Cultural energy analysis of cool- and warm-season grass pasturing systems into cattle finishing Programs

Abstract Text: A four-year study integrating pasture and drylot feeding systems was used to assess cultural energy analysis of cattle production systems. Each year, 116 fall-born Hereford and Angus crossbred calves of similar genotypes were used. The calves were obtained April 15 following weaning and a preconditioning program. Following a two-week acclimation period in drylot on ground mid-bloom alfalfa hay, the calves were assigned to treatments by weight and color pattern. Treatments were: 1) placing calves on bromegrass pasture until mid-October, at which time they were removed and finished in drylot (OCT); 2) placing calves on bromegrass pasture until approximately July 1, at which time they were moved to drylot for finishing (JULY) ; 3) placing calves on bromegrass pasture until mid-June, at which time they were moved to warm-season pastures until being returned to bromegrass pasture from mid-August until sometime in October when they were placed in drylot for finishing (WARM); 4) placing 28 steers directly into drylot at the start of the tests (FEEDLOT). The bromegrass pasture consisted of 24 paddocks, each 1.7 acres in size. Each grazing treatment of 28 steers (except for 32 steers placed on warm grass pastures) was rotated among paddocks at 3- to 4-day intervals early in the season and at about 2-day intervals later in the season. An 82% concentrate diet containing whole shelled corn, ground alfalfa hay, and a protein-vitaminmineral supplement with ionophore and molasses was provided ad libitum daily in drylot. On pasture, calves were provided supplement blocks containing ionophore. Pens of cattle were harvested at approximately 568 kg. Cultural energy used for pasture establishment, feed consumption, and maintenance were calculated using the actual inputs and corresponding energy values from the literature. FEEDLOT cattle had higher and OCT cattle had lower total cultural energy expenditures than other treatments (P<0.01). Feed energy comprised more than half of the total cultural energy and was highest for FEEDLOT and was lowest for OCT cattle (P<0.01). Energy expended per kg live weight gain was higher for FEEDLOT cattle (P<0.01). The energy output ratio as defined by kcal input/kcal output was better for OCT and was followed by WARM treatment (P<0.01). Results show that pasturing cattle is an effective way of reducing cultural energy expenditure and grazing cool season grass was better suited to concept of sustainable agriculture.

Keywords: Cultural Energy; Feedlot; Pasture; Sustainability