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Although vitrification is the current method of choice for oocyte and embryo cryopreservation, it may have detrimental effects on reduction–oxidation status and mitochondrial activity. The aim of this study was to evaluate the effect of supplementing invitro culture (IVC) media and/or vitrification solutions with the antioxidant resveratrol on active mitochondria, mitochondrial superoxide production and lipid peroxidation. Abattoir-derived oocytes were matured and fertilised invitro using standard procedures. Following IVF (21h later), zygotes were cultured in IVC medium supplemented with 0 or 0.5µM resveratrol. On Day 7, blastocysts were vitrified using the Cryotech Vitrification Kit (Cryo Tech Laboratory) with or without 0.5µM resveratrol. After warming, active mitochondria, mitochondrial superoxide production and lipid peroxidation were evaluated using Mito Tracker Green FM, MitoSOX Red and BODIPY581/591 C11 staining respectively. The vitrification–warming process significantly increased active mitochondria and mitochondrial superoxide production in bovine embryos (P<0.05, ANOVA). The addition of 0.5µM resveratrol to the IVC medium or vitrification solutions significantly attenuated the increase in active mitochondria (P<0.05), but not in mitochondrial superoxide production, whereas embryos cultured and vitrified with resveratrol showed the highest values for both parameters (P<0.05). Regarding lipid peroxidation, no significant differences were detected between treatments. In conclusion, resveratrol supplementation of IVC medium or vitrification solutions contributes to recovery of an embryo’s ‘quieter’ state (i.e. lower oxidative metabolism) after vitrification. However, supplementation of both solutions with resveratrol seemed to have a pro-oxidant effect.

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The objective of this research was to estimate the phenotypic association between some conformation traits and dairy traits in the Antioquia Holstein dairy cattle. To achieve this, 8037 records from 139 herds located in the department of Antioquia, Colombia were analyzed. Data were obtained from a control program performed between 2008 and 2011. The phenotypic association was carried out through three different statistical analyzes: a generalized linear model, a regression analysis and the Pearson correlation coefficient. It was found that the main linear traits associated with productive traits were body compound (index comprised by stature, chest width, angularity, and rump angle) and udder compound (index comprised by udder depth, fore udder attachment, rear udder height, rear udder width, central ligament, front teat position and rear teat position) fore udder attachment, teat length, rear teat position and udder depth. The highest regression coefficient was for milk yield on udder compound (510.67 l/lac); the lowest was for fat percentage on udder depth (0.028%). The highest correlation was between milk yield and udder depth (-0.21), and the lowest was between fat percentage and front teat position (0.00). These results indicate that the phenotypic association between conformation traits and productive parameters tends to be low. This is the reason why it is important to estimate genetic correlations and to determinate their importance and possible use in genetic improvement programs.

Because FSH and its receptor play a fundamental role in reproduction, the objective of this research was determining the effect of the A-320T polymorphism in productive and reproductive traits in Antioquia Holstein cows. The PCR-RFLP was used to amplify a segment of 970 bp of the bovine follicle stimulating hormone receptor gene (FSHR) which was digested with the restriction enzyme TaqI. The effect of the FSHR genotypes on productive and reproductive traits was determinate by a Mixed Linear Model and Tukey Test was used to establish significant differences between means for the three genotypes. The effect of allelic substitution was studied through a linear regression model where the genotypes AA, AT and TT were transformed into a quantitative scale of 0, 1 and 2, respectively according to the number of possessed T alleles. In Antioquia Holstein cattle the most common genotype was the AT (0.485) followed by TT (0.417) and AA (0.096) genotypes. Allele frequencies were 0.339 for A and 0.660 for T, respectively. The FSHR genotypes did not exert a significant effect on the principal productive parameters, except for fat percentage (P<0.01) where the TT individuals presented the highest percent. Results showed that T allele seems to improve the solids in milk while A allele improves dairy yield. The reproductive parameters were not affected by this SNP but AT animals showed a higher number of services per conception. Further studies are required to determine whether this SNP may be used as a molecular marker.