Effect of fiber digestibility and conservation method on feed intake and the ruminal ecosystem of growing steers1

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.

Assessment of Chemical Composition of Grain Crops Depending on Vegetative Stage for Feeding

“…Moreover, indices of crop quality assume significance: relationship between soluble carbohydrates and gas production (Coblentz et al, 2013), fiber and chemical composition (Jancik et al, 2008), influence of maturity on fiber quality (Palmonari et al, 2014). Eventually, chemical composition of plants influences on nutrition of animals: digestibility of nutrients taking into account fiber from fodder (Sousa et al, 2014), influence of dietary fiber on health (Gidenne, 2015), on ruminal digestion (Brooks et al, 2014). The objective of this work is assessment of chemical composition grain crops taking into account vegetative phases under conditions of steppe are of the South Urals.…”

Effect of sugarcane fiber digestibility, conservation method and concentrate level on the ruminal ecosystem of beef cattle

“…For this experiment, samples of rumen contents coming from two previous experiments were used (Mesquita 2013; Sousa et al 2014), which presented the results of performance and ruminal kinetics. The experiments were conducted at the College of Veterinary Medicine and Animal Science, University of São Paulo Beef Cattle Research Laboratory (Pirassununga, SP, Brazil).…”

“…In the first experiment (Sousa et al 2014), eight ruminal-cannulated Nellore steers were distributed in two contemporary 4 × 4 Latin Square design. Experimental diets were formulated with 40% sugarcane, either freshly cut or as silage, and 60% concentrate on a DM basis.…”

“…Stalls and bunks were cleaned daily. A detailed description of the diets can be found at Mesquita (2013) and Sousa et al (2014). …”

Digestibility and performance of feeder lambs fed mixed barley grain – barley silage diets with varieties of barley silage selected on the basis of in vitro neutral detergent fibre degradability.

“…When silage was included in a corn-soybean meal diet at 40% (DM), Sousa et al (2014) found that cannulated Nellore steers fed the high NDFD sugarcane had higher DMI than cattle fed the low NDFD variety. Oba and Swift (2014) fed two barley silage varieties, Tyto and Falcon, that differed by 4.4% in 30 h NDFD.…”