Pasture-Based Nutritional Considerations for Beef Cattle Lawton Stewart Grazing School May 6, 2010

Developing a Feeding Strategy 1.Understand your production system – Fall Calving – Spring Calving – Continuous 2.Understand your forage system – Pasture – Conserved forage 3.Develop an economical supplement

Basic Nutrients Six Key Nutrients – Water – Protein – Carbohydrates – Fats – Minerals – Vitamins

Crude Protein -Proteins are the building block for animals and are chains of amino acids -Crude protein is determined by the amount of Nitrogen (N) in a feed multiplied by Nitrogen is used to determine the amount of protein, because of the N is critical part of the amino acid structure and makes up approximately 16% of the protein structure. -Protein Fractions: Degradable Intake Protein (DIP) Undegradable Intake Protein (UIP)

Energy Energy is defined as the capacity to do work. Common measurements of energy in ration formulation – Net Energy (NE) – Broken into maintenance, growth, lactation, etc. – Total Digestible Nutrients (TDN) – A method that calculates energy based all sources of energy. Requirements change based on age, sex, stage of production, work.

Energy Sources: Starch, fats, proteins and cellulose – Majority of energy in beef cattle rations is the cellulose in forage.

Nutrient Requirements The amount of nutrient that an animal needs to perform a specific purpose. Determined by: weight, sex, age, growth rate, stage of production.

Reproductive Efficiency The most important factor affecting profitability Highly dependent on proper nutrition

Nutrient Priorities 1.Maintenance 2. Growth (Heifers) 3. Lactation 4. Reproduction

Brood Cow Nutrient Requirements

Separate Cows Based on Stage of Production Over feeding = FAT COWS Underfeeding = LOSE CONDITION

Body Condition Scoring??? 1-9 – Assess the energy reserve status of a cow. BCS-1BCS-9

Body Condition Scoring??? 4 5 Kunkle et al., 1998

When to BCS?

Nutrients needed to increase BCS over a 70 day period* Mature BW, lb BCS Addition TDN needed above normal requirements * Nutrients need to move up to the given BCS

What does that mean??? A 1200 lb cow at weaning is a BCS 4 How much more TDN does she need to get to a BCS 5 in 70 days? What would here total TDN requirement be? What would the requirement be post calving?

What about her? A 1200 lb cow at weaning is a BCS 6 Can we utilize her energy reserve if forage is limited? Mobilized fat is worth 80% of dietary calories. – To get to BCS 6 takes an additional 10.4% TDN. – To go down from BCS 6 is (10.4 * 80% = 8.3% TDN) A diet of 40%TDN (48% requirement for dry cows – 8.3% = ~40%) will carry her 70d keep her above a BCS 5. YES

Nutritional Requirements of Weaned Calves Medium-frame steer calves Wt (lb) Daily Gain (lb) Crude Protein (%) TDN (%) Know the requirements to keep calves gaining Remember: – Gain and health = $$$$ – Health is a function of immunity and nutrition

Suitable for: Forage CP (%) TDN (%) Peak Lactation Late Lactation Dry Cow 600 lb calf gain, lb/d Poor Hay 748No Yes0.5 Average Hay 1055NoYes 1.25 Good Hay 1260Yes 1.35 Bermudagrass Pasture 1364Yes 1.60 Tall Fescue Pasture 1462Yes 1.50 Winter Annuals –Vegetative 1672Yes 2.5 Winter Annuals –Mature 1258No 1.3 Potential Forages

Available Forages Grazed Forage? Corn Silage Drought stressed crops Hay produced – High quality??? – Low quality??? Hay produced – Storage – Testing – Inventory L. Stewart, UGA Extension TEST FORAGES!!!! Hay Cutting Production Phase 1.CP 14%Dry Cow TDN 60% 2.CP 10%Late Gestation TDN 55% 3.CP 6%Early Lactation TDN 47%

Supplementation Strategies 1.Winter Annuals 2.Commercial Feeds 3.Liquid Feeds/Tubs 4.Byproducts

Winter annuals Warm-season perennial grasses Winter annuals (small grain/annual ryegrass

Lick Tanks, Tubs, and Blocks Advantage: 1.Convenient 2.Reduced Labor 3.Additional minerals and vitamins Disadvantage??? 1.Intake? 2.Adequate nutrients? 3.Affordable?

Do they work miracles? “They’ll eat the old hay from last year if I use liquid feed”

Using a Lick Tub for CP PoorHay 7% CP, 46%TDN Fair Hay 10% CP, 50%TDN

Using a Lick Tub for Energy Poor Hay 7% CP, 46%TDN Fair Hay 10% CP, 50%TDN

RUMEN Microbial Crude Protein Production Nitrogen “Mortar” Energy “Bricks” Crude Protein Energy SMALL INTESTINE

Byproduct Feeding What's available Price – Evaluate on DM basis – Look at $/nutrient Handling / Storage Minerals

Potential Byproducts 1.Grain Corn gluten feed Distiller’s grains Soy Hulls Wheat middlings 2.Cotton Whole seed Gin trash Hulls 3.Sugar and starch production Cane, beet & corn molasses Salvage candy 4.Vegetable Cull vegetables

SMALL INTESTINE RUMEN Sources of Energy FiberStarch

Effect of Increasing Corn on Hay Intake and Digestibility Corn, lbs/day None Hay DMI lbs DOMI, lbs Hay OM Digest, % Oklahoma State, 1987 JAS 65:557

Effect of Increasing Soybean Hulls on Hay Intake SH, lbs/day None Hay, OMI, lbs DOMI, lbs OM Digestibility, % Oklahoma State, 1990 JAS 68:4319

Byproduct Feeding What's available Price – Evaluate on DM basis – Look at $/nutrient Handling / Storage Minerals

Nutrition Tools UGA Basic Balancer UGA Feed Cost Analyzer Commodity Feed Source List Plus Many More Ugabeef.com

Take Home Message Understand changing nutrient needs throughout production cycle. Know your forages. Use economic strategies when supplementation is needed.

For up to date information on: Beef cattle outlooks Marketing Production information

Thank You! Questions?