This study was designed to investigate the carryover effects of high-forage to concentrate (F: C) diet in bred heifers on feed intake, feed efficiency (FE) and milk production of primiparous lactating Holstein cows. The experiment was conducted for 589 days (d) from onset of pregnancy through to the end of first lactation. Twenty-four bred heifers (Body weight: BW= 345.8 ± 45.4 kg and 15 ± 1.2 mon of age) randomly assigned to two groups of 3 pens containing 4 heifers each and fed high forage (HF) diet with F: C ratio of 91.7: 8.3% and low forage (LF) diet with F: C ratio of 77.8: 22.2% throughout the pregnancy period. After calving, lactating cows were fed total mixed ration (TMR) based diet. No differences (p > 0.05) were observed in dry matter intake (DMI) of bred heifers and primiparous lactating cows in both HF and LF groups. The FE of mid-to-late lactation period was higher (p< 0.05) in HF than LF group. However, the HF group showed higher (p < 0.05) milk yield, 4 % fat corrected milk (FCM) and energy corrected milk (ECM) than LF group during the 305 d lactation. The LF group showed higher (p < 0.05) milk fat, crude protein (CP), milk urea nitrogen (MUN), solid not fat (SNF) and somatic cell count (SCC) than HF group. It is concluded that restriction of F: C ratio to 91.7: 8.3% to bred heifers has the potential carryover effects to maintain higher milk yield and FE with no adverse effect on feed intake and milk composition of primiparous lactating Holstein cows.

The increase in the total number of cows on farms, which breed Korean Native Cattle (KNC), is associated with many problems. In particular, the services per conception and calving interval have increased. In this study, we examined the effect of dietary supplementation with vitamin and mineral complex on the estrus rate, pregnancy rate, gestation length, and birth weight of KNC calves. Multiparous or primiparous KNC were divided into 3 groups with 40 heads per group. Experimental group 1 was administered a consisting of 35,000 IU vitamin A, 100 IU vitamin E, 200 mg -carotene, 200 mg Zn methionine, and 1.5 mg Se. Experimental group 2 was administered a vitamin complex (100 g/day) consisting of 100 IU vitamin E and 200 mg -carotene. In the case of multiparous KNC, the estrus detection rate in the control group was 90.0% and those in the experimental groups were 75.0% to 95.0%. However, the first-service pregnancy rate after parturition in the control group was 41.2%, which was significantly lower than that in the experimental groups (71.0% to 76.7%; p<0.05). The average duration of pregnancy in the group supplemented with the vitamin complex was days, which was similar to that in the case of the control group. The birth weight of calves from cows fed with vitamin complex was 25.3 to 27.0 kg, which was similar to that in the case of the control group (25.2 to 26.0 kg). In the case of primiparous KNC, no differences in the estrus rate, pregnancy rate, gestation length, or the birth weight of calves were noted between the groups. Thus, dietary supplementation vitamin and mineral complex have no effect on the reproductive efficiency in primiparous cows, but the pregnancy rate was observed to have increased in multiparous KNC with these supplements.