Association of polymorphisms in the IGF-I, GHR and STAT5A genes with serum IGF-I concentration and reproductive performance of Holstein dairy cows.

This study was conducted to evaluate associations of polymorphisms in the genes for the growth hormone receptor (GHR), insulin-like growth factor I (IGF-I) and signal transducer and activator of transcription 5A (STAT5A) with serum concentrations of IGF-I, reproductive performance and milk production of postpartum Holstein dairy cows. Days from calving to first ovulation (DTO) and calving to conception interval (CCI) were evaluated in 95 Holstein cows. Serum concentrations of IGF-I and β-hydroxybutyrate (BHBA) were quantified in samples collected in sequential blood collections.

Intrafollicular paraoxonase 1 activity and the steroidogenic potential of the first post-partum dominant follicle in dairy cows.

Cows experiencing high levels of inflammation and specific metabolic conditions tend to have slower follicular growth and lower serum and follicular concentrations of oestradiol (E2). Paraoxonase1 (PON1) activity decreases during inflammatory processes. Therefore, the aim of this study was to evaluate the association between serum and intrafollicular (FF) PON1 activity and the serum and intrafollicular levels of E2 and progesterone (P4), as well as the mRNA expression of genes related to steroidogenesis, metabolism and inflammation in the first post-partum dominant follicle of Holstein cows.

Polymorphisms in the anti-oxidant paraoxonase-1 (PON1) gene associated with fertility of postpartum dairy cows.

Paraoxonase 1 (PON1) is a negative acute phase plasma protein synthesized by the liver that has anti-oxidant activity. The aim of this study was to evaluate the association of single nucleotide polymorphisms (SNPs) in the PON1 promoter region with plasma PON1 activity and fertility in Holstein dairy cows. Sixty-eighty Holstein cows were used in this initial investigative study.

The acute effect of intravenous lipopolysaccharide injection on serum and intrafollicular HDL components and gene expression in granulosa cells of the bovine dominant follicle.

The aim of this study was to evaluate the effect of an acute systemic inflammatory response induced by lipopolysaccharide (LPS) in the serum and follicular fluid (FF) high-density lipoprotein (HDL) components, hormone concentrations and granulosa cell gene expression. For this purpose, twenty non-lactating Jersey dairy cows were submitted to a progesterone (P4) - estradiol (E2) based synchronization protocol. Cows received a single i.