Trace Mineral Status Research Articles

Effect of trace mineral source on mineral status and performance of beef steers fed low- or high-sulfur diets.

A 2 × 2 factorial assessed the effect of trace mineral (TM) sources fed within low- or high-S diets on the mineral status and performance of cattle. Angus crossbred steers ( = 48; 6/pen) were blocked by BW (316 ± 16.6 kg), assigned to low-S (0.27%; LS) or high-S (0.54%; HS; added as CaSO) diets, and supplemented TM at 10 mg Cu, 30 mg Zn, and 20 mg Mn/kg DM from hydroxy (HYD; IntelliBond; Micronutrients USA LLC, Indianapolis, IN) or inorganic (sulfates; ING) sources ( = 12 steers/treatment). Steers were fed corn silage and corn-based diets via GrowSafe bunks in the growing period (GP; 84 d) and finishing period (FP; 77 d), respectively. Plasma and liver were collected at trial initiation and end of GP and FP for mineral concentrations. End of GP and FP red blood cell lysate superoxide dismutase (SOD) and Mn-SOD activity and liver glutathione concentrations were measured. Data were used as a 2 × 2 factorial using Proc Mixed of SAS (SAS Inst. Inc., Cary, NC) with initial plasma and liver status analyzed as covariates. High S decreased ( < 0.01) liver Cu and tended ( ≤ 0.10) to decrease plasma Cu concentrations. Liver Cu concentrations were lower in HYD than ING in the FP ( < 0.01). High S decreased ( = 0.04) GP plasma Zn concentrations and tended to decrease ( = 0.10) GP liver Zn. There were GP ( = 0.05) and FP ( = 0.02) S × TM effects for liver Mn concentrations where GP LS-HYD was greater than all other treatments, whereas FP LS-HYD was lower than HS-HYD and LS-ING and FP HS-ING was less than LS-ING. Glutathione, SOD, and Mn-SOD were not different ( ≥ 0.13) in the GP, but S × TM tended to affect FP Mn-SOD ( = 0.10), where LS-HYD tended to be lower than LS-ING. Oxidized glutathione in FP tended to be lower ( = 0.06) for HYD than ING. In the GP, there were S × TM effects on performance where LS-HYD had greater ADG and G:F ( ≤ 0.05) than HS-HYD, whereas LS and HS-ING were intermediate. For FP performance S × TM effects were noted where LS-HYD and HS-ING tended ( = 0.10) to gain more than HS-HYD and HS-HYD had lower G:F ( = 0.04) than HS-ING. There were no effects of S × TM on final BW, DMI, or ADG ( ≥ 0.11); however, HS-HYD had lower G:F than other treatments overall ( = 0.05). High S decreased back fat and yield grade ( = 0.03), and rib eye area was smaller for HYD than ING ( = 0.02). In this study HS decreased markers of Cu and Zn status, and differential effects of HYD vs. ING minerals were noted across dietary phases, although all steers maintained adequate TM status.

Prognostic Indicator for Clinical Babesiosis in Cattle

Present Study has been carried out on the animals suffering from clinical bovine babesiosis in the Patna districts of Bihar, India. A total number of 36 lactating cows of different breeds and ages were included in the study to develop a prognostic indicator card for better and economic management of disease. There are two types of prognostic indicator systems that has been evolved viz numerical and categorical on the basis of oxidant marker, antioxidant status, trace mineral status, hematological changes and vital parameter changes between dead and survived suffering animals. Erythrocytic LPO in succumbed cases were significantly (P less than 0.01) higher than recovered ones. GPx, SOD and catalase in succumbed cases were significantly (P less than 0.01) lower than recovered ones. Trace elements Zn, Cu and Se in succumbed cases were significantly (P less than 0.01) lower than recovered ones. The body temperature, respiration and heart rate in dead cases were significantly (P less than 0.01) higher than recovered ones. In conclusion, Prognostic indicator card developed in the present study may be helpful in the management of clinical babesiosis in field condition

637 Effect of repeated trace mineral injections on beef heifer development and reproductive performance

To determine the effects of repeated trace mineral injections on heifer development and reproductive performance, commercial Angus heifers ( n = 290; 199 ± 34.3 kg) were utilized in a completely randomized design. Heifers were stratified by BW into 6 groups and assigned to injectable trace mineral (MM; Multimin90) or saline injection (CON) given post-weaning at 221, 319, and 401 ± 22 d of age. Throughout development, heifers grazed endophyte-infected fescue-red clover pastures and were supplemented with modified corn distillers grains (2.7 kg·heifer-1·d-1) and given access to free choice inorganic minerals formulated to meet or exceed NRC recommendations. Heifer BW and BCS were collected at trial initiation and 4-7 week intervals thereafter. Hair coat scores (HCS) and respiration rates (n = 30 heifers/treatment) were collected at 269, 310, and 361 ± 22 d of age. Additionally, blood and liver samples were collected at trial initiation and estrous synchronization from 30 heifers/treatment to determine trace mineral status. At 319, 372, and 421±22 d of age, antral follicle count and ovarian size were determined via ultrasonography. Two blood samples from all heifers were collected 10 d apart, concurrent with ultrasound dates, for puberty determination. Estrous synchronization was initiated and reproductive tract scores (RTS) were collected at 421±22 d of age. Heifers had AI at 430 ± 22 d of age. Heifer BW, BCS, and HCS did not differ (P ≥ 0.12) throughout development, except at 268 ± 22 d of age when BCS was greater (P = 0.03) for MM than CON. Respiratory rates were greater (P = 0.05) for MM than CON at 269±22 d of age, but did not differ (P ≥ 0.66) at 310 and 361 ± 22 d of age. Plasma Mn and Zn concentrations did not differ between treatments (P ≥ 0.54). However, MM had greater (P ≤ 0.01) plasma and liver concentrations of Cu and Se compared to CON. Interestingly, MM decreased (P = 0.02) liver Zn concentrations compared to CON and there was no difference (P = 0.60) in liver Mn concentrations. Antral follicle count and ovarian size did not differ (P ≥ 0.43) between treatments. Throughout development, the number of pubertal heifers was less (P < 0.01) for MM than CON. However, there was no difference (P ≥ 0.26) in RTS or AI pregnancy rates (36 and 37% for MM and CON, respectively). Supplementing an injectable trace mineral increased heifer Cu and Se status; however, no effect was noted on ovarian development or reproductive performance.

The effects of injectable trace minerals on growth performance and mineral status of Angus beef steers raised in a natural feedlot program

To evaluate the effects of an injectable trace mineral (TM) on TM status and growth of feedlot steers raised in a Certified Angus Beef Natural system, 168 certified natural Angus steers (359 ± 36.6 kg), blocked by initial BW into pens of 6 head, received a sterilized saline (SAL, n = 84) or Multimin90 (ITM, n = 84) injection (1.47 mL/100 kg of BW). Steers were grown on a corn silage–based diet for 56 d and transitioned, and on d 84 they began a dry-rolled corn–based finishing diet. On d 84 steers were assigned equally within treatment, SAL or ITM, to receive a second injection, making 4 total treatments: (1) d 0 SAL, d 84 SAL (SAL/SAL, n = 42); (2) d 0 SAL, d 84 ITM (SAL/ITM, n = 40); (3) d 0 ITM, d 84 SAL (ITM/SAL, n = 40); and (4) d 0 ITM, d 84 ITM (ITM/ITM, n = 42). Liver Cu and Se concentrations were greater (P ≤ 0.01), and liver Zn concentrations tended (P = 0.07) to be greater in ITM versus SAL steers on d 14. Liver Zn and Mn were not different on d 98 (P ≥ 0.64). Liver Cu (P = 0.02) and Se (P < 0.001) concentrations were greater in SAL/ITM and ITM/ITM on d 98. Injectable TM had no effect on growing or finishing BW or G:F (P ≥ 0.14). Steers had adequate TM status throughout the trial, likely explaining the lack of performance differences due to TM treatment.

DISEASE COMPLEXITY IN A DECLINING ALASKAN MUSKOX (OVIBOS MOSCHATUS) POPULATION.

The muskox ( Ovibos moschatus ) population inhabiting the eastern North Slope (ENS) of Alaska, US declined dramatically during 1999-2006, whereas populations in western Alaska (WA) were stable or increasing. To understand morbidity and mortality factors contributing to the decline, Alaska Department of Fish and Game conducted pathologic investigations of carcasses from 2005 until 2008. Additionally, archived sera from both ENS and WA muskoxen collected during 1984-92, before the documented beginning of the ENS decline; sera collected during 2000, near the beginning of the decline; and contemporary sera (from live capture-release, adult females) collected during 2006, 2007, and 2008 were analyzed to determine whether prevalence of antibody to potential pathogens differed in the two areas or changed over time. The pathogens investigated were those that were believed could cause lameness or poor reproduction or adversely affect general health. Furthermore, trace mineral levels, hemograms, and gastrointestinal parasites were evaluated in live adult females captured 2006-08. Pathologic investigations identified several comorbid conditions, including predation, polyarthritis caused by or consistent with Chlamydophila spp. infection, hoof lesions, copper deficiency, contagious ecthyma, verminous pneumonia, hepatic lipidosis suggestive of negative energy balance, and bacterial bronchopneumonia due to Trueperella pyogenes and Bibersteinia trehalosi . Pathogens suspected to be newly introduced in the ENS muskox population on the basis of serologic detection include bovine viral diarrhea, respiratory syncytial virus, Chlamydophila spp., Brucella spp., Coxiella burnetii , and Leptospira spp., whereas parainfluenza virus-3 antibody prevalence has increased in the WA population. Although multiple disease syndromes were identified that contributed to mortality and, in combination, likely limited the ENS muskox population, further holistic investigations of disease agents, trace mineral status, and nutritional factors in conjunction with intensive demographic and environmental analyses would provide a better understanding of factors that influence Alaskan muskox populations.

1263 Impacts of zinc, manganese, and copper source on mature bull trace mineral status and spermatozoa characteristics

1263 Impacts of zinc, manganese, and copper source on mature bull trace mineral status and spermatozoa characteristics

The effects of increasing supplementation of zinc-amino acid complex on growth performance, carcass characteristics, and inflammatory response of beef cattle fed ractopamine hydrochloride.

Forty-two Angus crossbred steers (380 ± 5.3 kg) were enrolled in a finishing study to evaluate the influence of a supplemental Zn amino-acid complex (ZnAA; Availa-Zn) on performance and carcass characteristics of finishing steers in combination with ractopamine hydrochloride (RAC). Steers were stratified by BW into 7 pens of 6 steers each, and individual feed intake was measured. Steers were assigned to 1 of 4 treatments for 86 d (pre-RAC period): a dry-rolled corn-based diet supplemented with 60 mg Zn/kg DM from ZnSO and no supplemental ZnAA (CON; analyzed 88 mg Zn/kg DM; = 6) or CON diet supplemented with 30 (Zn30; = 12), 60 (Zn60; = 12), or 90 (Zn90; = 11) mg Zn/kg DM from ZnAA. Day 86 BW and G:F displayed a quadratic tendency ( = 0.09) with Zn60 steers being greater than the other treatments. Plasma cyclic adenosine monophosphate tended to linearly increase with increasing ZnAA ( = 0.10). On d 88, 6 of 12 steers (one of the 2 pens) receiving supplemental ZnAA was randomly selected to be supplemented with RAC at 300 mg∙steer∙d for the final 28 d of the experiment (RAC period). This created 7 final treatments: CON: no supplemental ZnAA, no RAC ( = 5); Zn30: Zn30, no RAC ( = 5); Zn30R: Zn30 + RAC ( = 6); Zn60: Zn60, no RAC ( = 6); Zn60R: Zn60 + RAC ( = 6); Zn90: Zn90, no RAC ( = 5); and Zn90R: Zn90 + RAC ( = 6). During the RAC period, as supplemental ZnAA increased within RAC-supplemented treatments, there was a linear increase in final BW, ADG, and G:F ( < 0.05). However, there was no effect of supplemental ZnAA on BW, ADG, or G:F during this period in non-RAC fed steers ( ≥ 0.44). Day 111 plasma Cu was increased, plasma Fe decreased, and leukocyte counts and serum interleukin-8 concentrations were greater ( < 0.05) in RAC-fed steers suggesting that RAC may elicit a mild inflammatory response. There was a tendency for increasing Zn supplementation to decrease plasma haptoglobin within RAC-fed steers ( = 0.07), suggesting that Zn may alter the inflammatory response. Overall, Zn60 improved growth performance during the pre-RAC period. Zinc supplemented as ZnAA appears to improve growth in combination with RAC supplementation, suggesting that Zn may enhance or support the biological function of RAC. Additionally, these results indicate that feeding RAC impacts trace mineral status, and potentially causes a non-specific inflammatory response, but further research is required to define this response.

Short communication: Iodine concentrations in serum, milk, and tears after feeding Ascophyllum nodosum to dairy cows-A pilot study.

Kelp (Ascophyllum nodosum) is rich in iodine and often fed by organic dairy producers as a mineral supplement to support animal health. A commonly held belief is that kelp supplementation decreases susceptibility to infectious bovine keratoconjunctivitis due to increased iodine concentrations in tears. Whereas serum and milk iodine concentrations are positively correlated and modulated by oral iodine supplementation, nothing is known about the iodine concentration of tears. Therefore, the 3 objectives of this pilot study were to determine (1) the iodine content of tears, milk, and serum of cows after being fed kelp for 30d; (2) the trace mineral and thyroid status of cows before (d 0) and after being fed kelp for 30d; and (3) the in vitro growth rate of bacteria in tears (Moraxella bovis) or milk (Staphylococcus aureus, Escherichia coli, Streptococcus uberis) collected from cows fed no kelp (d 0) or kelp (d 30). Cows (n=3/treatment) were individually fed 56g of kelp per day (n=3/treatment) or not (n=3/no treatment) for 30 d. Daily feed intake of the TMR was recorded and weekly TMR, kelp, milk, blood and tear samples were collected and analyzed for iodine. The feed samples were pooled and further analyzed for other minerals. On d 0 and 30, liver biopsies and blood samples were collected and analyzed for mineral content and thyroid hormone concentrations, respectively. An inhibition test used milk and tear-soaked plates from kelp-fed cows (d 0 and 30) as well as 1 and 7.5% iodine as positive and distilled water as negative control. As expected, serum iodine concentrations were positively correlated with milk and tear iodine concentrations. Whereas the iodine concentrations in serum increased significantly in the kelp-fed cows during the 30-d study, milk and tear iodine concentrations increased only numerically in these cows compared with the control group. Liver mineral profiles were comparable between groups and generally did not change over the course of the study. Thyroid hormones remained overall within the reference range throughout the trial. Neither milk nor tears from kelp-fed cows inhibited in vitro growth of any of the plated bacteria. In summary, serum iodine concentration was correlated with the iodine concentration in milk and tears and feeding kelp increased only the serum iodine levels of cows in this trial. Bacterial growth was not inhibited in milk and tears of kelp-fed cattle in vitro, and prevention of infectious bovine keratoconjunctivitis would not be based solely on increased iodine concentrations in tears.

Evaluation of trace element and mineral status and related to levels of amino acid in children with phenylketonuria.

The aim of the present study was to examine trace elements (Zn, Cu, Mn, Se, Fe, Co, Cr, Ni, Cd, Pb), minerals (Ca, Mg, K), amino acids status in children with phenylketonuria and also whether they were correlated with each other in phenylketonuric patients. It has been found out that the HPA group was significantly lower than the control group with regards to Zn, Se, K, Ca, Mg and Zn/Cr levels (p<0.001, p<0.01, p<0.001, p<0.01, p<0.01 and p<0.001 respectively). In the patients with HPA, significantly strong positive correlations were observed between magnesium and calcium (r=0.791; p=0.001), also, indicates negative significant correlation between the concentrations of magnesium and phenylalanine (r=-0.591; p=0.026). The results of this study showed that, in the HPA group, phenylalanine-Mg relationship found, the presence of disease will in the evaluation of phenylalanine and other amino acids, together with the value of magnesium is required to consider.

Effects of a long-acting trace mineral rumen bolus supplement on growth performance, metabolic profiles, and trace mineral status of growing camels.

A study was conducted to evaluate the effects of a long-acting trace mineral rumen bolus (TMB) supplement on the productive performance, metabolic profiles, and trace mineral status of growing camels under natural grazing conditions. Fifteen 6-month-old growing male camels (average bodyweight 139.51 ± 26.49 kg) were used in a 150-day trial. Animals were individually housed in a shaded pen and randomly assigned to receive zero (control group, CON), one (TMB1), or two (TMB2) long-acting TMBs. Feed intake was measured weekly, and camels were weighed monthly. Blood samples were collected from all camels on days 1, 30, 60, 90, 120, and 150 to obtain metabolic profiles. Zinc, selenium, copper, cobalt, and manganese concentrations were determined in the diet, serum, and liver. In comparison with controls, giving camels one TMB increased the average daily gain (14.38%; P < 0.04) and feed efficiency (13.68%; P < 0.01). Additionally, the serum and liver concentrations of zinc, copper, selenium, cobalt, and manganese were greater (P < 0.01) in camels in the TMB2 group. These data indicate that TMB supplementation has positive effects on the growth performance and trace mineral profiles of camels. Different levels, sources, and synergistic combinations of trace minerals can be used in further studies to elucidate their abilities to increase productive variables as well as their availability and cost to the camel industry.

Status and Interrelation of Trace Minerals and Steroid Hormones in Heifers

Status and Interrelation of Trace Minerals and Steroid Hormones in Heifers

Can Outcomes be Improved in Dialysis Patients by Optimizing Trace Mineral, Micronutrient, and Antioxidant Status?: The Impact of Vitamins and their Supplementation.

Can Outcomes be Improved in Dialysis Patients by Optimizing Trace Mineral, Micronutrient, and Antioxidant Status?: The Impact of Vitamins and their Supplementation.

Can Outcomes be Improved in Dialysis Patients by Optimizing Trace Mineral, Micronutrient, and Antioxidant Status?: The Role of Trace Elements.

Can Outcomes be Improved in Dialysis Patients by Optimizing Trace Mineral, Micronutrient, and Antioxidant Status?: The Role of Trace Elements.

Can Outcomes be Improved in Dialysis Patients by Optimizing Trace Mineral, Micronutrient, and Antioxidant Status?: The Impact of Probiotics and a High-Fiber Diet.

Can Outcomes be Improved in Dialysis Patients by Optimizing Trace Mineral, Micronutrient, and Antioxidant Status?: The Impact of Probiotics and a High-Fiber Diet.

Osteopathology and selenium deficiency co-occurring in a population of endangered Patagonian huemul (Hippocamelus bisulcus).

BackgroundAbout 1,000 endangered Patagonian huemul deer (Hippocamelus bisulcus) remain in Chile and 350–500 in Argentina. Most groups (>100) are not recovering, and prevalence of osteopathology in Argentina was at least 57%. Here I describe relevant cases of osteopathology from a Chilean population which, however, recently also provided data on trace mineral status, supporting the initial hypothesis that nutrition may be a primary etiologic factor. Additionally, recent data on bone chemical composition of Argentine cases and soil analyses are discussed.ResultsFluoride levels in Argentine cases with osteopathology were low and fluorosis was discarded as an etiological factor. Selenium deficiency occurred in 73% of huemul from the Chilean population which exhibited several cases with osteopathology. The pathophysiognomy included extensive erosion; tooth loss; porosification; perforations of palate, maxillar and mandibular bone with frequent exposure of tooth roots; and fractured mandibula. Areas currently used by remaining huemul have mainly acidic volcanic soils, which reduces selenium bioavailability: mean soil selenium levels from areas typically used by extant huemul were very deficient (0.19 ppm), corroborating documented overt selenium deficiency in local livestock and plants. The area of extant huemul is known to result in primary iodine deficiency in livestock which is aggravated by selenium deficiency.ConclusionsCurrently the most parsimonious explanation for frequent osteopathology and lack of numerical recovery are the combined effects of selenium and iodine deficiencies based on: osteopathology in a population of selenium deficient huemul; selenium deficient livestock, plants and soils; acidic soils; and regional primary iodine deficiency. The nexus between mineral nutrition and population dynamics of huemul may be due to constraints on their movements to fertile lowlands, including the elimination of historic migratory traditions, and concomitant elimination of source populations.

Comparison of National Research Council standards and industry dietary trace mineral supplementation strategies for yearling feedlot steers

A total of 360 steers (initial BW = 350 kg, SD = 28.1 kg) were used in a randomized complete-block-design experiment to determine the effects of trace mineral concentration and source on feedlot performance, carcass characteristics, liver trace mineral status, and diet in vitro solubility of Cu and Zn. Target treatments consisted of (1) basal diet; (2) basal diet supplemented with 10 mg of Cu from CuSO4, 30 mg of Zn from ZnSO4, 20 mg of Mn from MnSO4, 0.50 mg of I from ethylenediamine dihydriodide, 0.10 mg of Se from Na2O3Se, and 0.10 mg of Co from CoCO3 per kilogram of DM (NRC); (3) basal diet supplemented with the same sources of Cu, Zn, Mn, I, Se, and Co as treatment 2 but provided at 20, 100, 50, 0.50, 0.20, and 0.20 mg of mineral/kg of DM, respectively (CNI); and (4) basal diet supplemented with 66.6% inorganic and 33.4% organic Cu, Zn, and Mn and inorganic forms of Co, I, and Se at iso-concentrations to treatment 3 (CNO). No differences (P > 0.10) between treatments for feedlot performance; final liver Zn, Mn, Se, and Co concentrations; and carcass merit were observed. In vitro procedures were used to examine the solubility of Cu and Zn from the diets used for the feeding experiment. Dry matter disappearance was similar across treatments (P > 0.10). Percentage of Cu and Zn solubilized after simulated rumen and abomasal digestion was less (P < 0.05) for the basal diet compared with NRC, CNI, and CNO diets and NRC compared with CNI and CNO diets. Under the conditions of this experiment, it appears that basal dietary concentrations of trace mineral were adequate for growth and performance of finishing yearling feedlot steers.

Could a trace mineral deficiency be associated with congenital chondrodystrophy of unknown origin (CCUO) in beef cattle in Australia?

Congenital chondrodystrophy of unknown origin (CCUO) has been reported in beef cattle worldwide. A trace mineral deficiency in pregnant dams has been suggested as causing the deformities seen in CCUO calves. An extended outbreak of CCUO in Australia between 2002 and 2009 provided an opportunity to examine the pattern of trace mineral status in gestating cows and the effect of parenteral trace mineral supplementation on a herd at risk of CCUO calves. A property with a strong history of CCUO was identified from a previous case-control study. A randomly selected sample of multiparous (8 to 10 years old) Angus and Angus cross cows (n = 20) was assigned to control (no injection) or supplement group given three injections at the recommended dose rate of chelated mineral supplement (Mn, Zn, Cu and Se) at 6-week intervals in mid- to late gestation. Liver biopsies were performed to measure liver Mn, Zn, Cu and Fe at each injection time and 1 month post-calving. Pasture samples were also collected for analysis. Supplemented cows had higher liver Cu levels compared to control cows (p < 0.001), but there was no difference between supplement and control cows for liver Zn, Fe or Mn. Liver Cu (p < 0.001), Fe (p < 0.001) and Zn (p < 0.001) fell during gestation and liver Mn increased after calving (p < 0.001). Three cows from the control group and two from the supplement group had liver zinc levels below the normal values at the end of the trial. Two cows from the control group and one from the treatment group gave birth to cows with signs of CCUO including superior brachygnathia. All cows except one from the control group had rough dry coats with excessive dander. The role of trace mineral status in the birth of CCUO calves, especially the role of zinc deficiency, requires further investigation.

Trace mineral status of rambouillet crossbred sheep in shivalik hills of Jammu

A baseline survey was conducted to know the trace mineral status of Rambouillet crossbred sheep reared in Shivalik hills of Jammu division. Atotal of 81 plasma samples were collected from 16 flocks along with samples of local grasses (29), fodder tree leaves (9) and soil (53). Based on age, management adopted and agro-climatic zone, animals were grouped. The overall average values of copper, iron, zinc, manganese and cobalt in plasma samples were 24.45±0.99, 38.31±3.10, 25.81±2.83, 2.93±0.38 and 6.46±0.42 μmol/l, respectively revealing sub-clinical deficiency of copper, iron and zinc. Sheep reared under organized management system were having higher levels of copper and manganese, whereas animals reared under un-organized management system showed higher levels of iron and zinc. Based on information mineral mixture for sheep of Shivalik hills of Jammu may be developed for improving productivity.

Effects of wet corn distillers grains with solubles on visceral organ mass, trace mineral status, and polioencephalomalacia biomarkers of individually-fed cattle.

Twenty-four steers (initial BW = 385 ± 1.1 kg) were blocked by BW and randomly assigned to 3 dietary treatments (0, 30, or 60% wet distillers grains with solubles [WDGS]; DM basis) and were fed individually to determine the effect of WDGS on live growth and carcass performance, visceral organ mass, trace mineral status, and polioencephalomalacia biomarkers. Steers were slaughtered at 125, 150, 164, and 192 d (2 blocks/slaughter date) when external fat depth was approximately 1.3 cm based on visual appraisal. Steers fed 30% WDGS had greater DMI than those fed 0 or 60% WDGS (P < 0.05), and steers fed 60% WDGS had the lowest carcass-adjusted ADG (P < 0.09) of the 3 treatments. Nonetheless, WDGS concentration did not alter feed efficiency (P > 0.41) on either live or carcass-adjusted basis. Steers fed 30% WDGS had greater liver S and Mn concentrations (DM basis) and lower liver Fe concentrations than control steers (P < 0.10; initial values used as a covariate), and feeding 60% WDGS decreased liver Cu and increased liver Fe (P < 0.10) compared with feeding 30% WDGS. Cytochrome c oxidase (COX) activity in brain tissue tended to be decreased with 60 vs. 30% WDGS (P = 0.12), and COX activity decreased linearly (P = 0.06) in lung tissue as dietary WDGS concentration increased. Likewise, gut fill linearly increased (P = 0.01) with increasing WDGS concentration. Feeding 30% WDGS increased fractional mass (g/kg of empty BW) of the small intestine (P < 0.10) compared with controls, whereas 60% WDGS increased fractional kidney mass (P < 0.10) compared with 30% WDGS. Overall, results suggest that gut fill, Cu status, and COX activity seem to be compromised by WDGS when fed at 60% of diet DM in diets based on steam-flaked corn, which suggests a greater susceptibility to polioencephalomalacia.

Feeding ferric ammonium citrate to decrease the risk of sulfur toxicity: effects on trace mineral absorption and status of beef steers.

The objective of this study was to determine the effects of adding ferric ammonium citrate (FAC; 300 mg ferric Fe/kg DM) to a 0.51% S diet on diet digestibility, mineral balance, and 56-d performance of steers fed a high concentrate diet. Angus-crossbred steers (n = 18) were randomly assigned to 1 of 3 treatments: 1) control diet (0.21% S; CON), 2) CON + sodium sulfate (0.51% S; high S [HS]), and 3) the HS diet + 300 mg of ferric Fe from FAC/kg DM (0.51% S; HS+Fe). This study included 2 phases, 1) a metabolism trial (d -1 to 20) and 2) a 56-d feedlot trial (d 22 to 79). In phase 1, 2 groups of 9 steers (370 ± 9.5 kg) were adapted to diet (10 d) and metabolism stalls (5 d), and following the adaptation period, a 5-d total collection of feces and urine was conducted. Feed offered and refused was recorded daily, and diet digestibility and retention of Cu, Fe, Mn, and Zn was determined. In phase 2, steers (384 ± 11.9 kg) were individually fed their respective diet in feedlot pens for 56 d and ADG was determined. From each steer, jugular blood and a liver biopsy were collected on d -1, 41, and 72 and d -1 and 72, respectively, for mineral content. Ruminal hydrogen sulfide concentrations (n = 18) were determined on d -1, 9, 23, 31, 41, 51, 61, and 72. In phase 1, DMI (P = 0.02), fecal output (P = 0.06), and intake of Cu, Mn, and Zn (P ≤ 0.04) were less in steers consuming the high S diets than CON, but DM and OM digestibility and urine excretion of minerals were not different (P ≥ 0.12) due to treatment. As a percent of intake, urinary excretion of Cu tended (P = 0.07) to be greater in the HS steers than the CON and HS+Fe steers, which did not differ (P = 0.74). In phase 2, BW, ADG, and G:F were not different (P ≥ 0.29) due to treatment, but DMI was lesser (P < 0.01) in the HS+Fe steers than CON and HS steers, which did not differ (P = 0.13). Ruminal hydrogen sulfide concentrations were greater (P < 0.01) in the steers fed high S diets than CON but were not different (P = 0.86) among the high S diets. Plasma Cu, Fe, and Zn concentrations were not different (P ≥ 0.27) due to treatment on all days. Final liver Cu concentrations were lesser (P < 0.01) in the steers fed high S diets compared with the CON, while liver Fe, Mn, and Zn concentrations did not differ (P ≥ 0.28) among treatments. In conclusion, adding Fe to a high S diet did not affect DM or OM digestibility or trace mineral absorption and status of steers relative to the HS diet alone.