Holstein 젖소에서 조사료 급여 수준이 유방크기, 호르몬 및 산유특성에 미치는 영향:육성기부터 비유기까지

초록

In the present study, we investigated the effects of high forage diets on the volume of udder, hormone level in blood, and lactation characteristics in the Holstein dairy cow. We divided into two groups; high forage diet [HF, concentrate: forage=4:6 n=41] and low forage diet[LF, 6:4 n=21]. Five cows were selected from each group based on their age for measuring the udder volume and the serum levels of estradiol and progesterone. Lactation characteristics were compared between HF and LF. The udder volume was 2.5 fold larger in HF at early gestation(p<0.01), but no difference was noted afterward. For the hormone levels, no significant difference was found between the groups. In HF, milk yield was significantly increased and maintained high longer, while somatic cell count was approximately 50% lower. Meanwhile, the milk fat content was significantly lower in HF during early lactating phase(p<0.001), but there was no difference thereafter. For milk protein and solid content, and MUN, no differences were found between the groups during lactation. Our results indicated that feeding high forage diets to dairy cows can increase milk yield and quality without notable changes in the udder volume and hormone level.

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