Grazing Management to Meet Animal Performance Targets Mark Kennedy State Grazinglands Specialist USDA-NRCS Houston, MO Meeting the Nutritional Needs of Livestock from Pasture INTAKE INTAKE INTAKE Overview Balancing animal numbers and forage supply Matching diet quantity and quality needs Matching grazing management and paddock numbers Animal Intake / Stocking Rate There is only a certain amount of forage produced in any plant community that is available for use. Every acre can only support a finite amount of animal weight Matching the type and number of livestock to the forage base is very important for meeting animal targets as well as maintaining pasture condition The 1st Step: Balance Livestock Numbers with Forage Supply • Stocking rate: The number of animals or animal liveweight assigned to a grazing unit on a seasonal basis. • Carrying capacity: The stocking rate that provides a target level of performance while maintaining the integrity of the resource base. • Stocking rate has a big effect on intake and availability. Carrying capacity of pasture is determined by four factors Carrying Capacity Forage Production X Seasonal Utilization Rate X Length of the Grazing Season = Daily Intake Carrying Capacity Example: Stocker operation(buying 500# selling 800#) 200 day seasonal grazing (April 1 - Oct. 20) 16 paddock system (1-3 day grazing period) 8000 lb. total forage production (from history/experience, soil survey, forage suitability groups) Grazier’s Arithmetic Then …. Carrying 8000 lb/acre X .65 = Capacity .03 lb forage/lb liveweight X 200 days = 867 lb liveweight / acre Grazier’s Arithmetic 867 lbs. per acre/500 lb = 1.73 steers/ac Can we stock 1.73 steers/ac initially? If we expect them to grow to 800 lb. then 800 + 500 = 1300/2 = 650 (avg wt) 867/650 = 1.33 steers/ac Forage Intake on Pasture Quantity/Availability Proper stocking rates, grazing management Quality Grazing management, species selection Effect of Forage Availability on Relative Forage Intake Effect of Forage Availability on Relative Forage Intake How much does a 1,000 lb Cow eat? @2.5% BW about 25lb DM With limited availability 19 lb DM Intake 75% Availability Time spent grazing 6–10 hours per day 6–10 hours ruminating Biting rate Cattle avg. 50 bites/min Bite size Cattle average 0.3 g DM per bite Measured range of 0.07 to 0.59 g per bite Related to availability 25% forage quality Factors Affecting Intake Dry matter intake = Biting Rate x Biting (grazing) Time x Bite Size Dry matter intake = 50 bites/min x 600 min/day x 0.3 g/bite = 9.0 kg or 19.8 lb DM intake per day Factors Affecting Intake If bite size is only 0.07 g/bite 50 bites/min x 600 min/day x 0.07 g/bite = 2.1 kg or 4.6 lb DM intake per day If bite size is 0.59 g/bite 50 bites/min x 600 min/day x 0.59 g/bite = 17.7 kg or 38.9 lb DM intake per day Effect of Forage Availability on Relative Forage Intake 6 - 10” 2 - 3” The Quantity – Quality Compromise Factors affecting forage quality Plant maturity Species Plant Part Factors affecting forage quality Plant maturity Growth stage Length of rest period Plant Growth Phases Rest Period Needs Clover Annual Lespedeza Orchardgrass Stockpile Birdsfoot Trefoil 30 - 35 days 20 - 25 days Yield (tons/A) 1.0 Fescue 15 - 20 days 1.5 0.5 0.0 Spring Summer Fall Factors affecting forage quality Plant maturity Species Factors affecting forage quality Species Legumes > grasses Annuals > perennials Cool-season > warm season Forage Chain Winter J F Spring M A M Summer J J A Fall S O N Winter D LEGUME, Cool seanon grass – based perennial pastures Winter Annuals-rye, ryegrass, triticale, brassicas High Quality Hay/stockpiled fescue Summer Annualsforage sorghums, sudangrass, millet, corn, crabgrass, perennial warm season grasses Winter Annuals – rye, ryegrass, triticale,brassicas High Quality Hay/stockpiled fescue Diversity is the Key Diverse pastures are more productive Are less prone to disease and insect damage Broadens nutritional opportunities of the grazing livestock Legumes provide nitrogen for the grass and improve overall diet quality Factors affecting forage quality Plant part Leaves vs stems First bite vs second bite 3 Factors Affecting Forage Quality 1. Maturity 2. Species 3. Plant Part 1st bite: leaves with low fiber High quality 2nd bite: medium quality 3rd bite: stems with high fiber – low quality – leave for regrowth Animal Requirements vs Forage Quality at Different Maturities • Can use different stages of quality to our advantage • Adjust body condition score • Increase, maintain, or decrease body condition • Creep grazing • Calves allowed to creep gaze into higher quality pasture • “Leader – Follower” grazing • Animals with highest nutrient needs graze pasture first followed by those with lower nutritional needs High Quality -First grazers Medium quality - Last grazers Expected Intake of Different Quality Forages Intake as a Forage Relative Feed % of Body Quality Value Weight ---------------- ---------------- ---------------Poor <80 1% Average 85-115 2% Good 120-140 2.5% Excellent >150 >3% Estimated Nutrient Content of Tall Fescue at Different Maturities NDF % ADF % CP % NEm NEg Mcal/lb Mcal/lb Vegetative 49 27 20 0.70 0.39 Late boot 57 36 16 0.58 0.29 Mature 70 42 8 0.53 0.23 Animal Requirements vs Forage Quality at Different Maturities 600 lb beef steer, 2.0 lb ADG Intake Intake % bw lb DM Requirement CP lb NEm Mcal ADG lb/day 2.5 15.0 1.6 5.2 Vegetative 2.5 15.0 3.0 10.5 2.0+ Late boot 2.1 12.6 2.0 7.2 1.2 Mature 1.7 10.2 0.8 5.4 <0.5 Performance Monitor your forage for quality Tried and true method How high is the pile? Forage Quality: Pancake batter, Pumpkin Pies or Wedding Cakes? The Key to Successful Grazing Management Flexibility The ability to adapt or modify, being responsive to changing conditions Grazing Management Objectives Have grazing animals take 1 large bite or mouthful (animal intake) off of as many plants as possible in a pasture (Utilization) Remove the animals from the pasture before any regrowth occurs and by the time 50% of the current growth has been removed (plant persistence/health)(animal intake) Have enough pastures to allow sufficient regrowth and rest before being grazed again (rest/plant health) (animal intake) Mark Kennedy, Ozarkian, 2007 Plant Growth and Management: During grazing periods: control stubble height •not too low—keep growing points •not too low—good photosynthesis for regrowth •not too low—keep roots growing •not too low – maintain bite size for intake Between grazing periods: schedule rest periods •allow photosynthesis •allow leaves to regrow to proper heights •not too long or forage quality declines Plant Growth and Management: • Example: 12 paddock system • Grazing period 2 day 3 day • Rest Period 22 day 33 day Flexibility! 4 day 44 day Matching Forage and Animal Resources Enterprises with higher potential net return require higher quality pasture and more intensive management Greater forage yield per acre Forage quality should be better Management must be more intensive Number of paddocks should be greater Matching forage and livestock resources Economic potential of grazing enterprises Pasture-based dairy/Beef finishing Dairy replacements /Beef stockers Sheep and goats, Cow-calf, Horses Paddock #’s So how many paddocks do I need? It depends length of grazing period desired producer goals, livestock performance length of rest period needed Changes seasonally rest period grazing period + # herds = paddock # Grazing period Needs Plant based: 2 - 5 days fast grow 5 - 9 days moderate 9 - 12 slow growth Animal performance: .5 - 1 day dairy cows/finishing 1 - 2 days growing/fattening 2 - 5 days lactating beef cattle, sheep, horses 4000 3500 3000 2500 2000 1500 1000 500 0 Impact of Days on Paddock on Organic Matter Intake 30 Stem Leaf 1 2 3 4 5 6 7 8 9 10 11 12 13 Days on Pasture OM Intake (lb/hd/day) DM Available (lb/acre) Impact of Days on Paddock on Change in Sward Composition 25 20 15 10 5 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Days on Pasture Rest period needs Rest period needs: 15 - 20 days during rapid growth 20 - 30 days during moderate growth 30 - 45 days during slow growth 40 - 60 days very slow growth How many paddocks do I need? Paddock Number = rest period grazing period + 1 Ex: 20 day rest period - spring 2 day grazing period +1 = 11 40 day rest period - summer 2 day grazing period + 1 = 21 How many paddocks do I need? Or: 40 day rest period 4 day grazing period + 1 = 11 Optimum Paddock #’s based on Livestock Type (Rule of Thumb) Livestock type Grazing Period (Days) Paddock # Dairy/grass finishing 0.5 – 1 20 - 80 Dairy heifer / beef 1 - 2 stockers 16 - 40 Cow/calf, Sheep, Goats, Horses 8 - 16 2-5 Summary Animals delight most to feed on fresh plants Animals supplied with this kind of food would be quickly fatted If a farmer divided his land into 15 - 20 equal divisions, Stopped his beasts from roaming indiscriminately Put the whole number of his beasts into one of these divisions Have the number of beasts so great as to consume the best part of the grass in one day Summary cont’d: Give them a fresh park every morning to repeat the same repast Have so many parks as days required to advance the grass to the proper length after being eaten fare down So the first park would be ready to receive them after going over all the others So they might be carried round in a constant rotation James Anderson, Scottish Agriculturalist, 1777 The End The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. 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