Impact of introducing a herb pasture area into a New Zealand sheep and beef hill country farm system: a modeling analysis

Cory Matthew,Cécile Duranton

doi:10.15302/j-fase-2018202

Cory Matthew, Cécile Duranton

Open Access

https://doi.org/10.15302/j-fase-2018202

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Abstract

New Zealand is well known for export of meat and dairy products from low cost pastoral systems. These farm systems are continually evolving for increased efficiency, in part through the use of metabolic energy modeling tools by farmers and farm consultants to explore alternative farm system configurations and identify new efficiencies. One recent innovation is the introduction of a herb pasture area, such as plantain. We used metabolic energy modeling to quantify seasonal feed flows in two successive years in a New Zealand hill country farm system, and to analyze the impact of the introduction of an area of plantain. Models employed were a self-built Microsoft Excel spreadsheet and a commercial New Zealand farm systems modeling package, FARMAX. Herbage production, animal performance and financial results for a base farm scenario created from the average of survey data for hill farms in the southern North Island, and the same farm with 10% and 20% of the area in plantain for the years 2010–2011 and 2011–2012 were modeled. The self-built model performed similarly to the commercial model. The system configuration of the base farm stockpiles surplus autumn feed for release to animals in winter and also incorporates flexibility that confers resilience to interannual weather variation through varying dates animals are purchased or sold. The introduction of an area of plantain was predicted to increase herbage production, animal performance and financial returns. The predicted benefit was higher for the year 2010–2011 where a drought occurred in summer than for the following year with higher summer rainfall. This demonstrates the profitability of introducing a plantain area to New Zealand hill farm systems, and suggests plantain will assist to mitigate adverse effects of warmer and drier summer conditions associated with current climate change trends.

Highlights

Due to its geological isolation, New Zealand has a unique flora and fauna with some very ancient lineages including the ancient fern-like plant Tmesipteris, the legged velvet worm Peripatus (Onychophora), and the lizard-like Tuatara (Rhynchocephalia)
After first using a pasture growth prediction model and historic weather data to evaluate interannual, weatherrelated variation in feed supply as background to the project, here we: (1) use a self-built metabolic energy model constructed in Microsoft Excel to calculate animal feed requirements in monthly time steps of a typical present-day New Zealand hill farm system, (2) use a commercial farm systems optimization package, FARMAX[5], widely used in farm extension circles in New Zealand, to validate the accuracy of the self-built model results; and (3) we evaluate the impact on the system feed supply and animal carrying capacity of converting 10% or 20% of the farm area to a plantainbased (Plantago lanceolata) herb pasture
In conducting this work we aimed to provide a quantitative insight to seasonal feed supply and demand patterns of a typical New Zealand hill farm system and test hypotheses (1) that system performance as measured by efficiency of conversion of herbage dry matter to meat could be improved by the inclusion of an area of herb pasture in a typical system, and (2) that the self-built farm system metabolic energy model would perform to the commercial FARMAX software

Summary

Introduction

Due to its geological isolation, New Zealand has a unique flora and fauna with some very ancient lineages including the ancient fern-like plant Tmesipteris, the legged velvet worm Peripatus (Onychophora), and the lizard-like Tuatara (Rhynchocephalia). Between 1850 and 1930 much of the original mixed podocarp forest was cleared and sown to pastures comprising typically around 10 grass, herb, and clover species resembling an English meadow[1] (Table 1). With significant transport costs to move goods from New Zealand several thousand km to markets, farmers have had to evolve low cost production systems in order for their products to be price competitive in their export markets. In these systems, the majority of the feed supplied to animals is pasture grazed in situ[4]. The farm profit per stock unit is directly related to the Scenario

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