Improvement of Beef Cow Biological Efficiency Dan Shike, PhD University of Illinois Champaign-Urbana

Why all the buzz about efficiency? Increasing world population Increased utilization of feed for fuel Increasing feed cost (including forages) Other inputs increasing in cost Fuel, transportation, fertilizer 2

Profitability Traditional focus on outputs Feed costs have historically been 50-70% of the cost of production in beef enterprises As corn prices approached and exceeded $7 per bushel, feed costs were nearly 80% of the costs in many feedlot operations in US

Feed Efficiency Feed:Gain < 2:1 < 3.5:1 > 6:1 4

Why are beef cattle less efficient? Maintenance requirements 50% of total energy expended in beef production is used for maintenance of the cow High fiber diet Rumen fermentation Bacteria produce VFA Bacteria produce methane 5

Why haven’t we made any progress? No selection for feed efficiency Why? Requires individual feeding Expensive facilities High labor requirement Lack of social interaction decreases feed intake Difficulty in defining efficient female 6

Measures of feed efficiency Feed conversion ratio (FCR) Residual feed intake (RFI) Residual BW gain (RG)

Measures of efficiency Residual Feed Intake (RFI) The difference between actual intake and predicted intake based on animal’s gain, maintenance requirements for its body weight, and composition NEGATIVE RFI IS GOOD! Required less feed then predicted Independent of growth and mature size Linked to biologically relevant traits associated with feed efficiency Digestibility, heat production, protein turnover

Measures of efficiency Residual BW Gain (RG) The difference between actual gain and predicted gain based on animals intake, maintenance requirements for its body weight, and composition POSITIVE RG IS GOOD! Gained more weight than predicted Correlated to growth

Beef cow efficiency What about cow efficiency? ~70% of feed resources for cowherd ~70% of feed for maintenance 50% OF ALL FEED TO MAINTAIN COWHERD How do we define cow efficiency? Pounds of calf weaned per cow exposed Pounds of calf weaned per cow exposed per unit of feed energy consumed What about longevity?

Efficient Cow Can you tell by looking at them?

Maintenance energy High Maintenance Cow Low Maintenance Cow High milk production High visceral organ weight High body lean mass Low body fat mass High output and high input Low milk production Low visceral organ weight Low body lean mass High body fat mass Low output and low input

Environment Restricted feed resources Abundant feed resources Favors more moderate size, moderate milk production “Low maintenance” breeds are most efficient Angus, Red Poll High maintenance breeds are least efficient Simmental, Charolais, Limousin, Gelbvieh Favors larger, heavier milking biological types “High maintenance” breeds are most efficient Simmental, Charolais, Limousin, Gelbvieh Low maintenance breeds are least efficient Hereford, Angus, Red Poll Jenkins and Ferrell, 1994

Cow efficiency research Funded by American Angus Association Post-weaning intake evaluation on replacements All females given opportunity to breed Evaluate 2-year-old cows 60 d postpartum evaluation period 2 week intake evaluation BW, body condition score, ultrasound fat, milk production 240 d postpartum evaluation BW, body condition score, ultrasound fat Repeat again as 5-year-old mature cows

Variation in cow efficiency Small Cow Big Cow Moderate Cow BW, lbs 1186 1453 1305 1307 Milk Production, lbs 15.9 22.9 17.9 20.5 BCS 5.5 6.0 DMI, lbs 56.7 45.4 54.5 35.7 Adcock et al., 2011

Correlations of heifer and 2 year-old cow traits CowL DMI CowL BW CowL Milk CowDry DMI CowDry BW Heifer DMI 0.45 -0.21 -0.17 0.42 0.09 Heifer RFI 0.20 -0.01 -0.04 0.15 0.02 Heifer RG -0.11 0.12 -0.05 0.14 CowL = Cow traits at 60 d postpartum (lactating) CowDry = Cow traits at 240 d postpartum (dry cow) Correlations in bold are significant at P ≤ 0.05

Ongoing project Intake on 486 heifers postweaning Intake on 274 2-year-old cows Intake on 34 5-year old cows 2nd year of 5-year-old cows this year Continue to evaluate fertility, productivity, and longevity

National Program for the Genetic Improvement of Feed Efficiency in Beef Cattle

Intake x Diet Is there a genetics x diet interaction for intake or RFI? Feedlot efficiency trials – high-energy, grain-based Cowherd – moderate to low-energy, forage-based Why would they be the same? Maintenance energy (heat production, protein turnover) Why might they be different? Intake regulation Grain – chemostatic Forage – fill-regulated

Forage vs. Grain 162 spring-born, Charolais-sired calves 274 fall-born, Charolais-sired calves Period 1 (half on forage; half on grain) 3 week transition / adaptation period 2 day initial and final weights (70 d test) Ultrasound 12th rib fat thickness at start and finish Weighed every 2 weeks Period 2 evaluation (all cattle on grain) 3 week transition/adaptation period Ultrasound 12th rib fat thickness

Diets Forage Grain Ingredient % of diet, DMB Husklage 47.5 Alfalfa haylage Supplement 5 NEm = 1.557 Mcal/kg NEg = 0.956 Mcal/kg Ingredient % of diet, DMB High moisture corn 20 Ground corn 30 Husklage 25 DDGS 15 Supplement 10 NEm = 2.004 Mcal/kg NEg = 1.359 Mcal/kg Target 2 lbs/d gain Target 4 lbs/d gain

Forage – Grain (spring-born) Item Forage DMI Forage ADG Forage RFI Grain DMI Grain ADG Grain RFI DMI 1 0.69 0.58 0.57 -0.09 0.26 0.00 0.51 0.01 0.13 0.21 -0.06 0.41 0.53 Correlations in bold are significant at P ≤ 0.05

Forage – Grain (fall-born) Item Forage DMI Forage ADG Forage RFI Grain DMI Grain ADG Grain RFI DMI 1 0.70 0.51 0.62 -0.29 0.15 0.00 0.40 -0.22 -0.04 0.28 0.01 0.35 0.18 0.66 Correlations in bold are significant at P ≤ 0.05

Summary Variation in feed intake and efficiency Opportunity to select for and improve Best measure / definition of efficiency? Depends if it is feedlot or cowherd Depends if it is for selection or research Need to continue to collect phenotypes Need INTAKE Understand relationships of traits Geneticists will determine best tools for selection

Questions?