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em BORIS: Bern Open Repository and Information System - Berna - Suiça


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On the basis of the experiments carried out over various years, it was concluded that (1) grayling Thymallus thymallus and brown trout Salmo trutta are resistant to temperature-induced sex reversal at ecologically relevant temperatures, (2) environmental sex reversal is unlikely to cause the persistent sex ratio distortion observed in at least one of the study populations and (3) sex-specific tolerance of temperature-related stress may be the cause of distorted sex ratios in populations of T. thymallus or S. trutta.

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The incidence of uterine torsion in cattle is 0.5–1 per cent of all calvings and up to 30 per cent of all dystocia cases (Berchtold and Rüsch 1993). The unstable suspension of the bovine uterus is a predisposition cited by different authors (Pearson 1971, Schulz and others 1975, Berchtold and Rüsch 1993). Age of the cow, season and weight and sex of the calf have been inconsistently reported to be associated with uterine torsion (Distl 1991, Frazer and others 1996, Tamm 1997). Small amount of fetal fluids and a large abdomen may contribute to uterine torsion (Berchtold and Rüsch 1993). Furthermore, some authors describe a predisposition in the Brown Swiss breed (Distl 1991, Schmid 1993, Frazer and others 1996) and in cows kept in alpine regions (Schmid 1993). Uterine torsion is predominantly seen under parturition, and the degree of torsion is most often between 180° and 360°. The direction is counter-clockwise in 60–90 per cent of the cases (Pearson 1971, Berchtold and Rüsch 1993, Erteld and others 2012). Vaginal delivery is possible after manual detorsion or after rolling of the cow, whereas caesarean section has to be performed after unsuccessful detorsion or if the cervix is not dilating adequately following successful correction of the torsion (Berchtold and Rüsch 1993, Frazer and others 1996). Out of all veterinary-assisted dystocia cases, 20 per cent (Aubry and others 2008) to 30 per cent (Berchtold and Rüsch 1993) are due to uterine torsion. Many publications describe fertility variables after dystocia, but only Schönfelder and coworkers described that 40 per cent of the cows got pregnant after uterine torsion followed by caesarean section (Schönfelder and Sobiraj 2005).