Teagasc is advising farmers to aim for a silage harvesting date of around mid-May, and to close up fields now where possible for harvesting.
John Galvin, Teagasc drystock advisor in the Galway/Clare area, said that, with the challenges faced by farmers due to excessive rainfall impacting silage making, planning silage harvesting becomes even more important.
“It is questionable if it is either sane or appropriate to be discussing the topic of silage making. Yes, there are still large numbers of stock still in sheds and grazing has not gotten into second gear, and indeed it is a common sight to see large trailers of bales being transported on our roads with the winter feeding period going long into extra time,” Galvin acknowledged.
However, he added: “However, plans must be put in place immediately to replenish the much depleted silage stocks on many farms.”
“Every farmer should carry out a simple fodder budget to work out the silage requirements for their farm based on planned stock type, numbers to be wintered and the number of months housed.”
According to Galvin, suckler cows, zero-to-one-year-olds, and one-to-two-year-olds consume 1.4t, 0.7t and 1.3t of silage per month respectively.
A 20-cow farm plus followers housed on November 1 and let to grass on the March 1 gives a silage demand of 272t or 340 bales.
“Quality silage is key in reducing the feed costs associated with cattle rearing in a suckler beef system. Dry matter digestibility (DMD) is one of the key measures of quality, with protein also being very important especially in growing cattle,” the Teagasc advisor said.
The silage quality guidelines for different types of livestock are as follows:
- Autumn calving cows – 75% DMD;
- Finishing cattle – 74% DMD;
- Weanlings and store cattle – 72% DMD;
- Suckler cow in milk – 70% DMD;
- Dry suckler cows – 65%-70%.
Galvin said that, ideally, silage should be cut and harvested in the first half of May as grass digestibility decreases by 2% to 3% units per week from mid-May onwards.
“A leafy sward with little or no stem will typically give 75%-80% DMD silage, while a grass crop with seed heads emerged will normally be as low as 65% DMD. Silage crops need to be walked regularly to monitor growth stage and ground conditions,” he said.
Galvin added: “In my experience, farmers can get too hung up about the requirement to have a crop closed for a minimum of seven weeks due to nitrogen (N) levels.
“There needs to be a greater focus on bringing the harvest date forward to the second or third week of May.”
As the weather is also impacting grass growth, Galvin also advised how fertiliser should be used as a result.
“First cut silage has a requirement of 80 units of nitrogen (N), 16 units of phosphorous (P), 80-90 units of potassium (K) and 15 units of sulphur(S) per acre. I
“Ideally, 3,000gal/acre of cattle slurry would fulfil most of these needs with only 1.4 bags of pro-urea plus S/ac required in chemical fertiliser,” he explained.
“However, this year, with little or no pre-grazing carried out, poor ground conditions and high grass covers, the time for achieving all of the pre-closing best practice measures is quickly diminishing,” he added.
“In this scenario, the crop requirements will have to be supplied by chemical fertilisers in agreement with the farm P allowances depending on soil analysis results.
“If there is no P allowance just spread the required N + S + K and put out the slurry after harvest.”
Some key points Galvin outlined for farmers to remember are:
- Pasture quality;
- Stage of growth of grass at time of cutting (just before seed heads start to appear);
- Do not overload the crop with N, especially old pastures with limited yield potential and un-grazed fields – it delays cutting date and causes lodging risk;
- Ensure not to mow too bare – this risks bacterial contamination;
- Try to mow in late afternoon, when both the sugars and dry matter levels of the grass are at their peak;
- A fast wilt of 24-48 hours depending on mower type and weather conditions is best;
- Avoid delay in harvest especially as there is a 7%-9% quality penalty associated with lodged crops.
“Aiming for the big June cut is false economy. It costs the same to harvest poor quality silage as good quality silage, and this combined with a performance penalty of 50kg-60kg/weanling in the absence of meal supplementation [further increases] wintering costs,” Galvin said.
The advisor added: “Anecdotal evidence from previous fodder shortage surveys suggests that the farmers that delayed their first cut the longest had the largest fodder shortages. Remember late first cut silage means losing out on the May/early June growth rates for second cut crops.”