Bovine Milk Production Research Articles

Reconstruction of metabolic network in the bovine mammary gland tissue

Understanding bovine metabolism and its relationship with milk products is important in cow breeding. In the present work, the metabolic network in the mammary gland tissue of cattle was reconstructed with the available bovine genome information using several public datasets from NCBI, Uniprot, and KEGG. The network consisted of 1,743 metabolites named by KEGG compound numbers as nodes and 657 enzymes that catalyzed the corresponding reactions as edges. The characteristics of the network were analyzed. The top 20 hub metabolites were determined, and the mean path length was identified to be 6.52. Moreover, 11 key enzymes with significant changes in expression under the condition of mastitis were identified and analyzed by integrating the microarray expression data of normal and clinical mastitis. Aside from the GATM gene, 10 downregulated enzymes were detected in bovine with mastitis. In addition, many of the identified enzymes were involved in amino acid metabolisms or had a direct connection to amino acid metabolisms. These results indicate that mastitis could affect the expression of enzymes, which is vital in some amino acid metabolisms, resulting in the reduction of milk proteins. The present work provides information that may improve the understanding on bovine milk production and mastitis.

Association between polymorphism in bovine PRKAG3 gene and milk production traits

The aim of the conducted study was to evaluate correlation between genotypes and PRKAG3 compound genotypes and milk production traits (yield of milk, milk fat and milk protein, and protein and fat content in milk). The study covered a herd of 180 Jersey cows. PCR-RFLP method was used for genotyping. The frequencies of alleles that occur mostly and combined genotypes were as follows: T1526G G - 0.57, G 1609A G - 0.92 and for T1526G/G1609A TG/GG - 0.54. The results obtained in the study demonstrated the correlation between analyzed genotypes and selected milk production traits; however they are not statistically significant.

Benchmarking of greenhouse gas emissions of bovine milk production systems for 38 countries

This study quantifies and compares greenhouse gas (GHG) emissions of bovine milk production systems in 38 countries representing 70% of the world's bovine milk production. The analysis was based on the International Farm Comparison Network (IFCN) concept of typical dairy farms and the related globally standardized farms representing 45 dairy regions in 38 countries. Various concepts and coefficients from the literature were used to estimate GHG emission from each farm, and the IFCN software TIPI-CAL was used to conduct a partial life cycle assessment of GHG emissions from dairy production. This approach is seen as a first step towards a global comparison of GHG emissions from various dairy farming systems. Results show that GHG emissions at the farm level are 80 to 307kg CO2-eqv 100/kg of energy corrected milk (ECM), and are lower in developed than in developing countries. Differences were mainly due to the level of intensity (i.e., milk yield/cow) in milk production. Enteric CH4 emissions comprised the highest proportion of GHG emissions. Enteric and manure related emissions accounted for 70–95% of total emissions farms depending on farming system. Comparison of various estimators for enteric CH4 emissions suggests that these values might be underestimated. Therefore, in future research, dairy farms should be categorized into farming clusters based on their production intensity and feed usage, with equations to estimate enteric CH4 emissions specific to cluster.This article is part of the special issue entitled: Greenhouse Gases in Animal Agriculture – Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors; K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson.

Human Milk Protein Production in Xenografts of Genetically Engineered Bovine Mammary Epithelial Stem Cells

BackgroundIn the bovine species milk production is well known to correlate with mammary tissue mass. However, most advances in optimizing milk production relied on improvements of breeding and husbandry practices. A better understanding of the cells that generate bovine mammary tissue could facilitate important advances in milk production and have global economic impact. With this possibility in mind, we show that a mammary stem cell population can be functionally identified and isolated from the bovine mammary gland. We also demonstrate that this stem cell population may be a promising target for manipulating the composition of cow's milk using gene transfer.Methods and FindingsWe show that the in vitro colony-forming cell assay for detecting normal primitive bipotent and lineage-restricted human mammary clonogenic progenitors are applicable to bovine mammary cells. Similarly, the ability of normal human mammary stem cells to regenerate functional bilayered structures in collagen gels placed under the kidney capsule of immunodeficient mice is shared by a subset of bovine mammary cells that lack aldehyde dehydrogenase activity. We also find that this activity is a distinguishing feature of luminal-restricted bovine progenitors. The regenerated structures recapitulate the organization of bovine mammary tissue, and milk could be readily detected in these structures when they were assessed by immunohistochemical analysis. Transplantation of the bovine cells transduced with a lentivirus encoding human β-CASEIN led to expression of the transgene and secretion of the product by their progeny regenerated in vivo.ConclusionsThese findings point to a common developmental hierarchy shared by human and bovine mammary glands, providing strong evidence of common mechanisms regulating the maintenance and differentiation of mammary stem cells from both species. These results highlight the potential of novel engineering and transplant strategies for a variety of commercial applications including the production of modified milk components for human consumption.

Associations between the bovine PPARGC1A gene and milk production traits

The aim of this study was to investigate associations between PPARGC1A genotypes and haplotypes and milk production traits. The study included 181 Jersey cows. The genotypes were identified by the PCR-RFLP method. The frequencies of the most common alleles were as follows: T – 0.63 (c.1892T>C) and A – 0.88 (c.3359A>C). The frequency of the most common haplotype was TC/AA – 0.558. The results showed that there were no statistically significant associations between the individual genotypes of both SNPs and milk traits; however, individuals with the CC/AC haplotype produced significantly (P ≤ 0.05; P ≤ 0.001) less milk and had a significantly (P ≤ 0.001) higher protein content in milk.

Mapping a quantitative trait locus for the concentration of β-lactoglobulin in milk, and the effect of β-lactoglobulin genetic variants on the composition of milk from Holstein-Friesian x Jersey crossbred cows

AIM: To identify quantitative trait loci (QTL) affecting the concentration of β-lactoglobulin in milk, and to evaluate the effect of β-lactoglobulin genetic variants on the concentration of fat, protein and casein in bovine milk. METHODS: A herd of 850 F2 Holstein-Friesian x Jersey crossbred cows was produced through mating six Holstein-Friesian x Jersey F1 bulls of high genetic merit with F1 cows from the national herd. A total of 1,610 herd-test records from 556 second-parity crossbreds were analysed. The concentration of fat, protein and casein in milk was measured at peak, mid- and late lactation, during the production seasons of 2003–2004 and 2004–2005. Liveweight was measured daily. DNA from the F2 animals, their F1 dams and sires, and selected grandsires was genotyped across the genome, initially with 285 microsatellite markers, and subsequently with 6,634 single nucleotide polymorphisms (SNP). RESULTS: A highly significant QTL for the concentration of β-lactoglobulin in milk was identified, which coincided with the position of the β-lactoglobulin gene on bovine Chromosome 11. No other consistently significant QTL for the concentration of β-lactoglobulin in milk were detected. Cows with the BB β-lactoglobulin genotype produced milk with a 30% lower concentration of β-lactoglobulin than cows with the AA genotype. The β-lactoglobulin polymorphism also explained variation in the proportion of casein in total protein. In addition, the percentage of fat was higher for BB than AA animals, whereas the percentage of total protein, mean daily milk yield and liveweight did not differ between AA and BB animals. CONCLUSIONS: A significant QTL determining the concentration of β-lactoglobulin in milk was identified. Selection of animals for the β-lactoglobulin B-allele may enable the production of milk naturally enriched for casein, thus allowing a potential increase in the yield of cheese. There may be additional future value in production of bovine milk more like human milk, where decreasing the concentration of β-lactoglobulin is desirable.

Frecuencia del polimorfismo β-lactoglobulina en una población de ganado Holstein de la Sabana de Bogotá

El departamento de Cundinamarca participa con aproximadamente 27% de la producción de leche en Colombia, con desventajas competitivas en cuanto a la calidad del producto (proteína, grasa y sólidos totales); lo cual influye en su participación en el mercado, ya que las empresas lácteas elaboran sus esquemas de pago basándose en estas características de producción. Debido a esta situación, Corpoica ha implementado programas de mejoramiento basados en la selección asistida por marcadores moleculares. Bajo este esquema, se han encontrado diversos polimorfismos genéticos asociados con características de producción de leche bovina; particularmente, en el exón 4 del gen de β-lactoglobulina, donde se ha descrito una variante asociada con producción de caseínas y grasa. El objetivo del presente estudio fue estimar las frecuencias alélicas y genotípicas de β-lactoglobulina en seis poblaciones Holstein de la sabana de Bogotá, mediante la técnica de PCR-RFLP. Para la genotipificación se amplificó un fragmento de 247 pb, digerido con la enzima de restricción Hae III. Las frecuencias de los alelos A y B encontradas en la población son similares (0,51 y 0,49 respectivamente). Estos valores coinciden con los reportados en ganado Holstein europeo. Sin embargo, la distribución de frecuencias genotípicas varía de las frecuencias reportadas mundialmente para ganado lechero. El principal genotipo encontrado fue el AA (0,35), seguido por el BB (0,31). La distribución de los genotipos y de los alelos en la población fue muy similar, lo cual puede estar relacionado con la falta de implementación de programas de mejoramiento en la sabana de Bogotá.

Bovine tuberculosis and milk production in infected dairy herds in Ireland

This study describes the relationship between bovine tuberculosis (TB) and milk yield in TB-infected dairy herds in Ireland. The study had two objectives: to determine whether cows detected as TB reactors (and thus subject to immediate slaughter) were likely to be the higher milk-producing cows, and to determine whether subclinical TB infection was associated with reduced milk production at or around the time of disclosure (detection). All Irish dairy herds restricted from trading between the 1 st June 2004 and the 31 st May 2005 as a result of two or more TB reactors by the Single Intradermal Comparative Tuberculin Test (SICTT) were considered for study. The data consisted of 419 herds. Data were collected on all TB reactors and a random sample of 5 non-reactor cows in these herds: a data set of 4340 cows (2342 TB reactors and 1998 non-reactors). Previous milk data for the cows were taken into consideration and thus all lactations on a cow were analysed together with the years of lactations. There was an inherent hierarchical structure in the data, with lactations nested within cows and cows within herds and thus a linear mixed model with two random effects was used to describe the data. The results of this study showed that for all lactations and years under investigation, milk yield was significantly lower for TB reactor cows, with differences ranging from 120 kg (2003, lactation 3) to 573 kg (2001, lactation 1), when compared to the non-reactor cows.

Preparado de anticorpos policlonais como aditivo alimentar para bovinos

Nas últimas décadas tem sido notável o desenvolvimento mundial na produção de carne e leite bovina. Na área de manejo nutricional, a utilização de ionóforos tem sido imprescindível para otimizar a eficiência das dietas utilizadas e prevenir os distúrbios metabólicos que podem ser provocados pelo aumento da proporção de alimentos prontamente fermentescíveis presentes na dieta. Porém, a busca do mercado consumidor por produtos de origem animal oriundos de criações que utilizam a menor quantidade de substâncias sintéticas quanto possível, abre espaço para a pesquisa de novos aditivos alimentares. Neste contexto, surge a possibilidade da utilização do conceito de imunização passiva para manipulação da fermentação ruminal através de anticorpos policlonais produzidos contra bactérias ruminais específicas. Assim, esta revisão bibliográfica tem como objetivo apresentar os resultados com a utilização desses produtos para manipulação da fermentação ruminal.

Combining mouse mammary gland gene expression and comparative mapping for the identification of candidate genes for QTL of milk production traits in cattle

BackgroundMany studies have found segregating quantitative trait loci (QTL) for milk production traits in different dairy cattle populations. However, even for relatively large effects with a saturated marker map the confidence interval for QTL location by linkage analysis spans tens of map units, or hundreds of genes. Combining mapping and arraying has been suggested as an approach to identify candidate genes. Thus, gene expression analysis in the mammary gland of genes positioned in the confidence interval of the QTL can bridge the gap between fine mapping and quantitative trait nucleotide (QTN) determination.ResultsWe hybridized Affymetrix microarray (MG-U74v2), containing 12,488 murine probes, with RNA derived from mammary gland of virgin, pregnant, lactating and involuting C57BL/6J mice in a total of nine biological replicates. We combined microarray data from two additional studies that used the same design in mice with a total of 75 biological replicates. The same filtering and normalization was applied to each microarray data using GeneSpring software. Analysis of variance identified 249 differentially expressed probe sets common to the three experiments along the four developmental stages of puberty, pregnancy, lactation and involution. 212 genes were assigned to their bovine map positions through comparative mapping, and thus form a list of candidate genes for previously identified QTLs for milk production traits. A total of 82 of the genes showed mammary gland-specific expression with at least 3-fold expression over the median representing all tissues tested in GeneAtlas.ConclusionThis work presents a web tool for candidate genes for QTL (cgQTL) that allows navigation between the map of bovine milk production QTL, potential candidate genes and their level of expression in mammary gland arrays and in GeneAtlas. Three out of four confirmed genes that affect QTL in livestock (ABCG2, DGAT1, GDF8, IGF2) were over expressed in the target organ. Thus, cgQTL can be used to determine priority of candidate genes for QTN analysis based on differential expression in the target organ.

Characterization of the DGAT1 Gene in the New Zealand Dairy Population

Recently, DGAT1 was identified as the gene that underlies the QTL for bovine milk production on chromosome 14. This study investigated the effect of the reported polymorphism in three dairy breeds in New Zealand. Statistically significant results were identified for milk fat, milk protein, and volume for Jersey and Holstein-Friesian breeds, and only milk volume for Ayrshires. The average allele substitution effects were 2 to 3kg of protein and 120 to 130l milk for both the Jersey and Holstein-Friesian breeds. For milk fat, the average allele substitution effect was 6kg for Holstein-Friesians and 3kg for Jerseys. In all breeds, where the polymorphism increased milk fat yield, it decreased milk protein yield and milk volume.

Associations between <i>Leu/Val</i> polymorphism of growth hormone gene and milk production traits in Black-and-White cattle

Abstract. Associations between polymorphism of the bovine growth hormone (GH) gene (Leu/Val) and milk production traits of Black-and-White cattle with different proportional share of Holstein Friesian genes were analysed. A total of 1086 cows were included in the study. PCR-RFLP method was used for genotyping. The frequencies of genotypes and alleles were as follows: 0.653 for LL genotype, 0.324 for LV and 0.023 for VV, and 0.815 for GHL and 0.185 for GHV. Associations between Leu/Val polymorphism and milk production traits of cows were found only in first lactation. Cows with LL genotype had higher milk, fat and protein yield compared to LV individuals (P ≤ 0.01).

Hazard Assessment of Listeria monocytogenes in the Processing of Bovine Milk

The steps in Grade A production of bovine milk for human consumption were assessed. A cumulative distribution of values, based on published data, was used to evaluate steps for milking, storage, transportation and pasteurization. Conservative estimates of parameters in the distributions were used to compute concentrations and probabilities. Under normal operations, the probability was less than 2 in 100 that one Listeria monocytogenes cell occurs in every 2 gallons of milk processed at exactly 71.7°C for 15 s. The probability was less than 2 in 100 that one cell occurs in 3.8 × 1010 gallons processed at 74.4°C for 20 s.

Associations between the bovine major histocompatibility complex (BoLA) and milk production in Icelandic dairy cattle

Associations between BoLA type and milk production were investigated using information from 80 Icelandic cattle from four dairy farms in Iceland. The specificity w6 reduced milk, fat and protein yield. Although w6 has been shown to be associated with increased susceptibility to mastitis, there is no evidence to suggest that the reduced yields here were due to mastitis. The association may be due to increased disease susceptibility or due to a direct effect of BoLA Class I antigens.