Author Institution: Department of Dairy Science, Ohio Agricultural Experiment Station, Wooste

Gilmore, L. O.

Laird, R.

Treece, J. M.

The Ohio Journal of Science

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32 CHEMISTRY SYMPOSIUM Vol. 59CHANGES IN BODY MEASUREMENTS OF HEIFERSAT FIRST PARTURITION1R. LAIRD*, L. O. GILMORE, AND J. M. TREECEDepartment of Dairy Science, Ohio Agricultural Experiment Station, WoosterIt is generally recognized that changes occur in some of the body measure-ments at parturition. Cattlemen are cognizant of the relaxation of the pelvicbones before parturition and the reduction in the circumference of chest andpaunch after parturition. Little seems to be known about other possible changesexcept the swelling of the udder which causes an increase in the stifle measurement.The changes in body measurements at parturition are of importance to thoseinterested in the developmental phases of cattle. Information of this naturemight be valuable for predicting certain details of show condition on an anticipateddate and for interpreting research data. However, it is likely that the changesjournal Article No. 55-55, The Ohio Agricultural Experiment Station.2Present Address: Animal Husbandry Department, West of Scotland Agricultural College,Auchincruive, Ayr, Scotland.THE OHIO JOURNAL OF SCIENCE 59(1): 32, January, 1959.No. 1 BODY MEASUREMENTS OF HEIFERS 33may be of greater interest from the standpoint of physiological behavior. Thepresent paper is concerned with a study of body measurements before and afterfirst parturition.EXPERIMENTAL PROCEDUREThe data used in this study were taken from a project concerning growthand development in cattle in which twins and triplets were the prime experimentalsubjects. A minimum of 18 body measurements were taken each week fromtime of acquisition of the cattle until at least one month after first parturitionand then once a month thereafter. As a result, there are no comparable datafor parturition subsequent to the first. A preliminary analysis of the data fromthe twins was undertaken and additional data on those measurements showingchanges were collected on other heifers, singly-born, from the Experiment Stationdairy herd to obtain more accurate estimates of these changes.The twin animals used in this study consisted of one pair of monozygoticGuernseys, one pair of monozygotic Shorthorn x Guernseys, two pairs of Holstein-Friesians, at least one pair of which was monozygotic, one pair of monozygoticBrown Swiss twins, one pair of dizygotic Jersey twins, one Red Poll and oneTABLE 1Model used in the analysis of varianceSource of Variation D.F. Composition of Mean SquareBetween periods (P) 1 <7VBetween animals (A) a-1 o-yInteraction between periods and animals (PxA) a-1 <7WA~'"3<rPABetween weeks within periods (W) 4 <ryyA-(-atr^rBetween weeks within periods x animals orerror (WA) 4 ( a - ! ) *W2AGuernsey for whose twins similar data either were not available or were suspectbecause of illness. The nontwin heifers consisted of 4 Jerseys and 3 Holstein-Friesians, giving a total of 21 animals. These heifers calved from Septemberthrough March of three different seasons at an average age of just over 2 years2 months. Of the 21 heifers, 18 calved at ages from 2 years to 2 years 3 monthswhile the other three calved at ages of 2 years 5 months, 2 years 8 months, and 2years 9 months.The data for the three weeks prior to and immediately following parturitionwere arbitrarily chosen for each animal. Because the measurements were takenon the same day each week, the last measurement before parturition fell 1 to 6days before the day of parturition. It was desired to isolate the following sourcesof variation; between periods (P), i.e., before and after parturition; betweenanimals (A); the interaction between periods and animals (PxA); between weekswithin periods (W); and weeks within periods times animals or error (WA). Periodsand weeks were regarded as fixed variables and animals as a random variable. Amethod presented by Schultz (1955) was employed to set up the model shown intable 1.In the tests of significance, the between weeks within periods (W) and the34 R. LAIRD, L. O. GILMORE, AND J. M. TREECE Vol. 59interaction between periods and animals (PxA) were tested against the error meansquare. On the other hand, the mean square between periods was comparedto PxA only. The degrees of freedom for this new error term was determined bythe method of Satterthwaite (1946). In the statistical model used (table 1) thedifferences between animals were not of interest since no importance was attachedto the magnitude of the measurements and therefore the statistical significance ofthe mean square between animals was not determined.An interaction between periods and animals would indicate a differentialresponse to the influence of parturition. To determine whether the interactionwas caused by some factor peculiar to breed structure, an additional analysiswas made. The measurements for 21 cattle were divided into 5 breed groupscomprising (a) 3 Guernseys, (b) 2 Beef Shorthorn x Guernseys and 1 Red Poll,(c) 2 Brown Swiss, (d) 6 Jerseys and (e) 7 Holstein-Friesians. The interactionbetween periods and animals was subdivided into that between periods and breedgroups and that between periods and cattle within breed groups.TABLE 2Results of analysis of variance for body measurements of heiferstaken before and after first calvingPoll to muzzleHead widthEye to mandible'1Circum. of muzzleMandible to jawcCircum. of neckHeart girthWithers heightWidth of shouldersDepth of chestLength of bodyCircum. of metacarpusCircum. of metatarsusStifle to stifle (tape)Width of hooksWidth of thurlsWidth of pinsHooks to pinsBody weightNo. ofAnimals14141114142121212121212121212114212120Change at calving(Before—After)Mean (cm) {+0.05-0.02-0.05+0.03+0.01-1 .81-3.84+0.92-1 .23-0.91-0.03-0.21-0.24+0.30-0.30-0.05-0.26-0.14-109.0 (lb)significance11n.s.n.s.n.s.n.s.n.s.***************n.s.#****n.s.***n.s.n.s.n.s.Interaction(PxA)Significance51n.s.n.s.n.s.n.s.n.s.n.s.****n.s.*****n.s.*n.s.n.s.n.s.***Weeks withinperiodsSignificance"n.s.n.s.n.s.n.s.n.s.n.s.n.s.n.s.n.s.**n.s.n.s.n.s.**n.s.n.s.n.s.n.s.***«n.s.—not significant- * = P<0.05, ** = P<0.01, *** = P<0.001.bFrom top of eye socket to angle of mandible.cFrom angle of mandible to anterior extremity.RESULTS AND DISCUSSIONThe head measurements were unaffected by parturition as indicated in table 2.The circumference of neck declined by an average of 1.81 cm and may be attributedto the dehydration of the body tissues incident to parturition and subsequent lac-tation. In as much as both circumference of neck and stifle to stifle distanceare measurements of muscle developments this drain on the body may affect thestifle to stifle measurement also but be masked by the complicating effect of theudder swelling. This swelling of the udder becomes apparent in the stifle tostifle measurement one or two weeks before parturition and for a week or soafterwards. As anticipated, this measurement reached a maximum soon afterNo. 1 BODY MEASUREMENTS OF HEIFERS 35parturition and then declined. Because of this curvilinearity statistically sig-nificant differences were recorded between weeks within periods before and afterparturition and the quadratic regression of measurements on weeks was significantat the 0.05 level of probability. The mean value before parturition was notsignificantly different from that after parturition.A series of weekly changes similar to those of the stifle to stifle measurement,though not statistically significant, was also observed in the case of length ofbody (from the anteriormost cervical vertebra between the scapulae to the lefttuber ischium or pin bone). In fact, most of the variation between weeks wasaccounted for by the quadratic regression of measurements on weeks. Thismight be associated with the relaxation of the pelvic bones at parturition sincethe left tuber ischium was a reference point. The length of body, however,showed no consistent change with parturition but the animals did exhibit highlysignificant differential responses. These differences might be apparent ratherthan real due both to a possible sagging of the back and to the difficulty withwhich the anterior reference point could be palpated.The leg circumferences, both fore and rear, were less after parturition thanbefore, the fore leg by 0.21 cm and the rear leg by 0.24 cm. This ma}^  be due todehydration of the soft tissue or to improved lymphatic return similar to thatobserved after parturition in women. These leg measurements seemed to reachminimum values at 4 to 7 weeks after parturition.Of the pelvic measurements, only the width between external points of tubercoxae (hooks) showed statistically significant sources of variation. This widthdeclined by 0.30 cm at parturition but there was also a significant differentialresponse which was small in comparison with the change at calving. Thedecline might be attributed to a return to normal after relaxation in preparationfor parturition. Although the width of pins showed a decline it just failed toreach statistical significance (P< 0.10). There was some evidence, however,that the minimum value after parturition was not reached until about one monthpostpartum and it is possible that significant differences might have been obtainedif data for 4 or 5 weeks postpartum had been analyzed. The width of thurls andlength from hooks to pins (length of pelvis or rump) were unaffected by parturition.In the shoulder region there were highly significant postpartum declines inheart girth, width of shoulders (the straight-line distance between the shoulderpoints measured by large calipers) and depth of chest. These declines wereprobably due to the physical effect of the weight of the calf. Similarly, theincrease in the height at withers may be attributable to the removal of the calfand placental membranes whose combined weight would seem to depress theheight at withers before parturition. In the case of width of shoulders, heartgirth and height at withers, significant differential responses were recorded butthe between-weeks-within-periods variation was significant only in the depth ofchest measurement due to a rise of 0.50 cm in the week prior to parturition and toa marked fall of 0.50 cm in the third week thereafter. The quadratic regressionof chest depth on weeks approached statistical significance. There changes maybe due to relaxation in preparation for parturition and to tension of ligmanetsthereafter, respectively.For purposes of comparison body weights at each of the three weeks beforeand after parturition were analyzed also. The mean decline in weight was foundto be 109.0 lb. The interaction between animals and periods was found to behighly significant indicating that the weight loss varied appreciably from animalto animal, an average increase of 16 pounds in weight was recorded in the secondweek prior to parturition and in the postpartum period the weight declined pre-sumably due to the drain of lactation on the body reserves. These changesresulted in a statistically significant between-weeks-within-periods mean square.After adjusting for the change at parturition, the quadratic regression of weightR. LAIRD, L. O. GILMORE, AND J. M. TREECE Vol. 59on weeks was significant (P< 0.05), due to a gradual increase in weight untilparturition and a gradual decline afterward.For those measures which showed statistically significant sources of variationthe original data were converted into logarithms and analyzed with the results asindicated in table 3. The only changes compared with the original analysisconcerned the interaction between animals and periods. That of the circum-ference of the rear leg (metatarsus) was now significant only at the 5 percent levelof probability, while that of width of shoulders was not statistically significant.The interaction in the case of the stifle to stifle measurement became statisticallysignificant at the 5 percent level of probability. It would seem, therefore, thatthe interaction between animals and periods was, in general, not caused by acorrelation between the magnitude of the changes in the measures of the indi-vidual animals and the magnitude of the measures themselves.TABLE 3Results of analysis of variance of the logarithms of the body measurements of heiferstaken before and after first parturitionCircum. of neckHeart girthWithers heightWidth of shouldersDepth of chestLength of bodyCircum. of metacarpusCircum. of metatarsusStifle to stifle (tape)Width of tuber coxaehooksWidth at tuber coxae pinsWeightNo. ofanimals212121212121212121212120(as a % ofmagnitudebeforeparturition)-2.18-2.12+0.77-2 .95-1.44-0.02-1.24-1.24+0.22-0 .63-0.85-10.45Significance"***************n.s.****n.s.***n.s.***Interaction(PxA)Significancen.s.***n.s.n.s.******n.s.***Weeks withinperiodsSignificancen.s.n.s.n.s.n.s.**n.s.n.s.n.s.*#n.s.n.s.***aSee footnote table 2.Since the difference of two logarithms represents the division of one naturalnumber by another, the difference of the means before and after parturition becamethe ratio of their measures after and before parturition when converted to antilo-garithms. By subtracting one from this ratio and multiplying by 100, the resultwas the change at parturition expressed as a percentage of the measurementbefore parturition (table 3).The circumferences of the legs and the depth of chest show percentage declinesof 1.24 to 1.44 percent while heart girth and circumference of neck declined byabout 2.1 percent. Width of shoulders showed the highest percentage decline(2.95%) of the body measurements whereas width of hooks showed the least(0.63%). Height at withers increased by 0.77 percent. As expected, bodyweight showed the largest decline of all, viz., 10.45 percent.With regard to the interaction between periods and animals, it was only inthe case of the stifle to stifle measurements that the interaction between periodsand breed groups was significantly greater than that between periods and animalswithin breed groups. This significant interaction was largely attributable to mostof the Jerseys showing a decline after parturition, the Holstein-Friesians showingno change and the other three groups showing increases. To what this differential30No. 1 BODY MEASUREMENTS OF HEIFERS 37response was due could not be ascertained. From these results it can be con-cluded that, with this one exception, the interaction between periods and animalswas not a breed difference but was due to individual differences between animalsirrespective of breed.These changes seemed to be largely independent of the inheritance of theindividual. This is partly borne out by the absence of breed differences as indi-cated above. However, to test this in another way the interaction betweenperiods and animals was divided into the interaction between periods and animalswithin twin-pairs and the residual interaction (i.e., the interaction of periodswith twin-paired and single-born animals). If there are changes attributable toinheritance, then the differences of the changes within twin-pairs should be lessthan the differences of the changes between twin-pairs and singly-born animals.In only one instance was this so. For heart girth, the interaction within twin-pairs was significantly less (P< 0.05) than the residual interaction and in onlytwo other cases did it approach statistical significance (P< 0.10). These werestifle to stifle and width of shoulders. This is interpreted as indicating thatmembers of a twin pair at parturition tend to have declines in heart girth, andpossibly stifle to stifle and width of shoulders, of a closer magnitude than onewould expect from pairs of animals taken at random. With these possible excep-tions it would appear that the inheritance of the animal plays a negligible role ininfluencing these changes and so these results are applicable to cattle in general.These results may serve as an indication of the type of change likely to occur atlater parturitions although the magnitude of these changes may be different.In the literature the only paper that could be found to give any details regard-ing changes in body measurements at parturition was that of Crichton and Aitken(1954). Their paper dealt with comparisons of monozygotic twins on high andlow planes of nutrition during rearing through first lactation. As in the presentstudy, they found declines in heart girth at first parturition with the possibleexception of low plane animals. With regard to width of hooks (hips) figures 2and 3 in their paper showed little or no change. Height at withers of 3 out of 4groups showed a decline and only one group (the low-low group) showed an in-crease with parturition. With the exception of the latter group, these results arein conflict with those of the present study. Crichton and Aitken suggested thatthe temporary reduction in the height at withers of the high plane animals mightbe due not to differences in bone development but to drawing on muscle or fatdeposited over the shoulders. If this were so, it might mean that the naimalsin the present study were comparable to the low plane animals. However, theanimals in the present study were raised on a normal to above normal plane ofnutrition and so the plane of nutrition would seem not to be the cause of thesimilarity. It must be appreciated that the data of Crichton and Aitken areless reliable than those of the present study since they are based on averages of2 or 4 animals.SUMMARYThe changes in body measurements of heifers at first parturition have beenstudied. The magnitude of the changes was calculated from the difference of themeans before and after parturition and the analysis of variance technique wasemployed to test the statistical significance of these changes.Height at withers showed a significant increase of 0.92 cm (or 0.77%) afterparturition. Measurements showing significant declines were: circumference offore leg (0.21 cm or 1.27%), circumference of rear leg (0.24 cm or 1.24%), circum-ference of neck (1.81 cm or 2.18%), heart girth (3.84 cm or 2.12%), width ofshoulders (1.23 cm or 2.95%), depth of chest (0.91 cm or 1.44%), width of hooks(0.30 cm or 0.63%), and body weight (109.0 lb or 10.45%). The other 10measures showed no statistically significant changes.38 R. LAIRD, L. O. GILMORE, AND J. M. TREECE Vol. 59Possible explanations of these changes are discussed. Individual variationswere encountered but these were independent of the inheritance of the individualas heredity was found to play a very minor role in influencing these changes.ACKNOWLEDGMENTSWe are very grateful to Dr. C. R. Weaver of the Entomology Department,Ohio Agricultural Experiment Station, for advice concerning the statistical analysesof these data. We also wish to record our thanks to Ross L. Johnson and WilliamKerr for assisting in measuring of the heifers.REFERENCESCrichton, J. A. and J. N. Aitken. 1954. The economical rearing of dairy heifers. Proc. Nutri-tion Soc. 13: 10-16.Satterthwaite, F. E. 1946. An approximate distribution of estimates of variance components.Biometrics 2: 110-114.Schultz, E. F., Jr. 1955. Rules of thumb for determining expectations of mean squares inanalysis of variance. Biometrics 11: 123-148.

Changes in Body Measurements of Heifers at First Parturition

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Changes in Body Measurements of Heifers at First Parturition

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