the aim of this study was to estimate genetic parameters of age at first calving and its relationship with productive traits of holstein dairy cows. a total of 24491 first lactation records (2x 305d) which were collected from 1995 to 2009 were used. the general linear model (glm) procedure was applied to determine effective factors on studied traits. herd-year-season (hys) and age at first calv...

The main objective of the study was to identify and analyze the inefficiency and yield gaps of wheat production in Bangladesh. The study employed farm level cross sectional data from three major wheat growing areas of Bangladesh. Yield of wheat was found to vary across locations and farm categories. The average technical inefficiency of wheat production in Bangladesh is 16. This indicates a goo...

Structural steel sections are mainly used in beams and columns of building frames. Iran National Steel IndustrialGroup is among the oldest and largest producers of beams in Iran. It has two beam production lines, namely Line630 and Line 650. In this study, the mechanical properties of manufactured beams in these production lines werecompared. Based on the t-test results, the e...

abstract different strategies are existed for adjusting with water shortage, of which the strategy of suitable policies adoption by determining optimum production function can be mentioned. water shortage and quality degradation of soil and water resources is one of main factors of production reduction. therefore, this study was carried out for determination of tomato sensitivity coefficients a...

BACKGROUND 3-hydroxypropionic acid (3-HP) is an important platform for the production of C3 chemicals, including acrylic acid, methyl acrylate, and acrylamide. Microbial production of 3-HP is mainly due to glycerol metabolism. In this study, in order to improve microbial 3-HP production, we applied a metabolic toggle switch for controlling the glycerol metabolism to redirect the excess metaboli...

【Objective】 In order to quantify the yield formation of protected tomato, 【Method】 the field experiments on varieties and fertilizer were conducted in 2009 and 2010, and cultivars: (B1) American mole 1 (early maturing), (B2) Chaoshijifanqiedawang (late maturing), and (B3) American 903 (medium maturing) were adopted; The models of dry matter production and yield formation for protected tomato we...

abstract the quantative and qualitative yield comparison of three cucumber f1 cultivars including' sina, amyral, and negin was evaluated using 3×3×3 factorial experimental design with six replication. three types of pruning treatments were applied; cutting down all branches on main stem (b1), leaving one node and the leaf next to it on all branches (b2), leaving two node and the leaf next to th...

abstract             (co) variance components of milk, fat and protein yield of 11368 first lactation iranian holstein dairy cow were estimated by single trait random regression test-day models and restricted maximum likelihood (reml) method. in this study the homogeneous residual variance was assumed throughout lactation. estimated heritability for 305-day production traits ranged from 0.25 to...