English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

Recently, functional traits are of interest to dairy cattle breeders as their breeding goals consist of milk production traits as well as functional traits (FT). Thus, the main objective of the present study was to estimate (co)variance components, genetic and phenotypic parameters of functional traits and their associations with milk production trait. There were 3674 records collected from 1230 cows, daughters of 160 sires and 857 dams of a Friesian herd raised at Sakha experimental farm belonging to Animal Production Research Institute (APRI) in Egypt. Analyzing 305-day milk yield (M305) with FT (retained placenta (RP), stillbirth (SB), gestation length (GL) and days open (DO)) was carried out using two types of models. Bivariate threshold repeatability animal models were used to analyze binary functional traits (RP and SB) with M305 and other continuous FT (GL and DO). Bivariate Linear repeatability animal models were used to analyze continuous traits: M305, GL and DO. Estimates of heritability (h) ranged between 0.19 to 0.24 for M305; from 0.23 to 0.26 for RP; from 0.18 to 0.32 for SB; 0.07 for GL and around 0.01 for DO. The corresponding repeatability (t) estimates for M305 was 0.39; from 0.45 to 0.53 for RP; 0.99 for SB; from 0.08 to 0.11 for GL and from 0.01 to 0.26 for DO, respectively. Moderate h and high t estimates of SB with antagonistic moderate genetic correlations (rG) with M305 in addition to the moderate positive rG with both of GL and DO suggest that genetic improvement can be achieved for M305 and against SB occurrences through direct selection than indirect selection. Moreover, moderate h estimates of RP with positive rG with reproductive traits (GL and DO) were desirable in the sense that direct selection for minimizing the incidence and the risks of RP would result in progress of selection response against extended or prolonging both DO and GL in subsequent lactations. Selecting cows that have more milk could decrease SB cases in later lactations, but should be done with caution due to the unfavorable moderate rG between M305 and DO. Moderate positive rG estimates between GL and both of RP and SB emphasized that GL were genetically associated with SB and RP incidences.

ASSOCIATIONS BETWEEN FUNCTIONAL TRAITS AND MILK PRODUCTION IN FRIESIAN CATTLE USING THRESHOLD AND LINEAR MODELS.