Abstract

ZULKADIR, U.  and  AYTEKIN, İ.. Genetic analysis of test day milk yields of brown swiss cattle raised at Konuklar State Farm in Turkey, using MTDFREML. S. Afr. j. anim. sci. [online]. 2009, vol.39, n.1, pp.10-14. ISSN 2221-4062.

A total of 3696 Test Day Milk Yield (TDMY) records of Brown Swiss cows raised at Konuklar State Farm in the Konya Province of Turkey were used for estimating phenotypic and genetic parameters for TDMY. The phenotypic and genetic parameters were estimated by an MTDFREML programme using a Single Trait Animal Model (STAM). The model included additive direct effects, maternal permanent environment and errors as random effects, parity, year and season of calving as fixed effects, and days in milk (DIM) as a covariate. Genetic parameters and breeding values for TDMY in kg were estimated. The TDMY least square mean was estimated as 15.64 ± 5.82 kg, and the direct heritability (h²_a), maternal heritability (h²m) and the repeatability (r) of TDMY were calculated as being 0.28 ± 0.09, 0.04 ± 0.54 and 0.31 ± 0.01, respectively. The effects of parity and year-season of calving on TDMY were significant.

Keywords : Heritability; repeatability; breeding values.

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