Breeding dairy cows with greater fertility and longevity not only increases lifetime milk yield, but reduces methane emissions and carbon footprint per litre of milk produced on NI farms.

Speaking at last week’s EU sustainable dairy farm webinar, Ballywalter-based dairy farmer James Brown outlined the efficiency changes implemented to make his farm more sustainable.

James runs 160 cows, plus 100 followers, on a 195-acre grassland unit. Cows are predominantly Ayrshire breeding, with about 15% of animals Norwegian Red.

Around 1m litres (6,250l/cow) is produced annually at 3.4% protein and 4.3% butterfat with 1.2t of concentrate fed per cow unit.

The herd is mainly spring calving, with 80% of cows calving from 10 January to 31 March, with the remaining 20% calving from 15 October to 10 December.

Breeding robust cows

Breeding has focused on fertility and milk solids. “I want cows that last longer and produce milk which returns a higher price per litre.

This increases longevity of the herd, meaning we get greater lifetime production and more profit per cow.

There are more than 25 cows in the herd that have produced over 50t of milk, with the highest yielding cow producing 79t in her lifetime,” said James.

Replacement rate

Breeding for fertility, combined with use of sexed semen, has seen replacement rate dropping as low as 16% in recent years, although in 2020, it is currently running at 21%.

The NI average replacement rate is more typically 35%, meaning for every 100 cows James runs 14 fewer replacements. With CAFRE benchmarking showing heifer rearing costs of £1,800, it is a significant saving.

A lower replacement rate also means fewer animals on farm and less emissions produced. All heifers are calved down at 24 months of age to get them into production as early as possible, further reducing the carbon footprint per litre.

Genomics

This winter, the plan is start genomic testing heifer calves to identify future herd replacements at an earlier stage.

Genomic testing will also allow for harder culling. James is planning to remove the bottom 10% of the herd annually and replace animals with younger cows capable of giving greater output from similar feed inputs, which will again contribute to lower emissions per litre.

Milk from forage

At present, cows yield over 3,000l from grass, or 9,000l of milk from forage for every 1ha farmed. Grass yields in 2020 amounted to 13t DM/ha grown, with 11t DM/ha utilized. Cows go to grass as early as ground conditions permit in February.

Fertiliser use

Slurry is applied using a trailing shoe on grazing and silage ground. Soils are topped up using chemical nitrogen and potash (K). No phosphate-based fertiliser is applied.

Energy saving

Also speaking on the webinar, CAFRE dairy adviser Conail Keown outlined how technology and genetics can be used to make farms more sustainable.

He said there is a huge variation between farms for standard tasks such as cooling milk. Based on information submitted through Business Development Groups, these costs can vary from £2 to £6 for every 1,000l of milk produced.

Processing

The webinar also heard from Neville Graham, who outlined how Dale Farm is working with suppliers to utilise software packages that monitor farm inputs and milk sales.

To date, the data shows the investments giving the greatest efficiency returns are feed-to-yield systems and heat detection software.

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