Reducing purchased concentrates with improved silage quality
By Teagasc’s Seán Cummins and James Fitzgerald
Grass silage falls into second position – only behind grazed grass – as the most consumed feedstuff on calf-to-beef farms.
Depending on farm location, it can be the main forage source available to animals for between 100 and 150 days over the winter months.
The 12 participating farmers in the Teagasc Green Acres Calf-to-Beef Programme have worked to improve the quality of the silage available on their farms this winter.
Overall, silage quality has improved due to the implementation of plans on: budgeting; closing and cutting dates; pre-closing management; fertiliser; and harvesting/preserving.
First-cut silage quality
Analysis has been completed on the silage made on the participating farms during the summer of 2020.
In terms of silage quality, there are a number of key metrics that require noting. Although a basic silage analysis will provide a host of information on the feed value and the preservation of a silage, the most important element in quality terms is the dry matter digestibility (DMD) of the silage; this is directly linked to energy value – usually the first limiting element in beef diets in Ireland.
At farm level, the DMD of silages produced on the Teagasc Green Acres farms did climb in 2020 when compared to 2019.
An average DMD of 74.4 was recorded this year, which compares favorably to the 72.3 DMD recorded in 2019. In addition, improvements were also witnessed in terms of crude protein content (+0.7%) and the metabolisable energy (+0.3MJ/kg).
Impact of improved silage quality
Although the two-unit rise in DMD may seem small, the additional improvement in silage quality can have a big impact on the meal feeding levels required to reach the desired levels of weight gain over the winter months in calf-to-beef animals.
Ideally, weanlings entering a steer or heifer finishing system need to gain a minimum weight gain of 0.6kg/day over the winter months. In many cases, this is achieved through silage and concentrate diets.
In terms of finishing diets, the improved quality silage will result in the meal feeding requirements required to achieve 1kg/day over the finishing period for Holstein Friesian steers falling by 1kg/head/day (5kg versus 4kg). Over a 100-day finishing period, this equates to a saving of €27/head (€270/t meal cost).
Overall, the reduction in meal feeding on account of the improved quality of silage is worth approximately €3,500 to a farmer carrying 100 Friesian weanlings and 100 Friesian finishing steers over the winter months.
On-farm improvements – Shane Cranny
Shane Cranny farms 40ha of grassland in Myshall, Co. Carlow, where 70-80 autumn-born calves are purchased and carried to beef annually.
As the system is predominately focused on autumn calves, the requirement to house finishing stock over the second winter is all but eliminated. On account of this, first-cut silage is targeted at yearling autumn-born animals to ensure they achieve the desired levels of weight gain over the winter period.
Shane has made vast improvements in his silage quality, with DMD, ME and crude protein all rising. This change occurred due to an earlier harvesting date in 2020, with first-cut silage saved in the second week of May, two weeks earlier than 2019.
With the earlier cutting date, Shane has seen the portion of stem present in the silage reduce significantly and, as a result, DMD value climbed by 4.2 units.
Given the quality of first-cut silage present on the farm this year, Shane can reduce his meal feeding rate to the yearling animals back to 0.5kg/head/day, down from 1.2kg/head/day over the winter of 2019 – a reduction of 5t of meal over the winter period.
Martin Connolly, who farms part-time just outside Castleplunket in Co. Roscommon, runs a calf-to-bull-beef system on 60ha where he buys in 120 spring-born, dairy-bred male calves and brings them through to slaughter at approximately 22 months-of-age.
Over the last couple of years, Martin’s silage quality was below par mainly due to the harvesting dates being too late.
The heavy nature of the ground he farms along with high levels of rainfall in the springtime resulted in him not being able to get his silage ground grazed off in time to close it up in early April.
As a result, closing and harvesting dates for the first and second cuts were delayed by over a month, substantially reducing silage quality.
This year, the first-cut silage ground was fertilised in mid-March having been grazed tight with weanlings at the end of the 2019 grazing season. The first-cut was harvested on May 11 and returned a result of 76.4 DMD – an improvement of 13.3 DMD units on 2019.
As Martin is operating a bull-beef system, his concentrate input is going to be higher than those required for steer or heifer systems over the first winter, with an average daily gain of 0.7-0.8kg targeted.
On account of the improved quality of first-cut silage available in the yard, and taking into consideration an average winter length of 120 days, the Roscommon-based farmer stands to see his meal inputs reduce by approximately 14.5t this winter.