Mm. Mialon et al., DETECTION OF PREGNANCY BY RADIOIMMUNOASSAY OF A PREGNANCY SERUM-PROTEIN (PSP60) IN CATTLE, Reproduction, nutrition, development, 34(1), 1994, pp. 65-72
The accuracy and efficiency of pregnancy diagnoses in cattle by pregna
ncy serum protein (PSP60) radioimmunoassay, a progesterone radioimmuno
assay or oestrus detection were compared. Blood samples were taken fro
m 349 suckling heifers and cows (1 191 inseminations) at 28, 35, 50 an
d 90 d post-insemination for PSP60 determination and at 22-23 d for pr
ogesterone. Females were declared nonpregnant when plasma PSP60 concen
tration was lower than 0.2 ng/ml at 28, 35 and 50 d and 0.5 ng/ml at 9
0 d. When compared with rectal palpation at 90 d, the accuracy of posi
tive (negative) diagnoses by progesterone assay was 80% (100%) in heif
ers and 75% (99%) in cows. The accuracy of positive diagnoses by PSP60
assay increased with gestation stage from 90% on d 28 in heifers (74%
in cows) to 100% (99% in cows) at the time of rectal palpation. This
accuracy was 84% on d 28 in cows when the interval from calving to blo
od sampling was higher than 115 d. Whatever the stage, the accuracy of
negative diagnoses was higher than 90%. Efficiency in detecting pregn
ant or nonpregnant females on d 28 was equivalent to the progesterone
assay. The method for detecting oestrus applied in this experiment was
as efficient as the PSP60 or progesterone test at any stage of gestat
ion. The PSP60 test is Very flexible, which makes its use particularly
interesting in naturally mated suckling herds because of the uncertai
nty regarding the date of fertilization.