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    ASSOCIATIONS OF PIT-1 GENE POLYMORPHISM WITH MILK YIELD AND COMPOSITION TRAITS IN BROWN SWISS CATTLE
    (PAKISTAN AGRICULTURAL SCIENTISTS FORUM, 2013) Aytekin, I.; Boztepe, S.
    The present study investigated the genetic variability of Pit-1 polymorphisms (HinfI_ 451 bp) in a total of 301 Brown Swiss cattle, and also evaluated the possible association between the Pit-1 genotypes and dairy traits such as 305 days milk yield (MY305), test day milk yield (TDMY), fat (%), protein (%), lactose (%), density (kg/m3), solids-non-fat (%), total solids (%), freezing point (oC), and also pH and conductivity (uS/cm) of milk. Allele frequencies were found as A: 0.374 and B: 0.626 in HinfI (451 bp) polymorphism in Pit-1 gene. No significant difference was detected between the observed and the expected genotype frequencies via Hardy-Weingberg equilibrium (P> 0.05). The effect of Pit-1 polymorphisms (HinfI_451 bp) was not observed on milk yield and composition in Brown Swiss populations (P> 0.05). The results demostrated that the Pit-1 polymorphisms (HinfI_451 bp) could not be exploited as a candidate gene for selection of dairy traits in Brown Swiss cattle.
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    Genetic analysis of Test Day Milk Yields of Brown Swiss cattle raised at Konuklar State Farm in Turkey, using MTDFREML
    (SOUTH AFRICAN JOURNAL OF ANIMAL SCIENCES, 2009) Zulkadir, U.; Aytekin, I.
    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 (h(a)(2)), maternal heritability (h(m)(2)) 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.