Genetic variability of lactoferrin content estimated by mid-infrared spectrometry in bovine milk

in Journal of Dairy Science (2007), 90(9), 4443-4450

The effects of lactoferrin (LF) on the immune system have already been shown by many studies. Unfortunately, the current methods used to measure LF levels in milk do not permit the study of the genetic ... [more ▼]

The effects of lactoferrin (LF) on the immune system have already been shown by many studies. Unfortunately, the current methods used to measure LF levels in milk do not permit the study of the genetic variability of lactoferrin or the performance of routine genetic evaluations. The first aim of this research was to derive a calibration equation permitting the prediction of LF in milk by mid-infrared spectrometry (MIR). The calibration with partial least squares on 69 samples showed a ratio of standard error of cross-validation to standard deviation equal to 1.98. Based on this value, the calibration equation was used to establish an LF indicator trait (predicted LF; pLF) on a large number of milk samples (n = 7,690). A subsequent study of its variability was conducted, which confirmed that stage of lactation and lactation number influence the overall pLF level. Small differences in mean pLF among 7 dairy breeds were also observed. The pLF content of Jersey milk was significantly higher than that in Holstein milk. Therefore, the choice of breed could change the expected LF level. Heritability estimated for pLF was 19.7%. The genetic and phenotypic correlations between somatic cell score and pLF were 0.04 and 0.26, respectively. As somatic cell score increases in presence of mastitis, this observation seems to indicate that pLF, or a function of observed pLF, compared with expected LF might have potential as an indicator of mastitis. The negative genetic correlation (−0.36) between milk yield and pLF could indicate an undesirable effect of selection for high milk production on the overall LF level. [less ▲]

Mapping of the bovine growth hormone secretagogue receptor (GHS-R) and polymorphism study in cattle

Poster (2006, December)

A third control pathway of the Growth Hormone (GH) secretion has come into picture since the development of synthetic compounds known as Growth Hormone Secretagogues (GHSs). The GHS Receptor (GHS-R) and ... [more ▼]

A third control pathway of the Growth Hormone (GH) secretion has come into picture since the development of synthetic compounds known as Growth Hormone Secretagogues (GHSs). The GHS Receptor (GHS-R) and its subtype are abundantly located in the hypothalamus-pituitary unit, but are also distributed in other central areas and peripheral tissues. The GHS-R belongs to the G-protein coupled receptor family with seven transmembrane domain architecture. In order to determine the GHS-R gene sequence, total mRNA was extracted from abomasum and two types of GHS-R cDNA were identified. These two types are transcript variants (1a and 1b) of the same GHS-R gene. The gene encompasses two exons and a single intron. Using a 3000 Rad hybrid panel, the GHS-R gene was mapped to Bos taurus autosome 1 (BTA 1). This localization on BTA 1 agrees totally with comparative data between cattle and human since BTA 1 corresponds to part of human chromosome 3 where human GHSR is also mapped. By two-point analysis, most significantly linked marker are BL26 and BMS4031 (both LOD score : 5,66). Some studies detected different QTLs near these markers like for growth rate, carcass yield, milk portein and milk yield. In the cattle industry, it is of economical importance to increase plasma GH secretion because it is associated with faster growth, less fat stores and improved milk production. Being of economical importance and the detected QTLs near the GHS-R gene, it would be interesting to study the polymorphism on the bovine GHS-R gene. Screening for polymorphisms in the two exons on ten Belgian Blue bulls, ten Holsteins bulls and ten Limousin bulls revealed a total of four single nucleotide polymorphisms (SNPs): three SNPs are in the first exon and one SNP in the second exon. In order to evaluate if GHS-R could be involved in genetic variation for growth rate, carcass yield, milk portein and milk yield, an association study between SNPs on GHS-R gene and these traits could be performed in a major cattle population. [less ▲]

Mapping and polymorphism of bovine ghreline gene

Poster (2006, August)

Bovine ghrelin, a 27-amino-acid peptide has been identified in bovine oxyntic glands of the abomasum. It is an endogenous growth hormone secretagogue. Total mRNA was extracted from abomasum and complete ... [more ▼]

Bovine ghrelin, a 27-amino-acid peptide has been identified in bovine oxyntic glands of the abomasum. It is an endogenous growth hormone secretagogue. Total mRNA was extracted from abomasum and complete ghrelin mRNA was sequenced by rapid amplification of cDNA ends. The gene contains five exons and four introns with a short noncoding first exon of 17 bp similar to mouse and human ghrelin gene. Using a radiation hybrid panel, the gene was mapped to chromosome 22 near microsatellite markers UWCA49, BM4102, BMS1932, BM2613 and URB035 with good LOD Score. Some studies detected different QTLs near these markers like for milk fat percent, milk protein percent and somatic cell score. So, it would be interesting to study the polymorphism on the bovine ghrelin gene. Screening for polymorphisms in the five exons and the introns II and IV on ten Belgian Blue bulls, ten Holsteins bulls and ten Limousin bulls revealed a total of three single nucleotide polymorphisms. In order to evaluate if ghrelin could be involved in genetic variation for milk fat percent, milk protein percent and somatic cell score an association study between SNPs on ghrelin gene and these traits could be performed in a major cattle population. [less ▲]

Identification and characterization of four splicing variants of ovine POUF1 gene

in Gene (2006), 382

Effets pré- et/ou probiotiques de levure métabolisant des ions minéraux sur les performances et fonctions immunes

Report (2006)

Contribution de la biologie moléculaire au progrès de l'élevage.

Conference (2005, January 26)

Approches méthodologiques de détection et d'utilisation d'informations moléculaires dans l'amélioration génétique de la fertilité chez les bovins.

Report (2005)

Validation Of A Heterologous Radioimmunoassay For Insulin-Like Growth Factor-I In Camels

in Journal of Camel Practice and Research (2005), 12(2),

Effets pré- et/ou probiotiques de levure métabolisant des ions minéraux sur les performances et fonctions immunes d’animaux de rente

Report (2004)

VEGF Concentrations Levels in Bovine Ovulatory Follicles after Prostaglandin Treatment

in Journal of animal and veterinary advances (2004), 3