Mares parturition

The prostaglandin analog fluprostenol (250-500 jjLg i.m.) results in unpredictable delivery times and variability in the time from injection to foaling. In addition, pony mares not close to spontaneous parturition that were treated with fluprostenol delivered premature and weak foals that died shortly after delivery and treatment was associated with dystocia and retained fetal membranes. In contrast, when fluprostenol was given to mares that were close to spontaneous delivery, normal viable foals were bom (Bristol 1982). 

Mares usually expel the fetal membranes within 3h of parturition. If these membranes are retained for longer than 6h, the mare is at risk of developing metritis, septicemia, endotoxemia, laminitis and possibly death. 

The middle uterine, utero-ovarian or external iliac arteries may rupture during pregnancy or parturition, leading to signs of shock and colic or to the death of the mare. The therapy of rupture of these major blood vessels is somewhat controversial and may range from drugs that reduce blood pressure to those that increase circulating blood volume and pressure (Vivrette 1997). 

Bristol F 1982 Induction of parturition in near-term mares by prostaglandin F2 , Journal of Reproduction and Fertility Supplements 32 644... 

Ousey J C, Rossdale P D, Palmer L et al 2000 Effects of maternally administered depot ACTH(1-24) on fetal maturation and the timing of parturition in the mare. Equine Veterinary Journal 32 489-496 Pashen R L 1982 Oxytocin the induction agent of choice in the mare Journal of Reproduction and Fertility Supplements 32 645... 

Figure 5 Effects of varying levels of domperidone (1.1, 1.65, or 2.2 mg/kg, PO SID) on mammary gland development in periparturient mares grazing E+ fescue pastures. Day -31 represents the average number of days prior to the calculated date of parturition that pretreatment samples were obtained (pretreatment samples obtained 1.2 days before initiation of drug treatment). Stars indicate first detectable difference (P< 0.05) from pretreatment values within treatment. Numbers indicate number of animals remaining in treatment group when sample was obtained. (From Redmond, 1994.)...

Figure 6 Effect of endophyte-infected fescue and domperidone (1.1, 2.2, or 1.65mg/kg, PO, SID) treatment on serum prolactin levels in gravid mares. First detectable differences (P< 0.05) from pretreatment levels are indicated by stars. Unless otherwise indicated, data points represent four mares per treatment. Mares which were not showing signs of impending parturition 7 days after the calculated date of parturition (as determined by veterinary examination) were relocated to endophyte-free pasture. (From Redmond, 1994.)...

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