Transcript Document

Ruminant Animal Feed
Management Issues and
Practices
CNMP Core Curriculum
Feed Management – Section 6.2
CNMP Development
Core Training Curriculum
These course materials have been developed as a
cooperative effort between five land-grant universities
and The Natural Resources Conservation Service.
Copyright Information
Ames, Iowa 50011, (515) 294-4111.
Copyright © 1995-2006, Iowa State University
of Science and Technology. All rights reserved.
Objectives
•
Diet composition for ruminants
•
Review digestion processes and excretion
of N and P of the ruminant
•
Discuss aspects of ration balancing
•
Discuss reasons for overfeeding of
nutrients
•
Provide strategies for reducing nutrient
excretion
Supplemental Materials
• NRC Nutrient Requirements of Dairy Cattle
• NRCS Nutrient Management Technical Note 5
• LPES Lesson No. 12 Feeding Dairy Cows to
Reduce Nutrient Excretion NRC Nutrient
Requirements of Beef Cattle
• NRCS Nutrient Management Technical Note 2
• LPES Lesson No. 13 Using Dietary Strategies
to Reduce the Nutrient Excretion of Feedlot
Cattle
Ruminant Nutrition
You are NOT just feeding the steer or
cow! You are also feeding the
microorganisms in the rumen.
You must feed and meet the needs of
the ruminal microorganisms and the
animal.
Dairy Diets
Digestibility (availability of nutrients) of forages:
• Amount of forage
• Type of forage
• Maturity of forage
Higher digestibilities increase utilization
and
decrease nutrient excretion.
Lower digestibilities
decrease utilization and increase nutrient
excretion.
Dairy Diets
Concentrates
45-60
Grains (corn, milo, barley, etc)
Protein meals (soybean meal, Soypass,
Cottonseed, distillers grains, etc.)
Byproducts (corn gluten feed, beet pulp,
soyhulls, etc.)
Forages
40-55
alfalfa hay, corn silage, haylage, grasses
grazing?
Supplement
dry-pellet, dry-meals, liquid
minerals, protein?, vitamins, additives
2-10
Relationship between advancing maturity
of first cut orchard grass and chemical
composition.
400
350
300
250
Cellulose
CP
Lignin
200
150
100
50
0
14-Apr
24-Apr
4-M ay
14-M ay 24-M ay
Date
3-Jun
13-Jun
TSP Question to Producer
• How do you manage your forages?
• Buy or home grown?
• Are you maximizing the amount of home
grown forages in the ration?
Feedlot Diets
Corn/Milo
High-moisture
Dry-rolled
Steam-flaked
Whole
Roughage (alfalfa hay, corn silage)
Byproducts (distillers/gluten feed)
Molasses/Liquid
Supplement
dry-pellet
liquid
50-85
0-10
15-40
0-5
3-8
A Few Terms and Definitions
• Crude protein (CP) = N x 6.25
• Some protein is used by microorganisms in
rumen and some are absorbed in small
intestine
• Rumen degradable protein (RDP) = CP that
is degraded in the rumen; required by
bacteria to grow (DIP in beef)
• Rumen undegradable protein (RUP) =
“escape or bypass” CP that is NOT degraded
in rumen but passes to lower tract (UIP in
beef)
Digestive Process of Ruminants
Sm Intestine
Fecal N
Urea
Rumen
AAMCP MCP
AA
RUP
Ammonia
BUN
Milk
and
Meat
Milk Urea N
RDP
NPN
Degraded by
microorganisms
Diet CP
Ruminant Nutrition
Protein
• Goals
– Provide adequate amount of rumen
degradable protein:
• For optimal rumen health
• For optimal rumen efficiency
– Provide adequate amount of rumen
undegradable protein:
• To obtain the desired animal productivity
Ruminant Nutrition
Protein
• Excess N excretion typically due to
imbalance of RDP and RUP and too much
of one, or both
– Excess RDP increases ammonia production
in rumen which leads to:
• Decrease reproductive performance (toxic effect)
• Decrease lactation performance (energy cost)
• Increases urinary N excretion
– Excess RUP:
• Not utilized by animal
• Increases fecal and urine N excretion
Intake
Retention
Excretion
Intake-Retention=Excretion
Excretion in feces & urine
Ruminant Nutrition
Protein
• Estimate N excretion (dairy):
– Milk production
– Days in milk
– Dry matter intake
– Body weight
– Milk protein content
– Concentration of CP in ration
Ruminant Nutrition
Protein
• Estimate N excretion (beef):
– Dry matter intake
– Concentration of CP in ration
– Days on feed for individual ration
– Purchase weight (initial weight)
– Market weight (ending weight)
– Standard reference weight for expected final
body fat
2-year beef study
(protein level)
Overfeeding protein increases N losses!
Nutrition may:
decrease N inputs by 10 to 20%
reduces N excretion by 12 to 21%
reduces N volatilization by 15 to 33%
Based on annual occupancy, lose 50% of N
excreted
• 53.5% annually for control animals, or 103
g/hd/d
• 48.2% annually for phase-fed animals, or 78
g/hd/d
Digestive Process of Ruminants
Phosphorus
Sm Intestine
Fecal
P
Excess P
Rumen
Salivary P
Productive
functions
Milk
(0.085 to 0.1%)
M/O
Diet P
Ruminant Nutrition
Phosphorus
• Estimated P excretion (dairy):
– Dry matter intake
– Amount of P in ration
– Milk production
– Amount of P in milk (~ 0.10%)
Ruminant Nutrition
Phosphorus
• Estimated P excretion (beef):
– Dry matter intake
– Concentration of P in ration
– Days on individual ration
– Purchase weight (initial weight)
– Market weight (final weight)
– Standard reference weight
TSP Question to Producer
• Are the rations reformulated when there are
different ingredient changes?
• Are rations changed at different stages in the
production cycle?
• What is the laboratory analysis schedule for
the feed management plan?
• Are by-product feeds being used in the ration?
% diet P (DM-basis)
Dietary P in Feedlot Diets
0.7
0.6
0.5
0.4
Supplement
Byproduct
Corn
Roughage
0.27
0.59
0.52
0.35
NRC
0.3
0.2
0.1
0
85% Corn 85% Corn + Byproduct Byproduct +
Supplement
Supplement
P requirements
4.00
3.50
ADG, lb/day
3.00
2.50
2.00
1.50
1.00
NRC
0.50
0.00
0.00
0.05
0.10
0.15
0.20
P, % of diet DM
0.25
corn
0.30
industry
0.35
0.40
P Mass Balance: Summer
Yearlings
Feedlot Pen
0.35% P diet
10.9 lb
excreted
1.9 lb
P
retained
12.8 lb P
intake
REDUCED
44%
0.24% P diet
5.3 lb
excreted
Values for the entire feeding period
1.9 lb P
retained
7.2 lb P
intake
P Mass Balance:
Winter/Spring Calves
Feedlot Pen
0.40% P diet
12.5 lb
excreted
2.5 lb P
retained
15.0 lb P
intake
REDUCED
33%
0.26% P diet
7.5 lb
excreted
Values for the entire feeding period
2.4 lb P
retained
9.9 lb P
intake
Dietary P effect on excretion
Y = 0.0111x2 + 0.0522x + 6.6726; r2 = 0.74
P excretion (g/d)
40
30
20
10
0
0
10
20
30
P intake (g/d)
40
50
Land Requirements, 4 yr P basis
(acres)
2500
10,000
25,000
0 byp 0.29 P
1,320
5,300
13,200
20 byp 0.39 P
1,900
7,600
19,000
40 byp 0.49 P
2,500
10,000
25,000
Costs and Net Value, C-SB rotation
4-Yr P Basis, ($/hd)
COSTS
0 byp 0.29 P
20 byp 0.39 P
40 byp 0.49 P
NET VALUE
0 byp 0.29 P
20 byp 0.39 P
40 byp 0.49 P
2500
10,000
25,000
3.00
3.50
3.90
2.10
2.70
3.30
3.00
4.30
5.75
2.50
4.30
6.10
3.50
5.10
6.80
2.50
3.50
4.30
Ration Balancing
Balancing Ruminant Rations
Ingredient Challenges
Book values vs Ingredient testing:
• Book values have limited value
• Ingredient testing only as good as the
sample taken
Balancing Ruminant Rations
Ingredient Challenges
“Unbreakable Law of Sampling: You never
know the true value of anything”
-Bill Weiss, OSU
Balancing Ruminant Rations
Ingredient Challenges
Numbers are not absolute!
20 tons of
feedstuff
1 lb sample
sent to lab
(1/40,000)
1 g sub-sample
analyzed
(1/18,000,000)
Balancing Ruminant Rations
Meeting the Requirements of the Herd
If herd average is 77 lbs:
 Overfeeding cows producing 55 lbs
 Excess nutrients leads to weight gain leading to health
problems and lowered production
 Underfeeding cows that could produce 120 lbs
 Not providing enough nutrients to meet genetic potential
 Not taking advantage of “money-makers”
 Fresh cows producing 77 lbs have different
requirements
 If do not meet nutritional needs of fresh cow, entire
lactation will be negatively affected: lost production and
health issues
Who do you balance the ration for?
Feeding Management:
The Bottom Line
 The milking herd should be grouped by
production level so that multiple rations
can be formulated over the complete
lactation.
 Similarly, growing feedlot beef cattle
should be grouped by sex, age and
production potential so that multiple
rations can be fed over the growth
period.
Reducing N and P Excretion
with Feed Management
Nitrogen Strategies for Dairy
• Increase dry matter uptake.
• Improve forage quality.
• Evaluate balance of types of home grown
forages and other feed ingredients
available.
• Consider forage protein fraction.
• Consider feeding method (phase and TMR).
• Consider supplemental protein source.
• Monitor blood urea nitrogen (BUN) and milk
urea nitrogen (MUN).
Beef Strategies
• Test feed for nutrients and dry matter.
• Use supplemental protein to balance
RDP and RUP.
• Discontinue supplemental P.
• Consider phase feeding.
• Use available tools to evaluate your
rations.
Questions?
P Mass Balance – Example CNMP
Manure
P2O5
Produced
= (44.82 lbs. avg. feed intake (%dm) x 0.0036*) (65 lbs. avg. milk prod. per cow/day** x
0.001***) x 2.29****
= 0.0963 lbs. P per day per cow x 2.29
= 0.22 lbs. P2O5 per day per cow x 175 cows x
365 days
= 14,094 lbs P2O5 per year
Acres
Required for P2O5 Mass
Balance
= 14,094 / 65 lbs. P2O5 removed by crop
= 217 acres X 50% confinement
= 108 acres
*0.36 % of P in total feed ration from feed analysis
**Based on 2000/2001 rolling herd average of 26700 lbs. of milk produced per
cow per year
***0.10 % of P in milk; ****conversion of P to P2O5
Class Exercise (Ruminants)
• Calculate P excretion for the example
CNMP dairy if they use 25% DDGS in
place of corn silage and milled feed.
• Calculate the amount of land needed to
apply the P2O5 (assume 65 lbs of P2O5
needed for corn silage/acre) from the
manure from cows fed this new ration
(assume that only 50% of the time the
cows are in confinement)
Class Exercise (Ruminants)
• Calculate P excretion for the example
CNMP dairy if they use 25% DDGS in
place of corn silage and milled feed.
What do you need to know?
DMI, diet composition, milk production
Class Exercise (Ruminants)
• Calculate P excretion for the example
CNMP dairy if they use 25% DDGS in
place of corn silage and milled feed.
What do you need to know?
DMI = 44.82 lb per day
Diet composition (DDGS contains
0.90% P, so diet will be 0.51% P)
Milk production = 65 lb per day
175 cows still
Class Exercise (Ruminants)
• Calculate P205 excretion for the example
CNMP dairy with 0.51% P in the diet
• Calculate the amount of land needed to
apply the P2O5 (assume 65 lbs of P2O5
needed for corn silage/acre) from the
manure from cows fed this new ration
(assume that only 50% of the time the
cows are in confinement)
Class Exercise (Answer)
Manure
P2O5
Produced
= (44.82 lbs. avg. feed intake (%dm) x 0.0051*) (65 lbs. avg. milk prod. per cow/day** x
0.001***) x 2.29****
= 0.1636 lbs. P per day per cow x 2.29
= 0..375 lbs. P2O5 per day per cow x 175 cows
x 365 days
= 23,953 lbs P2O5 per year
Acres
Required for P2O5 Mass
Balance
= 23,953 / 65 lbs. P2O5 removed by crop
= 368 acres X 50% confinement
= 184 acres
*0.51 % of P in total feed ration from feed analysis
**Based on 2000/2001 rolling herd average of 26700 lbs. of milk produced per
cow per year
***0.10 % of P in milk; ****conversion of P to P2O5
Class Exercise (Answer)
• Difference in P2O5 produced:
• 23,953 lbs – 14,094 lbs = 9,859 lbs more
produced; however, only 50%
confinement, so 4,930 lbs collected and
stored.
• Difference in acres of land required
(assuming 50% confinement):
• 184 acres – 108 acres = 76 acres more
needed
• If all the manure was collected (100%
confinement, then 151 acres more
needed
Computer Software Tools
• Dairy Whole Farm Balance Nutrition
Education Tool (WFBNET) –
www.puyallup.wsu.edu/joeharrison/soft
ware
• Whole Farm Balance – on CNMP Course
CD and at http://cnmp.unl.edu
• Nutrient and Land Estimator – on CNMP
Course CD and at http://cnmp.unl.edu