A study conducted at the Agri-Food and Biosciences Institute (AFBI) and recently published in the Journal of Dairy Science, has highlighted that moderate input/moderate output winter calving systems are likely to deliver the highest margins on NI farms.

The findings of the study are in line with previous work done by AFBI economists (Anderson et al.) published in 2010, which sought to identify “robust” systems of milk production in NI.

The latest study is based on work done over three lactations starting in 2008, and involved 80 cows split across four treatments.

Two of the treatments used winter-calving Holstein cows, with one group housed full-time, and the other going to grass in the spring.

The other two groups were spring-calving, with one utilising Holstein cows and a second group of Holstein Jersey cross.

Cows in the winter-calving groups were fed more concentrate, had higher milk yields, and those kept inside full-time, were in better body condition score than cows in any other systems.

However, these fully housed cows had a higher incidence of mastitis, lameness, and tended to have a longer interval from calving to conception than the spring-calving cows.

Stocking rates

The study also calculated whole system stocking rates, and while the rates were highest for the group housed full-time (2.99 cows/ha), the differences were perhaps less than expected, with the spring-calving groups around 2.50 cows/ha.

The AFBI scientists point out that while purchased concentrate can, in part, replace land, the higher meal feeding was also associated with increased forage intakes.

As a result, land is still required, but relevant to the NI context, this land does not have to be located close to the parlour when cows are housed full time.

While stocking rates were relatively similar, total milk output per ha was very different, with the full-time housed group producing 25,706kg of milk/ha, compared to the spring-calving crossbred cows at 14,564kg/ha.

Economics

In terms of economics, the spring-calving systems produced the highest gross margins per kg of milk, while cows housed full-time had the highest margins per ha.

However, the AFBI scientists argue that margin per cow is perhaps the most useful metric for NI farmers, given that cows must be housed over the winter, and it is the cost of this accommodation that is the true limiting factor to expansion, not land.

Despite the large variation in output across the systems, when the data was analysed on a gross margin per cow basis, the differences were actually “relatively modest” concludes the AFBI research.

Net margin

The data was further analysed on a net margin per cow basis across different milk and concentrate prices.

The group of cows that were winter calving, but turned out to grass in the spring, delivered the highest net margins per cow at medium and high milk prices.

At low milk prices, and especially if concentrate price was high, spring-calving systems performed best.

Fully housed systems generally produced the lowest net margins across all the scenarios assessed, as they are susceptible to low milk prices, high concentrate costs and associated with high fixed costs.

The environmental impact of the different systems is to be examined separately.

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