title: Grazing as an alternative for utilization of saline-sodic soils in the San Joaquin Valley: selenium accretion and performance of beef heifers.
abstract: Two experiments were conducted to evaluate Se accumulation and health of non-pregnant, non-breeding beef cattle grazing on forages with a high Se content due to irrigation with saline drainage water. Heifers grazed experimental pastures of "Jose" tall wheatgrass (TWG; Thinopyrum ponticum var. "Jose") and creeping wildrye (CWR; Leymus triticoides var. "Rio") for 190 days in Experiment 1 (2007) and for 165 days in Experiment 2 (2008). In experiment 1, mean Se concentrations were similar in TWG and CWR herbage (4.0 versus 3.7 ± 0.26 mg/kg dry weight; p=0.34) as was crude protein (113 versus 114 ± 7.9 g/kg dry weight; p=0.94). Concentrations of Se in blood increased by 300% during the grazing period, and were similar for heifers grazing the TWG or CWR pastures (0.94 versus 0.87 ± 0.03 mg/kg; p=0.89). Heifers grazing on TWG gained more body weight than did heifers grazing on CWR (0.59 versus 0.27 ± 0.07 kg/days; p<0.01). In experiment 2, concentration of Se (4.0 versus 2.8 mg/kg ± 0.19 mg/kg dry weight; p<0.01) and crude protein (79 versus 90 ± 5.6 g/kg dry weight; p<0.01) differed, for TWG and CWR, respectively. Within 20 days, Se concentrations in blood had increased by 300% and by nearly 200% in heifers grazing on TWG or CWR. All data cited are least square means ± standard error of the mean. Data from our two grazing seasons are consistent in demonstrating the safety of grazing beef cattle for a period of up to 6 months on TWG and CWR forages having high levels of Se due to irrigation with saline drainage water. This suggests that forage production using saline drainage water is a viable alternative for saline soils with limited potential for producing high value, salt-sensitive, crops.
authors.affiliation: Department of Animal Science, University of California, Davis, CA 95616, USA. sdjuchem@gmail.com
authors.forename: Sérgio O
authors.initials: SO
authors.lastname: Juchem
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Benes
authors.forename: P H
authors.initials: PH
authors.lastname: Robinson
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Grattan
authors.forename: Pablo
authors.initials: P
authors.lastname: Vasquez
authors.forename: Pablo
authors.initials: P
authors.lastname: Chilibroste
authors.forename: Martin
authors.initials: M
authors.lastname: Brito
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002140:California; D002417:Cattle / Q000097:blood / Q000254:growth & development* / Q000378:metabolism*; D008099:Liver / Q000737:chemistry; D018482:Muscle, Skeletal / Q000737:chemistry; D006109:Poaceae / Q000737:chemistry; D011897:Random Allocation; D012621:Seasons; D012643:Selenium / Q000032:analysis / Q000097:blood / Q000378:metabolism*; D012987:Soil / Q000737:chemistry; D013054:Spectrophotometry, Atomic; D014867:Water / Q000737:chemistry; D015430:Weight Gain
chemical_list: D012987:Soil; D014867:Water; D012643:Selenium