There are many different factors which farmers would consider when describing what defines a good suckler cow. Ultimately, however, the best cows in any herd are those who consistently produce a calf every 365 days and have the ability to rear that calf efficiently until weaning.

This week, we review scanning results and weaning weights across the group.

Routine weighing on the farms has shown a small increase in 200-day weights over the three years, moving from 267.09kg in 2017 to 268.51kg in 2018 and 272.85kg in 2019. Scanning results increased from a rate of 91.22% in 2018 to 93.01% in 2019.

Fertility

The single best figure to measure true fertility within a herd is a scanning percentage from a defined breeding window.

The farms within the programme scan cows once breeding has finished (usually early to mid-September), and at a point in time to pick up pregnancies across a breeding period of approximately 12 weeks.

It means that some of the cows scanned as empty may actually be a couple of weeks in-calf (assuming the bull has remained with the cows), but as they have fallen out of the desired breeding window, they are counted as barren.

Figures

Table 1 outlines individual figures across the group.

Overall, the group averaged 93.01% in-calf across 873 cows and heifers bred over 12 weeks. This is an improvement, but still below the quoted target of 95%.

Experience would suggest 95% is not easily achieved at a group level. It could be improved by leaving the bull in for longer than 12 weeks, but that would be counterproductive.

Looking more closely at the figures, Paul Jamison has seen a dramatic rise from 78.75% to 92.41%.

However, the 2018 figure was not a true reflection of cow fertility, but more so of an infertile bull. With late calving cows culled, it has resulted in an improved figure for 2019.

Barry Carty’s figure has fallen to 84%. Barry’s spring-calving herd is really a winter-calving herd, with calving starting in December. He will try to AI the majority of the cows before going to grass.

From 26 cows, 22 were scanned in-calf after AI. The four which had not been artificially inseminated failed to conceive while running with the bull at grass.

On Barry’s farm, cows are fed high-quality (70+ D-value) silage along with 1.5kg of meal during the breeding period.

Going from this level of nutrition to wet marginal grazing land can produce a negative energy balance, so it is difficult to get these cows settled in-calf soon after turnout.

In the future, Barry plans to really tighten up calving dates within this winter herd and use only AI up until cattle are turned out to grass. There is currently no stock bull on farm.

Identifying the most efficient suckler cow in your herd

To help identify the most efficient cows in the herd, farmers on the programme routinely weigh both the cow and the calf at weaning time.

The target is to produce a calf that weighs 50% of cow weight at 200 days.

Shown in Table 2 are the results from all spring-calving cows on the 10 programme farms.

On average, calves were 43.05% of mature cow weight at weaning, a decrease from 44.06% in 2018.

However, good grass growing conditions in 2019 saw calf daily liveweight gains improve from 1.14kg to 1.17kg, but average cow weight across the farms also increased to 640kg in 2019, compared to 624kg last year.

Factors

While weighing cattle at weaning, and working out a weaning % is a useful management tool, there are many factors that can influence the final result. These include:

  • The level and timing at which creep was introduced to calves. An increased level of creep feeding would increase actual calf weaning weights and therefore corrected 200 day weights.
  • When the calf is weighed. Weights used to calculate the corrected 200-day weight should be as close to the 200-day mark as possible.
  • The percentage of younger breeding animals within a herd. This is especially the case with herds that calve heifers at two years old, as at weaning this first calved animal is still unlikely to be at her mature weight.
  • The body condition score of cows. Cows in good condition at weaning will naturally be heavier, and potentially require less feeding during the dry period, thereby reducing costs.
  • Setting those flaws aside, a balance must also be sought, and the weaning % from one year to another at individual farm level will identify poor-performing cows within a herd.

    Averages

    Averages within a herd can then be improved by selecting replacements from the best performing cows and culling those consistently in the bottom percentages.

    For example, on Alastair McNeilly’s farm, the top 5% of cows with male calves (based on weaning %) produced calves that were 59% of cow weight at 200 days, while the bottom 5% are only 31% of cow weight at 200 days.

    Often it’s quoted that regardless of weaning percentage, a bigger cow produces a bigger calf. The analysis of actual data may suggest otherwise.

    On Alastair’s farm, these top 5% of cows are on average 131kg lighter than those in the bottom 5%. The calves from the top 5% of cows were 133kg heavier at 200 days.

    That is a difference of 1.6kg of daily liveweight gain versus 0.93kg. This trend is similar across all the farms.

    Autumn

    An average calf growth of 1.17kg per day for both males and females is excellent.

    However, those farmers measuring calf weights regularly throughout the grazing period saw a notable fall-off in growth rates from September onwards, due to the unsettled weather at the time.

    Read more

    Fertile suckler cows at Glenwherry

    Watch: Bullocks drafted for slaughter one month earlier