Induction of Parturition in the Cow usingCloprostenol and Dexamethasone in Combination

FRED J. LEWING, J. PROULX AND REUBEN J. MAPLETOFT

Department of Herd Medicine and Theriogenology, Western College ofVeterinary Medicine, University of Saskatchewan, Saskatoon, SaskatchewanS7N 0 WO (Lewing, Mapletoft) and Agriculture Canada, Research Branch,Experimental Farm, Kapuskasing, Ontario PSN 2X9 (Proulx)

ABSTRACT

Two experiments were designed to testthe hypothesis that induction of partu-rition in the cow would be more pre-dictable with the simultaneous use of acombination of cloprostenol and dex-amethasone than with either hormoneused alone.

In experiment I all 19 beef cowstreated with 500 jug cloprostenol and25 mg dexamethasone in combinationcalved within 72 hours whereas dexa-methasone (n = 19) or cloprostenol(n = 16) treatments alone each resultedin two induction failures. In thosecows successfully induced, the meaninterval from treatment to birth was34.6 ± 1.4 hours for the cloprostenolplus dexamethasone group, 43.3 ± 2.4hours for the dexamethasone groupand 44.9 ± 2.1 hours for the clopros-tenol group. Control cows (n = 15) didnot calve during the first 72 hours aftertreatment with saline. The incidence ofretained placenta ranged from 19 to53% in induced groups whereas pla-centae were not retained by cows in thecontrol group.

In experiment II all 30 beef cows inthe cloprostenol plus dexamethasonegroup calved within the 72 hour limit,with a mean interval of 39.1 ± 1.0hours. Twenty-six of 31 cows calvedwithin 72 hours with a mean interval of51.9 ± 3.4 hours after a single injectionof cloprostenol and 29 of 33 cowscalved within 72 hours with a meaninterval of 52.6 ± 3.3 hours after twoinjections of cloprostenol, 12 hoursapart. Five of 34 control cows calvedwithin 72 hours of time of treatment.The incidence of retained placenta wasagain high in induced cows. Results

indicate that the simultaneous admin-istration of cloprostenol and dexa-methasone does constitute a safe, reli-able and effective method of inducingparturition in the cow.

Key words: Cloprostenol, dexametha-sone, beef cows, induction ofparturition.

R G S U M t

Induction du velage, par l'injectionsimultanee de cloprostenol et de de-xamethasone 'a des vaches parturientesLes auteurs ont concu deux experien-ces destinees 'a verifier l'hypotheseselon laquelle l'injection simultanee decloprostenol et de dexamethasone 'ades vaches parturientes permettrait depredire plus exactement le moment duvelage, que l'injection de seulementl'une ou l'autre de ces hormones.Dans la premiere experience, les 19

vaches 'a boeuf qui requrent simultane-ment 500 ug de cloprostenol et 25 mgde dexamethasone velerent dans les 72heures ulterieures a l'intervention,tandis qu'on enregistra deux echeschez les 19 autres qui ne requrent quede la dexamethasone, tout commechez les 16 auxquelles on n'injecta quedu cloprostenol. Lorsque l'interven-tion s'avera fructueuse, l'intervallemoyen entre l'injection et le velageatteignit 34,6 ± 1,4 heures, chez lesvaches qui avaient requ les deux hor-mones, mais 43,3 ± 2,4 heures, chezcelles qui n'avaient requ que de la dexa-methasone, et 44,9 + 2,1 heures, chezcelles qui n'avaient recu que du clo-prostenol. Quant aux 15 vachestemoins, elles ne velerent pas dans les72 heures ulterieures a l'injection de

saline. La retention placentaire affectade 19% 'a 53% des vaches experimen-tales, mais aucune des temoins.Dans la deuxieme experience, les 30

vaches La boeuf qui requrent simultane-ment les deux hormones experimen-tales velerent dans les 72 heuresulterieures a l'injection, avec un inter-valle moyen de 29,1 ± 1,0 heures. Des31 vaches qui requrent une seule injec-tion de cloprostenol, 26 velerent dansles 72 heures ulterieures 'a l'interven-tion; l'intervalle moyen s'etablit La51,9 ± 3,4 heures. Des 33 vaches quirequrent deux injections de cloproste-nol, La 12 heures d'intervalle, 29velerent dans les 72 heures ulterieuresa ces injections, avec un intervallemoyen de 52,6 ± 3,3 heures. Cinq des34 temoins velerent dans les 72 heuresulterieures La l'injection de saline. Toutcomme dans la premiere experience,plusieurs vaches experimentales souf-frirent de retention placentaire.

Les resultats de ces experiencesindiquent que l'administration simul-tanee de cloprostenol et de dexametha-sone constitue un moyen sutr, fiable etefficace de provoquer le velage.

Mots cles: cloprostenol, dexametha-sone, vaches La boeuf, induction duvelage.

I N T R O D U C T O NIn the spontaneously calving cow

parturition is initiated by rising fetalplasma cortisol levels (1,2,3,4). Cor-tisol appears to gradually reduce ute-roplacental synthesis of progesterone(5,6) and increases estrogen produc-tion in the cotelydon (2,4,7), which inturn appears to initiate the production

Reprint requests to Dr. R.J. Mapletoft.

Can' Vet J 1985; 26: 317-322. 317

and release of cotelydonary prosta-glandin (4,8). Complete luteolysisoccurs in response to the prostaglan-din release and as progesterone sup-port for the pregnancy is lost, parturi-tion ensues (4).Hormones used to induce parturi-

tion initiate endocrine events normallytriggered by fetal cortisol. The induc-tion of parturition has been studied incattle after treatment with estrogens(9), corticosteroids (10,1 1,12), combi-nations of corticosteroids and estro-gens (13,14,15,16,17), prostaglandinalone (18,19,20), combinations ofprostaglandin and estrogens (18) andprostaglandins following corticoster-oid treatment (19,21). However,regardless of the method, significantadvances with respect to the efficacy ofinduction or reduction in the incidenceof retained placenta have not beenreported (15). Induction efficacy hasbeen reported to range from 80-90%and the interval from injection to par-turition has varied from 24 to 72 h,with a mean of approximately 48 h. Amore efficacious and predictabletreatment for the induction of parturi-tion would be useful.

In this laboratory we have pre-viously shown that cloprostenol (ananalogue of prostaglandin (PG) F)and dexamethasone in combinationwould induce abortion in feedlot heif-ers, regardless of the stage of gestation(22). Therefore, it has hypothesizedthat the simultaneous use of this drugcombination may be more predictablein inducing parturition than eitherhormone alone. The purpose of exper-iment I was to test this hypothesis andexperiment II was designed to confirmthe results of experiment I in a fieldtrial and to determine whether twoinjections of cloprostenol 12 h apartwould improve its efficacy in inducingparturition.

MATERIALS AND METHODS

Experiment IEighty healthy pluriparous cross-

bred Simmental recipient cows carry-ing fullblood Simmental calves wereused in this experiment. Cows were feda ration of cereal silage and were con-fined for continuous observation fromtreatment until calving occurred.On day 280 of gestation cows were

randomly placed by replicate into oneof four treatment groups. Cows in

group I received 500 Mg (2 mL) clopros-tenol (Estrumate - ICI Pharma, Mis-sissauga, Ontario) concurrently with25 mg (12.5 mL) dexamethasone(Dexamone "2" -- Rogar/STB, BTIProducts Inc., London, Ontario) attwo separate injection sites (CP +DEX). Cows in group II received 25mg dexamethasone (DEX), cows ingroup III received 500 Mig cloprostenol(CP) and cows in group IV received14.5 mL saline (CONTROL). Controlcows not calving by 290 days of gesta-tion were injected with the CP + DEXcombination at that time (CONTROL-I). All drugs were given by intramuscu-lar injection at 1800 h. Cows calvingless than 24 h after treatment were con-sidered to have been calving normallyand with the exception of CONTROLcows, were removed from the experi-ment. Cows not calving by 72 h aftertreatment were considered inductionfailures and were treated with the otherhormone, e.g. DEX failures wereretreated with CP.A blood sample was taken each

morning and evening from the time oftreatment (day 280) until calvingoccurred, at which time an additionalblood sample was taken. A final bloodsample was taken 48 h after calving.Serum was harvested and stored at-20° C until progesterone was analyzedby a validated procedure (23). Serumprogesterone levels between groupswere compared at times relative to thetime of calving.

End-points recorded were: induc-tion success rate, gestation length andtime intervals from injection toappearance of the chorioallantois, andto completion of delivery. In addition,calving ease, calf vigor, birthweight,mothering ability and incidence ofretained placenta were recorded.

Calving was classified as unassistedor assisted and if assisted whetherrepositioning, traction (slight, moder-ate, or forced) or cesarean section wasrequired. Dilation of cervix and birthcanal was also evaluated.

Calf vigor was recorded as normal ifthe calf was able to stand and nursewithin one hour of birth. All calvesreceived a minimum of I L of colos-trum by way of a stomach tube withinI h of birth.Normal mothering ability was based

on the dam's initial acceptance of hercalf and adequate milk production at

calving. Udder development wasrecorded at time of injection, at partu-rition and 48 h after calving and sub-jectively classified as "slack", "filled"or "tight".The incidence of retained placenta

was recorded 48 h after parturition.Cows were not routinely treated forretained placenta. If a cow with aretained placenta developed a fever,depression or anorexia, she wastreated intrauterine with 5 g oxyte-tracycline (Liquamycin - L.P.,Rogar/STB, Division of BTI, Lon-don, Ontario).

Experiment IIIn a field trial, 147 cross-bred

Hereford-Shorthorn cows on a grasssilage ration and in very good bodycondition were placed at random, bysire of calf and by replicate, into one offour treatment groups on day 276 ± Iof gestation. Cows in group I (CON-TROL) were not treated, while cows ingroup II received a single injection of500 ,g cloprostenol (CP) and cows ingroup III received two injections of500 Mug cloprostenol 12 h apart (CP-CP). Cows in group IV received 500 Mgcloprostenol and 25 mg dexametha-sone at the same time (CP + DEX).Treatments were given by intramuscu-lar injection at 1600 h and the secondCP treatment in group III was giventhe next morning at 0400 h. Cows wereobserved for parturition and assisted ifnecessary. Cows calving before 24 hwere considered to be calving nor-mally and with the exception of CON-TROL cows, were removed from theexperiment. Cows not calving by 72 hafter treatment were considered induc-tion failures.The following observations were

made: time interval from treatment tocompletion of delivery, calving ease,calf vigor, calf weight 48 h after calv-ing, milk production and incidence ofretained placenta. Cows were exam-ined 48 h postpartum for retained fetalmembranes and were treated with sys-temic antibiotics, only when depres-sion or anorexia occurred.

Statistical AnalysisInduction failure cows in experi-

ment I and those requiring cesareansection in both experiments were notconsidered in analysis of "time data".The incidence of retained placenta was

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based on those which were successfullyinduced and not requiring a cesareansection in both experiments. Quantita-tive data were analyzed by one-wayanalysis of variance and means werecompared by the Student-Newman-Keuls test. A chi-square test was usedto compare differences among thegroups in induction success rate, calv-ing ease, calf vigor, calf acceptance,milk production and incidence ofretained placenta.

RESULTS

Experiment IIn the CP + DEX group all cows

calved within the 72 h limit after injec-tion, whereas the DEX or CP treat-ments each resulted in two inductionfailures (I 1% and 13% induction fail-ures, respectively; Table I). Theseinduction failures calved within 48 hafter treatment with the "other"hormone.Nine cows in group IV (CONTROL-

I) were induced with the combinationof cloprostenol and dexamethasone at290 days of gestation. They calvedwithin 48 h after the combination wasinjected with a mean interval of29.4 ± 2.3 h. This was approximately 5h earlier than cows induced with thesame combination at 280 days ofgestation.The time intervals from treatment to

completion of delivery and for gesta-tion length, were not significantly dif-ferent among induction groups but allwere significantly less than for theCONTROL group (p < 0.05). Whenonly induction groups were compared(Groups I, I1 and III) the CP + DEXgroup had a significantly shorterinterval from treatment to calvingthan either the CP or the DEX group(p < 0.05).The range during which calving

occurred following induction treat-ment tended to be less for the CP +DEX group (2542 h) than for theDEX group (29-65 h) or the CP group(33-57 h). In addition, 100% of thecows in the CP + DEX group calvedwithin 48 h after induction whereasonly 63% of the DEX group and 44%of the CP had calved by this time. Theinterval from appearance of the chor-ioallantois until completion of deliv-ery was significantly longer (p < 0.05)for the CP group than for all othergroups (Table I).

TABLE IINDUCTION OF PARTURIT'ION IN COWS WIl'H CLOPROSTENOL OR DEXAMETHASONE

ALONE OR IN COMBINATION (EXPERIMENT 1)

Interval (h)Treatment Success Gestation Chorion to Treatment toGroup Rate a nb Length Birth Birth

CP+ DEX 19/19 15 281.4 ±0.e 3.2 ±0.3c 34.6± 1.4eDEX 17/19 16 281.8 ± 0.l 2.4 ± 0.6 43.3 ± 2.4eCP 14/16 12 281.9 ± O.le 5.3 ± 0.8' 44.9 ± 2.leCONTROL 0/15Nc 6 286.4 ± 0.9' 2.6 ± 0.8e 153.6 ± 21.4'1d 9 291.2 ± 0.g 2.4 ± 0.4e 269.4 ± 2.3g

aNumbers calving within 72 hblnduction failures and cesarean sections removed (mean ± SEM)cControl cows calving before 290 daysdControl cows not calving by 290 days were induced with CP + DEX in combinationefgMeans within columns with different superscripts are different (p < 0.05)

TABLE IICALF BIRTH WEIGHTS (MEAN ± SEM) AND CALVING EASE OF Cows INDUCED TO CALVE

AT 280 DAYS OF GESTATION (EXPERIMENT I)

Calving Ease

Treatment Birth weightGroup na (kg) Unassistedb Assistedc Cesareane

CP+ DEX 19 43.1 ±0.7 12 3 4DEX 17 42.9 ± 1.6 14 2 1CP 14 41.5± 1.5 10 2 2CONTROLN 6 45.2 1.8 6 0 0id 9 45.9 1.5 7 2 0

alnduction failures removedbUnassisted or slight manual traction by one personCManual traction by two or more personsdControl cows not calving by 290 days were induced with CP + DEX in combinationeSix cesareans were due to relative fetal oversize and one was a result of poor cervical dilation

TABLE IllCALF VIGOR, MOTHERING ABILITY AND INCIDENCE OF RETAINED PLACENTA IN Cows

INDUCED TO CALVE AT 280 DAYS OF GESTATION (EXPERIMENT I)

InadequateTreatment Weak Milk at Retained PlacentaaGroup n Calves Calving Number Percentage

CP+ DEX 19 1 3 8/15 53DEX 19 0 0 3/16 19CP 16 0 2 6/ 12 50CONTROLN 6 0 0 0/6 0I b 9 0 0 4/9 44

aInduction failures and cesarean sections removedbControl cows not calving by 290 days were induced with CP + DEX in combination

The calving process was consideredto be essentially normal and there wasno difference between groups as tobirth weight or the degree of assistancerequired (Table II). There were nomalpresentations and with the excep-tion of one cow in the CP group, dila-tion of cervix and birth canal was not a

problem. All assisted deliveries andcesareans were a result of a relative orabsolute oversized fetus. Calves werehealthy at birth and there were no calflosses within the first week after birth(Table III). The one weak calf wasborn outside and exposed to the ele-ments at a temperature of-30°C.

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All dams accepted their calves andmilk production was satisfactory.Although many cows had little evi-dence of udder filling prior to induc-tion only five did not have completeudder filling at calving, and all cowswere in full lactation within three daysafter calving. One cow in the CP +DEX group had a history of inade-quate milk production in previousyears.

Although the incidence of retainedplacentae approached 50% in inducedgroups differences between groupswere not significant (Table III). Fur-thermore, the incidence of retainedplacenta in cows induced with the CP +DEX combination at 280 days andthose induced at 290 days of gestationdid not differ (53% vs 44%, respec-tively). Only one cow required treat-ment for retained placenta. All cowshave since been re-used as recipientsfor embryo transfer without problems.Serum progesterone levels did not

differ between groups at the time oftreatment (overall mean of5.40 ng/ mL)or at any other time after treatmentuntil calving. However, there was a ten-dency for progesterone levels to behigher in the CP group (III) than inother groups in the last sample beforecalving. At the time of calving serumprogesterone levels were significantlyhigher (p < 0.05) for the CP group(1.31 ± 0.17 ng/mL) than for the CP +DEX group (0.81 ± 0.08 ng/ mL), theDEX group (0.64 ± 0.07 ng/ mL), theCONTROL-N group (0.75 ± 0.06ng/ mL) and the CONTROL-I group(0.68 ± 0.08 ng/ mL). Forty-eight hoursafter calving there were again no signif-icant differences between groups (over-all mean of 0.53 ng/ mL).

TABLE IVINDUCTION OF PARTURITION IN COWS WITH ONE INJECTION OF CLOPROSI-ENOL. Two INJECT-IONS OF

CLOPROSTENOL 12 HOURS APART OR ONE INJECTION OF CLOPROSTENOL IN COMBINATIONWIlTH DEXAMETHASONE (EXPERIMENT 11)

Treatment Induction Gestation TreatmentGroup Success Ratea nb Length (days) to birth (h)CONTROL 5/34 34 283.4 +0.7c 184.9± 15.9cCP 26/31 30 277.9 ± 0.2d 51.9 ± 3.4dCP-CP 29/33 33 278.2 ± 0.2d 52.6 ± 3.3dCP + DEX 30/30 30 277.6 ± o.Id 39.1 ± 1 odaNumbers calving within 72 h significantly less in control group (p < 0.01)bOne cesarean section in group CP removed (mean ± SEM)cd Means within columns with different superscripts are different (p < 0.05)

whereas 97% of cows receiving the CP+ DEX combination had calved.When only induced cows were com-

pared (Groups II,III,IV) cows treatedwith CP + DEX had a significantlyshorter interval from treatment tocompletion of delivery than groupsthat received only CP (p<0.05).Again, this interval tended to be lessvariable for the CP + DEX group thanfor the other treatment groups.

Although weights for control calveswere 4.2 kg heavier (p < 0.05) thanthat of induced groups (Table V), thisdid not result in greater calving diffi-culties. Dystocia scores, calf viabilityand onset of lactation were similar inall groups.The incidence of retained placenta

in all induced groups was high anddiffered significantly (p < 0.01) fromthat of the CONTROL group (TableV). Retained placentae did not causeany serious medical problems andcows have since been rebred.

D I S C U S S IO N

The results of experiment I were con-firmed in experiment II in that a com-bination of cloprostenol and dexa-

methasone was 100% effective in theinduction of parturition. Further-more, 98% of the cows receiving thiscombination calved within 48 h aftertreatment and the range of times dur-ing which calving occurred tended tobe less variable than in other groups.This has also been reported when aPGF analogue was given in two injec-tions, 24 h and 29 h after dexametha-sone treatment (24). This synergisticeffect of the combination may be aresult of the action of each hormoneon different sites.The sharp drop in progesterone that

occurs over the last 3648 h beforecalving has been attributed to the ris-ing concentrations of PGF (2,25).However, doubt remains as to thecause of the gradual progesteronedecline prior to this time (7,17,25). Asthe adrenals can probably be disre-garded as a source contributing toperipheral progesterone levels in thepregnant cow (7,26), the placenta oruterus may be considered a likelysource of the extra-ovarian progester-one. This hypothesis is supported byan earlier study in which higher pro-gesterone levels were shown to exist in

Experiment IIAll cows treated with the CP + DEX

combination calved within 72 h with amean interval of 39.1 ± 1.0 h (TableIV). The single cloprostenol treatment(CP) was only 84% effective and thedouble cloprostenol treatment (CP-CP) was 88% effective. There was nodifference in the interval from treat-ment to calving between treatmentgroups but all intervals were signifi-cantly shorter than that for the CON-TROL group (p < 0.05). Within 48 hafter induction treatment 48% of thecows receiving CP alone had calved

TABLE VCALF WEIGHT AND INCIDENCE OF RETAINED PLACENTA IN COWS INDUCED TO CALVE

AT 276 ± DAYS OF GESTATION (EXPERIMENT 11)

Calf Weight (kg) Retained PlacentabTreatment Group na mean ± SEM Number PercentageCONTROL 33 41.4 ± 0.9c 1/34 3CP 28 37.1 ± 10.d 15/25 60CP-CP 33 37.7 ± o.9d 16/29 55CP + DEX 29 36.8 ± o.9d 16/30 53aSome calves were not weighedblnduction failures and the cesarean in group CP removed; incidence significantly less in control group(g<O.01)c Means within columns with different superscripts are different (p < 0.05)

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the uterine vein than in thejugular veinof 32 cows at 210 days of gestation (6).Collectively, data indicate that aroundthe beginning of the last trimester ofgestation a uteroplacental source con-tributes to peripheral levels of proges-terone and that as pregnancy pro-gresses the uteroplacental source ofprogesterone gradually declines, theovarian source becoming more impor-tant, as is the case in early pregnancy.Therefore, it can be hypothesized thatnear term, corticosteroids act on theuteroplacental unit to terminate localprogesterone production and thatPGF acts by terminating the ovariansource of progesterone. Further, in thetwo CP failures in experiment I, serumprogesterone declined from a mean of8.78 ng/mL to a mean of 2.05 ng/ mLduring the following 72 h. However,progesterone levels did not drop below1.0 ng/ mL until after DEX treatment.Results were less obvious in the twoDEX failures in that serum progester-one levels did not decrease signifi-cantly until after treatment with CP.Regardless of the mechanism ofaction, an effective local and generaldecrease in progesterone wouldappear to be the basis for the highefficacy of the CP + DEX combina-tion.An observation was made that some

induced cows in experiment II tendedto take longer than normal from firstsigns of second stage labor to actualdelivery. However, specific groupswere not recorded. In experiment I,the interval from appearance or rup-ture of the chorioallantois to comple-tion of delivery was significantlylonger for the group that received onlycloprostenol than for all other groups(Table I). Others have reported thatsigns of preparation for calving wereless marked in the cows treated withanother PGF analogue when com-pared to controls or cows whichreceived dexamethasone alone (24).Although the physiological eventscausing this phenomenon are notknown, it may be explained by the sig-nificantly higher progesterone levelspresent at birth in the CP group. Wesuggest that although the ovariansource of progesterone was susceptibleto cloprostenol treatment, a muchlesser source (uteroplacental) was notand that this low level of progesteronetended to suppress uterine activity.

Combined results of both experi-ments indicate that the frequency ofplacental retention was not decreasedby the combination of cloprostenoland dexamethasone and was signifi-cantly higher with all methods ofinduction than in control groups.There was also a high percentage ofplacental retention whether cows weretreated with the combination of clo-prostenol and dexamethasone at 280days or ten days later at 290 days ofgestation. This has also been reportedwhen PGF or PGE was used at 287days to treat prolonged gestation (20).Further, there did not appear to be anyrelationship between progesteronelevels at calving and placental reten-tion. It is interesting that although pla-cental retention was not treated, sub-sequent illness or infertility did notoccur.

Collectively, these results demon-strate that induction of parturition canbe used as a managemental tool in cat-tle. Assuming that there is little circa-dian difference in response to induc-tion (27) and considering thepredictability of cloprostenol anddexamethasone in combination fromthis study, a very modest modificationof timing may result in most, if not all,calves being born within workinghours. Success is dependent on a highlevel of management as increasedlosses are possible if the procedure isimproperly utilized (28,29). However,results do indicate that the simultane-ous administration of cloprostenoland dexamethasone does constitute asafe, reliable and effective method ofinducing parturition in the cow.

ACKNOWLEDGMENTSThese studies were supported finan-cially by ICI Pharma, Mississauga,Ontario, Canada and the AlbertaAgricultural Research Trust Fund.The authors wish to acknowledge andthank P. Lewing, J. Booker, M.Braithwaite and Denis Lavoie for theirtechnical assistance and J. Deschnerfor her typing. Experiment I was con-ducted at Little Pipestone Ranch,Frenchmans Butte, Saskatchewan andExperiment II was conducted at theAgriculture Canada ExperimentalFarm, Kapuskasing, Ontario. Prelim-inary results of this work have beenpublished in the Proc of the 10th IntCongress of Anim Reprod and Al,

Urbana-Champaign, U.S.A., 1984and in the Compend Cont Ed, ProcSymp on Reprod Mgt in Food Ani-mals, Fall Conference, 1983.

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27. KORDTS E, JOCHLE W. Induced parturition indairy cattle: A comparison of a corticoid(flumethasone) and a prostaglandin(PGF2a) in different age groups. Therioge-nology 1975; 3: 171-178.

28. CARROLL EJ. Induction of parturition infarm animals. J Anim Sci 1974; 38 (Suppl.1): 1-9.

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BOOK REVIEW

Laboratory Animal Medicine. Editedby J.G. Fox, B.J. Cohen and F.M.Loew. Published by AcademicPress, Orlando, Florida. 1984. 723pages. Price US $60.00.

This hard cover book is recom-mended to students in veterinary med-icine, to laboratory animal specialistsand to researchers using laboratoryanimals in their research. In the firsttwo chapters, the authors review thehistory of laboratory animal medicine.They inform the reader on the individ-uals and organizations that have influ-enced the development of this specificfield of veterinary medicine. Theimpact of laws, regulations and poli-cies affecting the use of experimentalanimals is also discussed. In the nextchapters, we have access to pertinentinformation on the diseases and biol-ogy of a wide variety of laboratoryanimal species. Characteristics of each

species, their diseases, their particularneeds for environmental factors, cag-ing and nutrition are discussed. Thosespecies include rats, mice, rabbits, gui-nea pigs, hamsters and primates aswell as domestic, wild and exoticspecies.The book also deals with other

aspects of animal experimentation.Techniques such as drug administra-tion, collection of biological speci-mens, surgical procedures, anesthesiaand euthanasia are covered. Advan-tages and disadvantages of alternativeways to perform the same procedureare also given.A review of selected known or

potential zoonotic agents and of thedisease manifestations produced inhumans exposed to infected animals isincluded. A chapter also covers factorsthat complicate animal research. Thisspecific chapter reviews a number ofenvironmental and biological factors

categorized as physical, chemical andmicrobiological.

In the chapter concerning animalmodels in biochemical research, we areintroduced to selected laboratoryanimal diseases and to their humancounterparts. The editors also informthe reader on rodent and lagomorphehealth surveillance programs. Theypresent the principles of quality-assurance programs. Finally theystress the importance of developingresearch in laboratory and compara-tive medicine.

In conclusion, this book is presentlythe most complete publication availa-ble on laboratory animal medicine.The bibliography is quite extensiveand provides the reader with addi-tional sources of information. Wehighly recommend this book to allthose interested in laboratory animalmedicine.

Jn. -P. Descoteaux.

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