Yazarlar

• Akbulut, O.(2)
• Aksakal, V.(2)
• Bayram, B.(2)
• Aksakal, Vecihi(1)
• Bayram, Bahri(1)
• Yanar, M.(1)
• Yanar, Mete(1)

• MakaleYalnız künye2012/r/gumushane/16824
  EFFECT OF THE BODY CONDITION SCORE ON SOME REPRODUCTION AND MILK YIELD TRAITS OF SWEDISH RED AND WHITE COWS

  Bayram, B.; Aksakal, V.; Akbulut, O.

  This study examined the effect of body condition score (BCS) at calving and during the first month of lactation on some reproduction and milk yield traits of Swedish Red and White (SRW) cows organically raised in Turkey. For this purpose, SRW cows divided two groups, named as thin (BCS <3.00) and moderate (BCS >= 3.00). The actual milk yield (815 kg) and 305 day daily milk yield (736 kg) of cows with low condition score at calving were significantly (P<0.01) higher than those with moderate condition score. The BCS at calving did not have an effect on the lactation length, peak daily milk yield and days to attain peak milk yield. The condition score obtained in the first month of lactation only affected the peak daily milk yield (P<0.05), while its impact on the other characteristics was non-significant. The service period of the cows with low condition score at calving was significantly longer (19.9 day) and their number of services per conception was significantly lower (0.37 units) (P<0.05) than moderate group. The condition loss was calculated as 0.0137 units in the thin group and 0.2290 units in the moderate group and this differences were significant (P<0.01) during the first 30 day period of lactation. The phenotypic correlation between BCS at calving and milk yield traits were negative and significant (P<0.01). According to this relationship, actual milk yield (r=-0.208), 305 day milk yield (r=-0.248) and peak daily milk yield (r=-0.251) decreased significantly (P<0.01) with the increase in the BCS at calving. The service periods of cows with low condition scores at calving were significantly longer (P<0.01).

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• MakaleYalnız künye2012/r/gumushane/12034
  Estimation of variance components and heritability of birth weight through different methods in Swedish Red and White cattle

  Aksakal, V.; Bayram, B.; Yanar, M.; Akbulut, O.

  Data on 368 birth records of Swedish Red and White cattle herd raised organically at Dogan Organic Dairy Cattle Farm for a period of 2006 and 2009 (4 years) were used to estimate the effects of different environmental factors on birth weight. Additionally, a comparison of four methods for variance component estimation to compute heritability of birth weight was performed using ML (Maximum likelihood), MINQUE (Minimum variance quadratic unbiased estimation), REML (Restricted maximum likelihood) and Henderson's Method III. Average abortion rate, stillbirth rate, twin and single birth rates of Swedish Red and White cattle were as 4.5%, 4.3%, 3.2% and 87.7% respectively. The least squares mean for birth weight was 37.4±0.70 kg. While effects of calving year (P<0.01), calving season (P<0.05) and sex of calve (P<0.01) were significant, and the effect of age of dam was not significant (P>0.05). Sire and error variance components and standard error of the heritability obtained by using ML method were lower than those obtained by the other three methods. Heritability estimates for birth weight obtained by ML, REML, MINQUE and Henderson Method III were 0.57±0.22, 0.62±0.24, 0.65±0.25 and 0.59±0.24, respectively. It is concluded that the ML procedure was superior for estimating variance components and heritability of birth weight of Swedish Red and White cattle and non-genetic factors influencing the birth weight should also be considered in selection and an adjustment for the significant environmental factors should be made.

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• MakaleYalnız künye2010/r/gumushane/15617
  Non-genetic factors affecting milk and reproductive traits of Swedish Red and White cattle raised organically in Turkey

  Aksakal, Vecihi; Yanar, Mete; Bayram, Bahri

  The data on breeding and performance records of Swedish Red and White (SRW) cows kept in a private organic dairy farm in Kelkit, Turkey, during the period from 2006 through 2009 were used to study the effect of some non-genetic factors such as calving year, calving season, parity, age of dam and sex of calf on the various milk and reproductive traits. The actual lactation milk yield, daily milk yield, peak daily milk, days to attain milk yield and lactation length averaged as 5887.2±94.9 kg, 19.9±0.3 kg, 31.5±0.3 kg, 79.4±2.7 days and 302.5±3.2 days, respectively. The actual lactation milk yield, days to attain peak milk yield and lactation length were significantly affected by calving year and calving season. The effect of the parity on the daily milk yield, peak daily milk yield and days to attain peak milk yield were significant (P<0.01). The least squares means for calving interval and gestation length were 380.2±4.3 days and 275.4±0.6 days, respectively. Age of dam and calving season significantly (P<0.01) affected the days open. Mean age at first calving of SRW cows raised organically was 26.4±0.2 months and was significantly affected by the calving years. Significant (P<0.01) and positive phenotypic correlations of the actual lactation milk yield with daily milk yield (r = 0.71), peak milk yield (r = 0.53), lactation length (r = 0.53), days open (r = 0.43), calving interval (r = 0.36) and days attain to peak milk yield (r = 0.14) (P<0.05) were determined. In conclusion, the significant effects of environmental variables must be taken into consideration when developing and comparing models to be used in adjusting data to provide the best estimates of genetic values and parameters in evaluation of SRW cattle reared organically in Turkey.

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