Significant culling of high-producing cows with low fertility reduces profitability of dairy farms as those cows are replaced with heifers. Induced lactation of non pregnant cows may be a management alternative to increase profits. Adding replacement heifers to the milking string is one of the largest costsof dairy farming. There is potential to increase income by reducing the number of heifers raised or by selling excess heifers. An improved method to induce non pregnant cows into lactation could return to production valuable healthy cows that would otherwise be culled and at the same time decrease the need for replacement heifers.

1. Induced Lactation inNon pregnant Cows: Profitabilityand
Response to Bovine Somatotropin
By: Faisal A. Alshamiry
Supervisor Prof. Khaled Abdon
American Dairy Science Association
A. L. Magliaro, R. S. Kensinger, S. A. Ford, M. L. O’Connor, L. D. Muller, and R. Graboski
HORMONAL REGULATION IN THE FARM ANIMAL 631 (2)

2. INTRODUCTION
 Significant culling of high-producing cows with low fertility reduces profitability
of dairy farms as those cows are replaced with heifers.
 Induced lactation of non pregnant cows may be a management alternative
to increase profits.
 Adding replacement heifers to the milking string is one of the largest costs
of dairy farming.
 There is potential to increase income by reducing the number of heifers raised
or by selling excess heifers.
 An improved method to induce non pregnant cows into lactation could return to
production valuable healthy cows that would otherwise be culled and at the same
time decrease the need for replacement heifers.

3.  A role for prolactin in induced lactation is evident because induced cows treated
with reserpine to increase prolactin concentrations produced more milk than
controls.
 The present study is the first controlled study to compare milk production
responses to (bovine somatotropin) in cows hormonally induced into lactation.
 In order for induced lactation to be adopted as a management tool on dairy farms,
it must be economically viable.
 Under traditional management schemes, cows that fail to conceive are culled and
replaced with heifers.
 Reproductive problems account for 47% of the cows
culled from the dairy herd between the ages of 3 & 8 y.

4. The objectives
 Compare milk production responses to (bST) in cows
hormonally induced into lactation.
 Compare the profitability of induced cows to first-lactation
cows in the same herd.
OBJECTIVES OBJECTIVES OBJECTIVES OBJECTIVES OBJECTIVES
OBJECTIVES OBJECTIVES OBJECTIVES OBJECTIVES OBJECTIVES

5. MATERIALS AND METHODS

6. COWS (n = 28) were induced into lactation following
a dry period ≥50 DAY mean BW of 683 ± 68 kg
COWS (6) COWS (6) COWS (4) COWS (4) COWS (4) COWS (4)
Daily subcutaneous injections of
Estradiol-17β (0.075 mg/kg BW) + Progesterone (0.25 mg/kg BW)
for 1 - 7 day of the experiment.
Cows were housed in a climate-controlled barn in individual tie stalls
Milking began on 18 d of the experiment, and cows were milked once
per day until production reached approximately 4 kg.
Milking was twice daily until cows returned to the university herd at,
on average, 26 d of lactation.
Cows within each
group were paired
based on milk
production during
the first 20day
of induced lactation.
Within each pair,
cows were randomly
assigned to either
bST or control
treatment.
Each pair
commenced bST or
control treatment on
37 ± 20 day
of lactation.
After this 70 d bST/control treatment comparison, all induced cows received bST biweekly.
Daily milk yield and monthly milk composition were collected for the entire lactation.
From 1 to 5
previous lactations
Cows in the first 3 groups were
milked twice daily throughout
lactation
7
3
1 2
4
5
6
10
8
9
11
51mg+170mg

7.  Before initiation of lactation, cows were fed a (TMR) designed to meet the (NRC) requirements of late
gestation dairy cows (NRC, 1989).
 Beginning 2 d before milking commenced (treatment 16 day), cows received a mixture containing equal parts
of the dry cow (TMR) and a lactating cow (TMR).
 Once milking began, cows received the lactating cow (TMR) ad libitum.
 Cows continued to receive the same lactating cow (TMR) in free stall housing upon
their return to the university dairy herd.
 Ration compositions presented (Table 1) are representative of those fed over the course of this research.
 Because the experiment was conducted over several years, slight ration changes were inevitable.
FEEDING FEEDING FEEDING FEEDING FEEDING FEEDING FEEDING FEEDING

8.  Data were analyzed using the GLM procedure of SAS For the bST/control treatment comparison : Treatment,
Group, Cow (treatment × group), and Day. (Treatment × group) = error term.
 For the profitability analysis, 27 study cows were compared to peer first-lactation cows in the same herd.
The present values for each animal, j, were calculated using the following equation: PVj =Σi di
∗
(Mij + Fij + Pij − Cij − Hij − Aij + Rij − Sij)
Where, PVj = the present value of monthly net returns to animal j; di = the discount factor in month i; Mij = the base value of milk sold in month i from
animal j; Fij = the fat premium of the milk sold in month i from animal j; Pij = the protein premium of the milk sold in month i from animal j;
Cij = the feed cost for animal j in month i; Hij = the cost of bST and induced lactation treatment for animal j in month i; Aij = the cost of artificial
insemination services for animal j in month i; Rij = the value of animal j (or its replacement) at the termination of its participation in the trial in month I in
month i; Sij = the net replacement cost of animal j, if culled in month i.
Statistical analyses Statistical analyses Statistical analyses Statistical analys

9. Table 1. Diet composition and analyses for representative diets used.
Corn silage
Alfalfa hay, chopped
Grass hay, chopped
Grass hay silage
Alfalfa hay silage
Ground corn
Soybeans, cooked
corn
Canola meal
Wheat middlings
Barley
Dry cow grain mix
Dicalcium phosphate
Limestone
Vitamin/mineral mix
INGREDIENT,
% DM
DRY
COW
TMR
LACTATING
COW
TMR
34.9
—
19.9
19.7
—
5.9
—
—
8.4
—
—
10.5
—
0.15
—
28.6
8.9
—
4.2
8.4
16.5
5.0
7.5
10.1
3.7
3.7
—
0.08
1.16
2.2
LACTATING
COW
TMR
Composition
DRY
COW
TMR
DM, %
CP, %
ADF, %
NDF, %
CaDF, %
P, %
NEL, lactation, Mcal/kg DM
43.1
14.5
27.5
44.2
0.58
1.39
1.55
52.8
17.7
18.8
33.4
0.90
0.48
1.68
Table 2. Economic parameters used in the present value analysis.
Component Economic parameter
Milk price
Fat premium/discount (per 0.1% over/under 3.5%)
Protein premium/discount (per 0.1% over/under 3.2%)
Milk hauling
Induction treatment cost (materials only)
bST treatment cost
Daily feed cost
Value of cull animal
Value of milking animal
Discount factor
$0.297/kg
$0.0033/kg
$0.0055/kg
$0.013/kg
$10.58/cow
$6.07/injection
$3.93/animal
$500
$1200
6%

10. RESULTS & DISCUSSION

11. Figure 1. Comparison of milk yields of cows induced into lactation and
treated with bST with induced cows not treated with bST (control).
Cows treated with bST are represented by the solid diamond (◆) and
controls by the open square ( ). The 70-d bST treatment period began
on d 37  20 of lactation. Significant Treatment 
Time interaction, SE = 0.69, P < 0.01.
Table 3. Effect of bST on yield and composition of milk from cows
induced into lactation.
Component bST Control SE
Milk yield, kg/d
Fat, %
Protein, %
SCC, ×1000
28.4
3.78
3.28
275
24.1
3.82
3.40
408
0.69
0.13
0.06
158
0.01
N.S
N.S
N.S
P<
Table 4. Milk yield (12 month) and composition and DIM for cows
induced into lactation (n = 27) and peer first-lactation cows (n = 27).
Component
Induced
cows
Peer
first-lactation
cows
SE
Milk yield, kg
Fat, %
Fat yield, kg
Protein, %
Protein yield, kg
DIM
7405
3.85
277.5
3.48
253.2
286
8431
3.41
294.0
3.24
272.9
305
565.7
0.14
21.3
0.05
18.9
14
NS
0.05
NS
0.01
NS
NS
P<
A peer first-lactation cow was selected as a cohort for each induced cow based upon
first day of milking to balance for environmental effects.
Samples for milk composition were collected monthly for a 12-mo period.
The bST vs. control treatments were compared over a 70-d period beginning on d 37 ±
20 of lactation, with 14 cows per group. Milk production was measured daily and a
significant Treatment × Time interaction was observed. For analysis of milk
composition, 2 milk samples collected at 30-d intervals were used.
CONCLUSIONS

12. Table 5. Reproductive performance and outcomes of cows induced into
lactation and peer first-lactation cows (n = 27 in each).1
Component
Induced
cows
Peer
first-lactation
cows
SE
Culled during lactation
Low milk yield
Reproductive failure
Injury, health problem
Poor temperament
Poor udder type
Calved subsequently
Services/cow, all cows
Services/pregnancy,
pregnant cows
Interval between lactations,2 mo
6
3
3
-
-
-
21
1.6
1.6
12.5
P<
1A peer first-lactation cow was selected as a cohort for each induced cow based upon
first day of milking to balance for environmental effects.
2Interval between lactations is defined as the number of months between the first day
of milking in the present and subsequent lactations.
Table 6. Net present value, in dollars, of a 12-month stream of net incomes for
cows induced into lactation and peer first-lactation cows (n=27 in each).1
Net present value
Induced
cows
Peer
first-lactation
cows
SE
Actual
Milk prices 20% higher
Milk prices 20% lower
Replacement cost 20% higher
Replacement cost 20% lower
1966
2422
1509
2058
1873
1446
1933
956
1419
1473
145
177
113
152
138
0.05
0.07
0.01
0.01
0.06
P<
1 Data used in net present value analysis included milk price ($0.297/kg), fat premium or
discount per 0.1% over or under 3.5% ($0.0033/kg), protein premium or discount per
0.1% over or under 3.2% ($0.0055/kg), milk hauling charge ($0.013/kg), induction
treatment ($10.58/cow, materials only), bST treatment ($6.07/injection), daily feed
($3.93/animal), and values of calf ($100), cull animal ($500), and milking animal ($1200).
A discount factor of 6% was used. These values were chosen based upon current market
rates in Pennsylvania at the time of the study or were calculated based on cost of
materials and labor.
7
1
1
3
1
1
20
2.0
2.1
13.4
0.21
0.19
0.30
NS
NS
0.05

13. Cows hormonally induced into lactation with estrogen and progesterone produce
more milk in response to bST than non bST-treated controls.
Once lactation was established, the induced cows appeared normal in terms of
production, health, and behavior.
There was significant economic advantage to inducing non pregnant, healthy cows
into lactation rather than using replacement heifers.
If this technology is approved by the FDA, it could provide a management
alternative for dairy farmers to increase profitability.
CONCLUSIONS CONCLUSIONS CONCLUSIONS CONCLUSIONS CONCLUS