In this study test-day records of milk (kg), fat (g), and protein (g) yields, somatic cell score (SCS, cells/ML) collected by Animal Breeding Center of Iran during 2007 and 2009 were used to estimate genetic parameters using random regression model. Models with different order of Legendre polynomials were compared using Bayesian information criterion (BIC).For milk, fat yield and SCS genetic an...

genetic trend for production traits were estimated in iranian holstein cattle using the first lactation data recorded by cattle breeding and dairy product improvement center of the state from 1991 to 2006. effect of some factors on genetic trend was investigated using data from 18 large herds. (co) variance components and genetic parameters were estimated, using five trait animal model and em-a...

some factors affecting crude protein balance (cpb), as a measure of efficiency, were studied using 2824 records of 501 lactating holstein cows. the cpb (kg d-1) was calculated as crude protein (cp) intake (kg) minus cp yield (kg). two different statistical methods including principal components (pcs) and general linear model analyses were used to study the effects of different factors. crude pr...

dairy cattle breeding programs have been based in the selection for traits related to milk production. in this research a data set of 63 herds of east azerbaijan province holstein cattle, collected during 2002-2013 by the iranian animal breeding center was used to estimate the repeatability and heritability of three traits of economic importance. genetic parameters for first three lactations of...

this study was aimed to determine the effects of different dietary levels of methionine and protein on the growth performance and carcass characteristics of broiler chickens. a total of 240 broiler chicks were distributed into a completely randomized design with a 2 × 3 factorial arrangement. experimental factors were: two levels of protein (20% or 24% for starter and 18% or 22% for grower), an...

. eight holstein cows in early lactating stage were used in a 4×4 change-over design within 4 periods of 21-d to determine the effects of alfalfa hay particle size and soybean oil supplementation on intake, digestibility, ruminal and blood metabolites, chewing activity, milk yield and compositions. four total mixed rations containing 20, 20 and 60% corn silage, alfalfa hay and concentrate respe...