Improvement of Beef Cow Biological Efficiency

Dan Shike, PhDUniversity of IllinoisChampaign-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

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 EfficiencyFeed:Gain

< 2:1 < 3.5:1 > 6:1

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

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

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• High milk production • High visceral organ weight • High body lean mass • Low body fat mass • High output and high input

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

EnvironmentRestricted 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

Abundant feed resources• 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– 2 week intake 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

Moderate Cow

BW, lbs 1186 1453 1305 1307Milk Production, lbs 15.9 22.9 17.9 20.5BCS 5.5 6.0 6.0 5.5DMI, 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

HeiferDMI 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 -0.05 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-

basedCowherd – 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 period2 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 period2 day initial and final weights (70 d test)

Ultrasound 12th rib fat thickness Weighed every 2 weeks

DietsForage

Ingredient % of diet, DMB

Husklage 47.5Alfalfa haylage

47.5

Supplement 5

NEm = 1.557 Mcal/kg NEg = 0.956 Mcal/kg

GrainIngredient % of diet,

DMBHigh moisture corn

20

Ground corn 30Husklage 25DDGS 15Supplement 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)

ItemForage

DMIForageADG

Forage RFI

Grain DMI

Grain ADG

Grain RFI

Forage

DMI1 0.69 0.58 0.57 -0.09 0.26

Forage

ADG1 0.00 0.51 0.01 0.13

Forage

RFI1 0.21 -0.06 0.41

Grain DMI 1 0.53 0.58

Grain ADG 1 0.00

Grain RFI 1Correlations in bold are significant at P ≤ 0.05

Forage – Grain (fall-born)Item

Forage DMI

ForageADG

Forage RFI

Grain DMI

Grain ADG

Grain RFI

Forage

DMI1 0.70 0.51 0.62 -0.29 0.15

Forage

ADG1 0.00 0.40 -0.22 -0.04

Forage

RFI1 0.28 0.01 0.35

Grain DMI 1 0.18 0.66

Grain ADG 1 0.00

Grain RFI 1Correlations 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?