We compared the reproductive performance, non-productive performance, and milk composition performance of two groups of lactating cows that were either rice straw or tall fescue. We also compared and analyzed these parameters after the first parturition during the breeding period. The calving interval, artificial insemination, and duration from calving to conception were longer in the rice straw group than in the tall fescue group. The 305-day and peak milk yields were significantly higher in the tall fescue group than in the rice straw group (p<0.01). Milk fat content was significantly higher in the tall fescue group than in the rice straw group (p<0.001), but milk protein content was the same between the feeding groups. The difference in raw milk sales income between rice straw and tall fescue groups tended to increase as the number of lactations increased, but there was no effect of reduced feed costs. Analysis of the milk production and raw milk sales income of the surveyed farms revealed that the average milk production per head was significantly (p<0.05) higher in the tall fescue group than in the rice straw group, and raw milk sales income showed a similar tendency. Overall, these results provide important details to be considered when selecting feed as a way to reduce milk production and heifer raising costs. However, there remains a need for future follow-up studies exploring the relationship between feed choice and the management of heifers.

본 연구는 젖소에 있어서 삭제가 번식효율에 미치는 영향을 구명하기 위하여 2003년부터 2004년까지 2년간에 걸쳐 축산연구소 개방형 깔짚 우사에서 사육중인 홀스타인 착유우 17두를 대상으로 처리구 9두 및 대조구 8두를 공시하였고 삭제는 분만 후 20일을 전후하여 1회에 한해 실시하여 다음과 같은 결과를 얻었다. 1. 삭제에 따른 분만 후 첫 수정일수는 대조구가 180.931.6, 삭제구가 111.917.1일로 삭제구가 대조구에 비하여 분만 후 첫 수

This study was carried out to investigate the effect of DDGS hydrolysate (H-DDGS) and rumen-protected lysine-choline complex (RPLC) on milk production and blood metabolites in dairy cows. Feeding trials was performed to latin-square design using the 4 mid-lactational cows for 8 weeks, and treated with T1 (H-DDGS 1.1 kg), T2 (H-DDGS 0.73 kg + RPLC 0.15 kg), T3 (H-DDGS 0.37 kg + RPLC 0.30 kg) and T4 (H-DDGS 0.37 kg + RPLC 0.15 kg) according to the content of protein source. Dry matter intake (DMI) of TMR and average weight showed no significant difference between treatments. The milk production of T1, T2 and T4 were significantly higher than T3 treatment (p < 0.05), and milk/DMI efficiency tend to increase in the T1. Milk components showed no significant difference between treatments, however, the milk protein of T2 increased to 0.15% than T1. Also blood metabolites showed no significant difference between treatments. But T-CHO level numerically represented a lower trend in the treatments of adding to RPLC compared with T1. This result suggests that the high level (1.1 kg) of H-DDGS is expected to improve the feed utilization without the negative impact on weight gain, feed intake and milk production as the lactation stage of dairy cows proceeds, and 0.15 kg of RPLC under the same feeding conditions of H-DDGS may be useful on fat metabolism.