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).

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.

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

The purpose of the study was to determine the effects of average daily gain and age at first calving on the reproductive and milk production traits of Brown Swiss (BS) a.d Holstein Friesian (HF) cattle. For this purpose, daily gains and ages at first calving were divided into two groups which were below the average called as the "slow" or "early" groups and above the average named as "moderate" or "late" groups respectively. BS heifers in the moderate group reached the first insemination age and first calving age 103.7 and 101.7 days earlier (P>0.01) than these in the slow group respectively. The corresponding values for HF heifers were 37.8 and 29.5 days respectively and were not significant. While the average daily gain had negative effects on reproduction traits following the first calving, the daily gain of BS had no effect on the milk production traits in all parities. HF heifers in the moderate group had higher (P>0.05) actual (585 kg) and 305 days milk yield (324 kg) in the second parity. Early calving in both breeds resulted in a significant (P>0.05) reduction in the actual and 305-days milk yield in the first parity. Early calving caused a significant decrease (P>0.05) in the actual milk yield, 305-days milk yield, actual milk fat and 305-days milk fat yield of BS cows in the first parity. Either early or late calving in BS didn't affect on milk traits in second and third parities. The early calving in HF lowered significantly (P>0.05) the actual and 305-days milk yield in first lactation. However, late calving in HF resulted in lower actual milk yield, 305-days milk yield, actual milk fat yield and 305-days milk fat yield in third parity.