Laboratoire d'Hormonologie, UNCEIA, Maisons-Alfort, France Pregnancy-Speci®c Protein B (bPSPB) and Progesterone Monitoring of Post-Partum Dairy Cows with Placental Retention M. TEFERA 1,4 , N. JEANGUYOT 2 , M. THIBIER 3 and P. HUMBLOT 2 Addresses of authors: 1 Department of Animal Science, Mekelle University, 231 Mekelle, Ethiopia; 2 Laboratoire d'Hormonologie, UNCEIA, 13 rue Jouet, 94703 Maisons-Alfort, France; 3 FAO, 52 Corso del Rinascimento 00186 Rome, Italy; 4 Corresponding author With 3 tables (Received for publication December 12, 1999) Summary The relationship between placental retention, progesterone and pregnancy-speci®c protein B (bPSPB) was determined in 60 calving Holstein cows. The cows were divided into two groups with placental retention (WPR, n  16) and no placental retention (NPR, n  44). Every 4 days, until 60 days post-partum, blood samples were taken and the uteri were checked using ultrasonography. The puerperal characteristics of NPR and WPR were as follows: mean days of abnormal vaginal discharge: 20.2  5 versus 35.6  7 (P < 0.01); mean intervals to uterine involution: 21.4  3.7 versus 27.6  7.6 days (P < 0.01); rate of endometritis: 25 versus 100 % (P < 0.01). The mean numbers of oestrus cycles per cow were 1.75  0.5 versus 0.85  0.9 (P < 0.05) and the mean durations of the ®rst oestrus cycle were 18  3.5 versus 16  2.1 days (P > 0.05). The mean intervals to ®rst ovulation were 21.5  8.4 versus 35  19 days (P < 0.01). bPSPB blood concentrations were higher in the WPR group at calving with 955  170 versus 750  205 ng/ml (P < 0.01) and also during the ®rst 32 days post-partum with 173.68  47.3 versus 131.0  29.2 ng/ml (P < 0.01). The mean bPSPB half-life was similar in the two groups: 6.9  2.5 versus 6.5  2.1 days (P > 0.05). In conclusion, it was found that placental retention was associated with a higher rate of endometritis, a lower number of cycles, longer interval to ®rst post- partum ovulation and higher concentration of bPSPB at calving and during the post-partum period. The positive relationship between bPSPB concentrations and calf birth weight and their association with post-partum pathological events may be useful in monitoring animals presenting high concentrations at calving. Introduction Parturition is a physiological process which marks the end of pregnancy, resulting in expulsion of the fetus and its enveloping membrane from the maternal organism. The post-partum period is a critical event in that a complete restoration of structural and physiological properties of the uterus is a prerequisite for successful fertilization and early embryonic development (Humblot, 1980). Bacteriological study of the post-partum uterus shows that contamination occurs at calving when the cervix is open, allowing the introduction of non-speci®c bacteria into the uterus (Noakes et al., 1991). Bacterial infection occurs in 90±100 % of cows during the ®rst 2 weeks post-partum, decreasing to 30 % in the ®fth week and to 9 % at 45±60 days post-partum (Grif®n et al., 1974; Hussain et al., 1990). Studies such as cytology (Chacin et al., 1990), histology (Chaffaux J. Vet. Med. A 48, 331±336 (2001) Ó 2001 Blackwell Wissenschafts-Verlag, Berlin ISSN 0931±184X U. S. Copyright Clearance Center Code Statement: 0931±184X/2001/4806±0331 $15.00/0 www.blackwell.de/synergy