Total confinement Vs pasture systems: What does the science say?
COMMENT: There is considerable interest in the use of total confinement and zero-grazing dairy systems. This interest has spiked in recent times on the back of this year’s late spring and fodder crisis, together with the term du jour of ‘sustainable intensification’, further highlighted in this year’s Agri-Food Strategy report Going for Growth.
However, maintaining growth in the Northern Ireland dairy sector is a major challenge, particularly with land availability a considerable limiting factor. In this environment, many dairy producers are questioning what the best production system for their situation is.
To help inform this debate, AgriSearch have funded a review, entitled ‘Total Confinement vs. Pasture Systems: What does the Science Say?’ This project, conducted jointly by researchers at the Institute for Global Food Security at Queen’s University Belfast and dairy scientists at AFBI Hillsborough, is reviewing global dairy science literature to examine the advantages and disadvantages of total confinement and pasture systems.
A holistic approach will be used to assess the production, health and welfare, economic and environmental implications of each production system. So far, 196 relevant studies have been identified and results are still being collated. However, some major themes have already emerged.
The central benefits of total confinement systems stem from the high level of cow management that can be achieved. Under such high input systems, cows typically exhibit higher levels of performance (increased milk and milk solids yield). These systems also enable dietary management to increase dry matter intake, combating negative energy balance and helping maintain body condition.
In addition, cows are not exposed to adverse weather conditions, nor is the land degraded by poaching. However, the production costs involved in total confinement systems are considerably higher than those involving pasture. Indeed, it is only with larger herds that the benefits of economies of scale can really be achieved. This raises the related issue regarding attitudes to herd size, with the idea of ‘mega-dairies’ proving controversial.
On the other hand, grass is the cheapest feed available and systems incorporating pasture are less costly and typically achieve higher profitability (per litre, per cow) when compared with similar herd sized total confinement systems.
Additional benefits of systems incorporating pasture include; increased health (decreased lameness and mastitis), increased cow welfare (decreased mortality/culling rates, increased comfort/lying behaviour and decreased aggression), improved reproductive performance and fertility, improved milk composition (for example milk FA profiles), and lower environmental impacts, including green house gas emissions. These are considerable benefits.
Preliminary results clearly indicate there are advantages and disadvantages of each system.
Could it be that with the conventional Northern Ireland system of winter housing and seasonal pasture, producers are already adopting a ‘best of both worlds approach’?
It is also worth noting that the majority of consumers (95 per cent in a recent UK study) do not think it is acceptable to keep cows permanently housed indoors. Surely this represents a marketing opportunity with its current clean green producer image.
The industry is at a cross roads in terms of translating ‘sustainable intensification’ goals into reality and some see a move to total confinement systems as inevitable. However, initial results of this review highlight there are still considerable benefits of incorporating pasture grazing into production systems. Ultimately this is more than a scientific question, with the choice of system depending on individual circumstances, ethics, policy and personal views on the meaning of ‘sustainable intensification’.
By Dr Gareth Arnott, AgriSearch research fellow in international dairy production at Queen’s University Belfast Institute of Global Food