Suckler Cow Silages for This Winter

With spring calving roughly three months away a key question for beef farmers right now is “what is the body condition scores of my pregnant cows and what is my planned feeding between now and calving going to do to that condition score?”  The aim of the game is to avoid both fat cows with calving and calf viability problems and lean cows with potential problems for colostrum quality, milk supply and future fertility.     

SAC’s Analytical Services Department analyses silages from across Scotland and Northern England and the table below shows a summary of silage analyses for 2018 beef and sheep pit silages with the average figures for 2017 shown as a comparison:

  2018 1st cut  2018 2nd cut Range 2017 average
Dry Matter (g/kg) 332 310 154 - 705 275
D value (%)  66 66 50 - 77 65.5
ME (MJ/kgDM) 10.6 10.6 8 - 12.3 10.5
Crude Protein (g/kgDM) 109 129 64 - 210 107
NDF [fibre] (g/kgDM) 499 469 389 - 656 513
Ash (g/kgDM) 72 83 48 - 118 72.5
pH 4.3 4.3 3.5 - 5.2 4.2


Some general comments are:

  • Not surprisingly this year’s silages are drier than in 2017 with an equivalent digestibility (D value) and energy content (ME)
  • The intake potential of some silages this year is higher as a result of higher dry matter and energy contents, therefore cows will eat more if allowed to
  • The crude protein levels of the second cuts are higher which is a slight increase on the trend of recent years
  • When comparing these results with baled silages for beef cattle the bales average out as drier and have a slightly lower energy content
  • For all of these results the devil is in the detail shown by the range of results seen this year and there is a need for farm specific information 


The table below shows metabolisable energy (ME) intake for a spring calver eating ad lib, that is 1.5% of her live weight (9.75kg dry matter/day) at different silage qualities:

Silage ME (MJ/kgDM)
ME intake per day
Daily live weight gain (kg/day)
10 97 +0.3
10.5 102 +0.42
10.8 105 +0.52

Some key take home messages from all of this are as follows:

  • All these cows are gaining weight if allowed to eat ad lib, good for a few if very thin, but bad for the majority
  • One unit of body condition score is about 85kg for a cow of this size, therefore throughout a winter some cows could gain a whole body condition score
  • Because of higher silage intake potential cows fed restricted silage will finish it up earlier in the day, giving the appearance that they are not being fed enough, even though they are
  • Even when restricted silage is being fed, some dominant cows will eat more and closer to ad lib
  • First calved heifers are likely to be the shyest feeders, have the lowest feed intakes and actually the biggest feed requirements as they are still growing
  • This time of year is a good time to body condition score some spring calving cows to make sure they are still on target to calve down at a target score of 2-2.5
  • An excellent clip on body condition scoring produced by QMS can be found here
  • Do farmers need to re-group their cows and heifers based on parity and body condition score to ensure that the optimum body condition score at calving is achieved?
  • If not done already it is essential to get this year’s silages analysed to know what you are feeding and how much to feed

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