Effect of fiber digestibility and conservation method on feed intake and the ruminal ecosystem of growing steers

Sousa, D. O., Mesquita, B. S., Diniz-Magalhaes, J., Bueno, I. C., Mesquita, L. G. and Silva, L. F. P. (2014) Effect of fiber digestibility and conservation method on feed intake and the ruminal ecosystem of growing steers. Journal of Animal Science, 92 12: 5622-5634. doi:10.2527/jas2014-8016


Author Sousa, D. O.
Mesquita, B. S.
Diniz-Magalhaes, J.
Bueno, I. C.
Mesquita, L. G.
Silva, L. F. P.
Title Effect of fiber digestibility and conservation method on feed intake and the ruminal ecosystem of growing steers
Journal name Journal of Animal Science   Check publisher's open access policy
ISSN 1525-3163
0021-8812
Publication date 2014-12-01
Sub-type Article (original research)
DOI 10.2527/jas2014-8016
Open Access Status Not yet assessed
Volume 92
Issue 12
Start page 5622
End page 5634
Total pages 613
Place of publication Champaign, IL United States
Publisher American Society of Animal Science
Language eng
Formatted abstract
Fiber digestibility is an important factor regulating DMI in ruminants. Additionally, the ensiling process can also affect digestibility and chemical composition of the forage. The objective of this study was to investigate effects of sugarcane NDF digestibility (NDFD) and conservation method on intake, rumen kinetics, and the ruminal ecosystem of steers. Eight ruminally cannulated Nellore steers (275 ± 22 kg BW) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Two sugarcane genotypes divergent for stalk NDFD were used: IAC86-2480 with high NDFD and SP91-1049 with low NDFD. Experimental diets were formulated with 40% sugarcane, either freshly cut or as silage, and 60% concentrate on a DM basis. Each experimental period lasted for 14 d, with the last 4 d used for determination of intake, ruminal evacuation, and ruminal fluid collection. The effect of fiber digestibility on DM and NDF intake was dependent on the forage conservation method (P = 0.01). High NDFD increased (P < 0.01) DMI only when sugarcane was offered as silage, having no effect (P = 0.41) on DMI when offered as freshly cut. Conservation method had no effect on total ruminal mass, with only a tendency (P < 0.10) for greater NDF and indigestible NDF ruminal mass in steers fed the low-NDFD genotype. The NDF turnover and passage rates were greater (P < 0.05) for the genotype with high NDFD but only when offered as silage. Liquid turnover rate in the rumen was greater (P = 0.02) for diets containing silage, with no effect of genotype (P = 0.87). There was no effect of NDFD genotype on ruminal pH (P = 0.77); however, diets containing sugarcane as silage increased (P < 0.01) ruminal pH. Total concentration of short chain fatty acids (P = 0.05) and proportions of propionate (P = 0.01) were greater for diets containing fresh sugarcane. Diets with fresh sugarcane increased the ruminal population of Streptococcus bovis (P < 0.01) and Ruminococcus albus (P = 0.03). The relative population of R. albus was also greater (P = 0.04) for diets containing the sugarcane genotype with high NDFD. Feeding diets containing the sugarcane genotype with high NDFD increased Fibrobacter succinogenes population but only when sugarcane was fed as freshly cut (P = 0.02). Using sugarcane genotypes with high NDFD can increase intake and benefit fiber-degrading bacteria in the rumen.
Keyword Cellulolytic bacteria
Conservation method
Fiber digestibility
Intake
Passage rate
Sugarcane
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Veterinary Science Publications
 
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