Steer and Vegetation Response to Short Duration and Continuous Grazing

Abstract

Comparisons were made over a 4-year period between l-herd, 16pasture short duration grazing (SDG) and continuous grazing (CC) on the Texas High Plains. Animal performance, vegetation response, and diet quality were evaluated. Stocking rate on SDG was equal to that on CC the fhst year (13.3 ha/AU), double that on CG in the second year, and 1.5 times that on CG the third and fourth years. Average daily gain (ADG) of steers was the same (0.33 kg/day) between SDG and CG the first year. When stocking was doubled on SDG the second year, steers on SDG gained 0.15 kg/day compared to 0.25 kg/day under CG. In the third and fourth years, with stocking under SDG at 1.5 times that on CG, gains were similar. Standing crop biomass on SDG fell below that on CG after 1 year of gradng. In the second year standing crop was greater (KO.05) on SDG than on CG, but in years 3 and 4, standing crop on the SDG was less than on CC. Changes in species composition were the same on both CC and SDG. Steer diet composition and quality were evrhtated during the growhtg season (May to October) of year 4. Steers on SDG consumed 15% more forbs (39% VI 24%) than steers on CC. No differences (BO.05) between CG and SDG were ohserved for dietary crude protein or in vitro digestible organic matter. SDG did not improve animal performance, diet quality, or forage l variability over CC when evahtated over 4 years. mance, (2) forage dynamics, and (3) diet quality. Methods and Procedures The study site was located in Lubbock County, Texas, on the Texas Tech University campus. At the initiation of the study, the area was considered a poor condition native shortgrass range site on an Amarillo fine sandy loam soil. Dominant grasses on the site were Bouteioua gracilis. Buchloe dactyloides. Panicum obtusum, Sporobolus cryptandrus, Aristida purpurea. and Bothriochloa saccharoides. Major forbs were Kochia scoparia, Zinnia grandiflora. Spharalcea coccinea, and Kuhnia sp. There also was a heavy infestation of Xanthocephalum sarothrae and Prosopisglandulosa. The climate is warm-temperate and continental with an average annual precipitation of 40 cm. Precipitation occurs mainly in the spring and late summer months. Temperature ranges from +40° C to-25" C with a frost-free growing season of 200 days. Mean elevation is 960 m. (SCS 1979).

Little Bluestem Tiller Defoliation Patterns under Continuous and Rotational Grazing

“…Continuous and rotational grazing systems differ little in terms of their effects on range condition in the short-term (Denny et al 1977, Pitts and Bryant 1987, Hart et al 1988, O'Reagain and Turner 1992. We hypothesize higher range condition in rotational system pastures will result in the long-term from increased vigor of desirable plants due to fewer defoliations during the grazing season.…”

Rangelands, Volume 22, Number 1 (February 2000)

“…Several studies have shown short-duration grazing to be similar to continuous grazing in effects on plant succession and range condition if stocking rates were the same (Pitts and Bryant 1987, White et al 1991, Manley et al 1997, Gillen et al 1998. In a south Texas study, it was found that progressively increasing the stocking rate under short-duration grazing up 2.5 times the rate recommended by Merrill (1954) caused the frequency and composition of mid-grasses to decline but shortgrasses were not affected (Ralphs et al 1990).…”

“…Four studies have shown short-duration grazing has lowered individual livestock productivity compared to continuous or season-long grazing (Parker et al 1987, Anderson 1988, Heitschmidt et al 1990, McCollum et al 1999. Another 5 studies showed no difference between short-duration and continuous grazing (Jung et al 1985, Pitts and Bryant 1987, Olson and Malechek 1988, Taylor et al 1993, Manley et al 1997) while 1 study showed short-duration grazing increased livestock productivity (Daugherty et al 1982). A careful analysis of these 10 studies indicates small or no difference in livestock productivity between short-duration and continuous grazing if stocking rates are equal with one exception.…”

“…Several studies now show that there is little difference in forage production between short-duration and continuous grazing systems if stocking rates are the same (Jung et al 1985, Pitts and Bryant 1987, Anderson 1988, Thurow et al 1988, White et al 1991, Manley et al 1997). In a 6 year study on blue grama rangeland in south-central New Mexico, total grass production averaged 828 lbs acre-' under continuous grazing compared to 724 lbs acre-' under short-duration grazing.…”

Virtual herding for flexible livestock management – a review

“…Furthermore, herding is impractical if not impossible in large cattle herds (Hunt et al 2007). Even though herding can facilitate appropriate use, man's fallibility in consistently making correct choices has not always shown herding to improve livestock distribution (Pitts and Bryant 1987) or positively benefit the amount of forage and its nutritive value; therefore, VF will only be as good as those who operate this virtual herding system.…”