Estimation of Phenotypic and Genetic Parameters and Effect of Some Factors on Birth Weight in Brown Swiss Calves in Turkey Using MTDFREML

The objective of this study was therefore to assess the influence of the age of dam, sex of calf, birth type, season and year of birth of the calf on birth weight and to estimate phenotypic and genetic parameters for birth weight for Brown Swiss cattle in Turkey using Multiple Trait Derivative Free Restricted Maximum Likelihood (MTDFREML). A total of 1437 calf birth weight records of Brown Swiss cows raised at Altınova State Farm in Konya Province were used for estimation of phenotypic and genetic parameters for calf birth weight. Phenotypic and genetic parameters were estimated by MTDFREML programme using a Single Trait Animal Model (STAM). The model included additive direct effect, maternal permanent environment and errors as random effects, birth type, sex of calf, season of birth, year of birth and age of dam as fixed effects. Calf birth weight least square mean was determined as 39.20 ± 2.42 kg, the direct heritability (h2 a), maternal heritability (h2 m) and the repeatability (r) of calf birth weight were calculated as 0.12 ± 0.06, 0.15 ± 0.006 and 0.12 ± 0.06, respectively. The breeding value of dam, sire and calves were calculated. Minimum and maximum breeding value of calves and its accuracy were -1.037 ± 0.66, 0.979 ± 0.68, 0.41 and 0.45, respectively. The effect of birth type, sex of calf, season of birth, year of birth and age of dam on calf birth weight were significant (P