GROW, GRASS, GROW
Record rainfall levels will present fresh challenges for Taranaki dairy farmers in making next year’s feed reserves of hay and silage. The wet start to spring across the region, has meant that it has been very difficult for Taranaki’s dairy farmers to conserve feed and make silage, says Lauren McEldowney, DairyNZ consulting officer for North Taranaki.
As a result, she says, farmers are at least two weeks out in their traditional timing for the season.
‘‘The balance date – where pasture growth rate per hectare equals feed demand per hectare – is later than usual and farmers are at least two weeks behind where they would be normally,’’ says McEldowney.
‘‘This means that there is going to be a smaller window for farmers to shut up paddocks for silage and harvest feed prior to Christmas. If the current wet weather conditions carry on, silage yields may be lower than what is needed for the following season.
‘‘For most farmers, average pasture covers are lower than where they would normally be for this time of year. Pasture utilisation is very poor due the continued wet conditions, and a large quantity of feed is being pushed into the ground by cows.
‘‘There is also a larger amount of pasture damage than normal, which is leading to lower growth rates on the damaged areas. Because of wet ground conditions, it has also been more difficult to apply fertiliser, which is also impacting on the feed situation.
‘‘Most Taranaki farmers had used all their conserved feed (from last year) by the end of September. This is certainly due to the wet conditions and possibly a follow on from last year’s wet winter/spring.’’
Depending on the exact location of the farm, McEldowney predicts that it will likely be around this latter half of October before farmers can get their first cut of grass for silage.
Despite the setback due to the weather, farmers should not panic, she warns.
‘‘Farmers need to make sure they don’t worry about trying to get the ‘right’ or ‘target’ amount of hay and silage bales or tonnes this year. If the grass isn’t there, then surplus isn’t there. Trying to make silage when there isn’t surplus, risks under-feeding the herd. The dollars saved can be diverted into other priorities including purchasing feed.
‘‘Farmers will need to make more accurate and timely decisions around feed budgeting and drying off.’’
It is impossible to make good quality silage from poor quality pasture, advises McEldowney.
‘‘When silage is well preserved, losses in energy content during fermentation will be minimal and the final silage will be only slightly lower in energy than the original pasture it was made from,’’ she says.
‘‘The original pasture must be leafy, highly digestible, and contain high concentrations of both metabolisable energy (ME) and crude protein. Silage should be cut before it reaches a cover of four tonnes of dry matter per hectare, in other words, harvesting 2 to 2.5 tonnes dry matter per hectare.
‘‘The longer silage paddocks are shut, the lower the energy content will be. Heavy silage crops have a lower energy content and the paddocks are slower to recover.
‘‘It is best practice to take little and often, as this silage is of better quality and the paddocks are brought back into the round more quickly.
‘‘To minimise losses during harvesting, silage should be cut after one to two sunny days and shouldn’t be wilted for more than 24 hours. This will result in good sugar levels in the pasture. The optimum dry matter per centage for pasture silage is 25 to 30 per cent. To ensure minimal losses during the
fermentation process, the dry matter per centage should be between 25 and 30 per cent and the stack should be completely sealed so that air cannot get in. (Source: DairyNZ website, SIDE 2017 proceedings Kerr & Montgomery). Good quality grass silage is not far
short of good quality maize silage in terms of ME value, says McEldowney. ‘‘ME value of grass silage compared to maize silage depends on quality of feed ensiled, the ensiling process and storage. Good quality pasture silage will have an energy value (MJME/kg DM) of 9.5-11. Poor quality pasture silage will have an energy value (MJME/kg DM) of 9.
‘‘Maize silage with a high grain content will have an energy value (MJME/kg DM) of 10.8 – 11. Maize silage with a low grain content will have an energy value (MJME/kg DM) of 10 – 10.5.
‘‘The rules and processes for making good silage haven’t changed much over the last 20 years. The main difference is that in the event of poor silage making conditions (less than ideal wilting conditions), there are now inoculants available to assist the fermentation process, whereas 20 years ago these were not widely available.
‘‘Obviously, as time moves on, we get more information and science on best practice and how to improve our management.
‘‘The most common mistakes made now in processing silage are a lack of rolling and consolidation and poor covering of the stack. This is because the volumes of harvested grass arriving at the stack is faster than in the past and less time is available to consolidate and cover the stack properly than in the past.’’