The Rumen Room Podcasts

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

45. Dietary Cationic Anionic Difference (DCAD) – One strategy for reducing challenges of low blood calcium in dairy cows

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

44. Hot and bothered lactating dairy cows - the how, the why and what we can do to help our cows

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!)

43. Hot and bothered summer pastures – less dry matter and poorer nutritive value for your grazing ruminants

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

42. Thiamine deficiency in sheep and cattle – a nutritional challenge with an animal health twist

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. 

41. Internal parasite management– the role for good nutrition (plus many other parasite topics!)

Our latest episode features guest speaker Dr Ginny Dodunski who joins Rumen Room host Dr Charlotte Westwood for a chat about all things internal parasites. As a New Zealand-based veterinarian and self proclaimed “gumboot parasitologist”, Ginny requires little introduction to most kiwis involved in farming. With a background in veterinary practice, farm consultancy and more recently, working part time with Wormwise, Ginny joins us to cover a range of topics relating to internal parasite management in sheep and cattle.
Given the concerning scale of resistance by internal parasites to our range of anthelmintic (drench) products, Ginny steps us through a range of down to earth, practical recommendations to managing internal parasites – including the important role for top quality nutrition for maternal and young stock.
Anyone who is involved in managing young stock should tune in - there will be some  practical tips and tricks for everyone.
Have a scroll (below) through the content for our latest episode featuring Ginny Dodunski. 
0.50 Ginny’s background and how her passion for all things animal health, and how her journey working with internal parasites began.
6.05 The timeline of New Zealand resistance since the days of effective anthelmintics
7.00 The cost of internal parasites (including resistance issues) to the New Zealand pastoral industries - and at the level of individual farms
8.40 The novel drenches, Zolvix™ Plus (monepantel and abamectin) and Startect® (derquantel and abamectin) help uncover the true cost of internal parasite resistance in lambs
9.50 Picking up sub-clinical internal parasite challenges (or not!) – especially when other autumn health challenges are occurring
12.10 Who to talk to if you suspect internal parasite resistance issues at your place
13.45 Is my drench working or not? Faecal egg counts
15.15 Starting the internal parasite journey – starting with the ewe/lamb(s) unit
16.25 Higher lambing percentages and internal parasite challenges (and opportunities)
18.40 Well fed ewes support good lamb weaning weights, reducing numbers of lambs on farm post-weaning
22.40 Anthelmintic treatments for ewes pre-lambing (or not)
24.10 Ewe nutrition and body condition– building tolerance to internal parasites
28.35 Hatching and development rates of larvae – differs for eggs from ewes and lambs
30.20 Ewe stocking rate combined with other stock classes – optimising ewe nutrition
32.50 Three Pillars of Parasite Management
33.30 First Pillar = well fed, healthy robust breeding stock
33.35 Second Pillar = young stock on clean feed (less worm larvae than average hill country pasture)
34.40 What’s the best crop for lambs? 
37.45 Feeding lambs the best quality feed that you can – the Third Pillar
38.10 Gross margin analyses on forage crops – understates the value of crops for young stock
39.00 Preparing pasture areas to finish lambs on – integrating cattle with sheep
40.00 100kg calves (dairy replacements, dairy beef) and internal parasites
43.00 Buying in 100kg calves – cautions around risk of parasite resistance
44.20 Holding young stock in yards to empty out after quarantine drenches
46.30 Faecal egg counting in young cattle – usefulness for different ages of cattle
48.40 Trace elements / trace minerals and internal parasites
52.05 Where to go to learn more about internal parasites

40. The role for dietary iodine in dairy cows before and during mating

This episode takes a deep dive into the topic of dietary iodine requirements of cows - and the relationship (or not) of iodine intake with the reproductive performance of cows.
Iodine is well down the priority list when tackling challenges of poor reproductive performance. Body condition score at calving and the extent and duration of body condition loss (‘negative energy balance’) are by far the more important factors that drive successful reproductive outcomes in dairy cows.
That said, iodine features every season in conversations on farm about improving mating outcomes. “Iodine improves expression of heat by cows” has been around for a long time as a topic of conversation. Fact or fiction? Join us in this latest podcast to explore the potential relationship between dietary intake of iodine by cows (and some discussion of ewes too) and the wellbeing of ruminants.  
As always, the content of this podcast is of a general nature only and is never intended to replace the advice of your very own local veterinarian and qualified dairy nutritionist.
Where to find different parts of this podcast:
1.20 Overview of the topic of iodine and the reproductive performance of pasture-fed dairy cows
1.55 Iodine might play a possible role in cow fertility but more than 100 other factors determine if cows will mate successfully – particularly cow body condition score at calving and extent and duration of body condition loss between calving and mating
5.00 Iodine increases expression of signs of oestrus (heat) by cows – fact or fiction?
7.45 Why do cows require iodine in their diet? It’s all about thyroid hormones, needed particularly by the unborn calf.
9.30 What do thyroid hormones do inside the cow (and unborn calf) or indeed inside the ewe (and unborn lamb)
12.00 Goitre in newborn calves and lambs – very rarely seen in adult stock
14.10 Aside from clinical signs in newborn animals born to cows and ewes, there’s not much to see in iodine deficient cows and ewes
16.40 Iodine and the functionality of the reproductive system in cows
17.00 The “HPO” axis that drives reproductive function and the role for iodine
18.45 Possible changes to reproductive function when iodine status is low
22.30 The challenges of diagnosing iodine deficiency in cows (but discuss this topic further with your vet)
25.15 Pasture levels of iodine are very variable!
25.50 Salt spray off the sea – adds small amounts of iodine to pasture
26.30 Other factors that influence iodine intake by pasture-fed cows
27.05 Goitrogens in forage feeds – reduced conversion of iodine to thyroid hormones 
29.05 Types of goitrogens in NZ forages
31.50 Iodised teat sprays and iodine status of lactating dairy cows
33.25 Taking the simple approach, not testing for iodine, can we just add iodine to the diet?
33.55 Care with supplementing with iodine, some countries, upper limits to iodine supplementation!
34.20 Selenium deficiency contributes to thyroid hormone challenges as well

39. Summer forages for lactating dairy cows. The Mark and Courtney Harris story

With the ever-increasing inconsistencies of summer weather impacting on dryland dairying, forage crops deliver a valuable bulk of high-quality summer and early autumn feed. In our latest dairying-themed podcast, host Charlotte Westwood is joined by Waikato dairy farming couple, Mark and Courtney Harris - to learn of their investigations into the fit of different summer forage crops for their dairy business.
Farming across two properties in the northern and southern reaches of the Waikato, summer crops form an important feature of Mark and Courtneys dairy systems. Chicory and summer brassicas are cost effective feeds for their herds, helping to to offset the absence of sufficient quantities of high quality pasture that would otherwise compromise summer milksolids production.
Mark and Courtney discuss how four years of on-farm work that has compared cow responses to either chicory or summer brassicas has taught them much about the fit of summer crops within their dairy business.
Which is better as a summer forage crop for cows? Chicory or brassicas? Which crop type should we plant? Tune in, Mark and Courtneys findings might surprise you.

38. Feed for your stock - Spring planting decisions; “What’s In the Bag” – with agronomist Brian Young

With spring planting coming up fast for us here in New Zealand, our latest episode focuses on decisions around choosing the right pasture and forage crop seeds.
Host Charlotte Westwood chats with guest podcaster, Southland agronomist Brian Young about all things seeds. Brian’s background includes farming (sheep and beef, and dairy), shearing, working as a rural retail rep and, for the last 9 years, working with PGG Wrightson Seeds, advising farmers how to grow the very best pastures and forage crops.
What’s involved in choosing the right type of seed? Just what is in that bag of seed?? How do we know that the seed will be right for us, will grow lots of feed for our stock, and won’t bring in unwanted weeds? Brian steps us through the information we need to make informed choices when choosing the right seed for us.  
There’s a bit of info for everyone in our latest podcast.

37. Setting ewes up well through lambing – Pasture-based tips and tricks

This episode carries on from Episode 36, expanding the topic around feeding ewes well through lambing. First up, we cover off on the challenges of stress, and of pre-existing animal health conditions on the ability of a heavily inlamb ewe to look after herself and her unborn lambs well, from a nutritional point of view. The importance of getting stocking rate right at the point of set stocking is discussed, and we investigate ways to calculate what your stocking rate should look like. Lower than ideal pasture covers at the time of set stocking - such a challenge! Short and longer terms ideas of improving pasture-feeding levels at lambing are discussed.
Content of our latest podcast:
1.50: Feeding ewes well; more kg of lambs weaned per ewe mated
3.00: Non-nutritional factors that impact on the nutritional status of ewes in late pregnancy
4.20: The role of stress in late pregnancy; Weather, yarding, disrupting lambing ewes, pre-lambing shearing too close to lambing
7.30: Internal parasites and nutritional status of ewes
10.20: Illness and injury – risk of ewe undernutrition
12.15: Ewe body condition score (BCS) and ewe nutritional wellbeing through lambing
17.35: Working to improve ewe BCS at lambing – a longer term view
19.45: Pregnancy scanning – An incredibly valuable tool in managing ewe nutrition
22.00: Setting the stocking rate for twin/triplet-bearing ewes at set stocking, prelamb
25.50: Beef and Lamb FeedSmart – just one of many tools available to define ewe nutrition through lambing
33.10: Feeding ewes well vs. risk of bearings
36.00: Managing pasture deficits at set stocking; (a) Short term strategies
39.10:  Managing pasture deficits at set stocking; (b) Longer term strategies