JDS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kincaid, R. L.
Right arrow Articles by Johnson, A. B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kincaid, R. L.
Right arrow Articles by Johnson, A. B.
J. Dairy Sci. 86:1405-1414
© American Dairy Science Association, 2003.

Effect of Dietary Cobalt Supplementation on Cobalt Metabolism and Performance of Dairy Cattle

R. L. Kincaid*,1, L. E. Lefebvre*, J. D. Cronrath*, M. T. Socha{dagger} and A. B. Johnson{dagger}

* Animal Sciences Department, Washington State University, Pullman 99164-6351
{dagger} Zinpro Corp., Eden Prairie, MN 55344-7298

Corresponding author:
R. L. Kincaid; e-mail:
rkincaid{at}wsu.edu.


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS
 REFERENCES
 
Three studies were conducted with dairy cattle fed diets with added Co. The first study examined cow age and added dietary Co on Co in liver and blood. Nonpregnant, nonlactating Holstein cows were blocked by age (2.5 or 6.5 yr) and assigned to either a control diet or a diet supplemented with 9 mg Co per day. The Co concentration of liver, taken on d 60, was not affected by dietary Co but was higher in the younger cows. The cytosolic fraction of liver contained the most Co, and the subcellular distribution of Co was not affected by total Co in liver. In a second study, Holstein cows were assigned to one of three treatments of dietary Co from 21 d prepartum until 120 d postpartum. There was an interaction of time x treatment x parity such that milk yield response to Co supplementation differed between multiparous cows and primiparous cows. Supplemental Co did not increase Co in serum, colostrum, milk, or liver. Primiparous cows secreted colostrum and milk with higher Co concentrations than did multiparous cows. Likewise, serum B12 levels were higher in primiparous than multiparous cows and declined with increasing days in milk (DIM). Serum Co also decreased from 7 to 120 DIM. In a final study, a Co supplement in the starter diet did not affect Co in serum or liver of young calves. In conclusion, supplemental dietary Co did not affect secretion of Co in milk, tissue retention, or subcellular distribution of Co within the liver. Primiparous and multiparous cows differed in their milk yield response to dietary Co supplementation.

Key Words: cobalt • cow • calf • vitamin B12

Abbreviation key: AAS = atomic absorption spectrophotometry, EE = ether extract


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS
 REFERENCES
 
Cobalt is an essential trace element in ruminant diets for the production of vitamin B12 by the rumen microbes to meet the vitamin B12 requirements of both the ruminal bacteria and the host animal (McDowell, 1992). The NRC (2001) lists the dietary requirement of dairy cattle for Co as 0.11 mg/kg; however, ruminal synthesis of B12 increased nearly 20-fold in sheep when dietary Co was increased from 0.1 to 0.5 mg/kg (Mills, 1981). Furthermore, Kawashima et al. (1997) found the concentrations of vitamin B12 in serum and liver of sheep were increased until dietary Co was 40 mg/kg. In addition, Allen (1986) reported increased cellulose digestibility in vitro of diets containing 10 mg/kg added Co.

In the ruminant, the efficiency of production of vitamin B12 (cobalamin) from Co is low, only about 3%; however, efficiency increases to about 13% when Co intake is low (Smith and Marston, 1970). The relative production of cobalamin and the cobalamin analogs, which have no B12 activity, is affected by the diet (Dryden and Hartman, 1971; Sutton and Elliot, 1972). In general, diets that are largely composed of roughages tend to promote greater production of cobalamin, and diets containing larger amounts of concentrates tend to reduce cobalamin production and to lower the ratio of cobalamin to the various analogues of vitamin B12 (Sutton and Elliot, 1972). Elliot et al. (1979) established that vitamin B12 in blood is reduced in cows during early lactation.

Relatively little is known about Co metabolism in cattle. Although some nonvitamin B12 roles for Co may exist, none have been clearly elucidated. Elemental Co is absorbed through the intestinal tract (Wapnir, 1990) and transported in blood to various tissues (Underwood and Suttle, 1999). The liver contains the highest concentration of Co within tissues and is considered the main storage site (Underwood and Suttle, 1999). Thus, the objectives of the current studies were to determine if supplemental dietary Co affected tissue retention of Co, the subcellular distribution of Co within liver, milk production of cows, and growth of young calves.


   MATERIALS AND METHODS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
RESULTS AND DISCUSSION
 CONCLUSIONS
 REFERENCES
 
Three studies were conducted to evaluate Co supplementation effects on Co metabolism in dairy cattle. The protocols were approved by the Institutional Animal Care and Use Committee of Washington State University.

Study 1.
Nonpregnant, nonlactating Holstein cows (n = 8) were blocked by age (2.5 yr, range 2 to 3 and 6.5 yr, range 5 to 7) and then randomly assigned to one of two treatment groups. Cows receiving each treatment were housed together and group fed. Treatments were a pelleted concentrate that was fed to supply either 3.6 (control) or 12.4 mg (supplemented) Co daily. The concentrate consisted of 87.5% ground corn, 9.2% soybean meal (44% CP), 1.24% limestone, 1.16% trace mineral premix, 0.56% animal fat, 0.22% Se premix (200 mg/kg Se), 0.03% vitamin A premix (30,000 IU/g), and 0.05% cellulose gum. The trace mineral premix contained 69.17% iodized salt, 10.91% Zn methionine (10% Zn, Zinpro Corp., Eden Prairie, MN), 5.33% Zn sulfate (36.4% Zn), 7.58% Mn methionine (8% Mn, Zinpro Corp.), 1.7% Mn oxide (72% Mn), 3.79% Cu lysine (10% Cu, Zinpro Corp.), and 1.52% Cu sulfate (25% Cu). In the premix with added Co, 1.89% Co glucoheptonate (2.5% Co) replaced an equal amount of iodized salt. The concentrate was fed once daily at the rate of 3.6 kg/cow per day. In addition, pea hay (0.4 mg/kg cobalt) and water were available free choice at all times. The chemical composition of the concentrate and hay is given in Table 1Go. Cows were fed their treatment diets for 60 d before slaughter.


View this table:
[in this window]
[in a new window]
  		Table 1. Chemical composition of the diet components fed to nonlactating Holstein cows for 60 d (Study 1).1
 
Study 2.
Holstein cows (n = 36; 9 primiparous and 27 multiparous cows), 21 d before their expected calving date, were assigned to prepartum diets of grass hay provided free choice and individually fed 3.3 kg (DM basis) of concentrate per day to provide treatments designated as low, medium, and high intakes of Co. The concentrate was composed of 81.2% ground corn, 11.9% soybean meal (44% CP), 5% molasses, 1% trace mineral premix (Table 2Go), 0.5% iodized salt, 0.1% vitamin D premix (8810 IU/g), 0.025% vitamin A premix (30,000 IU/g), 0.2% Se premix (200 mg/kg Se as Na selenite), and 0.05% cellulose gum. Fed at 3.3 kg/d, the concentrate supplied the dry cows with 0, 12, and 25 mg of Co per day. Based upon chemical analysis of the hay and concentrates (Table 3Go) and an estimated hay intake of 9.1 kg/d, prepartum intakes of Co were 3.1, 13.8, and 23.6 mg/d for the dry cows.


View this table:
[in this window]
[in a new window]
  		Table 2. Trace mineral premixes for dry cow concentrates (Study 2).
 

View this table:
[in this window]
[in a new window]
  		Table 3. Chemical composition of concentrates and hay fed to dry cows (Study 2).1
 
Subsequent to parturition, cows remained assigned to their respective treatments of low, medium, and high Co treatments until 120 DIM. The dietary concentrations of Co for the three treatments were 0.37, 0.68, and 1.26 mg/kg Co. The lactating cows were individually fed a TMR (Table 4Go) via Calan feeding gates, and daily feed intakes were measured. The chemical composition of the TMR is given in Table 5Go. Beginning at 90 DIM, all cows received injections of recombinant bovine somatotropin (Posilac 1 Step, Monsanto Co., St. Louis, MO) on 14-d intervals.


View this table:
[in this window]
[in a new window]
  		Table 4. Composition of total mixed rations for lactating cows (Study 2).
 

View this table:
[in this window]
[in a new window]
  		Table 5. Chemical composition of TMR for lactating cows1,2 (Study 2).
 
Study 3.
Newborn female Holstein calves (n = 18) were assigned to receive either a complete textured starter (0.63 mg/kg Co) or starter with added Co (1.34 mg/kg Co). The ingredient composition of the starter was 30.2% steam-rolled barley, 32.2% ground corn, 15.27% alfalfa pellets, 15.1% soybean meal (44% CP), 4.24% molasses, 0.57% iodized salt, 0.56% animal fat, 0.28% trace mineral premix, 0.11% pellet binder, 0.11 % Se premix (200 mg/kg Se), 0.05% vitamin A premix (30,000 IU/g), 0.03% vitamin D premix (8810 IU/g), and 0.03% vitamin E premix (DL-alpha tocopheryl acetate, 500 IU/g). The trace mineral premixes contained 73.62% iodized salt, 1.3% copper sulfate (25% Cu), 3.24% copper lysine (10% Cu, Zinpro Corp.), 1.41% manganese oxide (72% Mn), 6.47% manganese methionine (8% Mn, Zinpro Corp.), 9.4% zinc methionine (10% Zn, Zinpro Corp.), and 4.56% zinc sulfate (36.4% Zn). In the trace mineral premix used in the Co-supplemented starter, 1.55% cobalt glucoheptonate (2.5% Co, Zinpro Corp.) was substituted for an equal amount of iodized salt. Calves were individually housed in sheltered runs bedded with wood shavings. The chemical compositions of the starters were 17% CP, 20% NDF, 8.5% ADF, 0.87% Ca, 0.32% P, 36 mg/kg Zn, and 7.6 mg/kg Cu. In addition to the starter, calves were fed 2.27 kg of pooled milk twice daily (0500 and 1500 h) during their first 4 wk and 1.14 kg milk twice daily for the subsequent 2 wk. Feed refusals were weighed back and fresh feed added once daily.

Measures of Performance and Sampling
Experiment 1.
Blood samples were collected into heparinized and nonheparinized vacutainers on d 1, 30, and 60. Cows were humanely killed on d 60, and samples were taken from the ventral lobe of the liver within 20 min after exsanguination. Liver samples were individually identified, refrigerated at 4°C until the following day, then homogenized in three volumes of 0.1 M ammonium acetate buffer (pH 7.4). The liver homogenates were separated into subcellular components by differential centrifugation according to Chen et al. (1999).

Experiment 2.
Daily DMI were recorded for lactating cows, and samples of the TMR were taken weekly and composited by month. Cow BW and condition scores were taken on d -21, -7, 7, 30, 60, 90, and 120 relative to parturition. Blood samples were collected into heparinized and nonheparinized vacutainers on d -21, -7, 0, 7, 21, and 120. Immediately postpartum, a sample of colostrum was collected. Milk yields were recorded daily, and samples of a.m./p.m. milk were taken monthly for analysis via an infrared spectrophotometer (Bentley 2000; Bentley Instruments, Chaska, MN; AOAC, 1990) of major components by the regional DHIA laboratory (Burlington, WA). Samples of serum, whole blood, colostrum, and milk were frozen until analysis. Percutaneous liver biopsies were obtained under a local anesthesia (5 mg of Lidocaine and 50 mg of Flunixine meglumine) at 120 DIM between the 9th and 10th intercostal space using a 15-cm Tru-Cut biopsy needle (Tranvenol Labs, Deerfield, IL). Biopsy specimens were transferred to a tared vial and reweighed. The samples were stored at -30°C until analysis.

Experiment 3.
Calves were weighed weekly on the same day each week. Feed samples were collected weekly and composited by month. Blood samples were collected via jugular venipuncture in both heparinized and nonheparinized vacutainers within the first 24 h of birth and again at the end of wk 6 and 12. Hematocrit concentrations were determined on each sample, and a subsample was spun at 1875 g for 20 min to obtain serum. Whole blood and serum samples were then frozen at -20°C to await further analysis. Liver samples were taken by biopsy (as described above) from each calf at 12 wk of age and frozen at -20°C until analysis. Ruminal fluid samples from calves were also taken at 12 wk of age using an esophageal tube, and 4 ml of ruminal fluid was mixed with 1 ml of 25% sodium metaphosphoric acid. Fluid was separated by centrifugation at 25,133 x g for 30 min, and the supernates were kept refrigerated at 4°C until analyzed.

Analyses
Composite feed samples were dried (60°C for 48 h), ground to pass a 2-mm screen (Wiley mill; Arthur H. Thomas Co., Philadelphia, PA), subsampled, then reground to pass through a 1-mm screen, subsampled again, and stored at -20°C until further analysis. Feed analysis consisted of DM at 100°C (AOAC, 1990), CP by an automated nitrogen analyzer (Leco FP-528), ether extract (EE) (AOAC, 1990), and NDF and ADF using an Ankom 200 Fiber Analyzer (Ankom Technologies, Fairfield, NY). Blood, liver, homogenates of liver, colostrum, and milk samples were analyzed for Co by neutron activation analysis (60Co with a half-life of 5.27 yr using a multichannel analyzer) at the Washington State University’s Nuclear Reactor Center. Copper, Ca, Zn, Cu, and Fe concentrations were determined by atomic absorption spectrophotometry (AAS; Robinson, 1975); K and Na by atomic emission spectrophotometry (Robinson, 1975); Mn by graphite furnace AAS (CHGA-400, Perkin-Elmer, Norwalk, CT); Zn in liver samples taken via biopsy by neutron activation analysis; Co in feeds by AAS (University of Missouri-Columbia Experiment Station Chemical Labs); and P by colorimetry (AOAC, 1990). Milk fat and protein composition were done via infrared spectrophotometer (AOAC, 1990) at the regional DHIA laboratory. Glucose analysis was by a commercial kit (Sigma Chemical Co., St. Louis, MO) and NEFA were also done using a commercial kit (NEFA-C, Wako Chemical GmbH, Neuss, Germany). Vitamin B12 analyses were by radioimmunoassay modified so proteins were denatured by heating samples in a boiling water bath for 10 min instead of incubating at 37°C for 30 min (USDA Human Nutrition Laboratory, Grand Forks, ND). Analysis of VFA in rumen fluid was by gas chromatography, using a Hewlett Packard 5890 chromatograph equipped with a C-5000 column (Alltech, Deerfield, IL) with an i.d. of 3.9 mm. Settings included injector at 225, detector at 250, initial temperature of 120°C, initial time of 12 min, ramp rate of 5°/min, final temperature of 140°C, final time of 5 min, and helium flow of 2 ml/min.

Statistical Analysis
Experiment 1.
All data were statistically analyzed using the PROC MIXED procedure in SAS Version 8.0 (SAS, 2001). Data for Co concentrations in liver were found to be nonnormally distributed, so they were log transformed prior to analysis. All other data were normally distributed. The statistical model used in the serum and whole blood analyses was Y = µ + {alpha}i + ßj + {delta}k + ({alpha}{delta})ik + (ß{delta})jk + ({alpha}ß)ij + eijk where {alpha}i = effect of diet, ßj = age effect, {delta}k = day effect, ({alpha}{delta})ik = interaction effect between diet and day, (ß{delta})jk = interaction effect between age and day, ({alpha}ß)ij = interaction effect between diet and age, and eijk = experimental error. The statistical model used for the whole liver analysis was Y = µ + {alpha}i+ ßj + ({alpha}ß)ij + eij where {alpha}i = effect of diet, ßj = age effect, ({alpha}ß)ij = interaction effect of diet and age, and eij = experimental error. For the liver fractions, the statistical model used was Y = µ + {alpha}i + ßj + {delta}k + dl ({alpha}ißj) + ({alpha}{delta})ik + (ß{delta})jk + ({alpha}ß{delta})ijk + eijkl where {alpha}i = effect of diet, ßj = effect of age, {delta}k = liver fraction, dl ({alpha}ißj) = interaction effect of cow by cow within diet age subclass, ({alpha}{delta})ik = interaction effect of diet and liver fraction, (ß{delta})jk = interaction effect of age and liver fraction, ({alpha}ß{delta})ijk = interaction of diet, age, and liver fraction, and eijkl = experimental error. Contrast statements were used to determine differences among fractions. Significance was declared at P <= 0.05.

Experiment 2.
Data were analyzed by general linear model of PROC MIXED procedures for a completely randomized design with repeated measures (SAS, 2001). The cows were blocked by parity according to expected calving date, and treatment assignments were rotated among cows within a block. The analysis of all time series data was performed using the model Yijk = µ + {alpha}i + ßj + ({alpha}ß)ij + dl({alpha}ißj) + {delta}k + ({alpha}{delta})ik + ({alpha}ß{delta})ijk + eijk where Yijk = dependent variable, µ = dependent variable mean, {alpha}i = effect of treatmenti (i = 1 to 3), ßj = effect of parity (j = 1 or >1), ({alpha}ß)ij = interaction effect between treatment and parity, dl({alpha}ißj) = random effect of cow, {delta}k = effect of sampling at weekk (k = 1 to 17), ({alpha}{delta})ik = interaction effect between treatment and time, ({alpha}ß{delta})ijk = interaction effect between treatment, parity, and week, and eijk = residual error term. Milk yield for wk 1 and 2 was used as a covariant to calculate adjusted yields of milk and FCM when the data were separated according to parity of cows. Data for primiparous and multiparous cows also were compared by selected interaction contrasts. Statistical significance was declared at P < 0.05.

Experiment 3.
All data were statistically analyzed using the PROC MIXED procedure in SAS Version 8.0 (SAS, 2001). All data were normally distributed. A random statement was used to help eliminate some of the variation caused by individual effect of animal. The statistical model used in the serum and whole blood analyses was Y = µ + {alpha}i + ßj + {delta}k + ({alpha}{delta})ik + (ß{delta})jk + eijk where {alpha}i = effect of diet, ßj = age of dam effect, {delta}k = day effect, ({alpha}{delta})ik = interaction effect between diet and day, (ß{delta})jk = interaction effect between age of dam and day, and eijk = experimental error. The statistical model used in liver analysis was Y = µ + {alpha}i + ßj + ({alpha}ß)ij + eij where {alpha}i = effect of diet, ßj = age of dam effect, ({alpha}ß)ij = interaction effect of diet and age of dam, and eij = experimental error. The statement model for VFA analysis was Y = µ + {alpha}i + ei, where {alpha}i = effect of diet and eij = experimental error.


   RESULTS AND DISCUSSION
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
CONCLUSIONS
 REFERENCES
 
Experiment 1.
Body weights of cows fed the control and Co-supplemented diets increased 20 and 78 kg, respectively, during the 60-d feeding period. Concentrations of Co in serum were not affected by dietary Co (P > 0.05; Table 6Go) or age (P > 0.05); however, they increased with time (P < 0.05). No interactions were detected between treatment and sampling date (P > 0.05) or between age and sampling date (P > 0.05). Reported values for Co in serum vary markedly (Young, 1979); however, concentrations above 0.09 mg/kg indicate Co sufficiency (Puls, 1988). Cobalt concentrations in serum were about 0.02 mg/kg greater than for Co in whole blood (values not shown). Cobalt concentrations in liver were similar between treatment groups (P > 0.05; Figure 1Go); thus, supplemental dietary Co did not increase Co storage in the liver. The values of Co in liver were within the sufficient range for cattle (Puls, 1988). However, age significantly (P < 0.01) affected the Co concentration of the liver with the younger cows having more than twice the concentration of Co in liver compared with older cows (Figure 1Go).


View this table:
[in this window]
[in a new window]
  		Table 6. Effect of cobalt supplementation on concentrations of cobalt, copper, and zinc in serum of nonlactating cows (Study 1).
 


View larger version (17K):
[in this window]
[in a new window]
  		Figure 1. Effect of added dietary cobalt and age of cow on the concentration of cobalt in liver (wet wt), study 1. SE = 0.17.

 
Concentrations of Co in serum and liver were significantly (P < 0.05) correlated (r = 0.74). Due to similar serum Co values but much lower concentrations of Co in liver of older cows, concentrations of Co in liver and serum were more highly correlated within age group (r = 0.92 for the younger cows and r = 0.97 for the older cows). Cobalt concentrations in whole blood were also correlated with liver Co (r = 0.77) with much stronger correlations within age group (r = 0.98 for the younger cows and r = 0.97 for older cows).

The percent distribution of Co among the cellular fractions of the liver (Figure 2Go) did not differ (P > 0.05) between the two treatments or age groups; thus, the greater amount of Co within liver of the younger cows was proportionately distributed among all subcellular fractions. The Co content was greatest in the cytosolic fraction, intermediate in the mitochondrial, microsomal, and lysosomal fractions, and least in the nuclear fraction. Both the cytosolic and nuclear fractions were significantly different from all other fractions. The intermediate fractions did not differ significantly from each other.



View larger version (17K):
[in this window]
[in a new window]
  		Figure 2. Percent distribution of cobalt within subcellular fractions of bovine liver, study 1. SE = 0.05.

 
A proportion of Co in liver is associated with vitamin B12 (Underwood, 1956). Cobalt as a component of vitamin B12 has known functions within the cytosolic, mitochondrial, and nuclear fractions. Vitamin B12, as methylcobalamin, is required for methylmalonyl CoA mutase (or isomerase) activity, for conversion of methylmalonyl CoA to succinyl CoA (Baumgartner, 1983). This reaction takes place within the mitochondria (Gimsing and Nexo, 1983). N-Methyltetrahydrofolate:homocysteine methyltransferase uses the methylcobalamin form of vitamin B12 as a coenzyme in the regeneration of methionine from homocysteine, which occurs in the cell cytoplasm (Cooper, 1983; Gimsing and Nexo, 1983). Within the nucleus, vitamin B12 is required for enzymatic reduction of ribonucleotides and for the DNA-methylase enzyme (Schneider and Stroinski, 1987). Increased Co in ruminant diets has been reported to increase the percentage of elemental Co in liver and proportionately reduce Co associated with vitamin B12 (Underwood, 1956). The mechanism by which Co accumulates in the liver is unknown as no Co storage protein has been reported.

Experiment 2.
DMI of lactating cows were affected (P < 0.05) by parity, week, and the interaction of treatment x parity x week of the study (Table 7Go). Yields of milk and 3.5 FCM also were affected by interaction of treatment x parity x week such that milk yields of multiparous cows (42.2, 43.7, and 46.7 kg of 3.5 FCM/d, SE = 1.5, for control, medium, and high Co treatments, respectively) were increased when fed the highest level of supplemental Co. In contrast, yields of milk and 3.5 FCM of primiparous cows (35.8, 34.9, and 36.2 kg of 3.5 FCM/d, SE = 2.8, for control, medium, and high Co treatments, respectively) were not affected, hence the threeway interaction of treatment x time x parity. Although the percent fat and the percent protein in milk was not affected by dietary treatment, yields of fat and protein also were affected by the interaction of treatment x parity x period. Milk production efficiency, calculated as milk energy/intake energy, was not affected by treatment. However, energy balance was affected by the interaction of treatment x parity x time (Table 7Go). Neither BCS nor BW was affected by dietary Co. Concentrations of glucose and NEFA in serum were unaffected by dietary treatments (Table 8Go). Serum concentrations of glucose were lowest at the early postpartum sampling periods and serum NEFA levels were much higher at seven DIM than at 21 d prepartum or 120 DIM (Table 9Go).


View this table:
[in this window]
[in a new window]
  		Table 7. Effect of dietary cobalt supplementation on body weight and condition score, feed intake, and yield of milk and milk components in lactating dairy cows (LSM, Study 2).
 

View this table:
[in this window]
[in a new window]
  		Table 8. Effect of dietary Co supplementation on the concentration of trace elements in serum, whole blood, and liver of lactating cows (Study 2).
 

View this table:
[in this window]
[in a new window]
  		Table 9. Effect of days-in-milk on selected measures in serum of lactating cows (Study 2).
 
Concentrations of Co, Cu, Zn, and Mn in colostrum and milk were not affected by dietary treatments (Table 10Go). However, primiparous cows had significantly higher concentrations of Co in colostrum (0.119 vs. 0.093 µg/ml, respectively) and milk (0.099 vs. 0.082 µg/ml, respectively) compared with multiparous cows. Copper in colostrum, but not milk, was affected by the interaction of treatment x parity.


View this table:
[in this window]
[in a new window]
  		Table 10. Effect of dietary cobalt supplementation on the concentration of trace elements in colostrum and milk (Study 2).
 
There were no effects of dietary treatment on concentrations of Co, Cu, Zn, and Mn in serum (Table 8Go). There was a period effect such that Co concentrations in serum were highest at seven DIM and were subsequently lowest by 120 DIM (Table 9Go), perhaps indicating that secretion of Co into milk was a drain on endogenous Co reserves. Mean concentrations of Co in serum and whole blood were quite close (0.095 µg Co per milliliter of serum and 0.098 µg Co per milliliter of whole blood). Although Co concentrations in whole blood (0.105 vs. 0.096 µg/ml) and serum (0.099 vs. 0.094 µg/ml) were numerically higher in primiparous than multiparous cows, overall, there was not a parity effect because Co concentrations in serum of primiparous cows declined sharply from 7 to 120 DIM. Similar to changes in Co concentrations in serum, there were significant effects of period on concentrations of Cu and Zn in serum (Table 9Go). The concentrations of Zn in liver were similar among treatments (Table 8Go).

Cobalt supplementation did not increase Co in the liver, in fact, concentrations of Co in liver were reduced in cows fed the high Co diets (Table 8Go). Cobalt absorption and tissue retention are very low in ruminants. By use of 60Co, Looney et al. (1976) estimated 95 to 98% of 60Co given orally to sheep was excreted via the feces within 5 d, and a further 0.5 to 2.0% was excreted via the urine. Therefore, supplementation of cows in the current study with 15 to 30 mg of Co per day was unlikely to increase tissue Co significantly within 140 d. Henry et al. (1997) and Kawashima et al. (1997) found significant increases of Co in liver of sheep fed supplemental Co; however, they fed diets supplemented with much higher Co levels (20 and 40 mg/kg Co). Furthermore, if Co retention is only 2% of intake, and Co intake averaged 9, 16, and 30 mg/d for the three treatment groups, then cows were in negative Co balances of about 3.1, 3.0, and 2.7 mg/d, respectively, due to Co secretion into milk (Table 10Go). Although intestinal absorption of Co may have been greater than 2%, it would need to have been at least 37% in control cows to maintain a positive Co balance relative to intake and milk secretion of Co. Although concentrations of Co in liver in primiparous and multiparous cows (2.16 vs. 1.82 µg/g) were not significantly different, the liver samples were taken after 120 DIM and substantial losses of Co from liver for milk secretion may have already occurred. Unfortunately, prepartum concentrations of Co in liver were not measured. However, because a metabolic role for Co that is separate from vitamin B12 is unknown, a negative Co balance may not be harmful to cattle if enough B12 is synthesized in the rumen to meet needs for metabolism, lactation, and gestation.

There was no effect of Co supplementation on concentrations of vitamin B12 in serum of cows (Table 8Go). However, there was a significant effect of week and a significant interaction of parity x week on serum B12 concentrations (Figure 3Go and Table 9Go). Primiparous cows had higher B12 concentrations in serum than multiparous cows (1.81 vs. 0.96 ng/ml). Also, serum B12 concentrations declined from 2.4 ng/ml at 21 d prepartum, to 2.0 ng/ml at seven DIM, to 1.2 ng/ml at 120 DIM. Elliot et al. (1965) previously reported that B12 in blood is reduced in early lactation cows. Reduced blood B12 may be caused by a combination of maternal transfer of B12 to the fetus, colostrum, and milk, and by restricted roughage diets in cows (Walker and Elliot, 1972).



View larger version (15K):
[in this window]
[in a new window]
  		Figure 3. Effect of parity and days in milk on concentration of vitamin B12 in serum, study 2. SE = 0.415 ng/ml.

 
An explanation why lactating primiparous and multiparous cows responded differently to Co supplementation is not clear. There are at least three possible modes of action by which Co could affect ruminant production. First, increased ruminal synthesis and subsequent absorption of vitamin B12 with added dietary Co; second, supplemental Co could increase ruminal fermentation, possibly by an increased vitamin B12 supply to bacterial strains that do not synthesize B12; and third, there may be a possible metabolic role for Co. Results of experiment 1 indicated that endogenous reserves of Co were different between young (2.5 yr) and old (6.5 yr) cows. In experiment 2, primiparous cows at parturition had higher status of Co and vitamin B12, as evidenced by higher Co concentrations in serum, colostrum, milk and higher B12 in serum than did multiparous cows. Concentrations of vitamin B12 and Co in serum decreased in all cows during lactation; thus, milk secretion appeared to be a substantial drain on endogenous reserves of both Co and vitamin B12.

A net balance for vitamin B12 was not calculated for cows in this trial because total daily ruminal synthesis and intestinal absorption of vitamin B12 was not known. Normal concentrations of B12 in milk are 2 to 4 µg/L (Puls, 1988); thus, daily secretion of B12 into milk was probably between 72 and 144 µg/d. Blood concentrations of vitamin B12 were depressed during the initial 120 DIM, indicating B12 absorption probably was less than need for B12, including secretion into milk. Because milk secretion represents such a large output of vitamin B12 and Co, replenishment of endogenous reserves of these nutrients needs to occur largely during the dry period, however, and their intestinal absorption is low.

Experiment 3.
Average daily feed intakes were greater (P < 0.01) for calves fed the control starter (1.79 vs. 1.62 kg/d, respectively, SE = 0.06). During the 12-wk period, average intakes of Co were 1.13 mg/d for the unsupplemented calves and 2.17 mg/d for the calves consuming the starter supplemented with cobalt. If a value of 0.09 mg Co per kilogram of milk is assumed (Table 10Go), the calves consumed about 0.2 mg Co per day for the first 4 wk and about 0.1 mg of Co per day during wk 5 and 6 from the milk. Average daily gains (0.74 kg/d) were similar (P > 0.05) for calves fed either starter.

Calves fed the control starter had higher concentrations of Co in serum than calves fed the Co-supplemented starter. The reason for this is unclear. Calves of primiparous dams had a tendency (P = 0.14) for higher serum Co concentrations than calves of multiparous cows. Week of treatment had a significant effect on serum Co concentrations (P < 0.01) with increased serum Co concentrations at wk 6 of treatment followed by a decline at wk 12. This may be due, at least in part, to absorption of Co from the milk, or possibly reflect higher intestinal absorption efficiency of Co in preweaned calves.

Cobalt concentration in liver was not affected by either Co supplementation (P > 0.05) or the age of calf’s dam (P > 0.05). Calves fed the Co-supplemented diet had average liver Co concentrations of 5.18 mg/kg (wt/wt) compared with 4.26 mg/kg (wt/wt) in calves fed the control starter. Concentrations of Co in serum and liver were poorly correlated (r = 0.28) although correlations were somewhat higher within treatment groups (r = 0.42 for control calves and r = 0.53 for Co-supplemented calves). The concentrations of Co in liver of the calves in this study are much higher than the Co concentrations in liver of Holstein cows in experiments 1 and 2. Thus, Co concentration in liver appears to decline with age in dairy cattle.

Concentrations of Co in whole blood did not differ (P > 0.05) between treatment groups. Cobalt concentration in whole blood was lower than in serum at wk 0 and 6 for calves consuming the unsupplemented starter but greater than serum cobalt concentration at wk 12 and in the calves consuming the supplemented starter. This may be due to greater variation of Co concentrations in serum than erythrocytes (Young, 1979).

Rumen fluid of calves was analyzed for VFA as an indication of effects on ruminal fermentation. Previously, Allen (1986) reported 10 mg/kg dietary Co increased cellulose digestibility in vitro of diets containing 40% forage, 60% concentration. Likewise, Co supplementation may increase propionate production by certain ruminal bacteria that are dependent upon vitamin B12 in order to convert succinate to propionate (Strobel, 1992). However, there was no effect (P > 0.05) of Co supplementation on the ratio of acetate to propionate in ruminal fluid of calves at 12 wk of age. Average molar concentrations of propionate in ruminal fluid were 49.6 and 50.8 µm/L (SE = 1.21) for control and supplemented calves, respectively. The concentration of acetate in ruminal fluid was 65.0 and 72.8 µm/L (SE = 1.00), respectively, for calves fed the control and Co-supplemented starter.

The decline in concentration of Co in liver of cattle with age is not entirely unique among trace elements; in fact, metabolism of Co has several similarities to chromium metabolism. Chromium concentration declines in most tissues (except lungs) as animals age (Anderson, 1987). In a manner similar to Co, Cr+3 also is poorly absorbed (0.5 to 2%) and is probably transported using Fe-binding proteins in blood (Offenbacher et al., 1997). In addition, the biologically active forms of Co (vitamin B12) and Cr (glucose tolerance factor) are organic complexes, and there is no known biological activity for either inorganic element.


   CONCLUSIONS
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS
REFERENCES
 
The concentration of Co in serum, whole blood, liver and subcellular distribution of Co in liver of cattle was not affected by Co supplementation in these studies. Within liver, nearly 40% of the Co was present in the cytoplasm. The concentration of Co in liver did not affect the subcellular distribution of Co. Age of the animal affected the concentration of Co in liver with the highest concentrations in young calves and higher concentrations in younger than older cows. The decline of Co in liver with age of cattle may be due to a combination of low intestinal absorption, endogenous losses, and Co secretion into milk. However, no effects due to loss of Co from liver with age are known. Thus, further research appears to be needed on the effects of Co supplementation on ruminal fermentation and metabolism of dairy cattle.


   FOOTNOTES
 
1 Appreciation is expressed to Zinpro Corp., Eden Prairie, MN, for partial funding support for this study. The use of trade names and/or products in this publication does not imply endorsement or criticism of those products. Back

Received for publication August 12, 2002. Accepted for publication October 26, 2002.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS
 REFERENCES
 


Allen, M. 1986. Effects of cobalt supplementation on carbohydrate and nitrogen utilization by ruminal bacteria in continuous culture. M.S. Thesis. Univ. Minnesota, St. Paul.

Anderson, R. A. 1987. Chromium in Trace Elements in Human and Animal Nutrition, 5th ed. W. Mertz, ed. Academic Press, Inc., New York, NY.

Association of Official Analytical Chemists. 1990. Official Methods of Analysis. Vol. 1. 15th ed. AOAC, Arlington, VA.

Baumgartner, R. 1983. Activity of the cobalamin-dependent methylmalonyl-CoA mutase. Pages 181–195 in Methods in Hematology: The Cobalamins. C. H. Hall, ed. Churchill Livingstone, New York, NY.

Chen, C. Y., P. Zhang, X. L. Hou, and Z. Chai. 1999. Investigation of selenium distribution in subcellular fractions of human liver by neutron activation analysis. Biol. Trace Elem. Res. 71–72:131–138.

Cooper, B. A. 1983. The assay of cobalamin-dependent enzymes: Their utilization for evaluation of cobalamin metabolism. Pages 165–180 in Methods in Hematology: The Cobalamins. C. H. Hall, ed. Churchill Livingstone, New York, NY.

Dryden, L. P., and A. M. Hartman. 1971. Variations in the amount and relative distribution of vitamin B12 and its analogs in the bovine rumen. J. Dairy Sci. 54:235–246.

Elliot, J. M., E. P. Barton, and J. A. Williams. 1979. Milk fat as related to vitamin B12 status. J. Dairy Sci. 62:642–645.

Elliot, J. M., D. E. Hogue, and H. F. Tyrrell. 1965. Blood vitamin B12 status of the dairy cow in late pregnancy and early lactation. J. Dairy Sci. 48:1335–1338.

Gimsing, P., and E. Nexo. 1983. The forms of cobalamin in biological materials. Pages 7–30 in Methods in Hematology: The Cobalamins. C. H. Hall, ed. Churchill Livingstone, New York, NY.

Henry, P. R., R. C. Littell, and C. B. Ammerman. 1997. Bioavailability of cobalt sources for ruminants. 1. Effects of time and dietary cobalt concentration on tissue cobalt concentration. Nutr. Res. 17:947–955.

Kawashima, T., P. R. Henry, C. B. Ammerman, R. C. Littell, and J. Price. 1997. Bioavailability of cobalt sources for ruminants. 2. Estimation of the relative value of reagent grade and feed grade cobalt sources from tissue cobalt accumulation and vitamin B12 concentrations. Nutr. Res. 17:957–974.

Looney, J. W., G. Gille, R. L. Preston, E. R. Graham, and W. H. Pfander. 1976. Effects of plant species and cobalt intake upon cobalt utilization and ration digestibility by sheep. J. Anim. Sci. 42:693–698.

McDowell, L. R. 1992. Minerals in Animal and Human Nutrition. Academic Press, Inc., San Diego, CA.

Mills, C. F. 1981. Cobalt deficiency and cobalt requirements of ruminants. Pages 129–140. In: W. Haresign, Ed. Recent Advances in Animal Nutrition. Butterworths, Boston, MA.

National Research Council. 2001. Nutrient Requirements of Dairy Cattle. 7th rev. ed. Natl. Acad. Sci., Washington, DC.

Offenbacher, E. S., F. X. Pi-Sunyer, and B. J. Stoecker. 1997. Chromium in Handbook of Nutritionally Essential Mineral Elements. B. L. O’Dell and R. A. Sunde, eds. Marcel Dekker, Inc., New York, NY.

Puls, R. 1988. Mineral Levels in Animal Health. Trinity Western University Press. British Columbia, Canada.

Robinson, J. W. 1975. Atomic Absorption Spectroscopy, 2nd edition. Marcel Dekker, Inc., New York, NY.

SAS. User’s Guide, Version 8.1, 1st edition. SAS Inst. Inc., Cary, NC.

Schneider, Z. and A. Stroinski. 1987. Comprehensive B12. Walter deGruyter Inc. Hawthorne, NY.

Smith, R. M. and H. R. Marston. 1970. Production, absorption, distribution, and excretion of vitamin B12 in sheep. Brit. J. Nutr. 24:857–867.[Medline]

Strobel, H. J. 1992. Vitamin B12-dependent propionate production by the ruminal bacterium Prevotella ruminicola23. Appl. Environ. Microbiol. 58:2331–2333.[Abstract/Free Full Text]

Sutton, A. L., and J. M. Elliot. 1972. Effect of ratio of roughage to concentrate and level of feed intake on ovine ruminal vitamin B12 production. J. Nutr. 102:1341–1346.

Underwood, E. J. 1956. Trace Elements in Human and Animal Nutrition. Academic Press, Inc. New York, NY.

Underwood, E. J., and N. F. Suttle. 1999. Cobalt in: The Mineral Nutrition of Livestock. CABI Publishing, New York, NY.

Walker, C. K., and J. M. Elliot. 1972. Lactational trends in vitamin B12 status on conventional and restricted-roughage rations. J. Dairy Sci. 55:474–479.

Wapnir, R. A. 1990. Protein Nutrition and Mineral Absorption. CRC Press, Inc., Boca Raton, FL.

Young, R. S. 1979. Cobalt in Biology and Biochemistry. Academic Press, Inc., San Francisco, CA.


This article has been cited by other articles:


Home page
 J DAIRY SCIHome page
R. L. Kincaid and M. T. Socha
Effect of Cobalt Supplementation During Late Gestation and Early Lactation on Milk and Serum Measures
J Dairy Sci, April 1, 2007; 90(4): 1880 - 1886.
[Abstract] [Full Text] [PDF]

Home page
 J DAIRY SCIHome page
J. E. Nocek, M. T. Socha, and D. J. Tomlinson
The effect of trace mineral fortification level and source on performance of dairy cattle.
J Dairy Sci, July 1, 2006; 89(7): 2679 - 2693.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Kincaid, R. L.
Right arrow Articles by Johnson, A. B.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Kincaid, R. L.
Right arrow Articles by Johnson, A. B.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS