Agridirect discusses the benefits of grass reseeding and Teagasc's improved Pasture Profit Index for seed varieties. Well folks, it’s time to talk about grass seed. Now I can already anticipate loud scoffing from some small farmers, who think that reseeding is the luxury of the big dairy man. But that’s no longer the case. Numerous studies have documented the benefits of reseeding for dairy and beef production. As previous authors of this blog have pointed out, intelligent reseeding can have enormous long-term economic benefits for farmers. In essence, improved sward quality helps to improve output and save costs. That said, it is important to know what you want from your reseeding. You need to consider whether you are reseeding for silage production or for pasture, as this will have a bearing on what grass seed mix you decide to go with in the end. Now on the face of it, this can seem like a tricky assignment. Fortunately for us, though, Teagasc has already done the research on grass seed varieties and their utilisation. The result is the Pasture Profit Index, which farmers and the seed industry have been using for decades to select the best rye grass varieties. This year, research at Teagasc’s Moorepark premises has yielded a new and important sub-index that will help you to choose the very best grass seed mixtures for pasture paddocks over the grazing season. Below, we take a look at the index, which was presented last month by researcher Tomás Tubritt.
The Pasture Profit Index
The Pasture Profit Index is composed of several sub-indices. Leaving aside the fancy terminology, these indices rate the quality of grass seed varieties on key traits. These traits include spring, summer and autumn grass growth, silage yield and persistence, and autumn herbage. If a seed variety shows strength in a particular trait, that strength translates into a higher economic value on the index. This makes life easier for farmers. It saves the need for a lot of head-scratching and hasty research before making a purchase. Still, though, we have to think about what traits we are looking for, and make our decision based on that.
So you’ve made the decision to reseed. But what do you want from your field?
Before buying, consult the PPI. You should make your variety selections based on the traits that you wish to place greater emphasis on. When choosing varieties, farmers should select based on the intended future paddock use. So, for example, if you plan to put your reseeded field over to silage production, go with seed varieties that score highest on the silage sub-index on the PPI. On the other hand, if a paddock is on a milking platform, and you intend to graze dairy cows there during the grazing season, then you should go with mixes that score highest in the seasonal yield, quality and utilization traits. Now the seed industry keeps up to speed with the research. This means that excellent seed mixes, whether for pasture or silage production, are already available. Here at Agridirect, we sell seed, and seed mixes, that are purpose designed either for silage production or for optimal grazing results. There are also a few seed mixes that boast dual purpose utility (i.e. they are good for both silage production and grazing).
The Grazing Utilisation Sub-Index
As I have already touched on above, the PPI for 2021 contains a new and important sub-index that will help farmers to decide on the best seed varieties for their farms. The Grazing Utilisation Sub-Index identifies those seed varieties that are best suited to rotational grazing practices. What we need to know here is that maximum grass utilization takes place at low post-grazing swarth heights. Ideally, when grazing, you want as much grass as possible grazed, so grasses with high digestibility are the ideal choice for farmers aiming for a rotational grazing platform. According to Tomás Tubritt of Teagasc, “This practice maximizes the grazing of a low cost, high quality feed and stimulates the grass plant to produce more leaf, increasing sward quality. Herbage left behind after grazing will become stemmy into the next rotation, which will lower the sward quality and will then lower the milk production of cows grazing those swards.” Now there are vast differences in the digestibility of grass seed varieties. Cows much prefer to graze certain varieties, and will eat the more digestible ones to a far lower height. Studies across 100 farms in Ireland have demonstrated this conclusively. Cows that grazed on high grazing efficient varieties left low and even paddocks behind them. However, those animals that were put on poor grazing efficient grasses left longer grass swards behind them. So here is where the Teagasc Moorepark research comes in handy. Data gained from Teagasc field research trials of grass seed varieties has enabled researchers to determine the economic benefits of using high grazing efficient, digestible varieties for their pasture. The economic values of the varieties have been converted to a star-rating system on the new index. The more stars a variety has on the sub-index, the better its grazing performance will be.
Thanks for reading
In signing off, let me reiterate: the PPI is an excellent resource for farmers getting ready to reseed. Consult it carefully before making a purchase. The last think you want is to spend time and effort reseeding a paddock for grazing, only to end up with a paddock with poor grazing efficiency. Remember, a little bit of planning today will yield great returns tomorrow (or in a few weeks’ time!). MPG 
