Transcript 1. dia - Androvet Kft

Detection of the embryonic loss in dairy cattle by ELISA tests
György Gábor1* - Fruzsina Tóth1– László Ózsvári2– Garth Sasser3
1Research Institute
for Animal Breeding and Nutrition, Herceghalom, Hungary, 2Faculty of Veterinary Sciences, SZIE, Budapest,
Hungary, 3Biotracking LLC, Moscow, ID, US
Introduction
Improvement of reproductive management in the dairy industry is essential. The
continuous elevation of milk production is associated with a simultaneous dramatic
decrease of reproductive performance. Delayed post-partum interval, poor heat
expression, inefficient detection of estrus and fertilization failure are probably the
major causes of the reproductive wastage; but early embryonic death is recognized as
the major cause of reproductive wastage in cattle. The most common methods for early
pregnancy check /rectal palpation (35-42 days PI), B-mode ultrasonography (25-30
days PI) and examination of pregnancy specific proteins (PSPB, PAG, 29-30 days PI)/
are used for the decreasing of the calving interval in cattle. BioPrynTM (BioTracking
LLC, Moscow, ID, US), an ELISA test has been developed and is distributed for the
detection of PSPB in the circulation of pregnant cows. Pregnancy detection by
BioPrynTM is already routinely used in the author’s laboratory.
Objectives
The objective of this study was to develop a method for the recognition of embryonic
loss (EL) at the time early pregnancy detection (approximately 30-36 days post
insemination) by serum PSPB and serum P4 assays.
Material and Methods
Blood samples were assayed for the determination of the serum PSPB and P4
concentrations months at three Hungarian large scale dairy farms 30 to 36 days post
insemination. BioPryn was used for the early pregnancy detection (EPD) and retention
of pregnancy was determined by rectal palpation (RP) on Day 60 (day of AI=0). After
the early pregnancy diagnosis, open cows were immediately injected with either PGF2a
(presence of the corpus luteum, CL) or were put into an Ovsynch regimen (non-cycling
cows). Lower than expected optical density (OD) values for BioPRYN (+10 % of cutoff
OD) and the serum concentration of progesterone were used for prediction of embryonic
loss. If the OD value of a sample (PSPB) was ± 10 % to the cutoff OD for determining
pregnancy, the same sample was checked by a progesterone (P4) ELISA test
(QuantiCheck, Veterinorg Ltd., Budapest, Hungary). According to serum P4
concentration, cows were assigned to 3 categories: high (>4 ng/ml; maintenance of
pregnancy), medium (2-4 ng/ml; possible EL) and low (<2 ng/ml; EL) serum
progesterone (see Figure 1). Real embryonic losses were determined at the time of rectal
palpation (EPD – RP).
Figure 1: The prediction process for embryonic loss and for the
treatment methods of open cows and cows returning in estrus
Results
Pregnancies (n=1575) were detected from 3833 blood samples between 30-36 days post AI and 13.5 % of the pregnancy samples were tested by the P4 assay. A
total of 269 ELs were detected (17.1 %) after palpation on Day 60 and 50.9 % of them were predicted by ELISA at 30 to 36 days after AI. The rate of EL among
the progesterone categories were 83.8 % (low), 64.9 % (medium) and 37.5 % (high) respectively.
Farm
No. of pregnant
cows
No. of real
EL's
EL %
No. of non predicted EL
(NEL)
NEL %
No. of predicted EL
(PEL)
PEL %
1
634
115
18,1
51
44,3
64
55,7
2
591
117
19,8
65
55,6
52
44,4
3
350
37
10,6
16
43,2
21
56,8
Total
1575
269
17,1
132
49,1
137
50,9
Table 1: Number of predicted and non predicted embryonic loss by Biopryn
Farm
1
2
3
Total
Prediction %
Low
Predicted EL
33
19
16
68
83,8
True EL
27
19
11
57
Serum progesterone Level
Medium
Predicted EL
True EL
39
29
34
27
24
7
97
63
64,9
High
Predicted EL
17
14
17
48
37,5
True EL
8
6
4
18
Table 2: Efficiency of the EL prediction based on the serum P4 concentration
Discussion
It was found that the BioPRYN, with OD an indicator of PSPB level, and serum P4 concentration could identify EL. Lower PSPB serum level
significantly refers for LEL (p < 0.0001). Most of the cows with low serum PSPB level and have < 2 ng/ml serum P4 concentration lost the embryo
between the first and second pregnancy check (p < 0.0001). The most effective prediction rate was found in low P4 category (~ 90 %) while prediction
rate in the medium and high P4 category varied among the farms.
Conclusion
It can be concluded that BioPryn was useful for prediction of part of EL in dairy cows and that P4 concentration in these was related to rate of EL.
*email: [email protected]