Parenteral selenium and vitamin E supplementation of weaned beef calves

BACKGROUND: The weaning process in beef calves elicits physiological stress responses that can negatively affect performance and health. Supplementation of vitamins and minerals, particularly selenium (Se) and vitamin E, might be warranted. HYPOTHESIS: That parenteral administration of Se or vitamin E would correct or prevent deficiencies of these nutrients in postweaned beef calves during a backgrounding period (42 days after weaning). ANIMALS: One hundred and forty-four weaned steers (200-250 kg) in 3 trials. METHODS: One trial was conducted with cattle on a dry lot fed a total mixed ration and 2 trials were conducted on cattle on pasture. Selenium was administered at 0.05 mg/kg BW (SC) and vitamin E was administered at 1500 IU on days 0 and 28 (SC). RESULTS: A treatment effect attributable to Se or vitamin E supplementation on average daily gain was not detected in any trials. Parenteral supplementation with Se on days 0 and 28 resulted in higher serum Se concentrations as compared with controls on day 42. Parenteral supplementation with Se on days 0 and 28 improved Se status from marginal to adequate in 1 trial. Parenteral supplementation with vitamin E did not improve serum vitamin E concentrations in any experiment. CONCLUSIONS AND CLINICAL IMPORTANCE: Supplementation with vitamin E or Se or a combination of both did not have a significant effect on calf performance during the 42-day backgrounding period.     

硒对牛生产性能影响的研究进展

硒(Se)是动物必需的微量元素。缺硒会引起一系列疾病,硒过量则会导致硒中毒,而适量补硒则具有多方面的有益影响。硒在牛生产中的作用重大。日粮补硒不仅可以提高血液、牛奶及牛肉的硒含量,还能改善牛的繁殖性能、增强机体免疫力,同时改善牛肉品质。日粮补硒的效果受牛的生理状况、补硒前的硒状况、补饲硒的形态及补饲量的影响。目前,补硒对动物的生理影响研究较为深入,但硒在动物体内的吸收及具体代谢途径有待于进一步研究,这将有助于从机理层面解释硒对动物生理产生的影响。文章系统地综述硒元素的功能以及补硒对牛的影响。     

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.     

Subacute ruminal acidosis (SARA) in grazing Irish dairy cows

Subacute ruminal acidosis (SARA) is a significant production disease of dairy cattle. Previous concerns have been raised over the occurrence of SARA in pasture-fed dairy cattle and the potential consequences of laminitis and lameness. Highly digestible perennial rye grass contains high concentrations of rapidly fermentable carbohydrate and low concentrations of physical effective fibre that may result in SARA. This study conducted a point prevalence survey of rumen health status in grazing Irish dairy cattle fed predominantly perennial rye grass-based pasture. The survey assessed rumen fluid, animal health status, milk production data and pasture composition. A total of 144 cows between 80 and 150 days in milk were sampled on 12 farms. Eleven percent of cows were classified as affected with SARA (pH < or = 5.5), 42% were marginal (pH 5.6-5.8) and 47% were normal (pH>5.8). The study showed that low rumen pH is prevalent in grazing Irish dairy cattle consuming perennial rye grass-based pasture and raises concerns regarding effective pasture utilisation and possible consequences for animal health.     

The effect of long-acting injectable selenium formulations on blood and liver selenium concentrations and liveweights of red deer (Cervus elaphus)

AIM: To evaluate the efficacy of a new long acting injectable selenium ( Se ) formulation to increase the Se status and prevent Se deficiency in red deer. METHODS: Groups of weaned red deer (four stags and six hinds/group) grazing pastures containing <30 mg Se/kg DM were injected subcutaneously with either 0.5, 1.0 or 2.0 mg Se/kg as a new formulation of BaSeO4 (Deposel Multidose), 1.0mgSe/kg of a current formulation (Deposel), or not treated. Blood Se concentrations and liveweight were measured nine times at intervals over 377 and 270 days, respectively. RESULTS: Both formulations of Se elevated blood Se concentrations from 105 nmol/l pre-injection for at least 377 days with peak levels of 1894, 1395 and 818 nmol/l for high, medium and low doses of Deposel Multidose, respectively, at 73141 days, and 1508 nmol/l at 73-141 days for the medium dose of Deposel, which persisted at similar levels for the duration of the study. Deposel Multidose produced fewer and less severe subcutaneous tissue reactions than Deposel. Pastures contained 10 to 30 mg Se/kg DM. There was no significant difference in growth rate between treated and control deer. There was a significant (p<0. 01) linear relationship (y = 1.25x + 71.6, R2=0.86) between blood (x) and liver (y) Se concentrations in the range of 120 - 2100 nmol/l for blood concentrations, and 200 - 3000 nmol/kg for liver concentrations. CONCLUSION: Injections of BaSeO4 in both formulations studied were effective in increasing the Se status of deer but the new formulation produced fewer and less-severe tissue reactions. Young growing red deer appear less sensitive to Se deficiency as measured by weight gain, than sheep and cattle, suggesting that reference ranges for those species are not appropriate for deer. There was a linear correlation between blood and liver selenium concentrations.     

Safety and efficacy of two sustained-release intrareticular selenium supplements and the associated placental and colostral transfer of selenium in beef cattle

One hundred fifty Se-deficient, pregnant, crossbred beef cows were assigned to 1 of 4 treatment groups: group A, Se-deficient control; group B, 1 Se bolus at 0 and 119 days; group C, 1 Se bolus at 0 days; and group D, 2 Se pellets at 0 days. The Se bolus is an osmotic pump designed to release 3 mg of Se/d into the reticulorumen. The Se pellets weight approximately 30 g and contain 10% elemental Se, which is liberated in the reticulorumen. The Se bolus is designed to provide Se supplementation for 120 days and the Se pellets provide supplementation for up to 18 months. Cattle were maintained on Se-deficient pasture or forages prepared from these pastures for the duration of the experiment. Blood samples were collected from cows prior to treatment (time 0) and at 28, 52, 119, and 220 days thereafter and analyzed for blood Se (BSe) concentration. Body weights were recorded at each sampling time. Blood Se concentration of cows from all supplemented groups were significantly (P less than 0.01) higher than control values at all sample dates after treatments began. By the end of the 220-day study, treatment group-B cattle had significantly (P less than 0.01) higher BSe concentrations than any other group. Body weights of treatment groups fluctuated throughout the study, but did not differ (P greater than 0.05) between groups. One cow and 6 calves born to cows during the experimental period died. Necropsy of 5 calves provided no evidence linking these deaths to treatments.(ABSTRACT TRUNCATED AT 250 WORDS)     

全株玉米青贮饲养肉牛最佳日粮组合模式研究

对肉牛常用饲料进行营养价值评定,并选择36头6～24月龄西杂肉牛分4组分别采食不同组合日粮,试验期63～68 d.结果表明,不同饲料之间蛋白含量、有效降解率和有效能含量存在较大的差异.肉牛代谢体重干物质采食量与日粮粗蛋白含量之间存在极显著正相关关系,日增重随代谢体重采食量的增加呈直线增加,经济效益随肉牛日增重的增加而增加.以青贮 秸秆 0.5 kg肉牛浓缩料、青贮 秸秆 2 kg肉牛精料补充料、青贮 牧草 0.5 kg肉牛浓缩料、青贮 牧草 2 kg肉牛精料补充料日粮组合分别饲养西杂肉牛,日增重(ADG)分别为0.66 kg、0.90 kg、0.92 kg、1.08 kg;体况评分(BCS)分别增加0.33分、0.42分、0.56分、0.69分;日盈利分别为3.44元、4.22元、4.70元、4.41元.说明,以全株玉米青贮 优质牧草粗饲料组合饲养肉牛,再补饲含高蛋白和能促进肉牛生长及提高纤维饲料消化率的瘤胃微生物所必须矿物质的肉牛浓缩料或肉牛精料补充料,可使肉牛达到较好的增重,并获得较高的收益.     

Long-acting selenium treatments for sheep

An intraruminal selenium (Se) pellet and a subcutaneous depot of barium selenate, equivalent to 1.6 mg Se/kg body weight, were each effective in maintaining increased blood Se concentrations for at least 200 weeks in ewes at pasture. These treatments given to the ewes 23 to 26 weeks before lambing increased the Se status of their lambs for 4 to 6 months.     

Effect of subcutaneous selenium injection and supplementary selenium source on blood selenium and glutathione peroxidase in feedlot heifers

This study measured the effect on glutathione peroxidase (GSH-Px) and selenium (Se) in whole blood and plasma associated with subcutaneous Se injections in beef heifers fed organic or inorganic Se. Heifers (n = 120) were randomly divided into 2 groups, 1 of which received subcutaneous Se injections. Both groups were given the same total mixed ration with 3 mg of organic or inorganic Se daily. Until week 2, heifers that had received Se injections showed higher concentrations of plasma Se and GSH-Px and whole blood Se (P < 0.001) than those having had no injections. Concentrations of plasma Se and GSH-Px were higher in the group receiving organic Se than the group receiving inorganic Se. Whole blood GSH-Px concentrations increased significantly (P < 0.001) throughout a 12-week period but were not affected by Se source. Combination of Se injections and supplementation could help maintain normal Se and GSH-Px blood status in beef heifers during the first few weeks in the feedlot.     

Analysis of the bone morphogenetic protein 6 gene promoter region in young beef cattle affected by enzootic bovine leukosis

Enzootic bovine leukosis (EBL) is typically observed in cattle over 3 years old. However, some cases of EBL onset in young beef cattle have been reported in Japan. The mechanism for early EBL onset is unclear. In Japan, beef cattle are given large amounts of concentrated feed with low vitamin A. Bone morphogenetic proteins (BMPs) are regulators of cell proliferation, differentiation, and apoptosis, and thought to represent one of the key players in tumor malignancy. The purpose of this study was to evaluate the differences in BMP-6 methylation status between EBL beef cattle under 3 years old and other cattle. We investigated the methylation status of the BMP-6 promoter region in 32 EBL beef cattle under 3 years old. We also compared the methylation status of EBL dairy cattle to that of healthy cattle. Median methylation rate of the BMP-6 promoter region in EBL beef cattle under 3 years old was 8.9%, which was significantly higher than that of other groups. Hypermethylation of the BMP-6 promoter region might contribute to early onset of EBL in beef cattle under 3 years old, and animal feeding management practices specific to beef cattle may affect the methylation status of the BMP-6 promoter region.     

Mineral status of beef cattle in Papua New Guinea

Groups of 22 steers grazed eight diverse environments in Papua New Guinea for one year. Haemoglobin, packed cell volume, MCHC, plasma albumen, calcium, magnesium, phosphorus, zinc, copper and saliva sodium and potassium were measured; half of each group received cobalt supplements. Growth rate was measured. Cobalt deficiency was tentatively diagnosed at two sites, sodium deficiency at five sites and phosphorus at three with two other sites marginal. Sodium supplementation at the three most affected sites corrected sodium status and increased growth rate. Additionally, at two of these sites plasma phosphorus concentration increased to more normal levels presumably due to increased appetite. Statistically significant differences between sites occurred in the concentrations of other minerals but were not related to growth rates. The significance of these results is discussed in relation to assessment of mineral status in beef cattle.     

Plant contents of magnesium, calcium and potassium in relation to ruminant nutrition

Grass tetany and wheat pasture poisoning are metabolic diseases of mature, lactating beef cattle. In some other countries, similar problems occur with dairy cattle. In grass tetany, the animals generally are grazing cool-season forages in which Mg concentration or bioavailability of plant Mg is low. Levels of Mg in the blood serum also generally are low. Grass tetany can occur in beef cattle fed hay made from grass, small grains or alfalfa Medicago sativa L.). In wheat pasture poisoning where animals are grazing small grains forages, blood levels of Ca often are low, and blood Mg also may be low. Both grass tetany and wheat pasture poisoning occur when plants are growing rapidly in the spring, at the time of heavy lactation demand by ruminants for Mg and Ca. When the temperature increases and plants start to grow rapidly in the spring, concentrations of K, N, organic acids, and the ratio of K/(Ca + Mg) all increase, and the percent dry matter decreases. Much research remains to be done to understand all the soil, plant, and animal aspects of grass tetany and wheat pasture poisoning.     

Apparent thiamin status of cattle and its relationship to polioencephalomalacia.

The thiamin status (thiamin concentration in whole blood, plasma, and erythrocytes; erythrocyte transketolase activity) of normal cattle consuming varying diets did not differ from that of cattle with polioencephalomalacia or lead poisoning. Dairy cattle had higher ruminal content of thiamin and lower thiamin destroying activity than did beef cattle. Renal oxalosis was no more frequent in cattle which had polioencephalomalacia than in postnatal calves. In normal beef cattle, approximately 75% of total blood thiamin is in erythrocytes and the remainder in plasma.     

Selenium deficiency of beef cattle in Idaho and Washington and a practical means of prevention

The majority of beef cattle assayed for whole blood glutathione peroxidase (GSH-Px) activity in Idaho and Washington were deficient in selenium. Cattle in the more arid sections of these states tended to have higher selenium levels than those in areas with moderate and high rainfall. Animals pastured on irrigated forages had lower selenium concentrations than those grazed on dry land pasture. Cattle were supplemented by the addition of sodium selenite to a salt-mineral mixture. Ninety mg selenium per kg (ppm) salt-mineral mix fed to cattle significantly (P less than 0.001) elevated selenium (GSH-Px) levels well into normal ranges by 3 months when fed to extremely selenium deficient animals. Thirty ppm selenium was insufficient to raise GSH-Px levels into normal ranges. In addition, 20 ppm selenium was insufficient to sustain blood selenium concentrations of selenium adequate animals. Selenium given in the salt-mineral mix provided an effective, economical, and easily regulated source of dietary selenium. This supplement can be provided the entire year even under range conditions. Calves of cows placed on the 90 ppm selenium supplement had significantly (P less than 0.005) improved weaning weights (10 months) and an indication of a decreased incidence of infectious diseases.     

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.     

Basis for regulation of selenium supplements in animal diets.

Selenium was discovered 174 yr ago but, until 1957, was given little notice by biologists or was vilified as an agent that caused toxicity in grazing ruminants and horses in the northern Great Plains. After its status as an essential nutrient was established, Se received intense scrutiny, and hundreds of papers have been published dealing with its metabolic functions and the consequences of a Se deficiency. Because regions of Se deficiency are so extensive in the United States, great efforts have been made to gain Food and Drug Administration (FDA) approval for Se supplementation of animal diets. Initially, these efforts were thwarted by concern that Se might be carcinogenic. After this concern was resolved, researchers established supplemental Se levels that were efficacious, safe for animals, safe for humans that eat animal products, and protective of the environment. First approval of Se supplements was given in 1974 for supplementation of swine or growing chicken diets at .1 ppm. Supplements for turkey diets were approved at .2 ppm. Ultimately, in 1987, levels of supplemental Se in diets for chickens, turkeys, ducks, swine, sheep, and cattle were approved at .3 ppm. However, FDA regulations do not mention horses or zoo animals, and those who would ensure the welfare of these species by supplementing Se-deficient diets may be in violation of FDA interpretation of the law. In addition, the association of Se with death and deformities in aquatic birds at the Kesterson Reservoir in California has led to pressure on the FDA to reverse the 1987 amendments to the feed additive regulation.(ABSTRACT TRUNCATED AT 250 WORDS)     

An evaluation of a controlled release system for selenium in lambs

The efficacy of 100-day controlled release anthelmintic capsules containing Se for increasing and maintaining the Se status of lambs was evaluated. Capsules containing either 7.7 or 13.9 mg of Se increased the mean blood Se concentrations from 1.50 +/- 8.4 nmol/l in the unsupplemented lambs to 440 +/- 29.8 and 990 +/- 83.4 nmol/l respectively 100 days after their administration. Blood Se concentrations then declined to 250 +/- 21.5 and 380 +/- 50.1 nmol/l respectively by day 210. The addition of 13.9 mg of Se to a 100-day controlled release anthelmintic capsule is an effective method of protecting lambs from Se deficiency for at least 180 days.     

Carcass quality and meat tenderness of Hawaii pasture-finished cattle and Hawaii-originated, mainland feedlot-finished cattle

The objective of this study was to compare the carcass quality and meat tenderness of Hawaii cattle finished on subtropical pasture with those of mainland US feedlot-finished cattle that were shipped from Hawaii after weaning. Rib-eye steak samples were collected from 30 feedlot-finished cattle harvested at a slaughter house in Washington State, USA and from 13 subtropical pasture-finished cattle harvested at a local slaughter house in Hawaii, then shipped to meat science laboratory at the University of Hawaii, Manoa. Samples were aged for 2?weeks at 4°C and frozen for later proximate analysis and meat tenderness measurement. Feedlot-finished cattle had significantly heavier carcass weight (353 vs 290?kg) and thicker backfat (13.5 vs 6.6?mm), but no significant difference was observed in rib-eye area between the two groups. Marbling score (Small) and United States Department of Agriculture quality grade (Choice) of the pasture-finished beef were not significantly (P?相似文献   

Three treatments with ivermectin in year-long control of gastrointestinal nematode parasites of weaner-yearling beef cattle

Four groups of 17 crossbred beef weaners were used in an experiment which extended from 14 November 1985 to 8 October 1986 (328 days). All groups began grazing on separate, contaminated pastures at a stocking rate of 5.3 cattle ha-1 and the different treatments were: Group 1, ivermectin (IVM) injectable X 1 (200 micrograms kg-1) on 14 November only, with provision for individual salvage treatment; Group 2, IVM X 3 on 14 November, 4 February and 2 July; Group 3, IVM X 2 on 14 November and 2 July; Group 4, fenbendazole (FBZ) paste X 2 (5 mg kg-1) on 14 November and 2 July. Pairs of parasite-free tracer calves were grazed on all group pastures for 1 month at the beginning of the experiment (13 November-12 December and in spring (1 April-1 May). Yearling cattle from each group were randomly selected and removed from pasture during spring (n = 2 per group, 3 April) and at the end of the experiment (n = 3 per group, 8 October) for slaughter analysis of worm population characteristics and observation of gross pathology in the abomasum and intestinal tract. At monthly intervals, all cattle were weighed and fecal egg counts, pasture larval counts and plasma pepsinogen values were determined. The results of this investigation demonstrated that three IVM treatments of weaner-yearling beef cattle during year-long grazing, were more effective than a single IVM treatment or two treatments with IVM or FBZ in the enhancement of productivity and protection from the effects of infection with nematode parasites.     

Control strategies for ostertagiasis

There are currently four major options for control of ostertagiasis and other ruminant gastrointestinal parasites. These are the traditional, suppressive, integrated and strategic approaches. Strategic dosing is the most realistic and beneficial approach for most regions of the world, including the U.S.A. It is effective, practical, labor-saving and can yield big economic returns. Today this approach is even more appropriate because of important advances in the technology of controlled release and pulse-release devices. Top priority in worm control programs should be given to dairy replacement heifers in their first year at pasture and to beef calves in the immediate post-weaning period. This is preferable to recommendations for blanket treatment of all beef and dairy cattle, regardless of age, immune status or pasture infectivity. An anthelmintic overkill is both wasteful and potentially harmful in that it increases the selection pressure for drug resistance. It is suggested that better dissemination of information is needed to make producers aware of the benefits of strategic dosing programs. This would eliminate much of the confusion about parasite control and focus attention on simple and effective programs that could significantly reduce current losses to the livestock industries.