description of lactation curve were investigated using sine function, compare it with two functions (dijekstra and wood). the data contained 32233 dairy milk yield records from 93 first parity iranian holstein cows that had calving between aug. 2008 and jul. 2009. actual milk production per day and subsequently the actual production of each animal were available in the first lactation. lactatio...

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) ...

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...

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...

test day milk records of a holstein dairy farm collected during years 2004 to 2006 on 142 cows in the 1st lactation vs. 140 cows in the 2nd lactation were used in this research. there were real milk yields of cows available in each part of lactation in this farm making it possible to compare functions based on the new criteria (squared error of estimation). five functions were compared to estim...

Breast cells drive bone demineralization during lactation and metastatic cancers. A shared mechanism among these physiological and pathological states is endocrine secretion of parathyroid hormone-related protein (PTHrP), which acts through osteoblasts to stimulate osteoclastic bone demineralization. The regulation of PTHrP has not been accounted for fully by any conventional mammotropic stimul...

Nutrition has a significant effect on reproduction and lactation in Ruminant. Supply of require nutrient of dairy cows and ewes in early lactation is the main challenges that will be considered, since in most cases the animals facing negative energy balance after calving and the beginning of the period of lactation. Negative energy balance may sometimes result in reduced livestock production an...

Nutrition has a significant effect on reproduction and lactation in Ruminant. Supply of require nutrient of dairy cows and ewes in early lactation is the main challenges that will be considered, since in most cases the animals facing negative energy balance after calving and the beginning of the period of lactation. Negative energy balance may sometimes result in reduced livestock production an...

nutrition has a significant effect on reproduction and lactation in ruminant. supply of require nutrient of dairy cows and ewes in early lactation is the main challenges that will be considered, since in most cases the animals facing negative energy balance after calving and the beginning of the period of lactation. negative energy balance may sometimes result in reduced livestock production an...