The Rumen Room Podcasts cwestwood

Sliced on our morning cereal or perched on top of our iconic New Zealand dessert Pavlova, kiwifruit deliver a tasty powerpack of valuable nutrients for us humans. What about ruminants? Are reject kiwifruit from your local packhouse equally as good for our dairy cows and other animals on farm? Yes! A valuable source of energy delivered largely as water soluble carbohydrates, whole kiwifruit can be a very useful feed.  However… as for any byproduct feed, kiwifruit may not always meet our expectations as a stockfeed.
Join us for this latest podcast that explores the good, the bad and the (occasionally) ugly aspects of kiwifruit as a feed for ruminants, with a specific focus on kiwifruit feeding to lactating dairy cows.
Although this is a kiwifruit-focused topic, we include content that applies equally to the feeding of other byproduct fruit and vegetables. Enjoy!
Where to find the various topics within this podcast:
2.35 Overview of the episode
5.35 The nutritive value of kiwifruit – “so changeable as the fruit ripens”
6.45 Water soluble carbohydrates (WSC)
7.45 Neutral detergent fibre (NDF)
8.30 Crude protein (CP)
10.40 Ash and mineral content
13.10 Risk of rumen acidosis associated with kiwifruit feeding
19.00 Best practice approaches to minimise risk of rumen acidosis when feeding kiwifruit
20.30 The importance of knowing your kiwifruit on a dry matter (DM) basis - and not just a wet weight basis
21.35 Gradual adaptation by ruminants to a kiwifruit diet
22.40 The protective role of a rumen-full of long stem fibre in reducing risk of rumen acidosis
23.10 Day to day consistency when feeding kiwifruit is the key!
23.50 Maximum daily amounts of kiwifruit you can feed to dairy cows. The answer? “It depends”
25.05 Feed planning with kiwifruit – the “Three Versions” of a diet that contains kiwifruit
27.30 The role for Kiwi ingenuity and innovation when feeding kiwifruit
33.15 Handling kiwifruit storage on farm
34.00 What to do if kiwifruit is overripe?
35.00 Are rumen additives protective against kiwifruit-induced acidosis?
37.00 Risk of “choke” and rumen bloat with kiwifruit feeding
41.00 Know how much your kiwifruit are costing you. Converting $ per tonne wet weight to $ per tonne DM
44.15 The paperwork. Dairy Feed Declaration. Making sure your kiwifruit are fit to feed
45.45 Preventing birds from eating your stockpiled kiwifruit, helping out your local Regional Council.

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

Our latest podcast explores DCAD - one specific aspect of the diet of “springer” (“close-up”) dairy cows.
The Rumen Room Podcast has briefly discussed DCAD previously (Episodes 10 and 34).  Changing the DCAD of a springer cow diet potentially reduces risk of hypocalcaemia (low blood calcium) in cows before, during and immediately after calving.
This latest episode takes a deeper dive into the detail of DCAD, explaining what DCAD is, what stock class stands to benefit the most from changing dietary DCAD, and how dietary DCAD influence risk of hypocalcaemia. Practical approaches to DCAD management for pasture-fed cows are covered and options for dietary DCAD additives are investigated.
Location of topics within our latest podcast.
1.00 DCAD as just one aspect of the springer dairy cow diet.
1.45 Introduction to the DCAD podcast
4.55 The definition of DCAD
5.45 Dietary cations and anions explained
6.45 The four dietary elements contributing to DCAD: Potassium, sodium, sulphur and chloride
7.50 The DCAD equations – there are a few out there, we like “equation 1” for calculating DCAD
9.10 How does changing DCAD work? DCAD simplified!
10.50 What’s the “ideal” DCAD for springer diets?
11.35 How long should springer dairy cows be exposed to low or negative DCAD diets before calving?
12.55 DCAD once a cow has calved
14.41 How slight changes to blood pH reduce risk of hypocalcaemia  
22.00 High potassium ryegrass (and other types of feeds) and DCAD in springer diets
23.40 Ryegrasses can accumulate lots of potassium!
24.42 Whey applied to pasture as a risk factor for high potassium and high DCAD pastures
25.45 Lucerne silage, baleage or hay and DCAD and calcium in springer diets
27.25 Sodium as a driver of DCAD for New Zealand pasture-fed springers
28.35 Lower DCAD feeds for springer diets – Maize (corn) silage
30.40 Additives that change the DCAD of springer cow diets
35.30 “Do no harm when trying to solve a milk fever problem” – the risk of reducing feed intake by springer cows when unpalatable / not very tasty anionic products are added to diets
37.45 Negative DCAD additives that also deliver calcium: Calcium chloride & calcium sulphate
40.35 Measuring DCAD of feeds – the role for feed testing and springer cow urine testing
43.20 Concluding / summing up the DCAD podcast

Our latest podcast carries on with our heat stress 'theme' from episode 43, where we explored the challenges of hot temperatures on pasture species.
We’ve moved the theme of heat stress across to how heat stress effects dairy cows. We discuss how heat stress bothers cows, and investigate strategies to reduce the effects of summer heat on lactating cows of hot summer temperatures.
Featuring expert heat stress guest podcaster, Lori Grinter, this episode covers a wide range of heat-related topics. Lori first explains how her heat stress studies as part of her Masters undertaken at the University of Kentucky uncovered different cow responses to heat stress, and gave industry new insights into how cows respond to hot weather.
The remainder of the podcast returns very much to a New Zealand-based discussion around how heat stress influences lactating cows, and farm-level strategies that reduce the heat load on our cows.  
If you’re short on time listening to our latest podcast, here’s where to find the various discussion sections:
1.46 Introducing guest heat stress podcaster, Lori Grinter
3.05 University of Kentucky heat stress research completed by Lori
4.12 Cows voluntarily taking a cool shower (we kid you not!)
9.10 The 5 hour time delay between exposure by cows to heat and cows seeking a cooling shower
12.45 “THI” the temperature humidity index defined – knowing when conditions are hotting up
15.15 Signs that our cows show us, when they’re getting hot and bothered
17.00 The rumen heat chamber – high fibre feeds and heat stress
17.20 Rumen acidosis risk, as worsened by heat stress
22.15 Shady dealings – The importance of shade for keeping cows cool
28.55 Exercise – hotting things up, the importance of walking and moving cows during cooler parts of the day
32.20 Cow nutrition – Concepts for keeping cows cooler during hot conditions
40.45 Cool clean stock water – a critical factor when managing hot cows
44.10 Cow wearable technologies – useful things to monitor for early signs of heat stress
47.00 Resources for learning more about hot and bothered cows
Below are the links for Lori Grinter’s publication in the highly esteemed Journal of Dairy Science
https://www.journalofdairyscience.org/article/S0022-0302(19)30151-1/fulltext
https://www.journalofdairyscience.org/article/S0022-0302(22)00677-4/fulltext
(Note that this heat stress study made editors choice!)

With the New Zealand summer in full flight during early 2024, it’s timely to review how hot temperatures potentially alter the dry matter yields and nutritive value of our temperate pasture species.
Exploring first how hot temperatures impact dry matter yields (kilograms of dry matter grown per hectare per day), the podcast looks at effects of hot weather on New Zealand’s most common pasture species combination, perennial ryegrass (Lolium perenne) and white clover (Trifolium repens). Other species discussed include continental (summer active) tall fescue (Festuca arundinacea) and cocksfoot (Dactylis glomerata, otherwise known as orchard grass) and red clover (Trifolium pratense).
Nutritive value of temperate pasture species, as influenced by hot temperatures is covered, looking specifically at digestibility and MJME, as well as NDF, NDFd and non-structural carbohydrates as influenced by hot temperatures.
A note that we make within this podcast is that the selection of pasture species should never be made simply on the basis of heat tolerance, in isolation from other factors to consider. Multiple factors also requiring consideration include soil fertility, pH, rainfall/irrigation, and paddock aspect - to name but a few factors other than heat tolerance. Talk with your local PGG Wrightson Seeds agronomy expert for all the information you need around your regrassing requirements.
Various sections within the podcast can be found below. Hope that you find this topic a "cool little topic" to tune into (pun totally intended). Happy listening! 
 
0.55 Introduction
1.39 Overview of the content of our latest podcast
2.05 Scene set – Overview of New Zealand pastures (for the benefit of our non-New Zealand based listeners)
3.40 The wide range of pastures from the north to the south of New Zealand
6.35 Dry matter yield by pasture species when hot summer temperatures arrive (along with other factors including moisture deficit)
8.35 The “ideal” daytime temperatures that support optimum growth rates by our temperate C3 pasture species?
9.50 How hot is too hot for our temperate C3 pastures? Perennial ryegrass, continental tall fescues & cocksfoot
10.05 How hot does it need to be before perennial ryegrass gets hot and bothered?
10.40 Tolerance to temperature by tall fescue compared to perennial ryegrass
11.45 Adequate moisture allows C3 grasses to better tolerate hot temperatures.
14.10 Cocksfoot tolerance to hot temperatures and moisture stress/dry conditions compared to perennial ryegrass 
15.50 The role for endophytes in perennial ryegrass and tall fescue and tolerance of heat 






17.25 How frequent irrigation helps temperate grasses handle hot temperatures – “transpiration” and evaporative cooling
20.00 **Don’t select a temperate grass species ONLY on the basis of heat tolerance, there are so many other factors to consider when moving away from perennial ryegrass as you core grass species.**
22.30 Legume (clovers, lucerne) growth during hot weather
23.40 Chicory handling hot conditions – but only if adequate moisture is available
25.40 Nutritive value of temperate pasture during hot weather – changes to digestibility, MJME, NDF and NDFd
30.50 Digestibility and NDF changes by tall fescues and perennial ryegrass as summer temperatures increase
35.55 Legumes – changes in nutritive value with hot temperatures 
39.50 Legume quality changes over summer – not related to grazing management and temperature 
40.20 More clovers in pastures swards – the rumen bloat conundrum
42.35 Temperate grasses - Non-structural carbohydrates (water soluble carbohydrates and starch) changes with temperature
43.30 Temperate legumes - Non-structural carbohydrates changes with temperature
48.50 Recap / conclusion of topics covered

Thiamine (Vitamin B1) deficiency - a nutrition/diet-mediated animal health condition sometimes seen in ruminant species - features in this, our latest Rumen Room Podcast. Most often seen in young, spring-born ruminants during their first summer of life, thiamine deficiency is a sporadic animal health condition that most New Zealand dairy, sheep and beef farmers will be familiar with.Featuring five sections packed with information about thiamine, Dr Charlotte Westwood steps us through this podcast in a down to earth, practical manner. Thiamine as a vitamin is defined and clinical signs of thiamine deficiency are discussed – the “neurological” form of deficiency (Polioencephalomalacia, sometimes called "polio", "PE" or "PEM") and the “Ill-thrift” form of deficiency.  Why all ruminants are not equally at risk of thiamine deficiency is explored. How your vet will likely help you with dealing with thiamine deficiency is covered. Strategies that can reduce risk of thiamine deficiency in New Zealand ruminant species are suggested.
*Note* The information about thiamine contained in this podcast episode is NOT intended to replace the expert advice from your own veterinarian. If you have any concerns about animal wellbeing and/or underperformance by your ruminant animals, please contact your own veterinarian.