Analysis of culling records and estimation of genetic parameters for longevity and some production traits in Holstein dairy cattle

<p>We used data collected on 48,739 cows from 1982 to 2013 from Foka farm in the Isfahan province of Iran to assess the reasons for culling in Iranian Holstein dairy cattle in the context of breeding values of economic traits, and also to study the relationship between longevity and production traits. Estimation of (co)variance components and genetic parameters for studied traits including MY, FY, herd life (HL) and length of production life (LPL) was by AI-REML algorithm in WOMBAT software. The results showed that 27.11% of cows were culled voluntarily under the farmers’ command. The number and reasons for culling animals varied considerably over the years. Also, the results showed that involuntarily culled animals were valuable with significantly higher breeding values for MY and FY (<i>P</i> < .0001) than those of voluntarily culled individuals. The estimates of heritability for longevity traits (HL and LPL) were low (0.11 and 0.09), but their genetic correlation with production traits were high and positive (0.63–0.70). Our results suggest that some opportunity may exist for genetic improvements in fat and milk yield in Iranian Holsteins.</p

Image_2_Isoprenoid biosynthesis regulation in poplars by methylerythritol phosphate and mevalonic acid pathways.TIF

It is critical to develop plant isoprenoid production when dealing with human-demanded industries such as flavoring, aroma, pigment, pharmaceuticals, and biomass used for biofuels. The methylerythritol phosphate (MEP) and mevalonic acid (MVA) plant pathways contribute to the dynamic production of isoprenoid compounds. Still, the cross-talk between MVA and MEP in isoprenoid biosynthesis is not quite recognized. Regarding the rate-limiting steps in the MEP pathway through catalyzing 1-deoxy-D-xylulose5-phosphate synthase and 1-deoxy-D-xylulose5-phosphate reductoisomerase (DXR) and also the rate-limiting step in the MVA pathway through catalyzing 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), the characterization and function of HMGR from Populus trichocarpa (PtHMGR) were analyzed. The results indicated that PtHMGR overexpressors (OEs) displayed various MEP and MVA-related gene expressions compared to NT poplars. The overexpression of PtDXR upregulated MEP-related genes and downregulated MVA-related genes. The overexpression of PtDXR and PtHMGR affected the isoprenoid production involved in both MVA and MEP pathways. Here, results illustrated that the PtHMGR and PtDXR play significant roles in regulating MEP and MVA-related genes and derived isoprenoids. This study clarifies cross-talk between MVA and MEP pathways. It demonstrates the key functions of HMGR and DXR in this cross-talk, which significantly contribute to regulate isoprenoid biosynthesis in poplars.</p

Table_1_Isoprenoid biosynthesis regulation in poplars by methylerythritol phosphate and mevalonic acid pathways.XLS

It is critical to develop plant isoprenoid production when dealing with human-demanded industries such as flavoring, aroma, pigment, pharmaceuticals, and biomass used for biofuels. The methylerythritol phosphate (MEP) and mevalonic acid (MVA) plant pathways contribute to the dynamic production of isoprenoid compounds. Still, the cross-talk between MVA and MEP in isoprenoid biosynthesis is not quite recognized. Regarding the rate-limiting steps in the MEP pathway through catalyzing 1-deoxy-D-xylulose5-phosphate synthase and 1-deoxy-D-xylulose5-phosphate reductoisomerase (DXR) and also the rate-limiting step in the MVA pathway through catalyzing 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), the characterization and function of HMGR from Populus trichocarpa (PtHMGR) were analyzed. The results indicated that PtHMGR overexpressors (OEs) displayed various MEP and MVA-related gene expressions compared to NT poplars. The overexpression of PtDXR upregulated MEP-related genes and downregulated MVA-related genes. The overexpression of PtDXR and PtHMGR affected the isoprenoid production involved in both MVA and MEP pathways. Here, results illustrated that the PtHMGR and PtDXR play significant roles in regulating MEP and MVA-related genes and derived isoprenoids. This study clarifies cross-talk between MVA and MEP pathways. It demonstrates the key functions of HMGR and DXR in this cross-talk, which significantly contribute to regulate isoprenoid biosynthesis in poplars.</p