The quicker and more cheaply beef cattle reach sale weight, the more profitable they become when they can only ever gross around £1400 per head depending on the market.

That is the overwhelming viewpoint of from Robert Logan of SAC Consulting, who says newly weaned growing cattle still have good feed conversion, but this lessens with time. A young growing animal may convert at 7:1 but this rises to nearer 14:1 in the final stages of finish.

"That is why, in forage based rations, it is important to know the quality of silage when planning winter feeding, to make cost effective decisions on concentrate supplementation," he said.

And while cash flow is generally quite tight, he was keen to stress that 'the only thing more expensive than poor silage is assuming it’s average,' which is highlighted in the table below.

Figure 1

Scenario 1 2 3

Average silage, Poor silage, Assumed average

0.8kg DLWG 0.8kg DLWG but actually poor,

0.4kg DLWG

Grass silage Ad-lib Ad-lib Ad-lib


(inc minerals) 2.5 4 2.5

Cost per kg of gain £1.40 £1.80 £2.60

Based on silage at £25/t and concentrate at £250/t

The table shows that nearly 2kg more concentrate maybe required feeding poor quality silage compared with average quality to achieve the same levels of daily liveweight gain.

However, the most expensive scenario (No 3) is where forage is assumed to be of reasonable quality but is actually of poor nutritional value, compromising growth rates resulting in a higher cost of liveweight gain. Cattle then need to be kept for longer or alternatively, sold at lighter weights. Either way result in reduced margins irrespective of how this is measured – per animal/per shed space/per labour unit/per acre, Robert said.

Using the above scenario 3, for a shed of 50 growing cattle would result in 3600kg less liveweight growth over 180day winter compared to scenario 2, which is around £7500 in reduced sales from the shed.

“This makes a silage analysis, time for rationing, cost of supplementary feeds and even the purchase of weigh cells look like a good buy. Knowing how cattle are performing on the ration, firstly by analysing forage, rationing, promoting intakes and then weighing cattle is increasingly essential, particularly with expensive feeds this winter," concluded Robert.

Fundamentally Different Silages

Grass silage samples being submitted to the SAC Consulting laboratory are significantly different on the year. This is unsurprising but particularly true for first cuts.

The same farm, which might more regularly analyse silage dry matter at around 22-25% are returning results nearer 35%DM reports Mary McDowell, ruminant nutritionist at SAC Consulting.

She notes that for all beef and sheep samples, first cut silage analysis has averaged 33%DM but last year they averaged 25%DM. That’s around 10kg fresh weight of difference between this year and last year if feeding a suckler cow to appetite.

Feeding grass silage-based rations to the same quantities as last year could result in a significantly different outcome.

Cows are in generally very good condition across much of the country and feeding without managing silage stocks, risks cows being fat, not fit, at calving, especially considering these silages tend to be more palatable and voluntary intakes will be good.

In addition to dry matter, there has also been a large spread in silage quality. Figure 2 is a summary of SAC Consulting Analytical Services silage analysis for all samples received. It shows the spread of metabolisable energy (ME) and what proportion of the silages have analysed at compared to last year, 2017. The ME ranges from 8 to 12.3 MJ/kgDM.

The chart shows that there is a slightly higher proportion of high quality (12+ ME) silages compared to last year. Client discussions at an individual beef farm level have been most frequently about dry and marginally higher energy silages, particularly in first and single bulk cuts, Mary said. However, the averages shown in the table reveals a slightly different message, presumably averaging slightly lower energy overall if some producers delayed harvest in the hope that it would bulk out; cutting a more mature crop. The key is that each farm is different and most likely different on the year, and that is important for rationing cows and calves.

This year, a lot of producers did manage to fill the forage gap by catching a late cut of silage in autumn. Generally late season silage tended to have lower energy and protein levels than first cut, therefore, you will find you need to adjust your rations accordingly as you move onto these silages too. Mary concluded that the relatively low cost of a silage analysis will save farm businesses money and improve animal performance if then used to tailor rations.