K. M. Wittenberg

Validation of the sulphur hexafluoride (SF6) tracer gas technique for measurement of methane and carbon dioxide production by cattle

Methane (CH4) and carbon dioxide (CO2) production from six crossbred yearling beef heifers (400 ± 13.0 kg) were measured, using the sulphur hexafluoride (SF6) tracer gas technique (Tracer) and open-circuit hood calorimetry (Cal) to validate the former in estimating rumen CH4 and CO2 production in the field. Animals were individually fed a diet consisting of 50% barley concentrate and 50% alfalfa cubes at 1.3 tmaintenance requirements daily. Hifers were divided into two groups for individual animal 24- h gas measurements by each method. Each group of heifers was rotated between the Cal and Tracer techniques for 6 consecutive days in an incomplete block design. Methane production ranged from 108 to 145 L d-1 (mean 130 ± 4.0 L d-1) using the Cal technique, and 90 to 167 L d-1 (mean 137 ± 4.0 L d-1) using the Tracer technique. The mean CH4 production (L d-1) was not different (P = 0.24) between the two methods. Carbon dioxide production with the Tracer technique was 20% higher than CO2 production with ...

Effect of low and high forage diet on enteric and manure pack greenhouse gas emissions from a feedlot

The objectives of this study were to assess enteric methane (CH4) production by beef steers fed one of two isocaloric diets with different forage:grain ratios and to quantify greenhouse gas (GHG) emissions from bedded manure packs in the eight feedlot pens holding these steers (14 head pen-1). Five animals (252 ± 20 kg) in each pen were randomly selected for measurement of CH4 emissions over the course of the 126-d feeding trial. Two 24-h gas collections were completed for each steer in each of three collection periods using the sulfur hexafluoride tracer gas technique. The fluxes of nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) from bedding packs were measured using vented static chambers in each sampling period. Methane production (L d-1) was 42% higher (P < 0.05) from steers fed the low forage:grain ratio than from steers fed the high forage:grain ratio. Overall, methane production (% of gross energy intake) ranged from 0.9 to 6.9% on the low forage:grain diet and from 0.7 to 4.9% on the ...

Evaluating greenhouse gas mitigation practices in livestock systems: an illustration of a whole-farm approach

As agriculture contributes about 0·08 of Canadas greenhouse gas (GHG) emissions, reducing agricultural emissions would significantly decrease total Canadian GHG output. Evaluating mitigation practices is not always easy because of the complexity of farming systems in which one change may affect many processes and associated emissions. The objective of the current study was to compare the effects of selected management practices on net whole-farm emissions, expressed in CO 2 equivalents (CO 2 e) from a beef production system, as estimated for hypothetical farms at four disparate locations in western Canada. Whole-farm emissions (t CO 2 e) per unit of protein output (t) of 11 management systems (Table 2) were compared for each farm using a model based, in part, on Intergovernmental Panel on Climate Change (IPCC) equations. Compared with the baseline management scenario, maintaining cattle on alfalfa-grass pastures showed the largest decrease (0·53―1·08 t CO 2 e/t protein) in emissions for all locations. Feeding lower quality forage over winter showed the greatest increase in emissions per unit protein on the southern Alberta (S.AB) and northern Alberta (N.AB) farms, with increases of 1·36 and 2·22 t CO 2 e/t protein, respectively. Eliminating the fertilization of forages re- sulted in the largest increase (4·20 t CO 2 e/t protein) in emissions per unit protein on the Saskatchewan (SK) farm, while reducing the fertilizer rate by half for all crops showed the largest increase (11-40 t CO 2 e/t protein) on the Manitoba (MB) farm. The findings, while approximate, illustrate the importance of considering all GHGs simultaneously, and show that practices which best reduce emissions may vary among locations. The findings also suggest merit in comparing emissions on the basis of CO 2 e per unit of protein exported off-farm, rather than on the basis of total CO 2 e or CO 2 e per hectare.

Effects of the chop lengths of alfalfa silage and oat silage on feed intake, milk production, feeding behavior, and rumen fermentation of dairy cows.

Effects of chop length (shorter: 6 mm, or longer: 19 mm) of alfalfa silage and oat silage were determined in 16 mid-lactation Holstein cows, 4 of which were rumen cannulated, using a replicated 4 x 4 Latin square design with a 2 x 2 arrangement of treatments. Experimental periods were 21 d long and consisted of 14 d of adaptation and 7 d of sampling. Cows received a total mixed ration containing [dry matter (DM) basis] 42.0% barley grain-based energy supplement, 10% protein supplement, and 24% of DM longer chop or shorter chop alfalfa silage and 24% of DM longer chop or shorter chop oat silage. Rumen pH was measured continuously, and rumen liquid flow rates were determined in rumen-cannulated cows. Feeding behavior was determined by videotaping, and meal patterns were determined by continuously weighing the feed in the bunk of 8 cows. Reducing the chop length of alfalfa silage and oat silage reduced the average geometric particle length from 14.2 to 10.9 mm and from 13.4 to 10.4 mm, respectively. Reducing the alfalfa chop length did not affect feed intake, whereas reducing the oat silage chop length increased DM intake from to 19.4 to 21.2 kg/d. Reducing the chop lengths of alfalfa silage and oat silage chop length did not affect milk production, rumen fermentation, feeding behavior, meal patterns, and blood metabolites. Daily milk yield, milk fat percentage, and milk protein percentage averaged 36.1 kg/d, 3.00%, and 3.16%, respectively, across diets. The low milk fat percentages suggest that the diets induced subacute ruminal acidosis. This was also substantiated by the rumen pH, which was below 5.6 for more than 122 min/d for all diets. The onset of subacute ruminal acidosis despite apparently adequate dietary neutral detergent fiber content and particle size distribution as well as the long duration of chewing might be attributed to sorting against long feed particles.

Use of forage inoculants with or without enzymes to improve preservation and quality of whole crop barley forage ensiled as large bales

Moshtaghi Nia, S. A. and Wittenberg, K. M. 1999. Use of forage inoculants with or without enzymes to improve preservation and quality of whole crop barley forage ensiled as large bales. Can. J. Anim. Sci. 79: 525‐532. The effects of forage additives, applied to bales wrapped at either 2 or 10 h post-baling, on preservation and quality of whole barley crop ensiled as large bal es were investigated. Forage was cut at the early milk stage and allowed to wilt over a 24-h period to 47% DM. Bales were allocate d on the basis of baling sequence to one of three additives treatments: without inoculant (Control); treated with a microbial ino culant, Lactobacillus plantarum and Pediococcus cerevisiae(LpPc); or treated with Lactobacillus plantarum and Pediococcus cerevisiae, plus cellulase and pectinase (LpPcE). An equal number of bales ( n = 18) representing each treatment group were wrapped at either 2 or 10 h post-baling. All bales were core sampled at baling and on days 1, 2, 3, 6, 9, 13, 17, 29, 64, 92, 252 and 308 post-ba ling. Bales were weighed prior to being wrapped and when removed from storage to measure DM and nutrient losses during storage. During wrapping, a thermocouple wire was inserted in each bale to monitor bale temperature. Time of wrapping did not affect nutrient composition or ensiling characteristics of silage. Application of forage additives had no effect on nutrient profile o r recovery, however, silage treated with LpPc inoculant had lower ( P < 0.05) ammonia N compared with untreated or treated with LpPcE silage. Storage temperature of bales representing all treatments did not exceed 28°C but were approximately 2 to 3°C higher in the Control than treated silage for the first 3 d post-ensiling. Silage treated with forage additives had a lower ( P < 0.05) pH and an increase (P < 0.05) in concentrations of lactic and total acids. Ethanol and 2,3 butanediol levels were higher ( P < 0.05) in untreated silage compared with inoculated silage. Silage treated with forage additives were more stable and took 5, 9 and 12 d to heat af ter exposure to air for Control, LpPc and LpPcE silage, respectively. Results from this study indicated that treatment with microbi al inoculants was beneficial in preserving whole crop barley ensiled as large bales. Addition of enzymes to microbial inoculant di d not have further beneficial effect on quality of large bale silage.

Morning vs. evening feed delivery for lactating dairy cows

Nikkhah, A., Furedi, C. J., Kennedy, A. D., Scott, S. L., Wittenberg, K. M. Crow, G. H. and Plaizier, J. C. 2011. Morning vs. evening feed delivery for lactating dairy cows. Can. J. Anim. Sci. 91: 113–122. A study was conducted to investigate the effects of changing feed delivery time from morning (0900) to evening (2100) on feed intake, diurnal feed intake patterns, digestion, rumen fermentation, milk production and composition, as well as on several blood metabolites. Eight (four ruminally cannulated) lactating Holstein cows, consisting of four primiparous and four multiparous cows, were used in the study. The change in the time of feed delivery increased the proportion of feed consumed within 3 h of feed delivery in all cows (54.7 vs. 46.3±4.1%, means±SE, P=0.05), but increased daily dry matter intake only in primiparous cows (18.5 vs. 20.4±0.7 kg d−1, P=0.05). Average daily concentrations of blood glucose, lactate, urea and β-hydroxybutyrate (BHBA) as well as rumen pH and concentrations of volatile fa...

Potential To Reduce Escherichia coli Shedding in Cattle Feces by Using Sainfoin (Onobrychis viciifolia) Forage, Tested In Vitro and In Vivo

ABSTRACT There is a growing concern about the presence of pathogens in cattle manure and its implications on human and environmental health. The phytochemical-rich forage sainfoin (Onobrychis viciifolia) and purified phenolics (trans-cinnamic acid, p-coumaric acid, and ferulic acid) were evaluated for their ability to reduce the viability of pathogenic Escherichia coli strains, including E. coli O157:H7. MICs were determined using purified phenolics and acetone extracts of sainfoin and alfalfa (Medicago sativa), a non-tannin-containing legume. Ground sainfoin or pure phenolics were mixed with fresh cattle feces and inoculated with a ciprofloxacin-resistant strain of E. coli, O157:H7, to assess its viability at −20°C, 5°C, or 37°C over 14 days. Forty steers were fed either a sainfoin (hay or silage) or alfalfa (hay or silage) diet over a 9-week period. In the in vitro study, the MICs for coumaric (1.2 mg/ml) and cinnamic (1.4 mg/ml) acids were 10- to 20-fold lower than the MICs for sainfoin and alfalfa extracts. In the inoculated feces, the −20°C treatment had death rates which were at least twice as high as those of the 5°C treatment, irrespective of the additive used. Sainfoin was less effective than coumaric acid in reducing E. coli O157:H7 Cipr in the inoculated feces. During the animal trial, fecal E. coli numbers declined marginally in the presence of sainfoin (silage and hay) and alfalfa silage but not in the presence of hay, indicating the presence of other phenolics in alfalfa. In conclusion, phenolic-containing forages can be used as a means of minimally reducing E. coli shedding in cattle without affecting animal production.

Comparison of techniques for estimation of forage dry matter intake by grazing beef cattle

Four techniques were compared for their ability to estimate forage dry matter intake (DMI) of grazing animals. In the Cage technique, 10 grazing cages were placed within each pasture, and forage inside and outside the cages was clipped from 0.25-m2 quadrats after 12 to 20 d of grazing. The difference between forage inside and outside the grazing cage represented forage consumed by grazing animals. The second technique used n-alkane controlled release capsules to measure DMI of individual grazing animals (N-alkane marker technique). The remaining two techniques were prediction equations; one utilized body weight (BW) and average daily gain (ADG) to estimate DMI (Minson equation) and the other related dietary net energy concentration and BW to DMI (Net Energy equation). The four methodologies were applied to a 3-yr study evaluating liquid hog manure on the productivity of grass pastures. The study utilized steers of a relatively uniform body size on six continuously grazed grass pastures. When individual an...

Enteric methane emissions from backgrounded cattle consuming all-forage diets

To quantify enteric methane (CH4) emissions of growing cattle consuming allforage diets, a field study utilizing 144 British × Continental crossbred steers (262 ± 4 kg) was conducted during an 84-d overwintering period followed by a 56-d grazing period in one of two, grass-based pastures. Enteric CH4 emissions were quantified using the sulphur hexaflouride (SF6) tracer gas technique. During the overwintering period, four qualities of chopped alfalfa-grass silage, ranging in NDF content from 46.4 to 60.8%, DM basis, were utilized. Steers fed the lowest quality forage (60.8% NDF) had lower DMI, (6.8 ± 0.4 kg head-1, P = 0.0075) and lower ADG (0.83 ± 0.03 kg d-1, P = 0.0028) compared with those fed higher quality forage whose intake ranged from 8.2 to 9.1 ± 0.4 kg d-1, with gains ranging from 1.00 to 1.06 ± 0.03 kg d-1. Enteric emissions (% GE intake) were not influenced by forage quality across this range of NDF values; however, CH4 losses did decrease from 6.8 to 4.7 ± 0.3% GE intake as the winter period p...

Chitin analysis of hay as a means of determining fungal invasion during storage

An ion-exchange chromatography method was tested for quantification of fungal invasion in alfalfa forage. The concentration of chitin, an N-acetyl-D-glucosamine polymer found in spore and mycelium cell walls, was measured to quantitate the degree of forage fungal invasion. Chitin concentrations ranged from 1.583 to 7.530 g kg−1 DM in the alfalfa forage. Stored hay chitin concentration can be influenced by standing crop and harvesting conditions as well as hay moisture content at the time of stacking. Chitin concentrations at the time of stacking and after 60 days storage were: 6.26 ± 0.12 and 6.85 ± 0.12; 2.69 ± 0.16 and 3.57 ± 0.12; 2.50 ± 0.12 and 3.95 ± 0.12 g kg−1DM for hay baled at 14.8, 21.5 and 29.1% moisture, respectively. High chitin concentrations for hay baled at the lowest moisture level reflected post-cutting fungal and bacterial invasion of forage exposed to precipitation while lying in a swath. Pre-storage fungal invasion for hay baled at the lowest moisture level resulted in a negative correlation between post-storage chitin concentration and visual mold assessment. Alfalfa hay containing 14.8, 21.5 and 29.1% moisture at the time of stacking had 9.6 ± 5.9, 33.7 ± 7.3 and 60.9 ± 5.9% increases in chitin concentration during a 60-day storage period. Change in chitin concentration during storage was positively correlated (P < 0.01) with visual mold scores of hay removed from storage and negatively correlated (P < 0.05) with dry matter retention during storage.