Efficacy of selenium supplementation methods in California yearling beef cattle and resulting effect on weight gain

Abstract

Selenium (Se) deficiency occurs commonly in California grazing cattle and has been associated with reduced immune function and, in some studies, reduced weight gain. Multiple methods of supplementing Se are available, but little research has compared the effects of these methods on whole blood Se levels and weight gain. In two trials, we evaluated four methods of Se supplementation -an intrarumenal bolus, two injectable preparations and a loose salt containing 120 ppm Se -over an 85-to 90-day period in Se-deficient yearling cattle in Tehama County. The bolus treatment raised whole blood Se levels to an adequate level (0.08 ppm) for the entire study period. Whole blood Se concentrations in injected cattle initially reached adequate levels but then declined to deficient levels. The loose salt treatment acted slowly, with average whole blood Se concentration reaching adequate levels at the end of the study period. None of the treatments significantly affected weight gain and Se blood concentration was not correlated with weight gain. In growing cattle, it appears that Se supplementation may be viewed not as a direct driver of weight gain, but rather as similar to vaccination, in that it can prevent health problems that might otherwise lead to reduced weight gain.

Total Selenium Level and Its Distribution between Organs in Beef Cattle in Different Selenium Status

“…In the present study, 62.5% of heifers were found to be deficient in Se. Davy et al [58] report that selenium deficiency is common in cattle in California, with a mean selenium level of 0.18 mg/mL. In addition, lower levels of Se are observed in animals in Europe, which is likely due to the lower level of selenium in the soil in Europe compared to the USA [6,41,59,60].…”

Monensin and mineral supplementation economically increase yearling cattle weight gain on California annual rangeland

“…Cattle not supplemented had levels drop below the critical level of 0.08 mg/ml ( Davy et al, 2018 ), while supplemented cattle did not. Though the positive influence of adequate selenium in terms of immunity are well documented ( Spears et al, 1986 ; Arthur et al, 2003 ), recent work on California summer-irrigated pasture has not yielded a difference in weight gain between selenium deficient and adequate yearling cattle ( Davy et al, 2016 ). In this trial, yearling cattle on dryland range that attained adequate selenium through a mineral supplement alone outgained deficient control (salt only) cattle by 10%.…”

Mineral status of California beef cattle1

“…Mineral supplementation (yes or no) was broken into four different constituents of selenium supplementation (only ran with selenium level), copper supplementation (only run with the copper level), salt supplementation (only run with the sodium level), and broad supplementation (run with all other mineral levels). Selenium supplementation was defined as either a selenium oral bolus given within 1 yr (duration of benefit; Maas et al, 1994 ), a selenium injection given within the previous 45 d (duration of benefit; Davy et al, 2016 ), or a loose salt or liquid supplement containing the equivalent of at least 2 mg/hd/d estimated consumption. Copper supplementation included supplementation programs that had a copper bolus given within a year or a loose salt mix containing at least a 3,000 mg/kg equivalent with a mix designed at a 28 g/d consumption.…”

“…Their results found that less than 10% of Western state cattle fell below adequate selenium levels. Recently, Davy et al (2016) found that, when implemented, multiple methods can be successful in correcting selenium deficiency. Although Dargatz and Ross (1996) sampled only a small subset of California cattle, it may be that beef cattle manager’s supplement strategies had successfully corrected the high level of deficiency found in earlier work.…”