Effect of iodine, selenium and cobalt rumen boluses given to dry dairy cows on the immunoglobulin and thyroid hormone status of calves

O R I G I N A L A R T I C L E

Effect of iodine, selenium and cobalt rumen bolusesgiven to dry dairy cows on the immunoglobulin andthyroid hormone status of calvesasj_991 1..6

Michael ROSE, Sam PEARSON and Tom CRATCHLEY

Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Ceredigion, UK

ABSTRACT

The objective was to determine the effect of rumen boluses containing 6800 mg iodine, 1000 mg selenium and 1000 mg

cobalt given to dry dairy cows on the efficiency of colostral immunoglobulin G (IgG) absorption in calves. Thirteen cows

received the bolus approximately 58 days before calving. A further 12 cows received no bolus and were used as controls.

The cows were housed as one group. Calves were prevented from suckling for the first 24 h of life, and were given three

feeds of a fixed quantity of colostrum. At 24 h, the average plasma concentrations of IgG in the calves were 15.5 and

13.4 g/L for the control and bolus groups, respectively; these were not significantly different (P = 0.212). Bolus treatment

was associated with higher levels of free and total tri-iodothyronine (T3) and thyroxine (T4) in the dams (all P < 0.001),

although it had no effect on thyroid hormone levels in the calves. There were nevertheless positive and negative

relationships between the efficiency with which colostral IgG was absorbed at 24 h and, respectively, total T3 at 24 h

(P < 0.05) and total T4 at 1 h of age (P < 0.05). The underlying basis for these relationships remains to be established.

Key words: cattle, colostrum, immunoglobulin-G, iodine, passive immunity.

INTRODUCTIONAdequate immunoglobulin (Ig) absorption from colos-trum is critical for the subsequent health of neonatalruminants. Circulating concentrations of Ig belowapproximately 10 g/L at 24 h of age are associatedwith increased incidences of mortality (Donovan et al.1998). Colostrum consumption must occur during thefirst hour of life; beyond approximately 6 h of age thegut gradually loses its ability to take up colostral Ig anddeposit it into the lymphatic system, and the process isessentially complete in calves by approximately 24 hof age (Stott et al. 1979).

It has been noted that when individually housedpregnant ewes were given unlimited access to mineralblocks, the circulating IgG concentrations in the lambswere 36% of values for control ewes having receivedno mineral block (Crosby et al. 2004). Later workidentified iodine as the mineral component of theblocks that causes impaired absorption of colostral IgG(Boland et al. 2005). This effect occurs in the lambs ofpregnant ewes fed iodine as low as 14.8 mg/day (Roseet al. 2007). The excessive iodine intake by pregnantewes is thought to cause a change in the thyroidhormone status of the lambs, prior to, or around thetime of birth, possibly reducing the period of time over

which the gut is open to the transport of Ig (Cabelloet al. 1980). However, this phenomenon has not beeninvestigated for iodine administered to dry dairy cowsand their calves even though iodine, selenium andcobalt are routinely given on commercial farms todairy cows in their dry period. Accordingly, the objec-tive of the present experiment was to determine if theuse of a bolus treatment containing iodine, seleniumand cobalt, used in accordance with the manufactur-er’s instructions, impaired the concentration of IgGin calves.

MATERIALS AND METHODSAnimals, feeds and experimentaltreatmentsAll animal experimentation was approved by the Aberystw-yth University Ethical Review Committee and was done in

Correspondence: Michael Rose, Institute of Biological, Envi-ronmental and Rural Sciences, Aberystwyth University,Ceredigion SY23 3DA, UK. (Email: [email protected])Received 10 August 2011; accepted for publication 26 Sep-tember 2011.

Animal Science Journal (2012) doi: 10.1111/j.1740-0929.2011.00991.x

© 2012 The AuthorsAnimal Science Journal © 2012 Japanese Society of Animal Science

compliance with the UK Animals (Scientific Procedures) Act,1986. Thirty-eight multiparous, dry Holstein-Friesian cowswere used in the study. The cows were predicted to calvebetween 12 September and 16 October, 2009 and were driedoff between 10 May and 14 June 2009. The cows wereallocated equally to one of two groups (control and bolus),which were balanced for parity, previous milk yield and bodycondition score (BCS). Forty days before calving was due tobegin a 10 mL blood sample was taken from the coccygealvein of all cows using an evacuated test tube. The cows in thebolus group were then immediately given two boluses con-taining a total of 6800 mg of iodine, 1000 mg of seleniumand 1000 mg of cobalt (Tracesure I, Animax Limited, Bury StEdmunds, UK). The average period between bolusing andcalving (� standard error (SE)) was 58 � 7.8 days. Thecontrol cows were given no bolus and calved on average56 � 8.7 days later. A further blood sample was taken fromall cows 20 days before the predicted start of calving.

At the point of bolusing the cows, their average weight andBCS (� SE) was 641 � 15.9 kg and 3.05 � 0.1, respectively;these were not significantly different between the twogroups. Prior to drying off, the cows were at grass. Followingdrying-off the cows were then housed in free-stalls. Forthe bulk of the dry period, the cows were fed a total mixedration (Far-TMR) that was changed for another (Near-TMR)approximately 2 weeks before the predicted calving date; theingredients of the diets are shown in Table 1 and the analysisof the diets, from samples taken each week and bulked, isshown in Table 2. The cows were housed as one group andwere offered the diets on an ad libitum basis. Intakes of thediet were not recorded. Fresh water was freely available at alltimes. The crude protein, acid detergent fibre, neutral deter-gent fibre, ether extract and ash contents of the feeds were

determined (AOAC 1996). The iodine, selenium and cobaltcontents of the feed were also determined (Robinson 1975;Vanhoe et al. 1993).

Prior to calving, 250 L of first milking colostrum was col-lected in three batches of approximately 100, 75 and 75 Lfrom other cows calving on the same farm. Within batches,the colostrum was bulked, mixed and then frozen in 1 L lots.The IgG concentrations in the three batches were 69.0 g/L,76.7 g/L and 74.4 g/L, respectively. The batches of colostrumwere distributed evenly between the control and boluscalves. The cows providing the colostrum were on the samediet described above.

CalvingFollowing calving, the cows were left with their calves forapproximately 45 min. Before the calf was able to suckle, itwas weighed, had its navel disinfected, and was then movedto a separate calf pen. A 10 mL jugular vein blood samplewas then taken from the calf. Following this, the calves werebottle-fed 2 L of the previously stored bulked colostrum,warmed to 40°C. Any refusals were noted, and werere-offered to the calf 30 min later. The colostrum was thenadministered by gastric tube if a calf continued to refuse tosuckle. Two further meals of colostrum of 2 L and then 1 Lwere offered to the calves at 6 and 12 h after birth, respec-tively. Each calf received an average of 366.8 g of IgG duringthe first 24 h. This is thought sufficient to minimize thechances of disease (Quigley 2007). At 24 h after birth afurther jugular vein blood sample was taken from the calves.The milk yield, concentrations of milk fat and protein, theBCS and body weight of the cows was recorded each weekfor the first 6 weeks of lactation. The incidence of metritis(purulent uterine discharge in the vagina within 21 days postpartum) and endometritis (purulent uterine discharge in thevagina more than 21 days post partum (Sheldon et al. 2006))after calving were determined by visual inspection with a vettwice per week. A cow was considered to have the conditionif the signs were observed on two sequential occasions.

Of the 38 pregnant cows that started the trial, data wascollected from 25 of the calves and 34 of the cows; 12 calvesand 18 cows from the control group, and 13 calves and 16cows from the bolus-treated group. The data from 13 calveswere not used for the following reasons: three cows calvedearlier than predicted and were missed; one cow aborted;two cows gave birth to calves that died during calving; onecalf, after a difficult calving, was considered too weak to beused; six cows calved later than predicted and data could notbe collected. The data from four cows were not used for thefollowing reasons: one cow aborted and was considered tooill to be used; three cows calved too late to be included inthe trial.

Plasma sample analysisBlood samples were mixed with heparin and centrifugedat 1500 ¥ g for 30 min within 2 h of collection. Plasma wasfrozen at -20°C until further analysis. Using commerciallyavailable ELISA kits and according to the respective manu-facturer’s instructions, all plasma samples were analyzedfor free tri-iodothyronine (T3; MP Biochemicals, New York,NY, USA), total (bound and free) T3 (MP Biochemicals),free thyroxine (T4; MP Biochemicals), and total T4 (MPBiochemicals). Plasma samples from the calves onlywere analyzed for bovine IgG using a sandwich ELISA(Alpha Diagnostic, San Antonio, TX, USA). The intra-assay

Table 1 Far-TMR and Near-TMR diet ingredients

Far-TMR(g/kg DM)

Near-TMR(g/kg DM)

Chopped barley straw 300 260Grass silage 220 180Rolled barley 190 160Brewer’s grains 140 120Bread waste 70 50Dry cow concentrate 0 150Sugar beet pulp 40 40Dry cow mineral blend 40 40

TMR, total mixed ration; DM, dry matter.

Table 2 Far-diet and near-diet analyses (g/kg DM, unlessstated otherwise)

Far-diet Near-diet

Iodine (mg/kg DM) 1.89 2.62Selenium (mg/kg DM) 0.07 0.08Cobalt (mg/kg DM) 0.25 0.31Dry matter (g/kg FW) 487 532Crude protein 116 128Acid detergent fibre 286 258Neutral detergent fibre 524 488Ether extract 25 28Ash 92 87

DM, dry matter; FW, fresh weight.

2 M. ROSE et al.


Animal Science Journal (2012)

coefficients of variation for all assays were less than 7.1%,and the inter-assay coefficients of variation for all assays wereless than 10.8%.

Calculations and statisticsThe apparent efficiency of IgG appearance in the bloodwas calculated assuming that the plasma of blood innewborn calves is 75 mL/kg (Quigley 2007; Rose et al. 2007).Hormone and IgG data were analyzed by analysis of variancefor repeated measures, using Genstat statistical software(version 10.1, Lawes Agricultural Trust, Rothamsted, UK);the fixed effect was treatment group and the time effect wasbefore and after the bolus administration for the cow plasmasamples, or 1 h and 24 h of age for the calf samples. Leastsquares means are presented. The significance of the differ-ence between individual means was determined using a leastsignificant difference test when the interaction betweentreatment and time was significant. IgG absorption efficiency,amount of IgG fed, calf birth weight, cow milk yield and milkcomponents, and cow BCS and weight post partum datawere analyzed with a two-tailed unpaired Student’s t-test.The efficiency of IgG absorption in the calves at 24 h wasregressed linearly against concentrations of thyroid hor-mones in the cows before and after the bolus administration,as well as in the calves at 1 h and 24 h of age. Finally, theincidence of metritis and endometritis were analyzed usinga Chi-squared test with Yates’s correction. Throughout, sig-nificance was declared when the probability of there beingno difference between the means (or, for the regressions, nodifference between the gradient of the line and zero) fellbelow 0.05.

RESULTSImmunoglobulin G was undetectable in the calvesimmediately prior to the feeding of colostrum, whilelevels were very much higher at 24 h of age

(P < 0.001). There was no effect of the bolus treatmenton the concentration of IgG in the plasma of the calves(P = 0.212), nor was there any interaction betweentime and bolus treatment (P = 0.212; Table 3). Theconcentrations of free T3, free T4 and total T4 in thecalves were greater at 24 h of age relative to the valuesobserved at 1 h (all P < 0.001), although there was noeffect of time on total T3 (P = 0.709). There was noeffect of the bolus treatment of the dams on the calfconcentrations of any of the thyroid hormones mea-sured (all P > 0.1), nor were there any significantinteractions between bolus treatment and time (allP > 0.1; Table 3). With respect to the plasma concen-trations of thyroid hormones in the dams, there wereinteractions between bolus treatment and time forthe plasma concentrations of free and total T3 and T4,such that levels of all four measures were highest inthe bolus-treated cows after the bolus treatment (allP < 0.05; Table 4).

There was a significant positive correlation betweenthe plasma concentration of free T3 in cows beforebolusing and the efficiency of uptake of colostral IgGby calves (P < 0.05); that is, dams with the highest T3concentration before the bolusing, regardless of thebolus treatment that cows received, had calves with agreater efficiency of colostral IgG absorption (Table 5).There was a significant positive correlation betweenthe concentration of total T3 in the calves at 24 h ofage and the efficiency of colostral IgG absorption(P < 0.05); this relationship also approached signifi-cance for total T3 concentrations in the calves at 1 h ofage (P < 0.1; Table 5). There was a negative relation-ship between total T4 concentrations in the calves at

Table 3 Calf plasma concentrations of free and total T3 and T4 from cows given boluses of iodine, selenium and cobaltapproximately 8 weeks prior to calving (bolus) or no treatment (control)

Control Bolus SED† P (treatment) P (time) P (time ¥treatment)

1 h 24 h 1 h 24 h

IgG (mg/L) 0.0 15.5 0.0 13.4 1.11 0.212 < 0.001 0.212Free T3 (ng/L) 5.6 8.1 4.0 8.4 1.31 0.546 < 0.001 0.128Total T3 (ng/L) 4900 4280 3840 3920 898 0.766 0.709 0.117Free T4 (ng/L) 10.7 19.5 11.3 21.9 2.97 0.525 < 0.001 0.597Total T4 (mg/L) 153.3 204.8 153.4 235.6 19.30 0.322 < 0.001 0.182

†Maximum standard error of the difference between means.

Table 4 Concentrations of free and total T3 and T4 in cows before and after they were treated with iodine, selenium andcobalt boluses (bolus) or no treatment (control)

Control Bolus SED† P (treatment) P (time) P (time ¥treatment)

Before After Before After

Free T3 (ng/L) 3.29b 2.83b 3.64ab 4.42a 0.471 0.211 0.192 < 0.001Total T3 (ng/L) 4890b 7180b 5770b 13 690a 1703 0.017 < 0.001 0.003Free T4 (ng/L) 12.07ab 11.73b 12.26ab 15.79a 1.91 0.474 0.655 0.033Total T4 (mg/L) 188.2ab 159.7b 191.7ab 228.6a 22.99 0.052 0.838 0.029

†Maximum standard error of the difference between means. abcMeans within rows with different superscripts are significantly different(P < 0.05).

IODINE AND IMMUNOGLOBULIN STATUS OF CALVES 3



1 h of age and the efficiency of colostral IgG absorption(P < 0.05); this relationship also approached signifi-cance for the total T4 concentrations at 24 h of age(P < 0.1; Table 5). All other correlation coefficientsbetween the other thyroid hormone measures and theefficiency of colostral antibody absorption were notsignificant (Table 5).

The amount of IgG fed to the calves in the twogroups was not different (360.1 and 373.6 g for thecontrol- and bolus-treated groups, respectively, stan-dard error of the difference (SED): 46.4; P = 0.773),nor was the efficiency of absorption of IgG differentbetween the groups (0.139 and 0.125 g/kg bodyweight, respectively, SED: 0.012; P = 0.449). The birthweight of the calves was not different between thegroups (44.5 and 43.1 kg, respectively, SED: 1.87;P = 0.445). The milk yield of the cows during the first6 weeks of lactation was not affected by the bolustreatment (33.1 and 32.7 kg/d, respectively, SED: 2.11;P = 0.847), nor did the bolus treatment affect the con-centration of fat or protein in milk (results not shown).The average body condition score and body weightof the cows during the first 6 weeks of lactation wasalso not affected by the bolus treatment (results notshown).

Four out of 18 of the control cows and 2/16 of thebolus-treated cows had metritis in the first 6 weeksof lactation. These incidences were not significantlydifferent (P = 0.770). Meanwhile, 9/18 of the controlcows and 3/16 of the bolus-treated cows hadendometritis. Again, these were not significantly dif-ferent (P = 0.123).

DISCUSSIONThe administration of a bolus containing iodine, sele-nium and cobalt to dry pregnant dairy cows approxi-mately 8 weeks before parturition had no effect onthe plasma concentration of IgG or on the efficiency ofabsorption of IgG by calves during the first day of life.This is an important result because it has been shownthat iodine given to late pregnant ewes suppressesthe efficiency of colostral antibody absorption inlambs (Crosby et al. 2004; Rose et al. 2007; Boland et al.2008). As far as the authors are aware, this is the first

time this has been investigated in cattle, and suggestthat the commercial use of boluses containing iodineat this rate does not affect the immune status of calves.

In sheep, dietary iodine at 14.8 mg/day (equivalentto 0.62 mg/kg0.75/day) was sufficient to cause a signi-ficant reduction in colostral antibody absorption insheep, while a rate of 9.9 mg/day (0.41 mg/kg0.75/day)in the same experiment did not (Rose et al. 2007). Themanufacturer of the boluses used in the presentexperiment suggests that the rumen degradationand delivery of iodine is constant for 16 weeks afteradministration (Animax Tracesure-I product litera-ture). Assuming that the iodine in the boluses wasdelivered at a constant rate over 16 weeks, it was56.7 mg/day (equivalent to 0.44 mg/kg0.75/day) duringthe period leading up to parturition. When expressedon a metabolic body weight basis, this is a similar rateto that which did not cause a significant effect in preg-nant ewes (Rose et al. 2007) and so the present studyin cattle probably does not contradict our earlier studyin sheep. Nevertheless, it is also the case that theremay be a difference with respect to this phenomenonbetween cattle and sheep.

Even though the bolus treatment did not affect theIgG status of the calves, there was nevertheless a posi-tive relationship between the efficiency of IgG absorp-tion at 24 h of age, and the total T3 concentration at24 h of age on the one hand, and a negative relationshipbetween efficiency of IgG absorption and total T4 con-centration at 1 h of age, on the other. In anotherexperiment, T3 and T4 were given orally to new-borncalves in their first meal of colostrum (Slebodzinskiet al. 1995), and it was noted that both of these treat-ments increased the concentrations of T3 in the calves.However, the administration of T4 tended to reducethe amount of Ig absorbed by the calves, whilethe administration of T3 significantly increased theabsorption of colostral Ig. Additionally, it has beennoted that an elevated level of T4 in lambs aroundthe time of parturition was negatively associated withthe period over which colostral antibodies may beabsorbed (Cabello & Levieux 1978). Interestingly,iodine supplied to growing angora goats at approxi-mately 0.27 mg/day has been shown to increase plasmaT4, while also decreasing plasma concentrations of T3

Table 5 Simple correlation coefficients between the efficiency of absorption of IgG by calves, and the concentrations of freeand total T3 and T4 in their dams before and after an iodine, selenium and cobalt bolus, and in the calves at 1 and 24 h ofage

Cows Calves

Before bolusing After bolusing 1 h of age 24 h of age

Free T3 (ng/L) +0.447* -0.073 +0.148 +0.267Total T3 (ng/L) +0.349 +0.148 +0.346 +0.398*Free T4 (ng/L) +0.280 -0.109 -0.348 -0.100Total T4 (mg/L) +0.335 -0.216 -0.465* -0.360

*Probability of correlation coefficient significantly different to zero (P < 0.05).

4 M. ROSE et al.



(Wichtel et al. 1996). In the present experiment, whilethe bolus treatment did not significantly affect any ofthe plasma thyroid hormone concentrations in thecalves, the negative and positive relationships betweencirculating T3 at 24 h and T4 at 1 h of age, respectively,and the subsequent efficiency of the absorption ofcolostral IgG, do not contradict any of these findings.Nevertheless, the reason why T3 and T4 appear to workantagonistically with regard to the absorption of colos-tral IgG, and the underlying mechanisms for this,remains to be understood. This clearly warrants furtherinvestigation.

Circulating T3 primarily arises from the de-iodination of T4 by a selenium-containing enzyme,type 1 iodothyronine 5′-deiodinase (Voudouri et al.2003). The inter-relationships between the compo-nents of the thyroid hormone cascade are complex,and it could well be that other metabolites, forexample reverse T3 (rT3) or other enzymes are alsoinvolved. It has been suggested that increased conver-sion of T4 to rT3 or a decrease in the ability to degraderT3 could result in the lower T3 concentrationsobserved when high doses of iodine are given to rumi-nants (Boland et al. 2008). This is because T3 and rT3are reciprocally related due to the inhibitory action ofrT3 on the activity of the enzyme type 1 iodothyronine5′-deiodinase; this enzyme is responsible for both theconversion of T4 into T3 and the degradation ofrT3 into 3,3′ di-iodothyronine (Todini 2007). Thus,elevated levels of rT3 will cause a simultaneousdecrease in the conversion of T4 into T3, and adecrease in the degradation of rT3, further increasingrT3 levels and bringing about lower levels of T3.Because of the absence of a commercial kit for theanalysis of rT3, it was not possible to measure rT3levels in the samples of the present experiment and totest this hypothesis, although this is again clearlyworth further investigation.

A deficiency of selenium has been shown to slowthe conversion of T4 into T3 in sheep (Voudouri et al.2003). Selenium was present in the blended mineralmix given to all cows and therefore a deficiency ofselenium, per se, seems unlikely to be the cause of therelationships between total T3, total T4 and plasmaIgG, even though additional selenium was also presentin the bolus. Iodine, selenium and cobalt boluses wereused in the present study because they were a conve-nient means of delivering an equal amount of iodineto all cows. Unfortunately, boluses that containediodine only were not available to us. Previous work(Boland et al. 2005) has shown that it is iodine andnot the selenium or cobalt that inhibits the uptake ofIgG in newborn lambs. However, the administrationof 400 mg of sodium selinite and 1200 mg of calciumiodide, 20–35 days before calving of pregnant cowswas associated with a positive IgG status of the calveswhen they were born (Gilles et al. 2009), and raising

the possibility that the iodine, selenium and cobaltdelivered to the cows in the present study may havehad multiple effects separate to the effect of the iodinealone; it cannot therefore be excluded that any effectof the iodine on immune status of the calves wasconfounded by an opposite effect of the selenium orcobalt. We are not aware of any reports that note aneffect of cobalt (or vitamin B12) administered to thedam on the immune status of calves.

The concentration of iodine recommended for preg-nant and lactating dairy cattle is reported to be 0.4 mgand 0.45 mg iodine/kg dry matter, respectively (NRC2001). These values are below the levels in boththe Far-TMR and Near-TMR. Indeed, concentrationsof plasma total T3 and T4 that are said to indicateiodine deficiency in pregnant cattle are approximately1300 ng/L and 19 mg/L, respectively (Suttle 2010).These values are lower than the values observed in thepresent experiment, suggesting that the cows were notiodine deficient.

The incidence of metritis and endometritis wasnot significantly affected by the bolus treatments. Theadministration of the same boluses as used here hasbeen shown to improve some aspects of uterine health(Cook & Green 2007). Indeed, in the present study,bolus administration was associated with a numeri-cally lower rate of endometritis (9/18 of control cowsand 3/16 of bolus cows contracted the disease), eventhough this was not significant. It is likely that agreater number of animals than used here would beneeded in order to demonstrate a significant effectwith respect to this.

In conclusion, treating pregnant cows approxi-mately 57 days before parturition with rumen bolusescontaining iodine, selenium and cobalt, according tocommercial practice, had no effect on the plasma con-centration of IgG in the calves after they had con-sumed a standard amount of colostrum. Nevertheless,a positive relationship was found between the effi-ciency of IgG absorption in the calves and plasma T3concentration at 24 h of age, and a negative relation-ship between efficiency of IgG absorption and total T4concentration at 1 h of age, regardless of bolus treat-ment. The complex relationships between metabolitesof the thyroid hormone cascade may be responsible forsome of these relationships.

ACKNOWLEDGMENTSThe authors would like to thank Dr Debbie Nashand Mr Brian Davies, Mr Sam Pearson and Mr TomCratchley for help with the blood collection and for thelaboratory analyses.

REFERENCESAOAC. 1996. Official Methods of Analysis, 16th edn. Associa-

tion of Official Analytical Chemists, Arlington, TX.

IODINE AND IMMUNOGLOBULIN STATUS OF CALVES 5



Boland TM, Brophy PO, Callan JJ, Quinn PJ, Nowakowski P,Crosby TF. 2005. The effects of mineral supplementationto ewes in late pregnancy on colostrum yield and immu-noglobulin G absorption in their lambs. Livestock Produc-tion Science 97, 141–150.

Boland TM, Hayes L, Sweeney T, Callan JJ, Baird AW, KeelyS, Crosby TF. 2008. The effects of cobalt and iodinesupplementation of the pregnant ewe diet on immuno-globulin G, vitamin E, T-3 and T-4 levels in the progeny.Animal 2, 197–206.

Cabello G, Levieux D. 1978. Effects of thyroxine and climaticfactors on colostral gammaglobulin absorption innewborn calves. Annales De Recherches Veterinaires 9, 309–318.

Cabello G, Levieux D, Lefaivre J. 1980. The effect of intra-amniotic injections of thyroxine on the absorptionof colostral igg1 by the newborn kid. British VeterinaryJournal 136, 193–194.

Cook JG, Green MJ. 2007. Reduced incidence of retainedfetal membranes in dairy herds supplemented withiodine, selenium and cobalt. Veterinary Record 161, 625–626.

Crosby TF, Boland TM, Brophy PO, Quinn PJ, Callan JJ,Joyce D. 2004. The effects of offering mineral blocksto ewes pre-mating and in late pregnancy on blockintake, pregnant ewe performance and immunoglo-bulin status of the progeny. Animal Science 79, 493–504.

Donovan GA, Dohoo IR, Montgomery DM, Bennett FL.1998. Associations between passive immunity andmorbidity and mortality in dairy heifers in Florida, USA.Preventive Veterinary Medicine 34, 31–46.

Gilles A, Lebreton P, Troegeler-Meynadier A. 2009. Effects ofa selenium and iodine supplementation of pregnant cowon the newborn calf mineral and immune status. Revue DeMedecine Veterinaire 160, 10–17.

NRC. 2001. Nutrient Requirements of Dairy Cattle, 7th revisededn. National Academy Press, Washington, DC.

Quigley J. 2007. Passive Immunity in Newborn Calves. Universityof Alberta, Deptment of Agricultural. Food and NutritionalScience, Edmonton, AB.

Robinson J. 1975. Atomic Absorption Spectroscopy, 2nd edn.Dekker, New York.

Rose MT, Wolf BT, Haresign W. 2007. Effect of the level ofiodine in the diet of pregnant ewes on the concentrationof immunoglobulin G in the plasma of neonatal lambsfollowing the consumption of colostrum. British Journal ofNutrition 97, 315–320.

Sheldon IM, Lewis GS, LeBlanc S, Gilbert RO. 2006. Definingpostpartum uterine disease in cattle. Theriogenology 65,1516–1530.

Slebodzinski AB, Lipczak W, Brzezinskaslebodzinska E.1995. Peroral administration of triiodothyronine (T-3)affects absorption of immunolactoglobulins in calves.Reproduction Nutrition Development 35, 387–393.

Stott GH, Marx DB, Menefee BE, Nightengale GT. 1979.Colostral immunoglobulin transfer in calves. 1. Period ofabsorption. Journal of Dairy Science 62, 1632–1638.

Suttle NF. 2010. The Mineral Nutrition of Livestock. CABI, Wall-ingford, CT.

Todini L. 2007. Thyroid hormones in small ruminants: effectsof endogenous environmental and nutritional factors.Animal 1, 997–1008.

Vanhoe H, Vanallemeersch F, Versieck J, Dams R. 1993.Effect of solvent type on the determination of total iodinein milk powder and human serum by inductively-coupledplasma-mass spectrometry. The Analyst 118, 1015–1019.

Voudouri AE, Chadio SE, Menegatos JG, Zervas GP, Nicol F,Arthur JR. 2003. Selenoenzyme activities in selenium-and iodine-deficient sheep. Biological Trace ElementResearch 94, 213–224.

Wichtel JJ, Thompson KG, Craigie AL, Williamson NB. 1996.Effects of selenium and iodine supplementation on thegrowth rate, mohair production, and thyroid status ofAngora goat kids. New Zealand Journal of AgriculturalResearch 39, 111–115.

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Effect of iodine, selenium and cobalt rumen boluses given to dry dairy cows on the immunoglobulin and thyroid hormone status of calves