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Twenty outbreaks of Phalaris aquatica "sudden death" syndrome in sheep were investigated between 1981 and 1991. Four were confirmed and one was suspected, to be a cardiac disorder; 5 were confirmed and 3 were suspected, to be a polioencephalomalacic disorder; the aetiology of the remaining 7 outbreaks could not be determined. Potentially toxic levels of hydrocyanic acid (20 to 36 mg/100 g) were measured in the 3 toxic phalaris pastures tested. The measurement of potentially toxic levels of nitrate nitrogen (2920 micrograms/g) in toxic phalaris pastures by others, was noted. It is suggested that phalaris "sudden death" syndrome could have as many as 4 different underlying mechanisms, and that these might reflect the presence in the plant of a cardio-respiratory toxin, a thiaminase and amine co-substate, cyanogenic compounds, and nitrate compounds. 相似文献
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I Barja G Silván S Rosellini A Piñeiro MJ Illera JC Illera 《Reproduction in domestic animals》2008,43(6):701-707
The determination of gender in wild animals is essential for behavioural and ecological studies, and also for conservation. The objectives of this study were (i) the determination of gender in faecal samples of Iberian wolf based on the differential concentrations of sexual steroid hormones (SSH) and (ii) to analyse the profiles of SSH in males and females (considering the gender determination carried out previously) during the non‐reproductive and reproductive periods. The quantification of androgens (testosterone, T), progestin (progesterone, P) and oestrogen (oestradiol, E) was conducted by means of enzyme immunoassay. The k‐means conglomerate analysis showed that the 59 faecal samples grouped into three different conglomerates, considering SSH levels. Groups 1 and 2 showed higher levels of T than group 3. Therefore, the faecal samples included in groups 1 and 2 (17 samples) corresponded to males and those of group 3 (42 samples) to females. The levels of T + P + E and T/P were higher in the group of males than in the group of females. The results of this study also showed that levels of T in males were higher during the reproductive period than in the non‐reproductive period. However, the concentrations of P and E turned out to be higher during the non‐reproductive season. In females, the levels of the three hormones (T, P and E) were higher during the reproductive period. 相似文献