Collagen and Microvascularization in Placentas From Young and Older Mares.

In older mares, increasing collagen fibers (fibrosis) in the endometrium and oviduct predisposes to sub-fertility and infertility. In this study, (i) gene transcription of collagen (qPCR: COL1A1, COL1A2, COL3A1, COL5A1); (ii) total collagen protein (hydroxyproline); (iii) collagen distribution (Picrosirius red staining; polarized light microscopy); and (iv) microvascular density (Periodic acid-Schiff staining), were evaluated in mares' placenta, and related to mares age, and placenta and neonate weights. Samples were collected from the gravid horn, non-gravid horn, and body of the placenta from younger (n = 7), and older mares (n = 9) of different breeds. Transcripts of COL1A1, COL3A1 and COL5A1, total collagen protein, chorionic plate connective tissue thickness, and microvascularization increased in the gravid horn of older mares' placentas, compared to the youngest (P < 0.05). Although in other species placenta fibrosis may indicate placental insufficiency and reduced neonate weight, this was not observed here. It appears that older fertile mares, with more parities, may develop a heavier, more vascularized functional placenta with more collagen, throughout a longer gestation, which enables the delivery of heavier foals. Thus, these features might represent morphological and physiological adaptations of older fertile mares' placentas to provide the appropriate nutrition to the equine fetus.

Preliminary results on the association with feeding and recovery length in equine colic patients after laparotomy.

Colic is a serious disease for horses and the nutritional management of postoperative colic patients is an extremely important field. The aim of this retrospective study was to analyse the different factors, especially related to nutritional management, that may be associated with recovery length during hospitalization after a surgical intervention for colic, using a multivariate model. Data were collected from the records of horses presented to two hospitals and undergoing surgery for colic. The length (days) of recovery was the outcome of interest and was taken into account as a reference parameter (short, medium, long). The parameters collected (patient details, preoperative clinical and laboratory examinations, postoperative parameters and post-surgery nutritional parameters) were subjected to multivariate analysis (MCA and PCoA). A ranking class dataset was used to calculate Kendall's tau correlation of the length of recovery with respect to other parameters. Descriptive statistic to identify differences in the recovery length among groups (Kruskal-Wallis and Dunn's Multiple Comparison Test) was also performed. p value was set at < 0.05. Groups were not different in preoperative clinical parameters (BCS, PCV, total protein), postoperative parameters (time to 1st defecation, time to the end of IV fluid therapy and time to first water drinking, anaesthesia) and patient details (age). The comparison among groups revealed differences on the post-surgical nutritional parameters. Horses with short recovery consumed higher % of DM as forages in the 24 hr compared with the horses that have a long recovery and reach the minimum DM intake in a shorter period. Both Kendall and MCA analysis confirmed that the time to first feeding had a positive association with the length of recovery. Only 37 horses undergoing colic surgery were included in the study. From a clinical standpoint, this study has shown which nutritional parameters are associated with short recovery.

The Effect of Coumestrol on Progesterone and Prostaglandin Production in the Mare: In Vitro and In Vivo Studies.

Coumestrol (Cou) is a plant-derived phytoestrogen that induces various pathologies in the female reproductive tract. Although effects of phytoestrogens on reproductive function in other species are well documented, their influence on progesterone (P4) and prostaglandin (PG) secretion in the mare is unknown. The aim of this study was to determine if Cou directly affects P4 and PG concentrations (in vivo) and endometrial PG secretion (in vitro) in the mare. In experiment 1, the mares (n = 4) were fed for 14 days on a diet containing increasing proportions of alfalfa pellets (250 g-1 kg/day). An additional 4 mares were fed a standard diet (control group). Sequential blood samples were obtained for 8 h after feeding on Days 13 and 14 (1 kg/day alfalfa pellets). Feeding the mares alfalfa pellets up-regulated PGE2 and 13,14-dihydro-15-ketoprostaglandin F2alpha (PGFM) and down-regulated P4 in the blood plasma compared to those in the control group (P < 0.05). In experiment 2, epithelial and stromal cells were exposed to E2 (10-9 M) or Cou (10-8 M) for 24 h. In the in vitro study, Cou increased PG secretion in epithelial and stromal cells (P < 0.05). In both types of endometrial cells, Cou up-regulated PTGS-2 protein expression (P < 0.05). Moreover, PGES and PGFS proteins were up-regulated by Cou in epithelial cells (P < 0.01). These results indicate that Cou can disturb reproductive function by affecting reproductive hormone secretion and altering the endometrial milieu through PG stimulation. Coumestrol therefore may impair physiologic regulation of the estrous cycle and early pregnancy.