Biomedical subjects

A E Freeman

Publications and source records attributed to A E Freeman.

At least 55 records · Page 3Linked to original sources

PubMed1991

Bovine sire effects on daughters' in vitro blood neutrophil functions, lymphocyte blastogenesis, serum complement and conglutinin levels.

Blood neutrophil functions, lymphocyte blastogenic responses, serum complement, and serum conglutinin activity of 98 lactating Holstein cows from two genetic lines were evaluated. The genetic lines were produced in a selection experiment that created and perpetuated genetic differences in milk production for up to seven generations. No significant differences between the two genetic lines of cows were found for neutrophil function, lymphocyte blastogenic responses, serum complement levels, or serum conglutinin levels. Significant differences between sire progeny groups within lines were found for unstimulated and mitogen-stimulated lymphocyte blastogenesis (P less than 0.0001), and almost all neutrophil functions (antibody independent neutrophil cytotoxicity, antibody dependent neutrophil cytotoxicity, ingestion of bacteria, iodination, chemiluminescence, chemokinesis, and chemotaxis (P less than or equal to 0.05)). Sire progeny group differences (P less than or equal to 0.0001) within lines for serum complement and conglutinin activity were also found. Neutrophil chemiluminescence activity (positive relationship; P less than or equal to 0.001), concanavalin A-stimulated lymphocyte blastogenesis (positive relationship; P less than or equal to 0.004), and serum conglutinin activity levels (negative relationship; P less than or equal to 0.01) each had small but significant associations with the total milk somatic cell count. Cows seropositive for bovine leukosis virus had increased resting and mitogen-stimulated lymphocyte blastogenic activity and were associated with increased in vitro neutrophil random migration and production of superoxide anion. Estimates of genetic parameters of various immune cell functions, of serum complement and of conglutinin levels for daughters of 11 sires with 4-6 daughters in the data set were determined. In this report, genetic variation was demonstrated for nonspecific humoral and cellular immunity.

Animals↗

PubMed1991

Association of class I bovine lymphocyte antigen complex alleles with in vitro blood neutrophil functions, lymphocyte blastogenesis, serum complement and conglutinin levels in dairy cattle.

Ninety-eight lactating Holstein cows from two genetic lines selected for high and average milk production were used in the study. Five peripheral blood samples were collected over a 60-day period from each cow for evaluation of neutrophil function, lymphocyte blastogenesis, leukocyte count, and serum complement and conglutinin levels. Blood samples were typed for antigens encoded by alleles at the bovine major histocompatibility complex (BoLA) A locus. Alleles w14(w8), w20A, and w19(w6) were the most frequent of 14 alleles present in this herd. Association of BoLA type with immune function results was examined by using gene substitution models including and ignoring sire effects. Alleles w15(w8) and w16 were associated with greater circulating mononuclear cell and total leukocyte numbers, while w27(w10), w11, and w20A were associated with lower numbers of these cell types. Alleles EU28D and w20A were positively and negatively associated with granulocyte percentage, respectively. Allele w16 was associated with greater antibody-independent neutrophil cytotoxicity, unstimulated lymphocyte proliferation, serum conglutinin activity, and with lower antibody-dependent neutrophil cytotoxicity. Allele w19(w6) was associated with decreased conglutinin activity and decreased neutrophil iodination. Increased antibody-dependent neutrophil cytotoxicity was observed for animals bearing allele w14(w8), and decreased neutrophil iodination, serum conglutinin, and nonstimulated lymphocyte blastogenesis were observed in individuals carrying w20A or EU28D. Significance of both sire and BoLA complex effects suggests that both major histocompatibility complex genes and background genes of the sire significantly affect immune function. This research suggests BoLA-A locus genes may be major genes or markers for closely linked major genes involved in regulation of nonspecific immune function.

Alleles↗

PubMed1991

Replacement of bovine mitochondrial DNA by a sequence variant within one generation.

Inheritance of mitochondrial DNA (mtDNA) in Holstein cattle was characterized by pedigree analysis of nucleotide sequence variation. mtDNA was purified from leukocytes of 174 individuals representing 35 independent maternal lineages, and analyzed for nucleotide sequence variation by characterization of restriction fragment length polymorphism and direct sequence determination. These data revealed 11 maternal lineages in which leukocytes from some individuals seemingly were homoplasmic for the reference mtDNA sequence at nucleotide 364, whereas those from other individuals were homoplasmic for a sequence variant at this position. Both alternative alleles were detected in all branches of these 11 lineages, suggesting that mutation at nucleotide 364 and fixation of the variant sequence occurred frequently in independent events. Thirteen instances were detected of mother-daughter pairs in which leukocytes of each of the two animals seemingly were homoplasmic for a different allele at nucleotide 364, demonstrating the bovine mitochondrial genome can be replaced completely by a nucleotide sequence variant within a single generation. The two alternative sequences seemingly arose de novo at similar frequency, ruling out replicative advantage or other selective bias as the explanation for rapid fixation of mutations at nucleotide 364. Another instance of intralineage sequence variation was detected at nucleotide 5602. This variation was detected in only one of the lineages examined, and evidently arose within three generations.

Alleles↗

PubMed1991

Genetics of health traits in Holstein cattle.

Incidences of 22 health related traits were analyzed for 11,008 lactation records provided by 21st Century Genetics. Traits were analyzed both individually and grouped into one of five health categories. Significant sources of variation included herd-year, lactation, cow, and sire effects. Genetic parameters were estimated with multiple-trait REML. Repeatability and heritability estimates were low to moderate. Estimates ranged from .09 to .57 for repeatability and from .02 to .21 for heritability when individual traits were pooled by health category. Reproductive and respiratory traits were the least heritable (less than .10); mammary and locomotive traits were slightly higher (less than .20); and digestive category was most heritable (.21). Genetic correlations of mature equivalent milk with number of inseminations and other reproductive problems were positive (antagonistic), but those with incidences of other health problems were negative. Phenotypic correlations among mature equivalent milk and fat with individual health traits and categories of health traits were small and mostly near zero. Genetic correlations among health traits were positive except for reproduction with mammary and respiratory traits. Phenotypic correlations among health traits were near zero. Results suggest that selection for reduction of health problems is possible. If selection is practiced for improved health, these health traits should be properly weighted relative to production and other traits by the appropriate economic value. Evaluation of animals for health problems should be done on a multiple-trait basis.

Animals↗

PubMed1991

Effect of season, genetic line, and sire on growth concentrations of somatotropin in serum of Holstein cows in early lactation.

To determine the effect of selection for milk yield on somatotropin concentrations, blood samples were collected from 128 Holstein cows whose sires had either high or average predicted differences for milk. The phenotypic difference in milk yield between the high and average yielding groups was 1726 kg on a 305-d mature equivalent basis. At 37 +/- 7 d postpartum, four blood samples were taken from each cow at 1-h intervals beginning at 0800 h. The statistical model contained genetic line, sires within line, and season as whole-plot effects and time of sampling as a subplot effect. The concentration of growth hormone was significantly higher in the high yielding group (1.89) than in the average yielding group (1.49). Cows sampled in summer had the highest concentrations of growth hormone, whereas cows sampled in spring had the lowest concentrations. Sires did not significantly influence the somatotropin concentration of their progeny. In a second analysis with seven extreme outliers (peak values) deleted, the variation of somatotropin concentrations in the cows was significantly accounted for by their sires. Repeatability of somatotropin concentration was .49 within cows.

Animals↗

PubMed1991

C. R. Henderson: contributions to the dairy industry.

Through C. R. Henderson's position and the application of his knowledge, he had a major influence on genetic improvement in dairy cattle beginning in the 1950s. He developed herdmate comparisons in the United States. The first extensive program using pedigree selection and progeny testing of sires for use in AI was because of his suggestion. This program established the direction of dairy cattle improvement that still continues. He developed BLUP and discovered how to write the inverse of an additive genetic relationship matrix, A-1, without inverting the matrix. These accomplishments had a major impact on evaluation methods of dairy cattle and other livestock species. Use of BLUP and A-1 are standards for evaluation of breeding values all over the world. His pioneering work in estimation of components of variance and analyses of unbalanced data were also of primary importance for animal evaluation and many other applications. Henderson made a major contribution to mankind.

Animals↗

PubMed1991

Comparison of natural transmission of bovine leukemia virus in Holstein cows of two genetic lines selected for high and average milk production.

One hundred and fifty lactating Holstein cows from 2 genetic lines selected for high and average milk production were used in the study. Sera from 6 annual herd tests were analyzed by agar-gel immunodiffusion test for antibodies to bovine leukemia virus. Odds of being seropositive were analyzed by use of stepwise and backward logistic regression procedures. Analysis within birth year revealed that estimated in odds increased by 0.19/year of age among cows of the high genetic line and by 0.43 among cows of the average genetic line. This was accompanied by a more important cohort effect among high producers than among average producers.

Animals↗

PubMed1990

Association of class I bovine lymphocyte antigen complex alleles with health and production traits in dairy cattle.

Ninety-eight Holstein cows from the I-O-State breeding research herd were serologically typed for class I bovine lymphocyte antigens. After exclusion of animals carrying alleles that occurred at frequencies lower than 4%, records from 82 cows that had 161 lactations remained for analysis of major histocompatibility complex allelic effects. A gene substitution model was used to evaluate the additive effects of nine alleles (frequencies of 4 to 20%) at the bovine lymphocyte antigen complex A locus on general health, udder health, and production traits. Allele w14(w8) was associated with decreased quarter milk sample California Mastitis Test scores, composite milk sample California Mastitis Test and Wisconsin Mastitis Test scores, decreased total health costs, and with increased milk yield, fat yield, fat percentage, and income over feed costs. Allele w11 was associated with decreased clinical mastitis, discarded milk, and udder health costs but was also associated with decreased fat yield, fat percentage, and income over feed costs. Allele w31(w30) was associated with decreased fat percentage. These relationships suggest that alleles at the bovine lymphocyte antigen complex A locus may serve as markers for health and production traits. Thus, the potential may exist for enhancement of disease resistance or production in cattle via marker-assisted selection and genetic manipulation techniques using class I genes of the bovine major histocompatibility complex.

Alleles↗

PubMed1990

Increased milk production versus reproductive and energy status of high producing dairy cows.

Two groups of 10 Holstein cows were chosen by pairs from a 20-yr genetic selection project that used either breed average or breed high sires chosen only for Predicted Differences in milk production. Milk production (305-d mature equivalent) was 10,814 kg and 6912 kg for the high and average groups of cows. Days to first visual estrus and number of ovulations before first visual estrus were greater for the high versus the average group (66 vs. 43 d and 1.6 vs. .7 ovulations). No differences were significant between groups for the interval from parturition to uterine involution or for days to first ovulation. Energy balance was less for the high group during wk 1, 2, 10, and 11. Plasma glucose concentration was lowest during wk 2 for both groups, and nonesterified fatty acids and beta-hydroxybutyrate were greatest for both groups during wk 1 and 2. Liver glycogen content was lower at d 15 postpartum for the high group, and liver triglyceride content was greater on d 30 for the high group. The data for reproductive functions support the concept that high milk production is antagonistic to expression of estrous behavior but not to reactivation of ovarian function.

3-Hydroxybutyric Acid↗

PubMed1989

Molecular analysis of cytoplasmic genetic variation in Holstein cows.

Mitochondrial DNA from Holstein maternal lineages implicated to express cytoplasmic genetic effects on lactation traits was subcloned and screened for molecular polymorphisms. Sixteen of 35 lineages sampled differed from the most common mitochondrial DNA form by at least one restriction endonuclease cleavage site in the 4.3 kilobase segment examined. Variation existed in the region that regulates DNA replication and transcription as well as in transfer and ribosomal ribonucleic acid coding regions of the DNA. The index of nucleotide diversity calculated from polymorphism frequencies indicated that the minimum extent of variation between two random lineages was 1.16 x 10(-4) nucleotide differences per base pair in the segment examined. Presence of a HpaII marker near nucleotide 360 was associated with lower (P less than .001) milk fat percentages. Molecular markers indicated that pedigrees may not be sufficient to separate true cytoplasmic lineages for quantitative genetic analyses. These findings provide a molecular genetic basis for further study of cytoplasmic effects on phenotypic variation in Holstein cattle.

Animals↗

PubMed1989

Characteristics of mammary mitochondria in lines of mice genetically divergent for milk production.

The purpose of this study was to determine the relationship of mitochondrial proliferation and ATP production to milk production in two lines of mice that were genetically divergent for milk production. Milk production differed between high production and low production lines by .8 phenotypic standard deviations as determined by cross-fostered litter weight gain from 1 to 12 d postpartum. Mammary weight, mammary total DNA, and RNA:DNA ratio were greater in glands of high line mice. Mammary DNA and protein, expressed per gram mammary tissue, were similar between lines. Mammary mitochondrial mass per gland differed after six generations of divergent selection. Rates of succinate-supported ATP production and ADP:O of isolated mitochondria differed, but the rate of pyruvate-supported ATP production did not differ between lines. Differences between selection lines in mitochondrial mass and in the efficiency of succinate use for support of ATP production were probable consequences of selection for divergent milk production.

Adenosine Triphosphate↗

PubMed1989

Selection for the direct and maternal genetic effects for dystocia in Holsteins.

The effects of selection for the direct and maternal components of dystocia were estimated for first, second and later, and all parities. The effect of restricting maternal change to zero and the effect of selection for only the direct component were also examined. Gene flow procedure was used to compute economic weights as 1 and .347 for the direct and maternal effects, respectively. Genetic gain in aggregate genotype was the largest for first parity. For all parities all the gain in the aggregate genotype was accounted for by the direct effects. At the same time, a slight decrease in the genetic maternal effects was observed. For all cases, selection for both traits had almost no loss in aggregate genotype or accuracy compared with when maternal changes were restricted to zero. Total genetic gain and genetic gain for the direct effect of dystocia were greater and accuracy of selection was lower when selection was for the genetic direct effect only versus the index that included both direct and maternal effects. Selection for only the direct effects is not likely to produce any significant change in dystocia as a maternal trait.

Animals↗

PubMed1989

Effects of body measurements and weight on calf size and calving difficulty of Holsteins.

Body measurements (heart and paunch girths, wither height, chest depth, pelvic length and width, and body length), body weight, and calving evaluation data (calf birth weight, calf sex, calf presentation, and calving assistance needed) were collected from 1974 parities of 762 Holstein cows between 1968 and 1986. Degree of calving assistance was scored continuously from 1 (no assistance) to 10 (hard mechanical assistance). Phenotypic correlations of dam body traits with calf birth weight were all significantly positive when combined for all parities and ranged from .23 for paunch girth to .27 for body weight and heart girth. Correlations of dam body traits with calving assistance scores were all significantly negative across parities and ranged from -.24 to -.30. Correlations of calf birth weight with calving assistance were higher for first parity (.37) than for all parities (.20). Least squares analysis showed that cows with shorter wither height and shorter pelvises tended to require more calving assistance. Heavier calves, winter calvings, and earlier parity all were related to increased dystocia. Male calves were heavier than female calves and also were associated with greater calving difficulty.

Animals↗

PubMed1988

Comparison between factor analysis from a phenotypic and genetic correlation matrix using linear type traits of Holstein dairy cows.

Data on 18 linear type scores and production data for 43,428 records by 228 sires were used to compare two different factor-analyses procedures. Using a genetic correlation matrix to obtain a genetic factor matrix showed that the number of derived factors could be reduced to seven genetic factors vs. eight phenotypic factors. Genetic factors provided a good summary of the data and accounted for 79.3% of the total variation vs. 69.1% expressed by eight phenotypic factors. A comparison between the use of a genetic and phenotypic multiple regression analysis showed some difference for the basic rank of factor influence on production and herdlife.

Animals↗

PubMed1987

Factor analysis for evaluating relationships between first lactation type scores and production data of Holstein dairy cows.

Data on linear type scores for 18 traits from evaluations from Twenty-First Century Genetics from September 1979 to December 1983 were matched against the DHIA production records. Data for production were 43,428 records by 228 sires, each with at least 20 progeny in at least nine herds. Data were randomly split to analyze and validate the investigation of factor analyses to relate type scores and production. Type scores (1 to 50 points) were adjusted for days in milk and age at first calving. Means of the adjusted type scores ranged from 25.2 to 31.7 (+/- 5.39 to 9.09 SD). A principal component analysis showed that the first eight components accounted for more than 69% of the total variance in type scores. A principal factor analysis followed by a factor rotation was used to define new factors. Multiple linear regression on these factors indicated that herdmate deviation milk and fat are more closely related to characteristics of the mammary system than they are to body traits. For herdlife analyses, using 17,288 records, cows with well-attached udders stayed in herds longer.

Animal Husbandry↗

PubMed1987

Reporting of dystocia scores and effects of dystocia on production, days open, and days dry from dairy herd improvement data.

Dystocia and livability scores are collected through the Mid-States Dairy Records Processing Center. Thirty-four percent of the cows had dystocia scores reported. Least difficult births were scored 1 and the most difficult births scored 5. Days open in first parity were 14 d greater for births scored 5 versus 1. The differences were larger in later parities. There were 26 more d open in second parity and 19 more d open in third and greater parities for score 5 versus 1. Differences between cows scored 5 versus 1 were 465 kg milk and 20.7 kg milk fat in first lactations, 576 kg milk and 20.9 kg milk fat in second lactations, and 725 kg milk and 25 kg milk fat in third and greater lactations. Cows produced more in lactations following an easy birth. Frequency of difficult births was less in lactations other than the first.

Animals↗

PubMed1987

Effects of previous days open, previous days dry, and present days open on lactation yield.

Influences of days open present lactation, days open previous lactation, and days dry previous lactation were fit simultaneously to determine their effects on measures of yield, which were fat-corrected milk, milk, and milk fat, all adjusted to a 305-d mature equivalent basis. Best linear unbiased estimates were obtained. Multiparity analyses were conducted using a model in which later parity records could be compared with more unselected first parity records. Additional parity information made little difference in the influence of previous days dry and previous and present days open on yield. As present days open increased from 20 to 300 d, lactation yields for FCM, milk, and milk fat increased approximately 1250, 1350, and 45 kg. As previous days open increased from 20 to 300 d, lactation yields for FCM, milk, and milk fat increased approximately 625, 650, and 25 kg. Cows dry 60 to 69 d gave the most milk the following lactation. Cows dry less than 40 d produced much less milk the next lactation. Heritability estimates for previous days dry were less than 7%. Multiplicative adjustment factors were developed to adjust lactation yield records for the largely environmental effects of days open and days dry.

Animals↗

PubMed1987

Ordered categorical sire evaluation for dystocia in Holsteins.

New statistical procedures for analysis of ordered categorical data were investigated. In using the standardized threshold model, scores are transformed to estimate unknown boundary points and fixed and random effects on an underlying scale of continuous response. The model for calving ease included sex of calf, parity of dam, and the unknown boundary points as fixed effects; herd-year-seasons and sires were random. Data were 5029 dystocia scores on a scale of 1 to 5 collected from June 1982 to January 1984 through the Mid-States Dairy Records Processing Center. The predicted probability of a difficult birth by an average sire indicated that twice as many males as females are born with difficulty. Difficult births declined between first and second parity by a factor of 5. Herd-year-seasons accounted for 13.3% of the variance and sires 3.2%. Heritability on the underlying scale was higher (.147) than on the observed scale (.061). Rank correlations among the threshold model sire solutions and best linear unbiased predictions were .94 when herd-year-seasons were fixed, .98 with random herd-year-seasons, and .99 with normalized scores. Predicted percentage of difficult births for all sires in the analysis ranged from 6 to 18%.

Animals↗