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...

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...

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) ...

An understanding of the mechanisms regulating milk yield in sows is crucial for producers to make the best management decisions during lactation. Suckling of mammary glands by piglets is one factor that is essential for development of these glands during lactation and for the maintenance of lactation in sows. The process of mammary development is not static as the majority of it takes place in ...

Migration of neutrophils into mammary tissue provides the first immunological line of defense against bacteria that penetrate the physical barrier of the teat canal. Evasion of neutrophil defenses provides an opportunity for invading bacteria to become established. Depletion of neutrophils results in a dramatic increase in susceptibility to intramammary infection. Numerous cytoplasmic particles...

BACKGROUND Drinking alcohol during pregnancy can cause many birth defects and developmental disabilities. There is considerable information available for pregnant women regarding the dangers of drinking alcohol during this time. Postpartum many women enter the period of lactation, which can last for several months to years. However information regarding safe levels of alcohol consumption during...

Twenty one multiparous, nonpregnant, lactating dairy cows were used to assess the impact of stage of lactation on visceral tissue mass and small intestinal cell proliferation. Cows were slaughtered at each of 4 stages of lactation: 14, 90, 120, and 240 d of lactation. With stage of lactation, DMI increased through d 90 and thereafter remained similar through d 240 (quadratic). Carcass weight an...

The maintenance energy required to sustain the cow herd is a major cost of beef production. This work proposes modifying parameter estimates for a population-specific lactation curve with genetic evaluations for the maternal genetic effect on calf gain from birth to weaning to provide inputs for a commonly used prediction of energy requirement. Daily milk production (y) was modeled as a functio...