Synergism between ammonia and phenols for Hybomitra tabanids in northern and temperate Canada

Baits for tabanids (Diptera: Tabanidae) were tested in the Northwest Territories (60 °N) and Ontario (45 °N) using Nzi traps. Tests targeted ammonia, phenols/cow urine and octenol. About 200 000 tabanids were captured in 15 experiments with a maximum capture of 4182 in one trap in 1 day. In the Northwest Territories, phenols, urine and octenol were effective single baits for only some species. At both locations, adding ammonia to an unbaited or an octenol-baited trap had no effect on catches. By contrast, catches were increased for several species when ammonia was combined with phenols or urine. In Ontario, including ammonia in various baits increased catches by 1.5- to 3.4-fold relative to octenol alone for three Hybomitra and one Tabanus species. Synergism between ammonia and phenols was clearly demonstrated for the dominant Hybomitra species in Ontario (Hybomitra lasiophthalma), but not for the dominant species in the Northwest Territories (Hybomitra epistates). In five other northern Hybomitra species, baits of ammonia and/or octenol in combination with phenols resulted in a 1.7- to 4.1-fold increase in catch relative to an unbaited trap. Further tests of ammonia as a synergist for biting flies may prove useful in, for example, tsetse, which respond strongly to phenols.

Review: Ammonia emissions from dairy farms and beef feedlots

Hristov, A. N., Hanigan, M., Cole, A., Todd, R., McAllister T. A., Ndegwa, P. and Rotz, A. 2011. Review: Ammonia emissions from dairy farms and beef feedlots. Can. J. Anim. Sci. 91: 1–35. Ammonia emitted from animal feeding operations is an environmental and human health hazard, contributing to eutrophication of surface waters and nitrate contamination of ground waters, soil acidity, and fine particulate matter formation. It may also contribute to global warming through nitrous oxide formation. Along with these societal concerns, ammonia emission is a net loss of manure fertilizer value to the producer. A significant portion of cattle manure nitrogen, primarily from urinary urea, is converted to ammonium and eventually lost to the atmosphere as ammonia. Determining ammonia emissions from cattle operations is complicated by the multifaceted nature of the factors regulating ammonia volatilization, such as manure management, ambient temperature, wind speed, and manure composition and pH. Approaches to quantify ammonia emissions include micrometeorological methods, mass balance accounting and enclosures. Each method has its advantages, disadvantages and appropriate application. It is also of interest to determine the ammonia emitting potential of manure (AEP) independent of environmental factors. The ratio of nitrogen to non-volatile minerals (phosphorus, potassium, ash) or nitrogen isotopes ratio in manure has been suggested as a useful indicator of AEP. Existing data on ammonia emission factors and flux rates are extremely variable. For dairy farms, emission factors from 0.82 to 250 g ammonia per cow per day have been reported, with an average of 59 g per cow per day (n=31). Ammonia flux rates for dairy farms averaged 1.03 g m−2 h−1 (n=24). Ammonia losses are significantly greater from beef feedlots, where emission factors average 119 g per animal per day (n=9) with values as high as 280 g per animal per day. Ammonia flux rate for beef feedlots averaged 0.174 g m−2 h−1 (n=12). Using nitrogen mass balance approaches, daily ammonia nitrogen losses of 25 to 50% of the nitrogen excreted in manure have been estimated for dairy cows and feedlot cattle. Practices to mitigate ammonia emissions include reducing excreted N (particularly urinary N), acidifying ammonia sources, or binding ammonium to a substrate. Reducing crude protein concentration in cattle diets and ruminal protein degradability are powerful tools for reducing N excretion, AEP, and whole-farm ammonia emissions. Reducing dietary protein can also benefit the producer by reducing feed cost. These interventions, however, have to be balanced with the risk of lost production. Manure treatment techniques that reduce volatile N species (e.g., urease inhibition, pH reduction, nitrification-denitrification) are also effective for mitigating ammonia emissions. Another option for reducing ammonia emissions is capture and treatment of released ammonia. Examples in the latter category include biofilters, permeable and impermeable covers, and manure incorporation into the soil for crop or pasture production. Process-level simulation of ammonia formation and emission provides a useful tool for estimating emissions over a wide range of production practices and evaluating the potential benefits of mitigation strategies. Reducing ammonia emissions from dairy and beef cattle operations is critical to achieving environmentally sustainable animal production that will benefit producers and society at large.

Responses of tabanids to Nzi traps baited with octenol, cow urine and phenols in Canada

Cow urine and the two phenols responsible for the attraction of biting flies to cow urine (4-methylphenol, 3-n-propylphenol) were compared with octenol (1-octen-3-ol) as baits for Tabanidae. Relative to an unbaited Nzi trap, catches of the horseflies Hybomitra lasiophthalma (Macquart), Tabanus similis Macquart and Tabanus quinquevittatus Wiedemann (Diptera: Tabanidae) were increased by 1.5-2.6, 1.4-2.0 and 1.4-1.9 times, respectively, whenever a bait included octenol released at either 0.13 mg/h or 1.5 mg/h, regardless of the presence of phenols or urine. Catches were not affected when traps were baited with phenols alone at evaporation rates of 0.38 mg/h (4-methylphenol) and 0.022 mg/h (3-n-propylphenol). Catches of Hybomitra horseflies were increased by 1.5-1.9 times with cow urine and 2.6 times with cow urine + octenol. This bait combination could prove to be particularly useful for Hybomitra horseflies, the common tabanids of northern environments.

Influence of dietary crude protein concentration and source on potential ammonia emissions from beef cattle manure

Emissions of ammonia, as well as other gases and particulates, to the atmosphere are a growing concern of livestock producers, the general public, and regulators. The concentration and ruminal degradability of CP in beef cattle diets may affect urinary and fecal excretion of N and thus may affect ammonia emissions from beef cattle feed yards. To determine the effects of dietary CP concentration and degradability on potential ammonia emissions, 54 steers were randomly assigned to nine dietary treatments in a 3 x 3 factorial arrangement of treatments. Treatments consisted of three dietary CP concentrations (11.5, 13, and 14.5%) and three supplemental urea:cottonseed meal ratios (100:0, 50:50, and 0:100 of supplemental N). Steers were confined to tie stalls, and feces and urine excreted were collected and frozen after approximately 30, 75, and 120 d on feed. One percent of daily urine and feces excretion were added to polyethylene chambers containing 1,550 g of soil. Chambers were sealed, and ammonia emissions were trapped in an acid solution for 7 d using a vacuum system. As the protein concentration in the diet increased from 11.5 to 13%, in vitro daily ammonia emissions increased (P < 0.01) 60 to 200%, due primarily to increased urinary N excretion. As days on feed increased, in vitro ammonia emissions also increased (P < 0.01). Potential ammonia losses were highly correlated (P < 0.01) to urinary N (r2 = 0.69), urinary urea-N (r2 = 0.58) excretion, serum urea-N concentration (r2 = 0.52), and intake of degradable protein N (r2 = 0.23). Although dietary composition can affect daily ammonia losses, daily ammonia emissions must be balanced with effects on animal performance to determine optimal protein concentrations and forms in the diet.

Influence of genotype and diet on steer performance, manure odor, and carriage of pathogenic and other fecal bacteria. III. Odorous compound production1,2

Three beef cattle diets were assessed for their potential to produce odorous compounds from cattle feces excreted during the growing and finishing periods. Eight pens containing 51 steers of varying proportions of Brahman and MARC III genotypes were fed either a chopped bromegrass hay diet or a corn silage diet for a 119-d growing period. After the growing period, all steers were switched to the same high-corn finishing diet (high corn) and fed to a target weight of 560 kg (finishing period). Fecal slurries were prepared from a composite of fresh fecal pats collected in each pen during both periods and incubated anaerobically. In additional flasks, starch, protein, or cellulose was added to the composite fecal subsamples to determine the preferred substrates for fermentation and odorous compound production. The content and composition of the fermentation products varied both initially and during the incubation, depending on the diet fed to the steers. The corn silage and high corn feces had the greater initial content of VFA (381.0 and 524.4 micromol/g of DM, respectively) compared with the bromegrass feces (139.3 micromol/g of DM) and accumulated more VFA than the bromegrass feces during the incubation. l-Lactic acid and VFA accumulation in the high corn and corn silage feces was at the expense of starch, based on starch loss and the production of straight-chain VFA. In the bromegrass feces, accumulation of branched-chain VFA and aromatic compounds and the low starch availability indicated that the protein in the feces was the primary source for odorous compound production. Substrate additions confirmed these conclusions. We conclude that starch availability was the primary factor determining accumulation and composition of malodorous fermentation products, and when starch was unavailable, fecal microorganisms utilized protein.

Influence of canola and sunflower diet amendments on cattle feedlot manure

Cattle (Bos taurus) producers can replace a part of the traditional diet of barley (Hordeum vulgare L.) grain/silage with sunflower (Helianthus annus L.) seeds or canola meal (Brassica napus L.)/oil to enhance conjugated linoleic acids (CLA) content in milk and meat for its positive health benefits. The objective of this study is to investigate the effects of feeding sunflower or canola to finishing steers on cattle manure chemical properties and volatile fatty acid (VFA) content. The control diet contained 84% rolled barley and 15% barley silage, which provided only 2.6% lipid. The other six treatments had 6.6 to 8.6% lipid delivered from sources such as hay, sunflower seed (SS), canola meal/oil, and SS forage pellets. Manure samples (a mixture of cattle urine, feces, and woodchip bedding materials) were collected and analyzed after cattle had been on these diets for 113 d. The dietary source and level of lipid had no effect on organic N and nitrate N content in manure, but significantly affected ammonia N and VFA. Inclusion of SS forage pellets, hay, or canola meal/oil in cattle diets had no significant impact on manure characteristics, but SS significantly reduced the pH and increased propionic, isobutyric, and isovaleric content. In addition, N loss after excretion (mainly from urine N) increases with the pH and N levels in both feed and manure. The combination of SS with barley silage resulted in a lower VFA and NH3 content in manure and should be a more attractive option. To better manage N nutrient cycles and reduce NH3 related odor problems, feed and manure pH should be one of the factors to consider when determining feed mix rations.

Effect of organic matter addition to the pen surface and pen cleaning frequency on nitrogen mass balance in open feedlots

Three finishing trials were conducted to determine the effects of dietary manipulation and management on N losses from open feedlots. In each experiment, 96 steers were assigned randomly to 12 nutrient balance pens. In Trial 1, calves were fed for 180 d during the winter/spring months; in Trial 2, yearlings were fed for 132 d in the summer. In Trials 1 and 2, N losses from pens were compared directly by adding OM to the pen surface or indirectly by feeding digestible ingredients designed to increase OM excretion. The dietary treatment (BRAN) included 30% corn bran (DM basis) replacing dry-rolled corn. Pens where OM was directly added received sawdust applications (SAWDUST) at a rate to match OM excretion from the BRAN diet. These two treatments were compared with a conventional, 75% dry-rolled corn diet (CON). Because CON and SAWDUST diets were identical, performance for both treatments was similar during Trials 1 and 2. The BRAN diet decreased (P < 0.10) gain efficiency during Trials 1 and 2 by 9.5% relative to CON. Fecal N excretion was greater (P < 0.01) for calves and yearlings when BRAN was fed compared with CON. Adding OM to the pen surface increased (P < 0.01) the amount of N in manure removed from pens and reduced (P < 0.10) N losses in Trial 1. Nitrogen losses were not significantly different among treatments in Trial 2. In Trial 3, calves were fed for 166 d during the winter/spring months. A 2 x 2 factorial design was used to evaluate pen cleaning frequency and diets similar to CON and BRAN. Pens were either cleaned monthly or once at the end of the feeding period. Daily DMI was greater (P = 0.01) and ADG was lower (P < 0.01) when cattle were fed BRAN compared with CON. Responses from all three trials indicate a negative effect of BRAN on gain efficiency. Dietary treatment and cleaning frequency interacted for N balance in the feedlot. Nitrogen losses decreased and manure N increased (P < 0.10) for cattle fed BRAN compared with CON when pens were cleaned monthly. Feeding BRAN did not affect total manure N, but resulted in higher N losses when pens were cleaned only once. For all trials, BRAN increased the amount of N remaining in composted manure. Adding OM to pen surfaces and/or cleaning pens more frequently may decrease N losses from open feedlot pens and from compost, although responses seem influenced by ambient temperature or season.

Effects of dietary nitrogen manipulation on ammonia volatilization from manure from Holstein heifers

Decomposition of livestock manure produces gaseous ammonia. Dietary manipulation is one means to reduce N in manure and ammonia volatilization. The effects of dietary crude protein concentration on N intake, N and urinary urea-N excretion, and ammonia volatilization were measured. Eight Holstein heifers (body weight = 260 to 488 kg) were fed a total mixed ration containing either 9.6 or 11.0% crude protein in a crossover design. Oatlage and concentrate were fed at 77:23 (dry matter basis), and soybean meal was used to alter total dietary crude protein. Seven-day adjustment periods preceded 5-d collection periods. Indwelling urinary catheters were inserted 2 d prior to the collection periods. Daily feces and acidified urine were collected, stirred, and subsampled for total Kjeldahl N, urinary urea N, dry matter, P, K, and ash. Urine collection tubes were split during period 2 to allow for collection of unacidified samples for urea N and total N determinations. Unacidified urine and fecal samples were combined (1:1.3) for collection of volatilized ammonia. Remaining slurries were extracted for total and urea N. Increased dietary crude protein concentration increased N intake, N excretion, urea-N excretion, and N excreted in the urine by the heifers. Dietary manipulation of N intake by reduction of 14.0% (dry matter basis) resulted in a 28.1% decrease in ammonia emission and decreases in the urea N, total N, and percentage N excreted in the urine of 29.6, 19.8, and 7.4%, respectively. Ammonia volatilization was dependent on N quantity and form in the urine.