Net Feed Intake Fellowships available for AWA members

Receive $10,000 to support implementation of NFI recording infrastructure

Net Feed Intake (NFI) is a measurement tool used to assess the efficiency of feed conversion in animals. It is calculated by measuring the total amount of feed consumed and comparing this to the amount we would expect to be consumed given the growth and maintenance energy requirements of the animal. Energy requirements for maintenance vs growth.

When feed is not available to animals, they loose weight very quickly. This is due to the constant energy requirements to fuel the body. We only see this energy demand visibly, when feed is limited and animals start to lose weight and body condition. The energy requirements of the body are constant (every day) and must be met before any feed energy can be used for gain of body weight as added bone, muscle and fat.

Larger animals have larger bodies with more kg of bone, muscle and fat. Larger animals require more energy to maintain their bodyweight compared to smaller animals. The following figure is from a review article of Cabezas-Garcia et al. (2021) Animals 11(6); 1642;

The red curved line through the centre of the four published models in Figure 1, is the average relationship between liveweight and maintenance energy requirements (MEm) for non-pregnant and non-lactating cattle. This demonstrates that a 500kg animal (e.g. a growing steer), requires approximately 56 MJ/day to maintain its liveweight. In a feedlot feeding a ration of 12 MJ/kg, this equates to 4.7kg of feed.

If the average feed intake of a 500kg steer is 10kg/day, approximately half of its daily feed intake is going towards maintenance. Therefore, of the 10kg eaten, only half is going towards growth of bone, muscle and fat. For non-lactating, non-pregnant females we can compare that a 600 kg animal would require approximately 62 MJ/day to maintain its bodyweight, around 6 MJ/day more than a 500 kg animal.

What is Net Feed intake used for

Net Feed Intake is a weight corrected measurement of feed intake, being the difference between what an individual animal actually eats each day over a typical 49 to 70-day test period, compared to what you would expect it to eat based on its weight, maintenance requirements and its measured growth rate.

Animals with negative NFI are actually more efficient, because they eat less than you would expect based on their weight, maintenance requirements and their growth rate. Animals with positive NFI are less efficient, eating more than expected based on their weight, maintenance requirements and growth rate. Net Feed Intake is used to identify animals that are more or less efficient at gaining weight once maintenance energy requirements are taken into account.

Relationship between NFI and other traits

The following table is adapted from the 2008 R. Bras. Zootec (37: 269 – 279) review publication of Paul Arthur and Robert Herd, two of the leading scientists in the Net Feed Intake research field over the last 20 years. This tables shows the heritability of Net Feed Intake (also called Residual Feed Intake: RFI) and its relationship to other intake and growth traits in Wagyu cattle compared to other breeds. This table shows that Net Feed Intake and Feed Conversion Ratio are both under some genetic control (low to moderate) and that there are positive relationships between Net Feed Intake and growthrelated traits such as Average Daily Gain, Liveweight and Feed Intake itself. So in a general sense, selection for NFI selects for animals that eat more and grow faster. The table also shows that there are significant negative correlations between NFI and rib eye area and carcase marbling score. This means that direct selection for NFI could result in a correlated reduction in eye muscle area and marbling. This is not surprising considering the high energy density of marbling fat within the ribeye and energy requirements for marbling deposition during growth.

Why is NFI a useful tool in cattle breeding

Cattle with a lower NFI are able to gain weight and grow at a similar rate to cattle with a higher NFI, while not consuming as much feed in the process. Animals with a low or more negative NFI are considered more desirable because they require less feed for growth and weight gain, compared to animals with high or more positive NFI. This selection tool is highly valuable to producers, because it allows them to select animals based on their true feed efficiency, allowing them to run a highly productive operation while also cutting unnecessary input costs.

By evaluating this factor, producers can improve their overall herd efficiency and implement feeding strategies that ensure their cattle are getting the right level of nutrition, leading to cost savings and improved efficiency in the herd.

Why the development of an NFI EBV is important for the industry?

The AWA has been actively working with industry partners to capture NFI records for more than five years. There are now around five producers/feedlots with Vytelle NFI bunks recording data consistently. A major focus of the 10-year AWA-PTP is to capture much needed data to create new EBVs and tools for members to make informed breeding decisions into the future.

We already understand that NFI is a moderately heritable trait and is positively related to feeding intake and growth rate. We know from prior literature, that NFI may be negatively correlated with marbling and eye muscle area. Although these correlations are relatively strong, we expect that there will be significant variation in NFI at any particular level of marbling EBV. Therefore, a goal may be to identify animals with high marbling and high eye muscle area genetic potential, that are relatively more efficient (as measure by NFI) compared to other animals with similar eye muscle area and marbling EBVs. Currently, we have close to 2,000 NFI records on registered Wagyu cattle. These records are being used to understand the genetics of Net Feed intake and how this trait relates to other Wagyu traits as measure in our Wagyu population. We are analysing this data now to see if a NFI EBV for Wagyu can be implemented and how this EBV could be used to better inform Selection Indexes to account for individual differences in expression of NFI as a trait through Wagyu production systems.

What is the Wagyu NFI fellowship?

The NFI Fellowship offered by the Australian Wagyu Association (AWA) is a new and innovative grant that provides $10,000 to go towards supporting members in implementing Net Feed Intake recording infrastructure into their operation. Any eligible AWA member is able to apply, with the intention of using Vytelle/ GrowSafe feeders and implementing a four-node or higher number NFI recording system. The grant can be used to complete the implementation of this system (not including capital costs), offset management costs and running costs over a three-year period, to incentivise recording of Net Feed Intake on registered animals. The AWA then would also utilize this data to support the development and implementation of an NFI EBV.

Through a four-node system, a member could run three trials per year of 40 animals per trial, totalling 120 animals per year. If AWA awarded two Wagyu NFI Fellowship grants per year for three years, it would enable cumulative testing of up to 1,440 animals over the three years, leaving an ongoing testing capacity of 720 animals per year.

The AWA is already working with AWA-PTP contributor herds to make them aware of NFI testing and promote the benefits of NFI testing to them. The AWA may prioritise access to the grant to AWA-PTP herds or by members who commit to testing AWA-PTP progeny or large numbers of registered progeny and provision of this data to the AWA.

Our first NFI fellowship recipient – Travis Meade

Travis Meade started with a small-scale Wagyu enterprise and now owns about 180 Fullbloods, 250 commercial Angus joined to Wagyu Bulls and 180 Angus recipient cows. He aims to expand further, hoping to reach 1,000 Fullbloods and continue growing his commercial Angus herd for their F1 operation. Travis's AWA Membership prefix is BEECHY, and his Wagyu herd is named "Beechy Wagyu".

Located in Colac, Southwest Victoria, the property named 'Beeac' covers 4,300 acres of highly productive land and is home to a newly implemented NFI facility. Travis is eager to understand the variations in feed intake and potential ADG of different genetics under a controlled environment, so he chose to use Vytelle NFI bunks. He believes it "will be key in the future, with the current trends towards reducing methane output and its correlation to feed intake."

Although Travis doesn't have the correlation data between NFI and carcase performance yet, he is "very keen to see it; it could be a game changer regarding improving the efficiency of Wagyu cattle". The NFI facility can test roughly 400 cattle annually, and the bunks are fully booked until May 2025. The Beeac facility has already started taking bookings for 2025 from external clients.

Travis's current aim is to test approximately 120 cattle this year (2024) and ramp that up over the next few years. We asked Travis how many make up a pen full for a testing period if members wanted to contact him about getting their stock tested; he answered depending on the sex and weight of the cattle, they can test 40 steers or heifers per pen and when bull testing is conducted, the number is closer to 32 per pen. They currently have two pens, allowing them to test up to 80 animals simultaneously. The total time for animals on the property is 63 days, including a 14-day warm-up period for rumen adaption and a 49-day trial. With the facility fully booked until May 2025, interested parties should get in touch to reserve a spot for 2025 and beyond.