned is minimised.

The quality (muscularity) is also important, particularly for farms selling weanlings. One of the key measures determining the cost and annual output of suckler beef cows is the calving interval.

Calving interval describes the number of days between successive calvings. The target calving interval for a suckler cow is 365 days; where the calving interval is greater than 365 days this means that it takes longer than one year for a cow to produce successive calves.

The overall effect of longer calving intervals is to reduce profitability for suckler beef farms for the following reasons:

  • For spring calving cows, which represent the vast majority of our suckler herd, the length of the indoor winter feeding period is longer since cows are normally not turned out to grass until after calving. This is a critical issue for our seasonal calving production systems where the objective must be to maximise grazing season lengths and thus, the proportion of grazed grass in the annual feed budget. Thus, longer calving intervals increase total feed costs.
  • Where weaning occurs on a fixed date, weaning weights of the later-born calves are lower. For example, if a cow calves on March 1 and the calf is weaned on October 1, then the age at weaning is 7 months. If this cow then calves on April 1 the following year (representing a calving interval of 396 days) and the weaning date remains October 1 then the calf is only 6 months of age at weaning and correspondingly, 30kg to 40kg lighter.
  • The likelihood of a cow with a longer calving interval becoming pregnant and remaining in the herd is reduced. This is because later calving cows have a shorter duration prior to breeding or indeed may be calving when the breeding season has already commenced. The overall effect of this is lower pregnancy rates and higher cow replacement costs, a considerable cost in suckler beef systems.

There are also health risks (mixing of calves of different ages and levels of disease exposure), marketing difficulties (selling uneven batches of calves) and management/labour challenges (for example, repetition of husbandry tasks such as disbudding and castration as calves reach suitable ages on different dates).

It is also important to consider that costs are typically expressed on an annual basis but if calving intervals are greater than 365 days then the cost of maintaining suckler cows per calf weaned is greater than the annual cost.

Take the example of a cow with an annual cost of €600 and has a calving interval of 396 days (one year and one month) – in effect the cost of this cow per calf produced is €650.

In short, higher calving intervals reduce output and increase costs per calf or per kilogram of weight weaned.

The overall cost of longer calving intervals, taking into account the above factors, has been quantified as €2.20 per day change in calving interval. Data from Irish Cattle Breeding Federation (ICBF) indicates that the average calving interval for suckler cows in Ireland is 403 days.

Using this cost estimate and the national average calving interval and applying it to a herd of 50 cows, total farm costs are increased by almost €4,200 (50 cows x 38 days longer calving interval x €2.20/day), a considerable cost particularly in the context of suckler beef systems where margins are low.

Indeed across the national suckler cow herd of approximately one million cows, this represents a cost of almost €85m to the industry.

Overall it is clear that the length of calving intervals on suckler beef farms is an important factor influencing profitability.

The three most important factors controlling reproductive performance are level of management, herd health and genetics.

Attention to all of these factors is required for high levels of reproductive performance, short calving intervals and profitable suckler beef systems.

Paul Crosson, Research Officer, Teagasc, Grange

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