Feed Saved (FSAV)

Feed Saved was the first CDCB trait that directly evaluates feed efficiency. Genetic and genomic evaluations are published for Holstein males and females.

Benefits of Trait

Feed costs can make up over half of the total costs on a dairy farm, per USDA ERS, 2018. Selecting for more feed-efficient cows can reduce these costs and improve profitability.

Feed Saved Trait

The FSAV predicted transmitting ability (PTA) represents the expected pounds of feed saved per lactation based on evaluations for Body Weight Composite (BWC) and Residual Feed Intake (RFI). Evaluations are expressed in pounds of feed saved per lactation above or below the breed average. Larger, positive values are more favorable.

Residual Feed Intake (RFI) is the difference between an animal’s actual feed intake and its expected feed intake based on its size and growth compared to the breed average base.

Introduced December 1, 2020 for Holstein males and females.

Unit of Measurement: Pounds of dry matter intake

For example, daughters of a Holstein bull with a FSAV PTA of +200 pounds per lactation are expected to consume an average of 200 pounds of feed less than expected based on production and body size. Daughters of a Holstein bull with a FSAV PTA of -300 pounds per lactation are expected to consume an average of 300 pounds of feed per lactation more than expected based on production and body size.

Feed Saved is not incorporated in Net Merit $ or other CDCB indices so as not to “double count” Body Weight Composite. Instead, Residual Feed Intake in the trait included in NM$ and other indices as of August 2021 for Holstein Animals.

Correlations between Residual Feed Intake (RFI) with yield traits are effectively zero by definition. Small correlations (<10%) have been observed with traits such as Daughter Pregnancy Rate, Productive Life, and the disease resistance traits.

Estimated heritability is 19% for Residual Feed Intake (RFI), an increase in December 2021 due to additional data and herd variance adjustments. Estimated heritability for body weight composite is 40%.

Young genomic bulls are expected to have reliabilities averaging 28% for Feed Saved, and progeny tested bulls are expected to have genomic reliabilities averaging 38%. As additional data are accumulated, reliabilities will increase.

CDCB FSAV evaluations were developed using data collected through research funded through grants in 2010 by National Institute for Food and Agriculture and in 2019 by Foundation for Food and Agriculture Research and CDCB. Research herds currently involved are Michigan State University, University of Wisconsin-Madison, Iowa State University, University of Florida, and the Animal Genomics and Improvement Laboratory, ARS, USDA. Collection of additional genotypic and phenotypic records continues at the five U.S. research herds and added to the CDCB database as available. Since the trait was introduced, feed intake records from Canadian research herds were added to the reference population.

Future Development

Research around feed efficiency is very active in the U.S. and globally. Phenotypic and genotypic data is being continually collected and added to the CDCB database. International collaborations will allow more data to be incorporated. By combining available data, feed efficiency evaluations will become more accurate and larger research studies can be conducted. The U.S. research team is part of the Resilient Dairy Genome Project, a large international effort led by several Canadian institutions. Participants share data for traits related to feed efficiency to expand the available reference population. This is especially important for a trait like feed efficiency in which phenotypes are very expensive and labor-intensive to collect, thus resulting in a very small population of animals with phenotypes. We are actively evaluating the data from outside North America to ensure compatibility with our current feed efficiency database.

Related Publications
Genetic relationships between different measures of feed efficiency and the implications for dairy cattle selection indexes. Tempelman et al, 2020

Net Merit as a measure of lifetime profit: 2021 revision. VanRaden et al, 2021

Heterogeneity in genetic and nongenetic variation and energy sink relationships for residual feed intake across research stations and countries. Tempelman et al, 2015

Harnessing the genetics of the modern dairy cow to continue improvements in feed efficiency. VandeHaar et al, 2016

Genomic prediction of residual feed intake in US Holstein dairy cattle. Li et al, 2020