Uterine activity in cows during the oestrous cycle, after ovariectomy and following exogenous oestradiol and progesterone.
ABSTRACT Uterine activity was monitored in three, 2-year-old nulliparous Ayrshire heifers using intrauterine balloon-tipped catheters and pressure transducers during the oestrous cycle, after ovariectomy and following the intravenous infusion of progesterone and oestradiol-17 beta. During the oestrous cycle uterine activity, as measured by the frequency and amplitude of contractions, was greatest around oestrus and declined during the luteal phase of the cycle; there was a close correlation with peripheral progesterone concentrations. In two animals after bilateral ovariectomy spontaneous uterine activity persisted, whilst in the third animal the uterus was quiescent. In the first two heifers intravenous progesterone infusions reduced the spontaneous uterine activity, eventually completely abolishing it. There was evidence of a dose response effect at the two infusion rates. Oestradiol benzoate infusions initially inhibited spontaneous uterine activity before stimulating contractions with some evidence of a dose relationship. As demonstrated in normal cyclical and steroid-infused animals, uterine activity appears to be under the influence of both hormones although the influence of progesterone is greater.
- Theriogenology 01/1990; 34(6):1169-1184. DOI:10.1016/S0093-691X(05)80016-0 · 1.85 Impact Factor
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ABSTRACT: Prostaglandins are widely used in herd management due to their luteolytic properties. They have also a direct effect on the myometrium. We hypothesized, that dissimilar prostaglandin preparations would differ as to their contractile effect. Intrauterine pressure was recorded during the diestrus of lactating dairy cows using a transcervically placed intraluminal pressure microtransducer. After recording physiologic uterine motility for 30 min, prostaglandins (dinoprost, DL-cloprostenol, D-cloprostenol) or a placebo was administered intramuscularly, followed by a 2-h recording period. Significant differences were found for the area under the curve (P < or = 0.05) and mean amplitude (P < or = 0.05), whereas the number of spikes per 15 min and the baseline pressure during the last 3 min of every recording period did not differ significantly among treatments. Peak values for area under the curve and mean amplitude were found between 15 and 30 min after administration of DL-cloprostenol, while dinoprost yielded the steadiest plateau from this period until the end of the recording session. These results contrast with those of earlier studies comparing prostaglandins after intravenous administration.Theriogenology 08/1998; 50(3):445-55. DOI:10.1016/S0093-691X(98)00151-4 · 1.85 Impact Factor
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ABSTRACT: Inflammation of the reproductive tract of a cow occurs when the physical and functional barriers to contamination are breached or specific infection occurs. Commonly, contamination occurs at parturition and to a lesser extent at estrus. Uterine contamination following calving is common, but most healthy cows are able to clear the uterus of bacteria in the first 2 to 3 wk after calving. Persistent infections are more likely to be caused by Actinomyces pyogenes. Specific venereal infections tend to be more host-adapted and produce a lower grade inflammation. Nonspecific bacterial contamination of the endometrium generally induces a neutrophilic influx into the stratum compactum and uterine lumen. Neutrophils phagocytize bacteria with the aid of opsonins in the uterine fluid. Mast cells and eosinophils may also contribute to the inflammatory reaction, which may damage the surface epithelium and release vasoactive substances that allow leakage of serum antibodies into the uterine secretions. Specific antibodies of immunoglobulin (Ig) isotype A, M, G1, and G2 in uterine secretions have been described. In model species, the immune capability of the uterus is influenced by steroid hormones, especially estradiol, which increases secretory component and both IgA and IgG content in uterine secretions and increases the activity of antigen-presenting cells in the uterus. Similar cyclic fluctuations in immune components have been described for cows, including changes in the population of subsurface cytotoxic and helper T cells and changes in the expression of major histocompatibility II antigen on surface cells.Journal of Animal Science 02/1999; 77 Suppl 2:101-10. · 1.92 Impact Factor