Journal of agriculture & life science (농업생명과학연구)

Institute of Agriculture & Life Science, Gyeongsang National University (경상대학교 농업생명과학연구원)
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Effects of TDN/CP Ratio on Nutrient Intake, Digestibility, Ruminal Fermentation and Blood Characteristics of Replacement Dairy Heifers

TDN/CP 비율에 의한 영양소 공급이 젖소 육성우의 영양소 섭취량, 소화율, 반추위 발효 및 혈액특성에 미치는 영향

  • Kim, Gyeom-Heon (Department of Animal Science and Technology, Konkuk University) ;
  • Kim, Hyun-Jin (Research Institute for Agriculture and Life Sciences, Seoul National University) ;
  • Hwang, Won-Uk (Department of Animal Science and Technology, Konkuk University) ;
  • Kim, Soo-Ki (Department of Animal Science and Technology, Konkuk University)
  • 김겸헌 (건국대학교 동물자원과학과) ;
  • 김현진 (서울대학교 농업생명과학연구원) ;
  • 황원욱 (건국대학교 동물자원과학과) ;
  • 김수기 (건국대학교 동물자원과학과)
  • Received : 2015.12.29
  • Accepted : 2016.08.18
  • Published : 2016.10.31
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Abstract

This study was conducted to investigate a proper management and nutrient supply for raising replacement heifers to improve lactating performance. In order to determine a proper TDN/CP ratio that would be suitable for domestic use, 13-month-old replacement heifers were fed in the ratios of 4.6:1(T1) and 4.3:1(T2), respectively, to examine the changes in nutritional intake, digestibility, characteristics of rumen fluid and blood compositions. While dry matter intake was same at 9.0kg/day, CP intake did not show any significant difference, though T2(1.45kg/day) was slightly higher than T1(1.34kg/day). In fiber intake and digestibility, two results showed no significant difference, though T1 was slightly higher than T2. The pH, NH3-N and VFA densities in rumen fluid examined at the fourth hour after feed intake did not show any significant difference either. Overall level of VFA was not influenced largely by the TDN/CP ratio, but the iso-butyrate and iso-valerate levels and the A/P ratio were significantly high in T1(p<0.05). In blood characteristics, the treatments showed no significant difference. In conclusion, the TDN/CP ratios of 4.3:1 and 4.6:1 did not significantly affect the characteristics of the ruminant stomach, but in comparison with digestibility of 13-month-old heifers, the ratio of 4.6:1 was more appropriate for increased intake of fiber and higher digestibility.

본 연구는 국내 실정에 맞는 적정 TDN/CP 비율을 결정하기 위하여 4.6:1(T1)과 4.3:1(T2)의 비율로 생후 13개월령 육성우에게 급여하여 영양소 섭취량, 소화율, 반추 위액 특성 및 혈액조성에 대하여 조사하였다. 건물 섭취량은 9.0kg/day로 동일하였으며, 조단백질 섭취량은 T1이 1.34kg/day, T2가 1.45kg/day로 T2가 조금 높았으나 유의적인 차이는 없었다. 섬유소 섭취량과 소화율은 T1이 조금 높은 경향을 보였으나 유의적인 차이는 없었다. 사료 섭취 후 4시간째 위액의 pH, ammonia-N, VFA 농도를 비교한 결과 처리구간 유의적인 차이를 나타내지 않았다. 전반적인 VFA 수치는 TDN/CP 비율에 따라 큰 영향이 없었으나 T1 처리구에서 iso-butyrate, iso-valerate 및 A/P ratio가 유의적으로 높은 결과를 보였다(p<0.05). 혈액 특성에는 처리구간 유의적인 차이를 나타내지 않았다. TDN/CP 비율이 4.3:1과 4.6:1 수준은 반추위 특성에 큰 영향을 미치지 않았지만, 소화율과 비교하였을 때 생후 13개월령 육성우 시기에는 섬유소 섭취량과 소화율이 증가되는 4.6:1 수준이 보다 적합할 것으로 판단된다.

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