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N F Suttle

Publications and source records attributed to N F Suttle.

At least 19 recordsLinked to original sources
PubMed2003

Predicting the risk of cobalt deprivation in grazing livestock from soil composition data.

The objective was to derive predictive equations for acetic acid-extractable cobalt (A-ECo) in soils so that extensive national databases for total (T) Co in soils and stream sediments could be converted to 'plant available' concentrations for the purpose of predicting risk of Co deficiency in grazing livestock. Data on the chemical and physical properties of 103 soils from 15 different parent materials and 54 soil series in England and Wales were used. Ranges for the mean values for parent materials were: TCo, 5.0-20.4 and A-ECo, 0.20-1.30 mg kg-1; percentage (P) A-ECo, 3.4-13.5; soil manganese (Mn) 268-1174 mg kgDM-1; pH, 3.7-8.0. There were significant effects of parent material on all parameters with Chalks, Old and New Red Sandstones particularly low in A-ECo. Multiple linear regression yielded the following equation for predicting A-ECo, which accounted for 56% of the variance with 12 outliers, including the lowest pH values, omitted: [figure: see text] REML was used on the complete, unbalanced, log-transformed data set to fit a Generalised Mixed Model with parent material as random effect and soil Mn and pH as fixed effects; the effect of parent material was no longer significant. It was concluded that A-ECo can be satisfactorily predicted for most soils in England and Wales from TCo, TMn and soil pH.

Animal Feed↗
PubMed2003

The effects of breed, neonatal age and pregnancy on the plasma copper status of goats in Oman.

There is a history of copper deficiency in grazing Omani livestock and the copper status of three economically important goat breeds, Jabal Akhdar (JA), Batina (B) and Dhofari (D) were therefore compared in October/November (cool season) and June (dry season) in a penned flock given a plentiful dietary supply of copper. In the cool season, 62 lactating does (5 JA, 12 B and 33 D), their 0-5-day-old kids (17 JA, 19 B and 22 D) and 25 dry does (17 JA, 5 B and 3 D) were blood sampled. In the dry season, the does sampled were either barren (15 JA, 16 B and 13 D) or pregnant (9 JA, 13 B and 33 D). The samples were analysed for total copper (TCu) and trichloroacetic acid (TCA)-soluble copper (TCA-sol Cu). There were no effects of breed on TCu or TCA-sol Cu in the cool season, the overall means being 0.75 (SE 0.049) and 0.59 (SE 0.052) mg/L. The mean TCu was low in kids at birth (0.59 mg/L) but had increased to 0.86 mg/L by 4 days of age (p < 0.001); breed differences were found (p < 0.002), the pooled values for JA, B and D being 0.77, 0.59 and 0.68 (SE 0.033-0.044) mg/L, respectively. By the dry season, the mean TCu had risen in barren does to 0.96 (0.045) mg/L but not in pregnant does (0.76 (0.047) mg/L: p < 0.002) and breed differences had emerged, the mean for D being 20% lower than those for JA and B (p < 0.05). The highest TCu values were found in the 7-month-old kids in June ( 1.17 (0.039) mg/L) but the breeds did not then differ. Some effects on TCA solubility were found but were considered unreliable. Breed effects may have been diminished by the generous supply of copper and early stage of lactation studied.

Age Factors↗
PubMed1992

Effects of dietary molybdenum on nematode and host during Trichostrongylus vitrinus infection in lambs.

The addition of molybdenum (0.05 mmol kg-1 dry matter) to the diet of lambs exposed for four weeks to a trickle (2500 third stage larvae per day) infection with Trichostrongylus vitrinus reduced the number and length of adult worms retrieved from the small intestine 11 days later: both effects were particularly marked in female worms from female lambs (P less than 0.01). Worms from lambs given molybdenum contained less proteinase enzyme activity and secreted less proteinases in culture irrespective of the sex of the host. Pathogenicity was not attenuated by molybdenum. Damage to the intestinal mucosa was severe in both dietary groups but infected females given molybdenum developed lower plasma albumin concentrations and lighter dressed carcases than those not given molybdenum. Neither the effects on the parasite nor those on the host could be attributed simply to molybdenum-induced copper depletion, using conventional measures of copper status. Molybdenum may be toxic to T vitrinus but may also facilitate or enhance the inflammatory process limiting larval establishment or increasing parasite rejection.

Administration, Oral↗
PubMed1992

Effects of dietary molybdenum on nematode and host during Haemonchus contortus infection in lambs.

The addition of molybdenum (0.05 mmol kg-1 dry-matter) to the diet of lambs given a trickle infection of Haemonchus contortus larvae (500 third stage larvae d-1 over six weeks) reduced mean faecal egg counts (epg) from 3952 to 2312 +/- 402 by 32 days (P less than 0.02) and greatly reduced the mean number of worms recovered from the abomasum 14 days after infection ceased (907 compared with 4167: P less than 0.01). Infection reduced haemoglobin concentrations less in lambs given molybdenum although the difference was small relative to the reduction in worm burden. Lambs not given molybdenum had low intraepithelial mast cell counts in the abomasal mucosa and less abomasal hypertrophy than expected from abomasal parasitism. Molybdenum did not consistently reduce the copper status of the host or the parasite. Previous exposure to molybdenum greatly reduced protein but not proteinase activity in, or secreted by, adult worms cultured for eight hours. It is suggested that molybdenum either increased the inflammatory response which preceded worm rejection or that it indirectly enhanced that reaction by reducing the effectiveness of copper-dependent, anti-inflammatory enzymes in the gastrointestinal mucosa.

Abomasum↗
PubMed1989

Recent developments in trace element metabolism and function: trace elements, disease resistance and immune responsiveness in ruminants.

Evidence for the influence of trace elements on disease resistance in ruminants is reviewed with emphasis on susceptibility to infection in vivo during the more common deficiencies (copper, selenium and cobalt). Copper deficiency associated with increases in pasture molybdenum increased the susceptibility of lambs to microbial infections. Under experimental conditions, dietary molybdenum decreased the establishment of abomasal and intestinal nematodes but not their pathogenicity to lambs. Molybdenum may enhance inflammatory responses leading to parasite rejection by the host. Decreased incidence of metritis in selenium-treated dairy cows provides a rare example of an association between selenium deficiency and decreased disease resistance. Improved antibody responses following selenium administration have also been found in sheep. Cobalt deficiency has reduced lamb survival and increased susceptibility to parasitic infection transiently in cattle and lastingly in sheep. In copper-, selenium- or cobalt-deficient sheep and cattle, there are many reports of impaired leucocyte and lymphocyte responses to in vitro challenges, but their relevance to disease resistance in vivo is unproven. Disease resistance may have priority for limited micronutrient supplies, leaving other processes vulnerable.

Animals↗
PubMed1988

An assessment of the efficacy and safety of selenium and cobalt included in an anthelmintic for sheep.

A trial was devised to assess whether the administration of selenium and cobalt together with the anthelmintic mebendazole (Ovitelmin S&C) was safe and could improve the supplies of selenium and cobalt for adult sheep fed a whole grain diet, low in both elements, which produced a steady decrease in blood glutathione peroxidase (GSHPx) and plasma vitamin B12 concentrations. Ovitelmin S&C, when given orally in a single dose as a suspension containing 0.34 mg selenium/ml, and 0.44 mg cobalt/ml (to provide 0.11 mg selenium and 0.15 mg cobalt/kg liveweight) significantly increased the GSHPx activity in blood. After a second dose given 28 days later the rate of change increased from 2.5 to 3.5 u/g haemoglobin/day. The responses in GSHPx were similar for a preparation which contained twice the concentration of selenium. Ovitelmin S&C increased the concentration of vitamin B12 in the plasma by about 1000 pg/ml for four to seven days after each dose and the increases were similar to those observed in sheep treated with an Ovitelmin preparation containing 45 times more cobalt (providing 6.7 mg cobalt/kg liveweight). After 63 days, liver vitamin B12 concentrations were 43 per cent higher in the cobalt treated than in the untreated groups (P less than 0.01) with no differences among the groups given cobalt. Neither adverse reactions nor signs of toxicity followed the administration of Ovitelmin S&C or Ovitelmin containing the higher concentrations of selenium and cobalt.

Administration, Oral↗
PubMed1987

Heinz body anaemia in lambs with deficiencies of copper or selenium.

1. The progression of Heinz body anaemia was studied in groups of lambs of low- and high-copper status, produced through breeding or Cu supplementation, when they were transferred from improved pasture to rape (Brassica napus L.) in autumn. Some lambs had previously received selenium by injection. The Cu and Se supplements markedly increased superoxide dismutase (EC 1.15.1.1; SOD) and glutathione peroxidase (EC 1.11.1.9; GSHPx) activities respectively in the erythrocytes, and both supplements had elicited growth responses at pasture. 2. At the time of transfer to rape, lambs not treated with Cu had lower whole-blood haemoglobin (Hb) concentrations and a higher percentage of erythrocytes containing Heinz bodies (6.6 v. 3.7%, P less than 0.01) than Cu-treated lambs: the corresponding effects of Se treatment were similar in direction but lower in magnitude (P less than 0.05). 3. After grazing rape for 2 weeks the mean Hb concentration had fallen by 30 g/l while Heinz body count had increased from 5 to 25%. However, counts were negatively correlated with the initial values and were unaffected by the Cu and Se treatments which maintained high plasma Cu concentrations and SOD and GSHPx activities. 4. The results provide the first evidence that Cu deficiency can induce Heinz body formation and the anaemia in grazing Cu-deficient lambs may be partly haemolytic in origin. The concomitant Se deficiency added marginally to the problem but neither the separate nor combined deficiencies increased the susceptibility of lambs to brassica anaemia.

Anemia, Hemolytic↗
PubMed1987

Safety and effectiveness of cupric oxide particles for increasing liver copper stores in sheep.

Five groups of four, housed Cheviot ewes (mean live-weight 50 kg) were given single doses of 0, 2.5, 5, 10 or 20 g cupric oxide particles in gelatin capsules while receiving a diet of marginal copper content based on pelleted oats. After 65 days liver copper concentrations had increased curvilinearly in relation to dose and all ewes given 10 or 20 g cupric oxide particles showed increases of at least 13.4 mmol kg-1 dry matter (850 ppm). Liver copper concentrations had generally declined after 85 days but biochemical and histological evidence of copper toxicity was recorded in one ewe which had received 20 g cupric oxide particles. Despite marked variations between individual sheep a dose of 0.1 g kg-1 liveweight (5 g) was considered to be safe and did not induce clinical copper toxicity in five sheep of the susceptible North Ronaldsay breed given the same basal diet.

Administration, Oral↗
PubMed1987

Safety and effectiveness of cupric oxide particles for increasing liver copper stores in cattle.

Five groups of three or four crossbred steers, mean initial liveweight 220 kg, were given a diet of barley and hay ad libitum. Each animal received a single oral dose of 0, 5, 10, 20 or 40 g cupric oxide particles. A dose of 5 g cupric oxide particles increased liver copper stores for about 240 days and higher doses increased liver stores for longer but 40 g was no more effective than 20 g (85 mg kg-1 liveweight). Variation among individuals was marked but the highest liver copper concentration recorded (7.59 mmol kg-1 dry matter) produced no biochemical evidence of copper toxicity. Earlier, cupric oxide particles were separated into three fractions, clumps, short rods and long rods and 5 mg kg-1 liveweight of each fraction given to steers of 173 kg mean liveweight. The form of the particles did not affect either their retention in the alimentary tract or the accumulation of copper in the liver.

Administration, Oral↗
PubMed1986

Copper deficiency in ruminants; recent developments.

The aetiology of copper deficiency in grazing ruminants has been clarified by a number of recent discoveries: the low availability of copper in lush grazed pasture compared with conserved forage; the inhibitory effects on absorption of small increases in herbage molybdenum and sulphur and the antagonism from iron ingested in soil; and the wide genetic variation in copper absorption between different breeds of sheep. The economic importance of copper deficiency has been emphasised by the discovery of unsuspected causes of loss: increased susceptibility to infection and growth retardation in lambs and infertility in cattle. The diagnosis of functional copper deficiency has been improved by the addition of erythrocyte superoxide dismutase to the assays of copper status.

Animals↗
PubMed1986

Problems in the diagnosis and anticipation of trace element deficiencies in grazing livestock.

Three principles governing the interpretation of biochemical criteria of trace element status are identified; they concern the relationships between the concentration of the marker and the intake of the element, the time on an adequate regimen and disturbances of tissue function. From these principles, the concentrations of liver copper, liver vitamin B12 and ovine serum vitamin B12 are shown to be insensitive indices of deficiency but good indices of surfeit. Plasma copper less than 9 mumol/litre is a good index of marginally deficiency but values may have to fall below 3 mumol/litre before there is risk of dysfunction and loss of production in sheep and cattle. Serum vitamin B12 values below 188 pmol/litre are indicative of functional deficiency in sheep whereas cattle with values between 38 and 76 pmol/litre may be only marginally deficient. Concentrations of methylmalonic acid in the plasma greater than 5 mumol/litre may offer a surer guide to diagnosis of functional vitamin B12 deficiency. Blood selenium or glutathione peroxidase concentrations may be unreliable in diagnosing selenium-responsive conditions because other nutrients determine what is adequate. For all elements the surest diagnosis is an improvement in growth or health in response to a specific supplement. The adoption of preventive measures should be prompted by biochemical evidence of marginal deficiencies in animals (rather than soils or pastures) although economic responses will not necessarily follow.

Animals↗
PubMed1986

Abnormal fermentations in continuous cultures of rumen micro-organisms given cobalt-deficient hay or barley as the food substrate.

1. Four experiments, each with four concurrent continuous cultures of rumen micro-organisms, were used to investigate the effects of inoculum, food substrate and cobalt supplementation on the course of fermentation and vitamin B12 synthesis. The inocula came from sheep receiving either a Co-rich, complete diet (Ruminant A: Expts 1, 2 and 4) or a Co-deficient hay (Expt 3). In Expt 2, inocula from different donors were used for each culture but for other experiments they were pooled. Co-deficient hay was used as the initial substrate and Co-supplements were given after 8-54 d Co-depletion. 2. In three of four experiments, two using a pooled inoculum, uncharacteristically low acetate (Ac) and high propionate (Pr) outputs were obtained from the hay substrate in some cultures. In all, six cultures gave Ac:Pr values in the effluent less than 2:1 and, in Expt 3, the differences remained evident for at least 6 d after a change to a Co-deficient barley substrate. 3. Abnormal cultures gave lower cobalamin (cbl) and vitamin B12 analogue outputs than normal cultures: when supplemented with Co they showed small responses in cbl and large responses in analogue output with a slow increase in Ac:Pr. 4. We suggest that the use of Co-deficient substrates led to shifts in the microbial populations of some cultures, indicating the cbl-dependence of some species of rumen micro-organisms.

Animals↗