Grazier s Arithmetic. Wesley Tucker University of Missouri Extension Agriculture Business Specialist

Transcription

1 Grazier s Arithmetic Wesley Tucker University of Missouri Extension Agriculture Business Specialist

2 With MiG the end product is greater than the sum of all the parts

3 Overview Carrying Capacity Stock Density Paddock Size Stockpiling Paddock Numbers

4 Some Useful Definitions 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.

5 Carrying capacity of pasture is determined by four factors Carrying Capacity = Forage Production (lb) X Daily Intake (%) X Seasonal Utilization Rate (%) Length of the Grazing Season (days)

6 Carrying capacity of pasture is determined by four factors Carrying Capacity = Yearly Forage Production (lb) X Daily Intake (%) X Seasonal Utilization Rate (%) Length of the Grazing Season (days)

7 Carrying capacity of pasture is determined by four factors (cont.) Annual forage production Plant species present - annuals, perennials,grasses,legumes Yield distribution-fill in the gaps Plant/site suitability Fertilization Pasture condition-health, vigor, density Grazing management-good photosynthesis, good roots WEATHER- the ever changing variable }Diversity

8 Grazier s Arithmetic Carrying capacity Example: Stocker operation(buying 500# selling 800#) 200 day seasonal grazing (April 1 - Oct. 20) 12 paddock system (2-3 day grazing period) 8000 lb. total forage production (from history/experience or soil survey)

9 Grazier s Arithmetic Carrying Capacity = Forage Production Daily Intake X X Seasonal Utilization Rate Length of the Grazing Season If: Forage production = 8000 lb/acre/year Seasonal utilization = 65 % Daily intake = 3% (.03 lb forage/lb liveweight) Length of grazing season = 200 days...

10 Grazier s Arithmetic Then. Carrying Capacity = 8000 lb/acre X lb forage/lb liveweight X 200 days = 867 lb liveweight / acre

11 Grazier s Arithmetic 867 lbs. per acre/500 lb = 1.73 steers/ac Can we stock 1.73 steers/ac initially? Remember, we hope they grow! If we expect them to grow to 800 lb. then = 1300/2 = 650 (avg wt) 867/650 = 1.33 steers/ac

12 Forage yield Legume/Tall Fescue Mix Fertilization Legume Herd feed requirement April June August October

13 Carrying capacity of pasture is determined by four factors (cont.) Carrying Capacity = Forage Production Daily Intake X X Seasonal Utilization Rate (%) Length of the Grazing Season

14 Carrying capacity of pasture is determined by four factors (cont.) Seasonal utilization rate Length of grazing period and frequency of grazing Location and distance to water Duration of the grazing season Type of livestock Single livestock species vs. multiple species

15 Grazing Period Length Affects Utilization

16 Grazing Efficiency Grazing Efficiency - Total season # Grazing Utilization Pastures Period Rate 1 pasture Continuous 30% 4 pasture 7-10 days 35% 8 pasture 3-5 days 50% 12 pasture 2-4 days 65% 24 pasture 1-2 days 70 + %

17 Temporal utilization rate (%) Figure 1. Impact of distance from water on temporal utilization rate in rectangular 10 acre paddocks Rectangular paddock R-square= Distance from water (ft)

18 Carrying capacity of pasture is determined by four factors (cont.) Carrying Capacity = Forage Production Daily Intake (%) X X Seasonal Utilization Rate Length of the Grazing Season

19 Carrying capacity of pasture is determined by four factors (cont.) Daily intake requirement Dietary intake determines performance 75% forage availability : 25% forage quality Time spent grazing Biting rate Bite size

20 Relative Intake Effect of forage availability on the relative dry matter intake of cattle and sheep Cattle intake Sheep intake Forage Availability

21 The Yield - Quality Compromise Protein/energy Intake Availability Intake Fiber/lignin Optimum grazing

22 Forage Quality Pumpkin Pies or Wedding Cakes?

23 Carrying capacity of pasture is determined by four factors (cont.) Carrying Capacity = Forage Production Daily Intake X X Seasonal Utilization Rate Length of the Grazing Season (days)

24 Carrying capacity of pasture is determined by four factors (cont.) Length of the grazing season For cow-calf, sheep, goats think 365 days Short-season stockers offer more flexibility Dairy day quality grazing

25 Cow/Calf Example 8000 lb/ac X lb forage/lb liveweight X 365 days = 256 lb liveweight/ac or 4.68 ac/cow Carrying Capacity = 8000 lb/acre X lb forage/lb liveweight X 365 days = 475 lb liveweight / ac or 2.52 ac/cow

26 Grazier s Arithmetic Carrying capacity Stock density

27 Some Useful Definitions Stocking rate: The number of animals or animal liveweight assigned to a grazing unit on a seasonal basis. Stock density: The number of animals or animal liveweight assigned to a specific pasture area for a specific time period. Stock density is a powerful tool to manage grassland resources (improve utilization, reduce spot grazing/selectivity, control competition, manure distribution, produce seed/soil contact, open up a sward for overseeding)

28 What is Stock Density?? Let s say we have 40 head of 1250 lb cows That is 50,000 lbs of beef on the hoof.

29 50,000 lbs Beef (40 cows) 10 acres

30 Stock Density 50,000 lbs Beef (40 cows) 10 acres = 5000 lbs live weight / acre

31 Stock Density 50,000 lbs Beef (40 cows) 10 acres = 5000 lbs live weight / acre 50,000 lbs Beef (40 cows) 1 acre

32 Stock Density Stock Density 50,000 lbs Beef (40 cows) 10 acres = 5000 lbs live weight / acre 50,000 lbs Beef (40 cows) 1 acre = 50,000 lbs live weight / acre

33 Stock Density Stock Density 50,000 lbs Beef (40 cows) 10 acres = 5000 lbs live weight / acre 50,000 lbs Beef (40 cows) 1 acre = 50,000 lbs live weight / acre 50,000 lbs Beef (40 cows) 1/4 acre

34 Stock Density Stock Density 50,000 lbs Beef (40 cows) 10 acres = 5000 lbs live weight / acre 50,000 lbs Beef (40 cows) 1 acre = 50,000 lbs live weight / acre Stock Density = 50,000 lbs Beef (40 cows) 1/4 acre 200,000 lbs live weight / acre

35 A picture is worth a thousand words.

36 A picture is worth a thousand words.

37 Stock density of pasture is determined by four factors Stock Density = Forage Availability (lb) Daily Intake X X Grazing Period Utilization Rate Length of the Grazing Period

38 Stock density of pasture is determined by four factors (cont.) Available forage (Get out the Grazing Stick) How much forage is available on this acre this day Can be estimated from height If too little, intake will be restricted If too much, quality may be low/intake restricted

39 Dry matter yield per acre-inch for various pasture types Stand Density Forage 60-75% 75-90% >90% Tall Fescue + N Tall Fescue + legumes Bromegrass + legumes Orchardgrass+legumes Bluegrass+ whiteclover Mixed pasture Bermudagrass Caucasian Bluestem Native Warm Season Grasses Red Clover/Alfalfa

40 Stock density of pasture is determined by four factors (cont.) Stock Density = Forage Availability Daily Intake X X Grazing Period Utilization Rate (%) Length of the Grazing Period

41 Stock density of pasture is determined by four factors (cont.) Temporal utilization rate Take half, leave half Utilization greater than 50% stops root growth Length of grazing period is critical factor As utilization increases, intake decreases

42 Corresponding Root Growth % Leaf Removed % Root Growth Stopped to

43 Stock density of pasture is determined by four factors (cont.) Stock Density = Forage Availability Daily Intake (%) X X Grazing Period Utilization Rate Length of the Grazing Period

44 Grazier s Arithmetic Forage Intake Rate in % of body weight Dry Cow 2-2.5% Lactating Cow 3-4% Dairy Cow % + grain Stockers % Sheep 3.5-4% Horse 2.5-4%

45 Stock density of pasture is determined by four factors (cont.) Stock Density = Forage Availability (lb) X Daily Intake (%) X Grazing Period Utilization Rate (%) Length of the Grazing Period (days)

46 Stock density of pasture is determined by four factors (cont.) Length of the grazing period Stock density increases with shorter grazing periods Animals are concentrated on smaller areas for a shorter amount of time Selectivity decreases Utilization increases

47 Grazier s Arithmetic Stock Density = Forage Availability Daily Intake X X Grazing period Utilization Rate Length of the Grazing Period If: Available forage = 2400 lb/acre 300 lb./in) Temporal utilization = 50 % Daily intake = 3% (.03 lb forage/lb liveweight) Length of grazing period = 1 days...

48 Grazier s Arithmetic Then. Stock Density = 2400 lb/acre X lb forage/lb liveweight X 1 days = 40,000 lb liveweight / acre

49 Grazier s Arithmetic 40,000 lb liveweight/ac/650 lb avg wt = 61.5 steers/ac if moving daily or 20,000 lb = 30.7 steers/ac if moving every 2 days 13,333 lb = 20.5 steers/ac if moving every 3 days

50 Grazier s Arithmetic Carrying capacity Stock density Size of paddock

51 Grazier s Arithmetic Stockpiling VERY practical example: Figure paddock (or strip) size needed for a herd of dry beef cows on stockpiled fescue Ac. = Daily Intake X # Head X Grazing Period Forage Available X Utilization Rate

52 Grazier s Arithmetic How much will they eat? 1200 lb dry cow needs?

53 Grazier s Arithmetic Forage Intake Rate in % of body weight Dry Cow 2-2.5% Lactating Cow 3-4% Dairy Cow % + grain Stockers % Sheep 3.5-4% Horse 2.5-4%

54 Grazier s Arithmetic How much will they eat? 1200 lb dry cow needs 2.5% of body weight per day 1200 * 2.5% = 30 lb How many head? Use 40 How long is the grazing period? Use 2 days

55 Grazier s Arithmetic How much forage is available? Tall fescue + N Average height is 10 inches

56 Grazier s Arithmetic Forage 60-75% 75-90% >90% Tall Fescue + N Tall Fescue + legumes Bromegrass + legumes Orchardgrass+legumes Bluegrass+ whiteclover Mixed pasture Bermudagrass Caucasian Bluestem Native Warm Season Grasses Red Clover/Alfalfa

57 Grazier s Arithmetic How much forage is available? Tall fescue + N Average height is 10 inches At 400 lb/in. we have 4,000 lb. What is the temporal utilization rate?

58 Grazing Efficiency Grazing Efficiency - Total season # Grazing Utilization Pastures Period Rate 1 pasture Continuous 30% 4 pasture 7-10 days 35% 8 pasture 3-5 days 50% 12 pasture 2-4 days 65% 24 pasture 1-2 days 70 + %

59 Grazier s Arithmetic How much forage is available? Tall fescue + N Average height is 10 inches At 400 lb/in. we have 4,000 lb. What is the utilization rate? Use 70 %

60 Grazier s Arithmetic Ac. = Daily Intake X # Head X Grazing Period Forage Available X Utilization Rate Ac = 30 X 40 X 2 = 2400 =.86 acre 4000 X 70% 2800 You can develop a shortcut for your operation AFTER you ve gone through this calculation.

61 Overview Carrying Capacity Stock Density Paddock Size Stockpiling Paddock Numbers

62 Grazier s Arithmetic: How many paddocks do I need? It depends length of grazing period desired producer goals, livestock performance length of rest period needed rest period grazing period + 1 = paddock #

63 Grazier s Arithmetic: Grazing period Needs Plant based: 2-5 days fast grow 5-9 days moderate 9-12 slow growth As short as needed to prevent any grazing of regrowth!!! Animal performance:.5-1 day dairy cows 1-2 days growing/fattening 2-4 days lactating beef cattle, sheep, horses 4-7 days dry animals

64 Grazier s Arithmetic: Grazing period Needs Plant based: 2-5 days fast grow 5-9 days moderate 9-12 slow growth As short as needed to prevent any grazing of regrowth!!

65 Grazier s Arithmetic: Grazing period Needs Plant based: 2-5 days fast grow 5-9 days moderate 9-12 slow growth As short as needed to prevent any grazing of regrowth!!

66 Yield (tons/a) days days days Rest Period Needs: Grazing Season 1.5 GRASS LEGUME Spring Summer Fall

67 Grazier s Arithmetic: How many paddocks do I need? Paddock Number = rest period grazing period + 1 Ex: 20 day rest period - spring 3 day grazing period + 1 = 8 40 day rest period - summer 3 day grazing period + 1 = 14

68 Grazier s Arithmetic: How many paddocks do I need? Or: 40 day rest period + 1 = 9 5 day grazing period

69 Fixed/Flexible System Design 9 paddock fixed system Flexible paddock numbers in hayfields and/or warm season grass Water available in every paddock Alleyway for ease of livestock movement Hay & graze Temporary fence for grazing Warm season grass Hay & graze Very flexible, workable system

70 How many paddocks? Economic potential of grazing enterprises Pasture-based dairy Dairy replacements Paddock # s Beef stockers Sheep and goats Cow-calf

71 Optimum Paddock # s based on Livestock Type (Rule of Thumb) Livestock type Grazing Period (Days) Paddock # Dairy Dairy Heifer Stockers Cow/calf, Sheep, Goats, Horses

72 Flexibility The ability to adapt or modify, being responsive to changing conditions Grazing management strategies must be flexible Remember, we re always shooting at a moving target!

73 The end