Media release: Making silage from pugged paddocks - DPI guide
Wednesday 10 August 2011
Making silage off pugged paddocks this year will be a challenge for many Victorian farmers. Experts from the Department of Primary Industries (DPI) have prepared a series of guidelines to help farmers and contractors conserve fodder this season.
DPI Pasture and Fodder Conservation Specialist Frank Mickan said damage to pastures will vary according to how wet the soils were at grazing, pasture cover at grazing, soil type, stocking density, follow-up rain events and - in particular - the actual grazing management.
"Here are some principles to keep in mind," he said.
Silage fermentation: Mud, dust and silage do not mix. Undesirable bacteria will be incorporated into the silage stack or bale and are highly likely to cause poor fermentation. This will result in relatively high losses of dry matter and nutritive value of the silage, which will vary in palatability from ‘not nice’ to ‘inedible’.
Silage additives: Although no guarantee of success, the use of fermentation enhancing-type silage additives is highly recommended this year. There are many products that achieve the same outcomes but bacterial inoculants are a major group in this category.
The addition of the desirable lactic acid-producing bacteria (fermentation-enhancing inoculants) will help to some extent, to compete against the spoilage bacteria in the mud/dirt/dust that will inevitably be picked up during raking or via forager/baler tynes.
Also, silage additives will increase the likelihood of a more favourable fermentation under the possibility of poor wilting conditions (cool, overcast weather). The forage being ensiled may be slightly under the minimum target levels 30 per cent dry matter for forage harvested silage, or under 40 per cent for baled silage.
Note that the additive application rate is on a fresh weight basis so higher rates of additive will have to be applied than if the material was harvested at the recommended dry matter (DM) contents. Farmers and contractors will need to accurately determine the throughput of their harvesting machinery to apply the correct rates.
Wilting rate: To speed the rate of wilting, use a tedder as soon as possible after mowing, and possibly again the next morning, after the dew has lifted. Set the tedder and rake tynes to clear pug marks to avoid picking up too much dirt in the forage.
Soil acts as a 'bad' inoculant and can contaminate much of the stack or bale. A flail-type mower conditioner with swath boards left as wide as possible will also increase the wilting rate, although at reduced rate compared to a tedder.
If possible harvest only the cleaner areas of the paddock and avoid the odd low lying, wet or muddy areas.
Pasture quality: Pasture quality starts deteriorating once pastures approach canopy closure. If this occurs, sunlight will not reach the pasture base and the growth of new tillers will be greatly reduced and also cause the death or weakening of fledgling tillers. As a result pasture regrowth will be less dense, and ultimately, result in lower total pasture production.
In mid to late spring ryegrass plants could be at the two to two-and-a-half leaf stage of growth when canopy closure becomes an issue.
If the plants are still in the vegetative stage, either in early spring or with later maturing varieties, then the drop in nutritive value will be reasonably slow.
However, if ryegrass tillers are starting to become reproductive (stems contain seed heads), then canopy closure will be reached more quickly causing the above problems. More importantly, pastures with seed head emergence stage decrease in nutritive value much more rapidly than those in the vegetative stage.
Paddock choice: Are there less wet paddocks that can be ensiled whilst trying to graze the wetter paddocks, using on-off grazing?
Another option if pugging is not likely to be too much of a problem, some of the wetter paddocks may be able to be grazed on a fast rotation and then grazed quickly again within a week or so.
This will reduce pasture growth and set back regrowth a few weeks while providing some feed but may allow harvesting them later, and for any drier paddocks to be harvested earlier and being of higher nutritive value.
Due to a quicker grazing in these paddocks, they may have higher residuals and may need to be post-graze topped when conditions suit, if they are not ensiled. They may be of lower quality.
Pre-graze topping may be another option but remember that milk production may drop somewhat as the animals won’t be able to select and will consume the good, the bad and the fouled.
Media contact: Sue Webster, DPI Ellinbank, 0402 267 802