Effects of feeding pregnant beef cows selenium-enriched alfalfa hay on selenium status and antibody titers in their newborn calves

Abstract

In newborn dairy calves, it has been demonstrated that supranutritional maternal and colostral Se supplementation using Se yeast or sodium selenite, respectively, improves passive transfer of IgG. In beef cattle, agronomic biofortification with Se is a more practical alternative for Se supplementation, whereby the Se concentration of hay is increased through the use of Se-containing fertilizer amendments. It has been previously demonstrated that agronomic Se biofortification is an effective strategy to improve immunity and performance in Se-replete weaned beef calves. The objective of this experiment was to determine the effects of feeding beef cows Se-enriched alfalfa () hay during the last 8 to 12 wk of gestation on passive transfer of antibodies to calves. At 10 wk ± 16 d before calving, 45 cows were assigned to 1 of 3 treatment groups with 3 pens (5 cows/pen) per treatment: Control cows were fed non-Se-fortified alfalfa hay plus a mineral supplement containing 120 mg/kg Se from sodium selenite, Med-Se cows were fed alfalfa hay fertilized with 45.0 g Se/ha as sodium selenate, and High-Se cows were fed alfalfa hay fertilized with 89.9 g Se/ha as sodium selenate; both the Med-Se and the High-Se groups received mineral supplement without added Se. Colostrum and whole blood (WB) were collected from cows at calving, and WB was collected from calves within 2 h of calving and at 12, 24, 36, and 48 h of age. Concentrations of IgG1 and J-5 antibody in cow colostrum and calf serum were quantified using ELISA procedures. Selenium concentrations linearly increased in WB ( < 0.001) and colostrum ( < 0.001) of cows and in WB of newborn calves ( < 0.001) with increasing Se concentration in alfalfa hay. Colostrum concentrations of IgG1 ( = 0.03) were increased in cows fed Se-biofortified alfalfa hay, but J-5 antibody ( = 0.43) concentrations were not. Calf serum IgG1 ( = 0.43) and J-5 antibody ( = 0.44) concentrations during the first 48 h of age were not affected by prior Se treatment of cows. These data suggest that feeding Se-biofortified alfalfa hay promotes the accumulation of Se and antibodies in colostrum but does not affect short-term serum antibody concentrations in calves.

Effects of feeding pregnant beef cows selenium-enriched alfalfa hay on passive transfer of ovalbumin in their newborn calves

“…As previously reported [20], fertilizing fields with increasing amounts of Na-selenate increased the Se concentration of third-cutting alfalfa hay from 0.34 mg Se/kg DM (non-fertilized control) to 2.42 and 5.17 mg Se/kg DM for Na-selenate application rates of 45.0 and 89.9 g Se/ha, respectively. Calculated Se intake from dietary sources was 8.3 (including 3 mg Se/head daily from Na-selenite), 27.6, and 57.5 mg Se/ head daily for cows consuming 70% alfalfa hay and 30% grass hay with Se concentrations of 0.34 to 2.42 and 5.17 mg Se/kg in the alfalfa hay DM, respectively.…”

“…We previously reported that concentrations of IgG1 in colostrum increased in a linear relationship to the amount of Se ingested by the dam [20]. The mechanism by which High-Se supplementation increases colostral IgG1 concentration is unknown, and multiple factors may be involved.…”

“…Because IgG concentrations were higher in colostrum of High-Se dams, their calves may have consumed more IgG1; however, this was not reflected in short-term (≤ 48 h) higher serum IgG1 concentrations in calves [20]. We previously hypothesized that calves reached the physiologic limitation for mass of Ig that can be passively transferred from a given volume of colostrum [26].…”

“…Based on our previous findings in dairy cows, the objective of this study was to determine if feeding Se-replete beef cows Se-enriched alfalfa (Medicago sativa) hay during the last trimester of gestation delays turnover and replacement of fetal intestinal epithelial cells in their calves, thus extending the period of time during which large proteins can be transferred from intestinal lumen to neonatal blood. We previously reported that feeding Se-biofortified hay to these pregnant beef cows improved Se status in cows and their offspring, as well as the IgG1 concentrations in colostrum compared to cows receiving control hay [20]. In this paper, to test the hypothesis that passive transfer is enhanced in calves born to cows fed Se-biofortified alfalfa hay in the last trimester of pregnancy compared to calves born to Control cows fed the USDA-approved upper limit of Na-selenite in salt [21], we administered 25 g oral ovalbumin (OVA) to calves at 12, 24, or 36 h after birth, and measured serum OVA concentrations to estimate the time of gut closure.…”

“…The tubes were centrifuged at 850 x g for 10 min at room temperature; serum was collected, transferred into 2.0 mL screw cap selfstanding micro tubes (ISC BioExpress, Kaysville, UT) and stored at -20°C until further analyses were performed. Concentrations of IgG1 in colostrum and calf serum were quantified using a direct sandwich ELISA procedure as previously reported [20]. Results are reported as mg/mL IgG1.…”