In the August of 1846, they lost around 36 cattle on the trail. They attempted to round them up, with little luck. During the Autumn of 1846, Native Americans apparently killed more than 100 of their cattle and oxen. The rest of their oxen were weak and they couldn't switch them out, so they had to rest them more frequently. By November, they had killed most of their remaining cattle for food. This must of had some sort of affect on how the trip turned out, because we all know what happened to the Donner party in the end, sadly.