the stochastic modeling to estimate the economic consequences of reproductive performance in dairy...
TRANSCRIPT
1
C. Inchaisri, H. Hogeveen,
R. Jorritsma, P.L.A.M., Vos,
G.C. van der Weijden
The stochastic modeling to estimate the
economic consequences of reproductive
performance in dairy cattle
Introduction
• Reproductive performance of individual cows is the
result of physiological interactions
• Many cow factors are involved
– Parity
– Milk production level
– Health
– Lactation stage
• The interactions are complex
• What are the economic consequences of these
interactions?2
Objectives
• To create a simulation model
1. To calculate the economic consequences for
reproductive performance of single cows – Average
– Good
– Poor
2. To calculate the economic benefits of improving
individual reproduction parameters.
3
4
Methodology
• Dynamic stochastic simulation model
– Monte Carlo
• One week of time step
• The relations of cow factors were adjusted
– Literature
– Authors’ expertise
5
Dynamics of the model
Cow
Milk production
1st Ovulation
Ovulation
summarize
DisorderEstrous
Detection
AI
Conception
yes
yes
yes
yes
no
no
no
no
yes
Milk production
• Wood’s Function
• Depending on
– Parity, milk declining rate, milk production loss due
to gestation
• Base values
– Norm (8310 10%) kg/305 days
– 6 wks at peak
7
8
The first ovulation
• 1st Ovulation time (wks)
• Depending on parity
– Primiparous cows
= Lognorm(5.36, 5.04, Truncate(1, 10))
– Multiparous cows
= Lognorm(4.53, 3.08, Truncate(1, 10))
Cow
Milk production
1st Ovulation
Ovulation
Estrous
Detection
AI
Conception
yes
yes
yes
yes
no
no
no
no
10
Cow
Milk production
1st Ovulation
Disorder
Ovulation
summarize
Estrous
Detection
AI
Conception
yes
yes
yes
yes
no
no
no
no
yes
Culling, if not pregnant
40 wks pp.
Reproductive cycle 1
• Ovulation
– At least 3 weeks interval
• Estrous detection
– Milk production
– Days in milk
11
Reproductive cycle 2
• Insemination
– Voluntary waiting period (VWP)
• Conception
– Parity
– Milk production
– Days in milk
12
Internal validation
• Input, processing and output
• The rationalism method
• Face validity
Economic calculation
Excellent & Realistic scenarios
14
Annual Economic losses
Revenue
and Cost
Net
Economic
Losses
A partial
budget
approach
Milk(kg)/cow/yr
Calves/cow/yr
No. Services
Culled cow
Calving
management
Input of excellent scenario
Reproductive performances Excellent
The ovulations rate after the 1st ovulation 1.00
Estrus detection rate 1.00
Conception rate 1.00
Incidence rate of disorders 0
Voluntary waiting period (wks) 6
Input of realistic scenarios
Reproductive performances Good Average Poor
The ovulations rate after the 1st ovulation 1.00 0.95 0.90
Estrus detection rate 0.70 0.50 0.30
Conception rate 0.70 0.50 0.30
Incidence rate of disorders 0.03 0.07 0.11
Voluntary waiting period (wks) 9 12 15
Results and conclusion
18
0
10
20
30
40
50
60
70
80
90
0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 9501000
Per
cen
t o
f co
ws
Annual net economic losses (€/cow)
Distribution of economic losses
per cow per year
Good
Average
Poor
Mean net losses per cow per year
19
0 € 28
€ 88
€ 282
0
50
100
150
200
250
300
Excellent Good Average Poor
Economic losses Good Average Poor
Milk production 26 72 128
Calf 11 21 30
Culling 0 14 187
AI 3 8 12
Calving management -13 -25 -35
21
Sensitivity analysis
0.90
1.00
0.30
0.70
0.30
0.70
0.11
0.30
15 wks
9 wks
2.32
-1.04
74.95
-22.83
95.30
-33.40
0.67
-0.49
20.82
-16.86
-50 -30 -10 10 30 50 70 90 110
Ovulation
Estrous detection
Conception
Incidence rate
Voluntary waiting period
• Main causes
– Decreased milk production
– Increased culling rate (poor fertility)
• The conception rate, estrous detection rate
and VWP have the large effect on economic
• These losses could vary largely between
cows
• Next steps
– Which combination of cow factors is responsible
for the high and low economic outcomes ???
24