The assessment of blood copper status in cattle: a comparison of measurements of caeruloplasmin and elemental copper in serum and plasma

AIM: To evaluate the effect of test, either copper (Cu) concentration or caeruloplasmin (CP) activity, and sample type, either serum or plasma, on the diagnosis of blood Cu status in cattle. METHODS: Paired serum and heparinised plasma samples taken from 125 cattle in 13 herds were tested for Cu concentration and CP activity. The individual results for serum Cu concentration and serum and plasma CP activities were compared with the plasma Cu concentration results, as were their diagnostic values as determined by reference ranges, i.e. 'marginal', 'adequate', 'excess'. RESULTS: The overall mean serum Cu concentration was 2.92 micromol/L lower than the mean plasma Cu concentration; however, there was significant variability between individual samples, and the 95% limits of agreement ranged from 0.44 micromol/L more to 6.28 micromol/L less. The relationship between CP activity and plasma Cu concentration was less variable; the 95% prediction interval for plasma Cu concentration from CP activity was +/- 2.8 micromol/L, and was unaffected by whether CP activity was measured in plasma or serum. Using the threshold currently recommended for 'marginal' status of <8.0 micromol/L for serum Cu concentration identified a significantly different population of cattle than a threshold of <9.0 micromol/L for plasma samples. Altering the threshold to <7.0 micromol/L for serum Cu concentration produced better agreement. For CP activity, a threshold of 15 IU/L for both serum and plasma identified the same population as a threshold of <9 micromol/L for plasma Cu concentration. CONCLUSIONS: Serum Cu concentration is not a suitable substitute for plasma Cu concentration for the detection of 'marginal' blood Cu status in cattle as the individual variability in the apparent loss of Cu during clotting is too great. In this study, CP activity, in both serum and plasma, was found to be a suitable substitute for the detection of 'marginal' blood Cu status. CLINICAL RELEVANCE: The use of serum Cu concentration rather than plasma Cu concentration in the diagnosis of Cu responsive disease in cattle needs to be re-evaluated as does the way in which individual sample results are used in such tests.     

An evaluation of the copper sequestrated during clotting in cattle: is it just caeruloplasmin?

In cattle, sequestration of copper (Cu) occurs during the clotting process so that serum Cu concentrations are markedly lower than plasma Cu. It has been suggested that all of the Cu lost during clotting is caeruloplasmin (CP). This study used paired samples from 125 cattle to assess whether this assumption was correct. The regression equations for plasma CP activity against plasma Cu concentration and serum CP against serum Cu had significantly different intercepts suggesting that at zero CP activity the amount of Cu remaining was dependent on sample type. Furthermore, the difference between serum and plasma Cu was unrelated to Cu status, whereas the difference between serum and plasma CP was related to Cu status. The regression equation for the loss of CP activity against change in Cu concentration had an intercept that was different from zero, indicating that a reduction in Cu concentration could occur even if CP activity was unaffected by clotting.     

An evaluation of the effect of clotting on the recovery of copper from caprine blood

In the goat, diagnosis of copper (Cu) deficiency is often based on measurement of Cu in serum or plasma. Previous research in cattle and sheep has shown that these values are not interchangeable, but data for goats have not been published. Paired serum and heparinised plasma samples taken from 119 goats in eight herds were tested for Cu concentration. Plasma and serum Cu were significantly correlated (r=0.95). On average serum Cu was 3.5 μmol/L lower than plasma Cu, but this difference was related to Cu status (r=0.45). Mean serum Cu concentration was 83% of plasma Cu, with the 95% limits of agreement ranging from 66% to 100%. Similar to cattle and sheep, individual variability in Cu loss during clotting is too great for serum Cu to be used as a measure of Cu status in goats.     

Copper deficiency in sheep: An assessment of the relationship between concentrations of copper in serum and plasma

AIM: To assess the relationship between concentrations of copper in serum and plasma in sheep.

METHODS: Concentrations of Cu were measured in paired serum and heparinised plasma samples collected from 110 sheep in nine flocks. Linear regression was used to evaluate whether flock or gender had a significant effect on the association between concentrations of Cu in serum and plasma. The individual results for concentrations of Cu in serum were then compared with those from plasma, using correlation and limits of agreement plotting.

RESULTS: Concentrations of Cu in serum ranged from 7.3 to 22 (mean 14.0) µmol/L, while concentrations in plasma ranged from 9 to 27 (mean 16.3) µmol/L. On average, concentrations of Cu in serum were 2.3 µmol/L lower than in plasma. Over the range of values seen in this study, concentrations of Cu in plasma and serum were significantly correlated (r=0.89), and mean concentrations in serum were 87% of those in plasma. There was no effect of flock or gender on the relationship between concentrations of Cu in serum and plasma. Despite the significant correlation, there was marked variability between individual samples in the proportion of Cu that was lost during clotting, with the 95% limits of agreement for serum Cu ranging from 70 to 104% of the plasma concentration.

CONCLUSIONS: As in cattle, the individual variability in the loss of Cu during clotting in sheep is too great for concentration of Cu in serum to be used as a substitute for that in plasma.

CLINICAL RELEVANCE: When assessing the blood Cu pool as part of the diagnosis of Cu-responsive disease in sheep, the concentration of Cu in plasma should be measured in preference to that of serum. We suggest that a range of 4.5 to 9 µmol/L in plasma be used to define marginal Cu status in sheep.     

An evaluation of the effect of clotting on the relationship between copper and caeruloplasmin in bovine blood

The ratio of caeruloplasmin activity to copper concentration (CP:Cu) has been suggested as a more accurate determinant of the requirement for additional copper than plasma or liver copper concentrations. Although this test has no peer-reviewed evidence of efficacy, it has been used by a large number of UK veterinarians. However, the available test uses a serum caeruloplasmin (sCP) activity to plasma copper (pCu) concentration ratio which, because of the preferential loss of caeruloplasmin during clotting, is likely to underestimate the true CP:Cu, although it has been suggested that the marginal range accounts for this. This study was undertaken to evaluate the effect of using serum copper (sCu) rather than pCu concentrations in calculating CP:Cu. Using sCu rather than pCu increased CP:Cu by more than was accounted for by the marginal range. Of 48 cattle which were reported as 'low' using sCP:pCu, 22 were 'normal' when sCu was used instead of pCu. All herds with 'marginal' or 'low' mean CP:Cu when the sCP:pCu concentration ratio was used had 'normal' ratios when sCu was used instead of pCu.     

Comparison of concentrations of copper in plasma and serum from farmed red deer (Cervus elaphus)

AIM: To determine the relationship between the concentrations of Cu in plasma and serum in red deer, and to compare this relationship with those previously reported in cattle and sheep.

METHODS: Paired serum and heparinised plasma samples from 114 red deer from 10 herds (n=6-20 per herd) were analysed for concentrations of Cu. Samples were collected either at slaughter (n=84; eight herds) or by jugular venepuncture (n=30; two herds). Thirty-nine of the samples taken at slaughter were from adult hinds from four herds, while other samples were taken from 10–14-month-old males, except for one herd (10 samples) where an equal number of 8–9-month-old males and females were sampled. The effect of age, gender and herd on the relationship between concentrations of Cu in plasma and serum was assessed using univariate ANOVA. The individual results for concentrations of Cu in serum were compared with those in plasma, using limits-of-agreement plotting.

RESULTS: The mean concentration of Cu in plasma was not significantly different from that of serum (0.048; 95% CI=-0.14 to 0.24 µmol/L). There was no effect of age, sex or herd on this relationship.

CONCLUSIONS: In deer, there was no significant difference between concentrations of Cu in plasma and serum regardless of age, sex or herd of origin.

CLINICAL RELEVANCE: In contrast to the situation in cattle and sheep, the concentration of Cu in serum can be used interchangeably with that in plasma for the estimation of concentration of Cu in blood of red deer.     

Minimal herd sample size for determination of blood copper status of cattle

Copper is required by cattle for synthesis of numerous proteins and enzymes. Copper deficiency in cattle results in a variety of signs ranging from weight loss to diarrhea. In the fall of 1984 and 1985, blood samples were collected from 22 cattle herds near Gunnison, Colo. Approximately one third of the herds were classified as copper deficient (ie, mean serum copper concentration less than 0.6 mg/L). The inherent variability of serum copper concentrations within a herd mandates the determination of the minimal number of cattle to be tested to properly assess the blood copper status of a herd. Coefficients of variation for serum copper concentration were used to calculate a minimal sample size, with a 95% confidence interval for each herd. Minimal sample size ranged from 3 to 55 cattle/herd (ie, 1 to 22% of the herd); this finding suggested that the usual procedure of testing 10% of the herd may be inappropriate.     

Copper,zinc, and iron concentrations in blood serum and diet of dairy cattle on semi-industrial farms in central Iran

The aim of this study was to evaluate the blood serum and diet concentrations of copper, zinc, and iron in Holstein dairy cattle kept under semi-industrial farming in Isfahan province, central Iran. Moreover, the effects of season, pregnancy, and daily milk yield on serum Cu, Zn, and Fe concentrations were also evaluated. The study was carried out on 12 semi-industrial Holstein dairy cattle farms. A total of 120 blood serum samples (60 in each season) and 24 diet samples (12 in each season) were collected in the summer and winter. The Cu, Fe, and Zn contents were assessed in samples using atomic absorption spectrophotometer. In the summer, the mean concentrations of Cu and Fe in serum samples were lower and higher than the critical level, respectively (P < 0.05). In total diet samples, the mean concentrations of Zn were significantly higher than critical level (P < 0.05). In summer, winter, and total diet samples, the mean concentrations of Fe were significantly higher than critical level (P < 0.05). The serum Cu and Zn concentrations were significantly higher in the winter than those determined in the summer (P < 0.05). The serum Cu concentrations were significantly higher in nonpregnant than those in pregnant dairy cattle (P < 0.05). No significant difference was observed in serum Cu, Zn, and Fe concentrations of dairy cattle in different daily milk yield groups. It can be concluded that Holstein dairy cattle reared under semi-industrial dairy farming were deficient in serum Cu concentrations, especially in summer. Further, high level of Fe in blood serum might be due to feeding of cattle with diet containing excess quantity of Fe.     

Relationship of serum and plasma copper and ceruloplasmin concentrations of cattle and the effects of whole blood sample storage

The present study was conducted to determine whether plasma and serum copper and ceruloplasmin concentrations in cattle are different and whether transport of samples with storage on ice before centrifugation affects the measurements. Mean copper and ceruloplasmin values were higher in plasma than in serum. Linear regressions were plasma copper (microgram/ml) = 1.200 serum copper -0.032 (r2 = 0.99), serum ceruloplasmin (mg/dl) = 14.0 serum copper + 2.34 (r2 = 0.48), and plasma ceruloplasmin (mg/dl) = 18.2 plasma copper + 2.1 (r2 = 0.43). The percentage of copper associated with ceruloplasmin was less in serum (55%) than in plasma (66%). Storage of blood samples on ice for 3 days decreased serum copper value by 3.5%. Linear regressions to correct for storage effects were corrected serum copper = 1.11 stored serum copper -0.04 (r2 = 0.94) and corrected plasma copper = 1.22 stored plasma copper -0.17 (r2 = 0.86). A cuproprotein may be involved in the blood clotting process, and some ceruloplasmin and its copper are apparently trapped in the fibrin clot, causing less copper in serum, compared with that in plasma. The difference between plasma and serum copper concentrations of calves was slightly increased by dietary copper supplementation.     

Bovine Subclinical Ketosis in Dairy Herds in Iran

Subclinical ketosis (SCK) is defined as elevated concentrations of ketone bodies in the absence of clinical signs of ketosis. It is an important metabolic disease in dairy cattle during early lactation and is associated with losses in milk production and several other periparturient diseases. Limited information is available regarding the prevalence of SCK in dairy herds in Iran. The objectives of this study were (i) to determine the incidence of SCK in the dairy herds in Kerman province of Iran using serum beta-hydroxybutyrate (BHB) concentrations, and (ii) to investigate the relationship between serum concentrations of BHB and glucose of cows with SCK. In the present study, 90 multiparous Holstein cows (4-6 years old) from 11 commercial dairy herds were evaluated 3-4 weeks after calving. The distribution of blood BHB concentrations seemed to suggest a cut-off point of 1200 micromol/L between cows with and without SCK. At this cut-off point, 14.4% of tested cows (13/90) were classified as subclinically ketotic, with the prevalence rate within herd ranging from 10% to 20%. Cows with SCK were detected in all the investigated dairies except one. Blood glucose concentrations in cows with SCK were significantly lower (p < or = 0.05) than in cows without SCK, and serum BHB and glucose concentration were inversely correlated (r = -0.43, p < or = 0.05). The results suggest that, using a cut-off of 1200 micromol/L, BHB concentrations can be used during early lactation for diagnosis and to make management decisions for prevention and treatment.     

Analysis of the value of measurement of the activity of caeruloplasmin as an alternative to measurement of the concentration of elemental copper in plasma and serum of farmed red deer

Abstract

AIM: To evaluate the relationship between the concentration of elemental Cu and activity of caeruloplasmin (CP) in the plasma and serum of farmed red deer (Cervus elaphus).

METHODS: Paired serum and heparinised plasma samples taken from 142 deer from 10 herds in the North Island of New Zealand were tested for the concentration of elemental Cu and activity of CP. Additionally, liver biopsy samples were taken from 49 of the deer (all one herd). The relationship between individual results for the concentration of elemental Cu and activity of CP was examined using a segmented model, with random slope and intercept and threshold.

RESULTS: The activity of CP in plasma and that in serum were strongly correlated (R²=0.994), with a high level of agreement. The concentration of Cu and activity of CP also showed a strong association (R²>0.88 for both plasma and serum), although there were significant differences between herds, with the segmented regression model providing the best fit rather than a linear mixed model.

Using the current thresholds for elemental Cu, the relationship between the concentration of Cu and activity of CP suggested that an activity of CP of <4 IU/L indicates Cu deficiency, and that deer with an activity of CP of ≥7 IU/L have adequate Cu status.

CONCLUSIONS: The relationship between elemental Cu and CP is markedly different from the simple linear relationship previously reported for cattle. Above a threshold of 10 IU/L, the rise in elemental Cu per unit increase in activity of CP was 50% of that below 10 IU/L. This is probably because above this threshold the oxidative activity of CP per enzyme unit was greater.

CLINICAL RELEVANCE: The association between concentration of Cu and activity of CP was robust enough to define provisional thresholds for determining Cu status. However, the proximity of the deficiency threshold to the limit of detection of the CP test, the effect of herd on the association, and the inherent disadvantages of using an enzymatic system, mean that activity of CP should not be used routinely to estimate Cu status in deer. When assessing the Cu status of deer based on blood samples, the concentration of Cu in plasma or serum should be used.     

Changes in plasma metabolic hormone concentrations during the ovarian cycles of Japanese black and holstein cattle

The aim of the present study was to investigate the changing profiles of plasma metabolic hormones during the ovarian cycles of beef and dairy cattle. We used 16 non-pregnant, non-lactating Japanese Black beef cattle (6 heifers and 10 cows; parity=2.3 +/- 0.8) and 12 multiparous Holstein dairy cows (parity=3.0 +/- 0.3). Blood samples for hormonal analysis (growth hormone, GH; insulin-like growth factor-I, IGF-1; insulin; and progesterone, P4) were obtained twice weekly for 40 days before artificial insemination for Japanese Black cattle and from 50 to 100 days postpartum for Holstein cows. Luteal phases were considered normal if the P4 concentrations for at least 3 time points over the course of 7 days remained above 1 ng/ml and at least 2 of the time points were above 2 ng/ml. The patterns of the ovarian cycles were classified into two types (normal or abnormal, such as having prolonged luteal phase and cessation of cyclicity) on the basis of the plasma P4 profiles. The plasma concentrations of IGF-1 in both breeds increased transiently during the preovulatory period when the P4 levels were low and decreased to lower levels during the luteal phase when the P4 levels were high. The plasma concentrations of insulin in the 3(rd) week of normal ovarian cycles when the plasma P4 concentration dropped to less than 1 ng/ml were higher than those at other time points in the Japanese Black cattle, but not in the Holstein cows. The plasma concentrations of GH did not change during the ovarian cycle in either breed. In conclusion, the present study indicates that the plasma IGF-1 concentration increases during the follicular phase (low P4 levels) and decreases during the luteal phase (high P4 levels) in non-lactating Japanese Black and lactating Holstein cattle. The results suggest that ovarian steroids, rather than nutrient status, may be related to the cyclic changes in IGF-1 secretion from the liver in cattle.     

Plasma concentration of estrone sulfate during pregnancy in different breeds of Japanese beef cattle

Plasma concentrations of estrone sulfate in different breeds of Japanese beef cattle and the relationship between those concentrations and feto-placental growth were examined in order to assess the possibility of monitoring abnormal growth of the fetus. Blood samples were obtained from cows from day 90 of gestation to parturition. The plasma concentration of estrone sulfate was measured by direct enzyme immunoassay. From day 180 of gestation, the mean concentration of estrone sulfate increased gradually and it was drastically elevated after day 240 of gestation with the maximum at day 285. Plasma concentrations of estrone sulfate on day 240 of gestation was significantly increased in F(1) cows (Holstein Friesian and Japanese Black) compared with those in other breeds of cow. From day 270 to 278 of gestation, estrone sulfate concentrations of Holstein Friesian cows inseminated by Holstein Friesian differed from those inseminated by Japanese Black. In the cow with retained placenta, the plasma concentration of estrone sulfate reached plateau at day 240 of gestation and did not increase thereafter. There was no significant relationship between estrone sulfate concentration and duration of gestation, calf birth weight, weight of placenta or viability of newborn calves. These results indicate that changes of plasma estrone sulfate concentration in Japanese beef cattle are very similar to those in Holstein dairy cattle. They also suggest that the plasma concentration of estrone sulfate is associated with the breed of pregnant cow and that its concentration is also affected by calf birth weight depending on the breed of bull. It seems possible to predict the incidence of retained placenta but not the calf birth weight and viability of newborn calves in Japanese beef cattle.     

Relationship between serum leptin concentrations and the marbling scores in Japanese Black Cattle

The objective of this study was to investigate the relationship between marbling and serum leptin concentrations. First, we compared serum leptin concentrations between Japanese Black cattle and Holstein calves, and found that the mean serum concentration was significantly higher (P < 0.05) in Japanese Black cattle (2.67 ± 0.41 ng/mL, n = 13) than in Holstein calves (1.79 ± 0.43 ng/mL, n = 5). We then examined the effects of roughage intake or vitamin A on the serum leptin concentrations in Japanese Black cattle. Although the leptin concentrations for the high roughage group were significantly higher than those for the low roughage group at 4, 7 and 20 months old, there was no significant difference in the carcass characteristics of the two groups. In addition, although there was a significant difference in the marbling score between the high vitamin A group and low vitamin A group, there was no significant difference in serum leptin concentrations between the groups. These results suggest that although serum leptin concentrations were not significantly correlated to the marbling scores they may be related to the genetic advantage for marbling in Japanese Black cattle.     

Digestibility and blood parameters in the preruminant calf fed a clotting or a nonclotting milk replacer

Eight male Holstein calves 7 to 10 d of age were fed a milk replacer containing a skim milk powder subjected to low-temperature drying either with or without addition of an oxalate-NaOH buffer known to prevent curd formation. The calves were used in a completely randomized design to study the effect of milk clotting on digestibility and blood parameters. Plasma glucose and plasma insulin were similar (P greater than .05) for the clotting and the nonclotting milk replacers. For both treatments, concentrations of glucose and insulin reached a peak 2 h postfeeding (P less than .01). Plasma triglycerides were higher (P less than .01) postfeeding for the nonclotting than for the clotting milk replacer. Plasma essential amino acids and plasma urea were higher, whereas plasma calcium was lower, for the nonclotting milk (P less than .01). Digestibility of dry matter, protein and fat was similar (P greater than .05) between clotting and nonclotting milk. The dry matter content of feces was not affected by clotting (P greater than .05). The data are interpreted to indicate that clotting of the milk replacer modifies blood concentrations of triglycerides, essential amino acids and urea without changing the digestibility of the diet.     

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.     

新西兰娟珊奶牛、荷斯坦奶牛与中国荷斯坦奶牛抗氧化指标比较

在相同的饲养管理条件下,在冬、夏两季随机抽取3种牛的血液样品,使用可见光分光光度法、原子吸收与荧光分光光度法,分别对3种牛的抗氧化指标T-SOD、Cu/Zn-SOD、GSH-Px、T-AOC、MDA以及血清微量元素Se、Cu、Zn、Mn进行系统测定与分析。试验结果表明:冬季,引进娟珊奶牛和荷斯坦奶牛的T-SOD、Cu/Zn-SOD、T-AOC、Cu、Zn、Mn均高于中国本地荷斯坦奶牛,差异显著(P<0.05),GSH-Px与本地荷斯坦奶牛比较差异不显著(P>0.05);夏季,引进娟珊奶牛、荷斯坦奶牛、本地荷斯坦奶牛的T-SOD、Cu/Zn-SOD、GSH-Px、Mn、Se差异不显著(P>0.05)。引进娟珊奶牛的T-AOC显著高于荷斯坦奶牛,差异显著(P<0.05);从对相同季节的分析可知,夏季引进娟珊奶牛,其适应性有一定的提高。     

Trace element metabolism, dietary requirements, diagnosis and prevention of deficiencies in deer

The first deer farms were established in New Zealand about 30 years ago. Extensive studies on trace elements in sheep and cattle have resulted in clarification of the requirements of those species and the development of protocols to diagnose and prevent deficiencies. In contrast, there have been very few studies conducted with deer. This review summarises information available on trace element nutrition of deer and concludes that, in New Zealand, cobalt (Co), vitamin B12, selenium (Se) and iodine (I) deficiencies are of lesser importance than copper (Cu), which can have a significant impact on deer health and performance. However, on individual farms, Se and I deficiency may cause significant production losses if not managed appropriately. There are no reports of production limitations caused by Co deficiency. Copper deficiency manifests itself as clinical disease, namely enzootic ataxia and osteochondrosis. Growth responses to Cu supplementation have only been reported in 2/11 trials and were not predicted from low serum and/or liver Cu concentrations. On the basis of clinical signs of Cu deficiency, the proposed reference ranges used to predict Cu status from serum Cu concentrations (micromol/l) are: 5, deficient; 5-8, marginal and; 8, adequate; and for liver Cu concentrations (micromol/kg fresh tissue) are: 60, deficient; 60-100, marginal and; 100, adequate. Copper supplementation strategies based on Cu-EDTA injections, Cu-oxide needles or the application of Cu to pasture are effective at increasing Cu status for varying periods. More recent research suggests that alternative forage species that have a high Cu content (10 mg/kg dry matter (DM), may play a role in the prevention of Cu deficiency.     

Copper oxide needles administered during early pregnancy improves the copper status of ewes and their lambs

AIM: To determine the effect of copper oxide (CuO) needles administered orally to ewes in early pregnancy on the copper (Cu) status of ewes throughout gestation and lactation, and of their lambs from birth to weaning. METHODS: In mid-April, after mating, 12 twin-bearing ewes were given an oral capsule containing 5 g CuO needles while 12 others served as untreated controls. Changes in Cu status were monitored by determining serum and liver Cu concentrations on Days 1, 62, 117, 153, 185 and 216 in the ewes, and at 1, 36, 68 and 99 days of age for lambs. Pasture herbage samples were collected at about 60-day intervals for Cu, molybdenum (Mo), iron (Fe) and sulphur (S) determinations. RESULTS: Copper status of the ewe flock was adequate, as initial mean serum and liver Cu concentrations were 15 micromol/L and 1,060 micromol/kg fresh tissue, respectively. The CuO needles did not affect serum Cu concentrations of the ewes or their lambs. Mean serum Cu concentration of all lambs at birth was about half that of ewes (8 vs 17 micromol/L), regardless of Cu supplementation, and not until at least 68 days of age was it similar to the dams'. Liver Cu concentrations of lambs at birth were also lower than that of the ewes (380 vs 640 micromol/kg fresh tissue among the controls), but changed little over time. CuO treatment increased liver Cu concentration in ewes for at least 185 days and in lambs for 36 days (p<0.05). Among untreated ewes, there was a seasonal decline in mean liver Cu concentrations, which were highest in autumn and lowest in early spring (1,060 vs 370 micromol/kg fresh tissue). The mean pasture mineral concentrations were Cu 5.7, Mo 0.48, Fe 194 and S 2,900 mg/kg dry matter (DM). CONCLUSIONS: CuO needles administered to ewes in early pregnancy increased their Cu status through gestation and early lactation, and the Cu status of their lambs for 36 days from birth. Serum Cu concentration was not affected by treatment but a marked rise was observed in all lambs between birth and 10 weeks of age. CLINICAL RELEVANCE: Copper deficiency in young lambs may be conveniently and effectively prevented by treating ewes with CuO needles during early pregnancy. The serum Cu concentration in lambs <8 weeks old may not reflect the Cu status of the flock.     

Secretion of dopamine and norepinephrine in hypophyseal portal blood and prolactin in peripheral blood of Holstein cattle

The objective was to test the hypothesis that dopamine regulates prolactin (PRL) secretion by determining acute changes in catecholamine concentrations in hypophyseal portal blood of cattle, and their relation to peripheral blood concentration of PRL in hypophyseal stalk-transected (HST) and sham-operated controls (SOC). Holstein heifers (606 +/- 21 kg BW; mean +/- SE) were subjected to neurosurgery for 8 h to collect hypophyseal portal blood with a stainless steel cannula designed with a cuff placed under the pituitary stalk and peripheral blood via a jugular vein catheter. PRL plasma concentration was measured by radioimmunoassay, and dopamine and norepinephrine in portal plasma by radioenzymatic assay. During anesthesia before HST or SOC, PRL plasma concentration ranged from 20-40 ng/ml throughout 255 min. PRL abruptly increased and remained above 90 ng/ml after HST compared with a steady decrease to <20 ng/ml in SOC heifers throughout 440 min. Within 5 min after severing the hypophyseal stalk, dopamine in portal blood (>8 ng/ml) was significantly increased (P < 0.05) compared with peripheral blood (<2 ng/ml). Norepinephrine concentration in portal blood was significantly greater (P < 0.05) than in peripheral blood during the first 60 min. The sustained high PRL level in peripheral plasma after severing the hypophyseal stalk stimulated hypothalamic dopamine secretion from hypophyseal portal vessels during the prolonged period of blood collection. Norepinephrine concentration in these cattle was greater in hypophyseal portal than in peripheral blood, implicating both an important hypothalamic source of the catecholamine as well as an adrenal gland contribution during anesthesia.