lymphocytes using magnetic assisted cell sorting. Monocytes were cultured with interferon-g or in... more lymphocytes using magnetic assisted cell sorting. Monocytes were cultured with interferon-g or interleukins (IL) 4 and 13 to induce a classical or alternative macrophage phenotype, respectively, then stimulated with lipopolysaccharide. Macrophage mRNA was quantified in adipose using qPCR. Fold changes in mRNA concentration were calculated by 2-DDCt , using the untreated cells as calibrator and three endogenous control mRNA. Treatment differences in mRNA expression were identified using Fisher pairwise comparisons and ANOVA (P £ 0.05). Flow cytometry showed magnetic assisted cell sorting increased CD172a + cells from 22.3 ± 1.9 to 81.6 ± 2.8%. After 48 h in vitro, CD68 expression increased and CD172a + was 95.2 ± 0.4%. Lipopolysaccharide increased IL6, IL10, TNF, and CCL2 expression. Lipopolysaccharide stimulated IL6 and IL10 expression was decreased in alternative macrophages, whereas lipopolysaccharide stimulated TNF expression was increased in classical macrophages. Lipopolysaccharide stimulated CCL2 expression was not different between macrophage types. Together these results show an exacerbated proinflammatory cytokine profile in a model of classical bovine macrophages during gram negative bacterial disease. Results suggest that macrophage phenotype could be involved with severe inflammatory responses seen during dairy cow periparturient periods characterized by prolonged and exacerbated lipolysis and increased disease susceptibility. Ongoing research will describe macrophage phenotype during bovine disease and identify factors contributing to phenotype change. Such factors could ultimately be manipulated to control the bovine macrophage inflammatory response.
Functional traits in dairy cows include fertility, health, longevity, and other traits that affec... more Functional traits in dairy cows include fertility, health, longevity, and other traits that affect efficiency of dairy operations by decreasing input rather than increasing output. Genetic improvement of functional traits is challenging because of low heritabilities and difficulties related to phenotype recording. Application of genomics-assisted selection seems to be promising for functional traits. In the scope of this study, genomic predictions for several traits describing various aspects of mastitis, reproduction, and postpartum metabolic disorders were developed using a 50K SNP panel. The reference population included over 4,500 Holstein cows sampled from 9 large commercial herds located in 5 different states in the US. The animals had complete pedigree and extensive phenotype information for the traits of interest. The validation population included about 1,200 Holstein cows from an independent herd. The phenotypes of all animals, along with the pedigree consisting of 14,685 ...
T16 The effect of a fish oil based-product and canola oil on blood lactate, rectal temperature, h... more T16 The effect of a fish oil based-product and canola oil on blood lactate, rectal temperature, health, daily gain, and starter intake on Holstein dairy calves. P. Melendez*1, C. Roeschmann2, A. Baudo3, S. Tao1, J. Bernard1, P. Pinedo4, and F. Farcey5, 1University of Georgia, Tifton, GA, 2University of Chile, Santiago, Chile, 3Abraham Baldwin Agricultural College, Tifton, GA, 4Colorado State University, Fort Collins, CO, 5National University La Pampa, Gral. Pico, Argentina.
J. Anim. Sci. Vol. 83, Suppl. 1/J. Dairy Sci. Vol. 88, Suppl. 1 to unselected controls (CO). The ... more J. Anim. Sci. Vol. 83, Suppl. 1/J. Dairy Sci. Vol. 88, Suppl. 1 to unselected controls (CO). The selection line had an increase of 3.0 corpora lutea (CL) and an increase of 0.3 pigs in total litter size as compared to controls. DNA was collected from 262 CO and 258 OR gilts and boars at generations 12 and 13. Six microsatellite markers, including two utilized in validation of the QTL, that spanned from 69cM to 96cM were genotyped. Utilizing SAS/Genetics, the marker which had showed the most significant (P<0.001) divergence between OR and CO lines was SW1041 (69cM). Significant differences (P<0.001) of SW1041 alleles on CL were identified with a model including allele, line, year born, season born, and sire as a random effect. The most frequent SW1041 allele in the OR line was associated with the second largest CL mean. Two markers (SWR1829, SW951) had the most frequent OR allele associated with greatest CL mean. An additional two markers (MRC1MS, GAD2) had an increase in the f...
The objectives of this study were to assess antibody and cellular immune responses in first-lacta... more The objectives of this study were to assess antibody and cellular immune responses in first-lactation dairy heifers reared under a pasture-based production system and to investigate associations between immune competence and stress responsiveness, health, and productivity. A commercial vaccine was used to induce antibody and cellular immune responses and, based on measured responses, animals were classified as above average, average, and below average for each trait independently and in combination (overall immune competence). Overall immune competence phenotypic rankings were generated by combining standardized residual values for antibody and cellular responses measured in individual heifers. Cortisol responses to handling and yarding were used to assess stress responsiveness, worm egg counts were used to assess internal parasite burden, somatic cell counts to assess udder health and estimates of total daily milk volume, and milk fat and milk protein contents to assess productivity. A total of 393 Holstein-Friesian and Holstein-Friesian × Jersey crossbred heifers from 2 herds practicing seasonal calving in a pasture-fed production system were enrolled in the study. The immune competence phenotypes of individual heifers were assessed before their first mating and their subsequent performance during their first lactation was monitored. Animals with below-average antibody and cellular immune competence had higher serum cortisol concentrations compared with their counterparts following handling, suggesting they had a reduced ability to cope with management-induced stress. Furthermore, a significant negative (favorable) correlation was observed between antibody responses and stress responsiveness. Similarly, correlations between antibody responses and internal parasite burden were significant and negative (favorable). No correlations were observed between overall immune competence and milk yield, milk fat, and milk protein content.
The fatty acid profile of milk is a prevailing issue due to the potential negative or positive ef... more The fatty acid profile of milk is a prevailing issue due to the potential negative or positive effects of different fatty acids to human health and nutrition. Mid-infrared spectroscopy can be used to obtain predictions of otherwise costly fatty acid phenotypes in a widespread and rapid manner. The objective of this study was to evaluate the prediction of fatty acid content for the Canadian dairy cattle population from mid-infrared spectral data and to compare the results produced by altering the partial least squares (PLS) model development set used. The PLS model development sets used to develop the predictions were reference fatty acids expressed as (1) grams per 100 g of fatty acid, (2) grams per 100 g of milk, (3) the natural logarithmic transform of grams per 100 g of milk, and (4) subsets of samples randomly selected by removing excess records around the mean to present a more uniform distribution, repeated 10 times. Gas chromatography measured fatty acid concentration and spe...
The objective of this study was to estimate the heritability of milk fat globule (MFG) size and m... more The objective of this study was to estimate the heritability of milk fat globule (MFG) size and mid-infrared (MIR) predicted MFG size in Holstein cattle. The genetic correlations between measured and predicted MFG size with milk fat and protein percentage were also investigated. Average MFG size was measured in 1,583 milk samples taken from 254 Holstein cows from 29 herds across Canada. Size was expressed as volume moment mean (D[4,3]) and surface moment mean (D[3,2]). Analyzed milk samples also had average MFG size predicted from their MIR spectral records. Fat and protein percentages were obtained for all test-day milk samples in the cow's lactation. Univariate and bivariate repeatability animal models were used to estimate heritability and genetic correlations. Moderate heritabilities of 0.364 and 0.466 were found for D[4,3] and D[3,2], respectively, and a strong genetic correlation was found between the 2 traits (0.98). The heritabilities for the MIR-predicted MFG size were ...
The objectives of this study were to investigate the sources of variation in milk fat globule (MF... more The objectives of this study were to investigate the sources of variation in milk fat globule (MFG) size in bovine milk and its prediction using mid-infrared (MIR) spectroscopy. Mean MFG size was measured in 2,076 milk samples from 399 Ayrshire, Brown Swiss, Holstein, and Jersey cows, and expressed as volume moment mean (D[4,3]) and surface moment mean (D[3,2]). The mid-infrared spectra of the samples and milk performance data were also recorded during routine milk recording and testing. The effects of breed, herd nested within breed, days in milk, season, milking period, age at calving, parity, and individual animal on the variation observed in MFG size were investigated. Breed, herd nested within breed, days in milk, season, and milking period significantly affected mean MFG size. Milk fat globule size was the largest at the beginning of lactation and subsequently decreased. Milk samples with the smallest MFG on average came from Holstein cows, and those with the largest were from...
The objectives of this study were to evaluate (1) natural antibodies (NAb) in Canadian Holstein c... more The objectives of this study were to evaluate (1) natural antibodies (NAb) in Canadian Holstein cows, (2) genetic parameters and associations between NAb and specific antibody (SpAb), and (3) the association of NAb with clinical mastitis and differences in incidence rates of clinical mastitis (IRCM) among cows classified as high, average, or low responders for NAb. Natural antibodies (IgG and IgM) to keyhole limpet hemocyanin and SpAb to a type 2 test antigen were measured on 451 Holsteins from 41 herds across Canada. A series of uni- and tri-variate linear animal models were used to estimate genetic parameters and breeding values for NAb and SpAb. The models included the fixed effects of parity and stage of lactation and the random effects of herd-technician, animal, and residual. Using estimated breeding values for NAb, cows were classified as high, average, or low responders and phenotypic associations with the IRCM were investigated and a logistic regression performed. The estim...
The Canadian veterinary journal. La revue vétérinaire canadienne, 1999
Inappropriate comment regarding fees charged by neighboring colleagues-A reply Dear Sir: Thank yo... more Inappropriate comment regarding fees charged by neighboring colleagues-A reply Dear Sir: Thank you for the opportunity to respond to the criticism by Dr. Barton of my answer to the November 1998 ethical question. After much contemplation, I am still not entirely sure of Dr. Barton's point. I am concerned, though, that she has interpreted my comments as an attempt to berate my neighboring colleagues and, if so, I feel they need some explanation. Although the case presented is claimed to be factual, it struck me as being one of the more absurd scenarios to appear in this forum. Perhaps that's what prompted my seemingly obtuse response. Unfortunately, it now seems, I dealt with the question in a hypothetical manner (hence my qualifier "If I had been so foolish and
To better understand the interaction between saturated or unsaturated fatty acids and its effect ... more To better understand the interaction between saturated or unsaturated fatty acids and its effect on expression of genes involved in subcutaneous adipose tissue metabolism, 23 second parity alpine dairy goats were enrolled in the experiment and fed either a non fat-supplemented basal diet (C; n=8), the basal diet supplemented with stearic acid (ST; n=7) or the basal diet supplemented with fish oil (FO; n=8). 30g/head/d supplemental fatty acids during the dry period and 50g/head/d during lactation were delivered starting one week before parturition up to 21 days in milk. Subcutaneous adipose tissue samples were harvested at day-7, 7 and 21 relative to kidding and mRNA levels of genes involved in inflammation were measured via qPCR. Data were analyzed using the MIXED procedure of SAS. No significant effects for treatment were observed, however eight genes were significant for time. HP and SAA3 expression peaked at day 7 postpartum, to then return at prepartum level around 21 d relative to kidding, while IL8, IL10, and IL18 expression constantly increased along the transition period. Vice versa, expression of IL1β, IL6R, and RXRA decreased in response to kidding, with a subsequent increase at day 21. The obtained results led us to hypothesize that goats face a postponed lipomobilization after kidding, probably related to their reduced production. The next step will involve the analysis of miRNA related to immune cell infiltration, adipocyte inflammation and lipolysis and positive regulation of adipogenesis to better understand the complex network of lipid metabolism in periparturient goats.
Background: Breeding for enhanced immune response (IR) has been suggested as a tool to improve in... more Background: Breeding for enhanced immune response (IR) has been suggested as a tool to improve inherent animal health. Dairy cows with superior antibody-mediated (AMIR) and cell-mediated immune responses (CMIR) have been demonstrated to have a lower occurrence of many diseases including mastitis. Adaptive immune response traits are heritable, and it is, therefore, possible to breed for improved IR, decreasing the occurrence of disease. The objective of this study was to perform genome-wide association studies to determine differences in genetic profiles among Holstein cows classified as High or Low for AMIR and CMIR. From a total of 680 cows with immune response phenotypes, 163 cows for AMIR (81 High and 82 Low) and 140 for CMIR (75 High and 65 Low) were selectively genotyped using the Illumina Bovine SNP50 BeadChip. Results were validated using an unrelated population of 164 Holstein bulls IR phenotyped for AMIR and 146 for CMIR. Results: A generalized quasi likelihood score method was used to determine single nucleotide polymorphisms (SNP) and chromosomal regions associated with immune response. After applying a 5% chromosomal false discovery rate, 186 SNPs were significantly associated with AMIR. The majority (93%) of significant markers were on chromosome 23, with a similar peak found in the bull population. For CMIR, 21 SNP markers remained significant. Candidate genes within 250,000 base pairs of significant SNPs were identified to determine biological pathways associated with AMIR and CMIR. Various pathways were identified, including the antigen processing and presentation pathway, important in host defense. Candidate genes included those within the bovine Major Histocompatability Complex such as BoLA-DQ, BoLA-DR and the non-classical BoLA-NC1 for AMIR and BoLA-DQ for CMIR, the complement system including C2 and C4 for AMIR and C1q for CMIR, and cytokines including IL-17A, IL17F for AMIR and IL-17RA for CMIR and tumor necrosis factor for both AMIR and CMIR. Additional genes associated with CMIR included galectins 1, 2 and 3, BCL2 and β-defensin. Conclusions: The significant genetic variation associated with AMIR and CMIR in this study may imply feasibility to include immune response in genomic breeding indices as an approach to improve inherent animal health.
Abstract Text: A total of 1,046 milk samples from 188 Canadian Holstein cows were analyzed for me... more Abstract Text: A total of 1,046 milk samples from 188 Canadian Holstein cows were analyzed for mean milk fat globule size and casein micelle size. Milk fat globule size was calculated as both as volume moment mean and surface moment mean. High heritabilities were found for both expressions of the trait at 0.57 and 0.50, respectively. Additionally, a very high genetic correlation of 0.94 was found between the volume and surface moment means. A heritability of 0.29 was found for casein micelle size. Positive genetic correlations between casein micelle size and milk fat globule volume and surface moment means of 0.16 and 0.11, respectively, were found. The genetic parameters found for the traits examined indicate a genetic component to their size and selection may be possible. Keywords: Dairy cattle, Milk fat globule, Casein micelle
Pigs have been selected for high (H) or low (L) combined antibody and cell-mediated immune respon... more Pigs have been selected for high (H) or low (L) combined antibody and cell-mediated immune response to test the high immune response phenotype as a candidate for an indirect approach to improving health and productivity in livestock. Mycoplasma hyorhinis infection was induced in H and L pigs of the 4th generation of selection to test the hypothesis that immune response lines differ in response to infection. The major disease sign, arthritis, was more severe in the H pigs both clinically and at necropsy. M. hyorhinis was isolated at higher colony counts from synovial fluids of the H pigs. In contrast, pleuritis and peritonitis were less severe in pigs of the H than those of the L line. Pericarditis, although less in H than L pigs, did not differ significantly by line. Synovial fluid antibody to M. hyorhinis did not differ by line but H pigs produced serum antibody earlier and to a higher titre than did L pigs. Selection for H or L immune response therefore alters response to M. hyorhinis, however there is no indication of a consistent line-related health advantage.
A variety of commercial DNA arrays specific for humans and rodents are widely available; however,... more A variety of commercial DNA arrays specific for humans and rodents are widely available; however, microarrays containing well-characterized genes to study pathway-specific gene expression are not as accessible for domestic animals, such as cattle, sheep and pigs. Therefore, a small-scale application-targeted bovine immune-endocrine cDNA array was developed to evaluate genetic pathways involved in the immune-endocrine axis of cattle during periods of altered homeostasis provoked by physiological or environmental stressors, such as infection, vaccination or disease. For this purpose, 167 cDNA sequences corresponding to immune, endocrine and inflammatory response genes were collected and categorized. Positive controls included 5 housekeeping genes (glyceraldehydes-3-phosphate dehydrogenase, hypoxanthine phosphoribosyltransferase, ribosomal protein L19, b-actin, b2-microglobulin) and bovine genomic DNA. Negative controls were a bacterial gene (Rhodococcus equi 17-kDa virulence-associated protein) and a partial sequence of the plasmid pACYC177. In addition, RNA extracted from un-stimulated, as well as superantigen (Staphylococcus aureus enterotoxin-A, S. aureus Cowan Pansorbin Cells) and mitogen-stimulated (LPS, ConA) bovine blood leukocytes was mixed, reverse transcribed and PCR amplified using gene-specific primers. The endocrine-associated genes were amplified from cDNA derived from un-stimulated bovine hypothalamus, pituitary, adrenal and thyroid gland tissues. The array was constructed in 4 repeating grids of 180 duplicated spots by coupling the PCR amplified 213-630 bp gene fragments onto poly-L-lysine coated glass slides. The bovine immune-endocrine arrays were standardized and preliminary gene expression profiles generated using Cy3 and Cy5 labelled cDNA from un-stimulated and ConA (5 mg/ml) stimulated PBMC of 4 healthy Holstein cows (2-4 replicate arrays/cow) in a time course study. Mononuclear cell-derived cytokine and chemokine (IL-2, IL-1a, TNFa, IFN-g, TGFb-1, MCP-1, MCP-2 and MIP-3a) mRNA exhibited a repeatable and consistently low expression in un-stimulated cells and at least a twofold increased expression following 6 and 24 h ConA stimulation as compared to 0 h un-stimulated controls. In contrast, expression of antigen presenting molecules, MHC-DR, MHC-DQ and MHC-DY, were consistently at least twofold lower following 6 and 24 h ConA stimulation. The only endocrine gene with differential expression following ConA stimulation was prolactin. Additionally, due to the high level of genetic homology between ovine, swine and bovine genes, RNA similarly acquired from sheep and pigs was evaluated and similar gene expression patterns were noted. These data demonstrate that this application-targeted array containing a set of well characterized genes
lymphocytes using magnetic assisted cell sorting. Monocytes were cultured with interferon-g or in... more lymphocytes using magnetic assisted cell sorting. Monocytes were cultured with interferon-g or interleukins (IL) 4 and 13 to induce a classical or alternative macrophage phenotype, respectively, then stimulated with lipopolysaccharide. Macrophage mRNA was quantified in adipose using qPCR. Fold changes in mRNA concentration were calculated by 2-DDCt , using the untreated cells as calibrator and three endogenous control mRNA. Treatment differences in mRNA expression were identified using Fisher pairwise comparisons and ANOVA (P £ 0.05). Flow cytometry showed magnetic assisted cell sorting increased CD172a + cells from 22.3 ± 1.9 to 81.6 ± 2.8%. After 48 h in vitro, CD68 expression increased and CD172a + was 95.2 ± 0.4%. Lipopolysaccharide increased IL6, IL10, TNF, and CCL2 expression. Lipopolysaccharide stimulated IL6 and IL10 expression was decreased in alternative macrophages, whereas lipopolysaccharide stimulated TNF expression was increased in classical macrophages. Lipopolysaccharide stimulated CCL2 expression was not different between macrophage types. Together these results show an exacerbated proinflammatory cytokine profile in a model of classical bovine macrophages during gram negative bacterial disease. Results suggest that macrophage phenotype could be involved with severe inflammatory responses seen during dairy cow periparturient periods characterized by prolonged and exacerbated lipolysis and increased disease susceptibility. Ongoing research will describe macrophage phenotype during bovine disease and identify factors contributing to phenotype change. Such factors could ultimately be manipulated to control the bovine macrophage inflammatory response.
Functional traits in dairy cows include fertility, health, longevity, and other traits that affec... more Functional traits in dairy cows include fertility, health, longevity, and other traits that affect efficiency of dairy operations by decreasing input rather than increasing output. Genetic improvement of functional traits is challenging because of low heritabilities and difficulties related to phenotype recording. Application of genomics-assisted selection seems to be promising for functional traits. In the scope of this study, genomic predictions for several traits describing various aspects of mastitis, reproduction, and postpartum metabolic disorders were developed using a 50K SNP panel. The reference population included over 4,500 Holstein cows sampled from 9 large commercial herds located in 5 different states in the US. The animals had complete pedigree and extensive phenotype information for the traits of interest. The validation population included about 1,200 Holstein cows from an independent herd. The phenotypes of all animals, along with the pedigree consisting of 14,685 ...
T16 The effect of a fish oil based-product and canola oil on blood lactate, rectal temperature, h... more T16 The effect of a fish oil based-product and canola oil on blood lactate, rectal temperature, health, daily gain, and starter intake on Holstein dairy calves. P. Melendez*1, C. Roeschmann2, A. Baudo3, S. Tao1, J. Bernard1, P. Pinedo4, and F. Farcey5, 1University of Georgia, Tifton, GA, 2University of Chile, Santiago, Chile, 3Abraham Baldwin Agricultural College, Tifton, GA, 4Colorado State University, Fort Collins, CO, 5National University La Pampa, Gral. Pico, Argentina.
J. Anim. Sci. Vol. 83, Suppl. 1/J. Dairy Sci. Vol. 88, Suppl. 1 to unselected controls (CO). The ... more J. Anim. Sci. Vol. 83, Suppl. 1/J. Dairy Sci. Vol. 88, Suppl. 1 to unselected controls (CO). The selection line had an increase of 3.0 corpora lutea (CL) and an increase of 0.3 pigs in total litter size as compared to controls. DNA was collected from 262 CO and 258 OR gilts and boars at generations 12 and 13. Six microsatellite markers, including two utilized in validation of the QTL, that spanned from 69cM to 96cM were genotyped. Utilizing SAS/Genetics, the marker which had showed the most significant (P<0.001) divergence between OR and CO lines was SW1041 (69cM). Significant differences (P<0.001) of SW1041 alleles on CL were identified with a model including allele, line, year born, season born, and sire as a random effect. The most frequent SW1041 allele in the OR line was associated with the second largest CL mean. Two markers (SWR1829, SW951) had the most frequent OR allele associated with greatest CL mean. An additional two markers (MRC1MS, GAD2) had an increase in the f...
The objectives of this study were to assess antibody and cellular immune responses in first-lacta... more The objectives of this study were to assess antibody and cellular immune responses in first-lactation dairy heifers reared under a pasture-based production system and to investigate associations between immune competence and stress responsiveness, health, and productivity. A commercial vaccine was used to induce antibody and cellular immune responses and, based on measured responses, animals were classified as above average, average, and below average for each trait independently and in combination (overall immune competence). Overall immune competence phenotypic rankings were generated by combining standardized residual values for antibody and cellular responses measured in individual heifers. Cortisol responses to handling and yarding were used to assess stress responsiveness, worm egg counts were used to assess internal parasite burden, somatic cell counts to assess udder health and estimates of total daily milk volume, and milk fat and milk protein contents to assess productivity. A total of 393 Holstein-Friesian and Holstein-Friesian × Jersey crossbred heifers from 2 herds practicing seasonal calving in a pasture-fed production system were enrolled in the study. The immune competence phenotypes of individual heifers were assessed before their first mating and their subsequent performance during their first lactation was monitored. Animals with below-average antibody and cellular immune competence had higher serum cortisol concentrations compared with their counterparts following handling, suggesting they had a reduced ability to cope with management-induced stress. Furthermore, a significant negative (favorable) correlation was observed between antibody responses and stress responsiveness. Similarly, correlations between antibody responses and internal parasite burden were significant and negative (favorable). No correlations were observed between overall immune competence and milk yield, milk fat, and milk protein content.
The fatty acid profile of milk is a prevailing issue due to the potential negative or positive ef... more The fatty acid profile of milk is a prevailing issue due to the potential negative or positive effects of different fatty acids to human health and nutrition. Mid-infrared spectroscopy can be used to obtain predictions of otherwise costly fatty acid phenotypes in a widespread and rapid manner. The objective of this study was to evaluate the prediction of fatty acid content for the Canadian dairy cattle population from mid-infrared spectral data and to compare the results produced by altering the partial least squares (PLS) model development set used. The PLS model development sets used to develop the predictions were reference fatty acids expressed as (1) grams per 100 g of fatty acid, (2) grams per 100 g of milk, (3) the natural logarithmic transform of grams per 100 g of milk, and (4) subsets of samples randomly selected by removing excess records around the mean to present a more uniform distribution, repeated 10 times. Gas chromatography measured fatty acid concentration and spe...
The objective of this study was to estimate the heritability of milk fat globule (MFG) size and m... more The objective of this study was to estimate the heritability of milk fat globule (MFG) size and mid-infrared (MIR) predicted MFG size in Holstein cattle. The genetic correlations between measured and predicted MFG size with milk fat and protein percentage were also investigated. Average MFG size was measured in 1,583 milk samples taken from 254 Holstein cows from 29 herds across Canada. Size was expressed as volume moment mean (D[4,3]) and surface moment mean (D[3,2]). Analyzed milk samples also had average MFG size predicted from their MIR spectral records. Fat and protein percentages were obtained for all test-day milk samples in the cow's lactation. Univariate and bivariate repeatability animal models were used to estimate heritability and genetic correlations. Moderate heritabilities of 0.364 and 0.466 were found for D[4,3] and D[3,2], respectively, and a strong genetic correlation was found between the 2 traits (0.98). The heritabilities for the MIR-predicted MFG size were ...
The objectives of this study were to investigate the sources of variation in milk fat globule (MF... more The objectives of this study were to investigate the sources of variation in milk fat globule (MFG) size in bovine milk and its prediction using mid-infrared (MIR) spectroscopy. Mean MFG size was measured in 2,076 milk samples from 399 Ayrshire, Brown Swiss, Holstein, and Jersey cows, and expressed as volume moment mean (D[4,3]) and surface moment mean (D[3,2]). The mid-infrared spectra of the samples and milk performance data were also recorded during routine milk recording and testing. The effects of breed, herd nested within breed, days in milk, season, milking period, age at calving, parity, and individual animal on the variation observed in MFG size were investigated. Breed, herd nested within breed, days in milk, season, and milking period significantly affected mean MFG size. Milk fat globule size was the largest at the beginning of lactation and subsequently decreased. Milk samples with the smallest MFG on average came from Holstein cows, and those with the largest were from...
The objectives of this study were to evaluate (1) natural antibodies (NAb) in Canadian Holstein c... more The objectives of this study were to evaluate (1) natural antibodies (NAb) in Canadian Holstein cows, (2) genetic parameters and associations between NAb and specific antibody (SpAb), and (3) the association of NAb with clinical mastitis and differences in incidence rates of clinical mastitis (IRCM) among cows classified as high, average, or low responders for NAb. Natural antibodies (IgG and IgM) to keyhole limpet hemocyanin and SpAb to a type 2 test antigen were measured on 451 Holsteins from 41 herds across Canada. A series of uni- and tri-variate linear animal models were used to estimate genetic parameters and breeding values for NAb and SpAb. The models included the fixed effects of parity and stage of lactation and the random effects of herd-technician, animal, and residual. Using estimated breeding values for NAb, cows were classified as high, average, or low responders and phenotypic associations with the IRCM were investigated and a logistic regression performed. The estim...
The Canadian veterinary journal. La revue vétérinaire canadienne, 1999
Inappropriate comment regarding fees charged by neighboring colleagues-A reply Dear Sir: Thank yo... more Inappropriate comment regarding fees charged by neighboring colleagues-A reply Dear Sir: Thank you for the opportunity to respond to the criticism by Dr. Barton of my answer to the November 1998 ethical question. After much contemplation, I am still not entirely sure of Dr. Barton's point. I am concerned, though, that she has interpreted my comments as an attempt to berate my neighboring colleagues and, if so, I feel they need some explanation. Although the case presented is claimed to be factual, it struck me as being one of the more absurd scenarios to appear in this forum. Perhaps that's what prompted my seemingly obtuse response. Unfortunately, it now seems, I dealt with the question in a hypothetical manner (hence my qualifier "If I had been so foolish and
To better understand the interaction between saturated or unsaturated fatty acids and its effect ... more To better understand the interaction between saturated or unsaturated fatty acids and its effect on expression of genes involved in subcutaneous adipose tissue metabolism, 23 second parity alpine dairy goats were enrolled in the experiment and fed either a non fat-supplemented basal diet (C; n=8), the basal diet supplemented with stearic acid (ST; n=7) or the basal diet supplemented with fish oil (FO; n=8). 30g/head/d supplemental fatty acids during the dry period and 50g/head/d during lactation were delivered starting one week before parturition up to 21 days in milk. Subcutaneous adipose tissue samples were harvested at day-7, 7 and 21 relative to kidding and mRNA levels of genes involved in inflammation were measured via qPCR. Data were analyzed using the MIXED procedure of SAS. No significant effects for treatment were observed, however eight genes were significant for time. HP and SAA3 expression peaked at day 7 postpartum, to then return at prepartum level around 21 d relative to kidding, while IL8, IL10, and IL18 expression constantly increased along the transition period. Vice versa, expression of IL1β, IL6R, and RXRA decreased in response to kidding, with a subsequent increase at day 21. The obtained results led us to hypothesize that goats face a postponed lipomobilization after kidding, probably related to their reduced production. The next step will involve the analysis of miRNA related to immune cell infiltration, adipocyte inflammation and lipolysis and positive regulation of adipogenesis to better understand the complex network of lipid metabolism in periparturient goats.
Background: Breeding for enhanced immune response (IR) has been suggested as a tool to improve in... more Background: Breeding for enhanced immune response (IR) has been suggested as a tool to improve inherent animal health. Dairy cows with superior antibody-mediated (AMIR) and cell-mediated immune responses (CMIR) have been demonstrated to have a lower occurrence of many diseases including mastitis. Adaptive immune response traits are heritable, and it is, therefore, possible to breed for improved IR, decreasing the occurrence of disease. The objective of this study was to perform genome-wide association studies to determine differences in genetic profiles among Holstein cows classified as High or Low for AMIR and CMIR. From a total of 680 cows with immune response phenotypes, 163 cows for AMIR (81 High and 82 Low) and 140 for CMIR (75 High and 65 Low) were selectively genotyped using the Illumina Bovine SNP50 BeadChip. Results were validated using an unrelated population of 164 Holstein bulls IR phenotyped for AMIR and 146 for CMIR. Results: A generalized quasi likelihood score method was used to determine single nucleotide polymorphisms (SNP) and chromosomal regions associated with immune response. After applying a 5% chromosomal false discovery rate, 186 SNPs were significantly associated with AMIR. The majority (93%) of significant markers were on chromosome 23, with a similar peak found in the bull population. For CMIR, 21 SNP markers remained significant. Candidate genes within 250,000 base pairs of significant SNPs were identified to determine biological pathways associated with AMIR and CMIR. Various pathways were identified, including the antigen processing and presentation pathway, important in host defense. Candidate genes included those within the bovine Major Histocompatability Complex such as BoLA-DQ, BoLA-DR and the non-classical BoLA-NC1 for AMIR and BoLA-DQ for CMIR, the complement system including C2 and C4 for AMIR and C1q for CMIR, and cytokines including IL-17A, IL17F for AMIR and IL-17RA for CMIR and tumor necrosis factor for both AMIR and CMIR. Additional genes associated with CMIR included galectins 1, 2 and 3, BCL2 and β-defensin. Conclusions: The significant genetic variation associated with AMIR and CMIR in this study may imply feasibility to include immune response in genomic breeding indices as an approach to improve inherent animal health.
Abstract Text: A total of 1,046 milk samples from 188 Canadian Holstein cows were analyzed for me... more Abstract Text: A total of 1,046 milk samples from 188 Canadian Holstein cows were analyzed for mean milk fat globule size and casein micelle size. Milk fat globule size was calculated as both as volume moment mean and surface moment mean. High heritabilities were found for both expressions of the trait at 0.57 and 0.50, respectively. Additionally, a very high genetic correlation of 0.94 was found between the volume and surface moment means. A heritability of 0.29 was found for casein micelle size. Positive genetic correlations between casein micelle size and milk fat globule volume and surface moment means of 0.16 and 0.11, respectively, were found. The genetic parameters found for the traits examined indicate a genetic component to their size and selection may be possible. Keywords: Dairy cattle, Milk fat globule, Casein micelle
Pigs have been selected for high (H) or low (L) combined antibody and cell-mediated immune respon... more Pigs have been selected for high (H) or low (L) combined antibody and cell-mediated immune response to test the high immune response phenotype as a candidate for an indirect approach to improving health and productivity in livestock. Mycoplasma hyorhinis infection was induced in H and L pigs of the 4th generation of selection to test the hypothesis that immune response lines differ in response to infection. The major disease sign, arthritis, was more severe in the H pigs both clinically and at necropsy. M. hyorhinis was isolated at higher colony counts from synovial fluids of the H pigs. In contrast, pleuritis and peritonitis were less severe in pigs of the H than those of the L line. Pericarditis, although less in H than L pigs, did not differ significantly by line. Synovial fluid antibody to M. hyorhinis did not differ by line but H pigs produced serum antibody earlier and to a higher titre than did L pigs. Selection for H or L immune response therefore alters response to M. hyorhinis, however there is no indication of a consistent line-related health advantage.
A variety of commercial DNA arrays specific for humans and rodents are widely available; however,... more A variety of commercial DNA arrays specific for humans and rodents are widely available; however, microarrays containing well-characterized genes to study pathway-specific gene expression are not as accessible for domestic animals, such as cattle, sheep and pigs. Therefore, a small-scale application-targeted bovine immune-endocrine cDNA array was developed to evaluate genetic pathways involved in the immune-endocrine axis of cattle during periods of altered homeostasis provoked by physiological or environmental stressors, such as infection, vaccination or disease. For this purpose, 167 cDNA sequences corresponding to immune, endocrine and inflammatory response genes were collected and categorized. Positive controls included 5 housekeeping genes (glyceraldehydes-3-phosphate dehydrogenase, hypoxanthine phosphoribosyltransferase, ribosomal protein L19, b-actin, b2-microglobulin) and bovine genomic DNA. Negative controls were a bacterial gene (Rhodococcus equi 17-kDa virulence-associated protein) and a partial sequence of the plasmid pACYC177. In addition, RNA extracted from un-stimulated, as well as superantigen (Staphylococcus aureus enterotoxin-A, S. aureus Cowan Pansorbin Cells) and mitogen-stimulated (LPS, ConA) bovine blood leukocytes was mixed, reverse transcribed and PCR amplified using gene-specific primers. The endocrine-associated genes were amplified from cDNA derived from un-stimulated bovine hypothalamus, pituitary, adrenal and thyroid gland tissues. The array was constructed in 4 repeating grids of 180 duplicated spots by coupling the PCR amplified 213-630 bp gene fragments onto poly-L-lysine coated glass slides. The bovine immune-endocrine arrays were standardized and preliminary gene expression profiles generated using Cy3 and Cy5 labelled cDNA from un-stimulated and ConA (5 mg/ml) stimulated PBMC of 4 healthy Holstein cows (2-4 replicate arrays/cow) in a time course study. Mononuclear cell-derived cytokine and chemokine (IL-2, IL-1a, TNFa, IFN-g, TGFb-1, MCP-1, MCP-2 and MIP-3a) mRNA exhibited a repeatable and consistently low expression in un-stimulated cells and at least a twofold increased expression following 6 and 24 h ConA stimulation as compared to 0 h un-stimulated controls. In contrast, expression of antigen presenting molecules, MHC-DR, MHC-DQ and MHC-DY, were consistently at least twofold lower following 6 and 24 h ConA stimulation. The only endocrine gene with differential expression following ConA stimulation was prolactin. Additionally, due to the high level of genetic homology between ovine, swine and bovine genes, RNA similarly acquired from sheep and pigs was evaluated and similar gene expression patterns were noted. These data demonstrate that this application-targeted array containing a set of well characterized genes
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