Effects of slow-release urea on ruminal digesta characteristics and growth performance in beef steers
| Autor: | G Hibbard, Niels Bastian Kristensen, Kyle R. McLeod, David L. Harmon, S. E. Kitts, D. E. Axe, Eric S. Vanzant, C. C. Taylor-Edwards |
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| Rok vydání: | 2009 |
| Předmět: |
Male
Rumen Urease Silage ruminant urea Beef cattle nitrogen Cattle feeding steer Random Allocation chemistry.chemical_compound Ammonia Animal science Genetics Animals Urea health care economics and organizations biology Chemistry Body Weight General Medicine Gastrointestinal Contents Diet Agronomy Dietary Supplements biology.protein Non-protein nitrogen Cattle Animal Science and Zoology metabolism non-protein nitrogen Food Science |
| Zdroj: | Taylor-Edwards, C C, Hibbard, G, Kitts, S E, McLeod, K R, Axe, D E, Vanzant, E S, Kristensen, N B & Harmon, D L 2009, ' Effects of slow-release urea on ruminal digesta characteristics and growth performance in beef steers ', Journal of Animal Science, vol. 87, pp. 200-208 . https://doi.org/10.2527/jas.2008-0912 |
| ISSN: | 1525-3163 0021-8812 |
| Popis: | Two experiments were conducted to evaluate the effects of slow-release urea (SRU) versus feed-grade urea on ruminal metabolite characteristics in steers and DMI, gain, and G:F in growing beef steers. Experiment 1 used 12 ruminally cannulated steers (529 +/- 16 kg of BW) to monitor the behavior of SRU in the ruminal environment. Compared with feed-grade urea, SRU decreased ruminal ammonia concentration (P = 0.02) and tended to increase ruminal urease activity (P = 0.06) without affecting ruminal VFA molar proportions or total concentrations (P > 0.20). After 35 d of feeding, the in situ degradation rate of SRU was not different between animals fed urea or SRU (P = 0.48). Experiment 2 used 180 Angus-cross steers (330 +/- 2.3 kg) fed corn silage-based diets supplemented with urea or SRU for 56 d to evaluate the effects on feed intake, gain, and G:F. The design was a randomized complete block with a 2 x 4 + 1 factorial arrangement of treatments. Treatments included no supplemental urea (control) or urea or SRU at 0.4, 0.8, 1.2, or 1.6% of diet DM. Over the entire 56 d experiment, there were interactions of urea source x concentration for gain (P = 0.04) and G:F (P = 0.01) because SRU reduced ADG and G:F at the 0.4 and 1.6% supplementation concentrations but was equivalent to urea at the 0.8 and 1.2% supplementation concentrations; these effects were due to urea source x concentration interactions for gain (P = 0.06) and G:F (P = 0.05) during d 29 to 56 of the experiment. The SRU reduced DMI during d 29 to 56 (P = 0.01) but not during d 0 to 28, so that over the entire experiment there was no difference in DMI for urea source (P = 0.19). These collective results demonstrate that SRU releases N slowly in the rumen with no apparent adaptation within 35 d. Supplementation of SRU may limit N availability at low (0.4%) concentrations but is equivalent to urea at 0.8 and 1.2% concentrations. |
| Databáze: | OpenAIRE |
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