bluuebunny/crossref_metadata_2025 huggingface dataset:
CONTROL OF GRASSHOPPERS, PARTICULARLY HIEROGLYPHUS DAGANENSIS, IN NORTHERN BENIN USING METARHIZIUM FLAVOVIRIDE
Authors: Lomer C.J. , Thomas M.B. , Douro-Kpindou O.-K. , Gbongboui C. , Godonou I. , Langewald J. , Shah P.A.
Published: April 2011

Trials on the use of Metarhizium flavoviride Gams and Roszypal conidia in oil-based formulation for the control of grasshoppers, particularly Hieroglyphus daganensis Krauss, in Malanville, north Benin, are described. Preliminary work examined sprayer types, application rate, and time of application. In a trial on 4-ha plots with three replicates, M. flavoviride mycoinsecticide application to H. daganensis nymphs resulted in field population reductions of 70% after 14 days. In samples incubated in cages, mortality was higher in the samples taken 3 or 7 days after application than in the sample taken immediately after application, indicating the possibility of residual pick-up compared with direct spray impact in this environment. Significant mortality was still being observed in samples collected 37 days after application; to investigate this further, a method for bioassaying the spore load in the field was developed and used to monitor the spore load in the field. The possibility that the results indicate the occurrence of secondary infections resulting from horizontal transmission of M. flavoviride is discussed.
ATTEMPTS TO INCREASE THE PREVALENCE AND SEVERITY OF INFECTION OF GRASSHOPPERS WITH THE ENTOMOPATHOGEN NOSEMA LOCUSTAE CANNING (MICROSPORIDA: NOSEMATIDAE) BY REPEATED FIELD APPLICATION
Authors: Johnson Dan L. , Dolinski Michael G.
Published: April 2011

Initial promising results with the microsporidium Nosema locustae Canning as a means of controlling grasshoppers have been followed by some cases of limited field performance. However, at sublethal doses this entomopathogen can reduce grasshopper feeding, reproduction and development, suggesting that the damage caused to range, forages and crops might be reduced if the prevalence of infection in the field could be increased over previously achieved levels. In a field experiment, we treated plots totalling 780 ha with bran bait containing N. locustae at either 2.5 or 5.0 × 109 spores per ha in each of two consecutive years, and grasshopper populations and the prevalence and degree of infection were monitored every two weeks during the summers, for three years. Little or no background infection occurred in the untreated plots. Infections of grasshoppers with N. locustae in the treated plots during the first year of application, typically increased from less than 5% by the 4th week to 10–15% by the 8th week after application. The higher application rates resulted in only slightly higher percentages infected. Most of the infections were classified by microscopic examination as trace to moderate, although heavy infections were observed in the second year. Up to 35% of some Melanoplus species collected from the treated plots were found to contain N. locustae spores, but intensive monitoring indicated population reductions that were inconsistent among sites and generally less than 50%. Other species, notably Aeropedellus clavatus, Ageneotettix deorum, Bruneria brunnea and Camnula pellucida, failed to acquire significant infection by N. locustae. The presence of these apparently less susceptible species did not account for the poor overall performance of the treatments. Two annual applications of N. locustae did not greatly increase the rate or severity of infections in grasshopper populations, although at one of the three sites, trace infections were found in the treated plots six years later.Although Nosema may eventually have value as a component of an integrated grasshopper pest management system, the low virulence cannot be readily overcome by repeated applications.
Larvae of the North American Olethreutidae (Lepidoptera)
Authors: MacKay Margaret Rae
Published: April 2011

The late-instar larvae of about 185 species of the North American Olethreutidae are described and most of them illustrated. Included in these are many pests, such as Grapholitha molesta, Carpocapsa pomonella, and Spilonota ocellana on fruit trees, Paralobesia viteana on grapes, Ancylis comptana fragariae on strawberries, Laspeyresia nigricana in pea pods, Laspeyresia caryana in hickory and pecan nuts, Taniva albolineana in spruce needles, and species of Rhyacionia and Petrova on pines. Keys to species groups and to individual species are provided. Of the diagnostic and specialized characters listed, the most useful include the setae, the spinneret, and the shape of the larva, especially of its head and anal shield. The main characters are given for the postulated ancestral larva and for the highly developed larva. Most of the species groups are arranged according to the suggested phylogenetic relationship of their larvae, emphasizing the necessity of a revision of the family. Larvae of some genera previously difficult to classify, such as Pseudogalleria and Hystricophora, indicate the relationship of those genera to other groups; conversely, lack of relationship is clearly shown in other instances, e.g., between Carpocapsa pomonella and Carpocapsa saltitans, and between the two species Epiblema culminana and E. suffusana and other members of the genus Epiblema.
Potential for range expansion of mountain pine beetle into the boreal forest of North America
Authors: Safranyik L. , Carroll A.L. , Régnière J. , Langor D.W. , Riel W.G. , Shore T.L. , Peter B. , Cooke B.J. , Nealis V.G. , Taylor S.W.
Published: April 2011

The potential for mountain pine beetle, Dendroctonus ponderosae Hopkins (Coleoptera: Curculionidae: Scolytinae), to expand its historical range in North America from west of the continental divide into the eastern boreal forest was assessed on the basis of analyses of the effects of climate and weather on brood development and survival, and key aspects of the interaction of mountain pine beetle with its hosts and associated organisms. Variation in climate suitability and high host susceptibility in the boreal forest create a finite risk of establishment and local persistence of low-level mountain pine beetle populations outside their historical range. Eventually, these populations could become widespread and cause epidemic infestations, creating an ecological pathway eastward through the boreal forest. Such infestations would reduce the commercial value of forests and impose an additional disturbance on native ecological systems.
Influence of plant-hardiness zone, shoot length, and crown class on the incidence of gouting by the balsam woolly adelgid on balsam fir
Authors: Guillet Bertrand , Morrison Andrew , Carleton Drew , Ostaff Don , Quiring Dan
Published: April 2011

We collected midcrown branches of balsam fir, Abies balsamea (L.) Mill. (Pinaceae), at six different sites located in five different plant-hardiness zones, along a north–south transect in New Brunswick, Canada, to evaluate the effect of plant-hardiness zone, crown class (overstory versus understory), and shoot length during the previous 10 years on the annual incidence of gouting by the balsam woolly adelgid, Adelges piceae (Ratzeburg) (Homoptera: Adelgidae). Site, crown class, and their interaction, along with the square of shoot length, explained 78% of the variation in gouting. Variations in gouting attributed to plant-hardiness zone were probably primarily due to variation in mean January temperature: at each site, the mean January temperature was positively and closely related to the mean level of gouting. The level of gouting was consistently higher on trees in the understory than on those in the overstory. Shoot length was parabolically related to the proportion of shoots with gout. The parabolic relationship between shoot size and the level of gouting is similar to that previously reported for galling adelgids, and suggests that gouting by A. piceae may be greatest on trees with an intermediate growth rate.
Controlling life stages of Tribolium castaneum (Coleoptera: Tenebrionidae) in stored rye using microwave energy
Authors: Vadivambal R. , Jayas D. S. , White N. D. G.
Published: April 2011

A pilot-scale industrial microwave unit operating at 2450 MHz was used to test whether microwave treatment can control Tribolium castaneum (Herbst) populations infesting stored rye, Secale cereale L. (Poaceae). Tests were performed in samples of rye (50 g) with 14%, 16%, or 18% moisture content. Samples containing T. castaneum eggs, larvae, pupae, or adults were exposed to 200, 300, 400, or 500 W for periods of 28 or 56 s, resulting in final surface temperatures ranging from 47.2 to 83.9 °C. Eggs were most vulnerable; adults were least vulnerable. Subsequent tests showed that microwaves reduced rye germination and flour yield. No effect of treatment on grain protein content, falling number, sodium dodecyl sulfate sedimentation volume, mixograph and farinograph dough development times, or baking properties was detected.
No support for fluctuating asymmetry as a biomarker of chemical residues in livestock dung
Authors: Floate Kevin D. , Coghlin Paul C.
Published: April 2011

Fluctuating asymmetries (FAs) are small random deviations between left- and right-side measurements of normally symmetrical traits in a given organism. Changes in FA have frequently been proposed as biomarkers for organisms exposed to stress during development and may have value for detecting low levels of chemical residues or other stressors in the environment. We tested this hypothesis in three replicated laboratory experiments and failed to find any effect of chemical residues (ivermectin) in cattle dung on levels of FAs (wing and leg traits) for the dung-breeding flyScathophaga stercorariaL. (Diptera: Scathophagidae). In trying to resolve this discrepancy with previous reports, we found that many studies failed to replicate measurements of FA traits within an experiment, which increases the likelihood of spurious positive results. Furthermore, experiments were rarely replicated either within or between studies, so the repeatability of positive results has usually gone untested. These issues have been raised by others, but are still not being adequately addressed. Discussions regarding the value of FAs as biomarkers will not advance until this is done.
Triterpenoid saponins synergize insecticidal pea peptides: effect on feeding and survival ofSitophilus oryzae(Coleoptera: Curculionidae)
Authors: Fields Paul G. , Woods Sheila , Taylor Wesley G.
Published: April 2011

The triterpenoid saponins soyasaponin I, dehydrosoyasaponin I, echinocystic acid 3-glucoside, β-escin, glycyrrhizic acid, hederacoside C, and α-hederin were tested alone and in combination with insecticidal PA1b peptide mixtures isolated from peas for their effects on the feeding and survival of a stored-product insect, the rice weevil,Sitophilus oryzae(L.). There were two sources of peptides: a purified extract composed primarily of PA1b peptides and a partially purified extract (C8 extract) that contained mainly peptides and lesser amounts of soyasaponin I, dehydrosoyasaponin I, and other compounds. Dehydrosoyasaponin I, echinocystic acid 3-glucoside, α-hederin, and β-escin were active (causing reduced feeding and increased mortality) when used alone. Soyasaponin I, hederacoside C, and glycyrrhizic acid were inactive when used alone. Purified peptides and C8 extract were active when used alone. The mixtures of the inactive soyasaponin I and the active peptides were as active as peptides alone, even when peptides composed only 10% of the mixture. Similar trends were seen with the mixtures of β-escin and PA1b. In general, the mixtures of saponins and peptides were synergistic. Possible modes of synergistic action are discussed.
2-Phenylethanol: context-specific aggregation or sex-attractant pheromone of Boisea rubrolineata (Heteroptera: Rhopalidae)
Authors: Schwarz Joseph J. , Gries Gerhard
Published: April 2011

Western boxelder bugs, Boisea rubrolineata (Barber), form large aggregations on pistillate boxelder, Acer negundo L. (Aceraceae), host trees with maturing seeds, and cluster on warm, sunlit surfaces prior to overwintering. We have recently shown that B. rubrolineata is attracted to the host-tree semiochemicals phenylacetonitrile and 2-phenethyl acetate. We report results of chemical analyses and laboratory bioassays suggesting that aggregation and sexual communication in B. rubrolineata are mediated by 2-phenylethanol. This compound serves as an aggregation pheromone for females, males, and 5th-instar nymphs in midsummer, and in males it appears to serve as a sex-attractant pheromone in early spring. As an aggregation pheromone, 2-phenylethanol originates from the feces of seed-feeding females and males and (or) the ventral abdominal gland of males. As a sex-attractant pheromone, it originates from the ventral abdominal gland of males that emerge from overwintering diapause. Aggregations of B. rubrolineata in the fall and winter are mediated by other as yet unknown pheromones.
Causes of skin damage to pig carcasses
Authors: Faucitano L.
Published: April 2011

Damage to the surface of the carcass after dehairing is a serious commercial problem, since it decreases the grade and subsequently the value of the carcass. In many countries, the incidence of skin damage on the carcass has not been considered to be a problem with high priority, as it seems to be easily solved by just trimming off the skin. However, the presence of an haematoma in the underlying tissue and its negative influence on meat quality must be taken into account. Some European Union (EU) countries are aiming at reducing the incidence of blemished carcasses in order to safeguard the image of the national pork sector for both domestic and exporting markets. Major factors responsible for the incidence of skin damage on the carcass are fighting among mixed groups of pigs and poor handling during the preslaughter stages. Recognition of the economical impact of these two factors on the slaughter pigs may lead to more welfare-friendly handling systems and to reduction in the practice of preslaughter mixing of animals. Key words: Handling, skin damage, animal welfare, carcass and meat quality, pigs
Comparison of two variants of the Fick principle for estimation of mammary blood flow in dairy cows fed two levels of dry matter intake
Authors: Pacheco-Rios D. , Mackenzie D. D. S. , McNabb W. C.
Published: April 2011

The estimation of the mammary blood flow (MBF) is an important component of studies of the utilization of metabolites by the mammary gland of lactating animals. Although there are several flow meters available to measure MBF by direct contact with the vessels perfusing the mammary gland, their use is limited mainly by the surgical preparation required for their implantation. For that reason, the application of the Fick principle was assessed as a mean to estimate MBF as part of a study on amino acid utilization by the mammary gland in three pasture-fed dairy cows at either ad libitum or restricted dry matter intakes. Two methods based on the Fick principle were assessed, namely, arterio-venous differences of amino acids (methionine: Met or phenylalanine+tyrosine: Phe + Tyr) and tritiated water (TOH). The estimated MBF was not significantly different for the Met and Phe + Tyr methods (average of 8.1 and 8.8 L min–1, respectively). The TOH method yielded a significantly lower (P < 0.05) estimate of blood flow (average of 5.3 L min–1). Using the Met and Phe+Tyr methods, the MBF was lower during the period of dietary restriction compared with the ad libitum treatment (average of 9.4 and 7.5 L min–1, respectively). In contrast, the TOH method resulted in a numerically higher MBF for the restricted group (5.7 vs. 4.9 L min–1). The short sampling period a nd the loss of indicator in the TOH method appear to be a disadvantage for extrapolating the estimated values to balance studies with lactating cows involving longer periods of time. The estimated values obtained using the Met or Phe + Tyr appear to be re presentative of the MBF during the experimental period. Therefore, any of these methods (Met, Phe + Tyr) may be used alone or in combination as an alternative to flow meters in studies of mammary metabolism. Key words: Dairy cows, mammary blood flow, Fick principle
Optical properties of turkey pectoralis muscle affecting detection of connective tissue fluorescence
Authors: Swatland H. J.
Published: April 2011

A dual-channel probe was used to detect fluorescence (excitation 365 nm, emission 400 to 550 nm) and reflectance (550 nm) in turkey pectoralis muscles (n= 157). All fluorescence peaks had matching reflectance peaks, but not vice versa. Thus, some reflectance peaks originated from non-fluorescent structures in the muscle. Electrical impedance was used to assess fluid distribution. Electrical capacitance was correlated (P< 0.01) with areas under probe signals (r= 0.19 for both fluorescence and reflectance). In a subset of samples (n= 45), the reflectance of initially polarized light was used to assess light scattering. Consistent relationships between probe signals and the reflectance of initially polarized light were detected. When polarized light was parallel with the longitudinal axes of muscle fibers, and when the analyzer was parallel with the polarizer, reflectance was correlated (P< 0.01) with the incidence of fluorescence and reflectance peaks (R= 0.58 and R= 0.59, respectively), with mean peak intensity (R= 0.51 and R= 0.49, respectively), and with mean half-peak width (R= 0.48 and R= 0.56, respectively). The spectral distribution of correlations indicated that myoglobin as well as differences in light scattering affected the probe detection of connective tissue fluorescence. Thus, bulk optical properties of muscle affected probe detection of connective tissue fluorescence. Key words: Connective tissue, fluorescence, turkey meat
Effects of altering growth curve and age at photostimulation in female broiler breeders. 1. Reproductive development
Authors: Renema R. A. , Robinson F. E. , Goerzen P. R.
Published: April 2011

An experiment was conducted to evaluate the effect of differences in growth curve and age at photostimulation on carcass traits and ovarian morphology in broiler breeder hens at photostimulation and at sexual maturity. Pullets were grown on one of three growth curves STD (standard), LOW (150 g lighter than STD) and HIGH (150 g heavier than STD), and were photostimulated at either 19 wk of age (19WK) or 21 wk of age (21WK). Weekly blood samples were taken between photostimulation and sexual maturity for determination of estradiol-17β concentration. Twelve birds per interaction were processed at photostimulation for determination of carcass and reproductive morphology, followed by an additional 10 birds per interaction at sexual maturity. Unless otherwise stated, all significance was assessed at the P < 0.05 level.

At photostimulation, the HIGH birds were larger and had more carcass lipid (7.44%) than the LOW birds (6.22%). By sexual maturity, carcass lipid as a percentage of BW was similar among the growth curve groups, as were the weights of most carcass parameters measured relative to BW. The large yellow follicle content of ovaries from LOW, STD, and HIGH birds were not different. Ovaries from HIGH birds had 48.2% of large yellow follicles arranged in multiple sets (large yellow follicles weighing within 1 g) compared to 29.5% in STD birds. Birds photostimulated earlier took longer to lay their first egg after photostimulation (19WK = 41.3 d, 21WK = 35.1 d), although this still occurred at a younger age (19WK = 174.3 d of age, 21W K = 182.1 d of age). The profile of plasma estradiol-17β concentration of the 19WK birds appeared to increase more slowly than for the 21WK pullets. As plasma estradiol-17β concentration will increase at a regular rate once it begins to increase, the flatter summary profile of 19WK pullets may be indicative of a less-uniform response to photostimulation. Based on the BW growth curves used in this trial and data collected at photostimulation and sexual maturity, there was no advantage of early photostimulation, and ovarian morphology may be negatively affected by moderate increases in rearing growth curve. Key words: Broiler breeder, sexual maturity, ovarian morphology, growth curve, body weight
Evaluation of dietary strategies to reduce methane production in ruminants: A modelling approach
Authors: Benchaar C. , Pomar C. , Chiquette J.
Published: April 2011

The objective of this study was to use the modelling approach to assess the effectiveness of different existing nutritional strategies to reduce methane production from ruminants. For this purpose, a modified version of a mechanistic and dynamic model of rumen digestion was used. Simulated strategies included: dry matter intake (DMI), forage to concentrate ratio, nature of concentrate (fibrous vs. starchy concentrate), type of starch (slowly vs. rapidly degraded), forage species (legume vs. grass), forage maturity, forage preservation method (dried vs. ensiled), forage processing, and upgrading and supplementation of poor quality forages (straw). This study showed that mathematical modelling is a valuable tool to evaluate the impact of a given dietary manipulation not only on methanogenesis but also on the metabolism of the whole rumen system. Depending on the nature of the intervention, methane production can be reduced by 10 to 40%. Increasing DMI and the proportion of concentrate in the diet reduced methane production (–7 and –40%). Methane production was also decreased with the replacement of fibrous concentrate with starchy concentrate (–22%) and with the utilization of less ruminally degradable starch (–17%). The use of more digestible forage (less mature and processed forage) resulted in a reduction of methane production (–15 and –21%). Methane production was lower with legume than with grass forage (–28%), and with silage compared to hay (–20%). Supplementation or ammoniation of straw did not reduce methane losses, but had a positive impact on the efficiency of rumen metabolism. The modelling approach demonstrated that reduction of methane production from ruminants is a complex challenge. Implementation of any strategy must take into account the possible consequences on the efficiency of the entire rumen system. Key words: Ruminants, methane reduction, modelling approach
Body condition score and its relationship to ultrasound backfat measurements in beef cows
Authors: Broring N. , Wilton J. W. , Colucci P. E.
Published: April 2011

Spring calving beef cows from two genotypes were used in two different trials to examine the effectiveness of visual scoring systems to predict body condition. In trial 1, data on body condition score and ultrasound backfat measurements were collected at three different stages of the production cycle: dry, nursing and weaning. Scoring was by three different assessors and ultrasonic measurements by one experienced technician. Visual scores were positively but inconsistently related to ultrasound measurements (R2 = 0.14, 0.27 and 0.41 for dry, nursing and weaning times, respectively). In the second trial, two different subjective scoring methods were studied, general condition score based on an overall visual assessment of condition with scores ranging from 1 to 5, increasing in half units, and a specific site score based on visual assessment of condition identified at six specific sites on the animal’s body, with scores ranging from 6 to 30. Differences in scores between levels of experience which were observed with the general method were removed with the specific site method. Precision of estimating ultrasound measurements (R2) was improved from 54% for the general to 64% for the specific site assessment when scoring was by experienced assessors. Visual assessment could be improved by more specific scoring, although for research purposes visual assessment would still be inadequate in measuring condition relative to ultrasonic measurements. Key words: Beef cows, ultrasound measurements, condition scoring
Nutritive value of peas for lactating dairy cattle
Authors: Khorasani G. R. , Okine E. K. , Corbett R. R. , Kennelly J. J.
Published: April 2011

The objective of this study was to determine the nutritive value for lactating dairy cows of peas relative to soybean meal (SBM) and barley. Four Holstein cows (200 ± 23 d in milk), fitted with rumen and duodenal cannulae were assigned to four dietary treatments in an experiment designed as a 4 × 4 Latin square with 21 d in each of the four periods. Cows were fed a diet for ad libitum intake with a 50:50 forage:concentrate ratio (DM basis). Peas replaced SBM at the levels of 0, 33.3, 66.7%, and 100% of the concentrate portion in the four test diets. In the 100% pea-based diet, barley was replaced (at 72.35%) to obtain a similar starch content as the SBM-based concentrate. The forage components of the diets consisted of 25% alfalfa silage and 25% bromegrass silage. Dry matter intake (21.6 ± 0.4 kg d–1) and milk yield were not affected by substitution of peas for SBM and barley. Mean rumen pH decreased linearly (P < 0.01) with increasing level of peas in the diet. Substitution of peas for SBM and barley resulted in a linear increase in the concentration of rumen acetate, butyrate, isovalerate, and valerate (P < 0.01), and had a quadratic effect on caproate. Rumen bacterial yield and duodenal flow of total N were not affected by treatment. Ruminal fermentation characteristics and digestibility of nutrients suggest that the substitution of SBM and barley grain with peas may alter the site and end-products of digestion; however, the substitution had no significant effects on production parameters. Key words: Peas, digestion, rumen fermentation, dairy cows
Ruminal degradability of neutral detergent insoluble protein of selected protein sources
Authors: Mustafa A. F. , Christensen D. A. , McKinnon J. J.
Published: April 2011

Ruminal degradability of neutral detergent insoluble protein (NDICP) for different protein sources was measured using two fistulated cows. Effective degradability of NDICP was highest (P < 0.05) for distillers’ grains, intermediate (P < 0.05) for canola meal heated at 125°C and lowest (P < 0.05) for canola meal heated at 145°C. Results showed variations in ruminal degradability of NDICP between protein sources. Key words: Neutral detergent insoluble protein, ruminal degradability
Meat quality of bison (Bison bison bison) longissimus thoracis et lumborum following very fast chilling
Authors: Janz J. A. M. , Aalhus J. L. , Price M. A.
Published: April 2011

Very fast chilling (VFC; internal muscle temperature of -1°C by 5 h postmortem) was achieved in the longissimus lumborum (LL), but not in the semimembranosus, of lean bison carcasses after only 4 or 6 h of chilling at -35°C. Rigorous chilling caused a shift in moisture loss from carcass cooler shrink to retail drip loss. Sides exposed to VFC conditions had darker LL colour at 24 h postmortem; however, the difference did not persist to 6 d. While chilling for 2 h at -35°C resulted in an increased shear over conventionally chilled samples, the application of VFC for 4 and 6 h decreased mean shear values and resulted in a slight improvement in tenderness consistency. Sensory evaluation panellists noted marginal, non-significant differences. Factors affecting tenderization were the physical prevention of sarcomere shortening due to surface freezing with increased chilling intensity and a contribution from proteolytic enzyme systems over time postmortem. Very fast chilling is an effective means of reducing carcass chilling time while improving tenderness in the LL of lean bison carcasses. Key words: Bison, meat quality, very fast chilling
Effect of lighting on ground beef acceptability
Authors: Barbut S.
Published: April 2011

The effects of incandescent (INC), cool-white fluorescent (FL), and metal halide (MH) light sources on the appearance of medium, lean, and extra lean ground beef meat were investigated. Meat color with INC illumination was preferred (P < 0.05) over that with MH illumination for all meat types, and over FL illumination for extra-lean and medium meats. The majority of the panelists described the meat as red under INC lighting, but brown or dark red under FL and MH lighting. Relative luminance data, collected with a fiber optic probe connected to a photo diode array, demonstrated the reason to be a lack of redness in the FL and MH light sources. Key words: Acceptability, beef, color, hamburger, meat, spectra, sensory
Effect of urea multinutritional molasses block supplementation on liveweight change of yak calves and productive and reproductive performances of yak cows
Authors: Shikui Dong , Ruijun Long , Muyi Kang , Xiaogeng Pu , Yanjun Guo
Published: April 2011

Using three different types of yaks, 30 head of 1-yr-old calves (liveweight 60.7 ± 6.3 kg), 30 head of 2-yr-old calves (97.7 ± 10.2 kg) and 30 head of yak cows (160.2 ± 15.1 kg) were randomly selected from the same yak herds. Each type of yak herd was divided into control (C) and trial (T) groups using a completely randomized design, with 10 and 20 animals in the C and T groups, respectively. The animals in the C group were grazed on natural rangeland, and the animals in the T group were supplemented with urea multinutritional molasses blocks (UMMB), together with grazing on natural rangeland from January to May of 1998. The objective was to determine the effect of UMMB on productive performance of yak calves and yak cows in the cold season. Live weight loss of 1-yr-old calves, 2 -yr-old calves and yak cows was reduced by 1.2, 8.3 and 7.9 kg after UMMB supplementation (P < 0.01). The 1-yr-old calves gained the most in the first month of supplementation, but the 2-yr-old calves and yak cows gained the most both in the first and last supplementation months. Daily milk yield of yak cows increased by 0.21 kg d-1 when the lactating animals were supplemented with UMMB (P < 0.01), although there was no effect (P < 0.01) of UMMB supplementation on hair and downy hair production. Supplementation with UMMB also improved reproductive performance of yak cows, with 8.8 and 30.9% increments in pregnancy rate and newborn weight, respectively. We conclude that the benefit of UMMB supplementation the 1-yr-old calves was not economical, with only 0.3:1 output to input ratio, but supplementation of the 2-yr-old calves and yak cows may be economical, with 1.8:1 and 1.4:1 output to input ratios, respectively. Key words: Productivity, reproductive performance, UMMB supplementation, yak
Effect of diet on odorant emissions from cattle manure
Authors: McGinn S. M. , Koenig K. M. , Coates T.
Published: April 2011

Ammonia loss from livestock manure is of special concern because it contributes to odour, can impact non-targeted environments through atmospheric deposition, and represents a potential loss of available nitrogen in manure used as fertilizer for crop growth. Our study investigated the effect of three barley-based diets on manure composition and the emissions of ammonia and volatile fatty acids (VFA) from beef feedlot manure. The results of our study suggest that the metabolizable protein requirements of heavyweight feedlot cattle (400 to 550 kg) were met when finished on a barley grain and barley silage diet [12.9% crude protein (CP)]. Therefore, the ability to reduce total N content of manure or manipulate the route of N excretion is limited, unless lower protein ingredients, such as corn silage or cereal straw, were incorporated into the diet to lower the basal diet CP concentration. There was no relationship between protein level and animal weight gain in our study. There was a positive relationship (P < 0.05) between level of intake protein and ammonium-N content of the surface-sampled pen manure. However, chamber data suggested that the higher ammonium-N content of manure did not translate to any significant difference in ammonia emissions, although the lowest emission rate for surface manure coincided with the lowest protein level. There was also no significant difference in VFA emission related to diet treatments. Key words: Ammonia, volatile fatty acid, odour intensity, cattle, manure, diet
Use of remote bunk monitoring to record effects of breed, feeding regime and weather on feeding behavior and growth performance of cattle
Authors: Schwartzkopf-Genswein K. S. , Silasi R. , McAllister T. A.
Published: April 2011

Thirty Charolais and 29 Holstein steers (432 ± 30 kg) blocked by weight and breed were randomly assigned to four feedlot pens equipped with radio frequency identification systems in the feed bunks. The systems monitored individual steers’ bunk attendance patterns (time, frequency, and duration of visits). Over four 21-d periods, the steers were offered (two times per day) an 80% barley grain: 20% barley silage diet for ad libitum intake (AL); restricted to 95% of their dry matter intake (DMI); during the previous 21 d; returned to an AL regime for 21 d; then restricted once again (RF). Weather data (air temperature, AT; relative humidity, RH; barometric pressure, BP; and wind speed, (WS) were expected at 1-h intervals throughout the four periods. Steer weights were recorded every 21 d; feed refusals every 7 d. Charolais steers had lower DMI (P < 0.05), higher (P < 0.005) average daily gain (ADG) and were more (P < 0.05) efficient than Holstein steers. Higher daily bunk attendance was recorded for Holstein steers during RF (P < 0.0001), and lowest for Charolais steers during RF (P < 0.0001). Dry matter intake, ADG and feed conversion were higher (v < 0.05) with AL than; with RF. Effects of weather varied with feeding regime and breed. On the AL regime, Charolais steers exhibited larger variation in daily bunk attendance than Holsteins (P < 0.0001) in relation to weather categories AT, RH and BP, but this did not compromise growth performance. Long-term data collection is required to relate the impact of weather on feeding patterns of feedlot cattle over different seasons and in different geographic locations. Key words: Feeding behaviour, feedlot, performance, thermal environment, radio frequency
Incubation and rearing temperature effects on Hsp70 levels and heat stress response in broilers
Authors: Givisiez P. E. N. , Furlan R. L. , Malheiros E. B. , Macari M.
Published: April 2011

Incubation temperature (IT) was changed to evaluate if 6-wk-old birds become more tolerant to heat stress. After 13 d of incubation, 470 eggs were submitted to low (36.8°C), normal (37.8°C) and high (38.8°C) temperatures. At day 7 post-hatching, 144 birds were allocated to three rearing temperatures (48 birds/treatment): control/thermoneutral (35–24°C), high (33–30°C) or low (27–18°C) according to the age of the birds. Hsp70 levels in tissues of birds (1 d and 42 d), stress response (42 d) and performance were evaluated. High IT decreased brain (P < 0.01) and liver (P < 0.01) Hsp70 levels, whereas low IT decreased brain (P < 0.01) but increased heart (P < 0.01) Hsp70 levels in 1-d old chicks. Birds incubated at a low temperature had higher (P < 0.05) feed intake (1-42 d). High rearing temperature decreased feed intake (P <0.01) and liveweight (P <0.01). Colonic temperature was lower in birds incubated at a low temperature (P < 0.05) and higher in birds reared in a high temperature (P < 0.05) before heat stress. Birds reared in low temperature had higher increase in colonic temperature after heat stress (P < 0.05). Tissue Hsp70 levels were differently affected by rearing temperature, which affected broiler performance more than IT. Lower IT seemed to increase the sensitivity of birds to heat stress at market age. Key words: Heat resistance, Hsp70, incubation temperature, rearing temperature
Net flux of folates and vitamin B12 through the gastrointestinal tract of sheep
Authors: Girard C. L. , Rémond D.
Published: April 2011

In Trial 1, three wethers were equipped with ruminal and caecal cannulas, catheters in the right ruminal and caecal veins and a mesenteric artery, as well as blood flow probes around the right ruminal and caecal arteries. Blood samples were collected every 15 min from 30 min before to 60 min after the injection of 9 μmol of folic acid and vitamin B12 per kilogram body weight (BW) in the rumen and after injection of half this dose in the caecum. There was a net release of these vitamins from the rumen shortly after the injection (P < 0.05). In Trial 2, four wethers were equipped with a ruminal cannula, catheters in the right ruminal, mesenteric and portal veins and a mesenteric artery and blood flow probes around the right ruminal and the mesenteric arteries and the portal vein. Blood samples were taken 30 and 60 min before, and 30, 60, 120, 180, 240 and 300 min after the intraruminal injection of 0.32 g of folic acid and 0.98 g of vitamin B12. In Trial 3, blood samples were taken from two wethers previously used in Trial 2, before and 10, 40, 70 and 100 min after the intraruminal injection of 0.32 g of folic acid. These intraruminal injections led to a net release of the vitamins from the mesenteric and portal-drained viscera (P ≤ 0.17) but also from the other gastrointestinal tissues, probably mostly from the duodenum. Therefore, in sheep, the main site of absorption for folic acid is the proximal intestine whereas the absorption of vitamin B12 appears in a more distal part of the small intestine. Key words: Sheep, folic acid, vitamin B12, absorption
Relative bioavailability of phosphorus in low-phytate soybean meal for broiler chicks
Authors: Sands J. S. , Ragland D. , Wilcox J. R. , Adeola O.
Published: April 2011

A 14-d chick bioassay was conducted to estimate the relative bioavailability (RBV) of P in a low-phytate soybean meal (LPSBM) using slope-ratio techniques. A corn-soybean meal basal diet was formulated to supply total P and Ca at 3.3 and 10.5 g kg-1, respectively. Three reference diets were formulated by the addition of 0, 0.5 or 1.0 g kg-1 total P from monosodium phosphate (MSP). Four test diets were formulated by the addition of 0.5 or 1.0 g kg-1 total P from LPSBM or soybean meal (SBM). The additions of MSP, LPSBM, or SBM were made at the expense of corn starch. A diet consisting of the basal diet plus supplemental methionine, lysine, threonine and tryptophan was also included to confirm that response to diets containing LPSBM or SBM was not due to the higher concentration of amino acids in those diets. Each diet was randomly assigned to six replicate cages of four birds. Birds were fed from 1 to 3 wk of age. Body weight gain (P < 0.01) and feed intake (FI, P < 0.05) increased linearly as supplemental dietary P increased from 0 to 1.0 g kg-1 for chicks fed diets containing MSP or LPSBM. Chicks that received the basal P level had the lowest body weight gain and FI. No differences were observed between the basal diet and the amino-acid-supplemented basal diet in any of the response criteria measured indicating that the response to tests was due to the increasing levels of dietary P. Tibia mineral content (TMC) and tibia ash weight (ASH) increased linearly (P < 0.001) in response to supplemental P from MSP, LPSBM and SBM. The RBV for LPSBM and SBM using ASH as the response criteria were estimated at 52 ± 10% and 36 ± 8%, respectively. The RBV for LPSBM and SBM using TMC as the response criteria were estimated at 61 ± 9% and 39 ± 7% , respectively. The RBV of LPSBM was 12 to 16 percentage points higher than SBM depending on the response criteria used for estimating RBV. The results of this study clearly indicate that P from LPSBM is more bioavailable than P from SBM. Key words: Chicks, phosphorus, low-phytate soybean meal, bioavailability, slope-ratio
Effect of select lipids and vitamin E on motility and viability of liquid and cryopreserved boar spermatozoa
Authors: Merkies K. , Bean L. D. , Boehnke K. , Buhr M. M.
Published: April 2011

The objective of this work was to test the ability of membrane-incorporated lipid and antioxidant constituents to improve boar spermatozoa function, particularly after cryopreservation. In exp. 1, fresh boar spermatozoa (one ejaculate from each of five boars) was incubated at 37°C in Beltsville Thawing Solution (BTS) + select lipids with 0 (SL), 1 or 5% vitamin E (SL + E1% or E5%). The fluorescent indicator octadecyl rhodamine (R-18) was included to monitor fusion by flow cytometry. Spermatozoa fused more readily to SL or SL + E1% than SL + E5% (86%a vs. 89%a vs. 77%b, respectively; a, b differ, P < 0.005). In exp. 2, fresh boar spermatozoa (one ejaculate from each of four boars) was incubated with BTS buffer alone (control), or BTS with SL, SL + E1% or SL + E5%, omitting the R-18 dye, and held at 18 °C for 7 d. Overall, viability (measured with SYBR-14/PI) was higher in SL + E (59%a vs. 51%a vs. 69%b vs. 67%b for control, SL, SL + E1%, and SL + E5%, respectively; a, b differ, P < 0.035). Both SL and SL ± E1% increased the percentage of motile spermatozoa (total and progressive) after 3 h of storage (P < 0.05); all treatments had similar motility by 24 h, and 0% motility by 96 h. In exp. 3, boar spermatozoa (three ejaculates from each of three boars) was cryopreserved in BTS (control), SL or SL + E1% using a BF5 extender. Initially at 37° C, SL + E1% increased motility, while viability was similar for all treatments. Spermatozoa fused with SL + E1% had the most motile spermatozoa when cooled to 5°C during processing and after freezing and thawing (P < 0.05); the percentage of viable spermatozoa was similar among treatments. In conclusion, incorporation of SL + E1% into spermatozoa membranes improves motility and/or viability of preserved boar spermatozoa. Key words: Freezing, á tocopherol, swine, membranes
Chitin and chitosan as possible novel nitrogen sources for ruminants
Authors: Fadel El-Seed A. N. M. A. , Kamel H. E. M. , Sekine J. , Hishinuma M. , Hamana K.
Published: April 2011

To evaluate chitin (an acetamido-β-glucan) and chitosan (an N-deacetylated product of chitin) as a novel source of N and energy for rumen microbes, the degradabilities of chitin and chitosan were determined in the rumen of sheep fed Italian ryegrass hay as their sole diet. Chitin was degraded in the rumen of sheep, but the rate of degradation was very slow (0.014 h-1) with 18 h lag time for starting degradation. Chitosan was not degraded in the rumen. Results show that neither chitin nor chitosan are effective sources of ruminant feed. A possible utilization of chitosan may be to protect protein from degradation in the rumen. Key words: Chitin, chitosan, ruminal degradation, sheep
Validating and using the GrassGro decision support tool for a mixed grass/alfalfa pasture in western Canada
Authors: Cohen R. D. H. , Stevens J. P. , Moore A. D. , Donnelly J. R.
Published: April 2011

This paper presents predictions of pasture composition and liveweight gain of steers using the GrassGro simulation model. Predictions are compared with field data measured during a 4-yr experiment at Brandon, Manitoba, in which steers grazed alfalfa (Medicago sativa)/grass (Bromus biebersteinii and Psathyrostachys juncea) pastures at 1.1 and 2.2 steers ha-1 in continuous or rotational grazing systems. The predictions of average daily gain, mean forage mass and botanical composition were found to accurately reflect the field data. Predictions of digestibility and protein were less accurate and reasons for this are discussed. Steers from the field trial were not considered finished for slaughter directly off pasture. GrassGro was used to examine the effects of feeding a barley supplement to the steers while at pasture. The results indicated that all steers could have been finished at pasture. Simulation indicated that supplementation at pasture makes the stocking rate of 2.2 steers ha-1 more attractive because twice the number of steers could be finished with little additional requirement for barley supplement. Further simulations provided information on the effects of climate variations during a 30-yr period (1967–1996) on steer production in both continuous and rotational grazing systems using a range of stocking rates from 1.1 to 5.5 steers ha-1. Key words: GrassGro, decision support, steers, grass, alfalfa, pasture
Effects of dietary urea concentration on performance and health of receiving cattle and performance and carcass characteristics of finishing cattle
Authors: Duff G. C. , Malcolm-Callis K. J. , Galyean M. L. , Walker D. A.
Published: April 2011

Effects of urea concentration for receiving and finishing cattle were examined. In exp.1, 197 newly received beef steers (188 kg) were used, and treatments included 0, 0.5, or 1.0% urea [dry matter (DM) basis] in a 70 or 75% concentrate (steamflaked corn-based) diet. A quadratic response (P < 0.05) was observed for dry matter intake (DMI) of concentrate and total DMI during days 0 to 14 with DMI lower for 0.5% urea. A quadratic (P < 0.10) increase in gain:feed for 0.5% urea was noted during days 15 to 28 and days 0 to 28. Urea concentration did not affect bovine respiratory disease (BRD) morbidity. In exp. 2, 235 yearling beef steers (379 kg) and 126 yearling beef heifers (346 kg) were used to evaluate 0, 0.5, 1.0, 1.5, or 1.75% urea concentrations in a steam-flaked sorghum grain-based diet. Average daily gain (ADG) (1.44, 1.48, 1.51, 1.47, and 1.43 kg for 0, 0.5, 1.0, 1.5 or 1.75% urea, respectively), DMI (9.4, 9.3, 9.6, 9.4, kg and 9.2 for 0, 0.5, 1.0, 1.5 or 1.75% urea, respectively), and gain:feed (0.153, 0.160, 0.157, 0.157, and 0.157 for 0, 0.5, 1.0, 1.5 or 1.75% urea, respectively) did not differ (P > 0.10) among treatments for the overall experiment. No major differences were noted for carcass characteristics. Optimum level of dietary urea for newly received beef cattle fed 70 to 75% concentrate diets is approximately 0.5% of the DM for maximum feed efficiency and added urea concentrations did not alter performance or carcass characteristics to a great extent with steam-flaked sorghum grain-based finishing diets. Key words: Beef cattle, urea, health, performance, carcass quality
Estimation of intake and digestibility of silage by beef steers using a controlled release capsule of n-alkanes
Authors: Charmley E. , Ouellet D. R. , Veira D. M. , Michaud R. , Duynisveld J. L. , Petit H. V.
Published: April 2011

Twelve beef steers were fed a grass-legume silage either ad libitum or at 70% of ad libitum feeding. Intake and digestibility were measured directly or predicted using the alkane ratio technique. The C32 and C36 alkanes were delivered via a controlled release capsule (CRC) in the rumen. Level of feeding had no effect on digestibility (P > 0.05) but dry matter (DM) intake tended to be greater for steers fed ad libitum (P = 0.08). The release of alkanes from the CRC was erratic and 20% greater than expected. This influenced the exogenous to endogenous alkane ratios. Estimates of intake were therefore derived using both the expected and actual (determined from total collection of feces and their alkane analysis) exogenous alkane release rates. Estimated intakes based on the manufacturers’ release rate were underestimated and associated with high standard errors. For cattle fed restricted silage, estimated intakes obtained with C31:C32, C33:C32 and C33:C36 alkane pairs and using actual measured release rates of exogenous markers were associated with lower standard errors and averaged 87, 102 and 103% of actual values, respectively. For ad libitum-fed cattle the corresponding values were 81, 96 and 96% of actual values. There was no significant difference between actual and estimated DM intake when the C33:C32 and C36:C32 alkane pairs were used. The precision of intake estimates using manufacturers release rates for exogenous alkanes was poor, as evidenced by significant discrepancies (P < 0.05 for four of six estimates) between observed and predicted values averaging 2.26 kg or 30% of DM intake. However, when measured exogenous alkane release rates were used, standard errors were reduced and discrepancies for estimates using C33:C32 and C33:C326 were only 0.4 kg or 6% of DM intake. Fecal recovery of C27, C29, C31 and C33 alkanes was 73.4, 92.7, 85.6 and 100%, respectively. Both C29 and C33 gave good estimates of digestibility because of high recovery. Observed and estimated values were not significantly different. It is concluded that exogenous alkane release from CRCs was not satisfactorily consistent. Reliable estimates of intake could only be made if actual release rate was known. Endogenous alkanes can be used for determination of digestibility, provided fecal recovery is known. Key words: Beef, silage, alkane, intake, digestibility