Marianas Grazing and Livestock Management Academy Range ... · Slide 1 . Mark S. Thorne, Ph.D....

Mark S. Thorne, Ph.D.University of Hawaii at Manoa - Cooperative Extension ServiceCollege of Tropical Agriculture and Human Resources

Funding Provided by:USDA-National Institute of Food and Agriculture; Outreach and Assistance for Socially Disadvantaged Farmers and Ranchers – Grant # 2009-51200-19601

Marianas Grazing and Livestock Management AcademyRange and Pasture Management 101:Range and Pasture Animal Nutrition

Range and Pasture Animal Nutrition I) Cattle Annual Production Cycle/Nutritional demands

• Biological and chronological cycle of the beef cow B) Cattle production cycle depicted by George et al. 2001, figure 1. • Nutrient demands are dynamic, physiological state is the most important cause for changes in demand • Lactation has highest nutrient demands, 2nd trimester the least E) George et al. 2001, table 2.

i) An example of changing nutritional demands of a 1000 lb beef cow depending on physiological state. ii) Relationship of body size to maintenance energy needs. Body size also affects how much energy and

nutrients are required by the animal. II) Micro/Macronutrients, other necessities

• Introduction - Proper nutrition for healthy animals B) Energy (TDN), Protein • Important minerals/nutrients for production D) Effects of deficiencies, common deficiencies

III) Annual Forage Production Cycle • Stages forage of growth • Nutrient composition of different HI forages from the Hawaii Forages C) Interpreting a forage analysis report (Dairy One factsheet; Redfearn et al.; CL305).

IV) Synchronizing forage and animal production A) Observing their performance. • Body Condition Scoring (BCS) C) What is BCS? D) BCS scale (adapted from Momont and Pruitt, CL720 and Elanco Animal Health publication AI 8301). E) Why does BCS matter? F) Managing for BCS (adapted from Bruce et al. 1999, chapter 2). G) Factors affecting calving season (George et al. 2001, pg 1).

V) Effective Nutrient/Energy Supplementation (CL303; CL327) A) Daily needs for energy, protein, Ca, and P for lactating and dry cows (Sprinkle 1996, table 1 pgs 1-2). B) Determine costs of supplementation program (Sprinkle 1996, pg 4; CL316).

Annual Production Cycle: Cattle Biological and Chronological Production Cycle

Biological Cycle Day Chronological Cycle

1st Trimester Begins 1 June 1: Conception

2nd Trimester Begins 94 Sept. 3: End 1st Trimester

3rd Trimester Begins 188 Dec. 6: End 2nd Trimester

Postpartum: Lactation 282 March 9: Birth of calf

Rebreeding: Lactation 365 June 1: Conception

Lactation Ends 488 Oct. 1: Calf weaned

Source: Bruce et al. 1999, table 1.1

I) Cattle Annual Production Cycle/Nutritional demands A) Biological and chronological cycle of the beef cow (Bruce et al. 1999, table 1.1).

Annual Production Cycle: Cattle Biological and Chronological Production Cycle

Source: George et al. 2001, figure 1

B) Cattle production cycle depicted by George et al. 2001, figure 1.

Annual Production Cycle: Nutrient Demands

Source: Bruce et al. 1999, figure 1.2

C) Nutrient demands are dynamic, physiological state is the most important cause for changes in demand (Bruce et al. 1999, figure 1.2 graph of generalized protein and energy demands of a cow during lactation and pregnancy; for more info see CL330).

D) Lactation has highest nutrient demands, 2nd trimester the least (see Bruce et al. 1999, table 4.1; CL300 has NRC 1984 values for nutrient requirements of cows of different classes).


Nutrient Requirements for a 1,000 lb beef cow.

Stage of Production

Nutrient

Period 1: Calving

(45 days)

Period 2: breeding (45 days)

Period 3: early

gestation (90 days)

Period 4: mid

gestation (90 days)

Period 5: late

gestation (90 days)

Dry matter (lb) 20.6 21 19.5 18.1 19.6

Protein (lb/day) 2.5 2.6 2 1.3 1.6

TDN (lb) 13.8 14 11.5 8.8 10.5

Calcium (g/day) 36 38 25 15 23

Phosphorus (g/day) 25 27 20 15 18

Vitamin A (x1000 IU) 37 38 36 25 31

Source: George et al. 2001/National Resource Council 1984

E) George et al. 2001, table 2. i) An example of changing nutritional demands of a 1000 lb beef cow depending on physiological state.


Source: Bruce et al. 1999, figure 1.1

ii) Relationship of body size to maintenance energy needs (Bruce et al. 1999, figure 1.1). Body size also affects how much energy and nutrients are required by the animal.

Essential Nutrients

Important Minerals, Nutrients, and Vitamins for Production:

• Energy• Protein• Sodium (NaCl)• Phosphorus (P)• Calcium (Ca)• Iodine (I)• Potassium (K)

• Magnesium (Mg)• Selenium (Se)• Cobalt (Co)• Iron (Fe)• Copper (Cu)• Vitamin A• Vitamin D

II) Micro/Macronutrients, other necessities A) Introduction - Proper nutrition for healthy animals means nutrient levels adjusted for metabolic needs for

maintenance, growth, reproduction, and lactation. No single nutrient is responsible for a healthy immune system and growth. Nutrients interact with each other and can have antagonistic as well as positive effects (Bruce et al. 1999, pg 60-65).

B) Energy (TDN), Protein i) Energy is often measured as Total Digestible Nutrients and is one of the most important nutritional

factors for beef cows. Energy is necessary for rapid growth of immune cells. ii) Proteins are used in the structure of cells and thus replication and synthesis of antibodies and other

materials of the immune system. C) Important minerals/nutrients for production (Bruce et al. 1999, chapter 9, table 9.1). i) NaCl, P, Ca, I, K, Mg, Se, Co, Fe, Cu ii) Vitamins A (carotene) and D D) Effects of deficiencies, common deficiencies (Bruce et al. 1999, pgs 65-67; George et al. 2001, table 3). i) Energy – retarded growth, delayed sexual maturity, poor conception rate, loss of body weight, lowered

resistance to parasites, decline in milk yield. ii) Protein – reduced appetite, reduced growth rate, loss of weight, delayed estrus, poor conception, poor

milk yield. iii) NaCl – loss of appetite, unthrifty appearance, weakness, lack of coordination. iv) Vitamin A – susceptibility to infection, abortion, scouring, night blindness.

Annual Forage Production Cycle: Season of Growth

Sour

ce: B

ruce

et a

l. 19

99, f

igur

e 4.

1

III) Annual Forage Production Cycle A) Stages of growth (Season) i) Forage quality over time (Bruce et al. 1999, figure 4.1). Forage quality (relative amount of digestible nutrients) declines as season progresses. In other words, flowering/fruiting plants are lower quality than fresh vegetative (leaf) growth.

Annual Forage Production Cycle: Growth Form

Sour

ce: B

ruce

et a

l. 19

99, f

igur

e 4.

2C3

C4

Maintenance

B) Stages of growth (Season, continued) ii) Metabolizable energy in forages declines as plants mature with grasses and forbs having higher amounts

of energy relative to browse (brush species).

Annual Forage Production Cycle: Growth Form

Sour

ce: B

ruce

et a

l. 19

99, f

igur

e 4.

3

A) Stages of growth (Season, continued) iii) Digestible protein in forages similarly declines as plants mature with browse maintaining higher amounts of protein than forbs and grasses respectively.

Nutrient Composition of Hawaii Forages: 12 weeks growth

Species

Dry Matter

(%)Yield (lb/ac)

Crude Protein

(%)ADF (%)

P (%)

K (%)

Ca (%)

Mg (%)

Na (%)

Mn (ppm)

Fe (ppm)

Kikuyu (Whittet) 22.12 1498.3 8.56 35.68 0.27 0.99 0.39 0.33 0.06 57.78 1519.78

Guinea grass (Natsukaze) 24.26 1633.6 8.08 40.7 0.16 1.64 0.7 0.22 0.09 135 3288

Blue Pangola 22.41 1522.8 7.62 39.96 0.19 1.3 0.7 0.29 0.08 71.67 1784.89

California grass 21.12 2793.5 6.43 40.6 0.17 0.71 0.42 0.25 0.51 84 1499.56

Signalgrass 25.69 1677.3 7.78 35.39 0.22 0.62 0.92 0.48 0.05 88.22 1475.89

Puerto Rican Star 30.55 1649.8 8.08 38.69 0.18 1.27 0.53 0.2 0.08 53.22 1164

Source: www.ctahr.hawaii.edu/ctahr2001/InfoCenter/Forages/grasses.html

B) Nutrient composition of different HI forages from the Hawaii Forages website <http://www.ctahr.hawaii.edu/ctahr2001/InfoCenter/Forages/grasses.html>. Average nutrient and yield values for samples taken from the Mealani Forage Demonstration Garden. i) Kikuyu ii) Guinea grass iii) Pangola iv) California grass v) Signal grass vi) Puerto Rican Star Refer back to the table in slide 5. A 1000 lbs cow requires 2.5 lbs of protein per day in a 20.6 lbs dry matter diet. Referring to the table above how much protein would a twelve week old kikuyu grass pasture supply (20.6 x 0.0856 = 1.8 lbs of CP); one AU (1000 lb cow w/calf; 26 lbs dry matter per day) will get 2.2 lbs CP. Clearly, 12 week old grass growth is not sufficient to meet the nutritional demands of lactating cows. Slide 12

Annual Forage Production Cycle: Interpreting a Forage Analysis Report

Common Elements of a Forage Analysis Report:

• % Dry Matter (DM)

• Crude Protein (CP)

• Neutral Detergent Fiber (NDF)

• Acid Detergent Fiber (ADF)

• Total Digestible Nutrients (TDN)

• Relative Feed Value (RFV)

Interpreting a forage analysis report (Dairy One factsheet; Redfearn et al.; CL305). % Dry matter - includes protein, fiber, fat, minerals, etc.. Animals consume feeds to meet their dry matter

needs, which contains all of the nutrients. Animals will have to consume more of a wetter feed to receive the same amount of dry matter as they would from a drier feed. It is important to know the dry matter content of a feed to establish feeding rates and insure that livestock receive the amount of feed to meet their daily needs. Crude Protein (CP) - the total protein in the sample. Proteins are a major component of vital organs, tissue, muscle, hair, skin, milk and enzymes. Protein is required on a daily basis for maintenance, lactation, growth and reproduction. Neutral Detergent Fiber (NDF) - a measure of hemicellulose, cellulose and lignin representing the fibrous bulk of the forage. These three components are classified as cell wall or structural carbohydrates. They give the plant rigidity enabling it to support itself as it grows, much like the skeleton in animals. Hemicellulose and cellulose can be broken down by microbes in the rumen to provide energy to the animal. NDF is negatively correlated with intake. Acid Detergent Fiber (ADF) - a measure of cellulose and lignin. Cellulose varies in digestibility and is negatively influenced by the lignin content. As lignin content increases, digestibility of the cellulose decreases. ADF is negatively correlated with overall digestibility. Total Digestible Nutrients (TDN) - denotes the sum of the digestible protein, digestible NSC, digestible NDF and 2.25X the digestible fat. Relative Feed Value (RFV) - an index for ranking forages based on digestibility and intake potential. A RFV of 100 is considered the average score. The higher the RFV, the better the quality.

Synchronizing Forage and Animal ProductionAre my animals getting enough from my forage?

Ask them!

IV) Synchronizing forage and animal production A) One of the best ways to tell if animals’ nutritional needs are met is by observing their performance. B) Body Condition Scoring (BCS) is a tool for estimating animal performance.

Synchronizing Forage and Animal Production: Body Condition Score (BCS)

Liveweight% Fat

Sour

ce: E

lanc

o A

nim

al H

ealth

, AI 8

301

C) What is BCS? i) Simply stated: BCS is a quick, structured visual estimate of an animal’s physical state given on a scale

from 1-9. D) BCS scale (adapted from Momont and Pruitt, CL720 and Elanco Animal Health publication AI 8301). 1 - 2: Emaciated to severely emaciated. Shoulder, ribs, backbone, hooks, and pins visible with little to no

muscling and fat in the hindquarters. 3: Caution, very thin with no fat on ribs or brisket. Backbone easily visible. 4-6: Optimal range. Thin to good smooth appearance throughout. Last two to three ribs visible or covered

with some fat deposits in brisket and over the tailhead. Hindquarters may appear rounded. 7: Caution, brisket full and ribs smooth. Fat cover is thick and spongy. 8-9: Obese to very obese (rare). Hindquarters have square appearance and heavy fat pockets around

tailhead. Mobility may actually be impaired (rare).


An animal’s body condition strongly affects reproduction, parturition, and rebreeding success.

Tabl

e: S

prin

kle

2000

, Dat

a: S

pitz

er e

t al.

1996

E) Why does BCS matter? i) An animal’s BCS is directly related to pasture/feed quality and strongly affects animal reproductive success.


• Bulls and cows should be at BCS 5-6 for best fertility rates.

• First-calf heifers and second calf cows should be BCS 6-7.

• A change in condition score is equivalent to at 60 –80 pound change in weight. Plan accordingly!

E) Why does BCS matter (cont’d)? ii) Researchers have reported strong correlations between BCS and percent body fat of cows. iii) Simply put, cows of higher BCS (between 5 and 7) at calving and during early lactation are more likely

to cycle and become pregnant early in the breeding season or within the window to maintain an annual production cycle. The converse is also true.

Synchronizing Forage and Animal Production: Managing for Body Condition Score (BCS)

• Group animals of similar body condition.

• Reevaluate BCS3-4 months before breeding season.

• Evaluate returns form a higher calving rate compared to cost of supplementing and feed accordingly if necessary.

F) Managing for BCS (adapted from Bruce et al. 1999, chapter 2). i) Having cows and first-calf heifers at a BCS of 5 or above increases the probability of a higher calving

rate. ii) Remember that how an animal looks now is a reflection of pasture/feed conditions of the preceding

months. In other words, current pasture conditions will be reflected in an animal’s BCS a few months from now.

iii) Give yourself plenty of time to raise an animal’s BCS. An increase of 10% dietary TDN equates to 1 pound of gain per day which would move an animal up one BCS score within 3 months (60-90 pounds). Also, the payoff from a difference between a BCS 5 and 6 may not be worth the cost of feeding. Maintaining is easier than catching up!

Factors Affecting Calving Season:

• Quality and availability of forage

• Weather conditions

• Supplemental feed

• Labor

• Capital inputs

• Calf crop production goals

• Disease

Synchronizing Forage and Animal Production: Calving Season

G) Factors affecting calving season (George et al. 2001, pg 1). i) The reproductive year of a beef cow is very tight. The period from conception to birth is about 283 days

(9.4 months), and most cows will not be ready to rebreed until 30-45 days after calving (longer is nutrition is poor). A cow-calf producer only has a window of about 42 days to successfully rebreed a cow to stay on an annual calf producing cycle (George et al. 2001, pg 2).

ii) In other words, as the nutritive needs of a cow are highest during lactation, plan for a calving season when forage is of high enough quality to maintain the cow’s BCS for rebreeding. You cannot expect to increase a cow’s BCS while she’s lactating, but on quality pasture you can keep her from slipping too much too fast for rebreeding purposes.

Effective SupplementationThe object of supplementation programs is to match forage quality deficiencies so as to increase forage intake by the animal.

Supplements need to be designed not only for the nutritional health of the herd but also for the profitability of the operation.

Evaluation of the herd:

Key indicators = GOLDcalf GrowthOpen cowsLength of calving seasoncalf Death loss

If any of these indicators are below industry standard nutrition is not adequate – nutrient or energy supplementation maybe necessary.

V) Effective Nutrient/Energy Supplementation (CL303; CL327) A) Daily needs for energy, protein, Ca, and P for lactating and dry cows (Sprinkle 1996, table 1 pgs 1-2). B) Determine costs of supplementation program (Sprinkle 1996, pg 4; CL316).

SummaryRange and Pasture animal nutrition is a function of the grazing animals nutritional needs and the quantity and quality of the forages over time.

The nutritional requirements of the grazing animal are defined by the kind and class of animal, their physiologic status, and the age of the animal.

The quality and quantity of forage available for the grazing animal changes over time, is influenced by the environment, and can be affected by previous grazing events.

Maintaining herd productivity requires matching the animal nutritional demands with the available forage resources or providing supplementation to make up for deficiencies.

When is the highest nutritional demand for a cow’s normal production cycle?

During th

e 1st tri

mester

During th

e 2nd trim

ester

During La

ctatio

n

During th

e 3rd Trimeste

r

Both 3 and 4

0% 0% 0%0%0%

1. During the 1st trimester2. During the 2nd trimester3. During Lactation4. During the 3rd

Trimester5. Both 3 and 4

What is the daily protein intake for cattle consuming 26 lbs of guinea grass with a CP concentration of 8.1%?

2.1 lbs o

f Protein

1.5 lbs o

f Protein

3 lbs o

f Protein

I don’t k

now and does it...

0% 0%0%0%

1. 2.1 lbs of Protein2. 1.5 lbs of Protein3. 3 lbs of Protein4. I don’t know and does it

really matter?

Is the protein intake in the previous slide enough to support a lactating cow? (refer to the table in slide 5)

Yes No

0%0%

1. Yes2. No

The optimal Body Condition Score range for a mature cow at breeding time is…?

BCS 7-9; as f

at as c

an be

BCS 1-3; skin

ny make

s it...

BCS 4-6; not to

o fat, n

ot...

What is

BCS?

0% 0%0%0%

1. BCS 7-9; as fat as can be

2. BCS 1-3; skinny makes it easy for the bull

3. BCS 4-6; not too fat, not too skinny

4. What is BCS?

What is the weight difference between Body Condition Scores?

10-20 pounds

100-200 pounds

60-80 pounds

40-50 pounds

What d

ifference

?

0% 0% 0%0%0%

1. 10-20 pounds2. 100-200 pounds3. 60-80 pounds4. 40-50 pounds5. What difference?

What does the acronym GOLD stand for when evaluating herd nutritional health?

Good cows, O

ld cows, L

a..

Nothing, GOLD

is a se

mi...

calf G

rowth, Open co

ws,...

0% 0%0%

1. Good cows, Old cows, Lazy cows, Damn cows.

2. Nothing, GOLD is a semi-hard yellow metal used for money and teeth.

3. calf Growth, Open cows, Length of calving season, calf Death loss.

Marianas Grazing and Livestock Management Academy Range ... · Slide 1 . Mark S. Thorne, Ph.D....

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