in order to examine the effect of using rumen protected methionine (mepron, evonik industries, hanau, germany) on productive and reproductive performance under field condition, 195 holstein cows were used in a unbalanced completely randomized design and 2 groups. experimental treatments consisted of: 1) control group with 110 holstein dairy cows (71±51 dim and 47.5±12 milk yield) and without me...

The objective of the study was to examine how the fatty acid composition of milk especially concentrations of conjugated linoleic acids (CLA) and trans-C18:1 isomers and milk fat percentage were affected by silage type and concentrate level. Forty dairy cows were blocked and randomly assigned to one of four diets in a 2 x 2 factorial arrangement of treatments and a six week experimental period....

abcg2 (atp binding cassette subfamily g member 2) gene, located on chromosome 6 encodes the abcg2 protein that transports various xenobiotics, cytostatic drugs across the plasma membrane as well as cholesterol into milk. a single nucleotide change (a/c) in base 86 of exon 14 is capable of encoding a substitution of tyrosine with serine in the abcg2 gene and increase milk yield while decreasing ...

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...

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...