Making dairy feed efficiencies pay

Dairy farmers in Canada finally have a genetic index for feed efficiency after it was added to Lactanet’s genetic evaluations for Holstein cattle in April.

With feed costs rising, and feed accounting for more than half of on-farm production costs, the farmer-run organization is taking a closer look at adding feed efficiency to the Lifetime Profitability Index (LPI) and Pro$ calculations.

LPI and Pro$ (pronounced pro dollar) are bundles of genetic indices that farmers use as an evaluation for the overall quality of the animal in question.

But adding feed efficiency to LPI and Pro$ isn’t as straightforward as other evaluated genomic traits.

At Lactanet’s Virtual Industry Open Session Oct. 14, Gerrit Kistemaker, manager of genetic evaluations gave an overview on how the organization may express feed efficiency in LPI and Pro$ terms.

Feed efficiency in dairy cattle is a measurement of how well a dairy cow can convert feed into milk. In a paper published by Lactanet on its website, feed efficiency (FE) is measured by looking at the difference between how much you think an animal will eat, compared to what they actually do consume.

“A cow that eats less than expected, without losing body condition or decreasing production, is more efficient. Using this idea, we can account for the differences in feed consumption we see between animals due to their production level or body weight — and target true metabolic feed efficiency,” said authors Caeli Richardson, Lactanet’s genetics expert on its Innovation and Development team, and Brian Van Doormaal, chief services officer.

Evaluating feed efficiency isn’t straight-forward as other traits as numerous biological mechanisms in the cow are involved. Richardson and Van Doormaal said that it requires in-depth, detailed records on many characteristics, the most important being daily dry matter intake (DMI). Daily measurements on individual cows is labour-intensive, however with recent genomic advancements and by collaborating with other countries in a five-year study, they said Lactanet is now able to provide a relative breeding value (RBV) for feed efficiency.

The global project was undertaken in order to bring enough resources together to be able to gather enough data and share costs, due to the intensive nature of feed efficiency evaluation in dairy cows.

Currently, Lactanet uses daily feed intake and body weight data collected on individual cows in various herds, including three in Canada, eight in the US, and three others internationally.

“This allows us to accurately measure the cow’s individual feed intake and then consider the energy required for maintenance and production,” said Richardson and Van Doormaal.

Feed efficiency RBVs are available for Holstein females enrolled in Lactanet DHI herd and for genotyped bulls in A.I., and the organization is now ready to consider adding them into LPI and Pro$ formula indexes.

Before this can happen, Kistemaker said the biggest question that needs to be answered is how should feed efficiency be weighted? Feed efficiency is not strongly correlated with most of the key traits evaluated by Lactanet, such as fat and protein yield, conformation, milk yield or lactation persistency.

This weak correlation works for the approach that Kistemaker wants to take, as it is independent from body size and other traits. He suggests expressing feed efficiency in a dollar form, and then adding it to Pro$.

“As long as we express feed efficiency in dollars in the correct way, we can simply add it,” he said.

His suggested approach is to quantify the economic value of feed efficiency by using known, verified data on dry matter intake and the conversion of feed to energy in dairy cattle for up to five lactations.

Overall, he estimates that over five lactations, feed efficiency evaluations reduce DMI by 53 kg per five (FE)RBV points. Every one-point (FE)RBV increase in feed efficiency in a sire’s proof is expected to reduce feed cost in daughters by $9.43. This calculation evaluates the lifetime of the cow, from birth onwards. Kistemaker said Lactanet knows that this number is lower than it should be, as peak lactation is not accounted for, and many cows do not live long enough for five lactations.

However, it’s a good estimate to use for animals that currently have a feed efficiency evaluation. If animals do not have a feed efficiency evaluation, they can be assumed to be average and no adjustment needs to be applied.

Expressing FE in the LPI is not as simple, he said, as the LPI is not expressed on a dollar scale. He said the LPI is approximately 40 per cent of the Pro$ scale, but has a much narrower range and less variability than Pro$. By taking 40 per cent of $9.43 (which equals 3.77), Kistemaker said this number can be used to estimate the change in LPI.

While Kistemaker cautions that these numbers are conservative, adding FE to the LPI and Pro$ does have economic value.

“I think everybody realizes that feed intake is a big cost endeavour on the farm,” he said.

Kistemaker suggests that FE be added to the indexes in April 2022, after a full year of data collection has taken place. The advantage of his approach is that if feed costs change and more animals are evaluated, the feed efficiency values for Pro$ and the LPI will reflect this.