Show Notes

Today we discuss the bigger part of how you make money on the farm - how well you feed the animals. Nutrition of your livestock is one thing that you can get right, or wrong, on a daily basis; genetics is a longer burn. With nutrition, you can see the results almost immediately. To discuss this, our guest this week is Charlotte Westwood.

Charlotte got her vet degree from Massey University and spent the first years of her career in the Waikato working mainly with dairy cattle. After a back injury, Charlotte headed off to Australia to do a PhD looking at cattle reproduction.

Now, Charlotte is a Veterinary Nutritionist at PGG Wrightson Seeds and the focus of her chat with Mark today is intramuscular fat (IMF). 

When we talk about the genetics of IMF, the words “Wagyu” and “Angus” come up, and it’s often considered to be predominantly genetics that influence levels of IMF. Charlotte explains why that’s not the case. She also explains why it’s a longer game than you might think. 

“The bizarre thing is, we think [the influence around IMF is] about the [nutrition] weeks or maybe a couple of months before the animal is processed,” explains Charlotte. But it starts much, much earlier than that. “A lot of what is happening, when the animal reaches its finished stage for processing, has actually started whilst still inside mum's tum.”

Charlotte explains what “The Marbling Window” is.

“The nutrition of mum in that last trimester can influence both the number and also the potential for the future growth of the fat cells within the muscle itself. So if mum has a hard time during the last trimester of pregnancy, that may influence the decision of stem cells - whether they’re going to turn themselves later into muscle, fat or fibre cells. There’s a drafting gate there and if we don't get it right inside mum's tum, in a small way that can influence IMF deposition.”

Charlotte runs through how fat is laid down in an animal once it’s growing, and it’s quite fascinating.

“Fat is laid down in a specific order. You've got your internal, visceral fat... then they'll move onto all subcutaneous fat around the body. When that starts to get laid down, they move on to the fat that's laid down between the muscles.... and then the final stage of fattening is when the animal's older, through maturity typically, or getting close to its mature live weight, then IMF gets laid down.”

IMF is the last to be laid down, and unfortunately it is the first to go. Charlotte explains. “When animals hit stress for any reason [...], enough to go through a short period of negative energy balance, they'll start to mobilise fat. And they'll mobilise it out in the order it was laid down. So that IMF you've lovingly sculpted… for a sake of a period of stress, the IMF is the first to peel out.”

If you’d like to hear more from Charlotte, she has her own podcast, The Rumen Room, where you can listen to episodes on the basics of nutrition, reproduction and much m


Head Shepherd is brought to you by neXtgen Agri International Limited, we help livestock farmers to get the most out of the genetics they farm with. Get in touch with us if you would like to hear more about how we can help you do what you do best - info@nextgenagri.com

Thanks to our sponsors at MSD Animal Health and Allflex and Heiniger Australia and New Zealand.

These companies are leaders in their respective fields and it is a privilege to have them supporting the Head Shepherd Podcast. Please consider them when making product choices as they are instrumental in enabling us to bring you this podcast each week.

Check out Heiniger's product range HERE
Check out the MSD range HERE
Check out Allflex products HERE

Comments & Upvotes

Listen On