Download Chapter 5

‫فصل پنجم‬
‫عوامل موثربرتوليد و تركيب شير‬
‫خصوصيات يك گاو شيرده پرتوليد چيست؟‬
365 day lactation
Milk 57,460 lb
Fat 4.0% (2,318 lb)
Protein 3.5% (2,020 lb)
Ruann Royalty Cora 1994
Beecher Arlinda Ellen 1975
70
Milk
Maintenance
NEL intake, Mcal/d
60
50
40
83%
30
75%
75%
20
66%
&5%
75%
10
0
Av. US cow
27 kg
Cora
72 kg
Holstein
45 kg
Jersey
24 kg
70
Milk
Maintenance
NEL intake, Mcal/d
60
50
40
83%
30
75%
20
66%
&5%
75%
10
0
Av. US cow
27 kg
Cora
72 kg
Holstein
45 kg
Jersey
24 kg
70
Milk
Maintenance
NEL intake, Mcal/d
60
50
40
83%
30
75%
20
66%
85%
10
0
Av. US cow
27 kg
Cora
72 kg
Holstein
45 kg
Jersey
24 kg
‫عوامل موثر بر توليد و تركيب شير‬
‫عوامل موثر بر توليد وتركيب شير‬
Daily yield and composition of milk
are affected by :
1-Physiological
2- Environmental

‫عوامل موثر بر توليد وتركيب شير‬
Physiological factors are divided into two
parts:
1- Inheritance
2- Nonhereditary factors such as age, No.
of previous lactations and pregnancy
‫نوسان روز تا روز‬



Both milk yield and percentage
composition of milk vary considerably
from day to day.
Daily variation in milk yield is related to
the completeness of evacuation of milk
from the udder.
Variation caused by disease, undernutrition, cows being off-feed, and related
factors are usually of longer duration than
those caused by udder evacuation,
incomplete milking, estrus, or excitement.
‫منحني نورمال شيردهي‬

The relationship between milk yield to
the milk fat and protein percentage is
negative (Fig 1).
Phase 4
Peak Milk
Phase 5
Peak DMI
Phase 6
Tail End
Phase 1
Phase 3
Dry
Matter
Intake
Cl
Fa ose
rO
Up
ff
Phase 2
Fresh
Milk
Production
Body Weight
0
1
2
3
4
5
6
7
Month
8
9
10 11 12
Period of Negative
Energy Balance
ht
g
i
e
W
y
Bod
Dry M
atte r
Intak
e
M il
k Pr
odu
ctio
n
Lactation
DMI and Milk Production During
Early Lactation
60
50
kg/d
40
30
20
Milk yield
10
Dry matter i ntake
0
-4
-3
-2
-1
1
2
3
4
5
6
7
8
9
10 11 12 13
Week of Lactation
McGuire, unpublished
Energy Balance of 29 ID Cows During
Early Lactation
15
10
5
0
-5
-10
-4 -3 -2 -1 1 2 3 4 5 6 7 8 9 10
Week of Lactation
Energy Balance versus Body Condition
Score
15
10
BCS
3.5
5
3
0
BCS
EB
2.5
-5
-10
2
Energy balance
(Mcal/d)
4
-15
12
11
10
9
8
7
6
5
4
3
2
1
-1
-2
-3
-4
Week of lactation
McGuire, unpublished
? Which Cow is Thin
BCS = 1.0
3.5
Which Cow is in Negative
Energy Balance ?
5.0
Stage of Lactation & Parity
(Milk Yield – lbs./day)
Parity > 1
100
Parity = 1
80
60
40
20
0
1
2
3
4
5
6
7
Months post-partum
8
9
10
Peak Milk

40 to 70 days postpartum

Second month on DHI test

Peak times 200 equals lactation total
potential


Example: 45 kg X 200 = 9000 kg
Heifers (1st Lactation) equal 75% of older
cow peaks (2nd + Lactation)

Example: 66 kg / 85 kg = 77.6%
:‫اوج توليد بستگي به عوامل زير دارد‬




Body condition
Inherited potential
Freedom from metabolic and infectious
diseases
Feeding regime
Persistency: Is the rate of
decline in yield after calving
‫تداوم در شيردهي‪ :‬نرخ يا ميزان كاهش در‬
‫توليد بعد از زايمان‬
‫آغوز‬
The first milk after parturition is colostrum,
which has a marked difference from that
of normal milk (Table 1).
‫عوامل محيطي‬
‫رطوبت ودرجه حرارت‬


Temperatures between 4-24 o C have
no effect on the milk production of most
dairy cows.
In this range known as the comfort
zone, no body processes are directly
involved inn maintaining body
temperature (Fig 5).
Temperature & Humidity
(Percentage of max.)
-17
-7
4
15
Temperature, C
27
38
48
Lower Critical
Temperature
Maintenance
Cold
Thermal Comfort Zone
Kilocalories
Gain
Upper Critical
Temperature
Effective Temperature
Intake
Heat
22
0
20
Relative Humidity, %
60
40
80
Degrees, C
NO
27 STRESS
32
MILD
STRESS
HEAT
STRESS
38
43
49
SEVERE
STRESS
DEAD
COWS
100
Gestation



The exact reason for the decrease in
milk production at the end of the
pregnancy is not known.
One hypothesis is an increase in the
nutrient required for fetal development.
A more reasonable explanation is a
hormonal changes that occur at this
time.
Pregnancy Status
(Milk Yield – lbs./day)
100
Open
80
60
Conception
40
Pregnant
20
0
1
2
3
4
5
6
7
Months post-partum
8
9
10
A. Pezeshki,* J. Mehrzad,† G. R. Ghorbani,‡ H. R.
Rahmani,‡ R. J. Collier,§ and C. Burvenich*1
J. Dairy Sci. 90:5531–5541
Journal of Dairy Science Vol. 90 No. 12, 2007
Previous Days Dry (Lactation
Yield as a Percentage of max.)
105
100
95
90
85
80
75
0
20
40
60
80
Previous Days Dry
100
120
Previous Days Open (Lactation
Yield as a Percentage of max.)
20
40
60
80
100
120
Previous Days Open
140
Month of Calving
(Percentage of max.)
D B E F O
K T M S M A A
Month of Calving
Current Days Open (Lactation
Yield as a Percentage of max.)
20
40
60
80
100 120 140 160
Current Days Open
Body Weight


General relationship exist between the
BW of the cows and the amount of milk
produced.
Larger cows have more udder secretory
tissue and larger digestive systems.
Photoperiod

Cows subjected to 16 h of light and 8 h
of darkness produced 7-10% more milk
than those exposed to 9-12 h of light
per day.
Factors Affecting Milk Yield
and Composition



Disease
 Mastitis
 Metabolic disease
 Locomotive disease
 Displaced abomasum
 Calving problems (dystocia)
Bovine somatotropin (bST)
Oxytocin