Random regression models (RRM) are used for genetic estimations of milk traits in dairy cows. RRM utilize data on traits that are repeated during the time, such as milk trait, which allows of the evaluation of the test day production information. In this study, to estimate genetic parameters for milk production trait, test day records (TDR) were collected from the first lactation of Holstein co...

To examine the effect of including oil in diets on early lactating productive performance parameters including; dry matter intake, milk production and components, body condition score, body weight and negative energy balance; twenty multiparous Holstein cows were randomly assigned to the experimental diets from 21 days before predicted calving time to 50 days in milk. Treatments including 1) co...

The aim of this study was to evaluate the effects of balancing low protein diets for methionine and lysine on performance of early lactation Holstein cows under hot environmental temperature. Twenty one multiparous Holstein cows in early lactation were allocated to three experimental rations including, 1) High protein ration with 17.5% CP, 2) Medium protein ration with 16% CP and 12 g/d rumen p...

this study was carried out to investigate the relationship between early lactation curve parameters andcalving interval in holstein cows of iran. in order to describe the lactation curve, the incomplete gammafunction was fitted to 5,754,428 test-day milk records corresponding to 766,108 lactations on 315,634 cowsin 2,448 herds. cows with higher milk yield during early lactation had shorter calv...

random regression models (rrm) are used for genetic estimations of milk traits in dairy cows. rrm utilize data on traits that are repeated during the time, such as milk trait, which allows of the evaluation of the test day production information. in this study, to estimate genetic parameters for milk production trait, test day records (tdr) were collected from the first lactation of holstein co...

the objective of this study was to investigate the effect of principal components (pc) of the regression coefficients (co)variance matrix on the lactation curve, and on the formation of selection index to modify the curve, based on these pc’s, and as well to estimate additive genetic and phenotypic variances and heritability of the constructed selection index. lactation period of 301 d (5-305) ...

this experiment was performed to investigate whether feeding xylose-treated soybean meal (xsbm) or corn gluten meal (cgm) is economically better under field conditions. ninety-four multiparous early lactating holstein cows (55±5 days in milk and 2.82±0.41 body condition score) were used in a completely randomized design. cows were randomly assigned to one of two treatments: xsbm or cgm as the m...

A comparison of conserving timothy/meadow fescue/meadow grass as silage or hay was conducted with Finnish Landrace ewes. Intake of hay (H), silage (S) and hay/silage (HS), and the performance of 30 Finnish Landrace ewes carrying twins, triplets and quadruplets and suckling either twin or triplet lambs was measured during the last 8 weeks of pregnancy and during the first 6 weeks of lactation. T...

the objective of this study was to evaluate the effects of supplementation of different level protein diets with rumen protected methionine and lysine on performance and ruminal parameters in holstein dairy cows when in their early lactation. twenty one dairy cows in their early lactations were assigned to three treatments in a randomized block design experiment of a 35-d duration period. diets...

the aim of this study was to evaluate the effects of balancing low protein diets for methionine and lysine on performance of early lactation holstein cows under hot environmental temperature. twenty one multiparous holstein cows in early lactation were allocated to three experimental rations including, 1) high protein ration with 17.5% cp, 2) medium protein ration with 16% cp and 12 g/d rumen p...