How milk recording revival is identifying most efficient cows

Thirty years ago, milk recording was dropped from spring-calving herds intent on cutting out superfluous cost.

Breeding replacements became a simple strategy that focused only on the most fertile cows at the front of the block to create a 12-week calving spread.

But as herds have successfully repeated their compact calving pattern, there has been a turnaround.

See also: Why efficiency is the route to dairy farm sustainability

LIC farm consultant Piers Badnell reckons 50-75% of the spring-calving herds he works with are now back milk recording.

In part, this has been driven by milk buyers requiring tests for Johne’s control and cell count data for selective use of antibiotics at drying off.

The move has also been helped by the launch of more flexible services to suit grazing herds.

In addition, milk recording has now become a source of useful data.

Analysis finds the best performing animals in the herd to breed the next generation of heifers, and the focus has shifted somewhat to include both fertility and productivity.

Grass-based systems

Piers explains that productivity matters in a grass-based system because the limiting factor is how much grass can be grown.

This determines stocking rates and restricts herd size, unless grass yield can be improved, or more expensive purchased feed is brought onto the farm.

“If land area is the limiting factor, you need to find the most productive and efficient cows in your herd to breed from, because it is not profitable to buy in lots of feed,” he says.

However, cows also need to be weighed to calculate production efficiency, he points out.

Efficiency is expressed in kilograms of milk solids (MS) as a percentage of mature cow weight and worked out on an individual cow basis.

“This is about how much feed a cow converts into MS yield. The most efficient animal is 1:1 MS production to mature cow bodyweight.

“For instance, a mature cow giving 313kg MS, calving on day one of the block, will have brilliant fertility, but will not be a particularly efficient cow for her size.”

Piers adds that milk records can flag up how looks can be deceptive.

“A herd that looks uniform can have a range of cows with varying body depth and frame strength. One farm we worked with had an average mature liveweight of 543kg, but the range was 417kg to 736kg.

“So be aware that an ‘average’ always has a range,” he explains (see case study).

Sexed semen

As with any biological measure, whether it is height, weight or yield, he points out the results will always form a bell-shaped curve, so a range of values will be natural for every dairy herd.

“Over time, through breeding, it is possible to move the whole bell curve to the right by dropping the bottom cows out.”

Sexed semen is helping this process, with only the most efficient cows, in the first three weeks of calving (to ensure that heifers are as close in age as possible) bred to dairy sexed semen.

Equally fertile (yet lower yielding) cows can be served with beef sires.

“It means you don’t have to serve so many animals, so you can be more selective and you may breed to dairy for three and a half weeks,” explains Piers.

“Herds culling because of TB or Johne’s control will slow production and genetic progress, which makes it even more important to serve the right cows as there is a smaller pool to select from.”

Case study

Sarah Baker, Maristow Estate, Devon

Maristow estate cows © Sarah Baker

Analysing milk records

Analysing milk records has helped herd manager Sarah Baker to select the most efficient and fertile cows to breed better replacements.

As a result, she has seen improvements in herd efficiency, while making a more uniform herd by narrowing the spread in cow performance and size.

Mature weight now averages 516kg. Sarah says her aim is to keep cow size at roughly 500kg, breeding for a more consistent animal.

“Our milk solids production averages 470kg, or 91.5% of mature cow liveweight, so it has gone up, but the range isn’t as big as it was,” she says.

She explains that the herd’s genetics originated from a Holstein base in 2014, plus heifers from six different herds in Ireland.

When the 300-cow spring-calving herd on the Maristow Estate, Devon, converted to a lower cost grazing-based system, milk recording continued.

“We always liked the data, and it informs your decisions,” says Sarah.

She now records in-house nine months a year (with an extra person in the parlour) for greater accuracy.

This includes three Johne’s tests a year, plus cell counts, which are used in breeding decisions, culling selection, and selective dry cow therapy.

Cow efficiency calculation

With all records now computerised, Sarah says it is easier to rank cows and analyse numbers.

She keeps a monthly track of figures, then uses them in February to select cows and match them to appropriate sires.

Weighing is still a pen-and-paper exercise, however, and cows walk through a mobile race to a crush with load cells.

“We weigh every other year our mature, third-plus calvers in mid-lactation, then we cross-reference the milk recording data for combined fat and protein for each animal, so we know how efficient they are,” Sarah explains. 

She adds ] there are always some cows lighter or heavier than expected. “It makes you look at outliers and how big cows can be really inefficient – they eat more and yet production is not equal to their bodyweight.”

Criteria for herd replacements

Heifer replacements are bred from the top 43% of the herd based on milk solids production.

Sarah still looks for cows to be in the front end of the block to ensure they calve in the first six weeks.

“Now that we have sexed semen, it’s more like the top 35% of cows that breed replacements, and conventional beef semen is used on the rest of the herd.

“I select about 10% of maiden heifers to be bred to sexed semen as well, and the rest run with pedigree Angus bulls.”

Milk recording (and the detailed information it provides) has made Sarah more focused on the herd’s breeding and efficiency direction, she says.

“In terms of cost-benefit, we can’t put a figure on it. But there is greatly increased accuracy of the data, so you have very high confidence on your breeding decisions and which animals are culled as poor performers.

“Our heifers each year are now a much more consistent group in terms of size, growth and performance when they reach the herd.”