________________________________________________________________________________ Abstract The effect of inbreeding on the 305-d yields of milk, fat and protein, and the percentages of fat and protein in the first three lactations was estimated using records on the South African Jersey cows that participated in the National Dairy Animal Improvement Scheme. Inbreeding coefficients were estimated ...

in order to evaluation of genotype by environment interactions in holstein cows, iran was divided into cold, middle cold, temperate and hot climate regions. for this purpose used from 39570, 35813 and 18955 records for milk, fat and protein yields, respectively, to progeny test for 35 sires that have 50 daughters in each climate. the data were collected by the centre of breeding and improvement...

This study set out to demonstrate the feasibility of merging data from different experimental resource dairy populations for joint genetic analyses. Data from four experimental herds located in three different countries (Scotland, Ireland and the Netherlands) were used for this purpose. Animals were first lactation Holstein cows that participated in ongoing or previously completed selection and...

________________________________________________________________________________ Abstract Artificial neural networks (ANNs) have been shown to be a powerful tool for system modelling in a wide range of applications. In this paper, we focus on the capability of ANNs to predict 305-d milk yield in early lactation of Brown Swiss cattle, based on a few test-day records, and some environmental facto...

Genomic selection has been widely implemented in many livestock breeding programs, but it remains incipient buffalo. Therefore, this study aimed to (1) estimate variance components incorporating genomic information Murrah buffalo; (2) evaluate the performance of prediction for milk-related traits using single- and multitrait random regression models (RRM) single-step best linear unbiased approa...

Six groups of Sahiwal-Friesian crossbred cows, namely M50-1, M50-2, M50-3, M56, M63 and M75-1 were evaluated. In total 180 cows were used and milk collected was evaluated for composition and quality. The effect of genotypes was significant (P≤0.05) only for titrable acidity (TA) and milk yield (MY). The M50-1 had the highest milk yield per day (8.73 ± 1.65 kg) but this was not significantly dif...

Using spline functions (segmented polynomials) in regression models requires the knowledge of the location of the knots. Knots are the points at which independent linear segments are connected. Optimal positions of knots for linear splines of different orders were determined in this study for different scenarios, using existing estimates of covariance functions and an optimization algorithm. Th...

A dynamic programming model was developed in which cows were described in terms of lactation number, body weight, 305-day milk yield, and milk fat percent. Milk returns, beef sales, feed costs, replacement costs, and cow depreciation costs were included. A 10-yr planning horizon was used. Three prices were assigned to each economic component and to the interest rate in the discounting procedure...