Biomedical subjects

W D Hohenboken

Publications and source records attributed to W D Hohenboken.

At least 37 records · Page 2Linked to original sources

PubMed1987

Heterogeneity of sperm nuclear chromatin structure and its relationship to bull fertility.

The relationship between sperm nuclear chromatin structure and fertility was evaluated in two groups of Holstein bulls: Group 1, 49 mature bulls, and Group 2, 18 young bulls. Fertility ratings had been estimated for Group 1 and nonreturn rates were known for Group 2. Semen samples were measured by the sperm chromatin structure assay (SCSA): sperm were treated to induce partial in situ DNA denaturation, stained with acridine orange, and evaluated by flow cytometry. Acridine orange intercalated into double-stranded DNA emits green fluorescence upon excitation with 488 nm light, and red fluorescence when associated with single-stranded DNA. An index of DNA denaturation per cell is provided by alpha-t [alpha t = red/(red + green) fluorescence]. The standard deviation (SD alpha t), coefficient of variation (CV alpha t) and proportion of cells outside the main population (COMP alpha t) of the alpha t distribution quantify the extent of denaturation for a sample. Intraclass correlations of the alpha t values were high (greater than or equal to 0.70), based on four collections obtained over several years from Group 1 bulls. Negative correlations were obtained between fertility ratings and both SD alpha t (-0.58, p less than 0.01) and COMP alpha t (-0.40, p less than 0.01) in Group 1, and between nonreturn rates and both SD alpha t (-0.65, p less than 0.01) and COMP alpha t (-0.53, p less than 0.05) in Group 2. These data suggest that the SCSA will be of value for identification of low fertility sires and poor quality semen samples.

Aging↗

PubMed1987

Inheritance and interaction of immune traits in beef calves.

Three sets of blood samples were obtained from beef calves of two experimental populations and assayed for various immunological measurements. The first set of samples was taken between 24 and 48 h after birth and quantified for IgG1 concentration. A second set was taken immediately prior to vaccination for infectious bovine rhinotracheitis virus (IBRV; at an average age of 164 d) and a third set taken 60 d post-vaccination. These later samples were quantified for antibodies specific to IBRV. Level of complement C3 was also quantified in the samples taken immediately prior to vaccination. Three hundred sixty-seven calves were from four Hereford lines; three lines were previously selected for growth traits and the fourth was a randomly selected control line. There were no consistent differences in immune traits among these lines. The second group of 165 animals were Angus, Hereford and Red Poll calves. While Angus calves had a higher mean IgG1 concentration at 24 to 48 h of age than Hereford or Red Poll calves, no differences among breeds were found for the other immune traits measured. Calves from older dams (greater than 3 yr old) tended to have higher mean IgG1 concentrations, pre-vaccination IBRV antibody titers and complement C3 levels than calves from 2- and 3-yr-old cows. However, these calves had lower 60-d post-vaccination IBRV titers than calves from the younger cows (P less than .05). As pre-vaccination IBRV antibody titer increased, post-vaccination IBRV antibody titer decreased (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Inheritance of active and acquired immunity traits in sheep.

Six hundred sixteen ewes of six strains were inoculated twice with ovalbumin in Freunds' incomplete adjuvant. To quantify the humoral immune response to the foreign antigen, blood samples were collected from all ewes 1 wk post-second injection. Blood samples were also collected between 4 and 40 h of age from their 709 lambs, to examine genetic differences in ability of lambs to acquire maternal anti-ovalbumin antibodies. Titers of anti-ovalbumin antibodies were determined using kinetic enzyme-linked immunosorbent assay (ELISA) techniques. Strain did not affect ewe immune response, but sire within strain was highly significant. In pregnant ewes, anti-ovalbumin antibody titers in 12- and 30-mo-old ewes were higher than those in 21-mo-old ewes. Number of lambs in utero did not significantly affect ewe immune response. Heritabilities of anti-ovalbumin titer from a paternal half-sib analysis were .27 +/- .17 for all ewes and .57 +/- .25 for only the pregnant ewes. The effect of strain of lamb on lamb anti-ovalbumin titer approached significance, and sire within strain was highly significant. Lamb anti-ovalbumin antibody concentration increased as time from birth to blood sampling increased to 18 h but declined thereafter. The size of the litter in which a lamb was born had a highly significant effect on the lamb's acquired immunity, with titer decreasing as litter size increased. The heritability estimate for lamb anti-ovalbumin antibody concentration from a paternal half-sib analysis was .38 +/- .11; it was .28 +/- .15 from the sire variance component of a full-sib analysis. When lamb titer was considered a maternal trait (lambs nested within their maternal grandsires within strains), the maternal grandsire variance component was negative. The average anti-ovalbumin antibody concentration of lambs that died between blood sample collection and 120 d of age was less than the average antibody concentration of lambs that survived (P less than .01).

Animals↗

PubMed1987

Production efficiency of crossbred ewes and that of their daughters and granddaughters.

Ewes of eight crossbred groups, born in 1973 and 1974, were maintained under two pasture management systems for five and four production years, respectively. After that experiment terminated, those crossbred ewes produced Polypay-sired lambs in 1979 and were then sold. Ewe lambs from those three-bred crosses were backcrossed to Polypay rams to produce lambs from 1980 to 1983. Five ancestor-descendant data sets (three involving dams and daughters and two involving granddams and granddaughters) were examined to study relationships between production efficiency of ancestor ewes and similar traits measured on their descendants. Ancestor cumulative prolificacy was positively but not significantly associated with cumulative prolificacy in the descendants. Regressions of descendant net revenue on ancestor net revenue were predominantly negative but generally were not significant. There was a tendency for prolific ancestors to produce costly but less profitable descendants. These results may be due to economic conditions (high feed costs and low lamb values) that persisted during the course of the experiment.

Animal Husbandry↗

PubMed1986

Sperm head morphology and nuclear chromatin structure evaluated by flow cytometry in a diallel cross in mice.

Genetic factors affecting spermatogenesis, sperm morphology, and chromatin structure in mice were estimated using a diallel cross of the inbred lines C3H/HeJ, C57BL/6J, DBA/2J, and BALB/cByJ. Flow cytometry of acridine orange stained cells was used to evaluate proportions of testicular tetraploid, diploid, and haploid cells and nuclear chromatin structure of sperm, measured by resistance of chromatin to in situ acid denaturation, and quantified by the ratio of double- to single-stranded DNA (alpha t). Percent morphologically abnormal sperm was scored by light microscopy. Heterosis, line, maternal, and reciprocal effects, and general and specific combining abilities were estimated for body and testis weights, testicular cell proportions, sperm alpha t values, and percent abnormal sperm. Heterosis was important for testis weight, alpha t values, and percent abnormal sperm. Inbreds varied in body and testicular weights, alpha t values, and percent abnormal sperm. Significant maternal effects were noted for several traits but could be due to sex-linked (X or Y) factors, since maternal and sex-linked effects were confounded. Although a high positive correlation existed between alpha t values and percent abnormal sperm, the proportion of sperm with altered chromatin structure, measured by FCM, was generally much lower than proportion of morphologically abnormal cells.

Animals↗

PubMed1984

Breed and sire effects on crossbred lamb production from Panama ewes and on spermatozoan midpiece length.

Three-hundred mature Panama-type range ewes were mated to Clun Forest, Dorset, Border Leicester, Polypay and Suffolk rams during the 1979 and 1980 breeding seasons. Sire breed and ram within breed effects on lamb growth, ewe reproduction, spermatozoan midpiece length (MPL) and midpiece length coefficient of variation (MPLCV) were examined. Associations among MPL and MPLCV and economically important traits also were assessed. Suffolk-sired lambs weighted .18, 2.0 and 1.5 kg more, at birth, weaning and post-weaning, respectively, than the average of all groups. Dorset-sired lambs had the lightest postweaning weight. Variation was greatest among Suffolk rams for average weaning and postweaning weights of their progeny. The Border Leicester breed had the least among ram variation for progeny weaning weight; while variation among Dorset rams was least for progeny postweaning weight. Fertility (ewes lambing/ewe exposed) and prolificacy (lambs born/ewe lambing) of the rams' mates were not influenced significantly by sire breed. Lamb mortality also was not influenced by breed of sire nor by rams within a breed. For variation in MPL, 26.4% was due to the breed effect (P less than or equal to .01) and 21.6% was attributable to ram variation within a breed (P less than or equal to .01). Clun Forest rams had the longest average MPL and greatest MPLCV, while Dorsets had the shortest MPL and smallest MPLCV. There were no important associations between either MPL or MPLCV and any of the economic traits.

Animals↗

PubMed1984

Inheritance of maternal immunoglobulin G1 concentration by the bovine neonate.

Serum samples were collected between 24 and 48 h of age from 408 Herefored calves of a Selection Experiment and from 200 Angus, Hereford and Red Poll calves of another experimental population (Germ Plasm Utilization Project). Concentrations of immunoglobulin G1 (IgG1) were determined by single radial immunodiffusion. Breed or selection line of calf and age of dam were the most important factors influencing IgG1 concentrations (P less than .01). In the Germ Plasm Utilization (GPU) herd, Angus calves were highest, Red Polls were intermediate and Herefords were lowest in serum concentrations. Calves from Hereford lines selected for weaning weight, yearling weight or an index based on yearling weight and muscling score were lower in IgG1 concentration than calves from the randomly selected control line. In both populations immunoglobulin levels in the calf increased as age of dam increased. In Selection Experiment Herefords, increased calving difficulty was associated with a decrease in calf IgG1 levels (P less than .05). Heritabilities of calf serum IgG1 concentration, estimated from paternal half-sib analysis on a within line or breed basis, were .03 +/- .09 and .13 +/- .19 in the two populations. In the Selection Experiment Herefords, when the component of variance for selection line was added both to the numerator and denominator of heritability, the revised estimate was .09 +/- .09. Heritabilities of maternal effects on IgG1 concentration were also estimated (by nesting calves within maternal grandsires) on a within line or breed basis. These heritabilities were .23 +/- .17 and -.07 +/- .27 for the Selection Experiment and GPU populations, respectively. In the Selection Experiment population, when the variance component for selection line was added to the numerator and denominator of maternal effects heritability, the estimate was .27 +/- . .17. Those calves that died had a lower mean IgG1 concentration than the population average (P less than .01).

Animals↗

PubMed1984

Genetic, environmental and interaction effects on lifetime production efficiency of crossbred ewes.

A total of 399 crossbred ewes born in 2 yr were maintained either on irrigated or dryland hill pastures. The ewes were sired by North Country Cheviot, Dorset, Finnsheep or Romney rams mated to Suffolk or Columbia-type ewes. The crossbred ewes were mated to Hampshire rams throughout the study and had the opportunity for either 4 or 5 yr of production. Annual feed cost was calculated based upon estimated annual metabolizable energy (ME) requirements for maintenance, ewe growth, pregnancy and lactation. Income from weaned feeder lambs and from orphan lambs sold shortly after birth, feed cost and net revenue were analyzed during each ewe's first production year, as well as for the entire period of the experiment. Crossbred group significantly affected income from lambs produced, feed cost and net revenue for the ewes' first production year. Crossbred group and crossbred group X management system interactions generally influenced lifetime income from lambs produced and from orphans sold, gross income, total cost and net revenue per ewe. Finnsheep X Suffolk ewes performed best on irrigated pastures but were below average for lifetime net revenue on hill pastures. Finnsheep X Columbia ewes performed best on hill pastures and, with Dorset X Suffolk and Dorset X Columbia ewes, were well above average for lifetime net revenue on irrigated pastures as well. Suffolk crossbreds consistently performed better on irrigated than on hill pastures. While most ewes with Columbia-type inheritance were more efficient on hill than on irrigated pastures, this result was not always consistent.

Animal Feed↗

PubMed1984

Phenotypic relationships among early life traits and lifetime ewe production efficiency.

In least-squares analyses of variance, 10 ewe lamb traits were used, singly and in various combinations, to predict lifetime production efficiency. Ewes belonged to eight crossbred groups and were raised on two management systems for either 4 or 5 yr of production. Lifetime production efficiency components were total feed and ewe ownership cost, gross income and net revenue. A ewe lamb's type of birth, actual and adjusted weaning weight (WWt and AWWt), postweaning weight (PWWt) and first year gross income (FGROS) were significantly phenotypically related to one or more components of lifetime production efficiency. While triplets were better than either of the other two birth types, single-born ewes were better than twin-born ewes for lifetime production efficiency. Any of the three ewe lamb weights (AWWt, WWt or PWWt) appeared to be an accurate estimator of lifetime production efficiency. The effect of first year productivity was largely a part-whole relationship with lifetime production because the regression coefficients of subsequent lifetime production efficiency (not including first year production) on first year productivity were near zero. Postweaning average daily gain, ewe age at first estrus and date of first lambing (at approximately 12 mo of age) did not have significant relationships with lifetime production efficiency. When type of birth, date of birth, weaning weight and first year gross income were analyzed simultaneously, weaning weight and FGROS had the greatest effect on lifetime production efficiency. When AWWt and type of birth were considered simultaneously, both had significant relationships with lifetime production efficiency.

Age Factors↗

PubMed1984

The effect of selection in retrospect on lifetime production efficiency in sheep.

Within 32 crossbred group-management system-birth year subgroups, "selection in retrospect" was practiced based upon several ewe lamb traits, singly or in combination, to assess what the effect of such selection would have been on ewe lifetime production efficiency. Ewes were from two birth years, eight crossbred groups and two management systems. Ewe's type of birth, date of birth, actual and adjusted weaning weight (WWt and AWWt), postweaning weight (PWWt) and first yr gross income (FGROS) were the ewe lamb traits involved in the single trait paper selection schemes. Only the ewe lamb weights (WWt, AWWt and PWWt) caused a significant increase in the production efficiency of selected populations over those of the corresponding unselected populations. When postweaning weight was used jointly with the ewe's type of birth in an independent culling level selection scheme, both the group composed of heavier multiple-born ewes and the group composed primarily of single-born ewes were more productive than the group composed of lighter weight multiple-born ewes. Backward selection of the elite ewes having the best production efficiency also showed that the heavier the ewe lamb, the more efficient she was expected to be. Examination of ewes surviving the entire duration of the experiment failed to identify any early life trait that predicted longevity. Furthermore, surviving ewes were equally variable in their early life traits to the populations at large. Longevity, however, was positively related to lifetime efficiency.

Animal Husbandry↗

PubMed1984

Effect of artificial photoperiod on eating behavior and other behavioral observations of dairy cows.

Twenty-eight cows were assigned randomly to a daily photoperiod of 18 h light and 6 h darkness or to continuous light and were observed 1 day each month from December 1981 to February 1982. Lighting regimen did not affect eating behavior or milk production. Overall means of total eating time, number of eating bouts, and average time eating per bout on the 3 observation days were 270 to 280 min, 10 to 12 times, and 24 to 27 min. Eating behavior and milk production were not significantly correlated. Eating patterns were similar in both groups and across observation days. Peaks of eating activity occurred before sunset, bracketing the evening milking and after the offering of fresh feed in the morning. Approximately 80% of total eating activity occurred between 0900 and 2100 h in both groups. Cows had a clear preference for entry into the right or left side of the milking parlor, and entry order was repeatable. Milking order and milk production were not correlated. In one group, location of free stalls did not influence utilization; but in the other group, centrally located stalls were utilized more than stalls at either end of the alley. About 40% of cows had individual free stall preferences.

Animals↗

PubMed1983

Estimation of repeatability, heritability and breed differences for lamb production.

Production records of crossbred ewes, including weight at mating (WTM), fertility (FRT), number of lambs born per ewe lambing (BRN), number of lambs weaned (WEN), litter weight in April (WTA) and litter weight at weaning (WTW), were analyzed for the estimation of breed differences, genotype x environment interactions and repeatability and heritability of ewe production. All ewes were from Suffolk- or Columbia-type dams. Breed of sire of ewe was Finnsheep, Dorset, North Country Cheviot or Romney, Suffolk-cross (SX) ewes were heavier at mating than Columbia-cross (CX) ewes. Cheviot-cross (NX) and Finnsheep-cross (FX) ewes were the most fertile on hill pastures, while Dorset-cross (DX) ewes were the most fertile on irrigated pastures. The FX ewes had larger litters at birth and at weaning. Columbia-cross ewes had larger litters than SX ewes on hill pastures, but the SX ewes had larger litters than CX ewes on irrigated pastures. Finnsheep-cross ewes on both types of pastures and DX ewes on irrigated pastures had heavier litter weights than NX or Romney-cross ewes at weaning. Repeatability estimates for WTM, FRT, BRN, WEN, WTA and WTW were .61, .15, .19, .08, .07 and .09, respectively. Heritabilities, from the sire-of-ewe component, were .40, .02, .12, .0, -.02 and -.05 for WTM, FRT, BRN, WEN, WTA and WTW, respectively.

Animals↗

PubMed1983

Doe reproduction and preweaning litter performance of straightbred and crossbred rabbits.

Reproductive characters (N = 430 matings) of four doe genetic groups and preweaning performance of litters (N = 280) were evaluated in a 15-mo study. Doe genetic groups were New Zealand White (NN) and Californian (CC) straightbreds and Californian X New Zealand White (CN) and New Zealand White X Californian (NC) crossbreds. Does and litters were provided either a commercial control or a 74% alfalfa pelleted diet. Sires of litters included NN, CC and Flemish Giant (FG) straightbred bucks. The linear and quadratic regression on age of dam affected (P less than .01) litter birth weight. The NN does were heavier than CC does at first breeding at 154 d and produced heavier litters at birth and weaning (all P less than .01). Percentage survival of kits from birth to weaning and doe and preweaning litter feed intake and efficiency were greater from NN than CC does (all P less than .01). Numbers born and reared/litter to weaning at 28 d were likewise greater for NN vs CC straightbred does. Heterosis estimated from comparing litters of reciprocal crossbred vs straightbred does was significant for number born, litter birth and weaning weights and doe and preweaning litter feed intake. Reciprocal crossbred differences were observed (P less than .05) for doe breeding weight, number born and weaned per litter, litter birth and weaning weights and doe and preweaning litter feed intake, favoring CN does reared by NN straightbred dams over NC does. Diet, in consistent favor of the 74% alfalfa diet, significantly affected all traits studied with the exception of doe longevity, doe fertility percentage, and doe and litter feed efficiency.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1983

Characterization of straightbred and crossbred rabbits for milk production and associative traits.

Two hundred twenty-five lactation and litter performance records from 82 does representing four genetic groups and two diets were analyzed to quantify breed, heterosis, reciprocal F1 cross and diet effects for milk production and associative traits. Doe genetic groups were New Zealand White (NN) and Californian (CC) straightbred and Californian X New Zealand White (CN) and New Zealand White X Californian (NC) reciprocal crossbreds. Pelleted diets fed to does and litters were either a commercial control or a 74% alfalfa diet. Three sire breeds of litters included NN, CC and Flemish Giant (FG) straightbreds. Doe genetic group and diet were important sources of variation (P less than .05) for all traits examined except for litter milk efficiency (litter gain/milk intake) and doe feed efficiency (milk yield/feed intake). The sire breed of litter effect did not influence (P greater than .05) lactational performance of does nor associative preweaning traits. Straightbred NN does were heavier at kindling, yielded more milk, reared a heavier litter by 21 d and were more efficient in converting feed into milk than were straightbred CC does (P less than .01). Significant heterosis was detected for milk production and for litter size and weight at 21 d. Reciprocal differences between crossbred doe groups were observed (P less than .05) for litter milk efficiency and doe feed intake. The 74% alfalfa diet was superior to the commercial control diet for effects on milk production and litter size and weight at 21 d, although doe feed intake was increased.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1983

Breed, heterotic and diet effects on postweaning litter growth and mortality in rabbits.

The effects of sire breed, dam genetic group and diet on postweaning litter growth and mortality were evaluated in 208 litters of rabbits. Sire breeds were New Zealand White (NN), California (CC) and Flemish Giant (FG). Dam genetic groups were NN and CC straightbred and California X New Zealand White (CN) and New Zealand White X Californian (NC) reciprocal crossbreds. Litters were fed either a commercial diet or a 74% alfalfa diet. Litter size and weight at 56 d and litter gain (the difference between 56- and 28-d litter weights) tended to be lower in NN- compared with CC-sired litters; while feed intake was significantly lower and mortality was higher in progeny of NN sires. Litter 56-d weight, litter gain and litter feed efficiency (gain/feed intake) were improved (P less than .05) in litters sired by FG vs NN or CC bucks. Direct heterosis (CN and NC compared with NN and CC litters) for litter size, growth and feed-related traits was generally low (less than 11% in absolute value), while moderate heterosis levels (-21 and -22%) were observed for diarrhea-related and total mortality. Differences between NN and CC straightbred dams for litter size and weight at 56 d and litter gain were small, but in favor of NN dams. Diarrhea-related and total mortality were higher (P less than .05) in litters reared by NN vs CC straightbred dams.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1982

Beef cattle breeding à la Jefferson.

?Even more than most disciplines in the Animal Sciences, quantitative genetics is dependent upon models. Models, by definition, are abstractions of reality. Invariably they require simplifying assumptions, which should be but sometimes are not clearly specified. One thesis of this article, illustrated by examples, is that many of the assumptions upon which animal breeding theory and practice are based are not valid. Some proportion of research resources should be devoted to challenging or verifying those assumptions and following up those areas of enquiry suggested by the outcome of such research. A further thesis is that the selection of topics and priorities for animal breeding research should be a matter of choice by individual scientists and should not be determined by steering committees or directed by administrative fiat. Hopefully, the resultant mutation, cross-fertilization, assortment, recombination and selection of ideas that would result would bestow upon our discipline higher fitness from multiple-peak epistasis, and minimal danger of extinction (or petrification) from over-specialization. A final thesis is that true creativity by research scientists should be nurtured and rewarded and that work in traditional areas of breeding and quantitative genetics should be continued-but done better.

Animals↗

PubMed1981

Possibilities for genetic manipulation of sex ratio in livestock.

Reports are reviewed in which genetic differences for sex ratio of offspring were found among breeds, breed crosses, strains, lines, line crosses, families or individuals. Although reports in which genetic variation could not be identified outnumber those in which it could, important genetic variation does exist in at least some populations. The direct or correlated response of sex ratio to selection is reviewed. Again, results are equivocal, but there is ample evidence that sex ratio will respond to selection in at least some populations of laboratory organisms. Segregation distortion in the mouse and in Drosophila is examined. Segregation distortion occurs when a heterozygous male mated to a homozygous female does not produce the two offspring types in equal proportions and the disparity cannot be accounted for by sampling or differential mortality. Although the most well-known systems have no effect (in the mouse) or only a moderate effect (in Drosophila) on sex ratio, systems in which sex ratio is subject to segregation distortion are known to exist in insects and could exist in mammals. Finally, the possibility is discussed that XX/XY chromosome chimaeric bulls, born co-twin to a heifer, might produce a preponderance of heifer progeny. A few reports suggest this might be the case, but other research is not in agreement.

Animals↗

PubMed1981

Genetic differences in concentration of immunoglobulins G1 and M in serum and colostrum of cows and in serum of neonatal calves.

Blood samples obtained 24 and 36 hr postparturition from 187 calves in 2 years were analyzed for serum concentration of immunoglobulins G1 (IgG1) and M (IgM). Serum and colostrum samples also were obtained from their dams, and corresponding immunoglobulin levels were determined. Calves were evaluated for their ability to acquire and absorb immunoglobulins and cows for their ability to produce immunoglobulins. Mathematical models included sources of variation for breed of sire, sire within breed, breed of dam, age of dam and sex of calf. Of these factors, breed of sire, breed of dam and age of dam were the most important. Simmental- and Pinzgauer-sired calves tended (p = .07) to have lower IgG1 and IgM levels than calves sired by Hereford, Hereford X Angus and Tarentaise bulls. Calves of Hereford X Angus dams had consistently higher immunoglobulin concentrations than calves of Hereford dams. Hereford X Angus cows tended to have higher colostrum concentrations and lower serum concentrations of the two immunoglobulins than Hereford cows. A fetal sire effect was demonstrated for serum IgM concentrations in that cows mated to Simmental bulls had lower (P = .05) concentrations than cows mated to bulls of other breeds. Advancing age of dam was associated with higher concentrations of immunoglobulins, except for serum IgM in the calf and in the cow. Correlations between serum and colostrum concentrations of both immunoglobulins in the dam were low, as were correlations between cow colostrum concentration and calf serum concentration of IgG1. IgM in the colostrum was positively associated with IgM in calf serum, however. Heritability estimates for calf serum IgG1 concentration were high (.52 +/- .28 and .69 +/- 30 at 24 and 36 hr, respectively), while estimates for heritability of IgM concentrations were intermediate (.30 +/- .26 and .35 +/- .26 at 24 and 36 hr, respectively). There was no evidence that sires within breeds influenced, through the fetus, immunoglobulin concentrations in serum or colostrum of their mates. Relatively high repeatabilities for all traits imply that observed differences among cows were due in part to genetic and (or) permanent environmental differences.

Animals↗