D. H. “Denny” Crews, Jr. Colorado State University BIF SubCommittee Chair

 Guidelines draft and editing ◦ Dr. G. E. Carstens, Texas A&M University ◦ Dr. R. A. Hill, University of Idaho ◦ Dr. J. A. Basarab, Alberta Agriculture and Food  Academic reviewers and discussions ◦ Dr. D. Strohbehn, Iowa State University ◦ Dr. R. M. Enns, Colorado State University ◦ Dr. M. Nielsen, University of Nebraska  Industry representatives ◦ Dr. S. Northcutt, American Angus Association ◦ Dr. L. Hyde, North American Limousin Foundation ◦ Dr. R. Williams, American International Charolais Association

 General minimum guidelines ◦ Individual feed intake data recording ◦ Reporting of intake and efficiency data  Animal classes ◦ Growing bulls ◦ Steer and heifer progeny  Guidelines document ◦ Posting to the web ◦ Incorporation into BIF guidelines, 9 th edition  Guidelines updates

 Breed  3-generation pedigree  Age of dam  Birth date  Birth weight  Weaning date  Weaning weight  Information required for defining feeding contemporary group ◦ Reference to breed association rules

 Start of test date ◦ Back-calculate age on test using birth date ◦ This is pre-warmup start date  Age limits should be defined ◦ Weaning is approximately 205 d, with range 175 to 235 d ◦ Minimum age on test should be older than weaning  Animals within a feeding contemporary group ◦ Maximum age range d  Pen of feeding will also define CG for intake traits ◦ Dependent on weaning CG size ◦ Target > 5 animals per feeding CG

 Adjustment period is typically 21 days ◦ Acclimation to facility and equipment ◦ Diet warmup – transition to final test diet  End of transitional period / start of test will be recorded ◦ Used to define start of intake recording  Longer warmup periods are okay, but probably unnecessary ◦ This will likely be a decision by test managers  Transitional diets for market progeny ◦ Step-up from growing to finishing ration is common ◦ The transition period data can’t generally be used ◦ The goal is to get intake on a constant diet ◦ Research is unclear regarding grow/finish choice with progeny tests but finishing diet is most common

 Minimum 70 d after warmup is required ◦ This makes a 91-d minimum total test period ◦ Intake requires less time, but growth requires about 70 d ◦ Animals don’t specifically have to have intake records for all (growth) test days if intake recording equipment usage is an issue  Ad libitum intake is required  Sickness ◦ Days/dates absent from the pen are usually recorded for all animals ◦ Full consumption (ad libitum) should return before recording resumes  Removal of animal(s) from pens ◦ Absence leads to a “non-test-day” and data is set to missing ◦ Working days (weights, RTU) are removed ◦ Equipment failures are also “non-test-day” criteria

 No assumptions or restrictions about diet ingredients ◦ These are specific to test location and conditions ◦ Ingredient composition should be recorded  Proximate analysis is also recommended  All animals within a test receive the same diet  Energy density should be sufficient for expression of animal differences  Dry matter content of the diet must be tested ◦ Intake is expressed on a dry-matter basis ◦ Increases comparability with other tests/studies ◦ Minimize measurement variation

 Dry matter intake per day is the key measure  Electronic equipment ◦ Follow hardware specifications for animal density  GrowSafe: ~7 (8 ?) young bulls or ~9 steer/heifer progeny per node  Calan: 1 animal per gate  Beginning/end of data recording period ◦ Avoid animals with large missing blocks  Minimum days with intake data ◦ Most studies show days or more is sufficient ◦ Some missing data is to be expected, especially with some hardware ◦ Data auditing will remove some data from test days

 Recommend > 6 live weights during the test period ◦ Enables the regression of live weight on test day to get ADG ◦ Minimization of measurement error ◦ R 2 should be at least 0.90 for these animal regressions, else ADG missing  2 on / 2 off is less desirable ◦ Easier to collect, but data quality is lower  Serial weights ◦ 14-d intervals are common, but not required ◦ Some test utilize 21- or 28-d weight intervals ◦ Equal spacing seems to be important

 Measuring body composition is important ◦ Intake is related to fat / muscle deposition = energy sink ◦ Ultrasound measures of FAT and REA are desirable ◦ Start/end is desirable ◦ If only one ultrasound measure is taken, measure at end of test  Utilize BIF guidelines for ultrasound data collection  Consult and follow breed association specific rules ◦ Data could also support carcass evaluation  Serial ultrasound ◦ Can estimate deposition “curves” for body composition similar to ADG ◦ Multiple measurements on a commercial test will be more expensive

 End of test date ◦ Computation of ages and length of test ◦ Test should be completed by 450 d of age  Ensure intake data recording equipment is known  Intake data “audit” ◦ Increases test data integrity ◦ Allows for across-test comparisons ◦ Audits for outliers and potentially biased data  Intake and growth correlations  Within animal variability  Residual feed intake calculations  Equipment failures  Extent is somewhat equipment specific