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