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An experiment was conducted to evaluate the bioavailability of 5 sources of vitamin A. It was hypothesized that some vitamin A products have protective coatings that are more resistant than others to rumen destruction and that such protection would result in greater tissue concentrations of vitamin A. Fifty-three yearling Angus x Brahman cattle, consisting of 39 steers and 14 heifers, were stratified by BW and sex and randomly assigned to 6 high-concentrate diet groups receiving no vitamin A supplementation (control) or vitamin A supplemented from the following sources: Microvit A (Adisseo, Acworth, GA), Rovamix A (DSM, Parsippany, NJ), Sunvit A, Lutavit A, and Microvit A DLC (Adisseo). The vitamin A treatment groups were fed daily 80,000 IU of retinol/animal in a low-retinol concentrate diet (78.5% oats, 10% cottonseed hulls, 8% molasses, and 2% cottonseed meal; DM basis) and a free-choice, poor quality (low carotene) hay for 84 d. Every 28 d, BW was determined and liver biopsies and plasma were collected and analyzed for retinol concentrations. All retinol treatments showed significant increases in liver retinol concentrations compared with control animals (P < 0.0001), which steadily decreased over time. At all collection times, Microvit A led to numerically, but not significantly, greater concentrations of retinol in liver than did all other treatments. However, at the end of the experiment, there was no significant difference in liver retinol concentration among Microvit A, Rovamix A, Lutavit A, and Microvit A DLC diets. When liver retinol concentrations at all collection times were considered, Microvit A and Rovamix A appeared to provide the most bioavailable vitamin A.

The objectives of this 72-wk study were to evaluate and compare the effects of 6 dietary levels of inorganic Se on serum, whole blood, wool, and tissue Se concentrations and to determine the maximum tolerable level of Se for mature ewes during lamb production. Forty-one, 4-yr-old, range-type ewes (57.4 +/- 5.7 kg) were used in a completely randomized design with 6 dietary treatments. Sodium selenite was added to a corn and soybean meal-based diet to provide 0.2 (control), 4, 8, 12, 16, or 20 mg of dietary Se/kg to ewes during lamb production. Serum Se and ewe BW were measured at 4-wk intervals; whole blood Se and wool Se were measured every 12 wk; and samples of brain, diaphragm, heart, hoof, kidney, liver, and psoas major were collected at the termination of the experiment. Dietary Se did not affect ewe BW during the study (P = 0.69), and there was no treatment x time interaction. Serum Se increased linearly as dietary Se level increased (P < 0.001) and responded cubically (P = 0.02) over time. Selenium in whole blood increased linearly (P < 0.001) as supplemental Se increased. Wool Se increased linearly (P < 0.001) as dietary Se increased, and the response over time was quadratic (P < 0.001). Brain, diaphragm, heart, and psoas major Se increased (P < 0.05) linearly as dietary Se increased, liver Se responded quadratically (P < 0.05), and hoof and kidney Se increased cubicically (P < 0.05) as supplemental Se increased. In general, serum, whole blood, and tissue Se concentrations of ewes receiving 12, 16, or 20 mg of dietary Se/kg were greater (P < 0.05) than those of controls and ewes receiving less dietary Se. Although they were elevated in ewes receiving increased dietary Se, at no time did serum, whole blood, or wool Se concentrations reach levels previously reported as toxic, nor were clinical signs of Se toxicosis observed. Histopathological evaluation of liver, kidney, diaphragm, heart, and psoas major did not reveal evidence of Se toxicosis in ewes at any dietary Se level. Ewes under our experimental conditions and during the stresses of production were able to tolerate up to 20 mg of dietary Se/kg as sodium selenite for 72 wk. These findings suggest that the maximum tolerable level of inorganic Se for sheep is much greater than 2 mg/kg as was suggested previously. Experiments of longer duration and utilizing greater dietary Se concentrations are necessary to clearly define the maximum tolerable level.

Seven hundred fifteen crossbred (primarily British) calves purchased in southern Oklahoma and northern Texas auction barns were received at the Willard Sparks Beef Research Center, Stillwater, OK, and used to study effects of duration (days) of vitamin E feeding during a 42-d receiving period on animal performance, health, and serum cholesterol and vitamin E concentrations. Upon arrival, calves were blocked by load (seven loads), sorted by BW (light, n = 4 pens per load; and heavy, n = 4 pens per load), and assigned randomly to one of four dietary treatments (n = 2 pens per load; 14 pens per treatment). Experimental diets were formulated to provide 2,000 IU.calf(-1).d(-1) of supplemental vitamin E (dl-alpha-tocopherol acetate) for 0 (CON), 7 (E7), 14 (E14), or 28 (E28) d. Vitamin E was delivered in a pelleted supplement that was added to the basal diet in decreasing concentrations as DMI increased (2.0 kg of DMI = 6%; 4.0 kg of DMI = 4%; and 6.0 kg of DMI = 2%). Serum samples were collected on d 0, 14, 28, and 42 for determination of cholesterol, alpha-tocopherol (d 0, 28, and 42), and antibody (IgG) concentrations. Duration of vitamin E supplementation did not affect ADG (0.98 kg/d; P = 0.56) or G:F (0.189; P = 0.87). Serum cholesterol concentrations decreased (day effect; P < 0.001) for all treatments from d 0 (average = 127 mg/100 mL) to 14 (average = 62 mg/100 mL). Serum alpha-tocopherol decreased (day effect; P < 0.001) from d 0 (5.2 microg/mL) to 28 (1.8 microg/mL); however, on d 28, a greater (P < 0.001) serum alpha-tocopherol concentration was observed for E28 (3.4 microg/mL) calves than for CON (1.1 microg/mL), E7 (1.2 microg/mL), or E14 (1.5 microg/mL) calves. Respiratory disease was diagnosed in 64.6% of calves in this study. Medical costs were less (P = 0.08) for calves fed vitamin E for 28 d (4.88 dollars/calf) than for calves fed the control diet (6.29 dollars/calf). Carcass characteristics were not affected (P = 0.19 to 0.88) by dietary treatments. Supplemental vitamin E formulated for 2,000 IU.calf(-1).d(-1) had little influence on performance and overall health status of calves under our experimental conditions; however, the increased serum concentrations of alpha-tocopherol when vitamin E was fed for 28 d suggests that any potential effects of vitamin E on health status might be time-dependent.

The objectives of this investigation were to assess the relationship between chemical measures and imaging estimates (radiographic photometry and dual-energy x-ray absorptiometry) of bone mineral content in dairy cows and to evaluate the effects of parity, stage of lactation, and site of measurement (fused third and fourth metacarpal bone vs. caudal vertebrae 14 and 15) on bone mineral content. In a preliminary study, the caudal vertebrae were excised from 33 cows following slaughter. Samples were analyzed by radiographic photometry and then analyzed for mineral content chemically. In a second experiment, the caudal vertebrae and right front metacarpal (sample pairs) were excised from 107 Holstein cull cows following slaughter. Parity and days in milk (DIM) of the donor animals were obtained for 43 pairs of samples. Samples were grouped by parity (1, 2, 3, and >or=4) stage of lactation (Stage 1: <90 DIM, Stage 2: 90 to 150 DIM, Stage 3: 151 to 250 DIM, and Stage 4: >250 DIM). Samples were analyzed by radiographic photometry and dual-energy x-ray absorptiometry and then analyzed for mineral content chemically. In both experiments, the relationship between mineral content estimated via the imaging techniques and mineral content measured chemically was poor, likely because of the relative maturity of animals in the sample set and lack of variation in mineral content. Ash content was higher in the metacarpal than in the caudal vertebrae, as were concentrations of Mg (expressed as a proportion of bone ash). No effects of stage of lactation were observed on bone mineral in the caudal vertebrae, but in the metacarpal, P content (proportion of total mineral) was highest in second lactation cows. Total bone mineral content (ash) was not affected by parity in the metacarpal or caudal vertebra, but Ca and P content of the metacarpal increased with parity. Noninvasive imaging techniques are not sufficiently sensitive to detect changes in mineral content or composition of mature cows, and only modest changes in bone mineral were observed with stage of lactation and parity.

Fifty-two multiparous Holstein cows were randomly assigned to receive 0 or 20 mg of biotin/d starting at an average of 16 d prepartum and then switched to 0 or 30 mg of biotin/d from calving through 70 d postpartum to determine whether supplemental biotin would affect cow performance, hepatic lipidosis, and plasma metabolites. Mean concentration of biotin in plasma sampled weekly was greater in cows fed biotin (4.3 vs. 9.4 nmol/L). Postpartum dry matter intake as a percentage of body weight (3.9% vs. 4.0%), milk production (35.8 vs. 34.8 kg/d), and milk fat concentrations (3.59% vs. 3.69%) were similar between treatment groups. Milk from biotin-supplemented cows tended to have a greater concentration of protein (2.73% vs. 2.83%). Concentrations of plasma nonesterified fatty acids were lower at wk 2 (652 vs. 413 microEq/mL) and 4 (381 vs. 196 microEq/mL) postpartum in cows fed supplemental biotin. However, mean plasma concentrations of beta-hydroxybutyric acid were not affected by biotin supplementation. Mean concentration of plasma glucose was greater for lactating cows fed supplemental biotin (63.4 vs. 66.6 mg/dL). Biopsies of liver were taken at 2, 16, and 30 d postpartum. The triacylglycerol concentration in liver (wet basis) tended to decrease at a faster rate after d 2 postpartum with biotin supplementation compared with control cows. The potential mechanisms that link improved glucose status and decreased lipid mobilization in cows supplemented with biotin warrant further investigation.

The objective of this study was to test the hypothesis that serum biotin concentration and biotin balance (consumed - [urinary output + fecal output]) measured as total avidin-binding substances (biotin + biotin metabolites) are responsive to changes in the proportions of dietary alfalfa meal and concentrate fed to sheep. Eight sheep (initial BW = 40 kg) consumed a pelleted alfalfa meal-based diet that had 95:5, 48:52, 23:77, or 9:91% alfalfa meal:concentrate ratios (DM basis) in a replicated 4 x 4 Latin square design with 20-d periods (10 d of acclimation, 7 d of adaptation, and a 3-d collection period with jugular blood drawn on the last day). Replacing alfalfa meal with concentrate in the pelleted diets decreased dietary concentrations of biotin proportionally. As the percentage of alfalfa meal in the diet decreased, there was a linear decrease in daily DM intake (1,128 to 901 g of DMI/d; P < 0.01), with a linear (P < 0.01) and quadratic (P < 0.01) increase in the apparent total-tract DM digestibility of diets (51.0 to 80.0%). The biotin consumed decreased with alfalfa meal proportion in the diet (linear, P < 0.01). Both fecal biotin concentration (linear, P < 0.01) and fecal biotin output (quadratic, P < 0.05) increased, reaching peaks at 23% alfalfa meal. Fecal biotin output was not correlated with biotin intake, DMI, or intake of digestible DM. Mean urinary output, urinary biotin concentration, urinary biotin output, and serum biotin concentration were not affected by treatments. Means of biotin balance were negative and revealed the same trends among treatments as did fecal output. Biotin balance was a quadratic (P < 0.05) function of decreasing alfalfa meal in the diet, with more negative values at the alfalfa meal:concentrate ratio of 23:77. Results suggest that the greatest synthesis of biotin in the total digestive tract occurs with diets of either 52 or 77% concentrate for sheep; however, research addressing the significance of biotin metabolites on biotin balance and plasma biotin pool is needed.

Understanding the determinants of animal abundance has become more vital as ecologists are increasingly asked to apply their knowledge to the construction of informed management plans. However, there are few general models are available to explain variation in abundance. Some notable exceptions are studies of folivorous primates, in which the protein-to-fiber ratio of foods has been shown to predict biomass. Here we examine the generality of Milton's [American Naturalist 114:363-378, 1979] protein/fiber model by providing a detailed analysis of diet selection in black-and-white colobus monkeys (Colobus guereza), and applying the model to populations shown to be stable; an assumption not previously examined. Based on observations of two groups of black-and-white colobus in Kibale National Park, Uganda, and one group in a forest fragment, we documented that the animals selected young leaves that had more protein, were more digestible, and had a higher protein-to-fiber ratio than mature leaves. The mature leaves did not differ from young leaves with respect to secondary compounds or mineral content (with the exceptions of copper and zinc). All of the colobus groups selected foods with a high protein-to-fiber ratios. However, one group also selected more digestible foods, and in another group, foraging efforts were positively related to zinc and negatively related to potassium. Previous studies that examined Milton's protein/fiber model did not demonstrate that the study populations were stable. If some populations were not at carrying capacity, then the correlations drawn between food availability and/or quality and folivore biomass may have been spurious. To address this issue, we censused a series of forest fragments in 1995 and again in 2000. We found that the populations in these fragments had declined from 165 in 1995 to 119 animals in 2000. However, based on evidence of population stability and lack of forest disturbance, we concluded that five of the original populations were stable. The biomass of these populations was related to the protein-to-fiber ratio of the fragment's trees. Combining our data with published data, we demonstrate that the protein-to-fiber ratios of mature leaves available to these folivorous primates accounted for 87% of the variance in their biomass., (Copyright 2004 Wiley-Liss, Inc.)

Experiments were conducted to test whether enhancement of antioxidant status could improve fertility and milk yield in dairy cows and resistance of cultured embryos to heat shock. Three experiments in three herds were performed to evaluate the effect of multiple intramuscular injections of 500 mg of vitamin E and 50 mg of selenium at 8 to 21 d before expected calving and at 30 and 80 d postpartum on reproduction of lactating Holstein cows. Vitamin E and selenium injections did not improve reproductive function or milk yield in any of the studies. The predicted 305-d milk yield (averages of least-squares means across treatments) were: 9478, 7073, and 10,204 kg projected 305-d milk for experiments 1, 2, and 3, respectively. Percentages of cows pregnant at first service were 30, 16, and 24% in experiments 1, 2, and 3, respectively. Three studies were performed to test whether vitamin E improved development of cultured bovine embryos exposed to heat shock. Heat shock of 41 degrees C at the two-cell stage reduced development to the blastocyst stage, but culture with 100 microM vitamin E did not reduce effects of heat shock on impaired development. For example, 9 h at 41 degrees C reduced blastocyst development from 51.2 +/- 3.3% to 3.4 +/- 3.3% in the absence of vitamin E and from 54.0 +/- 3.3% to 5.2 +/- 3.3% in the presence of vitamin E. Development of morulae to the blastocyst stage was not compromised by culture at 41 degrees C for 9 h. Additionally, there was no overall effect of vitamin E on morula development. In conclusion, multiple injections of vitamin E and selenium at the administered levels did not improve postpartum fertility nor milk yield of lactating Holstein cows in three different herds, and there was no direct thermoprotective effect of vitamin E for cultured, heat-shocked embryos.

The accepted biological potencies of vitamin E (United States Phamacopeia, 1985) for 1 mg all-rac-alpha-tocopheryl acetate (synthetic form) is 1.00 IU and that of 1 mg (RRR)-alpha-tocopheryl acetate (natural form) is 1.36 IU. In the present study, a stable isotopic (2H) technique was employed to evaluate the bioavailability of natural v. synthetic forms of vitamin E and to determine whether the potency of the forms is the stated relationship of 1.36:1.00 (RRR)-alpha-tocopheryl acetate:all-rac-alpha-tocopheryl acetate. Sixty female in-bred guinea pigs received either 40 or 80 mg vitamin E/kg diet with equal levels of (RRR)-alpha-tocopheryl acetate and all-rac-alpha-tocopheryl acetate throughout gestation and lactation. At late-term pregnancy (day 50 or 60) and during early lactation, dams and their corresponding fetuses or neonates were killed and various tissues collected for subsequent alpha-tocopherol analysis. Vitamin E analysis of fetal and neonatal tissues indicated a substantial transfer of 2H-labelled alpha-tocopherol across the placenta and through the mammary gland. Total alpha-tocopherol concentrations were significantly influenced by tissue type and dose level, but not by stage of gestation or lactation. The relative bioavailability (d3:d6) across fetal and neonatal tissues was on average 1.81:1.00, with a range from 1.62:1.00 to 2.01:1.00. Maternal tissues had a mean ratio of 1.77:1.00. A higher relative bioavailability (P

The objective of this study was to evaluate the rate and extent of Cu repletion in Holstein heifers using two Cu sources (organic and inorganic) at two levels (15 and 30 mg/kg). An additional repletion treatment included a Cu oxide bolus. Heifers (n = 50) were individually fed a total mixed ration fortified with S and Mo at 0.40%, and 15 mg/kg of dry matter of the total diet, respectively. After 111 d of depletion, heifers were stratified by liver Cu concentration and randomly allotted to one of five repletion treatments. Four treatments consisted of feed sources of Cu (feed-Cu), 1) CuSO4 at 15 mg/kg; 2) CuSO4 at 30 mg/kg; 3) Availa-Cu at 15 mg/kg; and 4) Availa-Cu at 30 mg/kg. Availa-Cu is an organic Cu source that produces a Cu-amino acid complex. A fifth treatment, consisting of an intraruminal bolus (IB), provided a single dose of 25 g of CuO needles. Repletion treatments were delivered in the same total mixed ration without supplemental S and Mo. Copper status was assessed in blood and liver samples collected on 14-d intervals for 70 d. Irrespective of treatment, all heifers increased in body weight during the repletion period. Liver Cu increased in each feed-Cu treatment over time. Heifers treated with an IB reached a peak in liver Cu concentration (165.5 mg/kg) on d 28. Mean liver Cu concentrations were higher in heifers receiving 30 mg/kg of Cu compared with heifers receiving 15 mg/kg of Cu. Red blood cell superoxide dismutase (SOD) activity was higher (P < 0.001) in heifers receiving CuSO4 than Availa-Cu (0.98 vs 0.87 U). Also, SOD activity was higher when heifers were supplemented with 30 vs 15 mg/kg Cu (0.98 vs 0.87 U). Heifers receiving the Cu IB had higher SOD activity than heifers receiving feed-Cu sources (1.03 vs 0.92 U). Plasma ceruloplasmin concentration was higher (P < 0.001) in IB-treated heifers vs. other treatments. No differences in plasma ceruloplasmin were detected for feed-Cu source or level. These results indicate that all Cu sources evaluated in this study elevated Cu status of depleted heifers, particularly when provided at higher dietary levels.

The effects of feeding whole cottonseed (WCS) and bovine somatotropin (bST) administration on hematological responses and plasma alpha-tocopherol concentrations of lactating dairy cattle were examined. After parturition, multi and primiparous Holstein cows (n = 159) were assigned randomly to a 2 x 2 factorial arrangement of treatments consisting of (0 or 15% WCS and 0 or 208 mg of bST injected every 2 wk starting within 7 d after calving. Blood samples were collected from a subset group of 64 cows at 14, 28, 42, and 56 d postpartum. Blood was collected from all cows (n = 159) at 75, 96 and 120 d postpartum. Blood samples were analyzed for alpha-tocopherol and total and (+)- and (-)-gossypol in plasma. Erythrocyte osmotic fragility, hemoglobin and hematocrit also were determined in blood. The mean concentrations of alpha-Tocopherol, total, and (+)- and (-)-gossypol were higher in cows fed WCS regardless of bST administration and plateaued by d 75 postpartum. Hematocrit and hemoglobin concentrations were not affected by treatments. Erythrocyte osmotic fragility was higher in cows fed WCS, but the increase was attenuated when bST was injected (diet x bST interaction). No clinical signs of gossypol toxicity were observed in the cows consuming the WCS.

To assess the impact of S fertilization on bahiagrass (Paspalum notatum) quality and Cu metabolism in cattle, two studies were conducted during the summer grazing season (1999 and 2000). Pasture replicates (16.2 ha; n = 2/treatment) received the same fertilizer treatment in each growing season, consisting of 1) 67 kg N/ha from ammonium sulfate (AS), 2) 67 kg N/ha from ammonium nitrate (AN), and 3) control (no fertilizer; C). Forage sampling was conducted at 28-d intervals following fertilization by the collection of whole plants (four samples/pasture) in randomly distributed 1-m2 grazing exclusion cages and analyzed for CP, in vitro organic matter digestibility, S, P, Ca, K, Mg, Na, Fe, Al, Mn, Cu, and Zn. To determine the effect of fertilizer treatment on liver trace mineral concentrations in grazing cattle, random liver tissue samples were collected (n = 12; four/treatment) at the start and end of the study period in 2000. Ammonium sulfate fertilization increased (P < 0.001) forage S concentration in both years. Plant tissue N concentrations were increased by N fertilization, regardless of source, in 2000, but not in 1999. Cows grazing AS pastures had lower (P < 0.05) liver Cu concentrations at the end of the study period in 2000 compared to AN and C. In Exp. 2, 37 Cu-deficient heifers grazing AS fertilized pastures were obtained from the same location and allocated to one of two treatments, consisting of supplements providing 123 mg/d of either inorganic (Cu sulfate; n = 12) or organic (Availa-Cu; n = 15) Cu. Treatments were delivered for 83 d. Liver Cu increased over time in all heifers regardless of treatment; however, heifers supplemented with Availa-Cu tended (P = 0.09) to have higher mean liver Cu concentrations than those receiving Cu sulfate. The results of these studies indicate that AS fertilization of bahiagrass increases forage S concentrations. When provided free-choice access to a complete salt-based trace mineral supplement, cows grazing AS-fertilized pastures had lower liver Cu concentrations than cows grazing pastures fertilized with AN; upon removal from high-S pastures, cattle were able to respond to Cu supplementation.

Superovulated Hereford-Angus crossbred heifers (average 397 kg BW) were used to test the effect of feeding cottonseed meal (gossypol) and vitamin E on embryo quality and ovarian characteristics. Twenty-four heifers were assigned randomly to four treatments with six heifers per treatment. Treatments were the following dietary supplements: 1) SBM (soybean meal + 30 IU vitamin E/kg of diet DM); 2) SBM+E (soybean meal + 4,000 IU vitamin E x animal(-1) x d(-1)); 3) CSM (cottonseed meal + 30 IU vitamin E/kg of diet DM); and 4) CSM+E (cottonseed meal + 4,000 IU vitamin E x animal(-1) x d(-1)). Supplements based on cottonseed meal provided 43.5 g of total gossypol/d (37% negative isomer (-) and 63% positive isomer (+)). Blood samples were collected at the start of the experiment and every 3 wk thereafter up to 12 wk. Plasma a-tocopherol (alpha-T) concentration was affected by treatments (P < 0.05). Heifers supplemented with cottonseed meal had greater (P < 0.05) alpha-T concentration in plasma than heifers supplemented with soybean meal at each concentration of vitamin E. Supplementation at 4,000 IU vitamin E x animal(-1) d(-1) increased (P < 0.05) the concentration of a-T in plasma. Weight gain, hemoglobin and hematocrit were not affected by treatment. Erythrocyte osmotic fragility (EOF) increased (P < 0.05) in cottonseed meal-fed animals; however, EOF was lowered (P < 0.05) with vitamin E supplementation. Heifers fed CSM and CSM+E supplements had greater (P < 0.01) concentrations of (-)-, (+)-, and total-gossypol in plasma, corpora lutea (CL), liver, and endometrium than heifers fed SBM and SBM+E supplements. Tissue alpha-T concentration increased with increased dietary supplemental vitamin E, particularly in great amounts in the CL. Because there was no adverse effect of gossypol on superovulation response or embryo development despite concentrations of gossypol in endometrium that are toxic to embryos, it is likely that systems exist in the reproductive tract to limit gossypol toxicity.

An experiment was designed to assess the mineral status of 60 Angus yearling beef steers grazing bahiagrass pastures fertilized with large amounts of biosolids from three sources: Baltimore, MD; Tampa, FL; and Largo, FL. Biosolids were classified as exceptional quality and thus had no regulatory restrictions on loading rate. They differed primarily in concentration of Mo (12 to 56 mg/kg of DM). Residual treatments (biosolids applied only the previous year) for Baltimore biosolids were applied at 22.4 and 44.8 t/ha, and Tampa biosolids were either 16.8 or 33.6 t/ ha. The reapplied treatments (applied in consecutive years) for both Baltimore and Tampa sludges were applied at 22.4, 44.8, 16.8 , and 33.6 t/ha, respectively. The two Largo biosolids treatments were either 56 or 112 t/ha and were applied only in the 2nd yr. Liver biopsies and blood samples were collected on d 1, 95, and 180. Liver and plasma were analyzed for minerals and blood was analyzed for hemoglobin, hematocrit, and superoxide dismutase of polymorphonuclear neutrophils. Experimental animals were generally adequate in macromineral status and Co, Fe, and Mn throughout the experiment. Copper deficiency was evident based on the clinical signs of hair coat discoloration, very low plasma Cu at d 95, and the continuous decline in liver Cu over 180 d. A sharp decline in plasma Cu was observed for all treatments from d 1 to 95, after which Cu concentrations rebounded to normal concentrations (> 0.65 microg/mL) by d 180. Liver Mo was well below concentrations indicating toxicity (> 5.0 mg/kg). The steep decline in liver Cu over the first 95 d reflects the dietary Cu deficiency and the possibility of high forage S (0.26 to 0.52%) interfering with Cu metabolism. Biosolids application to bahiagrass pastures was not detrimental to mineral status except for declining Cu stores; however, the controls likewise declined, but to a lesser degree.

The USEPA standards (40 CFR Part 503) for the use or disposal of sewage sludge (biosolids) derived risk-based numerical values for Mo for the biosolids --> land --> plant --> animal pathway (Pathway 6). Following legal challenge, most Mo numerical standards were withdrawn, pending additional field-generated data using modern biosolids (Mo concentrations <75 mg kg(-1) and a reassessment of this pathway. This paper presents a reevaluation of biosolids Mo data, refinement of the risk assessment algorithms, and a reassessment of Mo-induced hypocuprosis from land application of biosolids. Forage Mo uptake coefficients (UC) are derived from field studies, many of which used modern biosolids applied to numerous soil types, with varying soil pH values, and supporting various crops. Typical cattle diet scenarios are used to calculate a diet-weighted UC value that realistically represents forage Mo exposure to cattle. Recent biosolids use data are employed to estimate the fraction of animal forage (FC) likely to be affected by biosolids applications nationally. Field data are used to estimate long-term Mo leaching and a leaching correction factor (LC) is used to adjust cumulative biosolids application limits. The modified UC and new FC and LC factors are used in a new algorithm to calculate biosolids Mo Pathway 6 risk. The resulting numerical standards for Mo are cumulative limit (RPc)=40 kg Mo ha(-1), and alternate pollutant limit (APL) = 40 mg Mo kg(-1) We regard the modifications to algorithms and parameters and calculations as conservative, and believe that the risk of Mo-induced hypocuprosis from biosolids Mo is small. Providing adequate Cu mineral supplements, standard procedure in proper herd management, would augment the conservatism of the new risk assessment.

To test the hypothesis that fledging wading birds would be more at risk from mercury toxicosis than younger nestlings, captive great egret nestlings were maintained as controls or were dosed from 1- to 14-wk-old with 0.5 or 5 mg methylmercury chloride/kg wet weight in fish. Birds dosed with 5 mg/kg suffered from subacute toxicosis at wk 10-12. Growing feather concentrations were the most closely correlated with cumulative mercury consumed per weight. Blood concentrations of mercury increased more rapidly after 9 wk in all groups when feathers stopped growing. Total mercury accumulated in tissues in concentrations in the following order: growing scapular feathers > powderdown > mature scapular feathers > liver > kidney > blood > muscle > pancreas > brain > bile > fat > eye. The proportion of total mercury that was methylated depended upon tissue type and dose group. Selenium accumulated in liver in direct proportion to liver mercury concentrations. After wk 9, appetite and weight index (weight/bill length) declined significantly in both dosed groups. At current exposure levels in the Everglades (Florida, USA) mercury deposited in rapidly growing feathers may protect nestlings from adverse effects on growth until feathers cease growing.

Angus x Hereford heifers (n = 50) were randomly assigned to bahiagrass pastures treated with biosolids varying in mineral content and evaluated for mineral status, with special attention to Cu. Biosolids and NH4NO3 were all applied at the rate of either 179 kg N/ha (X) or twice this (2X). Fertilizer was applied to .81-ha pastures for the following treatments: 1) Baltimore biosolids (1X = 179 kg N/ha); 2) Baltimore biosolids (2X = 358 kg N/ha); 3) Tampa biosolids (1X = 179 kg N/ha); 4) Tampa biosolids (2X = 358 kg N/ha); or 5) control NH4NO3 (1X = 179 kg N/ha) applied at two times. Pastures were divided into five blocks with each treatment represented once in each block. Copper loads varied from 8.8 to 42.2 kg/ha, and Mo loads varied from .27 to 1.11 kg/ha. Heifers (two per pasture) grazed their assigned pastures exclusively for 176 d. Liver biopsies were taken from all animals at d 1, 99, and 176, and blood samples on d 1, 50, 99, 135, and 176. Liver and plasma were analyzed for selected mineral contents, and blood was analyzed for hemoglobin and hematocrit. Experimental animals were generally low in mineral status when assigned to pastures and deficient in Se and P. By d 50, plasma Ca, Mg, Se, P, and Zn were adequate for all treatments. Plasma Cu declined (P < .03) for all treatments from d 50 to 176. Plasma Cu reflected depleted liver Cu storage, with the two Tampa and highest Baltimore treatment means lower in plasma Cu than the control at 176 d. Liver Fe concentrations were adequate for all treatments, and Mo concentrations (< 2.18 mg/kg) did not approach levels indicative of toxicity. Liver Cu declined (P < .05) with time for all treatments. By d 99, animals receiving the two Baltimore treatments and the lowest Tampa application rate had lower (P < .05) liver Cu than the control, and all treatments were lower at 176 d. The decline of animal Cu status (liver and plasma) reflects the low Cu status of bahiagrass and the possibility of high forage S (.30 to .47%) interfering with Cu metabolism. Forage Mo was low but was slightly higher in biosolids-treated pastures. High levels of biosolids applications to bahiagrass pastures were not detrimental to mineral status except Cu, which had a tendency to decline in plasma and for all biosolids treatments declined in liver.

The effects of feeding different sources and quantities of Cu to heifers were evaluated in a 211-d experiment. Forty crossbred predominantly Brahman x Hereford heifers averaging 13.5 mo of age and 301 kg were initially depleted of Cu. The depletion diet was fed for 70 d and consisted of low Cu and high antagonist minerals, Fe, S, and Mo at 1000 mg/kg, 0.5%, and 5 mg/kg (dry basis), respectively. On d 71, heifers continued to receive the antagonistic minerals and were allotted equally to five Cu treatments: 1) control, no additional Cu source; 2) 8 mg of Cu/kg from CuSO4; 3) 16 mg of Cu/kg from CuSO4; 4) 8 mg of Cu/kg from Cu lysine; and 5) 16 mg of Cu/kg from Cu lysine. When no notable change in concentration of Cu in the liver was observed, d 169, a second diet was formulated. The heifers were fed the same Cu treatments, but S and Mo were removed and Fe was lowered to 50 mg/kg. This diet was then fed for the final 42 d of the experiment. In addition to performance, concentrations of Cu, Fe, and Zn in the plasma and liver, plasma ceruloplasmin, hemoglobin, superoxide dismutase (SOD) activity of neutrophils and lymphocytes, and a cell mediated immune response (phytohemagglutinin-P, PHA) were measured. Heifers in this study had increased growth over time, but there were no treatment differences for growth and average daily gain. Liver and plasma Cu concentrations were not greatly influenced by different supplemental Cu sources. However, compared with other treatments, Cu lysine (16 mg/kg) increased liver Cu in cattle that were deficient and tended to increase plasma Cu in animals that were marginally deficient in Cu. Iron concentrations decreased over time in liver and plasma, but there was no difference in Fe and Zn concentrations in liver and plasma among treatments. Differences in ceruloplasmin and hemoglobin concentrations were significant over time but not among treatments. The SOD activity in neutrophils did not change over time, but SOD activity of lymphocytes increased over time. For the PHA immune response test, there was no effect of time or a time by treatment interaction. These data suggest that all Cu sources were available, but Cu at 16 mg/kg from Cu lysine was more beneficial than were other sources and particularly for heifers with low Cu status.

Packages (n = 660) of clod, strip loin, tenderloin, bottom round, eye-of-round, and top round steaks, as well as ground beef, from beef cattle fed diets supplemented with vitamin E (500 IU/d for 100 d preharvest) were compared with packages of products derived from carcasses of beef cattle fed control diets to determine the duration of acceptable muscle color during simulated retail display. In addition, the effect of storage before steak fabrication, simulating distribution time, on the acceptability of each treatment and each cut during retail display was investigated. Dietary supplementation of animals with vitamin E increased muscle alpha-tocopherol concentrations (P < .05) in all cuts. The acceptable retail display time of ground beef from vitamin E-supplemented cattle was longer (P < .05) compared to ground beef from unsupplemented cattle by 10.2, 15.6, and 17.6 h following 7, 14, and 21 d of storage in chub packages prior to final grinding and retail display, respectively. However, length of storage in a vacuum package before retail display did not have a consistent effect on retail case life of steaks. Product drip loss during retail display was not affected by storage time or vitamin E treatment. The trained panel color score during retail display of high vitamin E strip loin, bottom round, inside round, and eye-of-round steaks remained acceptable longer (P < .05) by 11.5, 25.2, 8.4, and 29.4 h, respectively, than that of control steaks. The results demonstrated that vitamin E supplementation of cattle feed can be used as a management tool to reduce the economic losses associated with beef muscle color deterioration during retail display of products.

Male Holstein calves were used to test the effect of feeding 400 mg of free gossypol/kg of diet and to determine whether vitamin E could counteract gossypol toxicity. Fifty-two calves were allotted to treatments as follows: 1) soybean meal-based starter; 2) cottonseed meal-based starter; 3) cottonseed meal-based starter + 2000 IU of vitamin E/d per calf, and 4) cottonseed meal-based starter + 4000 IU of vitamin E/d per calf. Vitamin E supplementation (treatments 3 and 4) improved weight gain and feed intake over calves on treatment 1. Gossypol concentrations in plasma were higher in calves on treatments 2, 3, and 4 than in calves on treatment 1; however, no differences were observed among animals receiving the three cottonseed meal diets. Hemoglobin and hematocrit were decreased in calves receiving treatment 2, and vitamin E supplementation counteracted this effect (treatments 3 and 4). Plasma alpha-tocopherol concentrations were not affected by gossypol intake and followed the vitamin E supplementation pattern During the experimental period, 10 calves died, six from treatment 2 and two each from treatments 3 and 4. Necropsy findings from 4 of 10 calves were suggestive of gossypol toxicity. Histopathological examination revealed centrilobular necrosis in the liver and atrophy and vacuolation of cardiocytes. Feeding cottonseed meal caused death of some calves with gossypol related toxicity signs, but did not decrease plasma alpha-tocopherol; however, vitamin E supplementation increased performance and may have conferred some protection against gossypol toxicity.

An experiment was conducted to determine the effects of long-term feeding of cottonseed meal on the reproductive traits of Holstein bulls. Holstein bulls approximately 6 mo of age were placed on the following treatments: 1) soybean meal + corn (CON); 2) cottonseed meal + corn (GOS); and 3) cottonseed meal + 4,000 IU vitamin E x bull(-1) x d(-1) (G+4E). The GOS and G+4E diets were formulated to supply 14 mg of free gossypol x kg(-1) BW x d(-1). These bulls had been in a previous experiment that evaluated the effects of feeding the same type of diets, but from 2 wk to 6 mo. of age. Percentage of motility, percentage of normal and live sperm, and daily sperm production were less (P<.05) in the GOS than in the other two treatments. Percentages of primary abnormalities and abnormal midpieces were greater (P<.05) in the GOS group than in the other two groups. At 12 and 16 mo. of age, bulls were given two assessments for sex drive traits. Bulls that received gossypol exhibited less sexual activity (P<.05) at the first test than bulls in other treatments. Vitamin E supplementation in bulls that received gossypol improved the number of mounts in the first test and the time to first service in the second test. There was a trend of gossypol to decrease and vitamin E to improve libido score. The results of the GOS first libido test may indicate lack of sexual maturity, which agrees with sperm production data. At the time of first test (12 mo. of age), none of GOS, two of CON, and six of G+4E bulls had reached puberty on the basis of experimental protocol. Long-term feeding of gossypol to Holstein bulls negatively affected some reproductive traits; however, vitamin E supplementation countered these adverse effects and even improved these traits.

We conducted an experiment for 112 d with yearling beef heifers to evaluate the effects of cottonseed meal (CSM) fed with various concentrations of vitamin E on hematological and tissue components. Heifers were assigned randomly to four treatments, with eight heifers per treatment. The treatments consisted of the following dietary supplements: 1) CON, based on soybean meal with 30 IU vitamin E/kg; 2) GOS, based on CSM with 30 IU vitamin E/kg; 3) G+2E, based on CSM with 2,000 IU vitamin E x animal(-1) x d(-1); and 4) G+4E, based on CSM with 4,000 IU vitamin E x animal(-1) x d(-1). Supplements based on CSM provided 4.5 g of free and 50.5 g of total gossypol x animal(-1) x d(-1). The total gossypol present in the supplements was 29.1% of the negative isomer (-) and 70.9% of the positive isomer (+). Blood samples were collected at the start of the experiment and every 2 wk thereafter up to 16 wk. There was a time x treatment interaction (P<.01) for plasma alpha-tocopherol ( alpha-T) concentration; however, feeding gossypol did not decrease plasma alpha-T. Weight gain, retinol palmitate, retinol, beta-carotene (beta-C), hemoglobin, and hematocrit were not affected by treatment. Erythrocyte osmotic fragility (EOF) increased (P<.05) in gossypol-fed animals; however, vitamin E supplementation lowered EOF (P<.05). Heifers fed the supplements GOS, G+2E, and G+4E had greater (P<.01) plasma (-)-, (+)-, and total gossypol than heifers fed CON from Collection 2 to the end of the experiment. There was a treatment effect (P<.05) on vitamin E and gossypol concentrations in different tissues, with no effect (P>.05) for trace minerals (Cu, Zn, Fe, and Se). Vitamin E concentration in tissue increased with increased dietary supplementation of vitamin E. In heart and neck muscle, (-)-gossypol was greater (P<.05) than (+)-gossypol, but the reverse was true for liver. Gossypol decreased in vitro lipid peroxidation of liver homogenate in tissues. Gossypol deposition in tissue was liver > heart > muscle. In summary, gossypol from CSM did not decrease concentrations of antioxidant vitamins, including alpha-T, vitamin A, and beta-C, or have any detrimental effect on performance of beef heifers.

Long-term effects of the inclusion of cottonseed meal in the diet on hematological and tissue parameters of Holstein bulls were investigated. Twenty-four Holstein bulls that were approximately 6 mo of age received the following treatments for 10 mo: 1) soybean meal plus 30 IU of vitamin E/kg, 2) cottonseed meal plus 30 IU of vitamin E/kg, and 3) cottonseed meal plus 4000 IU of vitamin E/d per bull. Treatments 2 and 3 were formulated to supply 14 mg of free gossypol/kg of body weight per d. Average daily gain, total gain, and final body weights were not affected by treatment. The osmotic fragility of erythrocytes was greater during all collection periods for bulls on treatments 2 and 3 than for bulls on treatment 1. The inclusion of 4000 IU of vitamin E/d per bull did not reduce the increase in the osmotic fragility of erythrocytes that was caused by gossypol. Bulls on treatment 3 had higher plasma alpha-tocopherol concentrations than did bulls on treatments 1 and 2. Vitamin E supplementation did not affect gossypol concentrations in plasma or tissue. The highest gossypol concentrations were found in the liver followed by the heart and testis. In vitro lipid peroxidation of tissue indicated that gossypol acts as an antioxidant in lipid peroxidation systems, and its role as an antioxidant may be dependent on dose or tissue. Cottonseed meal in the diets of bulls did not affect growth or vitamin E status.

Experiments tested whether supplemental antioxidants improved fertility. To test effects of beta-carotene, cows in a hot environment were injected with prostaglandin F2 alpha (PGF2 alpha) and were given 3 injections, i.m., of 800 mg beta-carotene or saline at Days -6 and -3 before the anticipated date of insemination and at insemination (n = 37-41 inseminated cows/group). There was no effect of beta-carotene on the proportion of cows detected in estrus following PGF2 alpha, timing of estrus after PGF2 alpha injection or pregnancy rate in inseminated cows. In a second trial, cows in a temperate climate received intramuscular injections of vitamin E (500 mg) and selenium (50 mg) at 30 d post partum (n = 97) or were untreated controls (n = 89). Treatment did not affect interval from calving to first insemination or the proportion of cows pregnant at first service, but it increased the pregnancy rate at second service (69.8 vs 52.1%; P = 0.07) and reduced services per conception (1.7 vs 2.0; P < 0.05) and interval from calving to conception (84.6 vs 98.1; P < 0.05). Thus, injection of vitamin E and selenium increased fertility in cattle that did not become pregnant at first service.

Hereford-Angus crossbred heifers were fed a cottonseed meal-based diet containing gossypol (14 mg free gossypol x kg body wt(-1) x d(-1); CSM), a soybean meal-based diet (SBM), or alpha-tocopherol-supplemented diets (4,036 IU vitamin E x heifer(-1) x d(-1) for 90 d; CSM+E and SBM+E). The effects of diet on color stability and aerobic metmyoglobin reducing ability of beef longissimus lumborum (LL) and psoas major (PM) were evaluated. The CSM containing gossypol did not affect alpha-tocopherol concentration, a* value, or hue angle value of beef muscles obtained from control or vitamin E-supplemented cattle compared to their SBM counterparts. Vitamin E supplementation increased endogenous alpha-tocopherol concentrations and color stability in LL and PM muscles compared with controls from either diet (P < .05). In the aerobic metmyoglobin reducing ability study, LL and PM muscles were stored in 1% O2:99% N2 (a pigment-oxidizing atmosphere) for 48 h and subsequently stored aerobically for an additional 48 h. Within the LL, alpha-tocopherol supplementation delayed metmyoglobin formation in LL exposed to 1% O2 (P < .05). Within the PM, no differences in metmyoglobin formation were found between controls and vitamin E treatments in SBM or CSM diets. Relative aerobic metmyoglobin reduction was the same (P > .05) in LL and PM muscles within SBM or CSM diets for control and vitamin E treatments. Alpha-tocopherol did not seem to affect metmyoglobin aerobic reducing ability in LL and PM muscles.

Follicular growth, lifespan of the corpus luteum, and antioxidant status of lactating Holsteins that experienced heat stress were monitored. Eleven multiparous cows, 60 to 110 d in milk, were maintained from 0800 to 1800 h daily in environmental chambers from d 11 to 21 of the estrous cycle. Cows were randomly assigned to a heat stress (mean dry bulb temperature peaked at 38.3 degrees C) or control treatment (mean dry bulb temperatures varied from 20.8 to 25.6 degrees C). Rectal temperature and respiration rates of heat-stressed cows were higher at 1600 h than were those of control cows. The length of the estrous cycle and the interval from estrus until luteolysis were not different between treatments. Two of 6 control cows and 1 of 5 heat-stressed cows had extended cycles (> 24 d). Heat-stressed cows had more class 1 (2 to 5 mm) follicles from d 11 to 15 of the estrous cycle. Numbers of class 2 (6 to 9 mm) and class 3 (> or = 9 mm) follicles were similar between treatments. Plasma progesterone concentrations were higher for heat-stressed cows until d 19 of the estrous cycle. Treatment did not affect concentrations of alpha-tocopherol, beta-carotene, retinol, retinyl palmitate, or total protein in plasma or concentrations of malondialdehyde in muscle. In conclusion, heat stress did not extend luteal function or the length of the estrous cycle of lactating Holstein cows but did affect follicular growth and progesterone concentrations in plasma. Heat stress did not appear to increase lipid peroxidation or decrease lipid-soluble antioxidant concentrations in blood.

In three experiments, we tested the efficacy of timed artificial insemination (AI) and beta-carotene supplementation for improvement of reproduction and milk yield. Experiments 1 and 2 were conducted during hot months, and Experiment 3 was conducted during cooler months. Cows were fed rations supplemented with beta-carotene at 0 or 400 mg/d per cow for > or = 15 d before the first AI. Cows were inseminated at each observed estrus after 70 d (Experiment 1) or at 50 d postpartum (Experiments 2 and 3) or were included in a timed AI program [d 0 (i.e., approximately 40 or 60 d postpartum), 8 micrograms of GnRH agonist; d 7, 25 mg of PGF2 alpha; d 9, 8 micrograms of GnRH agonist; d 10, AI] for first breeding. Pregnancy rate at first AI was similar among groups, but the percentage of cows that were pregnant by 90 d postpartum was greater for cows in the timed AI group in Experiments 1 (16.6% vs. 9.8%) and 2 (34.3% vs. 14.3%) but not in Experiment 3 (24.1% vs. 28.7%). Overall, beta-carotene had no effect on reproductive function. For cows fed supplemental beta-carotene for > or = 90 d, however, pregnancy rate at 120 d postpartum was increased in Experiment 1 (35.4% vs. 21.1%). In all experiments, beta-carotene increased cumulative milk yield on the last test day by 6 to 11%. In conclusion, timed AI can improve pregnancy rates during periods of heat stress. Supplemental beta-carotene may increase pregnancy rates for cows in the summer and can increase milk yield.

We conducted a 4 x 3 factorial experiment with finishing pigs for 6 wk to evaluate effects of dietary canola oil and vitamin E on vitamin E status and liver fatty acid profile. Treatments consisted of four supplemental levels of vitamin E (0, 50, 125, and 200 mg/kg) and three of canola oil (0, 5, and 10% of the diet). Serum was collected each week and tissue samples at d 42. Dietary canola oil (P = .02) and vitamin E (P < .001) increased serum alpha-tocopherol. Serum alpha-tocopherol reached a plateau at d 35 of vitamin E and canola oil supplementation. An interaction was observed between canola oil and vitamin E (P = .02) for liver alpha-tocopherol. Liver alpha-tocopherol was greater in pigs fed diets with 10% canola oil and supplemented with 125 or 200 mg/kg of vitamin E than in pigs fed diets with 0 and 5% canola oil. An interaction also occurred between canola oil and vitamin E (P = .01) for alpha-tocopherol in the gluteus medius and obliquus capitis caudalis muscles. A greater magnitude of increase in muscle alpha-tocopherol was observed in pigs fed diets with no canola oil than in pigs fed diets with 5 and 10% canola oil. Highest alpha-tocopherol was in liver, followed by obliquus capitis caudalis and then gluteus medius. Inclusion of 5 or 10% dietary canola oil decreased the amount of saturated fatty acids by 4.1 and 13.5%, increased monounsaturated fatty acids by 10.9 and 39.3%, respectively, and had no effect (P > .10) on total polyunsaturated fatty acids. Canola oil increased linoleic acid [18:2(n-6)] (quadratic, P = .05) and linolenic acid [18:3(n-3)] (linear, P < .001) while decreasing arachidonic acid [20:4(n-6)] and docosadienoic acid (20:2) linearly (P < .001 and P = .02, respectively). Dietary canola oil and vitamin E increased serum and tissue alpha-tocopherol; canola oil increased monounsaturated and decreased saturated fatty acids in liver.

Gossypol (50 and 100 micrograms/ml) decreased the percentage of sperm that completed the swim-up procedure. This effect was not blocked by glutathione monoethyl ester. Cleavage rates were not different between oocytes inseminated with gossypol-treated spermatozoa (10 or 50 micrograms/ml) and oocytes inseminated with control spermatozoa. Development to the blastocyst stage at Day 7 after insemination was reduced when spermatozoa treated with 50 micrograms/ml gossypol were used for fertilization. Gossypol toxicity was evident in cows fed cottonseed meal because erythrocyte fragility was greater than for control cows. However, there were no differences between cottonseed meal and control groups in number of oocytes collected per cow, cleavage rate after in vitro maturation and fertilization, or the proportion of oocytes or embryos that developed to blastocysts. Similarly, exposure of oocytes to 2.5-10 micrograms/ml gossypol during in vitro maturation did not affect cleavage rates or subsequent development. In contrast, addition of 10 micrograms/ml gossypol to embryos reduced cleavage rate. Moreover, development of cleaved embryos was reduced by culture with 5 or 10 micrograms/ml gossypol and tended to be reduced by 2.5 micrograms/ml gossypol. In conclusion, bovine gametes are resistant to gossypol at concentrations similar to those in blood of cows fed cottonseed meal. In contrast, the developing embryo is sensitive to gossypol.

A 12-week experiment was conducted to compare supplemental ZnMet, ZnSO4, and ZnO on Zn, Cu and metallothionein (MT) concentrations in various fluids and tissues of 32 yearling cattle. Supplemental Zn (360 mg per day) was fed for four weeks, withdrawn for four weeks, and then resumed for another four weeks. Mineral (Zn and Cu) concentrations were determined in serum, liver, pancreas, kidney, bone, bone marrow (metacarpus), hair, hoof and neck muscle (sterno mandibularis), and Zn only in erythrocytes, skin and cornea. Metallothionein levels were determined in liver, pancreas and kidney. There were no treatment differences (p > 0.05) in serum or erythrocyte Zn content for all days of collection. Serum Cu concentrations tended to decrease with all treatments. There were no treatment differences (p > 0.05) in Zn and Cu tissue concentrations and liver, kidney and pancreas MT concentrations. Tissue Cu concentrations did not drop in the supplemented treatments when compared to controls. At adequate levels of dietary Zn, bioavailability of supplemental Zn sources may be less important than under conditions of limited dietary Zn or if very high levels of supplemental Zn are fed.

A study was conducted to compare bioavailability, interactions and retention of different sources of Zn and Cu fed to rats. Sixty-three male CD rats were fed individually a purified diet and deionized water ad libitum. The nine treatments included were all combinations of three Zn (ZnMet, ZnLys, ZnSO4) and three Cu (CuLys, CuSO4, CuO) sources added to the basal diet at 30 mg/kg of Zn and 6 mg/kg of Cu forming a 3' 3 factorial experiment. After the four-week supplementation phase, four randomly selected rats from each treatment were sacrificed (Phase 1). The remaining rats were fed the purified, unsupplemented diet for an additional week (Phase 2) and then sacrificed. Mineral (Zn and Cu) concentrations were determined in plasma, liver, kidney, bone and muscle, and metallothionein (MT) content was determined in liver and kidney. Plasma Cu concentrations were lower (p < 0.05) for CuO-than CuSO4- and CuLys-supplemented rats. Bone Zn concentrations were higher (p < 0.05) for CuLys-than for CuO-supplemented rats. In all tissues where Cu was measured, CuO was the lowest (p < 0.05) available source of Cu. Furthermore, in muscle, CuSO4-supplemented rats had higher (p < 0.05) Cu concentrations than CuLys-supplemented rats. Kidney MT concentrations followed the same pattern as Cu concentrations, with CuO-fed rats having the lowest (p < 0.05) MT concentrations. Plasma Cu concentrations of depleted rats were lower (p < 0.05) for CuO-than CuLys-supplemented rats. Kidney Zn concentrations were lower (p < 0.05) for CuSO4-than for CuO-supplemented rats after depletion. In liver, CuO supplemented rats had the lowest (p < 0.05) Cu concentration. Copper oxide was less available than CuLys and CuSO4 when added in adequate dietary levels. However, organic (ZnMet and ZnLys) and inorganic (ZnSO4) sources of Zn were similar.

Effects of four dietary levels of DL-alpha-tocopheryl acetate (0, 500, 1,500, and 3,000 IU.animal-1.d-1) on serum, red blood cell (RBC), and tissue alpha-tocopherol concentrations were investigated in 32 yearling cattle during an 84-d trial. Supplemental vitamin E was fed for 28 d, withdrawn for 28 d, and then resumed for another 28 d. Blood was collected on d 1 before treatment administration, d 3, and biweekly thereafter. Serum alpha-tocopherol increased rapidly from pretreatment values (1.8 micrograms/mL) with linear (P < .05) treatment effects on d 3 and 14 and cubic treatment effects on d 28. Upon withdrawal of vitamin E supplementation, serum tocopherol concentrations declined and again increased rapidly and linearly by d 84 after supplementation was resumed. Concentration of alpha-tocopherol in RBC did not respond appreciably to supplemental vitamin E. There were no vitamin E treatment effects on blood lipid fractions (cholesterol and triglycerides). When serum tocopherol was expressed relative to the sum of cholesterol and triglycerides, response to vitamin E intake followed similar trends as serum alpha-tocopherol. The relationship between serum alpha-tocopherol concentrations or serum tocopherol:cholesterol plus triglycerides ratio and vitamin E intake was linear (P < .05) for d 14, 28, and 84 and linear with liver for d 84. Serum and liver tocopherol reflected vitamin E intake and can be used reliably to estimate vitamin E status in young cattle.

A study was conducted to compare supplemental Zn lysine (ZnLys), Zn methionine (ZnMet), ZnSO4, and ZnO on Zn, Cu, and metallothionein (MT) concentrations in various fluids and tissues of 40 wether lambs. Supplemental Zn (360 mg/kg) was fed for 3 wk, withdrawn for 4 wk, and then resumed for another week. Mineral (Zn and Cu) concentrations were determined in serum, liver, pancreas, kidney, bone, bone marrow, hoof, and leg muscle, and only Zn was determined in skin and cornea. Metallothionein concentration was determined in liver, pancreas, and kidney. By d 49 serum Zn had increased less (P < .05) for controls than for all lambs except those fed ZnMet, and on d 55 it had increased more (P < .05) for ZnLys than for all but ZnSO4. There were no treatment effects in serum Cu concentration, but overall Cu concentration fell slightly for all treatments from d 0. The ZnLys-treated lambs had the highest (P < .05) Zn accumulation (581, 389, and 340 mg/kg) in kidney, liver, and pancreas, respectively. Both ZnSO4- and ZnMet-treated lambs had higher (P < .05) liver Zn concentrations (195 and 198 mg/kg, respectively) than the control lambs (127 mg/kg). Mean Zn concentration of bone, bone marrow, cornea, skin, hoof, and muscle was not different (P > .05) for lambs among treatments. The ZnLys-treated lambs had the highest (P < .05) MT concentrations (79, 167, and 68 micrograms MT/g for liver, kidney, and pancreas, respectively). Mean muscle Cu concentration was highest (P < .05) for controls (10 mg/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

A study was conducted to evaluate the effects of high dietary vitamin A on vitamin E status and performance of growing-finishing pigs fed diets supplemented with varying levels of vitamin E. Treatments consisted of corn-soybean meal-based diets supplemented with retinyl acetate to provide 2,000 or 20,000 IU of vitamin A/kg of diet and with DL-alpha-tocopheryl acetate to provide 0, 15, or 150 IU of added vitamin E/kg in a 2 x 3 factorial arrangement. The trial involved 84 crossbred pigs (26 kg initial BW) allotted to pens of two pigs each (one gilt, one barrow). Serum was obtained from all pigs on d 0, 3, 7, 21, 35, 63, and 77 of the 83- or 90-d feeding period. Tissue samples (liver, leg, and neck muscle, backfat, and leaf fat) were collected from one pig (barrow) in each pen at the end of the feeding period. Average daily gain and gain:feed were .93 kg and .30, respectively, without treatment differences (P > .10). Serum alpha-tocopherol increased linearly (P < .01) by d 3 with increasing level of dietary vitamin E supplementation. High dietary vitamin A resulted in a small decrease (P < .01) in serum alpha-tocopherol on d 3, but serum alpha-tocopherol concentration was not affected (P > .10) on other days. Tissue alpha-tocopherol increased linearly (P < .001) as dietary vitamin E increased in all tissues examined. No consistent evidence was found to indicate that a high level of dietary vitamin A interfered with performance or with blood serum or tissue alpha-tocopherol concentrations in growing-finishing swine.

Samples of serum, liver, kidney, and heart were collected for selenium analysis from 174 white-tailed deer (Odocoileus virginianus) in southern Florida (USA), 1984 to 1988, to determine the selenium status of these animals. Deer were obtained from eight sites and classified by five age-class groups. For serum and the three tissues analyzed, selenium concentrations varied significantly (P < 0.001) among sites. Differences between years (P < 0.0004) were found for heart and kidney, age-class (P < 0.004) for kidney and season (P < 0.02) for liver. Low selenium concentrations were evident, in that 75% of all serum samples analyzed contained less than the critical concentration (< 0.06 ppm) by livestock standards, with 50% of serum samples less than 0.03 ppm, evidence of a severe deficiency. Likewise, tissue selenium concentrations (dry basis) were below critical livestock concentrations in 13% of the liver samples (< 0.25 ppm), 36% in kidney (< 3.0 ppm) and 19% in heart (< 0.15 ppm). Based on serum and tissue data, selenium dietary intake was low and may have been deficient for white-tailed deer in southern Florida.

Relative bioavailabilities of four chemical forms of vitamin E were evaluated when supplemented in diets of finishing swine for 28 d. Forty crossbred pigs (80 kg), individually penned, were divided equally among five treatments. Treatments consisted of corn soybean meal-based diets supplemented with DL-alpha-tocopherol, DL-alpha-tocopheryl acetate, D-alpha-tocopherol, or D-alpha-tocopheryl acetate. A treatment without vitamin E supplementation (negative control) served as the fifth treatment. Each compound was supplemented at 62 IU/kg of diet. Blood samples were collected on d 0, 1, 2, 7, 14, 21, and 28. On d 29, half the pigs were slaughtered to obtain tissue samples. Feed samples, taken from feeders, were also collected on d 0, 5, 14, and 21. All vitamin E forms fed increased (P < .01) serum alpha-tocopherol by d 2 and peaked by d 7. Serum alpha-tocopherol in pigs fed either acetate form remained elevated beyond d 7; serum alpha-tocopherol steadily declined and was lower (P < .01) on d 14, 21, and 28 in pigs fed either alcohol form compared with concentrations in the acetate-fed pigs. The decrease was probably a reflection of poor stability of the alcohol forms observed in the feed; the acetate forms were found to be stable in the feed over the 28-d study. Dietary supplementation of D-alpha-tocopheryl acetate resulted in the highest serum alpha-tocopherol throughout the study. A similar trend was observed in tissue (liver, backfat, leaf fat, semimembranosus, rhomboideus) alpha-tocopherol and serum: the liver had the highest concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of supplemental dietary vitamin E (as DL-alpha-tocopheryl acetate; 0, 15, 30, and 60 IU/d) on serum, platelet, and muscle tocopherol and lipid (cholesterol and triglycerides) concentrations in 32 sheep were investigated in a 60-d trial. Serum, platelet, and muscle alpha-tocopherol concentrations increased linearly (P < .05) with treatment. Platelet tocopherol concentrations were more sensitive to vitamin E intake than either serum or muscle tocopherol. There were no effects on serum lipid concentrations. There were low correlations (P > .05) between serum or platelet tocopherol and either cholesterol or triglycerides or the sum of the two lipid fractions. Correlations between serum or platelet tocopherol and muscle tocopherol were also low (P > .05). Although platelet tocopherol was more sensitive to vitamin E intake than serum tocopherol, serum tocopherol concentrations can be reliably used to estimate vitamin E status. Expressing serum tocopherol relative to blood lipids did not improve the relationship between serum tocopherol and vitamin E intake.

Twenty-six pregnant ewe lambs were used to study the effect of four treatment (T 1 to 4) levels of DL-alpha-tocopheryl acetate (0, 15, 30, and 60 IU.lamb-1.d-1) supplemented 28 d prepartum through 28 d postpartum on placental and mammary gland transfer of alpha-tocopherol. Blood samples were first obtained on d 28 prepartum and thereafter with milk samples at designated intervals up to 28 d postpartum for alpha-tocopherol analyses. Similarly, blood samples were obtained from neonatal lambs on d 1 before suckling and on d 3, 14, and 28 postpartum. Ewe lamb serum tocopherol concentrations averaged .66 micrograms/mL before T administration; 28 d later averages were .93, 1.94, 2.63, and 4.07 micrograms/mL (linear, P < .05) for T 1 to 4, respectively. Supplemental vitamin E had no effect (P > .05) on serum alpha-tocopherol of neonatal lambs, indicating inefficient placental transfer. By d 3, lamb serum tocopherol increased to 1.41, 1.84, 2.43, and 4.46 micrograms/mL (linear, P < .05) for T 1 to 4 following consumption of colostrum and declined to .46, .74, 1.10, and 1.68 micrograms/mL (linear, P < .05) by d 28. On d 1 there was a linear (P < .05) treatment effect on tocopherol in colostrum, with a low concentration of 3.30 micrograms/mL for the control (T 1) and a high of 9.55 micrograms/mL for T 4.(ABSTRACT TRUNCATED AT 250 WORDS)

In a 28-d trial, 35 wethers weighing 35 to 60 kg were used to evaluate serum, liver, pancreas, kidney, diaphragm, heart, and neck muscle alpha-tocopherol concentrations after vitamin E administration as i.m. injections and(or) oral supplementation. Treatments (T) were as follows: 1) i.m. DL-alpha-tocopherol(DL-alpha-ol) d 1, 2) i.m. DL-alpha-tocopheryl acetate(DL-alpha-ac) d 1, 3) i.m. DL-alpha-ol d 1, 7, 14, and 21, 4) T 1 and oral supplementation, 5) T 3 and oral supplementation, 6) oral supplementation, and 7) control, no E supplementation. Supplemented wethers received 500 IU via injection and(or) 30 IU/kg of diet (acetate form). In a second 10-d trial, blood was periodically collected from 20 wethers weighing 32 to 47 kg that had been assigned to T as follows: 1) control, 2) i.m. DL-alpha-ol d 1, 3) i.m. DL-alpha-ac d 1, 4) T 2 d 1 and 7, and 5) T 3 d 1 and 7. Results from repeated measures ANOVA in both trials indicated that there were day x T effects (P < .0001) on serum alpha-tocopherol. Pretreatment serum tocopherol concentrations were .58 and .66 microgram/mL for Trials 1 and 2, respectively. In Trial 1, wethers receiving the four alcohol vitamin E forms showed a rapid increase in serum tocopherol between d 1 and 3, followed by a rapid decline to pretreatment concentrations for T 1, whereas T 3, 4, and 5 maintained higher than pretreatment concentrations after the decline.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue alpha-tocopherol concentrations were determined in 40 lambs following oral supplementation of various forms of vitamin E. Lambs were allocated to 8 dietary groups of 5 animals each and supplemented with or without equimolar amounts (300 mg equivalence) of different vitamin E compounds daily for 60 d as follows: 1) control, no supplemental vitamin E; 2) D-alpha-tocopheryl acetate; 3) DL-alpha-tocopheryl acetate; 4) DL-alpha-tocopheryl nicotinate; 5) D-alpha-tocopheryl polyethylene glycol 1,000 succinate (TPGS); 6) DL-alpha-tocopheryl nicotinate+TPGS; 7) D-alpha-tocopheryl acetate+TPGS; and 8) D-alpha-tocopheryl succinate. At the end of the 60 d the lambs were killed and portions of adrenal, fat, heart, kidney, liver, lung, skeletal (brachiocephalicus and gluteus) muscles, pancreas and spleen were removed. Daily supplementation with various vitamin E compounds (equivalence) in lambs resulted in significant differences in tissue alpha-tocopherol concentration in heart, liver, gluteus medius muscle, and spleen. Correlations between the plasma and tissue alpha-tocopherol levels were highly significant for all tissues except adrenal, fat, and pancreas.

A 61-d study involving 40 crossbred lambs evaluated the effect of various forms of tocopherol provided daily in equimolar amounts on total cholesterol, high-density lipoprotein-cholesterol and triglyceride concentrations in the serum of lambs. Thirty-five lambs were allotted to 7 treatment groups of 5 animals each, supplemented with 300 mg tocopherol either as: 1) DL-alpha-tocopheryl acetate; 2) D-alpha-tocopheryl acetate; 3) D-alpha-tocopheryl succinate; 4) D-alpha-tocopheryl polyethylene glycol 1,000 succinate (TPGS); 5) DL-alpha-tocopheryl nicotinate; 6) DL-alpha-tocopheryl nicotinate (150 mg) + 150 mg TPGS; and 7-D-alpha-tocopheryl acetate (150 mg) + 150 mg TPGS mixed with the commercial flock diet. In addition, another group of 5 lambs were used as control (no vitamin E supplementation). Dietary supplementation of various vitamin E sources resulted in no overall treatment effects for total cholesterol, triglycerides or high density lipoprotein-cholesterol. A significant variation was noticed among animals. The levels of all measured serum components varied throughout the experimental period (P < 0.0001). The day x treatment interaction was not significant (P > 0.05) for any serum measured component. The present data strongly suggest that short-term treatment (< 2 mo) with pharmacological oral doses of various forms of vitamin E did not influence serum lipid metabolism of lambs. The data also showed that the bioavailability of alpha-tocopherol is dependent on the form administered. D-alpha-tocopherol acetate is a highly available form, the bioavailability of which is further increased when combined with D-alpha-tocopheryl polyethylene glycol succinate.

Serum and liver concentrations of selected macro- and trace minerals were determined in Senepol cattle at 8 sites (4 each in a high and low rainfall region) during the dry and wet season on St Croix. At each site an average of 15 mature, lactating cows, grazing native grass/legume pastures without supplementation were blood sampled each season. Liver samples were collected (n = 51) at slaughter from mature animals originating from the same sites. A preliminary analysis indicated no differences in serum mineral concentrations between mature lactating cows and growing heifers. There were differences between sites for serum magnesium (Mg) (P < 0.001), copper (Cu) (P < 0.05) selenium (Se) (P < 0.001) and zinc (Zn) (P < 0.01) in the dry season, and for Cu (P < 0.01), iron (Fe) (P < 0.001) and Zn (P < 0.01) in the wet season. Higher (P < 0.001) serum concentrations of Mg, Cu, Fe and Zn were observed in the dry season, while Se was higher (P < 0.01) in the wet season. Liver concentrations of Cu and Fe were lower (P < 0.01) and liver molybdenum (Mo) (P < 0.001) and Se (P < 0.05) higher during the dry season. The seasonal differences in serum Cu, Se and Zn concentrations have not been observed in other studies in the Central American region. More than 50% of serum samples were deficient in phosphorus (P) regardless of season, and in Cu and Zn during the wet season. Mineral supplementation should be considered.

The effects of temperature and colostrum components on specific gravity in bovine colostrum were investigated. Thirty-nine first milking colostrum samples were collected from Holstein cows. The samples were assayed for alpha-tocopherol, fat, protein, total solids, and IgG. The concentrations of total solids, total protein, total IgG, and fat in colostrum were 26.6, 12.5, 3.7, and 9.4 g/100 g, respectively. A range of 1.8 to 24.7 micrograms/ml for alpha-tocopherol was measured in the colostrum samples. Specific gravity of the colostrum was measured using a hydrometer in increments of 5 degrees C from 0 to 40 degrees C. Specific gravity explained 76% of the variation in colostral total IgG at a colostrum temperature of 20 degrees C. The regression model was improved only slightly with the addition of protein, fat, and total solids. The model for samples at 20 degrees C was IgG (milligrams per milliliter) = 958 x (specific gravity) - 969. Measurement of specific gravity at variable temperatures necessitated inclusion of temperature in the model for estimation of IgG. Inclusion of the other components of colostrum into the model slightly improved the fit. The regression model for samples at variable temperatures was as follows: IgG (milligrams per milliliter) = 853 x (specific gravity) + .4 x temperature (Celsius degrees) - 866.

Thirty-five crossbred wethers were used to determine the concentrations of alpha-tocopherol in serum and tissues after oral supplementation of six different vitamin E product forms. Five wethers were assigned to each of the following treatments: 1) control, no supplemental vitamin E (C), 2) emulsifiable DL-alpha-tocopheryl acetate-dry (Rovimix E-50% SD), 3) nonemulsifiable DL-alpha-tocopheryl acetate-dry (Rovimix E-50% Ads), 4) emulsifiable DL-alpha-tocopheryl acetate-liquid (Rovimix E-40% Dispersible Liquid Concentrate [DLC]); 5) emulsifiable DL-alpha-tocopherol-liquid (Hoffmann-La Roche, E-40% DLC alcohol), 6) micellized DL-alpha-tocopheryl acetate-liquid (Bioglan, Inc., E-20%); and 7) micellized DL-alpha-tocopherol-liquid (Bioglan, Inc., E-20%). Animals were supplemented daily with 1,000 IU of their respective vitamin E sources for 56 d. Blood samples were collected daily from d 0 to 7 and weekly until d 56. Animals were subsequently killed by exsanguination after stunning and eight different tissues were collected for alpha-tocopherol analysis. There were effects of day, treatment, and day x treatment interaction on serum alpha-tocopherol. All supplemented groups were higher in serum alpha-tocopherol concentration than were the C wethers. The emulsifiable vitamin E alcohol liquid product form (Treatment 5) yielded higher (P less than .01) serum alpha-tocopherol concentration than the emulsifiable acetate liquid product (Treatment 4). Sheep on Treatment 5 reached maximum concentration on d 1, sheep on Treatment 6 on d 2, and the sheep on the remaining Treatments by d 3. Blood sera alpha-tocopherol concentrations stabilized by d 6 in all supplemented groups.(ABSTRACT TRUNCATED AT 250 WORDS)

A study was carried out to assess the bioavailabilities of several forms of vitamin E in lambs. A total of 40 lambs was allotted to eight dietary groups of five each and supplemented or not daily for 60 d with equimolar amounts of different vitamin E compounds as follows: 1) control, no supplemental vitamin E, 2) DL-alpha-tocopheryl acetate, 3) D-alpha-tocopheryl acetate, 4), D-alpha-tocopheryl succinate, 5) D-alpha-tocopheryl polyethylene glycol 1,000 succinate (TPGS), 6) DL-alpha-tocopheryl nicotinate, 7) DL-alpha-tocopheryl nicotinate+ TPGS, or 8) D-alpha-tocopheryl acetate + TPGS. During these 60 d, serum alpha-tocopherol concentrations in the control lambs remained constant and lower (P less than .05) than in lambs that received all treatments. Various indices of bioavailability, including Cmax-C(i) (concentration maximum-concentration initial), Ct-C(i) (concentration terminal-concentration initial), areas under the serum concentrations profiles, and pooled increment were higher (P less than .05) with D-alpha-tocopheryl acetate+ TPGS than in the other groups, suggesting a synergism between these forms. No such effect was observed between nicotinate and TPGS. For the TPGS, a water-soluble form of vitamin E, the indices of bioavailability were lower (P less than .05) than for the other groups. D-alpha-tocopheryl acetate resulted in a bioavailability that outranked all the other forms of vitamin E, except those of D-alpha-tocopheryl acetate + TPGS. A slightly higher bioavailability index was observed for D-alpha-tocopheryl succinate than for DL-alpha-tocopheryl nicotinate.(ABSTRACT TRUNCATED AT 250 WORDS)

Forty-three crossbred wethers weighing 35 to 60 kg were used to investigate the effect of a single i.m. injection of DL-alpha-tocopherol (DL-alpha-ol). Animals were offered 1 kg/d of a basal diet containing 25 ppm of vitamin E. Lambs were randomly assigned to one of five DL-alpha-ol injection treatments as follows: 1) control (placebo, 0 IU), 2) 125 IU, 3) 250 IU, 4) 500 IU, or 5) 1,000 IU. Blood samples were taken via jugular venipuncture on d 1 before treatment administration and thereafter at designated intervals up to 360 h postinjection. The i.m. injections of DL-alpha-ol irrespective of dose increased serum alpha-tocopherol. Results showed a dose x time interaction (P less than .0001) across all treatments. Serum alpha-tocopherol increased rapidly to maximum concentration during the first 8 to 12 h for all non-zero treatments, followed by a rapid decline to pretreatment values. The mean serum alpha-tocopherol concentration at 0 h was .69 microgram/mL. Estimated peak serum alpha-tocopherol concentrations +/- SE were 6.68 +/- 1.04, 9.62 +/- 1.04, 21.66 +/- 2.37, and 50.75 +/- 7.05 micrograms/mL for Treatments 2 through 5, respectively. Results showed a quadratic dose effect (P less than .0003) on maximum response with apparently no effect on time taken to reach this peak. There was also a quadratic dose effect (P less than .0001) on the area under the concentration-time curve. The time taken for serum alpha-tocopherol to return to pretreatment levels increased with dose (56, 64, 67, and 74 h, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Heritabilities of and genetic, environmental, and phenotypic correlations among serum amounts of calcium, phosphorus, and magnesium and weight at weaning (WCa, WP, WMg, and WW, respectively) were estimated for an Angus (A)-Brahman(B) multibreed herd located at the Pine Acres Research Station of the University of Florida, Citra. Records were obtained from 380 calves produced by mating A, .75A .25B, .5A .5B, .25A .75B, B, and Brangus sires across dams of the same breed groups, except for .25A .75B, during 1989 and 1990. Restricted maximum likelihood procedures were used to compute variance and covariance components. Estimates of heritability were .39 (WCa), .40 (WP), .36 (WMg), and .35 (WW). Estimates of genetic, environmental, and phenotypic correlations were .66, .55, .57 (WCa, WP), .70, .71, .70 (WCa, WMg), 1.00, .86, .88 (WCa, WW), .50, .51, .51 (WP, WMg), .78, .60, .63 (WP, WW), and .86, .73, .75 (WMg, WW). These correlations indicate that serum Ca, P, and Mg could be used in multiple-trait genetic evaluation procedures to help identify animals that require low amounts of these macrominerals for preweaning growth. This may prove advantageous in mineral-deficient regions.

Amounts of serum calcium, phosphorus, and magnesium at weaning (WCa, WP, and WMg, respectively) and weaning weights (WW) were obtained from 380 Angus (A), Brahman (B), and A x B calves of various expected A and B fractions reared at the Pine Acres Research Station of the University of Florida, Citra from 1989 to 1990. Calves were produced by mating A, .75A, .25B, .5A .5B, .25A .75B, B, and Brangus (.625A .375B) sires to dams of the same expected breed fractions, except for .25A .75B dams. Best linear unbiased estimates (BLUE) of genetic effects, expressed as regression coefficients, were 1) -15.07 +/- 13.65 mg of WCa, -11.21 +/- 12.07 mg of WP, -1.23 +/- 2.99 mg of WMg, and .66 +/- 1.18 kg of WW for the difference between A and B additive direct; 2) 9.79 +/- 6.94 mg of WCa, -5.72 +/- 6.14 mg of WP, 1.64 +/- 1.52 mg of WMg, and .52 +/- .60 kg of WW for the difference between A and B additive maternal; 3) 242.21 +/- 51.56 mg of WCa, 66.67 +/- 45.62 mg of WP, 52.16 +/- 11.27 mg of WMg, and 22.61 +/- 4.44 kg of WW for A x B nonadditive direct; and 4) 373.63 +/- 38.44 mg of WCa, 93.96 +/- 34.02 mg of WP, 69.90 +/- 8.41 mg of WMg, and 36.83 +/- 3.31 kg of WW for A x B nonadditive maternal. Nonadditive (A x B) effects were the main factors affecting total (sum of additive plus nonadditive) genetic effects in this multibreed population. Total genetic effects were used to rank breed group of sire x breed group of dam combinations.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood and hepatic tocopherol concentration following i.m. injection or oral supplementation was studied in nonlactating dairy cows and pregnant beef heifers, respectively. In Experiment 1, cows received a single i.m. injection of either 4500 IU of d-alpha-tocopherol or 4500 or 7500 IU of dl-alpha-tocopheryl acetate. Plasma and liver tocopherol concentrations were recorded before and up to 4 wk postinjection. In Experiment 2, heifers received either 0, 1000, 2000, or 4000 IU of dl-alpha-tocopheryl acetate daily in the ration for 3 wk. Serum and hepatic tocopherol concentrations were measured before, during, and 3 wk following supplementation. In Experiment 1, level of tocopheryl acetate given influenced plasma and hepatic tocopherol concentrations. Plasma alpha-tocopherol concentration was greater in cows given unesterified tocopherol than an equivalent amount of tocopherol acetate. There was a quadratic relationship between plasma and hepatic tocopherol concentration. In Experiment 2, increasing dietary intake of dl-alpha-tocopheryl acetate failed to increase markedly tocopherol levels in serum or liver. There was no relationship between serum and hepatic tocopherol concentrations. Prior to the trials, serum levels in Experiment 2 were less than plasma levels in Experiment 1, but hepatic levels were greater. Physiological state can influence the relation between circulating and stored reserves of tocopherol, and circulating tocopherol concentration may not be a good indicator of its reserves.