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Byproducts in livestock diets have the potential to reduce the environmental impact of food production and the cost of animal feeding. The objective was to evaluate the extent and rate of nutrient degradability of potato and other byproducts by rumen microorganisms in vitro. Byproducts included barley malt sprouts, fries, dry peel, and hopper, which were supplied by Performix Nutrition Solutions (Nampa, ID). Two in vitro incubators (DAISYII, ANKOM Technology) each with four incubation jars were used to evaluate ruminal degradability of dry matter (DM) and neutral detergent fiber (NDF). Each jar contained 1,600 mL buffer solution (ANKOM Technology), 400 mL rumen contents (collected from two ruminally cannulated cows), 14 filter bags (F57, ANKOM Technology) with 0.5 g of ground byproduct, 14 filter bags with 0.5 g of ground corn (standard), and 14 blank bags. Each jar was purged with CO2 and filter bags were incubated at 39°C for 0, 3, 6, 9, 12, 24, and 48 h, then removed, rinsed, dried at 55˚C for 48 h, weighed, and analyzed for DM and NDF. Each byproduct was incubated in 3 jars on two different d (6 replicates). Degradation of DM was separated into fractions A (disappearance at 0 h), C (DM remaining after 48 h) and B (100%-A-C). Rate of degradation for fraction B was the slope of the natural logarithms of the DM disappearance. All byproducts were compared with standard corn grain as the control. Fraction A for DM was not different (P > 0.40) for barley malt sprouts (35.4%) and hopper (33.7%), and less (P < 0.05) for dry peel (27.8%) and fries (13.2%) when compared with corn grain (33.4%). Fraction B for DM was greater (P < 0.05) for fries (74.0%), not different (P = 0.44) for hopper (56.1%), and less (P < 0.05) for dry peel (43.6%) and sprouts (37.0%) when compared with corn grain (53.9%). Rate of DM degradation for fraction B was greater (P < 0.05) for fries (9.9%/h) and hopper (7.0%/h), and not different (P > 0.16) for dry peel (4.6%/h) and sprouts (3.0%/h) when compared with corn grain (3.8%/h). Fraction C for DM was greater (P < 0.05) for dry peel (28.6%) and sprouts (27.6%), and not different (P = 0.20) for fries (12.9%) and hopper (10.3%) when compared with corn grain (12.7%). The indigestible frac- tion of NDF after 48 h of incubation was greatest for dry peel (58.5%), intermediate for sprouts (40.1%) and hopper (36.7%), and least for fries (25.4%; P < 0.05). These results demonstrate that the extent and rate of ruminal DM degradability of various potato and other byproducts differ and may be more or less degradable in the rumen compared with corn grain. [ABSTRACT FROM AUTHOR]

The effects of dried distillers grains plus solubles (DDGS) supplementation on ruminal degradation kinetics of steers fed annual ['Tiffany'Eragrostis tef (Zucc.) Trotter; TEFF] or perennial ['WW-B Dahl' Old World bluestem, Bothriochloa bladhii (Retz).T. Blake; OWB] grass hay were evaluated. Ruminally cannulated crossbred-Angus steers (n = 6; BW = 304 ± 11 kg) were assigned to a 4 × 6 unbalanced Latin square design with 4 treatments. Treatments were arranged as a 2 × 2 factorial, with factors being hay type (OWB or TEFF) and DDGS supplementation [0 or 0.5% BW (DM basis)]. Steers had ad libitum access to hay and received 110 g of a mineral/vitamin packet daily. Periods consisted of a 14-d adaptation followed by 7 d of collection. Hay types were reverse-incubated at 0, 3, 6, 12, 24, 36, 48, 72, and 96 h post-feeding. Residues from the in situ incubations were fitted to a first-order kinetics model using the non-linear procedure of SAS. The GLIMMIX procedures of SAS were used for the statistical analysis. A hay type × DDGS interaction was observed (P = 0.05) for the estimation of substrate effective degradable fraction of OM, NDF, ADF, and hemicellulose; however, after adjusting with Tukey's, there were no treatment mean differences (P = 0.08). The rate of digestion, soluble fraction, and the potentially degradable fraction of OM, NDF, ADF, and hemicellulose increased (P = 0.05), while the undegradable fraction decreased (P = 0.01) when steers were fed TEFF, regardless of DDGS supplementation. Ruminal degradation lag-time increased (P = 0.02) by 1.5, 1.45, and 2.6 h for DM, OM, and ADF, respectively in steers fed OWB, regardless of DDGS supplementation. Ruminal degradation kinetics were not (P = 0.17) independently affected by DDGS supplementation. Future investigations should elucidate the interaction between supplementation and forage quality. [ABSTRACT FROM AUTHOR]

Presents abstracts of several studies on animal nutrition. "Effects of Phase Feeding of Protein on Performance, Blood Urea N, Manure N:P Ratio, and Carcass Characteristics of Feedlot Cattle," by J. T. Vasconcelos et al; "Influence of Sodium Caseinte Infusion on Voluntary Feed Intake and Digestive Function in Steer Calves Fed a Sudangrass-Based Growing Diet," by E. G. Alvarez and R. A. Zinn; "Feedlot Cattle Responses to Reduced Levels of Degradable Protein," by J. W. Lehmkuhler, S. C. Arp and D. M. Schaefer.

Cattle in a hot climate have 2 peak grazing times, early morning and late afternoon, so feeding a supplement in early morning may interfere with pasture consumption. A controlled-release urea may synchronize ruminal ammonia and energy availability compared with urea. The objective of this study was to evaluate the ingestive behavior of grazing cattle in the dry season at a low latitude, receiving supplements containing urea or Optigen (a controlled-release urea) at 0700 or 1300 h. One hundred twenty young Nellore bulls with BW of 228 ± 39 kg and 12 mo old were used, 5 in each of 20 paddocks of 3 ha each. The pasture was Brachiaria brizantha cv. Marandu. The duration was 98 d, 14 d of adaptation and 3 periods of 28 d. The grazing time and the time at the supplement trough during daytime (0600 to 1750 h), nighttime (1800 to 0550 h), and total were evaluated by trained people at 10-min intervals on 1 d in each period. The 4 treatments were a factorial design of 2 feeding times × 2 urea sources, applied in a randomized complete block design. Statistical analysis was by the MIXED procedure of SAS, version 9.2 (SAS, 2008), considering block as a random variable. There was no influence of supplementation time, urea sources, or their interaction on the grazing time or the trough time during daytime, nighttime or total (P > 0.10). The grazing time was reduced by 92 min (P < 0.01) in the third period compared with the first 2 and the trough time was lower in the first period (33 min; P = 0.03) than in the second (50 min) and the third (65 min), but there were no interactions of period with treatment. These changes are presumably a response to increasing pasture growth as the seasonal rains began. In conclusion, under the conditions of this study, the time of supplementation and the urea sources do not alter the ingestive behavior of young bulls. [ABSTRACT FROM AUTHOR]

To reduce the propensity of alfalfa to cause pasture bloat in grazing animals, researchers sought to transform this popular forage with a bHLH anthocyanin regulatory gene (Lc) from maize. Expression of the Lc (leaf color) gene causes accumulation of anthocyanidin and proanthocyanidins in alfalfa tissues, giving rise to novel 'purple-green' forage. In this study, the effects of Lc expression on ruminal degradation of the forage were studied in vitro. Field-grown parental and three transgenic forages were harvested at the pre-bud stage, freeze-dried and ground (1.0 mm) for use as substrate. Anthocyanidin content in the transgenic genotypes ranged from 130 to 136 μg/g DM. The ground forages (500 mg in F57 bags) were incubated anaerobically for 0, 2, 4, 8, 12, 16, 24, and 48 h in a DAISYII Incubator (ANKOM Technology, Macedon, NY) for determination of DM and N degradabilities (n = 9). A second incubation was conducted (sampling at 0, 4, 8 and 12 h) with 15N included as a marker for microbial protein. Compared to the non-transgenic parental alfalfa (NT), the Lc-transgenic genotypes contained less (P = 0.034) rapidly soluble DM, but their slowly degradable DM fractions, rates of degradation and lag times for digestion were similar (P ≥ 0.122) to NT. At 0 h, the true disappearances of N and DM were lower (P < 0.001 and P = 0.027, respectively) from the Lc genotypes than from NT alfalfa, but they did not differ (P ≥ 0.137) at 4, 8, or 12 h. Solubility of DM and N were both negatively correlated (R2 ≥ 0.563) with the concentration of anthocyanidins measured in the forage. Lc-transformation reduced the initial rate, but not the extent of DM and N digestion of alfalfa in the rumen. These properties could improve the utilization of protein and possibly reduce the risk of bloat in ruminants consuming fresh alfalfa. [ABSTRACT FROM AUTHOR]

This study was carried out to determine rate and extent of DM, CP, NDF and ADF degradation parameter kinetics of Agropyron tauri (ATA), Agropyron trichophorum (ATR), and Bromus tomentellus (BT). Forage samples were collected at the preflowering stage in spring by hand. Dried forage samples were incubated for 0, 6, 12, 24, 48, 72 and 96 h in the rumen of four Varamini wethers. Immediately after submersion of the 0 h bags of substrate into the ruminal fluid, all bags were removed and rinsed with an automatic washing machine. Bags were then freeze dried, weighed and analysed for chemical composition. Data were fitted to non-linear degradation model to calculate effective rumen degradation (ERD), and analysed (DM, CP, NDF and ADF degradability parameters of forages) using GLM proc of SAS (1996) as CRD design. Crude protein contents of ATA, ATR and BT were 123, 72, and 143 g/kg, NDF contents were 604, 638, and 451 g/kg and ADF contents were 348, 378 and 273 g/kg DM, respectively. There were differences (P<0.05) between effective DM, CP, NDF and ADF degradability of these pasture species. The ERD of DM, CP, NDF and ADF for ATA at rumen outflow rate of 0.05/h were 473, 630, 239 and 395 g/kg, for ATR were 393, 498, 331 and 337 g/kg, and for BT were 548, 760, 298 and 237 g/kg, respectively. Constant degradation rate of DM, CP, NDF and ADF for ATA were 6.0, 11.8, 2.7 and 5.7%/h, for ATR were 3.8, 8.6, 5.8 and 3.5 %/h and for BT were 4.2, 10.0, 1.8 and 3.7%/h, respectively. The differences between pasture species in the rate and extent of DM, CP and fiber degradation are likely to lead to major differences in forage intake, therefore these characteristics must be considered as main parameters in developing models and ration formulation of grazing ruminants. [ABSTRACT FROM AUTHOR]