The aim of this study was to determine the reproductive characteristics, milk yield and milk quality of Primiparous Red-Holstein (RH) and Holstein-Friesian (HF) cows. For this aim, records and monthly taken milk samples of 83 RH and 14 HF raised on a farm in Aydın, Turkey were used. The averages of the first calving age (FCA), gestation length (GL), days open (DO), calving interval (CI), daily milk yield (DMY), 305-day milk yield (305-dMY), solid non-fat (SNF) and Log10 somatic cell count (Log10SCC) of milk were found to be 27.6±0.24 mo, 278.4±1.09 d, 144.0±7.12 d, 421.4±7.66 d, 22.7±0.21 kg, 6981±137.0 kg, 9.8±0.04% and 4.59±0.024 (38905 cells/ml), respectively. Except for DMY, the differences between the breeds were statistically insignificant for FCA, GL, DO, CI, 305-dMY, SNF and Log10SCC. DMY averages for RH and HF were 21.8±0.21 kg and 24.3±0.49 kg, respectively. The effect of season on FCA and the effect of lactation month on SNF and Log10SCC were also found to be statistically significant. Apart from DMY, not any significant difference was observed between RH and HF breeds in terms of the characteristics emphasized.

Effects of two dietary levels of starch and crude protein on performance of dairy cow fed low roughage level (70:30 concentrate to roughage) were investigated. Twenty eight Holstein cows were randomly assigned to one of four dietary treatments in a 2 x 2 factorial arrangement. Factors were two dietary level of starch (14% and 22%) and crude protein (15% and 18%). Wheat straw was used as sole roughage source. The study was continued 6 weeks. Dry matter intake was not affected (P>0.05) by the dietary treatments in the study. Milk and protein yield (kg/d) were higher (P

Selection of dairy cattle for higher milk yield, without considering important non-production traits, has decreased reproductive efficiency. Thus, low reproductive performance is a major problem in high yielding dairy cattle. Previous studies showed that dietary manipulation to improve fertility holds much promise and dietary fats have positive effects on reproductive functions in high yielding dairy cattle. Positive effects of fats on reproductive performance due to the fatty acids, which are the precursors of progesterone and prostaglandins. Progesterone and prostaglandins hormones are most important factors that play a role on the control of reproductive functions. The amount of linoleic, linolenic and arachidonic fattty acids in ration can be increase or decrease progesterone and prostaglandins synthesis especially PGF2α from ovary and uterus, respectively. Also fatty acids can be influence follicular development, ovulation, embryonic implantation and maternal recognition of pregnancy. This review focuses on the relationships between dietary fatty acids and reproductive functions such as hormone profiles, ovarian function and follicular development, oocyte quality, embryo development, embryonic implantation and maternal recognition of pregnancy in dairy cattle.