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Silage - Both a Cost and an Asset, so why should Farmers know it’s True Value

08 November 2019
Type Media Article

By John Galvin, B&T Drystock Adviser, Teagasc Galway/Clare

November is the normally the start of the “official” winter in the west though due to the high levels of rainfall and poor ground conditions we have experienced through September and October, many farmers had no recourse other than to house cattle much earlier than normal.

Grass silage is the primary source of winter forage in the form of round bales or pits, with 1st cuts, 2nd cuts and surplus grass from fields making up the feed stocks. Consequently the quality of silage may vary considerably which is a reason for concern. Silage being fed to animals may not be adequate to match their nutritional requirements. As a conscientious farmer, you should have confidence in the quality and nutrition value of your animal’s feed to maximise their performance and your profits.

To date in 2019, Teagasc has tested just over 250 silage samples. The results of these tests clearly indicate that the majority of farmers do not know the nutritional value of their silage, although there is anecdotal evidence that many farmers are becoming more pro-active in this regard getting tests carried out through feed merchants and co-ops. Simple on-farm assessments can be carried out to establish dry matter, preservation levels and feed value using our senses of sight, touch and smell but these are only a guide at best. In most farms accounts, silage making will rank as one of the largest annual expenditures, it is an integral part of the farming business and therefore deserves due attention.

The most important quality criteria when it comes to analysing silage feed value is the Dry Matter Digestibility (DMD) as grass crude protein and minerals generally parallel it. The DMD value is used to estimate the energy contained in the silage as well as expected live weight gains/milk yields and for planning meal supplementation rates.

Table 1:

Target Silage Quality
Autumn Calving Cows 75 DMD
Spring Calving Cows 65-70 DMD
Young Breeding Stock 70 DMD
Finishing Animals 75 DMD
Weanlings & Stores 75 DMD

Spring Calving Suckler cows are in good condition in general this year with ample supplies of grass throughout the summer grazing period and if they are fed to appetite on 65 DMD silage, there should be no issue. First and second calvers however require more care; ideally they should be penned together and fed 70 DMD silage/65 DMD + 2kg meal.

To achieve a positive margin in the beef trade this winter will prove very challenging both live in the marts and for finishers at the factories. However the principles and advice for best practice should not change: farmer’s feeding weanlings, stores and finishing animals require high quality silage. I understand there may be the argument to feed your cattle to appetite on silage only without detailing the quality of the silage largely due to perceived cost restrictions but as farmers, you should be aware it is more cost effective to operate with this knowledge. The optimum daily gain for a weanling/store is 0.60kg/day; any more comes at too much of an added meal cost unless the animal is suitable for a very high end export market. If the animal is gaining < 0.5kg/day it will lead to a stunting effect due to a protein deficiency and having a poor weight for age will make an animal much less attractive in a mart ring.

Table 2:

Good Silage Vs Poor Silage
Diet for 300kg weanling/store (Silage fed ad-lib)Expected Liveweight GainCost per Animal per DayBreakeven Price Required(To cover feed only) 
70 DMD Silage + 1Kg Conc’s 0.60kg/day €1/hd/day €1.66/kg
60 DMD silage + 2.5Kg Conc’s 0.60kg/day €1.25/hd/day €2.10/kg
60 DMD silage + No Conc’s 0.20kg/day €0.84/hd/day €4.20/kg

This table above illustrates how ineffective and costly poor quality silage is in the diets of young growing cattle. Furthermore the cost associated by both the added concentrate supplementation and/or the thrive penalty associated with feeding inferior silage are just too high for it to be financially feasible. For finishing cattle there is equally no place for inferior quality silage. A typical continental steer within 100-120kg of finished weight needs to be fed ad-lib 75 DMD silage + 4-5kg of high energy concentrates to gain 1kg LWG per day whilst to achieve a similar weight gain on 65DMD silage would require double the input of concentrates and at that level ad lib concentrates feeding should be considered. Indeed savings can be made especially when feeding dry suckler cows with 70-75 DMD silage, they can be restricted to 80% of intake which equates to almost 2 bales per cow over the winter period.

Testing your silage makes good financial sense and makes for better husbandry. It costs around €35 per sample with a report of detailed results returned within a week. To accurately test your silage, take a fresh sample from the middle of the pit or a representative sample from a number of bales and mix it up in a clean bucket. Place the sample in a large freezer bag, keep cool and dispatch to the lab as soon as possible. Ideally test the silage at the start of the week to avoid transit delays over the weekend. Contact your local Teagasc office for more information.