首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 515 毫秒
1.
Abstract

Two selenium (Se) supplementation trials were conducted in successive years involving a total of 70 red deer calves 3–15 months of age grazing pasture containing 30–57 ppb of Se on a dry matter basis. The trials compared growth rate, whole blood Se and glutathione peroxidase (GSHpx) concentrations of calves which received periodic doses of oral Se or a single injection of barium selenate (equivalent to 50 mg Se) or no Se supplementation. There were no significant weight gain differences between treated and untreated groups in either trial. Whole blood GSHpx levels were strongly correlated with blood Se levels (r = 0.9278) and produced the following regression equation: GSHpx 0.0155 Se ? 2.292.

In both years the 3 month old calves had GSHpx levels of 6–9 kU/l which probably derived from maternal transfer of Se. The GSHpx levels in unsupplemented calves declined from these levels to a minimum in winter (group means ? 2.6) and then progressively rose the following spring and summer.

Periodical oral dosing with Se or a single injection of barium selenate significantly elevated blood Se and GSHpx levels throughout the trials.  相似文献   

2.
AIM: To examine the effect of intramuscular barium selenate on the blood selenium concentration of horses with marginal selenium status. METHODS: Eighteen mares were assigned to one of six groups. The mares in groups 1-4 received barium selenate at 0.5, 0.75, 1.0 and 1.5 mg Se/kg, respectively, injected into the right pectoral muscle mass. The mares in group 5 received sodium selenate at 0.05 mg Se/kg orally at 8-week intervals. The mares in group 6 were left untreated. Blood samples were collected at 0, 1, 2, 5, 10, 30, 60, 90, 120, 180, 240, 300 and 360 days after the initial treatment for assay of whole blood and plasma selenium. Injection site reactions were recorded on each sampling date. RESULTS: Treatment with barium selenate at each dose rate significantly increased whole blood, plasma and blood cell selenium concentrations when compared to no treatment or oral treatment with sodium selenate, and maintained group mean whole blood selenium concentrations in the adequate range (>1600 nmol/l) until the end of the experimental period of 1 year. The severity of injection site reactions increased with dose rate but was considered acceptable alt the lower dose rates used. CONCLUSION: The injection of barium selenate placed aseptically at a deep intramuscular site was efficacious in correcting the selenium status of mares grazing pasture with a selenium content of 0.01-0.07 mg/kg DM. However, some swelling and fibrosis at the injection site was apparent at all dose rates used. CLINICAL RELEVANCE: There is currently no long-acting selenium supplementation product licensed in New Zealand for use in horses. Barium selenate promises to provide a useful method for selenium supplementation for horses, with an effective duration of at least 1 year following a single injection.  相似文献   

3.
In southern Australia, cattle at risk from selenium (Se) deficiency can be given an oral dose of supplements that are effective in maintaining adequate Se status for between 9 and 12 months. The present study was undertaken to assess the duration of the effect of parenteral barium selenate (BaSe) in raising the Se status of cattle at pasture in an area of marginal Se deficiency. The BaSe was given subcutaneously to Hereford heifers, using an 18-gauge needle. Cattle had regular blood sampling to assay Se, from 8 days before dosing to 1155 days afterwards. Results show that a single injection of BaSe was effective in elevating blood and plasma Se concentrations to normal values for at least 2 to 3 years, when given to beef cattle of low normal Se status. We suggest that a prophylactic dosage of 0.5 mg Se/kg body weight as BaSe should be given every 2 years to prevent Se inadequacy in beef cattle grazing pasture of marginal Se content.  相似文献   

4.
Effects of a single IM injection of selenium-vitamin E (Se-E; 5 mg of Se + 68 IU of alpha-tocopherol/60 kg of body weight) as a pretreatment 14 days before an oral dose of aflatoxin B1 (1.0 mg/kg) were studied in 24 dairy calves. Treatment groups were designated as follows: group 1 = no Se-E or aflatoxin B1 (control); group 2 = Se-E supplementation only; group 3 = aflatoxin B1 dose only; and group 4 = Se-E supplementation before aflatoxin B1 dose. Clinical signs of toxicosis in aflatoxin B1-treated calves included anorexia, ataxia, rough haircoats, increased respiration rates, dyspnea, dehydration, and nasal discharge. Packed-cell volume, RBC, WBC, and hemoglobin were increased in aflatoxin-treated calves. Significant increases in serum aspartate aminotransferase (P less than 0.05) and gamma-glutamyl-transferase (P less than 0.001) activities and prothrombin times (P less than 0.001) were observed in aflatoxin-treated calves, indicating that there was hepatic involvement. Although aflatoxin exposure caused a significant decrease in body weight (P less than 0.01) and feed intake (P less than 0.001) in treatment groups 3 and 4, Se was demonstrated to interact significantly (P less than 0.001) with aflatoxin B1 for feed intake, causing an improved feed intake in treatment group 4 calves.  相似文献   

5.
The objective of this study was to evaluate the effect of selenium (Se) supplementation on milk somatic cell count (SCC) in dairy cows. Twelve multiparous Holstein-Friesian cows were fed a diet containing a suboptimal Se concentration (<0.05 ppm, dry basis) starting 2 months before calving. Supplemented cows (n=6) received a single s.c. injection of barium selenate (1 ml/50 kg BW) 45 days prior to calving, whereas control group was kept unsupplemented. Twenty weeks after calving, two mammary quarters (right side) of each cow were challenged with 205,000 cfu/ml of Staphylococcus aureus (strain Newbould 305). Blood was collected bi-weekly until day 150 of lactation for the analysis of blood glutathione peroxidase (GPx1; EC 1.11.1.9) activity. To re-isolate the challenging pathogen and to evaluate SCC, aseptic milk samples were collected daily starting on the day of challenge, and finishing 7 days after inoculation. Unsupplemented cows had a lower activity of GPx1 through the experiment (P<0.001). Natural log SCC (lnSCC) was higher in unsupplemented than Se-supplemented cows (P=0.04), showing evidence of significance after 5 days. Selenium supplementation of dairy cows fed a diet containing a suboptimal Se concentration, resulted in higher blood activity of GPx1, and lower mean lnSCC after an intramammary challenge with Staph. aureus.  相似文献   

6.
Pregnant sows were injected subcutaneously (s.c.) or intramuscularly (i.m.) with a barium selenate suspension (0.5–1.0 mg Se/kg body weight (b.w.)) and together with control animals fed a commercial diet. No response to the injection was seen either in blood selenium levels or in glutathione peroxidase (GSH-Px) activity in the sows. There was, however, a significant difference in these parameters between piglets born from treated dams and control animals. This status was maintained during the nursing period. In another experiment pigs (20 kg b.w.) on a Se-deficient diet were injected s.c. and i.m. with barium selenate (2.5 mg Se/kg b.w.). The treated groups maintained their blood levels of selenium and GSH-Px activity, although the selenium values in the group treated intramuscularly started to decline after 4 weeks. Organ samples from both groups were equal with regard to selenium at the time of slaughter while the control group showed a rapid decline both in blood selenium levels and GHS-Px activity.  相似文献   

7.
AIM: To determine the relationships between blood selenium (Se) concentrations or glutathione peroxidase activity (GSH-Px), and milk Se concentrations in dairy cows. METHODS: Seventy-two Friesian dairy cows were either untreated or injected with 0.5, 1.0 or 2.0 mg Se/kg liveweight as barium selenate (BaSeO4) formulations, resulting in 6 groups of animals with mean blood Se concentrations that varied from 212 to 2272 nmol/l. Milk samples were collected on Days 104 and 188, and blood samples were collected prior to treatment and on Days 41, 76, 104, 188, 244, and 292 after Se injection. RESULTS: Significant quadratic relationships between blood Se and milk Se concentrations, as well as blood GSH-Px activity and milk Se concentrations, were evident at Days 104 and 188. Using combined data, these were represented by the equations: milk Se = 27.3 + 0.073 blood Se -0.00001 (blood Se)2; R2=0.79, p<0.005, and; milk Se = 34.8 + 4.99 GSH-Px -0.068 (GSHPx)2; R2=0.79, p<0.005. CONCLUSIONS: The Se status of dairy cows can be assessed from milk Se concentrations. CLINICAL SIGNIFICANCE: Bulk-tank milk Se concentrations could be evaluated as a method to assess the Se status of dairy herds.  相似文献   

8.
The purpose of the trial was to establish the effect of the injection of the lysozyme dimer or vitamins connected with Se on the activity of chosen antioxidant enzymes and the total antioxidant status in pregnant heifers. Examinations were carried out during winter season in one farm on 21 heifers aged 22-24 months. Between the 21st and 14st day before expected parturition, seven heifers were once i.m. injected with antioxidants (Vitamin A-600 000 i.u.; Vitamin D3-200 000 i.u.; Vitamin E-1.5 mg/kg b.w., Selenium-0.022 mg/kg b.w.), and the next seven animals with lysozyme dimer (Lydium-KLP) at a dose of 0.02 mg/kg b.w. versus 7 non-treated control animals. Blood samples were taken before injection and then in hour 24 and 72 after injection, and between, the 7th and 14th day after calving. The activity of superoxide dismutase (SOD), glutathione peroxidase (GSHpx), glutathione reductase (GSHred) and total antioxidant status (TAS) were measured by colorimetric method with the use of Randox kits. The mean value of SOD activity 21-14 days before expected calving was 704.8 +/- 294.6 U/ml of whole blood, GSHpx 59222 +/- 23699 U/l of whole blood, GSHred 110.8 +/- 22.5 U/l and TAS 0.33 +/- 0.15 mmol/l of serum. These indicators did not change in the control group with the exception of a statistically insignificant decrease in SOD activity after parturition. Statistically significant increase in blood SOD activity was noted only in the first day after injection of vitamins combined with selenium. These antioxidants also caused an insignificant increase in blood GSHpx activity in 72 hour following the injection, and in the second week after calving (statistically significant). The injection of antioxidants or lysozyme dimer did not change the activity of blood GSHred. However, an increase in the TAS was found in hour 24 (non significant) and 72 (statistically significant) following the single injection of lysozyme dimer.  相似文献   

9.
The effect of Se supplementation before or after calving on Se status in deficient cows and their calves was studied using 72 beef cows in two experiments. In Exp. 1, cows calving in February or March 1997 were supplemented orally for 15 d in late pregnancy with 13.0, 32.5, or 45.5 mg of Se/d as sodium selenite. Glutathione peroxidase (GSH-Px) activities were measured in red blood cells (RBC) or plasma of cows and calves at d 15 and between d 17 and 88 after calving. In Exp. 2, cows calving in January 1997 were supplemented orally with .0, 13.0, or 32.5 mg of Se/d for 15 d postpartum, and calves were injected with 1.38 mg of Se when 2 d old and at an average age of 49 d. The GSH-Px activities were measured in 30-d-old calves and in cows and calves between d 77 and 115 after calving. In both experiments, Se supplementation resulted in adequate Se status for the dams. The increase in RBC GSH-Px activity was faster with 45.5 mg of Se/d, and GSH-Px activities remained high for up to 98 d after the end of supplementation. The improvement in Se status in calves as a result of maternal supplementation was greater in Exp. 1 than in Exp. 2, suggesting that the placental transfer of Se is more efficient than milk transfer. Prepartum oral Se supplementation of deficient beef cows with 13.0 mg of Se/d for 15 d allowed adequate Se status of dams and calves, and 45.5 mg of Se/d resulted in a faster improvement of Se status. Parenteral administration of 1.38 mg of Se to newborn calves did not sustain normal Se status in calves issued from deficient cows.  相似文献   

10.
A commercial fertiliser, consisting of a poorly soluble barium selenate core with a coating of highly soluble sodium selenite, was evaluated in 2 trials for the provision of selenium (Se) to grazing sheep. The fertiliser was administered at a level of 1 kg per hectare to 3 of 6 kikuyu paddocks during 1995 and 1996 in Trial 1, while the other paddocks were left untreated. The Se status of SA mutton merino ram lambs, as reflected by whole blood, liver and kidney Se concentrations, was elevated (P < 0.01) for at least 5 months after application of the fertiliser. Whole blood and liver Se concentrations of animals grazing unfertilised control paddocks were indicative of a subclinical Se deficiency at times (<100 ng Se/ml whole blood and <300 microg Se/kg liver dry matter). In Trial 2, 4 of 7 paddocks on which an oat fodder crop was established were treated with the Se fertiliser during 1995 and 1997. The remaining 3 paddocks were left unfertilised as controls. Groups of 10-15 pregnant SA mutton merino ewes were introduced to these paddocks within 2 weeks of parturition. These ewes and their progeny utilised these paddocks for a mean (+/- SD) period of 41 +/- 8 days after parturition. The whole blood Se concentrations of these ewes and their offspring were elevated (P < 0.01) relative to their contemporaries utilising control paddocks. No suggestion of a subclinical Se deficiency was discernible in animals grazing control paddocks, although whole blood Se levels approached 100 ng Se/ml during 1997. The application of Se fertiliser did not result in improvements in ewe reproduction or lamb growth. There was a suggestion of an improvement (P = 0.21) in mean (+/- SE) lamb survival on paddocks receiving Se fertiliser compared to control paddocks (71.5 +/- 4.6% vs 62.2 +/- 5.3% respectively).  相似文献   

11.
OBJECTIVE: To determine whether parenteral administration of selenium (Se) to calves and the amount of forage and protein provided to their dams affects unadjusted body weight, adjusted 205-day body weight, and average daily gain (ADG) of suckling beef calves. DESIGN: Randomized controlled field trial. ANIMALS: 151 Hereford-Angus crossbred beef calves. PROCEDURE: Newborn calves, randomly assigned to 1 of 3 groups, served as untreated controls (n = 49) or were given Se (0.05 mg/kg [0.023 mg/lb] of body weight, SC) once within 2 days of birth (55) or within 2 days of birth and on days 70, 114, and 149 (47). Until day 149, cow-calf pairs were pastured in fields in which the amount of available forage was high or low and supplemental protein was or was not provided. Calves were weighed on days 1, 70, 149, and 209. On days 160 and 209, blood was obtained from 33 calves for measurements of Se concentration. RESULTS: Mean consumption of supplemental protein was 0.65 kg/dam/d. Between days 1 and 70, calves that received the first of 4 multiple injections of Se had significantly greater ADG than control calves. Average daily gain for calves given only 1 injection was not significantly different from controls. Between days 70 and 149, ADG of calves increased with dietary supplementation of protein to their dams. CLINICAL IMPLICATIONS: Strategic administration of Se to calves and dietary supplementation of protein to their dams may result in greater ADG in suckling beef calves during specific time intervals.  相似文献   

12.
Eighty-three weaned beef calves severely deficient (less than 20 micrograms/L) in blood selenium (Se) were allotted by sex, weight and breed to one of six regimens of Se supplementation for 108 days to examine the efficacy of various Se supplementation programs and to monitor the repletion rate of blood Se concentrations. Cattle in treatment 1 received an IM injection of sodium selenite and an ad libitum feeding of 20 mg Se/kg salt-mineral mixture. Salt-mineral mixtures (treatments 2, 3, 4 and 5) were formulated to contain 20, 40, 80 and 160 mg Se/kg supplement, respectively, and were offered free-choice. Treatment 2 served as the selenium-treated control because 20 mg Se/kg supplement was the maximum permissible by FDA in commercial salt-mineral preparations at the time of this study. Cattle in treatment 6 received a salt-mineral supplement which contained no Se but dried brewers grain (434 micrograms Se/kg) was incorporated in the ration as an organic source of Se and fed at a rate of 1.1 kg/head/day. There was a within group time/treatment interaction (P less than 0.01) among all treatments as blood Se concentrations significantly increased over time. Final mean whole blood Se concentrations for treatments 1-6 were 87.8, 60.6, 95.1, 123.1, 154.2 and 91.4 micrograms/L, respectively. Treatments 1, 3, 4, 5 and 6 effectively increased and maintained whole blood Se concentrations at adequate levels (greater than 70 micrograms/L) by day 84. Treatment 2 (control) increased blood Se during the 108-day study, but blood Se concentrations never exceeded marginal levels (50-70 micrograms/L). Cattle consumed less salt-mineral supplement as the concentration of Na selenite increased from 20 to 160 mg Se/kg supplement.  相似文献   

13.
Parenteral selenium and vitamin E supplementation of weaned beef calves   总被引：1，自引：0，他引：1  
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.  相似文献   

14.
The main aim of this trial was to define the possible differences between selenite and selenate in their ability to increase the selenium (Se) concentration of milk, in comparison with organic Se. Dairy cows (n = 42) were fed a basal diet containing .10 to .12 mg Se/kg DM for 5 mo and were then divided into four groups of 10 or 11, as similar as possible in age and stage of lactation. During the next 84 d, the cows in three of the groups were supplemented with 3 mg of Se daily, whereas the cows in one control group remained unsupplemented. The Se supplement was given as sodium selenite, sodium selenate, or a Se yeast product. The total Se concentration of the diets varied with the cows' stage of lactation and was for the supplemented groups .24 to .31 mg/kg DM, but remained between .10 and .12 mg/kg in the control group. At the end of the trial, the mean whole blood Se concentrations in the selenite, selenate, yeast, and control groups were 138, 141, 165, and 104 microg/L, respectively. The Se concentration in plasma apparently reached a plateau level within 4 wk, at approximately 75 microg/L in the selenite group, 80 microg/L in the selenate group, and 90 microg/L in the yeast group. In the control group the mean concentration in plasma remained at approximately 50 microg/L. The increase of the activity of glutathione peroxidase (GSH-Px) in the erythrocytes was significantly higher in the supplemented groups than in the control group. The mean concentrations of Se in milk in the selenite, selenate, and yeast groups were 16.4, 16.4, and 31.2 microg/L, respectively, whereas the concentration remained at approximately 14 microg/L in the control group. The milk Se concentration reached a plateau within 1 wk after the start of Se supplementation. Dietary supplementation with selenite and selenate, thus, had only a limited effect on the Se concentration in milk, and there was no significant difference between the two inorganic compounds in any variable measured. Organic Se was much more effective than inorganic Se in increasing the concentration of Se in milk.  相似文献   

15.
Blood selenium levels were found to fluctuate throughout the year, being highest during the indoor season when the greatest amounts of compound concentrates were fed. From October to January the average blood selenium levels increased from 0.10 μg/ml to 0.18 μg/ml (15 cows). Subcutaneous injections of barium selenate (500 mg selenium) increased the blood selenium levels significantly. The treated group (15 cows) reached average levels of about 0.21 μg/ml blood during the indoor season.The effect of oral supplementation of sodium selenite (for 2 months) on the levels of plasma selenium, blood selenium and glutathione peroxidase activity was investigated. Plasma selenium was found to give an immediate reflection of the daily selenium intake. Maximum activity of glutathione peroxidase was reached 1 month after the end of the supplementation period.It is concluded that if selenium enriched concentrates are used in a normal feeding regimen, further supplementation with selenium does not seem to be necessary.  相似文献   

16.
Three groups of four lactating cows received a subcutaneous injection of 0 . 05, 0 . 10 and 0 . 15 mg Se/kg body weighty respectively administered as sodium selenate. A fourth group was injected with saline. In all the cows injected with sodium selenate, the concentration of Se in blood increased rapidly and was significantly higher than in control cows for two days in the group receiving the lowest dose and for 182 days (the duration of the experiment) in the two other groups. The activity of glutathione peroxidase in blood increased slowly in all cows injected with sodium selenate and was significantly greater than in control cows after 15, 22 and 29 days respectively, and remained significantly greater for 63, 91 and 182 days respectively. In a second experiment a single subcutaneous injection of 0 . 15 mg Se/kg body weight had no effect on the mean milk yield of 37 animals (19 . 1 kg/day) compared with the milk yield of a similar group of control animals (19 . 1 kg/day) during 70 days. The concentration of Se in milk was significantly higher on the first (168 microgram/litre) and second (69 microgram/litre) day after injection than in control animals (mean 26 microgram/litre).  相似文献   

17.
On December 2, 1999, 120 pregnant cows were weighed, their body condition scored, and then sorted into six groups of 20 stratified by BCS, BW, breed, and age. Groups were assigned randomly to six, 5.1-ha dormant common bermudagrass (Cynodon dactylon [L.] Pers.) pastures for 2 yr to determine the effects of supplemental Se and its source on performance and blood measurements. During the winter, each group of cows had ad libitum access to bermudagrass/dallisgrass (Paspalum dilatatum Poir.) hay plus they were allowed limited access (1 to 4 d/wk) to a 2.4-ha winter-annual paddock planted in half the pasture. Treatments were assigned randomly to pastures (two pastures per treatment), and cows had ad libitum access to one of three free-choice minerals: 1) no supplemental Se, 2) 26 mg of supplemental Se from sodium selenite/kg, and 3) 26 mg of supplemental Se from seleno-yeast/kg (designed intake = 113 g/cow daily). Data were analyzed using a mixed model; year was the random effect and treatment was the fixed effect. Selenium supplementation or its source had no effect (P > or = 0.19) on cow BW, BCS, conception rate, postpartum interval, or hay DMI. Birth date, birth weight, BW, total BW gain, mortality, and ADG of calves were not affected (P > 0.20) by Se or its source. Whole blood Se concentrations and glutathione peroxidase (GSH-Px) activity at the beginning of the trial did not differ (P > or = 0.17) between cows receiving no Se and cows supplemented with Se or between Se sources. At the beginning of the calving and breeding seasons, cows supplemented with Se had greater (P < 0.01) whole blood Se concentrations and GSH-Px activities than cows receiving no supplemental Se; cows fed selenoyeast had greater (P < or = 0.05) whole blood Se concentrations than cows fed sodium selenite, but GSH-Px did not differ (P > or = 0.60) between the two sources. At birth and on May 24 (near peak lactation), calves from cows supplemented with Se had greater (P < or = 0.06) whole blood Se concentrations than calves from cows fed no Se. At birth, calves from cows fed seleno-yeast had greater (P < or = 0.05) whole blood Se concentrations and GSH-Px activities than calves from cows fed sodium selenite. Although no differences were noted in cow and calf performance, significant increases were noted in whole blood Se concentrations and GSH-Px activities in calves at birth as a result of feeding of seleno-yeast compared to no Se or sodium selenite.  相似文献   

18.
Food and Drug Administration regulations currently permit addition of .3 mg of Se per kilogram of diet for chickens, turkeys, ducks, swine, sheep, and cattle. However, field reports indicate that this level may not be adequate for ruminants in all situations. Because sodium selenite is the most common supplemental form and is known to be readily absorbed to particles or reduced to insoluble elemental Se or selenides in acid, anaerobic environments, studies were conducted with dairy cattle, sheep, and horses fed sodium selenate to determine whether Se from this source was more bioavailable than Se from sodium selenite. A 2-wk period of no Se supplementation was followed by 49 or 56 d of Se supplementation at .3 mg/kg of dietary DM. Serum Se concentrations and glutathione peroxidase (GSHPx) activities measured initially and periodically thereafter revealed no difference between Se forms in sheep and horses and only a small (P less than .05) advantage for selenate in supporting serum Se concentration in dairy cattle. Selenium concentrations in skeletal muscle and liver of sheep were not different between Se forms. Serum Se, but not GSHPx, increased with time, and .3 mg of supplemental Se per kilogram of dietary DM from either sodium selenate or sodium selenite supported normal serum Se concentrations in sheep, dairy cattle, and horses.  相似文献   

19.
The objectives were to determine if strategic supplementation of range cows with a long-acting (6 mo), trace mineral, reticulorumen bolus containing Cu, Se, and Co would: (1) increase cow BCS and BW, and calf birth, weaning, and postweaning weights, or weight per day of age (WDA); (2) increase liver concentrations of Cu or Zn in cows, or blood Se, Cu, or Zn concentrations in cows and calves; and (3) vary by cow breed for any of these response variables. There were 192 control and 144 bolused Composite cows (C; 25% Hereford, Angus, Gelbevieh, and Senepol or Barzona); 236 control and 158 bolused Hereford (H) cows; and 208 control and 149 bolused Brahman cross (B) cows used in a 3-yr experiment. Cows were weighed and scored for body condition in January, May, and September, and all bolused cows received boluses in January. Each year, from among the 3 breed groups a subset of 15 control and 15 bolused cows (n = 90) had samples obtained in January and May for liver Cu and Zn, blood Se, and serum Cu and Zn. As for cows, blood and serum from the calves of these cows were sampled each year in May and September for Cu, Se, and Zn. There was a significant breed x year x treatment interaction (P = 0.001) for cow weight loss from January to May. Calf WDA, weaning, and postweaning weights did not differ (P > 0.40) between bolused and control cows, but there was a significant (P = 0.022) breed x year x treatment interaction for birth weight. Liver Cu was deficient (< 75 ppm; P < 0.001) in control cows and adequate (< 75 to 90 ppm) for bolused cows. Liver Cu differed by year (P < 0.001). Blood Se was adequate (< 0.1 ppm) for all cows except in January 2001 and 2002. There was no difference (P > 0.50) in blood Se between treatment groups in January, but bolused cows had greater (P < 0.01) blood Se in May. Breed differences for blood Se concentrations existed for bolused cows, with B having greater (P < 0.05) blood Se than either C or H cows. Breed differences also existed for control cows, with H having less blood Se (P < 0.04) than B or C cows. Calves from bolused cows had greater blood Se than calves from control cows (P = 0.01). Supplementation via a long-acting trace mineral bolus was successful in increasing liver Cu in cows and blood Se in cows and calves, but the responses varied by year. Bolus administration had variable effects on BW change in early lactation, depending on breed and year, which may indicate the need for breed- and year-specific supplementation programs.  相似文献   

20.
Long-acting selenium treatments for sheep   总被引：1，自引：0，他引：1  
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.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号