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How Can Robots Work With Grazed Systems?

08 April 2014

Can automatic milking systems in grazing operations be feasible? Dr Bernadette O'Brien and Dr Cathriona Foley, two Teagasc researchers, reveal their current study looking at how to manage grassland and automatic milking.

Dairy farming in Europe has adopted automatic milking (AM) at an accelerating rate, particularly in Western Europe (Jago, 2011), write Drs O'Brien and Foley. The main reasons for this are improvement in lifestyle, reducing physical work, difficulty in attracting skilled labour, increased profitability based on higher milk production (within high input systems) and lower labour costs.

This trend is increasing and it is envisaged that up to 20 per cent of cows in Europe will be milked automatically by 2020. However, while indoor feeding systems have been well adapted to AM, cow grazing systems have not.

In order for AM to become a realistic alternative to conventional manual milking in Irish grass-based systems, the practical challenges of integrating AM and grazing must be researched.

AM has the potential for advancement in precision dairy farming, e.g., to improve automatic data collection, providing herd managers with data that will enable them to make effective management decisions, and focus on strategic tasks that are economically beneficial.

Farm System Description

A milk production system trial was put in place at Teagasc Animal & Grassland Research and Innovation Centre, Moorepark, Co Cork.

Seventy Friesian, Jersey-Friesian and Norwegian Red breeds averaged 4,222 litres in 2013

The dairy features one Merlin 225 AM unit (supplied by Fullwood for research) installed adjacent to the existing shed. The farm-let associated with the AM system consists of a 24ha milking platform.

The system has 70 spring-calved cows of Friesian, Jersey-Friesian cross and Norwegian Red breeds. The land area is divided into three grazing sections of 8ha each (A, B, C), which are further divided into 1ha paddocks.

Four main roadways radiate from the centrally located dairy. Water is located at the dairy. The maximum distance to the furthest paddock is approximately 750m.

The infrastructure incorporates a pre-milking waiting and post-milking area. There are three drafting units, two positioned at the entrance to the dairy that draft cows to the pre- or post-milking area depending on readiness for milking, and a third positioned at the dairy exit, which drafts cows to a holding yard or to grazing.

Grazing Management

The grass allocation is critical to optimal cow visits to the AM unit (it can influence too frequent or infrequent cow visits).

Cows graze defined areas or portions of each of the three grazing sections during each 24-hour period. Cows may be allocated, for example, 5kg DM in each of the three grazing sections (A, B and C) over each 24-hour period. Cows are moved between the grazing Sections A, B and C at 8am, 4pm and midnight, respectively.

During the May/June period cows go into grazing areas with grass covers of 1,400-1,500kg DM/ha. Grass covers greater than 1,500kg DM/ha would discourage cow movement to the AM unit and may reduce milking frequency. Cows graze to a post-grazing height of 3.5-4.0cm. Cows are stocked at an average of 3.5 cows/ha. All cows receive approximately 1kg concentrate/day during the main grazing season. 

Ongoing progress An average milk yield of 4,222L and milk solids yield of 369kg per cow was achieved during the 2013 lactation. Even though 34 per cent of the herd were 1st lactation cows, this level of milk production is still comparable with a large proportion of Irish dairy farms.

Total milk volume and milk solids produced by the AM unit were 263,529L and 23,112kg, respectively. The average number of milkings per day was 104, ranging from 70 to 123 per day in the March-to-August period.

The average number of milkings/cow per day was 1.8, ranging from 1.6 to 2.1. An average milk somatic cell count of 152,000 cells/mL was observed, while average total bacterial counts were at 10,000 cells/ mL in the same time frame.

To Optimise Cow Milking Frequency

A main objective of this study is to investigate the effect of milking frequency on milk production characteristics and cow traffic. In a grass-based system, it is important to focus on the total output of the AM system rather than the output per cow.

Thus, a trial was designed to answer the research question whether fewer cows with a relatively high milking frequency and milk yield, or a higher cow number accompanied by reduced milking frequency and lower per cow milk yield, resulted in a more profi table system.

A preliminary trial was carried out in autumn 2013 (September 1-20). Cows were randomised into two groups of 35 cows each and two milking frequency treatments (approximately 1.5 and 2.0) applied to them.

This was achieved by allowing cows to be milked if their predicted milk yield (at the time of the cow visit to the AM unit) was >50 per cent and >33 per cent , respectively, of their daily yield (averaged over the previous 10 days).

Although these milking frequencies were significantly different (1.4 and 1.9 times per day), the milk yield per day (13.4 and 13.7kg/cow/day, respectively) was not significantly different between groups. This study now will be repeated over the complete lactation period in 2014.

Next Steps in AM Research

The practical challenges to integrating AM and cow grazing include: initiating cow movement to visit the AM unit; queuing of cows for milking; achieving high utilisation of the AM unit; and managing a seasonal calving pattern involving a peak milk yield period. The grass allocation was critical to optimal cow visits to the AM unit.

Overall, the integrated AM and grazing system operated satisfactorily, but significant further research is required. The economic viability of AM will determine how widely the technology will be adopted.

A major challenge with automatic milking currently is the high capital cost but the concept of combining automatic milking and cow grazing has potential advantages, which could have a positive impact on the dairy industry in Ireland in the long term.

These include: reduced labour input; management tasks as opposed to manual labour; ability to expand cow numbers on fragmented land bases; and increased knowledge of cow performance data to use as a management tool.

However, considerable research needs to be conducted to establish if the concept presents a realistic alternative to conventional milking systems on dairy farms. The fact that cow grazing systems have not been well adapted to AM has led to a decrease in grazing on farms with AM across Europe (Van den Pol-van Dasselaar et al., 2011).

This is an undesirable trend, since grass-based systems of animal production are becoming increasingly competitive. Allied to this is the positive impact on milk quality and reduced environmental footprint associated with increased quantities of grazed grass in the diet, as well as increased animal welfare standards. Thus, the desire to research the integration of AM and cow grazing both in Ireland and other EU countries has led to a current three-year FP7 funded EU project (coordinated by Ireland) (AUTOGRASSMILK), which commenced in January, 2013 (

Planned outputs include: protocols for optimum feeding strategies; pasture management tools; sustainability assessment tool; and a web-based decision support tool to optimise economic efficiency of AM in grazing scenarios. This research has received funding from the European Union’s Seventh Framework Programme.

April 2014

Jago, J. (2011) ‘Automatic milking - is it an option for small to medium herds in NZ?’ Primary Industry Management, 15(3): 19-21. Van den Pol-van Dasselaar, A., de Vliegher, A., Hennessy, D., Peyraud, J.L. and Pinxterhuis, J.B. (2011) ‘Research methodology of grazing.’ Proceedings European Grassland Federation Working Group on Grazing. Report 405. Lelystad, Wageningen UR Livestock Research, 19 pages.

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