46. Metabolisable Energy in Ruminant Nutrition - it’s an interesting topic, we promise!

A fundamental basic of ruminant nutrition – energy density of feeds – is covered in this latest Rumen Room Podcast.

Expressed as Megajoules of Metabolisable Energy per kilogram of dry matter (MJME/kgDM), energy density is an important driver of animal productivity and profitability.

In a down to earth, practical “gumboot level” manner, Dr Charlotte Westwood explores the basics of MJME as a concept and covers how feed testing laboratories measure MJME. How we use MJME values of a feed on farm on a day to day basis is explained. The strengths and possible limitations with the use of MJME in our day to day farm-level decisions is discussed.

Don’t be put off by what is often thought to be a rather "dry" topic of MJME - actually, it’s a straightforward concept - we’re sure you’ll learn a lot from this latest podcast!

Here’s where to find the various sections within the MJME podcast, below:

2.02 Outline of this MJME podcast

3.40 What is “energy”?

6.30 Defining Megajoules and Metabolisable Energy

7.50 Megajoules compared to Megacalories – what’s the difference?

10.25 What is gross energy and why might we be interested?

14.25 Why ruminants can’t use all of gross energy in feeds for useful things

15.10 Faecal energy – what a waste! (#1)

16.10 Digestible energy

17.25 Methane – what a waste! (#2)

18.10 Finally arriving at the MJME number…. How this is calculated

19.00 How different feeds change energy losses as methane

21.00 Measuring MJME – inside the sheep

23.00 Feed testing laboratories estimates of MJME

25.40 Using the digestibility value to calculate MJME

26.20 NIRS technology - digestibility and MJME

31.15 Strengths and weaknesses of MJME as a measure of feed quality – an overview

32.00 Typical MJME values of feed

34.40 Valuing our feeds on a cents per MJME basis – a simple task on farm! Valuing a bale of pasture baleage on an MJME basis as an example

38.00 Using MJME as part of your feed budgeting – MJME demand vs. MJME supply. A 30kg liveweight lamb as an example

40.30 Limitations of MJME as an indicator of suitability of a feed for animals

41.30 MJME is a calculated measure only!

42.00 MJME doesn’t tell us about all of the other interesting stuff in feeds

44.10 Summing up the MJME topic