Friday, December 19, 2014

GE-EPDs and Genetic Selection
Breed Improvement Session
Angus Means Business National Convention

There was standing room only for the Breed Improvement Session of the Angus Means Business National Convention on November 4th, 2014.

Genomic Recalibration
Dan Moser, Angus Genetics Incorporated
Performance data reported to the American Angus Association has become more important than ever. Not only is this data necessary to get highly precise estimates from sires, but it is the foundation of developing genomic predictions for genomic-enhanced EPDs. In the training or recalibration of genomic predictions, basically an EPD effect is estimated for every DNA variant included in the genomic prediction test. The genomic prediction (also called the Molecular Breeding Value, MBV) is the sum of every EPD effect for approximately 50,000 DNA variants evenly spread throughout the cattle chromosomes.

Initial GE-EPDs in 2010 were based on 2,253 animals. In 2012 the training set increased to  11,756, by 2013 the training set was larger than 38,000 animals, and now in 2014 has reached over 57,000 animals.

Moser said, "No one item by itself gives us the best story." Precision of genetic predictions relies on using pedigree, performance, progeny, and MBV.

Tonya Amen, Angus Genetics Incorporated
MaternalPlus is a voluntary, inventory-based reporting system. This whole-herd reporting program allows the capture of reproductive trait data. This allows improvement of reproductive selection tools.

"If it is important to them, it needs to be important to you," Amen stated to encourage seedstock producers to keep the needs of their commercial customers in mind. While decreasing generation interval is important in a seedstock setting, longevity is vital in commercial operations. For each inventoried female, producers need to report a calf record, disposal code for the cow, or reason the cow did not have a calf reported.

Certain results will only be available to MaternalPlus members. This include:

  • Within herd genetic trend- how do you relate to the breed? 
  • Production records 
  • Calving distribution 
  • Cow-age performance summary 
  • Dam disposal report- why are your cows leaving the herd? 
  • Female age distribution 

New perks coming to the program include:

  • A MaternalPlus logo, 
  • MaternalPlus catalog inserts
  • Other customizable MaternalPlus advertisements 
  • Periodic mention as MaternalPlus participant in the Angus Journal and Angus Beef Bulletin 

Dan Moser pointed out that AAA has been ahead in many instances, but in terms of cow herd reporting and longevity EPDs the Angus Association has been way behind.

Angus $Value Indexes
Dan Moser, AGI
The $F index (SHORT EXPLANATION) originally include rough estimations of feed efficiency as fewer days on feed due to quicker growth rate. But, the relationship between feed efficiency and growth is not 1 to 1. Intake data has accumulated over time and now allows inclusion of feed intake into $F and $B indexes. Feed intake remained fairly level for the early years of $F indexes, but in the past few years, genetic trend for feed intake has changed drastically. Each year the economic assumptions of the $Value indexes are updated, and AGI is taking this opportunity to incorporate feed intake into the $F and $B indexes. The changes in index values will be mostly be due to updated economic assumptions with changes due to feed intake being secondary.

Foot Scores
Moser also discussed foot scoring. Producers are reporting two main issues: shallow heals with long toes and scissor or corkscrew claws, which may be related. What we need is a simple system to score cattle for these two conditions. In a new research program members will provide two scores to AGI, foot angle and claw set. Both scores are on a 1 to 9 scale where 5 is ideal. The AGI scoring system will be similar to parts of the Australian system, but greatly simplified. Breeders are asked to score the worst foot. An ideal angle would be a 45 degree angle between hoof and pastern. EPDs may be calculated in the future, but the soonest impact may be more attention paid to foot structure. Australian data suggests heritabilities around 15% for foot angle and hoof set. Scoring must be done prior to hoof trimming. Producers will need to submit basic information on feed ration when submitting foot scores. EPDs will be provided as soon as sufficient data is available.

See the 2014 Angus Convention Newsroom for more information from the session.


Wednesday, December 17, 2014

Feed Intake, $F, $B and You

In October, we reported that Angus Genetics Inc would be including feed intake data into $F and $B indexes. On December 5th, 2014 those changes took effect. In our October poll, 91% of the respondents indicated that they considered including feed intake data as an improvement to the $B index. And, the data backs this up (see here for more about our data-driven philosophy). Since 2004 the American Angus Association has seen an increasing genetic trend for feed intake. This means Angus producers have been indirectly selecting for increased feed intake, which is a negative when we are striving for more efficient cattle.

Figure 1. Deregressed estimated breeding values for birth and weaning weight plotted against birth date. Deregressed estimated breeding values plotted against birth date for 3,570 Angus animals. The blue lines represent fitted linear and red lines represent fitted quadratic regressions. a. Deregressed birth weight EBV, and b. Deregressed weaning weight EBV.
Decker et al. BMC Genomics 2012 13:606 doi:10.1186/1471-2164-13-606
One of the best examples of moderating one trait while improving others is the relationship between birth weight and other production traits. Since the mid-1980s Angus producers have been decreasing birth weight and the associated calving problems while increasing correlated traits such as weaning weight and carcass weight. This is perhaps one of the great accomplishments of modern animal breeding—the ability to break apart negative relationships between traits. Including feed intake into $B will allow Angus breeders to break the negative relationship between production and feed intake.

The USDA funded Beef Feed Efficiency Project has provided many of the phenotypes used in the Angus feed intake EPD calculation. The Beef Feed Efficiency Project will continue to work with breed associations and producers to provide tools and resources for the improvement of feed efficiency.

For more information on changes to $B and $F see this FAQ sheet by the Angus Association.