the objective of this study was to estimates the genetic and environmental components for the lactation curve parameters, milk yield, age at first calving (afc), calving interval (ci) and somatic cell count (scc) in iranian holstein cows. the dataset consisted of 210625 test day records from 25883 cows with milk yield in the first parity recorded from july 2002 to september 2007 in a total of 9...

the genetic parameters for milk production and milk fat traits for first to third parities were estimated using single, multi trait and repeatability models. the genetic parameters for test day milk records were also estimated using random regression model. the test day records and 305 day milk records of 17055 cows from 10 herds collected between years 1996-2007 in khorasan razavi province wer...

Human milk contains an unexpected abundance and diversity of complex oligosaccharides apparently indigestible by the developing infant and instead targeted to its cognate gastrointestinal microbiota. Recent advances in mass spectrometry-based tools have provided a view of the oligosaccharide structures produced in milk across stages of lactation and among human mothers. One postulated function ...

The objective of this study was to estimates the genetic and environmental components for the lactation curve parameters, milk yield, age at first calving (AFC), calving interval (CI) and somatic cell count (SCC) in Iranian Holstein cows. The dataset consisted of 210625 test day records from 25883 cows with milk yield in the first parity recorded from July 2002 to September 2007 in a total of 9...

Lactation is the signature characteristic of mammals wherein the mother nourishes the young by secreting a nutrient-rich milk from her mammary gland. Indeed, naming of the class Mammalia by Linnaeus in 1758 (Linnaeus 1758) emphasizes lactation as the dominant characteristic for the identification of mammals, despite the existence of other anatomical characteristics. This preference reflects the...

The study aimed to determine factors affecting the dry period length and effect of dry days on milk yield, milk composition and lactation length in the next lactation of dairy cows. Data used for analysis included 7264 lactation records collected from 2012 to 2016 on 4737 Holstein cows raised in 152 herds. The statistical model used to determine the factors influencing the dry period length sho...

The evolutionary origin of the mammary gland has been difficult to establish because little knowledge can be gained on the origin of soft tissue organs from fossil evidence. One approach to resolve the origin of lactation has compared the anatomy of existing primitive mammals to skin glands, whilst another has examined the metabolic and molecular synergy between mammary gland development and th...

Three-hour milk production measurements determined by machine milking at 3-d intervals throughout a 63-d lactation period were used to describe lactation curves for crossbred ewes lambing at 1 and 2 yr of age and rearing single and twin lambs. Age of ewe, type of rearing, and day of lactation affected (P < 0.05) milk production. Over the 63-d lactation, average daily milk production was 2.56 an...

We first sought to clarify the effects of discounted rate, survival rate, and lactation persistency as a component trait of the selection index on net merit, defined as the first five lactation milks and herd life (HL) weighted by 1 and 0.389 (currently used in Japan), respectively, in units of genetic standard deviation. Survival rate increased the relative economic importance of later lactati...

Milk production is largely dependent on the shape of the lactation curve. Relevant elements of the lactation pattern are the peak yield, which represents the maximum milk yield during the lactation, and the lactation persistency, which expresses the ability of animals to maintain a reasonably constant milk yield after the lactation peak (Figure 1). Thus, persistent animals are those that show f...