Effects of supplement feeding order on lactation, diurnal variation of ruminal ammonia and urea in the blood and milk of dairy cows
2005
Ikuta, K. (Hyogo-ken. Research Center for Agriculture, Forestry and Fisheries, Kasai (Japan)) | Sasakura, K. | Nishimori, K. | Hankanga, C. | Okada, K. | Yasuda, J.
The present study examined the effects of feeding Order of grain and protein supplements on ruminal nitrogen (N) loss through the diurnal variation of ruminal ammonia N and urea N in the blood and milk of dairy cows. Three ruminally fistulated cows were used in a 3 x 3 Latin square arrangement of treatments; that is, grain supplement fed at the first feed and then the protein supplement at the second (GS-1st), protein supplement fed first and then the grain supplement (PS- 1st), and the grain and protein supplements mixed and divjded into equal portions fed at each supplement feeding time (GP-mix). No differences in the lactation parameters were observed among the treatments. In GS-1st treatment, the increase in the concentration of ruminal ammonia N was inhibited after feeding, and the concentration was lower (P < 0.05) than with the other treatments 1-2 h after basal feeding. The concentrations of urea N in the blood and milk with the GS-1st treatment were the lowest of all treatments throughout the sampling times, and were lower (P < 0.05) than with the GP-mix treatment except for blood levels 1 h after basal feeding. The results suggest that grain feeding before protein feeding can reduce ruminal N loss.
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