|Estell, Richard - Rick|
Submitted to: Ecological Society of America Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2004
Publication Date: 8/1/2004
Citation: Fredrickson, E.L., Koppa, J.S., Estell, R.E., Anderson, D.M., Havstad, K.M. 2004. Management effects on livestock use of landscapes: Protein supplementation [abstract]. 89th Annual Meeting, Ecological Society of America. p.166.
Technical Abstract: Over half of the Earth's land surface is grazed by livestock. The effects of livestock grazing on terrestrial ecosystems range from detrimental to beneficial depending on ecosystem attributes and livestock management. Understanding the ecological implications of livestock management decisions is central to successful human interactions with complex environments. For example, supplementing heifers with a 32% protein supplement concentrated heifer movements in areas near water and supplementation points. Prior to supplementation, animal movements were dispersed throughout the pasture. While concentrated movements are at times desirable, they can also trigger undesirable ecosystem trajectories. As part of a larger goal to better understand the ecological impacts of livestock grazing, we designed a study to examine the effects of protein supplementation, a common management practice, on livestock use of landscapes. Thirty-six multiparous, lactating, Angus x Hereford cows were randomly assigned to one of three treatments: (1) control (CON), no supplementation, (2) supplementation each day at 0700 (AM) with 0.75 kg of a 32% crude protein pellet, or (3) supplementation at 1300 (PM) each day with the same supplement. Fifteen days prior to the study, animals were allowed to become familiar with experimental procedures and the 2,425 ha study pasture described as Chihuahuan Desert grassland ecotype. Animals from each treatment were fitted with Lotek GPS collars and rotated into the study pasture for a period of 5 days for three rotations. Animal position was acquired every 5 minutes. Mean distance from water differed (P < .0001) across treatments (2.55, 2.09, and 1.53 km for CON, PM, and AM, respectively). Distance traveled per day also differed (P < .0001) across treatments (7.17, 7.20, and 7.96 km/day for CON, PM, and AM, respectively). The area encompassing daily activities (Jennrich-Turner estimate of home range) also differed (P < .0001; 4.3, 2.8, and 3.9 square km/day for CON, PM, and AM, respectively). Protein supplementation and timing of supplementation affect the spatial use of desert grasslands and is likely to have important ecological implications. Furthermore, research examining livestock impacts must do so with an understanding of the effects of management on livestock behavior.