Selenium and vitamin E in blood sera of cows from farms with increased incidence of disease

Selenium and vitamin E concentrations were measured in the blood sera of 287 cows in 91 herds. Herds with chronic mastitis and muscle diseases had significantly lower selenium concentrations (10.4 +/- 5.26 and 11.7 +/- 8.63 micrograms/litre serum, respectively) than healthy control herds (17.7 +/- 15.00 micrograms/litre). The selenium concentrations in herds with low fertility did not differ from control herds. The vitamin E concentrations were similar in all the herds. Supplementation of the mineral mixture with 20 mg sodium selenite and 2 g vitamin E/kg on 15 farms with a deficient selenium supply increased the selenium concentrations in the blood within two months in 12 of the herds. The vitamin E concentrations were hardly influenced by the supplementation.     

Vitamin E and selenium concentrations in month-old beef calves.

Three groups of beef cow and calf pairs were studied to determine plasma vitamin E and blood selenium (Se) concentrations of calves at 1 month old. Group 1 was managed on irrigated pasture and calves received no Se/vitamin E injections at birth. Group 2 was managed on irrigated pasture, and the calves were injected with Se/vitamin E at birth. Group 3 was managed on dry foothill grasslands, and these cows were supplemented with 56.3 mg vitamin E and 3 mg Se daily, and the calves received a Se/vitamin E injection at birth. The plasma concentration of vitamin E in group 1 and 2 cows (9.5 +/- 1.24 and 8.43 +/- 1.0 microg/ml, respectively) was significantly higher than that of the group 3 cows (2.28 +/- 0.42 microg/ml; P < 0.05). The blood Se concentrations in group 3 cows (169 +/- 37 ng/ml) were significantly higher than those in group 1 and 2 cows (36.4 +/- 15.9 and 31.1 +/- 12.5 ng/ml, respectively; P < 0.05). Calf Se was highly correlated to cow Se (r = 0.965), and calf vitamin E was moderately correlated to cow vitamin E (r = 0.605). Calf vitamin E concentrations were consistently lower than cow vitamin E concentrations, and many values would be considered deficient.     

维生素E和硒对奶牛乳房炎的作用

维生素E和微量元素硒是重要的抗氧化物质,在保护机体方面有着不可替代的作用。越来越多的研究表明,奶牛乳房炎的发生与机体维生素E和硒（Se）的缺乏有关。本文综述了维生素E和Se在降低奶牛乳房炎发病率中的作用。     

Effect of vitamin E supplementation on the health and fertility of dairy cows: a review

The currently recommended intake of vitamin E for dairy cows is based on the prevention of nutritional myopathy, a calf disease. However, it is likely that the vitamin E requirement of the modern dairy cow is very different from that of a calf. This review of the literature investigates the effect of vitamin E supplementation on the health and fertility of the dairy cow. Supplementation of high levels of vitamin E (at least 1000 iu per day) during the dry period and early lactation can reduce the incidence of mastitis, possibly because of an increase in immune system activity and function, but there appears to be little benefit of supplementation on infectious diseases other than mastitis. The evidence for a response in the reproductive system is more equivocal. In herds with a history of selenium deficiency and a high incidence of retained fetal membranes, supplementation, in conjunction with selenium, can reduce retention, but the evidence for an effect of supplementation on other reproductive diseases, such as cystic ovarian disease and metritis, is based on a very limited number of cases. The literature suggests that the current recommendations for vitamin E are inadequate. In particular, it suggests that the current linking of requirement to dry matter intake is incorrect, because vitamin E requirement is probably at its highest when intake is at its lowest However, the majority of the data on which this conclusion is based, come from North America where cows will encounter significantly different levels of oxidative stress from cows in the EU.     

National intervention study of mastitis control in dairy herds in England and Wales

An intervention study was carried out on 52 dairy farms in England and Wales to determine whether the implementation of a well-specified mastitis control plan in herds with an incidence of clinical mastitis of more than 35 cases per 100 cows per year would reduce the incidence of clinical mastitis, and also reduce the incidence of increases in the somatic cell counts of individual cows. A clearly defined plan for the diagnosis and control of mastitis was developed by two veterinary specialists from the research literature. The herds were randomly allocated to receive the plan either at the start of the study (intervention herds) or after one year (control herds). Data on mastitis management and the farm environment were collected during farm visits. After one year there was a significant 22 per cent reduction in the proportion of cows affected with clinical mastitis on the intervention farms compared with the control farms. There were also significant reductions of approximately 20 per cent in the incidence of clinical mastitis and in the occurrence of increases in the somatic cell counts of individual cows from below, to above 200,000 cells/ml.     

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.     

Blood selenium associated with health and fertility in Norwegian dairy herds

A survey of blood selenium (Se) concentrations in Norwegian Red heifers and dry period cows was conducted to reveal possible association to management, feeding, health and fertility. Selenium contents were determined in 254 herd blood samples consisting of pooled samples from individual non-lactating animals from herds in 5 counties. The Se concentrations showed a normal distribution with mean 0.09 microg Se/g blood, with a standard deviation (SD) of 0.05, and ranged from 0.02 to 0.23 microg/g, with 50 % of the samples being between 0.06 and 0.11 microg/g. The herds with Se concentrations below 0.06 microg/g were smaller (21.4 +/- 8.7 cow-years) than those with Se levels above 0.11 microg/g (27.5 +/- 14.1 cow-years) (P<0.01), but there were no differences in milk yield, incidence of replacement, proportion of animal culling, amount of concentrate or grass silage as percentage of energy consumption between the groups. Treatment registration records showed a tendency that more animals in the low Se herds were treated for all the diseases included in this investigation (64.8 animals per 100 cow-years) than those in the high Se herds (57.5 per 100 cow-years), while no such differences were revealed for individual disorders. There was, however, a significant difference in bulk milk somatic cell counts (BMSCC) between low and high Se herds, their values being 137 000 and 155 000 cells/ml, respectively. This difference was significantly influenced by herd size. Furthermore, a total of 4916 lactations were analyzed from individual health and fertility recordings, including 2 934 first lactations and 1 982 later lactations. The present study revealed a reduced incidence of disease treatment with increased Se concentrations from 0.02 to 0.23 microg Se/g blood. In this regard, there seemed to be an optimum of 0.10 to 0.15 microg Se/g for all types of mastitis treatments summarized, and for treatment of retained placenta. Thus, herd Se concentrations below and above these values was connected with increased probability for sum mastitis and retained placenta, reflecting the effect of the quadratic term of Se. The cow (composite) milk somatic cell count (SCC) was lower in lactations from low Se herds than in high Se herds with a marked SCC increase in the Se concentration interval from 0.11-0.13 microg/g blood. In conclusion, heifers and dry period cows in Norway are low in blood Se content and there seems to be a positive association between increased blood Se concentration pre partum and decreased incidence of mastitis, ovarian cysts and anoestrus/silent oestrus post partum.     

The Influences of Dietary Selenium and Vitamin E Intakes on Milk Somatic Cell Counts and Mastitis in Cows

Dietary supplements of selenium and vitamin E in greater amounts than are required for nutritional adequacy can have complementary functions in reducing somatic cell counts and both the severity and duration of clinical mastitis. Selenium inadequacy is geographically widespread and can frequently be a year-round problem. In contrast, an adequate intake of fresh grass and quality grass silage or other green, leafy material should provide adequate vitamin E. Many observations indicate that in farm situations where there is good udder hygiene and where long-acting antibiotic treatment is given at drying off, significant correlations are found between the mean bulk milk somatic cell counts and the blood selenium concentration or glutathione peroxidase activity in the blood, even where plasma vitamin E concentration is fully adequate. The accompanying reduced incidence of clinically affected quarters diminishes the need for corrective antibiotic treatment during lactation. Presentation of selenium and vitamin E within a sustained-release rumen bolus system during the dry period and into the succeeding lactation is a convenient means of supplementation to avoid over- or under-consumption by individual cows within a group. Adequate hygiene of the environment, the milking equipment and the udder are essential.     

Metabolic parameters and blood leukocyte profiles in cows from herds with high or low mastitis incidence

The objective of this study was to determine whether there were differences in metabolic parameters and blood leukocyte profiles between cows in herds with high or low yearly mastitis incidence. In this study, 271 cows from 20 high yielding dairy herds were examined. According to the selection criteria, all herds had low somatic cell counts. Ten of the selected herds represented low mastitis treatment incidence (LMI) and ten herds had high mastitis treatment incidence (HMI). The farms were visited once and blood samples were taken from each cow that was in the interval from three weeks before to 15 weeks after parturition. The eosinophil count was significantly lower among cows from the HMI herds in the period from four weeks to 15 weeks after parturition. The plasma concentrations of beta-hydroxybutyrate, glucose, insulin and urea did not differ between groups, but the concentration of nonesterified fatty acids was significantly higher among HMI cows during the period three weeks after parturition. The concentration of the amino acid tryptophan in plasma was significantly lower among the HMI cows prior to parturition. Glutamine was significantly lower in cows from HMI herds during the first three weeks after parturition. Arginine was consistently lower in HMI cows, although the decrease was only significant during the period from four to fifteen weeks after parturition. The results suggest that there were differences in the metabolism and immune status between herds with high or low yearly mastitis treatment incidence indicating an increased metabolic stress in HMI cows.     

Incidence and types of clinical mastitis in dairy herds with high and low somatic cell counts

Eighteen dairy herds were studied, 12 with a 12-month Dairy Herd Improvement Association herd mean somatic cell count (SCC) less than or equal to 150,000 cells/ml (low SCC) and 6 with a 12-month mean SCC greater than 700,000 cells/ml (high SCC). At the outset of the study, quarter samples for bacteriologic culture were collected (in duplicate) from all quarters of all lactating cows (whole herd culture). Subsequently, quarter milk samples for culture from all cows with clinical mastitis were collected for a period of 6 months. In the herds with low SCC, results of whole herd culture revealed low prevalence of intramammary infection attributable to all major pathogens (less than 4% of all quarters). Prevalence of infection with Streptococcus agalactiae (22.2% of all quarters) and Staphylococcus aureus (6.6% of all quarters) was significantly (P less than 0.05) higher in the herds with high SCC. Mean incidence of clinical mastitis in the herds with low SCC was 4.23 infections/100 cows/month (range, 0.42 to 10.25 infections). In the herds with high SCC, mean incidence was 2.91 infections/100 cows/month (range, 1.33 to 3.92 infections). In the herds with low SCC, infection type, as mean percentage of total clinically infected quarters sampled for culture/herd, was 0.0%, 2.2%, 12.3%, 43.5%, and 28.6% for Str agalactiae, S aureus, streptococci other than Str agalactiae, coliforms, and organisms not isolated, respectively. Respective percentages for the herds with high SCC were 41.5%, 18.3%, 12.6%, 8.0%, and 8.8%. During the study period (from April through January), incidence of clinical mastitis and clinical mastitis caused by coliform bacteria were highest in July and August for herds with low SCC.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparative efficacy of three dry-cow antibiotic formulations in spring-calving New Zealand dairy cows

AIM: To evaluate the efficacy of a dry-cow antibiotic preparation containing cloxacillin plus ampicillin in a formulation that gives a 10-week duration of action, in comparison to products containing cephalonium (10-week action) or cloxacillin alone (7-week action). METHODS: A total of 493 cows were selected from 6 spring-calving dairy herds in the Manawatu region of New Zealand, according to the criteria of the SAMM plan, to receive intramammary antibiotic therapy at the end of lactation (drying off). Cows were randomly allocated to receive 1 of the 3 dry-cow antibiotic products under investigation. Cows were examined twice during the dry period and twice daily during the first 10 days of their subsequent lactation for the presence of mastitis. Milk samples were collected from individual quarters at the time of drying off and at 7 and 28-35 days after calving, for determination of milk somatic cell counts (SCC). Bacteriology was carried out on milk samples taken from cows that developed mastitis during the first 10 days after calving. RESULTS: No cows developed mastitis during the dry period. Sixteen cows developed clinical mastitis within 10 days of calving; there was no difference in incidence between treatments. Streptococcus uberis was the most commonly isolated organism. Mean SCC on Day 7 were lower (p = 0.019) in cephalonium-treated quarters (189.9+/-28.4 x 10(3) cells/ml) than in cloxacillin-treated quarters (388.7+/-71.2 x 10(3) cells/ml); values in quarters receiving cloxacillin plus ampicillin were intermediate (252.0+/-47.0 x 10(3) cells/ml). SCC were similar between treatment groups on Day 28-35. CONCLUSIONS: The use of a combination of cloxacillin plus ampicillin was effective for the prevention of mastitis during the dry and peri-calving-periods in pastured dairy cattle.     

Intramammary infections and risk factors for clinical mastitis in herds with low somatic cell counts in bulk milk

Ten herds with low somatic cell counts in bulk milk had an incidence of clinical mastitis of only 2.2 per 100 cows whereas 10 other herds with similarly low cell counts had an incidence of 53.6 per 100 cows. The major pathogens in the herds with a high incidence were Escherichia coli, Streptococcus uberis, Staphylococcus aureus and the coagulase-negative staphylococci. The percentage of uninfected quarters in the herds with a high incidence of clinical mastitis was 21.4 per cent compared with 12.2 per cent in the herds with a low incidence of clinical mastitis. The prevalence of coagulase-negative staphylococci, Corynebacterium bovis and Micrococcus species was higher in the herds with a low incidence of clinical mastitis. There was a significant linear relationship between the percentage of uninfected quarters and the incidence of clinical mastitis in the herds with a high incidence of clinical mastitis. In herds with a low incidence of clinical mastitis significantly less teat disinfection after milking was practised. The results suggest that infections with minor pathogens tend to protect cows against mastitis, and that teat disinfection after milking may increase the percentage of uninfected quarters and lead to an increased risk of clinical mastitis in herds with low somatic cell counts in bulk milk.     

Costs associated with selected preventive practices and with episodes of clinical mastitis in nine herds with low somatic cell counts

Nine dairy herds (mean size, 149 cows) with bulk-tank milk somatic cell counts of less than 300,000 cells/ml and greater than 80% of cows with Dairy Herd Improvement Association linear somatic cell counts less than or equal to 4 were selected for study. Each herd was monitored for 12 consecutive months. Duplicate quarter-milk specimens were collected from each cow for bacteriologic culturing at beginning of lactation, cessation of lactation, and at the time of each clinical episode of mastitis. Streptococcus agalactiae was never isolated and Staphylococcus aureus was isolated from less than 1% of all quarters. There were 554 episodes of clinical mastitis. During the year of study, the incidence rate of clinical mastitis varied from 15.6 to 63.7% of cows among the 9 herds. Mean costs per cow per year in herd for mastitis prevention were: $10 for paper towels, $3 for nonlactating cow treatment, and $10 for teat disinfectants. Mean cost associated with clinical mastitis was $107/episode. Approximately 84% ($90) of the costs attributed to a clinical episode were associated with decreased milk production and nonsalable milk. Costs of medication and professional veterinary fees per clinical episode varied significantly among the 9 herds. Three of the herds did not have a veterinarian treat a clinical episode of mastitis during the year of study even though 2 of these herds had the first and third highest incidence rates of clinical mastitis. When calculated on a per cow in herd basis, mean costs of $40/cow/year were attributed to clinical mastitis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Progress in controlling mastitis in England and Wales

Mastitis in England and Wales has been controlled over the past 20 years while the average size of dairy herds has doubled to 65 cows. The incidence of clinical mastitis has been reduced from approximately 120 to 150 cases per 100 cows to less than 50 cases. The limited data on the prevalence of subclinical mastitis indicate that it has been reduced from over 50 per cent of cows infected to less than half this level. The application of the major mastitis control measures on the farm has doubled over the period 1973 to 1983 and had reached 66 to 90 per cent for individual measures by 1983. The national mean cell count in milk has been reduced from 573,000 to 352,000 cells/ml between 1971 and 1986, and the proportion of herds having annual mean cell counts below 300,000 cells/ml has increased from 15.7 per cent to 40.7 per cent in the last eight years.     

The changes of antioxidative enzyme activities in equine erythrocytes following exercise

The change in activities of 3 major antioxidative enzymes in equine erythrocytes, superoxide dismutase (SOD), glutathione peroxidase (GSHpx), and catalase, was investigated in order to evaluate the effect of exercise. Blood samples were obtained from 11 thoroughbred horses before and immediately after vigorous exercise which induced the increase of plasma lipid peroxide (Lpx) concentration from 1.16 +/- 0.40 nmol/ml to 1.29 +/- 0.34 nmol/ml. Following the exercise, the GSHpx activity in erythrocytes was significantly reduced from 69 +/- 10 IU/gHb to 65 +/- 8 IU/gHb, whereas SOD and catalase activities were not changed. Effects of an antioxidative compound, containing selenium and vitamin E(Se-E), on the response of antioxidative enzyme activities following the exercise were examined. Seven horses were injected intramuscularly with Se-E(Se:25 mg, vitamin E:54.8 mg) and received the same vigorous exercise. After Se-E treatment, plasma Lpx levels before the exercise were decreased from 1.24 +/- 0.09 nmol/ml to 0.86 +/- 0.03 nmol/ml, however, SOD, GSHpx, and catalase activities were not varied. The Se-E treatment slightly prevented the decrease in GSHpx activity and the increase in plasma Lpx level after the exercise, having no effect on SOD and catalase activities. These results suggested that the changes of GSHpx activity in erythrocytes might reflect the protective condition against exercise-induced lipid peroxidation.     

Enhancement of ovine lymphocyte responses: a comparison of selenium and vitamin E supplementation

Lymphocytes of lambs on a low selenium/vitamin E diet were isolated from peripheral blood, and mitogenic responses to phytohaemagglutinin (PHA) tested in the presence of different doses of sodium selenite and emulsified vitamin E added in vitro. An enhancing effect of selenium was observed at doses of 1 ng/ml or less, and reached a plateau at about 10 ng/ml. Toxic effects were evident beyond 1 micrograms/ml. The stimulatory potential of selenium among lambs was inversely related to their ability to respond to PHA in control cultures but was not related to the blood glutathione peroxidase activity of the animals concerned. Optimal doses of vitamin E added to culture (0.15-1.5 micrograms/ml) elevated responses beyond those seen with selenium, but synergistic effects were not apparent. Similar results were obtained when lymphocytes from deficient, myopathic lambs were cultured with serum from lambs supplemented in vivo, and when PHA responses of untreated and treated lambs were compared. Tests with other phytolectins (concanavalin A and pokeweed mitogen) suggested that the two micronutrients exert a differential influence on lymphocyte sub-populations. It was also concluded that the poor lymphocyte responses seen in myopathic lambs can be readily and rapidly reversed by injection of these nutrients, and that prophylaxis is most effective during the first 6 weeks of life.     

Cow milk yield and composition before development of Escherichia coli mastitis

High milk yield, low milk fat and low milk protein were considered as possible predisposing factors to bovine Escherichia coli mastitis. Morning and afternoon milk yields were recorded in 46 Friesian cows later developing E coli mastitis and compared with 92 uninfected controls. Animals developing E coli mastitis gave a significantly higher milk yield than controls. The overall morning: afternoon ratio was (mean +/- se) 1.66 +/- 0.41, with no difference in ratio for the two groups. Further studies on 85 animals later developing E coli mastitis, and 192 controls, in four Friesian herds did not reveal differences in milk fat content (except as related to yield), milk protein or in the interrelationship of days of lactation, milk protein or in the interrelationship of days of lactation, milk fat and milk protein in the two groups. Again there was a correlation between high milk yield and a tendency to develop E coli mastitis but this may have been an age effect in both investigations. No correlation between milk yield and mastitis severity was detected. High yielders which succumbed to E coli mastitis in three herds were producing less milk than mastitis-free controls in the fourth herd which suggests that the correlation is not with yield per se.     

Aetiology of clinical mastitis in six Somerset dairy herds.

Clinical mastitis was monitored in six Somerset dairy herds for one year. The herds all had three-month geometric mean bulk milk somatic cell counts of less than 250,000 cells/ml. Escherichia coli was the predominant pathogen isolated on all the farms and in all months of the year. Environmental pathogens accounted for 61.4 per cent of all cases of clinical mastitis and for 79.3 per cent of the mastitis cases in which an aetiological agent was identified. The mean annual incidence was 41.6 cases per 100 cows (range 14 to 75). Affected cows suffered a mean of 1.5 cases and 16.4 per cent of quarters suffered at least one repeat case. Mastitis due to E. coli was more severe than mastitis due to other causes and it tended to be more severe in early lactation and during the housing period. Mastitis was significantly more severe (grades 2 and 3) in the herd with the lowest bulk milk somatic cell count and in the herd which was kept indoors throughout the year than in the other four herds. Mastitis was fatal in 2.2 per cent of cases and resulted in the death of 0.6 per cent of the lactating cows.     

Vitamins a, e and selenium blood levels in the fat cow syndrome

Blood plasma analyses for vitamins A, E and selenium were performed from calving to five weeks of lactation in 29 cows. Twelve of the 29 cows had fat cow syndrome. The healthy cows had significantly higher (P<0.01) plasma vitamin A (40 μg/dL) and vitamin E (5 μg/mL) levels than the cows with fat cow syndrome (29 μg vitamin A/dL and 3 μg vitamin E/mL). At parturition, vitamin A level in plasma was low (25 μg/dL) but increased progressively thereafter (up to 51 μg/dL) in healthy cows, whereas cows with fat cow syndrome had lower levels of vitamin A, bordering on deficiency. The possible role of vitamin E in the alleviation of fat cow syndrome by affecting oxidation-reduction reactions in the liver is discussed. Significant (P<0.01) difference was not observed in selenium blood plasma level (35 ng/mL) between the two groups of cows or in another random group of 12 cows clinically affected by fat cow syndrome.     

Effect of selenium and vitamin E on antibody production by dairy cows vaccinated against Escherichia coli.

Sixty clinically healthy Holstein cows were randomly assigned to one of four groups according to their age and parity and vaccinated in late pregnancy (day 190) with a multivalent vaccine against Escherichia coli. The 15 cows in the first group (SeE) were injected intramuscularly with a solution of sodium selenite (0.1 mg Se/kg bodyweight) and vitamin E (alpha-tocopherol acetate, 8 U/kg bodyweight), the cows in the second group (Se) received only selenium and the cows in the third group (E) received only vitamin E at the same doses and by the same route of administration; the cows in the fourth group were used as controls. The vaccination and the injections of selenium and vitamin E were repeated 42 days later. The concentration of selenium in whole blood and of vitamin E in serum was determined by fluorometric methods. Specific antibody titres against E coli were determined in serum samples by ELISA. The results showed that the injection of selenium either alone or in combination with vitamin E significantly improved the production of specific antibodies against E coli, and that the production of specific antibodies was greater after the administration of selenium alone.