Search results for "mixed model"

Relationship between inbreeding and milk production traits in two Italian dairy sheep breeds.

2022

The effects of inbreeding in livestock species breeds have been well documented and they have a negative impact on profitability. The objective of this study was to evaluate the levels of inbreeding in Sarda (SAR, n = 785) and Valle del Belice (VdB, n = 473) dairy sheep breeds and their impact on milk production traits. Two inbreeding coefficients (F) were estimated: using pedigree (FPED), or runs of homozygosity (ROH; FROH) at different minimum ROH lengths and different ROH classes. After the quality control, 38,779 single nucleotide polymorphisms remained for further analyses. A mixed-linear model was used to evaluate the impact of inbreeding coefficients on production traits within each …

Modelling the relationship between sexual reproduction and rhizome growth in Posidonia oceanica (L.) Delile

2006

The relationship between flowering and growth performance of Posidonia oceanica (L.) Delile in meadows distributed along the south-eastern coast of Sicily (Italy) was investigated by means of a statistical model (generalized linear mixed model) combined with the lepidochronological analysis. Over a 28-year period, 67 floral stalk remains were observed. The highest flowering index was recorded in lepidochronological year 1998 (10.1%) and the Inflorescence Frequency per age showed a clear decrease corresponding to 15-year-old shoots. The sexual reproductive event had positive effects on rhizome elongation (cm year−1) and leaf production (no. leaves year−1) in the same flowering year, whilst n…

Small area estimation with linear mixed models from unit-level panel and rotating panel data

2009