Simulated Ruminant Digestion Reduces Germination of Some Native Great Basin Species and Cheatgrass & Virtual Fences Successfully Contain Cattle Over a Wide Range of Stocking Densities and at Stubble Heights Below Common Riparian Management Targets
Loading...
Authors
Jero, Nathan
Issue Date
2022
Type
Thesis
Language
Keywords
Fecal seeding , Grazing management , Rangeland , Restoration , Virtual fence
Alternative Title
Abstract
This thesis reports the results of two projects related to the effective management of rangelands. Feeding seeds to cattle to be spread in feces has long been suggested, but the survival of seeds through the digestive tract varies widely and is species-dependent. I studied germination of seven species commonly used for restoration in the Great Basin, and cheatgrass, an invasive annual grass, after exposure to simulated ruminant digestion. Increasing rumen residence time decreased germination rates of all species tested. Previous research indicates that most seeds recovered in the feces of cattle are recovered 24-48 hours after ingestion. Of the species tested, only crested wheatgrass and squirreltail maintained appreciable levels of germination after 48 hours of digestion. These species may be suitable for spread by cattle. The viability of cheatgrass seed declined precipitously after 24 hours of digestion, indicating that cattle likely do not substantially contribute to the spread of cheatgrass through seed consumption.Virtual fences are an emerging animal management technology that use audio cues followed by a mild electrical pulse instead of physical barriers to contain animals. Virtual fences have long been conceptualized as a tool to help land managers achieve livestock production or land management goals, yet little research has focused on figuring out what factors influence virtual fence performance. We evaluated the effect of stocking density, the quantity of forage inside the paddock and the difference between the quantities of forage inside and outside the paddock on the effectiveness of a commercially available virtual fencing system. We tested the virtual fencing system at stocking densities from 5-20 animals/acre and measured stubble height as a proxy for the quantity of forage inside the paddock and the difference between the quantities of forage inside and outside the paddock. The predictability and controllability of the electrical pulse have been identified as key components of animal welfare associated with virtual fences, so we also evaluated the effect of stocking density, forage quantity, and the difference in forage quantities inside and outside the paddock on predictability and controllability. We found that neither stocking density, forage quantity, nor the difference in forage quantity inside and outside the paddock influenced the effectiveness of virtual fences or the predictability and controllability of the electrical pulse. This implies that virtual fences are likely to be reliable tools for livestock management in productive settings and for stocking densities up to 20 animals/acre and when stubble heights are at or below common management targets.