Problems with telephone hookup? Contact the operator at the University of Illinois Contact the operator at the University of Illinois Then hit 0 for the operator Then hit 0 for the operator Mute your phone by hitting #5, if you don’t we will! Problems with Telebridge System? Hit #0 Hit #0 Welcome to Session 5

“The Interaction of Crossbred Genetics with Environments” Welcome to Session 5

Your host Dr. Bob Weaber Beef Cattle Extension Specialist, University of Missouri

Session 5 “The Interaction of Crossbred Genetics with Environments”

Dr. Don Kress Professor Emeritus Montana State University Today’s presenters Dr. Don Franke Professor Emeritus Louisiana State University

THE INTERACTION OF CROSSBRED GENETICS WITH ENVIRONMENTS Don Kress Montana State University Don Franke Louisiana State University

OVERVIEW I. Introduction II. Basics A. Definition of G x E or GEI B. Due to magnitude or change in rank III. Research Results A. Bos taurus B. Bos indicus IV. Summary

DEFINITION G x E or GEI occurs when differences among G’s change from one E to another E.

G x E DUE TO CHANGE IN MAGNITUDE

G x E DUE TO CHANGE IN RANK

PRODUCTIVITY OF DIFFERENT BIOLOGICAL TYPES OF COWS AT HAVRE, MONTANA

COW WEIGHT AND PRODUCTIVITY IN EASTERN MONTANA AT LARRL MacNeil et al. (1992)

PRODUCTIVITY OF TWO BIOLOGICAL TYPES OF COWS AT TWO LOCATIONS IN MONTANA

PRODUCTIVITY OF FOUR BIOLOGICAL TYPES OF COWS UNDER THREE LEVELS OF NUTRITION IN AUSTRALIA Hearnshaw and Barlow (1982)

PRODUCTIVITY OF COW BIOLOGICAL TYPES IN CANADA Fredeen et al. (1987)

PRODUCTIVITY OF TEN BIOLOGICAL TYPES OF COWS IN TWO NEW ZEALAND LOCATIONS Baker and Carter (1982)

PREDICTED BIOLOGICAL EFFICIENCY (GRAMS OF CALF WEANED·KILOGRAM DRY MATTER INTAKE -1 ·COW EXPOSED -1 ) AT VARYING DRY MATTER INTAKES FOR NINE BREEDS OF CATTLE Jenkins et al. (1994)

SUMMARY I.Important GxE interactions are those due to change in rank. II.There are important GxE interactions for Bos taurus crossbred cow productivity. III.Most of these important interactions involve reproductive traits. IV.It is important to match the genetic potential of Bos taurus crossbred cows to the environment.

A large majority of cattle operations in the Southern Region are commercial cow-calf herds. Many operations utilize Brahman crosses of one form or another. My objective is to review breed type x environmental interactions involving Brahman cross cows.

Pregnancy rate in FL and NE Olson et al. (1991)

Weaning weight in FL and NE Olson et al. (1991)

Heifer pregnancy rate in OK when exposed to calve in Spring and Fall Bolton et al. (1987)

Age at first calf for Spring and Fall calving in OK McCarter et al. (1991)

Lifetime calving percent for Spring and Fall calving McCarter et al. (1991)

Calving rate of crossbred heifers exposed to calve at 24, 30, or 36 mo in LA DeRouen et al. (1989)

Weaning rate of Brahman, Shorthorn, and B – S crossbreds on three pasture programs in FL Peacock et al. (1971)

Production per cow on three pasture programs in FL Koger et al. (1975)

Calf weaning weight on bermuda and tall fescue pastures in AR Brown et al. (1993)

Calving percent on bermuda, fescue, and combination pastures in AR Brown et al. (2000)

Weaning weight per cow exposed on bermuda, fescue and combination pastures in AR Brown et al. (2000)

Summary Important GEI exist with Brahman cross cows Important GEI exist with Brahman cross cows Fall calving reproductive rates were lower and decreased with increasing Brahman inheritance Fall calving reproductive rates were lower and decreased with increasing Brahman inheritance

Summary, cont. Brahman crossbred cows seem to be more tolerant to differences in quality of pasture programs than Bos taurus cows Brahman crossbred cows seem to be more tolerant to differences in quality of pasture programs than Bos taurus cows Cow breed types should be matched with the environmental conditions and resources that are available Cow breed types should be matched with the environmental conditions and resources that are available

Session 6 on November 8th Dr. Darrh Bullock, University of Kentucky “Is there Gold in Them Thar Crossbreeding Hills?”