Impact of molybdenum on the copper status of red deer (Cervus elaphus)

AIM: To determine the effect of increasing molybdenum (Mo) intakes on serum and liver copper (Cu) concentrations and growth rates of grazing red deer (Cervus elaphus).

METHODS: Molybdenum- and Cu-amended fertilisers were applied to six 1.1-ha paddocks in a 3 × 2 design. Three levels of Mo were applied on two paddocks at each level in mid April (designated Day 1); levels were: none (control), 0.5 (medium) and 1.0 (high) kg Mo/ha as sodium molybdate. In late May (Day 39), two levels of Cu (none and 3.0 kg Cu/ha, as copper sulphate) were applied to each of the three levels of Mo-treated paddocks. Pasture Mo, Cu and sulphur (S) concentrations were measured at about fortnightly intervals. In late June (Day 74), ten 6-month-old red deer hinds were placed on the six experimental pastures, and serum and liver Cu concentrations were monitored at about monthly intervals for 102 days. The hinds were weighed on four occasions during the trial.

RESULTS: Mean pasture Mo concentrations on Day 56 were 2, 4.6 and 11.3 mg/kg dry matter (DM) for the untreated control, medium and high Mo-treated pastures, respectively. Pasture Cu concentration was 95 mg/kg DM on Day 59, 53 mg/kg DM on Day 90, and 9 mg/kg DM by Day 153. Mean S concentration in pasture was 3.3 (range 3.03–3.45) g/kg DM. Copper application to pasture had no significant effect on serum and liver Cu concentrations in deer so data were pooled within Mo treatment. Mean initial (Day 74) serum Cu concentration was 9.2 µmol/L. In the deer grazing the control Mo pasture, this increased to 10.3 µmol/L on Day 112, before decreasing to 6.4 µmol/L on Day 176. In deer grazing the medium and high Mo-treated pastures, mean serum Cu concentrations were 3.8 and 3.9 µmol/L, respectively, on Day 112, and 2.5 and 3.3 µmol/L, respectively, on Day 176. Mean initial (Day 74) liver Cu concentration was 131 µmol/kg fresh tissue. In the deer grazing the control Mo pasture, this declined to 120 and 52 µmol/kg on Days 112 and Day 176, respectively. In deer grazing the medium and high Motreated pastures, liver Cu concentrations decreased to 55 and 52 µmol/kg fresh tissue, respectively, on Day 112, and 21 and 20 µmol/kg fresh tissue, respectively, on Day 176. Mean serum and liver Cu concentrations were not significantly different between deer grazing the medium and high Mo-treated pastures, and were lower (serum p=0.003, liver p<0.001) in those groups than in deer grazing the untreated control pastures. No clinical signs of Cu deficiency associated with lameness were observed. Deer grazing pastures that had Mo concentrations >10 mg/kg DM had lower (p=0.002) growth rates (100 vs 130 g/day) than those on pastures containing <2.4 mg Mo/kg DM.

CONCLUSION: Increasing pasture Mo concentrations from 2 mg/kg DM to ≥4.6 mg/kg DM significantly reduced serum and liver Cu concentrations in grazing deer. Reduced growth rate was observed at pasture Mo concentrations >10 mg/kg DM.     

The impact of highly concentrated Mo and Cu dietary supplements,fed as a bolus,on the efficacy of chelated versus inorganic Cu in cattle on a low-Cu diet

AIM: To compare the efficacy of chelated versus inorganic forms of dietary Cu supplements, fed as a bolus, when challenged by a daily bolus of dietary Mo in cattle on a low-Cu diet.

METHODS: Forty non-lactating, Friesian dairy cows of adequate Cu status were assigned to four groups and fed a basal diet of baled silage containing 5.3 mg Cu and 0.4 mg Mo/kg DM. The experimental design was a factorial of two chemical forms of supplemental Cu and two levels of Mo intake, provided as pelleted grain supplements made from crushed barley/molasses plus Cu and Mo. The supplements contained 140 mg Cu/kg as Cu sulphate pentahydrate (CS), 140 mg Cu/kg as Cu glycinate (CG), CS plus 38 mg Mo/kg as sodium molybdate (CS+Mo), or CG plus 38 mg Mo/kg (CG+Mo). Commencing on Day 0, supplements were fed once daily (offered 1–1.2 kg/cow) and were completely consumed within 5–10 minutes, which constitutes a bolus type of administration. Liver samples were collected by biopsy at Days ?24, 13, 41 or 47, and 69 for Cu determinations.

RESULTS: The diets fed to the Cu+Mo groups were roughly equivalent to 25 mg Cu and 5.7 mg Mo/kg DM. Mean initial concentration of Cu in liver for all groups was 516 (SE 54) μmol Cu/kg fresh tissue. In cows supplemented with CS and CG, the final (Day 69) concentrations increased (p<0.01) to 939 (SE 166) and 853 (SE 163) μmol Cu/kg, respectively. These values were not different (p=0.72). For groups CS+Mo and CG+Mo, the final concentrations of 535 (SE 122) and 453 (SE 102) μmol Cu/kg were not different from initial values or from each other (p>0.25). The rate of accumulation of Cu in liver following bolus Cu and Mo intake was highly variable but was not affected by initial concentration of Cu in liver (p>0.9) or by the form of Cu (p>0.6). Mean rates of accumulation of Cu in liver were 4.0 (SD 3.8) and 0.65 (SD 2.0) μmol Cu/kg fresh tissue/day for the Cu-only treatments and the Cu+Mo treatments, respectively.

CONCLUSIONS: When fed together as a bolus, high Mo intake negated the effect of supplemental Cu but it did not reduce liver Cu stores. There was no difference in the reaction of dietary Mo with chelated Cu (as glycinate) versus inorganic Cu (as sulphate) dietary supplements.     

Impact of molybdenum on the copper status of red deer (Cervus elaphus)

AIM: To determine the effect of increasing molybdenum (Mo) intakes on serum and liver copper (Cu) concentrations and growth rates of grazing red deer (Cervus elaphus). METHODS: Molybdenum- and Cu-amended fertilisers were applied to six 1.1-ha paddocks in a 3 x 2 design. Three levels of Mo were applied on two paddocks at each level in mid April (designated Day 1); levels were: none (control), 0.5 (medium) and 1.0 (high) kg Mo/ha as sodium molybdate. In late May (Day 39), two levels of Cu (none and 3.0 kg Cu/ha, as copper sulphate) were applied to each of the three levels of Mo-treated paddocks. Pasture Mo, Cu and sulphur (S) concentrations were measured at about fortnightly intervals. In late June (Day 74), ten 6-month-old red deer hinds were placed on the six experimental pastures, and serum and liver Cu concentrations were monitored at about monthly intervals for 102 days. The hinds were weighed on four occasions during the trial. RESULTS: Mean pasture Mo concentrations on Day 56 were 2, 4.6 and 11.3 mg/kg dry matter (DM) for the untreated control, medium and high Mo-treated pastures, respectively. Pasture Cu concentration was 95 mg/kg DM on Day 59, 53 mg/kg DM on Day 90, and 9 mg/kg DM by Day 153. Mean S concentration in pasture was 3.3 (range 3.03-3.45) g/kg DM. Copper application to pasture had no significant effect on serum and liver Cu concentrations in deer so data were pooled within Mo treatment. Mean initial (Day 74) serum Cu concentration was 9.2 micromol/L. In the deer grazing the control Mo pasture, this increased to 10.3 micromol/L on Day 112, before decreasing to 6.4 micromol/L on Day 176. In deer grazing the medium and high Mo-treated pastures, mean serum Cu concentrations were 3.8 and 3.9 micromol/L, respectively, on Day 112, and 2.5 and 3.3 micromol/L, respectively, on Day 176. Mean initial (Day 74) liver Cu concentration was 131 micromol/kg fresh tissue. In the deer grazing the control Mo pasture, this declined to 120 and 52 micromol/kg on Days 112 and Day 176, respectively. In deer grazing the medium and high Mo-treated pastures, liver Cu concentrations decreased to 55 and 52 micromol/kg fresh tissue, respectively, on Day 112, and 21 and 20 micromol/kg fresh tissue, respectively, on Day 176. Mean serum and liver Cu concentrations were not significantly different between deer grazing the medium and high Mo-treated pastures, and were lower (serum p=0.003, liver p<0.001) in those groups than in deer grazing the untreated control pastures. No clinical signs of Cu deficiency associated with lameness were observed. Deer grazing pastures that had Mo concentrations >10 mg/kg DM had lower (p=0.002) growth rates (100 vs 130 g/day) than those on pastures containing <2.4 mg Mo/kg DM. CONCLUSION: Increasing pasture Mo concentrations from 2 mg/kg DM to > or =4.6 mg/kg DM significantly reduced serum and liver Cu concentrations in grazing deer. Reduced growth rate was observed at pasture Mo concentrations >10 mg/kg DM.     

Loss of reserves of Cu in liver when Cu supplements are withdrawn from dairy herds in the Waikato region

Abstract

AIM: To monitor the consequences of withdrawing mineral Cu supplements from two dairy herds with initially high concentrations of Cu in liver.

METHODS: Two herds were selected from dairy farms in the Waikato region of New Zealand that participated in an earlier survey of Cu supplementation practices and Cu status of dairy cows. The herds were fed pasture, grass and maize silage, plus palm kernel expeller (PKE) containing 25–30 mg Cu/kg dry matter (DM) fed at 2–4 kg/cow/day. No mineral Cu supplements were supplied from January 2009. Pasture samples were collected for mineral analysis in September 2008 and April 2009. Concentration of Cu in liver biopsies from the same 9–10 cows per herd was measured on three occasions between April 2009 and May 2010.

RESULTS: Pastures on both farms contained 10 mg Cu/kg DM, 0.1–0.5 mg Mo/kg DM and 3.5–4.0 g S/kg DM. The initial herd mean concentrations of Cu in liver were 1,500 (SD 590) and 1,250 (SD 640) μmol Cu/kg fresh tissue. In the absence of mineral Cu supplements, those mean concentrations decreased over 12 months to 705 (SD 370) and 1,120 (SD 560) μmol Cu/kg fresh tissue, respectively. For cows in the first herd, the rate of depletion of liver Cu reserves was influenced by initial concentration of Cu, such that high concentration led to faster loss according to first-order kinetics.

CONCLUSIONS: Mineral Cu supplementation was not necessary over 12 months for two dairy herds with mean concentrations of Cu in liver >1,250 μmol Cu/kg fresh tissue, grazing pastures containing 10 mg Cu/kg DM and concentrations of Mo <1 mg/kg DM. The quantity and particularly the duration of feeding PKE appeared to be a factor in whether or not the herd lost substantial reserves of Cu in liver during the year. However, the Cu status of both herds in this study was more than adequate to support late pregnancy and mating.

CLINICAL REVELANCE: Copper status of the herd should be monitored and on-farm management of Cu nutrition should take into account all sources contributing to daily intake of Cu. Where Cu supplementation has been excessive and there is risk of chronic Cu toxicity, mineral Cu supplements may be withdrawn for a period commensurate with the expected rate of liver Cu depletion.     

The effects of levamisole on oxidative stress induced by copper intoxication in broilers

Abstract

AIM: To determine the effects of Cu and levamisole on concentrations of Cu and Fe in plasma and liver, and the effects of levamisole on lipid peroxidation induced by Cu intoxication in broiler chickens.

METHODS: In a 2×4 factorial study, 80 one-day-old Ross PM3 broiler chicks were fed diets for 21 days containing either 8 mg/kg Cu (Low Cu) or 250 mg/kg Cu (High Cu) and were treated with 0 (L0), 4 (L4), 8 (L8) or 16 (L16) mg/kg bodyweight levamisole per day from Day 7 of the study, on three consecutive days in their drinking water. This treatment was repeated three times, at 3-day intervals. On Day 21, blood samples were collected from each bird for analysis of concentrations of Cu, Fe and malondialdehyde, and activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), superoxide dismutase, catalase and glutathione peroxidase (GSH-Px). The birds were killed and liver samples collected for analysis of Cu and Fe.

RESULTS: Mean concentrations of Cu and Fe in plasma, and Cu in liver, were increased overall in the High Cu groups compared with the Low Cu groups (p<0.001). Compared with the L0 treatment group on the High Cu diet, treatments L4, L8 and L16 decreased concentrations of Cu in plasma, and L8 and L16 increased concentration of Cu in liver (p<0.05). Mean activities of AST and ALT were increased in untreated birds (L0) fed the High compared with Low Cu diets (p<0.01). In birds receiving the High Cu diet, treatments L4 and L8 decreased activities of AST, and L4 and L16 decreased activity of ALT, compared with L0 (p<0.05). The High Cu diet induced an oxidative stress characterised by increased mean concentrations of malondialdehyde and decreased activities of superoxide dismutase, catalase and GSH-Px (p<0.001). Concentration of malondialdehyde, and activities of superoxide dismutase and catalase were not changed following levamisole treatment in birds on the High Cu diet, and activity of GSH-Px was decreased by the L4 and L8 treatments compared with the L0 group.

CONCLUSIONS AND CLINICAL RELEVANCE: The results of the study suggest that treatment with levamisole might alleviate the harmful effects of Cu on the liver, as demonstrated by decreased activities of AST and ALT induced by a diet containing 250 mg/kg Cu.     

Changes in liver copper concentration of thoroughbred foals from birth to 160 days of age and the effect of prenatal copper supplementation of their dams

OBJECTIVES: To monitor the change in liver copper concentration of Thoroughbred foals from birth to 160 days of age and to determine the effects of supplementation by two injections of copper edetate given to dams in late gestation on the liver copper concentration of their foals at birth. PROCEDURE: Ten mares pregnant to the same stallion were randomised into two groups on the basis of age, liver copper concentration and expected foaling date. The treatment group mares were given 100 mg and 250 mg copper edetate intramuscularly during the ninth and tenth months of gestation respectively. Foals had liver biopsies taken weekly in the first month of life, then monthly for four months. Foals were euthanased at 160 days of age; liver samples were taken and the copper concentrations were determined. RESULTS: Two distinct patterns of age dependent decline in liver copper concentration were evident. The mean (+/- SD) liver copper concentration of the foals was high at birth (374 +/- 130 mg/kg DM), and for seven it declined to adult values by 160 days of age (21 +/- 6 mg/kg DM). In three foals the decline was at a slower rate than in the other seven and at 160 days of age the mean concentration was 162 +/- 32 mg/kg DM. Repeated measures analysis showed significant differences between each biopsy (P < 0.01) and between 'normal' and 'accumulator' foals (P < 0.002). Copper injections given to mares in late pregnancy had no effect on the liver copper concentration of foals at birth. CONCLUSIONS: The significance of the two patterns of age dependant decline in liver copper concentration is unknown. Parenteral copper supplementation of the dam in late gestation had no effect on the liver copper concentration of the foal at birth.     

Estimated copper requirements of angus and simmental heifers

In Exp. 1, Simmental (n = 21) and Angus (n = 21) heifers, approximately 9 mo of age, were used in a 160-d study to determine the effect of dietary Cu on growth and Cu status. Two- or three-yr-old first-calf heifers (21 Angus and 21 Simmental) entering into their last trimester of pregnancy were used in Exp. 2 to estimate Cu requirements of the two breeds during gestation and early lactation. Treatments in both studies consisted of 0 (control), 7, or 14 mg of supplemental Cu (as CuSO4)/kg of DM. The control corn silage-based diets contained 6.4 and 4.4 mg of Cu/kg of DM in Exp. 1 and 2, respectively, and 1.2 mg of Mo/kg. Dietary Cu did not affect performance in either breed in Exp. 1. Copper supplementation generally did not affect plasma Cu concentrations in Angus heifers, but increased (P < 0.05) plasma Cu in Simmental heifers from d 37 until the end of Exp. 1. Final liver Cu concentrations were lower (P < 0.05) than initial concentrations in control Angus and Simmental heifers; however, liver Cu increased (P < 0.01) in Cu-supplemented heifers. In Exp. 2, Cu supplementation of the control diet increased (P < 0.05) plasma Cu during gestation and greatly increased (P < 0.01) liver Cu in both breeds. Calves born to cows not supplemented with Cu also had lower plasma Cu concentrations than Cu-supplemented calves by 73 d of age. In both studies, control Simmental heifers had lower (P < 0.05) plasma Cu concentrations than Angus on most sampling dates. When Cu was supplemented at 7 or 14 mg/kg of DM,few differences in plasma Cu concentrations were observed between breeds. Results suggest that Angus heifers have a lower minimal Cu requirement than Simmental. Based on liver Cu, the control diets containing 4.4 or 6.4 mg of Cu/kg of DM did not meet the Cu requirement of either breed during gestation and lactation or growth. Addition of 7 mg of Cu/kg of DM to the control diets met Cu requirements of both breeds.     

The effect of a temporal change in ingestion rates of fluorine (F) in soil on the concentration of F in serum and bone of young sheep

AIM: To determine the changes in concentrations of fluorine (F) in serum and bone of young sheep given a high intake of F, as F in soil, followed by a low intake of F, to simulate the varying intakes experienced by grazing sheep. METHODS: Sixty autumn-born, weaned, mixed-sex lambs were randomly divided into two groups (n=30). One group (Control) was fed a low-F (12 mg/kg dry matter; DM) lucerne/ grain diet for 345 days, while the other group (High soil-F) was fed a high-F (224 mg/kg DM) lucerne/grain diet containing 10% soil for 94 days and then a low-F diet for a further 251 days. Blood samples were collected on Days 1, 32, 94, 108, 153, 214, 280 and 345, to determine concentrations of F in serum. Groups of five or six animals from each group were killed on Days 1, 94, 153, 214, 280 and 345, to collect radii and humeri for determination of F content. The sheep were weighed at about 6-8-weekly intervals. RESULTS: Initial liveweight of the sheep was 22.1 (standard error (SE) 1.12) kg and the mean liveweight gains were 270 (SE 22.1) and 170 (SE 12.4) g/day from Days 1 to 94 and 95 to 330, respectively. The mean initial (Day 1) concentration of F in serum was 0.03 (SE 0.005) mg/L, and this changed very little for animals on the low-F diet. In sheep on the high soil-F diet, the concentration of F in serum reached 0.38 (SE 0.021) mg/L at Day 94 but after being placed on the low-F diet concentrations decreased to 0.04 (SE 0.006) mg/L after 14 days (Day 108) and then remained at about this low level for the remainder of the duration of the study. The mean concentrations of F in the humerus and radius of the lambs at Day 1 were 161 (SE 19.4) and 159 (SE 20.4) mg/kg DM, respectively, which increased to 2,784 (SE 80.6) and 1,805 (SE 51.5) mg/kg DM, respectively, at Day 94 in lambs fed the high soil-F diet, then decreased to 1,075 (SE 58.1) and 1,064 (SE 61.6) mg/kg DM at Day 153, and then progressively increased to 1,669 (SE 57.7) and 1,312 (SE 30.8) mg/kg DM at Day 345. CONCLUSIONS: The ingestion of F in soil by sheep markedly increased their concentrations of F in serum and bone, but when the soil was removed and they were fed a low-F diet, concentrations of F in serum decreased to baseline levels within 14 days while concentrations in the bone only decreased to 60-70% of the peak concentration, indicating that some of the F in bone was remobilised.     

Cupric oxide needles for grazing cattle consuming low-copper, high-molybdenum forage and high-sulfate water

Oxidized copper wire, commonly referred to as copper oxide needles (CuON), was evaluated using purebred Hereford cows and their calves. Thirty-seven cows were allocated to Cu treatments of 0, 25 or 50 g CuON (79.9% Cu in CuON) with 12, 12 and 13 cows per treatment, respectively; calves within cow treatments were allocated to treatment of 0 and 20 g CuON. Single oral doses of CuON were given at the start of a grazing trial that lasted 92 d. Cows and calves were weighed and blood samples were taken on d 0, 28, 63 and 92; liver biopsies were taken on d 0, 28 and 92 of the grazing trial. Cattle were consuming grass forage with mean concentrations on d 0, 28, 63 and 92 of the grazing trial ranging from 1.6 to 5.5 mg/kg DM for Cu, 2.5 to 5.5 mg/kg DM for Mo and 1.3 to 1.5 g/kg DM for total S. The water consumed by cattle contained 947 mg sulfate per liter (SE = 13.2, n = 4). Body weight of cows and calves was not influenced (P greater than .05) by CuON. Liver Cu was higher (P less than .01) in treated cows and calves but was not different (P greater than .05) between cows dosed with 25 or 50 g CuON. Treatment of cows and calves with CuON had no influence (P greater than .05) on the concentration of Fe or Mo in liver or plasma, the concentration of Cu and ceruloplasmin activity in plasma, or the concentration of Zn in liver. Plasma Zn did not differ (P greater than .05) in cows, but it was higher (P less than .05) in the calves suckling cows treated with CuON. It was concluded that dosing cows and calves with CuON resulted in a higher Cu content of liver but did not adversely influence the metabolism of Fe or Zn or modify the concentration of Mo in the plasma or liver of cows or calves.     

Effects of dietary copper concentration and source on performance and copper status of growing and finishing steers

Performance and Cu status were measured in growing and finishing steers supplemented with different copper (Cu) concentrations and sources. Sixty Angus (n = 36) and Angus x Hereford (n = 24) steers were stratified by weight and initial liver Cu concentration within a breed and randomly assigned to treatments. Treatments consisted of 1) control (no supplemental Cu); 2) 20 mg Cu/kg DM from Cu sulfate (CuSO4); 3) 40 mg Cu/kg DM from CuSO4; 4) 20 mg Cu/ kg DM from Cu citrate (C6H4Cu2O7); 5) 20 mg Cu/kg DM from Cu proteinate; and 6) 20 mg Cu/kg DM from tribasic Cu chloride (Cu2(OH)3Cl). A corn silage-soybean meal-based diet that was analyzed to contain 10.2 mg of Cu/kg DM was fed for 56 d. Steers were then switched to a high-concentrate diet that was analyzed to contain 4.9 mg of Cu/kg DM. Equal numbers of steers per treatment were slaughtered after receiving the finishing diets for either 101 or 121 d. Performance was not affected by Cu level or source during the growing phase. Gain, feed intake, and feed efficiency were reduced (P < .05) by Cu supplementation during the finishing phase. Plasma and liver Cu concentrations were higher in steers receiving supplemental Cu at the end of both the growing and finishing phases. Steers supplemented with 40 mg Cu/kg DM from CuSO4 had higher (P < .05) liver Cu concentrations than those supplemented with 20 mg Cu/kg DM from CuSO4. Liver Cu concentrations did not increase over the finishing phase relative to liver Cu concentrations at the end of the growing phase. These results indicate that as little as 20 mg/kg of supplemental Cu can reduce performance in finishing steers.     

The effect of copper-amended fertiliser and copper oxide wire particles on the copper status of farmed red deer (Cervus elaphus) and their progeny

AIM: To determine changes in serum and liver copper concentrations in postnatal, weaner, yearling, and mature deer after grazing pasture topdressed with copper (Cu) at two rates of application of copper sulphate (CuSO4(.)5H2O), and following oral administration of copper oxide (CuO) wire particles to some of the deer. METHODS: In mid-March 2000 (Year 1), 1.1-ha paddocks (two/treatment) of ryegrass/white clover pasture received either 0 (Control), 6 (Low) or 12 (High) kg CuSO4(.)5H2O /ha applied with 250 kg potash superphosphate/ha. They were grazed by 4-month-old red deer hinds (n=11/treatment) from mid-April 2000 until early March 2001. In mid-March 2001 (Year 2), the pastures were topdressed again as for Year 1, and the original hinds, now yearlings which had grazed as a single group between studies, were returned to their respective treatments in mid-April 2001 and remained on the trial until mid-March 2002. They were mated during April/May. The pastures were also grazed by pregnant mature hinds (n=8/treatment) from mid-May 2001. As the Cu status (i.e. liver Cu concentration) of the yearling hinds on the pasture treated with 6 kg CuSO4(.)5H2O/ha was not significantly different from the untreated animals, in late July 2001 the yearling and mature deer on this treatment were treated orally with 10 g CuO wire particles. The mature hinds calved in November and the yearling hinds in December. Pasture samples were collected at about monthly intervals to determine concentrations of Cu and other minerals. In Year 1, liver biopsies and blood samples were collected at 4-6-weekly intervals for determination of Cu concentrations. In Year 2, samples were collected similarly at 6-12-weekly intervals. Liver biopsies and blood were also collected from progeny, along with milk from their dams. Liveweights were determined at 3-7-monthly intervals, as well as data on calving/mortality rates. RESULTS: Pasture Cu concentrations before the application of CuSO4(.)5H2O were 6-9 mg Cu/kg dry matter (DM) and remained at this level in the untreated Control paddocks throughout the study. In Year 1, 28 days after treatment, pasture Cu concentration was 25 and 35 mg Cu/kg DM for the Low and High treatments, respectively; while at the same time for the same treatments in Year 2 it was 20 and 60 mg/kg DM, respectively. A second 60 mg Cu/kg DM peak also occurred on Day 85 in Year 2 with the High treatment. The pasture Cu concentration returned to 6-9 mg/kg DM, and there were no differences between treatments at Days 80 and 150 in Years 1 and 2, respectively. In Years 1 and 2, the Low treatment had no significant effect on the Cu status of the weaner and yearling hinds, respectively, when compared with that of animals grazing the untreated Control pastures. Weaner (Year 1) and yearling (Year 2) deer on the High treatment had significantly higher mean serum and liver Cu concentrations in the late winter and spring period when compared with those on untreated Control pastures. CuO wire particles increased the mean serum Cu concentration at Days 60 and 180, and liver Cu concentration at Day 60, in yearling hinds. A similar effect was observed in mature hinds. Regardless of Cu treatment, the liver Cu concentration of the 1-4-week-old progeny was markedly greater (p<0.001) than that of their dams, and then decreased significantly until weaning in March. In progeny of treated yearling hinds, but not mature hinds, serum and liver Cu concentrations were significantly higher (p=0.013) than progeny of untreated dams. CONCLUSION: Topdressing pastures with CuSO4(.)5H2O at a rate of 12 kg/ha, but not 6 kg/ha, in mid-March was effective in increasing the Cu status of weanling hinds; while pastures topdressed with 12 kg CuSO4(.)5H2O /ha in mid-March and dosing hinds with 10 g CuO in late July were effective in increasing the Cu status of pregnant hinds, and in the case of the yearling hinds, significantly improved the Cu status of their progeny from birth to weaning.     

Influence of dietary chromium yeast supplementation on apparent trace elements metabolism in growing camel (<Emphasis Type="Italic">Camelus dromedarius</Emphasis>) reared under hot summer conditions

This study aimed to evaluate the effect of dietary chromium (Cr) supplementation on the apparent metabolism of some trace elements in camel calves reared under hot summer conditions. The study was conducted on a total of 15 male camel calves (5–6 months old) reared under hot summer conditions for 12 weeks. The animals were housed individually under shelter and divided into three dietary treatment groups (diets supplemented with 0.0, 0.5, or 1.0 mg Cr/kg DM), five animals each. At the end of the study, a metabolic trial was conducted on all camels for the evaluation of trace elements metabolism. Cr excretion, absorption, and retention showed an increasing trend with the increasing level of dietary Cr supplementation. Dietary Cr supplementation at 0.5 mg Cr/kg DM to camel calves resulted in a significant (P < 0.05) increase in Cu and an increasing trend in Zn and Mn excretion via urine and feces. However, Fe retention increased significantly (P < 0.05) in camel calves fed on diet supplemented with Cr. Dietary Cr supplementation to camel calves resulted in an increasing trend of plasma Cr concentration, while plasma concentration of Cu and Zn tended to decrease and without any effect on plasma Fe concentration. The results of the present study suggests that care should be taken for the negative interaction of Cr with the utilization of other trace elements, in cases where Cr is supplemented to the diet as a feed additive to promote growth and immunity under hot climatic conditions.     

Bioavailability of copper from copper glycinate in steers fed high dietary sulfur and molybdenum

Sixty Angus (n = 29) and Angus-Sim-mental cross (n = 31) steers, averaging 9 mo of age and 277 kg of initial BW, were used in a 148-d study to determine the bioavailability of copper glycinate (CuGly) relative to feed-grade copper sulfate (CuSO(4)) when supplemented to diets high in S and Mo. Steers were blocked by weight within breed and randomly assigned to 1 of 5 treatments: 1) control (no supplemental Cu), 2) 5 mg of Cu/kg of DM from CuSO(4), 3) 10 mg of Cu/kg of DM from CuSO(4), 4) 5 mg of Cu/kg of DM from CuGly, and 5) 10 mg of Cu/kg of DM from CuGly. Steers were individually fed a corn silage-based diet (analyzed 8.2 mg of Cu/kg of DM), and supplemented with 2 mg of Mo/kg of diet DM and 0.15% S for 120 d (phase 1). Steers were then supplemented with 6 mg of Mo/kg of diet DM and 0.15% S for an additional 28 d (phase 2). Average daily gain and G:F were improved by Cu supplementation regardless of source (P = 0.01). Final ceruloplasmin, plasma Cu, and liver Cu values were greater (P < 0.05) in steers fed supplemental Cu compared with controls. Plasma Cu, liver Cu, and ceruloplasmin values were greater (P < 0.05) in steers supplemented with 10 mg of Cu/kg of DM vs. those supplemented with 5 mg of Cu/kg of DM. Based on multiple linear regression of final plasma Cu, liver Cu, and ceruloplasmin values on dietary Cu intake in phase 1 (2 mg of Mo/kg of DM), bioavailability of Cu from CuGly relative to CuSO(4) (100%) was 140 (P = 0.10), 131 (P = 0.12), and 140% (P = 0.01), respectively. Relative bio-availability of Cu from CuGly was greater than from CuSO(4) (P = 0.01; 144, 150, and 157%, based on plasma Cu, liver Cu, and ceruloplasmin, respectively) after supplementation of 6 mg of Mo/kg of DM for 28 d. Results of this study suggest that Cu from CuGly may be more available than CuSO(4) when supplemented to diets high in S and Mo.     

Effects of Pre-Weaning Vitamin E,Selenium, and Copper Supplementation on the Performance,Acute Phase Protein Concentration,and Immune Function of Stressed Beef Calves

Two experiments were conducted to determine the effects of pre-weaning vitamin E, Se, and Cu supplementation on performance and immune response in stressed calves. In Exp. 1, 71 Hereford x Angus calves were individually creep fed: 1) control supplement (CON), 2) control plus 500 IU vitamin E + 0.3 mg Se/kg DM (E), 3) control plus 10 mg Cu/kg DM (CU), or 4) a combination of E and CU treatments (ECU). In Exp. 2, 80 Hereford (Angus calves were individually creep fed: 1) control supplement (CON), 2) control plus 0.3 mg Se/kg DM (SE), 3) control plus 500 IU vitamin E + 0.3 mg Se/kg DM (LOWE), 4) control plus 1000 IU vitamin E + 0.3 mg Se/kg DM (MEDE), or 5) control plus 1500 IU vitamin E + 0.3 mg Se/kg DM (HIE). Treatments continued for 49 (Exp. 1) or 53 d (Exp. 2) prior to weaning. At weaning all calves were transported to feedlot facilities. In Exp. 1, vitamin E tended (P<0.09) to improve post-weaning ADG and reduce (P<0.06) plasma haptoglobin (Hp), but had no effect on plasma α-tocopherol. Dietary Cu tended to increase (P<0.01) liver Cu stores, and antibody titers to bovine viral diarrhea (BVD) were greater (P<0.04) at weaning in CU and E calves. In Exp. 2, vitamin E tended to increase serum α-tocopherol (P<0.06) and cortisol (P<0.08). Vitamin E and Se supplementation may improve post-weaning performance and decrease plasma Hp concentrations in stressed calves.     

Dietary copper effects on lipid metabolism, performance, and ruminal fermentation in finishing steers

Sixty Angus steers (391.1+/-6.1 kg) were used to determine the effects of dietary Cu concentration on lipid metabolism and ruminal fermentation. Steers were stratified by weight and randomly assigned to treatments. Treatments consisted of 0 (control), 10, or 20 mg of supplemental Cu (as CuSO4)/kg diet DM. Steers were housed in pens equipped with individual electronic Calan gate feeders. On d 86 and 92, ruminal fluid was collected from two steers/treatment for IVDMD determination. Equal numbers of steers per treatment were slaughtered after receiving the finishing diets for 96 or 112 d. Gain, feed intake, feed efficiency, IVDMD, and ruminal VFA molar proportions were not affected by Cu supplementation. Copper supplementation increased (P < .05) liver Cu concentrations, and steers supplemented with 20 mg Cu/kg DM had higher (P < .05) liver Cu concentrations than steers supplemented with 10 mg Cu/kg DM. Serum total cholesterol concentrations were reduced by d 56 and at subsequent sampling dates in steers receiving supplemental Cu. Longissimus muscle cholesterol concentrations were lower (P < .10) in steers supplemented with Cu. Backfat depth was less (P < .05) in steers receiving supplemental Cu, but marbling scores were similar across treatments. Unsaturated fatty acid composition of longissimus muscle was increased (P < .05) and saturated fatty acid composition tended (P < .12) to be reduced in Cu-supplemented steers. Polyunsaturated fatty acid concentrations were higher (P < .05) in steers receiving Cu. These results indicate that addition of 10 or 20 mg Cu/kg to a high-concentrate diet containing 4.9 mg Cu/kg DM alters lipid and cholesterol metabolism in steers but does not affect ruminal fermentation.     

The effects of low-copper diets with or without supplemental molybdenum on specific immune responses of stressed cattle

Angus bull calves (n = 42; 7 mo of age; 254 kg initial BW) were used to investigate the effects of dietary Cu and Mo on immune function of stressed cattle. Randomly selected calves (n = 22) were injected with 90 mg of Cu as Cu glycinate 28 d before weaning and castrated at weaning. These calves received 7.5 and 5 mg of supplemental Cu/kg of DM during a 41-d receiving phase and a 196-d growing phase, respectively. The remainder of the steers received no supplemental Cu during the experiment. Copper-supplemented steers had adequate Cu status at weaning, whereas unsupplemented calves were marginally Cu-deficient. Cell-mediated response to intradermal injection of phytohemagglutinin was not affected by dietary treatment during the receiving phase. During the growing phase, half of the steers in each Cu treatment were given 5 mg of supplemental Mo/kg of DM. Copper supplementation increased (P<.05) humoral response to ovalbumin injected on d 133 of the growing phase. On d 168 of the growing phase, calves receiving only supplemental Mo were severely Cu-deficient based on plasma and liver Cu concentrations. The other treatment groups had adequate Cu status. Before feeding on d 168 of the growing phase, half of the steers were loaded onto trailers and transported 2.5 h, and they remained on the trailers an additional 9.5 h. Humoral response to porcine erythrocytes (PRBC) and delayed-type hypersensitivity (DTH) to dinitrochlorobenzene was tested at the end of the stress period. There was a Cu x stress interaction for humoral response to PRBC, with Cu decreasing antibody titers in unstressed calves and increasing titers in stressed steers. Stressed steers had lower (P = .03) ADG during the 28 d following stress. The results of this study indicate that Cu deficiency and 5 mg of supplemental Mo/kg of DM do not dramatically alter the specific immunity of stressed cattle.     

Effects of inorganic and organic copper supplemented to first-calf cows on cow reproduction and calf health and performance

Two experiments were conducted to determine whether the supplementation of Cu in the organic or inorganic form to 2-yr-old cows, before and after calving, affects reproduction rate, calf health and performance, passive transfer of immunoglobulin, or liver and serum Cu concentrations compared with unsupplemented controls. Cows (n = 75 in 1997; n = 120 in 1998) were randomly assigned by estimated calving date and body condition score to one of three treatments: 1) Control, control; 2) Inorganic, inorganic Cu supplement (200 mg Cu from CuSO4); 3) Organic, organic Cu supplement (100 mg Cu from AvailaCu). In 1998, a fourth treatment was added; 4) CU-ZN, organic Cu and Zn (400 mg Zn from AvailaZn in the Organic diet). Cows were fed a hay-based diet and individually fed supplements for approximately 45 d before and 60 d after calving (approximately January 15 to May 15 each year). Liver biopsies were obtained from cows before supplementation began, and from cows and calves at 10 and 30 d after calving. Blood samples were obtained from both cows and calves at calving, and colostrum samples were collected for IgG and mineral content. Cow liver Cu concentrations before supplementation began were 58 mg/kg in 1997 and 40 mg/kg (DM basis) in 1998. By 10 d after calving, liver Cu concentrations of Control cows had decreased (P < 0.05) to 24 mg/kg (Cu deficient) in both years, whereas liver Cu concentrations of Cu-supplemented cows increased (P < 0.05) in both years. Calf liver Cu concentrations at 10 d of age were similar (P > 0.10) for all treatment groups. No differences (P > 0.10) were found in colostrum Cu concentrations, or in calf health among treatments. No differences (P > 0.10) were found in cow BW change, calf serum Cu concentrations, calf weaning weights, or in cow 60-d pregnancy rates among treatments in either year. In 1998, cows in the Organic group had higher (P < 0.05) 30-d pregnancy rate than Control cows. Neither serum samples nor placental tissue were reliable indicators of Cu status in cows. Feeding supplemental Cu (either inorganic, organic, or organic with extra Zn) to cows with liver Cu concentrations of approximately 50 mg/kg before calving did not improve cow 60-d pregnancy rates or the health and performance of their calves when compared with unsupplemented cows.     

An evaluation of anthelmintic properties,assessed using faecal nematode egg counts,of New Zealand native flax (Phormium tenax)

AIM: To investigate the anthelmintic properties of New Zealand native flax (Phormium tenax) for cattle, using a faecal egg count reduction test (FECRT).

METHODS: Twenty-six heifer calves with high (>300 epg) faecal nematode egg counts (FEC) were paired into two groups and fed either chopped flax leaves ad libitum, or barley straw at an equivalent dry matter (DM) rate, from Day 0–7; all were supplemented with 1.5 kg/head/day cereal feed supplement. On Days 8–10, all heifers were fed a common diet of 3.5 kg DM/ head/day barley straw and 1.5 kg/head/day cereal feed supplement. Heifers were weighed and faecal samples were collected on Days —6, 0, 7, and 10; samples were analysed in triplicate for FEC. The nutritive value of the flax and straw was analysed.

RESULTS: Both the flax and straw had low dry matter digestibility (DMD) and protein content. Although the flax-fed claves grew more than the controls, this may have been related to gut fill. Total daily faecal egg output was similar for flax and straw groups on Day 7 (14.7 vs 15.0 x 10⁶ eggs/day, respectively) and Day 10 (14.9 vs 15.1 x 10⁶ eggs/day, respectively). There was no difference in the change in FEC with time between the calves fed flax or straw diets.

CONCLUSION: Consumption of flax leaves did not reduce FEC in calves with a mixed nematode infection.     

Effects of copper supplementation on feedlot performance, carcass characteristics, and rumen sulfur metabolism of growing cattle fed diets containing 60% dried distillers grains

The effects of 3 supplemental Cu concentrations on feedlot performance, mineral absorption, carcass characteristics, and ruminal S metabolism of cattle fed diets containing 60% dried distillers grains with solubles (DDGS) were evaluated in 2 experiments. Experiment 1 was conducted with 84 Angus-cross yearling steers and heifers (initial BW = 238 ± 36 kg), which were blocked by gender and allocated to 12 pens. Supplemental dietary Cu (tribasic copper chloride) treatments were: 1) 0 mg Cu/kg diet DM, 2) 100 mg Cu/kg diet DM, 3) 200 mg Cu/kg diet DM. The remainder of the diet was DDGS (60%), grass hay (10%), pelleted soy hulls (15%), and a vitamin-mineral supplement (15%). Diets were offered ad libitum throughout the finishing phase (168 d). Three cattle from each pen (n = 36) were harvested on d 168 and carcass data and liver samples were collected. Copper supplementation did not affect ADG (P = 0.22). However, the nonsignificant trend for increased ADG and decreased DMI led to a linear increase (P = 0.02) feed efficiency (G:F = 0.167, 0.177, and 0.177 for 0, 100, and 200 mg Cu/kg diet DM, respectively). The apparent absorption of Cu decreased quadratically (P = 0.07) and the apparent absorption of Mn and Zn were decreased linearly (P = 0.03 and P = 0.05, respectively) with increased Cu supplementation. Cattle supplemented with 100 or 200 mg Cu/kg diet DM had greater liver Cu concentrations (P < 0.01) than cattle that were not supplemented with Cu. There were no treatment effects (P > 0.10) on HCW, LM area, USDA yield grade, backfat, or marbling score. Experiment 2 was conducted with 6 ruminally fistulated steers that were fed the same diets as in Exp 1 in a replicated 3 × 3 Latin Square design. Copper supplementation did not affect (P > 0.10) ruminal pH or liquid S(2-) concentrations in steers consuming 60% DDGS diets (total dietary S = 0.55%). From 3 to 9 h after feeding, H(2)S gas concentration was decreased in those cattle supplemented with 100 mg Cu/kg diet. Concentration of H(2)S gas did not differ among cattle supplemented with 0 or 200 mg Cu/kg diet DM on 60% DDGS diets. Supplemental Cu improved feed efficiency in cattle consuming diets containing 60% DDGS; however, effects of Cu on rumen S metabolism were minimal even when supplemented at twice the maximum tolerable limit for beef cattle (NRC, 2000).     

高铜对肉鸡肝线粒体膜通透性、脂类代谢及肝和肌肉铜含量的影响

选用1日龄健康AA肉鸡120只随机均分成4组,使用硫酸铜作为铜源,饲喂玉米-豆粕型基础日粮,对照组饲料铜含量为11mg/kg,3个试验高铜组饲料铜含量分别为110,220,330mg/kg,试验至60日龄结束,来探讨高铜日粮对肉鸡肝线粒体膜通透性、脂类代谢及肝和肌肉铜含量的影响。结果显示:(1)随着铜浓度的增加和/或饲养日龄的延长,线粒体膜通透性转换孔(Mitochondrial permeability transition pore,MPTP)逐渐扩大(P0.05);(2)血清总胆固醇(T-Ch)含量110,220mg/kg铜添加组低于对照组(P0.05),330mg/kg铜添加组极显著低于对照组(P0.01),而甘油三酯(TG)的含量在各高铜组均极显著低于对照组(P0.01);(3)与对照组相比,肝脏铜含量110,220mg/kg铜添加组有所增加(P0.05),330mg/kg铜添加组极显著增加(P0.01),肌肉中铜含量在各高铜组均极显著高于对照组(P0.01)。这说明高铜可造成肝线粒体不同程度的肿胀和损伤,改变肉鸡脂类的新陈代谢,明显增加肝和肌肉组织的铜含量。