Table 1.
Comparison of RTU (3.5 or 5.0 MHz sector or linear probes)
at d 18 to
20, 21 and 24 in diagnosing pregnancy in swine (NC State Trials).
|
Item
|
RTU
(Part 1, Tech. A) |
RTU
(Part 2) |
|||||
|
3.5 MHz (sector) |
5 MHz (sector) |
3.5 &
5 MHz (sector) |
5 MHz
(linear) d 21 |
3.5 MHz
(sector) Tech B |
|||
|
d 21 |
d 21 |
d 18-20 |
Tech A |
Tech B |
d 21 |
d 24 |
|
|
False Open, % Diagnosed open but actual status pregnant |
8.2 |
2.05 |
26.9 |
1.7 |
4.4 |
16.0 |
0.0 |
|
False Pregnant, % Diagnosed pregnant but actual status open |
2.0 |
2.05 |
21.1 |
3.4 |
7.4 |
6.0 |
2.1 |
|
True Open, % Diagnosed open and actual status open |
44.9 |
44.9 |
22.5 |
34.5 |
43.4 |
44.0 |
45.8 |
|
True Pregnant, % Diagnosed pregnant and actual status pregnant |
44.9 |
51.0 |
29.5 |
60.4 |
44.8 |
34.0 |
52.1 |
|
Sensitivity, Ability to detect pregnant sows; % of pregnant
sows diagnosed pregnant |
84.6 |
96.1 |
65.6 |
97.3 |
91.1 |
68.0 |
95.6 |
|
Specificity, Ability to detect open sows; % of open sows
diagnosed open |
95.7 |
94.7 |
56.9 |
91.0 |
85.4 |
88.0 |
100.0 |
|
Accuracy, Ability to detect pregnant and open sows |
89.8 |
95.9 |
61.4 |
94.9 |
88.2 |
78.0 |
97.9 |
Table 2. Efficacy of RTU (5.0 MHz sector probe)
in
diagnosing pregnancy in swine (initial field trial).
|
Item
|
RTU
|
||||
|
17-20 |
21-23 |
24-30 |
38-44 |
52-58 |
|
|
False Open, % Diagnosed open but actual status pregnant |
18.2 |
0.0 |
0.4 |
0.0 |
0.0 |
|
False Pregnant, % Diagnosed pregnant but actual status open |
7.3 |
3.0 |
1.8 |
1.9 |
1.3 |
|
True Open, % Diagnosed open and actual status open |
7.3 |
4.2 |
4.2 |
1.5 |
0.8 |
|
True Pregnant, % Diagnosed pregnant and actual status pregnant |
67.2 |
92.8 |
93.6 |
96.5 |
97.9 |
|
Sensitivity, Ability to detect pregnant sows; % of pregnant
sows diagnosed pregnant |
78.7 |
100.0 |
99.6 |
100.0 |
100.0 |
|
Specificity, Ability to detect open sows; % of open sows
diagnosed open |
50.0 |
58.3 |
70.0 |
44.1 |
36.4 |
|
Accuracy, Ability to detect pregnant and open sows |
74.5 |
97.0 |
97.8 |
98.0 |
98.7 |
Table 3. Comparison of RTU (5 MHz linear probe)
versus A-mode in diagnosing
pregnancy in swine (Trial 1).
Item
|
A-mode, d 28 |
RTU, d 21 |
|
False Open, % Diagnosed open but actual status pregnant |
6.5 |
2.6 |
|
False Pregnant, % Diagnosed pregnant but actual status open |
0.1 |
13.8 |
|
True Open, % Diagnosed open and actual status open |
1.9 |
2.0 |
|
True Pregnant, % Diagnosed pregnant and actual status pregnant |
90.7 |
81.6 |
|
Sensitivity, Ability to detect pregnant sows; % of pregnant
sows diagnosed pregnant |
97.2 |
96.9 |
|
Specificity, Ability to detect open sows; % of open sows
diagnosed open |
66.7 |
12.7 |
|
Accuracy, Ability to detect pregnant and open sows |
92.6 |
83.6 |
Table 4.
Reproductive status of sows diagnosed
for pregnancy using RTU (5 MHz
linear probe) or A-mode (Trial 2).
|
Result (n / percentage) |
A-mode |
RTU |
|
Abortion |
22 / 1.5 |
14 / 0.9 |
|
Farrow |
1235 /
85.9 |
1329 /
84.9 |
|
Irregular Return |
38 / 2.7 |
50 / 3.2 |
|
Regular Return |
116 /
8.1 |
130 /
8.3 |
|
Removed |
22 / 1.5 |
36 / 2.3 |
|
Other |
4 / 0.3 |
7 / 0.4 |
Total |
1437 |
1566 |
Table 5.
Comparison of RTU (5 MHz linear probe)
versus A-mode in diagnosing
pregnancy in swine (Trial 2).
|
Item |
A-mode |
RTU |
||
|
d 28 |
d 35 |
d 21 |
d 28 |
|
|
False Open, % Diagnosed open but actual status pregnant |
0.4 |
0.4 |
2.4 |
0.1 |
|
False Pregnant, % Diagnosed pregnant but actual status open |
6.1 |
5.8 |
5.9 |
6.0 |
|
True Open, % Diagnosed open and actual status open |
0.7 |
0.5 |
4.0 |
2.3 |
|
True Pregnant, % Diagnosed pregnant and actual status pregnant |
92.8 |
93.3 |
87.8 |
91.7 |
|
Sensitivity, Ability to detect pregnant sows; % of pregnant
sows diagnosed pregnant |
99.6 |
99.6 |
97.4 |
99.8 |
|
Specificity, Ability to detect open sows; % of open sows
diagnosed open |
10.9 |
7.2 |
40.4 |
27.5 |
|
Accuracy, Ability to detect pregnant and open sows |
93.6 |
93.8 |
91.8 |
93.9 |
Table 6.
Additional costs of real-time ultrasound
versus the number of sows
tested per week.
|
No Sows Tested/ Machine/Week |
Total Sows |
|
Additional Cost(3 year life) |
|
Additional Cost (5 year life) |
||
|
($/Sow Tested) |
($/Year) |
($/Sow Tested) |
($/Year) |
||||
|
25 |
500 |
|
$2.214 |
$2,878 |
|
$1.521 |
$1,977 |
|
50 |
1,000 |
|
$1.072 |
$2,787 |
|
$0.725 |
$1,886 |
|
100 |
2,000 |
|
$0.501 |
$2,605 |
|
$0.328 |
$1,704 |
|
200 |
4,000 |
|
$0.215 |
$2,241 |
|
$0.129 |
$1,340 |
|
300 |
6,000 |
|
$0.120 |
$1,877 |
|
$0.063 |
$976 |
|
400 |
8,000 |
|
$0.073 |
$1,513 |
|
$0.029 |
$612 |
|
500 |
10,000 |
|
$0.044 |
$1,149 |
|
$0.010 |
$248 |
|
600 |
12,000 |
|
$0.025 |
$785 |
|
$(0.004) |
$(116) |
|
700 |
14,000 |
|
$0.012 |
$421 |
|
$(0.013) |
$(480) |
|
800 |
18,000 |
|
$0.001 |
$57 |
|
$(0.020) |
$(844) |
|
Values adjusted for labor savings associated with RTU vs.
A-mode (two vs. one check). |
|||||||
Table 7. Effect of
number of sows and percentage improvement
above A-mode in detecting open sows
(False Pregnant) on open sow days.
|
Number of Sows |
%
Improvement in Detecting Open Females |
|||||
|
0.1 |
0.5 |
1.0 |
2.0 |
3.0 |
4.0 |
|
|
1 |
0.5 |
0.8 |
1.1 |
1.8 |
2.6 |
3.3 |
|
500 |
255 |
396 |
572 |
924 |
1,277 |
1,629 |
|
1,000 |
510 |
792 |
1,144 |
1,849 |
2,553 |
3,258 |
|
2,000 |
1,020 |
1,583 |
2,288 |
3,697 |
5,106 |
6,516 |
|
4,000 |
2,039 |
3,167 |
4,576 |
7,394 |
10,213 |
13,031 |
|
6,000 |
3,059 |
4,750 |
6,864 |
11,092 |
15,319 |
19,547 |
|
8,000 |
4,079 |
6,334 |
9,152 |
14,789 |
20,426 |
26,062 |
|
10,000 |
5,099 |
7,917 |
11,440 |
18,486 |
25,532 |
32,578 |
|
Values adjusted for additional cost of RTU. Assumptions:
CR = 85%; earliest day scanned = 23. |
||||||
Table 8.
Relationship between conception rate and percentage
improvement of
real-time ultrasound above A-mode in detecting open
sows (specificity) on
number of open sow days saved by real-time ultrasound.
|
% Improvement |
Number
of Open Sow Days Saved (Standard Culling) |
||||
|
70% |
75% |
80% |
85% |
90% |
|
|
0 |
0.392 |
0.265 |
0.162 |
0.085 |
0.032 |
|
0.10 |
0.419 |
0.292 |
0.189 |
0.112 |
0.059 |
|
0.50 |
0.528 |
0.400 |
0.298 |
0.220 |
0.168 |
|
1.00 |
0.663 |
0.536 |
0.433 |
0.356 |
0.303 |
|
2.00 |
0.934 |
0.807 |
0.704 |
0.627 |
0.574 |
|
3.00 |
1.205 |
1.078 |
0.975 |
0.898 |
0.845 |
|
4.00 |
1.476 |
1.349 |
1.246 |
1.169 |
1.116 |
|
5.00 |
1.747 |
1.630 |
1.517 |
1.440 |
1.387 |
|
6.00 |
2.018 |
1.891 |
1.788 |
1.711 |
1.658 |
|
Standard culling assumes that sows are culled the second
time they are detected open. RTU initiated at 28 d gestation. |
|||||
Table 9. Number of
open sow days saved as
affected by number of sows and day RTU is initiated.
|
Number of Sows |
Earliest
Day RTU Scanning Initiated |
|||||
|
21 |
23 |
25 |
27 |
29 |
31 |
|
|
500 |
614 |
570 |
526 |
482 |
438 |
394 |
|
1,000 |
1,231 |
1,143 |
1,055 |
967 |
879 |
791 |
|
2,000 |
2,463 |
2,287 |
2,112 |
1,936 |
1,760 |
1,584 |
|
4,000 |
4,927 |
4,576 |
4,224 |
3,873 |
3,521 |
3,170 |
|
6,000 |
7,391 |
6,864 |
6,337 |
5,809 |
5,282 |
4,755 |
|
8,000 |
9,855 |
9,152 |
8,449 |
7,746 |
7,043 |
6,340 |
|
10,000 |
12,319 |
11,440 |
10,561 |
9,682 |
8,804 |
7,925 |
|
Assumptions: % improvement above A-mode = 1.0; Farrowing
rate = 85% |
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