Feed represents more than 50% of the total production costs. Hence, improving the efficiency with which dairy cows convert feed into milk has a large economic value. At the same level of production, cows with reduced feed intake requirements are more profitable. Why some cows need less feed than others of similar body weight and milk production? Probably because they digest feed better, they spend less energy on unproductive activities, and/or they have a more efficient metabolism.
It has been suggested that the US dairy industry could save $540 million per year with no loss in milk production by breeding for cows that are more feed efficient. Residual feed intake (RFI), the difference between actual intake and intake predicted based on body weight and production level, has been proposed as a selection criterion for improving feed efficiency. Research has shown that the top 20% of cows for RFI (low RFI values) compared with the bottom 20% (high RFI values), need 6% less feed to produce the same amount of milk.
Interestingly, the selection for lower RFI, i.e., improved feed efficiency, has the potential to not only reduce feed costs, but also reduce significant sources of greenhouse gas emissions, such as enteric methane and manure.
The major challenge is to collect enough feed intake data on enough cows in order to have accurate genetic evaluations. Measuring feed intake on individual cows on commercial farms is not feasible because of group housing, costs and labor constraints. The advent of genomics in the last decade has facilitated the selection for traits that are critically important, but too difficult or expensive to measure on the entire population, such as feed intake.
Recently, the Council on Dairy Cattle Breeding (CDCB) and the Foundation for Food and Agriculture Research (FFAR) funded a research grant for $2 million aimed to improve dairy cow feed efficiency through genomics and genetic selection. Genomics is a very attractive approach for improving feed efficiency because feed intake phenotypes can be collected for a relatively small number of lactating cows with genotype data, and this reference population can then be used to predict genomic breeding values for the entire population, including young selection candidates.
This project is a multi-institutional effort involving geneticists and nutritionists from Michigan State University, University of Wisconsin, Iowa State University, USDA Animal Genomics Improvement Laboratory, and the University of Florida. Our plan is to measure feed efficiency in about 4,000 dairy cows on research facilities where it is possible to precisely determine individual cow feed intake, body weight, body condition score, and milk energy output.
In addition, we will use new sensor technologies to monitor dairy cows’ body temperature, feeding behavior, and physical activity, along with milk spectral data. These sensor data may be combined with direct observations of feed intake to increase the accuracy of genomic evaluations.
This research project will help to develop reliable genomic breeding values for feed efficiency. Indeed, CDCB plans to start providing genomic evaluations for residual feed intake in 2020 and incorporate this novel trait into the Lifetime Net Merit and other CDCB economic selection indexes.
Therefore, in the near future, US dairy farmers will be able to significantly reduce their expenses by selecting cows with high feed efficiency; specifically, cows that produce the same or more milk while consuming less feed. Importantly, the genetic improvement of environmental sustainability traits, such as feed efficiency and methane emission, is very relevant given the increasing concerns of society about the environmental impacts of dairy farming.
For more information, contact the author, Dr. Francisco Peñagaricano at firstname.lastname@example.org or call (352) 294-6988. Dr. Peñagaricano is Assistant Professor of Dairy Cattle Genetics and Genomics in the Department of Animal Sciences at the University of Florida. This article appears in the September newsletter issued by the Department.
Feed Efficiency Genetics at World Dairy Expo
On Tues., Oct. 1 at World Dairy Expo in Madison, Wis., the Council on Dairy Cattle Breeding is hosting a half-day meeting on the genetics of feed efficiency. Dr. Peñagaricano will be one of five featured speakers for the program.
Keynote presentations are:
- S. efforts to create a feed efficiency database – Mike Vandehaar, Michigan State
- How do we measure freed efficiency? – Heather White, UW Madision
- Precision dairy is here to stay – James Koltes, Iowa State
- Genetic dissection of dairy cow feed efficiency – Francisco Penagaricano, Univ. of Florida
- Preview of feed efficiency genetic evaluations – Paul VanRaden, USDA AGIL
- Panel discussion feed efficiency and social responsibility
Doors open at 8 a.m. for coffee, pastries and fellowship and the program will start promptly at 8:30 a.m. The meeting will be held in Mendota #4 in the Exhibition Hall at the Alliant Energy Center. There is no admission charge but to assure adequate seating pre-registration is invited here. But walk-ins will be welcome. https://www.eventbrite.com/e/2019-cdcb-industry-meeting-tickets-69285192877