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Effects of the supplemental level of protected lysine on performances of holstein dairy cows |
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In K. Han, Y. J. Choi, J. K. Ha, Y. G. Ko, H. S. Lee, S. S. Lee |
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| Abstract |
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The objective of this study was to investigate the optimum level of the rumen protected lysine(RPLys) for early lactating Holstein dairy cow. This experiment was carried out with 16 Holstein dairy cows for 106 days and consisted of 4 treatments : T1(RPLys 0%), T2(RPLys 0.1%), T3(RPLys 0.2%) and T4(RPLys 0.3%). The results obtained are summarized as follows : 1. The daily intakes of feed were similar among treatments, but the digestibility of crude protein tended to increase 0.5-5.0% with ncreased level of RPLys and also the crude fiber digestibility increased(p<0.05). 2. The daily weight gain for cows in T1 was 253 g, which was lower than any other treatments(p<0.05). The highest was 521 g in T3. Also, the body condition score was changed from 3.22 at initial to 3.45 at final. The lowest increase in body condition score as 0.09 was obtained in control and the highest as 0.60 in T3(p<0.01). 3. The total milk production of groups T2, T3 and T4 were higher than T1, as well as total protein, total fat and total solid yield. Especially in T4 treatment group milk yield was higher than other treatments. The content of fat was higher in T2 and T4 compared to other treatments. Other components of milk were not significantly different(p>0.05). The persistencies of lactation were increased in all RPLys treatments, especially, rate of reduction in milk yield was lowest in T4(p<0.05). 4. The total amino acid content in the plasma, as well as plasma lysine content showed no consistent trend with treatments. |
| Keywords:
Rumen Protected Lysine; Milk Yield; Milk Composition; Plasma Amino Acid |
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