the fixed regression test-day model (frm) and random regression test-day model (rrm) for genetic evaluation of milk yield trait of dairy cattle in khorasan razavi province were studied. breeding values and genetic parameters of milk yield trait from two models were compared. a total of 164391 monthly test day milk records (three times milking per day) obtained from 19217 holstein cows distribut...

Most studies on the factors limiting sustained energy intake (SusEI) during peak lactation period have been performed in females at the 1st lactation event. However, an inconsistent change in SusEI is observed between the 1st and 2nd lactation event. Thus, the limits to SusEI may be associated with reproductive experiences, but the effects of reproductive experiences on SusEI or reproductive ou...

Daily milk records of 88 cows in a multibreed dairy herd were used to describe lactation curves and test the ability of seven models to predict daily milk yields, and accumulated 100-d and 305-d milk yields. The seven mathematical models were a gamma function, a mixed log second-degree polynomial model, and five polynomial regression models. Cows were of three breed groups: Holstein Friesian (H...

In this research, 272977 test day records collected from 659 herds during years 2001 to 2011 by the Iranian animal breeding center were used. In the first section the ability of different models to predict daily milk yield from alternative milk recording was tested. The result showed that a complex model including noon milking time plus the effect of lactation curve of Ali and Schaeffer functio...

The objective of the current study was to evaluate the effect of bovine somatotropin (bST) on milk yield and composition of Holstein cows in early and very early lactations. Twenty-two lactating Holstein cows averaging 62 days in milk (DIM:25-115), 28.5 kg/d milk, a body condition score (BCS) of 2.87, and 648.2 kg of body weight (BW), were assigned to one of the four treatments in a completely ...

In Italy, the interest for jennet milk production has recently developed. An 18-month-long experiment was carried out on a jennet farm near Milo (CT), where 24 jennets, which derived from the Ragusana breed, were tested for milk yield and composition over an entire lactation period. The jennets were fed with hay and concentrate in a large paddock. From the 28th post-foaling day to the end of th...

The aim of the study was to determine the effect of age of cows, i.e. subsequent lactation and stage of lactation, on bioactive whey protein content in milk of dairy cows of six primary breeds kept in Poland. In all cases the significant correlations between lactoferrin concentration in milk and stage of lactation was stated. Its content gradually increased with the course of lactation but the ...

The lactating tammar wallaby progressively alters the rate of secretion and composition of its milk to provide appropriate nutrition for the developing offspring, whose needs are signalled by changes in the pattern and efficiency of its sucking. Tammars are also capable of asynchronous concurrent lactation, when the mother provides a dilute milk for a newborn young permanently attached to the t...

During lactation, highly specialized secretory mammary epithelial cells (MECs) produce and secrete huge quantities of nutrients and nonnutritive factors into breast milk. The zinc (Zn) transporter ZnT4 (SLC30A4) transports Zn into the trans-Golgi apparatus for lactose synthesis, and across the apical cell membrane for efflux from MECs into milk. This is consistent with observations in "lethal m...

Production of milk is a key characteristic of mammals, but the features of lactation vary greatly between monotreme, marsupial and eutherian mammals. Marsupials have a short gestation followed by a long lactation period, and milk constituents vary greatly across lactation. Marsupials are born immunologically naïve and rely on their mother's milk for immunological protection. Koalas (Phascolarct...