J.E. Rossi

Bio: J.E. Rossi is an academic researcher from University of Arkansas. The author has contributed to research in topics: Hay & Neutral Detergent Fiber. The author has an hindex of 6, co-authored 10 publications receiving 89 citations.

Net flux of nutrients across splanchnic tissues in wethers consuming grasses of different sources and physical forms ad libitum

Abstract: Crossbred sheep (n 16, 8.5 months of age and 33 (SE 0.9) kg) were used in a 21 d experiment (2 x 2 factorial) to determine effects on net flux of nutrients across the portal-drained viscera (PDV) and liver of ad libitum consumption of bermudagrass (Cynodon dactylon; B) v. ryegrass (Lolium multiflorum)-wheat (Triticum aestivum; RW) hay, coarsely chopped (CC) or finely ground and pelleted (GP). Crude protein concentrations were 86, 81, 113 and 119 g/kg and neutral-detergent fibre concentrations were 710, 688, 654 and 672 g/kg (dry matter basis) for B-CC, B-GP, RW-CC and RW-GP respectively. Digestible energy intake (6.0, 9.6, 10.2 and 13.8 MJ/d) differed (P < 0.01) with grass source and form, and digestible N intake values were 4.4, 7.0, 8.4 and 14.1 (SEM 0.82) g/d for B-CC, B-GP, RW-CC and RW-GP diets respectively. Consumption of O2 by the PDV (118, 165, 144 and 155 mmol/h) and splanchnic bed (196, 273, 247 and 266 mmol/h for B-CC, B-GP, RW-CC and RW-GP respectively) was greater (P = 0.07) for GP than for CC. The ratio splanchnic heat energy production: digestible energy intake was greater (P = 0.06) for B than for RW (0.374, 0.300, 0.278 and 0.219 for B-CC, B-GP, RW-CC and RW-GP respectively). alpha-Amino-N release by the PDV (P < 0.01; 11.6, 12.8, 23.0 and 18.7 mmol/h) and uptake by the liver (P = 0.07; 15.2, 6.1, 17.0 and 19.3 mmol/h for B-CC, B-GP, RW-CC and RW-GP respectively) were greater for RW than for B. Release of NH3-N by the PDV was greater (P = 0.02) for CC than for GP (12.5, 6.2, 15.7 and 8.9 mmol/h), and hepatic urea-N release differed between grass sources (P = 0.03) and physical forms (P = 0.07; 22.6, 12.7, 31.4 and 24.8 mmol/h for B-CC, B-GP, RW-CC and RW-GP respectively). In conclusion, decrease in forage particle size elicited by grinding and pelleting did not affect the difference between grass sources in splanchnic tissue heat energy production relative to digestible energy intake.

Oxygen consumption by splanchnic tissues in wethers consuming ad libitum different proportions of bermudagrass and ryegrass-wheat.

Abstract: Crossbred wethers (n = 18, 7.5 month of age and 31 +/- 0.8 kg) were used in a 23-day experiment to determine effects of ad libitum consumption of diets differing in proportions of coarsely chopped bermudagrass and ryegrass-wheat hay (0, 33, 67 and 100%) on oxygen consumption by splanchnic tissues. Bermudagrass and ryegrass-wheat were 9 and 13% CP and 78 and 71% NDF, respectively. Intake of dry matter (1.03, 0.92, 0.92 and 0.76 kg/d) and digestible energy (13.5, 10.7, 10.6 and 8.2 MJ/d for 0, 33, 67 and 100% bermudagrass, respectively) changed linearly and cubically (P < 0.05) as bermudagrass level increased. Consumption of oxygen by the portal-drained viscera tended to decrease linearly (P = 0.14) with increasing bermudagrass (182, 154, 156 and 137 mM/h), and hepatic oxygen consumption decreased linearly (P < 0.05) and changed cubically (P = 0.07; 150, 113, 116 and 103 mM/h for 0, 33, 67 and 100% bermudagrass, respectively). Splanchnic tissue energy consumption expressed as a percentage of digestible energy intake increased linearly (P = 0.08) with increasing bermudagrass (24.0, 27.6, 28.6 and 33.2% for 0, 33, 67 and 100% bermudagrass, respectively). In conclusion, the level rather than presence alone of different grass sources consumed ad libitum affected energy use by the splanchnic bed, and as a percentage of digestible energy intake splanchnic bed energy consumption increased with increasing dietary bermudagrass level and decreasing digestible energy intake.

Nutritional requirements of sheep, goats and cattle in warm climates: a meta-analysis

Abstract: The objective of the study was to update energy and protein requirements of growing sheep, goats and cattle in warm areas through a meta-analysis study of 590 publications. Requirements were expressed on metabolic live weight (MLW=LW0.75) and LW1 basis. The maintenance requirements for energy were 542.64 and 631.26 kJ ME/kg LW0.75 for small ruminants and cattle, respectively, and the difference was significant (P<0.01). The corresponding requirement for 1 g gain was 24.3 kJ ME without any significant effect of species. Relative to LW0.75, there was no difference among genotypes intra-species in terms of ME requirement for maintenance and gain. However, small ruminants of warm and tropical climate appeared to have higher ME requirements for maintenance relative to live weight (LW) compared with temperate climate ones and cattle. Maintenance requirements for protein were estimated via two approaches. For these two methods, the data in which retained nitrogen (RN) was used cover the same range of variability of observations. The regression of digestible CP intake (DCPI, g/kg LW0.75) against RN (g/kg LW0.75) indicated that DCP requirements are significantly higher in sheep (3.36 g/kg LW0.75) than in goats (2.38 g/kg LW0.75), with cattle intermediate (2.81 g/kg LW0.75), without any significant difference in the quantity of DCPI/g retained CP (RCP) (40.43). Regressing metabolisable protein (MP) or minimal digestible protein in the intestine (PDImin) against RCP showed that there was no difference between species and genotypes, neither for the intercept (maintenance=3.51 g/kg LW0.75 for sheep and goat v. 4.35 for cattle) nor for the slope (growth=0.60 g MP/g RCP). The regression of DCP against ADG showed that DCP requirements did not differ among species or genotypes. These new feeding standards are derived from a wider range of nutritional conditions compared with existing feeding standards as they are based on a larger database. The standards seem to be more appropriate for ruminants in warm and tropical climates around the world.

Splanchnic tissue energy use in ruminants that consume forage-based diets ad libitum.

Abstract: The effects that characteristics of forage-based diets on gut and liver energy use in sheep with ad libitum consumption were discussed, and practical consequences of diet and animal effects on splanchnic energy use were projected. Explained variation in portal-drained viscera (PDV) and hepatic energy use by sheep in recent experiments increased when independent variables were included in regressions on DE intake (DEI) (PDV: R 2 = 33 vs 22%; liver: R 2 = 48 vs 25%). The regression equations used were the following: PDV energy use, Mcal/d = -.0194 + (.1207-DEI, Mcal/d) + (1.1173-fecal NDF excretion, kg/d) - (.2860-DEI-fecal NDF excretion) and hepatic energy use, Mcal/d =.0014 + (.0266-DEI, Mcal/d) + (.3325-PDV energy use, Mcal/d) + (.0745-urea N hepatic net flux, mol/d) + (.0016-BW, kg). Thus, gut digesta, as implied by fecal NDF excretion, seemed to influence PDV energy use in addition to the effect of DEI, and energy consumption by the liver seemed affected by PDV energy use and hepatic ureagenesis. A regression equation (R 2 = 49%) for splanchnic bed energy use, expressed as a percentage of DEI, was 43.61 - (9.531-DEI, Mcal/d) + (15.914-fecal NDF excretion, kg/d) + (6.057-urea N hepatic net flux, mol/ d). If physiological control of feed intake with effect of efficiency of energy metabolism is assumed, and if whole-body efficiency of energy metabolism with ad libitum intake is constant, then efficiency of energy metabolism in extrasplanchnic tissues decreases as level of ad libitum intake and the ratio of splanchnic bed energy use to DEI decrease. Therefore, animal characteristics (e.g., maturity, body condition, and biological type) and grazing conditions (e.g., forage mass) may affect feed intake by influencing heat production by peripheral tissues. In conclusion, an increased understanding of dietary influences on efficiency of splanchnic tissue metabolism may lead to enhanced efficiency of forage utilization and ruminant production systems.

Repeated inoculation of cattle rumen with bison rumen contents alters the rumen microbiome and improves nitrogen digestibility in cattle.

Abstract: Future growth in demand for meat and milk, and the socioeconomic and environmental challenges that farmers face, represent a "grand challenge for humanity". Improving the digestibility of crop residues such as straw could enhance the sustainability of ruminant production systems. Here, we investigated if transfer of rumen contents from bison to cattle could alter the rumen microbiome and enhance total tract digestibility of a barley straw-based diet. Beef heifers were adapted to the diet for 28 days prior to the experiment. After 46 days, ~70 percent of rumen contents were removed from each heifer and replaced with mixed rumen contents collected immediately after slaughter from 32 bison. This procedure was repeated 14 days later. Intake, chewing activity, total tract digestibility, ruminal passage rate, ruminal fermentation, and the bacterial and protozoal communities were examined before the first and after the second transfer. Overall, inoculation with bison rumen contents successfully altered the cattle rumen microbiome and metabolism, and increased protein digestibility and nitrogen retention, but did not alter fiber digestibility.