F. Toth 1, G. Gabor 1, Fan Huang 3 and R.G. Sasser 2, 3
1 Department of Cattle Breeding Research Institute for Animal Breeding, H-2053 Herceghalom, Hungary,
2 Department of Animal and Veterinary Science, University of Idaho, Moscow, ID, USA 83843 and
3 BioTracking LLC, 105 E. 2nd, Moscow, ID USA 83843

PREDICTION OF THE EMBRYONIC LOSS BY PREGNANCY-SPECIFIC PROTEIN B (PSPB) ELISA TEST IN DAIRY CATTLE

SUMMARY

Genetic selection programs have produced a modern dairy cow that is biologically efficient at producing large volumes of milk. Early embryonic loss is recognized as a major cause of reproductive wastage in these cows. PSPB is secreted into the blood of the pregnant female beginning early in pregnancy. This protein can be used for detection of pregnancy and trophoblastic function in ruminants. Field experiments were carried out on four dairy farms which had different levels of milk production (Farm I, 8000; Farm II, 9500; Farm III, 7500; and Farm IV, 7000 kg/cow/year). Early pregnancy detection was carried out between 30 and 36 days after AI using the BioPRYN ELISA test for PSPB. Sixty days followed AI, all pregnant animals were checked for pregnancy by rectal palpation. A total of 777 pregnancies were found. Determination of pregnancy was based on a calculated cutoff optical density (OD) in the ELISA test. When a sample OD was found above but close to the cutoff (within 20%), it was predicted that early embryo loss had occurred. Results of rectal palpations were accepted as the "true test value." One-hundred-nineteen embryonic losses were detected. These losses were divided into 2 groups depending on the time of the hypothetical loss. In Group 1, loss was predicted to have occurred (based upon OD value) between 25 and 36 days (n = 22; 2.9% of pregnancies) after AI. For Group 2, loss was predicted to have occurred between 36 and 60 days after AI and consisted of cows with embryo loss that were not predicted by the OD of the test; however, loss was evident from palpation at 60 days after AI. This non-predicted loss of 97 embryos occurred after the application of the ELISA. In Group 1, thirty-three embryonic losses were predicted by the ELISA and 66.7% of them were realized by 60 days after AI. Huge differences were found among the respective farms (4.2, 2.0, 1.1 and 4.3%) in Group I losses; while most were predictable, losses did not correlate (P > .05) with the milk production. Large differences also occurred among respective farms in Group II losses (1.1, 17.5, 8,6 and 10,6 %). These losses were correlated with the mean milk production of the farm (r = 0.9, P = 0.04). In conclusion, the BioPRYN ELISA test is a practical and safe system for pregnancy detection in cattle and can be used for prediction of the early embryonic loss from 25 to 36 days after AI.