Search results for "Test-Day Model"
showing 2 items of 2 documents
Trend in dairy sheep BLG genotype found with repeatability test-day model.
2007
A total of 19.207 test-days, collected on 4 farms from 1999-2006 and belonging to 1109 Valle del Belice dairy sheep were analyzed with a repeatability model. After strict outlier analysis 17.747 records were retained. Animals were reared in an extensive system resulting in large environmental influences. However, significant genetic variation was detected in production traits (milk production mean=1336 stdg=93 g/d, fat+protein 167 stdg=12 g/d). Heritability was only 3% while the interaction year by month of test-day explained 27% of the variation. A protein and DNA analysis program was initiated in order to facilitate selection to maintain these flocks under these conditions. In total 427 a…
Test-Day Model Heritabilities for somatic cvell score and production traits in primiparous Valle del Belice sheep
2006
A repeatability test-day animal model was used to investigate heritabilities of somatic cell score (SCS) and milk production traits in Valle del Belice sheep. The heritability estimate for SCS falls within the range reported in literature (0.14±0.03), while estimates for milk production and composition traits were below those obtained by others, 0.12±0.03, 0.09±0.02, 0.14±0.03, 0.14±0.03, and 0.12±0.03, respectively, for milk yield, fat %, fat yield, protein %, and protein yield. Flock-test-day had a substantial effect on milk production traits but not on SCS. These results provide the basic parameters required for discussion of selection strategies and objectives in Valle del Belice sheep.