D. H. “Denny” Crews, Jr. Colorado State UniversityBIF 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, 9th 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 90-100 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 45-50 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◦ R2 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

Denny.Crews@ColoState.eduG-Carstens@tamu.eduRodHill@UIdaho.eduJohn.Basarab@gov.ab.ca