Assessment of Progesterone Concentration Using Enzymeimmunoassay, for Early Pregnancy Diagnosis in Sheep and Goats

Abstract

The objective of this study was to determine a value of serum progesterone (P4) concentration, assessed using an enzymeimmunoassay (EIA), for the early distinction between pregnant and non-pregnant ewes and goats. Adult, non-lactating ewes of Chios (n=53), Berrichon (n=30) and Sfakia (n=45) breeds were synchronized during the breeding season with progestagens and gonadotrophins and mated to fertile rams (Experiment I). Adult, lactating goats of Swiss breeds (Alpine and Saanen, n=104) and indigenous Greek breed (n=45) were synchronized during the transitional season with progestagens, PGF2alpha and gonadotrophins. Cervical artificial insemination (AI) with fresh semen was applied once, 42-44 h after sponge removal (Experiment II). Jugular blood samples were collected on day 19 after sponge removal (ewes) or on day 21 after AI (goats) and serum P4 concentration was determined by EIA. Progesterone concentrations >/=1.0, >/=1.5, >/=2.5 and >/=4.0 ng/ml were tested as indicative of pregnancy. Pregnancy diagnosis was verified on birth. In the case of sheep, using a discriminatory level of 2.5 ng/ml, overall accuracy of pregnancy diagnosis was 91.4% and predictive value of negative and positive diagnoses were 98.3 and 85.3%, respectively. In the case of goats, predictive value of negative diagnosis was 95.8 and 94.0% and predictive value of positive diagnosis 71.3 and 71.7%, for 1.5 and 2.5 ng/ml, respectively; overall accuracy was 79.2% using either level. The other discriminatory levels tested did not improve these results. A significant positive correlation was observed between P4 concentration and the number of lambs or kids born, and further analysis indicated that this relationship is not a simple linear function. Based on the results of this study, P4 concentrations of 2.5 ng/ml in the case of ewes and 1.5-2.5 ng/ml in the case of goats, determined with EIA, are proposed as discriminatory levels between pregnant and non-pregnant animals, at an interval of one oestrous cycle after service.

Pregnancy diagnosis techniques in goats – a review

“…Various methods are used for analysis of blood, milk and faecal progesterone concentrations in small ruminants for evaluation of their endocrine status -immunoenzymatic (ELISA), radioimmune (RIA) and immunochemiluminescence analysis (Boscos et al, 2003;Gaafar et al, 2005;Capezzuto et al, 2009;Jack et al, 2012).…”

“…The analysis of blood plasma or serum progesterone is indicative for pregnancy after post insemination day 21 (Boscos et al, 2003;Medan et al, 2004;Capezzuto et al, 2009). Blood plasma concentrations >1 ng/mL between days 15-17 for nulliparous and days 18-22 in parous goats indicate pregnancy.…”

“…Blood plasma concentrations >1 ng/mL between days 15-17 for nulliparous and days 18-22 in parous goats indicate pregnancy. The accuracy of the assay is 75-86% in pregnant and 90-100% in non-pregnant goats (Dawson, 1999;Boscos et al, 2003;Khadiga et al, 2005).…”

ANTIBODY POLYCLONAL PRODUCTION ON RABBIT ANTI-OVINE PREGNANCY-ASSOCIATED GLYCOPROTEIN (Rabbit anti-ovPAG)

“…Pregnancy-associated glycoprotein could be detected in blood using radioimmuno assay (RIA) at the attachment of placenta during development of fetomaternal sincysium ( Ranilla et al, 1994;Verberckmoes et al, 2004). Of this, PAG could be used as pregnancy indicator and also feto-placental wellbeing (Karen et al, 2003;Boscos et al, 2003).…”

Changes in Fecal Progestagen Profile After Excretion in Miniature Pigs

“…o monitor ovarian function in animals, the progesterone concentration is usually measured using plasma and serum [1][2][3]; however, blood sampling entails retraining the animal and insertion of a needle into it, both of which induce stress. These stressors possibly interfere with the precise timing of reproductive hormone release within the follicular phase and possibly reduce the productivity of animals [4].…”