@article {SOTONAVARRO2003117,
	title = {Effects of ruminally degraded nitrogen source and level in a high concentrate diet on site of digestion in yearling Boer {\texttimes} Spanish wether goats},
	journal = {Small Ruminant Research},
	volume = {50},
	number = {1},
	year = {2003},
	pages = {117 - 128},
	abstract = {Eight yearling Boer{\texttimes}Spanish wether goats (36.6{\textpm}2.3kg average initial BW) with ruminal and duodenal cannulae were used in an experiment with two simultaneous 4{\texttimes}4 Latin squares to study effects of dietary level of CP, the ratio of ruminally degraded intake N or protein (DIP) to TDN and source of supplemental DIP on site of digestion with a high concentrate diet. Diets were formulated to be (DM basis) 9.2\% CP, without inclusion of urea (U0) or soybean meal (SBM; S0); 11.3\%, CP achieved with 0.73\% urea (U1) or 4.48\% SBM (S1); 13.3\% CP, via use of 1.46\% urea (U2) or 8.90\% SBM (S2); or 15.2\% CP, derived through use of 2.16\% urea (U3) or 13.2\% SBM (S3). The ratio of DIP:TDN was 0.073, 0.104, 0.136, 0.167, 0.073, 0.093, 0.113 and 0.132 for U0, U1, U2, U3, S0, S1, S2 and S3, respectively. Diets contained 30\% cottonseed hulls and were corn-based and fed at 2\% BW (DM basis). Apparent ruminal N digestibility increased quadratically as level of supplemental CP rose (-71.6, -39.9, -20.5, 8.5, -60.3, -12.5, -8.4 and -3.5\% for U0, U1, U2, U3, S0, S1, S2 and S3, respectively; S.E.=6.6). Microbial OM and N flows to duodenum decreased linearly as CP level increased. Ruminal and total tract NDF digestibilities (e.g. total tract: 51.3, 57.6, 57.7, 57.4, 49.7, 52.3, 53.2 and 53.2\% for U0, U1, U2, U3, S0, S1, S2 and S3, respectively) increased linearly and tended to change quadratically as CP level increased. In conclusion, a dietary CP concentration of 11{\textendash}13\% and DIP:TDN ratio of 0.10{\textendash}0.11 were adequate for maximal total tract OM digestibility in meat goats consuming a corn-based, high concentrate diet, regardless of supplementation with a source of non-protein versus natural protein, although magnitudes of difference in digestibility with lower levels were not marked. A dietary CP concentration of 9{\textendash}10\% and ratio of DIP to TDN of 0.073 were sufficient for highest microbial protein production. With ample tissue N reserves, the ability of meat goats to recycle N may preclude realization of substantial benefits from supplementing high concentrate diets around 9\% CP with additional DIP, and high concentrate diets appear to satisfy microbial needs for non-ammonia nitrogenous compounds.},
	keywords = {Goats, Ruminally degraded N, Soybean meal, Urea},
	issn = {0921-4488},
	doi = {https://doi.org/10.1016/S0921-4488(03)00120-2},
	url = {http://www.sciencedirect.com/science/article/pii/S0921448803001202},
	author = {S.A. Soto-Navarro and A.L Goetsch and T Sahlu and R Puchala and L.J. Dawson}
}
