So, what is the FVI and how does it work?
The FVI is a profit-based index for shorter-term and perennial ryegrass cultivars. It’s simply a number we calculate for each cultivar, much like Breeding Worth for cattle. However, the value of FVI for a cultivar is in dollars a hectare ($/ha).
FVI is calculated based on how well the cultivar performs in the National Forage Variety Trial (NFVT) in terms of seasonal drymatter yield and what value the additional yield has on dairy farm operating profits at that time of year. While the New Zealand Plant Breeding and Research Association (NZPBRA) administers the NFVT under strict protocols, DairyNZ independently analyses the data to produce the FVI results.
To make cultivar selection decisions even easier, we have converted each cultivar’s $/ha FVI, into one of five ‘star rating’ categories. Cultivars contributing the most to dairy farm operating profits receive five stars, while those giving the least get one star.
This is much like the five-star accommodation rating system, except unlike booking a five-star hotel, you won’t be left with a gaping hole in your wallet. Although the FVI doesn’t include the additional seed costs of choosing a particular cultivar, it does give you an idea of the relative benefits you might get.
Benefits from choosing a higher star-rated cultivar can be substantial and over the long term, can far exceed the cost of the seed. In the upper North Island, for instance, a five-star cultivar is expected to contribute about $540/ha more each year than a one-star cultivar. Furthermore, this does not take into account benefits from using high-quality seed. Nor does it include the potential benefits of improved quality of the herbage grown in a new pasture. But while the pasture quality aspects of the cultivars are not yet accounted for in the FVI, this will be the next trait to be included.
Waikato 50:50 sharemilker Aaron Price is a perfect example of the new breed of farmers routinely consulting the FVI before choosing new cultivars.
Price, 29, from Tahuna, won the Best First Year Pasture in the Waikato-Bay of Plenty Pasture Renewal Persistence Competition last month. He has a strong interest in pasture renewal, in regard to the long-term economic impact on the farm.
He says he always chooses a diploid ryegrass for its persistence value and endophytes NEA2 or AR37 for best pest resistance in Waikato conditions. He generally bases his decisions on whatever cultivar the FVI indicates will provide the best economic return for the time of year concerned. Aaron’s winning pasture was a mix of Trojan perennial ryegrass, Kotare and Weka white clovers, Safin cocksfoot and Tuscan red clover.
An important issue raised by farmers is persistence and the view that some of the new cultivars don’t persist as well as the older cultivars.
DairyNZ’s principal scientist Dr David Chapman presented analysis of long-term herbage yield measurements at last year’s NZ Grassland Conference. He and his co-authors indicated that in a long-term trial at Poukawa in Hawke’s Bay, cultivars that performed well in the first three years tended to perform well in later years. This supports the practice of using three years of trial data from the NFVT for the FVI.
Finally, it is important to remember that choosing the best ryegrass is not the start and finish of your pasture renewal decisions. Using the FVI is just one of several steps you need to get right to avoid below-par results from pasture renewal. Others include:
Assessing the value of pasture renewal for your situation
Selecting and preparing the appropriate paddock
Selecting the right cultivars, using the FVI and expert advice
Sowing the paddock for optimal establishment
Managing the pasture so that high performance cultivars can achieve their genetic potential.
More information on pasture renewal is available at dairynz.co.nz/pasture. To make a more informed cultivar selection decision this autumn, get on a computer or smartphone and check out the DairyNZ FVI website dairynz.co.nz/fvi.
Cameron Ludemann is DairyNZ’s forage value manager.
