117 THE OVARY ACTIVITY IN COWS WITH AND WITHOUT RETAINED FETAL MEMBRANES Santa Skuja , Vita Antāne LLU Veterinārmedicīnas fakultāte, Latvija LUA, Faculty of Veterinary Medicine, Latvia santa.skuja@ inbox.lv , vita.antane@llu,lv ABSTRACT The aim of the study was to find out the ovary activity in cattle with and without retained fetal membranes. Sixty cows of different age of Latvian black-and-white breed from two Joint Stock Companies were used in the present research. The animals were divided into two groups: control group (cows without retained fetal membranes - NRFM) of 15 cows and 45 cows with retained fetal membranes (RFM). Research was performed from September 2007 to January 2009. The level of progesterone in blood serum and rectal ultrasonography were used to establish the ovary activity in cows. The serum progesterone concentration was analyzed every two days for six weeks. The mean serum progesterone concentration during the first 14 days postpartum (PP) in cows with and without RFM was under 1ng/ml. Subsequently (day 18 to 32), progesterone concentration in cows with RFM increased from 1.24 ± 0.14ng/ml to 6.43 ± 0,76ng/ml but in NRFM (day 18 to30) the progesterone increased from 0.74 ± 0.11ng/ml to 3.40 ± 1. 15ng/ml. On day 42 PP, the progesterone level was decreased in both groups of cows: in RFM group to 3.34 ± 0.32 ng/ml, in the NRFM group to 1.97 ± 0.68 ng/ml (P<0.05). When analysing the progesterone concentration in blood in individual animals during six weeks PP, it was found out that progesterone level was constantly low (<1ng/ml) in 32% of RFM cows and 20% of NRFM cows. The obtained results with ultrasonograph confirmed the ovary functional condition that was established according to the changes of the progesterone concentration in blood. It was concluded that in cows with retained fetal membranes the progesterone level postpartum was higher and decreased later in comparison with control group cows that could be the reason for a delayed folliculogenesis and ovulation. KEY WORDS: ovary, cows, ultrasonography, progesterone, retained fetal membrane. INTRODUCTION During the postpartum period, the uterus involution takes place and the ovary activity is renewed. Ten days postpartum, an antral follicle is found in ovaries indicating the beginning of a new follicular phase. In this time, the progesterone level in blood is low. In milking cows, the ovary activity and the increase of progesterone level in blood start a new in 18-25 days post partum (Senger, 2005). In cows with retained fetal membranes and without retained fetal membranes the mean progesterone level just postpartum is similar and below 1ng/ml (Bosu et al., 1984; Chew et al., 1977). Two days later it increases and in cows with RFM reaches 3.4 ± 0.3 ng/ml, and in cows without RFM 2.3 ± 0.1 ng/ml (Chew et al., 1977). Kaczmarawski et al. (2006) reported, that in cows with RFM the progesterone concentration in blood 12- 24 h postpartum is significantly higher (2,61 mmol/l) than in NRFM cows (1,59 mmol/l), and in cows with developed metritis the progesterone concentration decreases slower. Holt et al. (2010) has found the corpus luteum in the ovaries of cows with RFM