Although grassland degradation is well known to increase the pathogenic bacteria abundance that live on and in the plants and soil, whether grassland degradation would further increase the fecal pathogenic bacteria in herbivore, and thus increasing the risk of animal and human diseases via environmental pollution, still remains elusive. Here, we investigated the effects of grassland saline-alkaline degradation on the fecal pathogenic bacteria of domestic ruminant-cattle, and also preliminarily explored the underlying mechanisms of influence via analyzing changes in nutrient intake from cattle that long-term grazing on undegraded and severely degraded grasslands, respectively. Our results showed that the relative abundance of pathogenic bacteria including Streptococcus, Mogibacterium and Alistipes were increased significantly in the cattle grazing on severely degraded grassland. Notably, the results for correlation analyses demonstrated that the Paludibacter had a positive effect on these three pathogenic bacteria. Moreover, we found that cattle grazing on severely degraded grassland showed an increased iron and sodium intake compared with those cattle grazing on undegraded grassland. Further, our results found that the Fe intake most contribute to the enhancement of the relative abundance of fecal Streptococcus and Paludibacter, whilst the Na intake most contribute to the increase in the relative abundance of fecal Alistipes. In general, our study highlights that Fe and Na intake could mainly affect the abundance of fecal pathogenic bacteria in cattle through two pathways, namely direct as well as indirect regulation of Paludibacter abundance. Our findings suggest that increasing grassland saline-alkaline degradation worldwide will not only greatly increases the risk of animal diseases, but also even poses a serious threat to human health through environmentally mediated transmission, and therefore, cattle grazing on severely degraded grassland should be prohibited.