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...

Each stage (early, middle and late) of lactation is a critical period during which maternalmalnutritional can negatively effects on the offspring's body development. We investigatedthe maternal high fat diet (HF) different stages bodyweight male offspring at weaning. Female Wistar rats were fed either HF only duringthe first week (HF1-7 group), second (HF7-14 third (HF14-21 group) andth...

To analyze the effects of some environmental factors such as herd, year, season of calving, stage of lactation on mastitis incidence, a total of 101147 monthly test day somatic cell counts collected from 13977 Iranian Holstein heifers calved between 2002 and 2006 in 183 herds were used. The event of mastitis in cows was coded as 1 if their somatic cell count at specific test day was greater tha...

Genetic parameters and relative breeding values were estimated for milking speed of US Brown Swiss dairy cattle. Owner-recorded milking-speed scores on a scale of 1 (slow) to 8 (fast) were collected by the Brown Swiss Association as part of its linear type appraisal program starting in 2004. Data were 7,366 records for 6,666 cows in 393 herds. The pedigree file included information for 21,458 a...

The economical profitability of the dairy industry is based on the quality of the bulk milk collected in the farms, therefore it was based on the herd level rather than on the individual animals at real time. Udder infection and stage of lactation are directly related to the quality of milk produced on the herd level. However, improvement of milk quality requires testing each animal's milk sepa...

Two experiments were conducted with the aim of studying how dietary fat source, reproductive stage (Exp. 1), and diurnal variation (Exp. 2) affect plasma ketone bodies in sows. In Exp. 1, 40 second-parity sows were fed 1 of 5 lactation diets from 7 d prepartum until 28 d postpartum, with low or high levels (3% or 8%) of dietary fats with different proportions of medium- and long-chain fatty aci...

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...

Hirosaki hairless rat (HHR) is a mutant strain spontaneously derived from Sprague-Dawley rats (SDR), and its inheritance is autosomal recessive. In addition to hair loss, female HHRs show involution of the mammary gland at an early stage of lactation. In the present study we investigated the mammary gland development in HHR. Morphological examinations revealed that HHR mammary glands are underd...

THE action of extracts of various organs, especially that of the pituitary gland (hypophysin) upon milk secretion has been frequently investigated. The results of these investigations have been summarised by Hammond [1913], who made an extensive study of the action of hypophysin upon the milk flow in the goat. He found that there was an immediate action and that the effect soon passed off, and ...

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...