Investigations into the mechanisms controlling parturition in cattle.

A pronounced increase in fetal cortisol concentrations stimulating an increase in estrogen production at the expense of progesterone precursors in the placenta, luteolysis, and progesterone withdrawal is considered as a key event during the complex signal cascade leading to the initiation of parturition in cattle. However, there are many questions concerning the exact functional and/or temporal relationships between these individual processes which finally result in the expulsion of the calf and the timely release of the placenta. Thus, parturition was induced in 270-day pregnant cows using the progesterone receptor blocker aglepristone (group AG, n=3), the prostaglandin F(2α) analog cloprostenol (group PG, n=4), and the glucocorticoid dexamethasone (group GC, n=4) to characterize the effect on maternal steroid and prostaglandin levels and to identify immediate subsequent changes in placental morphology and gene expression as compared with untreated controls sampled on day 272 (group D272, n=3) and cows during normal parturition (group NT, n=4).

Use of the progesterone (P4) receptor antagonist aglepristone to characterize the role of P4 withdrawal for parturition and placental release in cows.

In late pregnant cows, progesterone (P(4)) is mainly of luteal origin. However, the trophoblast may provide high local P(4) concentrations in the uterus. To test for the importance of a complete P(4) withdrawal for parturition-related processes and placental release, the P(4) receptor (PGR) blocker aglepristone (Ap) was administered to three cows on days 270 and 271 of pregnancy.

The assessment of carcass composition of Awassi male lambs by real-time ultrasound at two different live weights.

The accuracy of ultrasonography to measure fat thickness (FT) and longissimus dorsi muscle (LM) traits (area, depth and width) in live Awassi male lambs and predict carcass FT and LM traits was studied. Twenty six Awassi male lambs were randomly divided into light (L) (n=13) and heavy (H) (n=13) finishing lambs. Slaughter weight of lambs in L and H groups were 40 and 45kg, respectively.