Wagyu Nutrition: The Magic of Marbling through the Science of Feeding

Part One of our Wagyu Nutrition Series

While Wagyu are genetically predisposed to develop marbling, the science of feeding helps Wagyu reach their full marbling potential. To develop the sensational marbling King River is known for, we lean on the expertise of Nutritionist Dr. Robert Lawrence to tailor the design of our feeding program. With a doctorate specialising in cattle, two degrees in rural science and decades of experience, Rob has been working with the founding King River families for 23 years. Since the launch of King River, Rob has been working with the team at the Lotus Park feedlot to ensure our Wagyu receive top-quality nutrition throughout their growth and maturity, are monitored closely and have every opportunity to produce stunning and consistent marbling.  

Growing and Finishing 

The sole focus in a normal cattle feedlot is finishing, but with Wagyu, there are two distinct feeding phases: growing and finishing. Why are two phases needed? One key characteristic in Wagyu – marbling – only develops after the animal reaches full maturity. While other cattle can be slaughtered earlier in life, Wagyu must be supported throughout their growth and maturity to produce sensational intermuscular marbling. 

The growth phase of feeding is about supporting the Wagyu’s body to maximise its skeletal development before it starts to mature. The size of the Wagyu is primarily determined by genetics, but great nutrition will ensure the Wagyu has the health and support to grow to its full size, maximising the size of our final cuts. In the growth phase, the young Wagyu eat smaller portions, so we look to maximise nutrient-dense food and fibre to encourage a healthy digestive system rather than promote fat. 

Once the Wagyu almost reaches maturity, it’s time to transition to the finishing diet. In this phase of the Wagyu’s life, the emphasis is energy expressed as fantastic intramuscular marbling. One of the challenges for Wagyu feeding is that they need time in their maturity phase to develop marbling, so they can weigh up to 700kg by the time they are slaughtered. This takes a large amount of energy-rich food to ensure the Wagyu maintains weight. Not providing enough energy will result in lost marbling as the cattle begin to burn body fat. 

Adding to this complexity, the Wagyu will naturally eat less as they reach mature weight. We ensure optimal marbling right through to slaughter in several ways: 

• Wagyu are fed high-energy grains, so every feed supplies the body more than their energy they output. 
• Ample fibre is included to support the liver, stimulate rumination, promote lower blood pressure to avoid sore feet. Healthy hooves are the foundation for keeping the Wagyu mobile, well fed and hydrated.
• The Wagyu are given organic zinc with chromium, an essential trace mineral to support their insulin. 
• Betaine from sugar beet is also included in the diet to help the muscles hold onto moisture. This is particularly important in summer as it ensures the Wagyu don’t need to work as hard to stay cool and hydrated on warmer days.  

The importance of breeding and the first 200 days

Marbling is formed through naturally occurring fat cells embedded in the muscle that begin to fill up during the finishing phase. These fat cells are developed before birth and in the first 200 days of the cattle’s life. So, while finishing creates the marbling, breeding and rearing are responsible for the biological markers that determine each Wagyu’s potential. 

King River’s breeding program uses highly scientific measures to breed strategically for high-marbling cells. Once born, the young Wagyu have 200 days to finish developing. Unfortunately, Wagyu heifers don’t naturally produce high amounts of milk, so King River supports the development of calves with creep feeders as a supplement. Creep feeders, placed in the paddocks with Wagyu calves, are high in protein, minerals and starch and encourage the development of the Wagyu’s fat cells. 

Monitoring for optimal results

Monitoring Wagyu in the feedlot is critical for determining animal health and the timing of diet transitioning and selection for despatch. A number of assessments combine old-fashioned measurements and visuals with scientific software called MMEF (multiple maintenance energy factor). 

King River aims to minimise stress to the animals in two ways: through doing all assessments as the Wagyu enter the feedlot, and then by visual assessment. On arrival, King River will measure the cattle’s frame score (hip height) to help predict the eventual skeletal size. Once in the feedlot, the King River team will use visual assessments to determine general health, when to transition from the growth phase to finishing, and to monitor fat deposits. As the final stage of fat development is around the ribs, visual assessment helps ensure cattle are processed after reaching their full marbling potential. 

Lotus Park also uses MMEF to predict the animal’s live weight. MMEF helps provide a scientific measurement to establish when the Wagyu are eating above their maintenance requirement. This is key to accurately and sustainably developing beautiful Wagyu marbling. 

By meticulously balancing genetics, nutrition, and scientific monitoring, King River ensures every Wagyu achieves its full marbling potential. Our dedication to this process guarantees that each cut of Wagyu beef from King River is consistent, beautifully marbled and has the exceptional quality and flavour our clients love.