This study was carried out between 2008 and 2009 in four dairy farms to investigate the effect of feeding of whole crop barley silage on the reproductive performance of Holstein heifers. Two diets, mixed hay or whole crop barley silage separately from concentrate were fed 6-month old Holstein heifers (=37). In control group (=CON), heifers (n=16) were fed 6 kg (/head) mixed hay and 4 kg (/head) commercial diet. In whole crop barley silage group (=WBS), heifers (n=21) were fed 10 kg (/head) whole crop barley silage, 4 kg (/head) mixed hay and 2 kg (/head) commercial diet. To manage body weight gain, the body condition score of heifers were measured every month. The results obtained were as follows: 1. Body weight in CON and WBS heifers at 13-, 14-, 15- and 17-month old were 340±17.9 and 342±13.6 kg, 356±15.7 and 366±14.7 kg, 382±13.1 and 387±14.4 kg, and 429±15.0 and 417±10.3 kg, respectively. 2. Body condition score in CON and WBS heifers at 9-, 12-, 15- and 17-month old were 2.88±0.04 and 2.80±0.04, 2.88±0.04 and 2.80±0.04, 2.89±0.08 and 3.00±0.07, and 2.89±0.08 and 3.00±0.07, respectively. 3. Average age of sexual maturity in CON and WBS heifers were 437.3±9.9days and 939.6±12.5days, WBS group heifers were significantly shorter (p<0.05) than CON group heifers. 4. First-service conception rates in CON or WBS group were 81.3% (13/16) and 66.7% (14/21), respectively, and cumulative conception rate to 2nd artificial insemination were 87.5% for CON and 85.7% for WBS group. Conception rate was not different between treatments

s study was carried out between November 2008 and October 2009 in the experimental farm of Chunnam National University to investigate the effect of feeding of Sudangrass silage on the reproductive performance of Hanwoo cows. Two diets, rice straw or Sudangrass silage separately from concentrate were fed 19 Hanwoo cows. In control group (=CON), cows (n=9) were fed 5 kg (/head) rice straw and 3 kg (/head) commercial diet. In Sudangrass silage group (=SGS), cows (n=10) were fed 12.5 kg (/head) Sudangrass silage and 1 kg (/head) commercial diet. 1. Days to post-partum insemination were 78.8±25.3 days for CON and 84.7±24.6 days for SGS group and days to post-partum conception in CON or SGS were 90.1±24.1 and 87.7±26.8 days, respectively. 2. Post-partum conception rates for first service in CON or SGS was 66.7% and 90.0%, respectively, and caving interval was 375.1±46.7 days for CON and 370.2±34.4 days for SGS group. 3. Body Condition Scores of Hanwoo cows at artificial insemination was 5.36 for CON group and 4.93 for SGS group.

This study was carried out between November 2007 and October 2008 in the experimental farm of Chunnam National University to investigate the effect of feeding of whole crop barley silage on the reproductive performance of Hanwoo heifers and cows. Two diets, rice straw or whole crop barley silage separately from concentrate were fed 11 Hanwoo heifers and 26 Hanwoo cows. In control group (=CON), heifers (n=6) and cows (n=13) were fed 7 kg (/head) rice straw and 4 kg (/head) commercial diet. In whole crop barley silage group (=WBG), heifers (n=5) and cows (n=13) were fed 8 kg (/head) whole crop barley silage and 1 kg (/head) commercial diet. 1. Conception rates for first service in CON or WBG heifers were 66.7% (4/6) and 60.0% (3/5), respectively, and the services per conception cows were 1.5±0.2 for CON and 1.4±0.2 for WBG group. 2. Days to post-partum insemination were 106.6±26.3 days for CON and 85.6±12.6 days for WBG group, and days to post-partum conception in CON or WBG were 128.4±27.1 and 96.8±16.8 days, respectively. 3. Post-partum conception rates for first service in CON or WBG were 76.9% (10/13) and 84.6% (11/13), respectively, and caving interval was 418.1±50.7 days for CON and 392.8±20.7 days for WBG group.