EFFECT OF CONCENTRATE TYPE ON DIETARY NITROGEN PARTITION IN LACTATING FRIESIAN HOLSTEIN CROSSBREED COWS

Abstract

This research was conducted to determine the effect of different concentrate type on dietary nitrogen partition in lactating Friesian Holstein crossbreed cows (FHC). Four lactating Friesian Holstein crossbreed cows were fed four different concentrate types and degradation rates, namely rapidly degraded starchy concentrate (PC); slowly degaded starchy concentrate (PL); rapidly degraded fibrous concentrate (SC); slowly degraded fibrous concentrate (SL). This research was done in four periods using 4 x 4 Latin Square Design. All animals were fed King grass (Permiretum hybrid) ad libilum as a basal diet and concentrate, with roughage to
concentrate ratio of 60 : 40. Data was analyzed using variance analysis, followed by Duncan’s Multiple Range Test to determine effect of treatment and orthogonal contrast analysis to determine effect of concentrate types and degradation rates. Results on parameters of ruminal fermentation showed that ruminal pH for SL was higher (P<.05) than that of PC, PL and SC at all sampling time. The effect of concentrate types on ruminal pH was significant difference at 2, 3, 4 h post feeding, meanwhile effect of concentrate degradation rate was significant difference
at 1, 2, 3, 4, 6, 8 h post feeding. Ruminal NH; for PL was higher (P<.01) than that of PC, SL and SC at 1 h post feeding, meanwhile SL was higher (P<.05) than of PL, SC and PC at 3, 4 6 h post feeding. Organic matter degradation in the rumen of PC was higher (P<.01) than that of PL, SC and SL at all incubation time. Milk N secretion and N retention were not significantly affected ‘by the treatments. N secretion for PC, PL, SC and SL were 27.8, 18.5, 21.1, and 129.6 g/head/day respectively, meanwhile the N retention were 74.8, 74.3, 96.6 and 62.9 g/head/day respectively. The efficiency of dietary N utilization was not significantly difference among treatments, but PC concentrate tended to be the most efficient.