Tropical Pasture Trials at Waikato Innovation

Pasture trials have been carried out at Barlovento, a soy and maize farm in the region of the Llanos Orientales in Colombia. The trials were based on work done in Brazil. They have determined that the tropical grass Tifton 85 (a type of Bermuda grass) is best suited as the basis for a pastoral NZ-style farming system in Colombia. A New Zealand dairy nutrition consultant, Paul Sharp, has been involved in running the trials from August to December 2011. Results indicate impressive results in dry matter production, high protein levels and low non-digestible fibre content.

Tifton85 is a grass bred in Georgia, USA. The pasture trial forms part of a larger development by a group of New Zealand companies under the management of Dairy Solutionz based at Innovation Waikato. The pasture trial is a new concept for Colombia. It is the first time anyone has planted and managed tropical grasses for use in a pastoral farming system in this country. The concept was inspired by the efforts of Owen Williams in Brazil. Owen is involved with the design team in Colombia along with Paul Sharp, and Paul Bardoul (a high-input system dairy farmer based in Waikato).

Paul Sharp is a nutrition consultant and dairy farmer, as well as being a specialist in forage agronomy. He is based in Pukekohe but has spent many months in Colombia, designing the trials and evaluating results. Paul first went to Colombia two years ago and the pasture trial was run over 4 months from August to December 2011.

There is little seasonal variation in the Llanos region, with temperatures ranging from the mid-20s to high 30s. There is a dry and a wet season, with annual rainfall about 2.5 metres. For three months of the year (December to March) rainfall is below 15mm per month.

Challenges exist in transferring a pastoral farming from NZ to Colombia. They include the temperature (which is right on the edge of dairy cow tolerance), soil composition, growth rates of grass and subsequent requirements for modifying pasture management practices.

The trials were set up at Barlovento, a farm owned by the Aliar Group. Like most of the farms run by the company, it primarily produces soy, maize and pork. The farm was selected for the trial because it is flat, accessible and has power and water. The nearby pig-finishing unit also provides a ready source of fertiliser.

The trials also considered the impacts of soil, pasture and animal interaction – a particularly New Zealand approach to pastoral farming.

There were 7 varieties of grass considered as a pasture base for the Llanos region. Andres Felipe has been working with Paul Sharp and was responsible for running the trials on site. He is a Colombian who is the project manager for the new farm at San Francisco (and first employee of WaikoAliar). He spent time in New Zealand over May and June on a couple of NZ dairy farms to look at best practice farms here.

One aim of the trial was to identify the best performing grass as well as the optimal management system. Tropical grasses tend to produce high quantity but low quality forage. They are also generally high in fibre, with very little protein or carbohydrate/sugar content. However these forage trials have shown the potential to lift protein content and reduce fibre levels in tropical forages. In particular, Tifton85 has demonstrated a relatively low non-digestible fibre content with protein contents suitable for milking cow – a big plus.

The trials looked at the effect of different frequencies of grazing/cutting the grass on protein and fibre content. It was confirmed that pasture composition changed depending on how the pasture is managed.

The trials were carried out on a scale large enough to assess commercial potential. Plots of 1,000 square metres were replicated three times for each of the seven grasses under consideration.

Grasses were harvested at different times using a Colombian version of Gallagher forage harvester equipment to cut and weigh wet weight. Samples were sent to a University in Bogota, and ARL (Analytical Research Laboratories, a wholly owned subsidiary of Ravensdown) in New Zealand, to be analysed for protein and fibre, yield and quality.

Tifton85 produces 280kg DM/ha/day. In comparison, the best of Kikuyu grass grows at about 200kg DM/ha/day, while ryegrass pastures in New Zealand may grow up to 120kgDM/ha/day for short periods of time.

Modelling indicates a stocking rate of 10 – 12 cows per hectare would be required to maintain pasture quality (compared to 2.5 – 2.8 cows per hectare typically run in the Waikato region).

To compensate for the lack of carbohydrate content in the grass, it is planned to supplementary feed with maize silage (which contains 40 – 50% carbohydrates). Maize is grown locally to supply the piggeries, so is a low-cost supplement option in Colombia.

Paul Sharp, Paul Bardoul and Owen Williams are members of the technical design committee for the trial. They’re also involved in the design of the dairy farms to be created in the three joint ventures.

The next step of the trials is to put livestock on Tifton85, initially a mix of Brahman and Holstein or Jersey cows, over the next few months.

Propagation of the grass involves cutting and spreading the stolons. It is possible to increase coverage ten-fold every three months. The limiting factor is getting the stock on fast enough to control pasture growth. Due to the grass’ rampant growth rates, pasture will be cut to waste initially.

One limiting factor is the pH of the soil, which is quite acidic at pH levels between 4.2 and 4.3. A major capital outlay is the application of calcium carbonate (lime) required to counteract the natural acidity.

Regular applications of fertiliser (NPK) will have to be made to support the pastures in the Llanos. The grazing system will be similar to New Zealand’s but grasses will be left slightly higher to maximise nutrients produced.