bluuebunny/crossref_metadata_2025 huggingface dataset:
3.2 GROUND SYSTEMS FOR RELEASING TRICHOGRAMMA MINUTUM RILEY IN PLANTATION FORESTS
Authors: Smith S.M. , Wallace D.R.
Published: April 2011

Two systems for releasing the egg parasitoid, Trichogramma minutum Riley, from ground level in forest stands are described: (1) a gridded point-source release using parasitized host eggs attached to cards, and (2) a hand-held leafblower distributing parasitized eggs in bulk. Neither technique affected the emergence of the parasitoids released. Parasitoids emerging from eggs released in bulk had a similar sex ratio, longevity, and fecundity to those not released. Both methods of ground release achieved uniform parasitoid distribution and resulted in levels of parasitism similar to those achieved with aerial releases. Parasitism was greater in the mid- to upper canopy of trees than in the lower canopy. The difficulties associated with each technique and its comparative usefulness in experimental and operational programs are discussed.
NATURAL HISTORY, CLASSIFICATION, RECONSTRUCTED PHYLOGENY, AND GEOGRAPHIC HISTORY OF PYTHO LATREILLE (COLEOPTERA: HETEROMERA: PYTHIDAE)
Authors: Pollock Darren A.
Published: April 2011

The classification of the nine world species of Pytho Latreille is reviewed by study of adult, larval, and pupal stages. Keys are provided for separation of species in these three life stages. Taxonomic changes (senior synonym in brackets) include synonymy of P. fallax Seidlitz 1916 [= P. niger Kirby 1837]; P. americanus Kirby 1837 [= P. planus (Olivier 1795)]; P. deplanatus Mannerheim 1843 is transferred from a junior subjective synonym of P. depressus (Linnaeus 1767) to a junior subjective synonym of P. planus (Olivier 1795). Lectotype designations are provided for the following: P. seidlitzi Blair 1925; P. nivalis Lewis 1888; P. niger Kirby 1837; P. fallax Seidlitz 1916; P. abieticola J. Sahlberg 1875; and P. americanus Kirby 1837. Eight larval stage, and 12 adult stage characters were selected for cladistic analysis. Lacking out-group material, pupal characters were not analysed. Character states were polarized using a generalized out-group composed of the three other genera of Pythinae (all monobasic). Phylogenetic analysis based on these 18 characters suggests four monophyletic species-groups: P. seidlitzi group (P. seidlitzi Blair — North America); P. kolwensis group (P. strictus LeConte – North America, P. kolwensis C. Sahlberg —Fennoscandia and the U.S.S.R., P. nivalis Lewis — Japan); P. niger group (P. niger Kirby — North America, P. abieticola J. Sahlberg — Europe, P. jezoensis Kôno — Japan); P. depressus group [P. planus (Olivier, 1795) — North America, P. depressus (Linnaeus, 1767) — Europe and the U.S.S.R.]. Larval stage synapomorphies are relatively more important in defining the species-groups than are those of the adult stage. The ancestor of Pythidae may have been associated with Coniferae as early as the Jurassic. The common ancestor of Northern Hemisphere Pythinae became isolated upon Laurasia once separation from Gondwanaland occurred near the end of the Jurassic. Two of the species-groups have similar disjunctions in North America, Europe, and Japan. The relatively eastern distributions of the North American member of each suggests that the ancestor of each species-group was Euramerican, and underwent vicariance with the opening of the North Atlantic in the Middle Cretaceous. The present distribution of both species-groups is thought to have been caused by the same vicariant event. The ancestor of the P. depressus group, which is presently circumboreal, was probably widespread and could have been Asiamerican in distribution. In the middle to late Tertiary, evidence suggests that Beringia was covered with coniferous forest, and the ancestor of the P. depressus group probably extended across this land bridge. Final separation between any North American and European/Asian species occurred in the Late Miocene or Pliocene, when a cooling climate made possible the evolution of treeless tundra in the north.
DESCRIPTION OF PARABROCHYMENA, NEW GENUS, AND REDEFINITION AND REVIEW OF BROCHYMENA AMYOT AND AUDINET-SERVILLE (HEMIPTERA: PENTATOMIDAE), WITH CONSIDERATIONS ON NATURAL HISTORY, CHOROLOGICAL AFFINITIES, AND EVOLUTIONARY RELATIONSHIPS
Authors: Larivière Marie-Claude
Published: April 2011

From the endemic New World halyine genus Brochymena, two genera are recognized. New morphological characters at the generic level are described. Parabrochymena, new genus, with Pentatoma arborea Say as type species, is erected to contain 10 taxa formerly included in Brochymena. New combinations are Parabrochymena aculeata (Distant), P. apiculata (Van Duzee), P. arborea (Say), P. barberi barberi (Ruckes), P. barberi diluta (Blatchley), P. cuspidata (Distant), P. enigmatica (Ruckes), P. florida (Ruckes), P. haedula (Stål), and P. poeyi (Guérin-Méneville). Brochymena is redefined with 20 taxa: B. affinis Van Duzee, B. cariosa Stål, B. carolinensis (Westwood), B. chelonoides Ruckes, B. dilata Ruckes, B. exardentia Ruckes, B. hoppingi Van Duzee, B. humeralis Ruckes, B. laevigata Ruckes, B. lineata Ruckes, B. marginella Stål, B. myops Stål, B. parva Ruckes, B. punctata punctata Van Duzee, B. punctata pallida Blatchley, B. pilatei Van Duzee, B. quadripustulata (Fabricius), B. splendida Ruckes, B. sulcata Van Duzee, and B. tenebrosa Walker. Four synonymies are established: B. marginella Stål = B. carolinensis (Westwood); B. pilatei Van Duzee = B. sulcata Van Duzee; B. laevigata Ruckes = B. myops Stål; B. exardentia Ruckes = B. lineata Ruckes. Lectotypes are designated for B. affinis Van Duzee, B. cariosa Stål, B. myops Stål, B. punctata pallida Blatchley, and B. p. punctata Van Duzee. Species groups of Brochymena are characterized, and a key to all taxa is presented for the first time. As appropriate, for each species of Brochymena, the following are provided: citation of original description, synonymies, type material, diagnosis, description, geographical distribution, taxonomic comments, natural history, and illustrations of important structural characters. Chorological affinities are presented and systematic relationships are hypothesized.
Pattern of protein production by mammary epithelial cells cultured on membrane inserts
Authors: Cheli F. , Baldi A. , Dell’Orto V. , Zavizion B. , Politis I.
Published: April 2011

Protein and plasminogen activator (PA) production by bovine mammary epithelial cells cultured on inserts and the effect of calcium were studied. The cells cultured on inserts coated with a bovine extracellular matrix established a stable trans-epithelial resistance, and secreted apically αs1-casein and PA. Extracellular calcium increased (P < 0.01) αs1-casein and total proteins, but not PA activity. Key words: Bovine mammary epithelial cells, inserts, differentiation
The effect of storage of cereal grain and enzyme supplementation on measurements of AME and broiler chick performance
Authors: Scott T. A. , Pierce A. B.
Published: April 2011

There is a concern that feeding newly harvested cereal grain results in poor performance in poultry. A broiler chick apparent metabolizable energy (AME) bioassay was used to measure changes in feeding value of wheat (n = 14), hulless (n = 10) and hulled (n = 14) barley with or without a commercial enzyme appropriate for wheat- or barley-based diets. In the broiler chick bioassay, four pens of six male broiler chicks were fed ad lib, from 4 to 17 d, diets containing 80% of a test cereal grain and a high-protein basal mixture containing 1% “celite” as an acid-insoluble ash marker. Each of the cereal-grain-based diets, with or without enzyme, was tested within 3 mo of harvest and again 6 mo later.

With cereal grain storage there were consistent (P < 0.05) increases in feed intake (FI) between 4 and 17 d and body weight (BW) at 17 d of age with wheat-based diets fed wit h (12.5 and 16.9%, respectively, for FI and BW) or without (16.1 and 22.7%) enzyme. In hulless barley diets without enzyme, there was a significant improvement in BW (7.5%) with storage, while storage had a significant effect on FI and BW (2.9 and 6.3%, respectively) when fed with enzyme. For all other barley diets there was a positive effect of storage on FI and BW, but it was not significant. Feed conversion ratios decreased marginally (P > 0.05) with storage of cereal grain. AME of diets was improved within each period by enzyme supplementation. However, there were measurable decreases (P < 0.05) in AME with storage of cereal grains for the three cereal grains with enzyme supplementation (ranging from –3.2 to –8.2%). The r2 of the above measurements for the different sources of cereal grain between storage periods ranged from 0.65 to 0.94, indicating that the relative ranking of the cereal grains, with respect to feeding value, remained similar during storage. Increases in FI with storage were not significantly related to the attempts of the broiler chicks, to maintain metabolizable energy (ME) intake. Therefore, this increases our concerns that “factors” in newly harvested cereal grains may exist and that they may limit voluntary feed intake and/or growth. Key words: Cereal grain storage, AME, broiler performance, wheat, barley
Determination of the methionine requirement of finishing double-muscled Belgian blue bulls with a three-step method
Authors: Froidmont E. , Beckers Y. , Théwis A.
Published: April 2011

A three-step technique was used to determine total amino acids (AA) and the first limiting AA requirements in finishing double-muscled Belgian Blue (dmBB) bulls. In a first experiment, three dmBB bulls (505 ± 21 kg) received a low metabolizable protein diet containing 25% meadow hay and 75% concentrate. Net energy supply was adequate for maximizing daily gains because of continuous infusion of dextrose into the duodenum. The intestinal apparent disappearance of essential AA (EAA) averaged 70.8% and was the lowest for histidine (61.3%) and the highest for arginine (79.9%). In a second experiment, four dmBB bulls (517 ± 16 kg) received the same diet supplemented with duodenal infusion of dextrose and four doses of Na-caseinate (17, 33, 50 and 66% of metabolizable dietary AA) in a 4 × 4 Latin square design. Nitrogen retention for the basal diet alone and the four increasing supplements of Na-caseinate averaged 61, 64, 74, 75 and 78 g d–1, respectively. A supply of 720 g d–1 of metabolizable AA was defined as optimising the N utilization for animal growth. Based on patterns of plasma concentrations, methionine and phenylalanine were probably the limiting AA. In a third experiment, five dmBB bulls (513 ± 60 kg) fed the basal diet received duodenal infusion of dextrose and AA, equivalent to the second dose in exp. 2 except for the supply of metabolizable methionine (12.8, 15.1, 17.6, 20.1, 22.6 and 25.1 g d–1) that varied in a 6 × 6 Latin square design with one missing animal. On the basis of N retention, the metabolizable methionine requirement was estimated to 22.8 g d–1 and corresponded to 360 mg of metabolizable methionine per gram of N retained. Key words: Ruminant, amino acid, duodenal infusion, requirement, plasma, nitrogen pollution
Effects of feeding high energy or high energy-protein diets to goats
Authors: Goonewardene L. A. , Okine E. , Patrick N. , Patrick D. , Day P. A. , Scheer H. D. , Suleiman A.
Published: April 2011

Growth, efficiency and carcass traits were evaluated for goats fed barley or a concentrate mix (CM). Goats on the CM showed higher (P < 0.01) average daily gain (ADG) (27.5%), end of test weight (11.6%), hot carcass weight (HCW) (14.9%) and rib-eye area (REA) (14.7%), lower (P < 0.02) concentrate to gain ratio (CG) ratio (22.5%) and no differences (P > 0.05) in concentrate intake (CI) and dressing percent (DP), compared to those on barley. Although feeding the CM improved ADG, CG, HCW and REA, it may be relatively more economical to finish goats on whole barley grain. Key words: Goat, high energy, high protein, growth, rib-eye area
Recursive systems model of fetal birth weight and calving difficulty in beef heifers
Authors: Tozer P. R. , Scollard D. L. , Marsh T. L. , Marsh T. J.
Published: April 2011

The purpose of this study was to use readily available information, including dam pelvic width (PW) and height (PH) and the fetal coronet band (CB) measurement to predict the calving difficulty (CD) score of first-calf heifers under commercial ranch conditions. Data were collected from a cow-calf ranch over a 3-yr period. Using a recursive system of equations, two models were estimated. First, a linear model was used to predict birth weight (BTW) based on the fetal CB measurement. Second, an ordered logit model was used to predict calving difficulty score based on a nonlinear relationship with birth weight, pelvic dimensions of the dam, and interaction terms. The linear model demonstrated that BTW could be predicted using the CB measurement, both the intercept and slope coefficients were significant at P < 0.001. The model R2 was equal to 0.57 and the standard error of the predicted birth weight was 2.77 kg. The ordered logit model correctly predicted 468 of 684 (68.4%) of the CD scores. The results of this research suggest that it is possible to predict dystocia or calving difficulty on a case-by-case basis with information that is available to ranchers or ranch managers early in the parturition process. The management technique presented has been successfully adopted by some large-scale cow-calf operations, thus the results have commercial applications for beef producers. Key words: Dystocia, heifers, beef, recursive systems, ordered logit, coronet band, birth weight
Effects of barley silage of different theoretical cut length on digestion kinetics in ruminants
Authors: Soita H. W. , Christensen D. A. , McKinnon J. J. , Mustafa A. F.
Published: April 2011

Two studies were conducted to determine the effects of two theoretical lengths of cut (TLC) (short = 4.7 mm and long = 18.8 mm) on the feeding value of barley silage to steers fed an all-forage diet. In the first study, six steers were used to determine intake of dry matter, total tract digestibility of dry matter (DMD), neutral detergent fiber (NDFD), and acid detergent fiber (ADFD) in a replicated switchback design. In the second study, six steers equipped with rumen cannulas were used to determine the effects of barley silage particle size on ruminal kinetic and fermentation parameters. Feeding short barley silage to steers increased (P < 0.05) dry matter intake (DMI), DMD, NDFD, and ADFD compared with feeding long barley silage. The results of the second study showed that reducing barley silage particle size decreased (P < 0.05) ruminal retention time and increased (P < 0.05) passage rate of particulate matter. Ruminal pH was lower (P < 0.05) at 1000, 1200, 1800, 2000, and 2200 h for steers fed the short barley silage compared with those fed the long barley silage. However, the effects of barley silage particle size on ruminal ammonia nitrogen and volatile fatty acid (VFA) concentrations were minimal. Eating rate was similar in both dietary treatments (average 40.3 g min-1). However, steers fed the long silage produced more (P < 0.05) saliva per kg DMI compared with those fed the short barley silage diets. It was concluded that reducing TLC of barley silage increased feed intake and improved total tract utilization of cell wall components by steers. Results of the metabolism study also showed changes in fermentation parameters, but no adverse physiological changes were noted when cattle were fed all forage diets. Key words: Barley silage, particle size, fermentation patterns
Additivity of apparent ileal and fecal phosphorus digestibility values measured in single feed ingredients for growing-finishing pigs
Authors: Fan M. Z. , Sauer W. C.
Published: April 2011

Two experiments were conducted to determine apparent ileal and fecal P digestibility values in barley, wheat, peas and canola meal and to examine whether the apparent P digestibility values measured in single feed ingredients are additive when used in diet for mulation for growing-finishing pigs. In both experiments, five barrows, with average initial body weights of 40 and 35 kg, were fitted with a simple T-cannula at the distal ileum and fed five diets according to a 5 × 5 Latin sq uare design. In exp. 1, the barrows were fed five diets (diets 1, 2, 3, 4, and 5) formulated to contain five graded levels of barley (0, 22.5, 45.0, 67.5 and 90%, respectively) and canola meal (42.7, 36.6, 30.5, 24.4 and 0%, respectively). In exp. 2, the barrows were fed five diets (diets 1, 2, 3, 4, and 5) formulated to contain five graded levels of wheat (88.5, 66.4, 44.3, 22.1 and 0%, respectively) and peas (0, 16.8, 33.6, 50.4 and 67.1%, respectively). Chromic oxide (0.4%) was used as a digestibility marker in both experiments. The pigs were fed twice daily, at 0800 and 2000. The dietary allowance was 1800 g d-1. Each experimental period lasted 8 d. Representative fecal samples were collected during days 5 and 6. Ileal digesta were collected for a total of 24 h, at 2-h intervals, during days 7 and 8. The ileal and fecal P digestibility values in barley, wheat, peas and canola meal were associated with large standard errors, suggesting a large variability within each feed ingredient. There were no differences (P > 0.05) between the directly determined and predicted apparent fecal P digestibility values in diets 2, 3 and 4 of exp. 1. However, there were differences (P < 0.05) between the directly determined and the predicted apparent fecal P digestibility values in diets 3 (46.5 ± 1.0 vs. 38.7 ± 0.6) and 4 (48.2 ± 1.2 vs. 41.6 ± 1.2) in exp. 2, indicating that apparent fecal P digestibility values are not always additive in diet formulation. It is concluded that apparent P digestibility values are variable and not very reliable in diet formulation for swine. Key words: Phosphorus, digestibility, feeds, pigs
Humoral and cellular immune responses of piglets after castration at different ages
Authors: Lessard M. , Taylor A. A. , Braithwaite L. , Weary D. M.
Published: April 2011

In this study, growth of piglets and their humoral and cellular immune responses were used to evaluate the effect of castration at different ages. Piglets (n = 84) from 14 litters were assigned to one of the six treatments: castration or sham-castration at 3, 10 or 17 d of age. An injection of bovine serum albumin (BSA) was given on the day of castration and a second one 14 d later. Blood samples were taken at different times to evaluate the antibody levels against BSA and lymphocyte blastogenesis responses to concanavalin A (Con A), phytohaemagglutinin (PHA) and pokeweed mitogen (PWM). The age of piglets at the first immunization significantly influenced (P < 0.0001) the ability to raise antibodies to the injected antigen. Three-day-old piglets developed weaker antibody response than those immunized at 10 or 17 d of age. Ten- and 17-d-old castrated piglets tended to develop weaker secondary antibody responses than sham-castrated piglets, while those castrated and sham-castrated at 3 d of age did not differ in their antibody response (interaction castration × age; P < 0.08). The fluctuation in lymphocyte blastogenesis response between days 21 and 35 was numerically greater in castrated than in shamcastrated piglets. Ratios between days 35 and 21 of PWM proliferative indexes were significantly higher (P < 0.05) in piglets castrated at 10 or 17 d of age than in sham-castrated piglets. The results indicate that castration of piglets at 10 d of age or older impairs antibody response to BSA and modulates piglet lymphocyte responses to mitogens. Castration at 3 d of age had no marked effect on antibody response and lymphocyte proliferation. Thus castration appears to be less disruptive to immune response if performed at three days of age compared to 10 d of age or older. Key words: Castration, stress, antibody formation, lymphocytes, pigs
A terminal-sire index for selecting rams
Authors: Tosh J. J. , Wilton J. W.
Published: April 2011

A terminal-sire index for selecting rams was developed. It combines genetic evaluations for growth traits and carcass characteristics measured ultrasonically on live animals into a single criterion. Weightings for component traits are averages from the indexes of four slightly different breeding goals, determined using economic values and parameters from the literature. The weightings for breeding values of component traits are -1.45 for birth weight, +1.86 for weight at 50 d of age, +2.27 for gain from 50 to 100 d, -0.51 for ultrasonic fat depth, and +1.36 for ultrasonic loin muscle depth, in phenotypic standard deviation units. Selection that is based on the index will increase growth while simultaneously decreasing fat and increasing muscle. Key words: Breeding strategies, carcass characteristics, growth, selection, sheep
The relationships of fat thickness and muscle depth with grade yield in pork carcasses
Authors: Fortin André
Published: April 2011

Under the Canadian pork grading system, grade yield, a function of fat thickness and muscle depth, is estimated from a prediction equation derived from a national sample. Data from the 1992 National project (Québec, n = 306; Ontario, n = 306; Alberta, n = 262) are used to examine the relevancy of a national sampling on these relationships. Regional origin did not have an effect (P > 0.05) on the relationship of grade yield with fat thickness whereas it did (P < 0.05) for the relationship with muscle depth. Key words: Canada pork grading, grade yield , fat thickness, muscle depth, sampling
Association of a single nucleotide polymorphism in the bovine leptin gene with feed intake, feed efficiency, growth, feeding behaviour, carcass quality and body composition
Authors: Nkrumah J. D. , Li C. , Basarab J. B. , Guercio S. , Meng Y. , Murdoch B. , Hansen C. , Moore S. S.
Published: April 2011

Leptin is a 16-kDa-hormone product of the obese gene synthesized and expressed predominantly by adipose tissues, which has been shown to play major roles in the regulation of body weight, feed intake, energy balance, fertility, and immune system functions. We report an investigation into the association of a previously identified cytosine to thymine missense mutation in exon 2 of the bovine leptin gene with feed intake, feed efficiency, growth, feeding behaviour, carcass quality and body composition in five genetic selection lines of a commercial population of beef cattle. Differences among genotypes in growth, feed intake and feed efficiency were not significant (P > 0.10) though steers homozygous for the thymine allele had positive residual feed intake (i.e., consumed more feed than expected) (+ 0.19 kg d-1) whilst steers homozygous for the cytosine allele had negative residual feed intake (-0.18 kg d-1). Steers carrying the thymine allele had a higher rate of gain in ultrasound backfat (P = 0.02), ultrasound backfat thickness (P = 0. 06), higher carcass grade fat (backfat) (P = 0.005), lower yield grade (P = 0.01) and lower lean meat yield (P = 0.007). The thymine allele also tended to be associated with higher loin subcutaneous fat (P = 0.07) and was associated with higher brisket subcutaneous fat (P = 0.01), and brisket body cavity fat (P = 0.0001). No associations were found among the different genotypes and real-time ultrasound marbling, ultrasound longissimus thoracis area, carcass marbling and carcass longissimus thoracis area (P > 0.10). Our results show that animals carrying the thymine allele versus the cytosine allele may produce carcasses with poorer grades and lower lean meat yields but do not differ in carcass marbling or other fat depots. Key words: Beef cattle, leptin, feed intake, carcass merit
Effects of feed carbohydrates with contrasting properties on rumen fermentation and methane release in vitro
Authors: Hindrichsen I. K. , Wettstein H. -R. , Machmüller A. , Soliva C. R. , Bach Knudsen K. E. , Madsen J. , Kreuzer M.
Published: April 2011

The RUSITEC system was used to test eight diets where the supplements differed in their main carbohydrate source. The forage-to-supplement ratio was 1:1. The eight feeds characterizing the supplements by specific carbohydrates were oat hulls (modeling lignified fiber), soybean hulls (non-lignified fiber), apple pulp (pectin), sugar beet pulp (hemicelluloses and pectin), guar gum (galactomannan), Jerusalem artichoke tubers (fructan), molasses (sucrose), and wheat (starch). Supplements were iso-energetic and iso-nitrogenous. The dietary carbohydrate fractions were analyzed in detail with a combination of enzymatic and chemical methods. The methane release (mmol g-1 degraded organic matter) increased in the order of diets characterized by oat hulls (0.92), guar gum (0.99), wheat (1.04), soybean hulls (1.13), apple pulp (1.15), Jerusalem artichoke (1.21), sugar beet pulp (1.24), and molasses (1.37). According to multiple regression analysis, diets with high sugar content enhanced methane release while methane was low with high dietary lignin content. Regressions also showed that different fibrous carbohydrates had only a minor effect on methane release, probably due to lignification of the fiber. The present results suggest that equations for the estimation of methane emission of ruminants should consider dietary carbohydrate composition and lignin content. Key words: Methane, carbohydrates, lignin, Jerusalem artichoke, guar gum, ruminant
In situ rumen degradation kinetics of timothy and alfalfa as affected by cultivar and stage of maturity
Authors: Yu P. , Christensen D. A. , McKinnon J. J.
Published: April 2011

The objective of this study was to investigate the effects of cultivar and stage of maturity at cutting on rumen degradation characteristics of some feed components in alfalfa (Medicago sativa L.) and timothy (Phleum pratense L.). Two adapted cultivars of alfalfa (Pioneer and Beaver) and timothy (Climax and Joliette), grown in Saskatchewan (Canada), were cut at three stages: 1 = 1 wk before commercial cut (early bud for alfalfa; joint for timothy); 2 = at commercial cut (late bud for alfalfa; pre-bloom head for timothy); 3 = 1 wk after commercial cut (early bloom for alfalfa; full head for timothy). Rumen degradation characteristics, including rapidly degradable fraction (A), potentially degradable fraction (B), undegradable fraction (C), degradation rate (Kd), lag time (T0), and effective degradability (ED) of each component, were determined using in situ technique and analyzed by first order kinetic equation described by Ørskov and McDonald with lag time. The results showed that, in alfalfa, the cultivars have no effect on rumen degradation characteristics of dry matter (DM), organic matter (OM), crude protein (CP), and neutral detergent fiber (NDF) and acid detergent fiber (ADF). However, the stage of maturity at cutting has large effects on each component, except CP. Generally, with increasing stage of maturity, it decreased A or B and increased C without affecting Kd and T0, thus resulting in decreasing the ED fraction. In timothy, the cultivars have effects only on rumen degradation characteristics of CP. Climax has a higher effective degradability of CP (EDCP) than Joliette. The stage of maturity at cutting has a large impact on rumen degradation characteristics of each component. Increasing stage of maturity did not affect A, but reduced B and increased C without affecting Kd and T0, thus resulting in reducing ED fraction. In conclusion, Pioneer and Beaver alfalfa have similar rumen degradation characteristics for all feed components. Climax and Joliette timothy were different only on CP degradation pattern with Climax having a higher EDCP fraction than Joliette. The stage of maturity at cutting had a significant impact on rumen degradation characteristics for both forages. Generally, it decreased ED with increasing stage of maturity. Our results indicate that it is inappropriate to assume fixed degradation characteristics for a forage without considering factors such as stage of maturity at cutting. Key words: Chemical component, rumen degradation characteristics, forage, cultivar, maturity
Effect of monensin on meal frequency during sub-acute ruminal acidosis in dairy cows
Authors: Lunn D. E. , Mutsvangwa T. , Odongo N. E. , Duffield T. F. , Bagg R. , Dick P. , Vessie G. , McBride B. W.
Published: April 2011

Two experiments were conducted to determine the effects of monensin (Rumensin® controlled-release capsule; exp. 1 and Rumensin® Premix; exp. 2) on meal frequency during grain-induced sub-acute ruminal acidosis (SARA) in Holstein dairy cows. SARA was induced by restricting total mixed ration intake to 85% of ad libitum intake and replacing the remaining 15% with a grain pellet consisting of 50% wheat and 50% barley. In both experiments, meal frequency during SARA was lower (P < 0.05) than meal frequency during the adaptation and recovery periods. In exp. 2, monensin increased meal frequency during SARA (6.0 vs. 7.2, P = 0.04) and meal frequency during the recovery period (7.5 vs. 9.0, P = 0.004). These results suggest monensin premix may increase meal frequency in lactating dairy cows under conditions of SARA. Key words: dairy cows, monensin, ruminal acidosis, meal frequency
Strong relationships between mediators of the acute phase response and fatty liver in dairy cows
Authors: Ametaj B. N. , Bradford B. J. , Bobe G. , Nafikov R. A. , Lu Y. , Young J. W. , Beitz D. C.
Published: April 2011

The objective of this study was to investigate the relationship between activation of acute phase response and fatty liver in transition dairy cows. Fatty liver was induced in dairy cows by feeding 8 kg of cracked corn 1 mo before the expected day of parturition. Liver and blood samples were obtained at days -4, 3, 8, 12, 14, 22, 27, and 36 postpartum. Cows that developed fatty liver (n = 4) reached peak total lipids in the liver at day 12 postpartum with 11.4% (wet wt.) compared with 6.6% in control cows (n = 4). Cows with fatty liver had greater plasma tumor necrosis factor-alpha (TNF-α), nonesterified fatty acids (NEFA), and lower lactate concentrations than did control cows at day -4. During highest concentrations of total lipids in the liver, for at least one time-point, fatty-liver cows had greater concentrations of plasma serum amyloid A (SAA), haptoglobin, and NEFA and lower concentrations of calcitonin gene-related peptide (CGRP), prostaglandin E2 (PGE2), cortisol, and TNF-α than did control cows. Concentrations of total lipids in the liver at 12 d postpartum were correlated (a) positively with plasma TNF-α, SAA, and NEFA and negatively with plasma CGRP before calving, (b) positively with plasma SAA, haptoglobin, and NEFA and negatively with plasma PGE2, CGRP, total cholesterol, and glucose at days 3, 8, and 12 postpartum, and (c) negatively with concentrations of plasma glucose, lactate, and total bilirubin after day 12 postpartum. In conclusion, this study indicates that the acute phase response occurs in cows with fatty liver as well as strong relationships between mediators of immune response and fatty liver. Key words: Acute phase response, fatty liver, dairy cow
Nitrogen metabolism in beef steers fed gamagrass or orchardgrass hay with or without a supplement
Authors: Magee K. J. , Poore M. H. , Burns J. C. , Huntington G. B.
Published: April 2011

A 50:50 soybean hull:corn grain supplement fed at 0.75% of body weight (BW) decreased ad libitum gamagrass or orchardgrass hay intake by steers, but increased total dry matter (DM) intake, DM digestibility, N intake, and N retained. Supplementation had a greater effect on N metabolism in steers fed orchardgrass than steers fed gamagrass. Key words: Steers, beef, hulls, soybean, metabolism, nitrogen
Comparison of purines and nitrogen-15 as microbial flow markers in beef heifers fed barley- or corn-based diets
Authors: Hristov A. N. , McAllister T. A. , Ouellet D. R. , Broderick G. A.
Published: April 2011

The objective of this study was to estimate the contribution of microbial purine bases to duodenal purines and to purine derivatives [allantoin and uric acid (PD)] excreted in the urine. Additionally, microbial protein (MCP) flow estimated using duodenal flow of purine bases was compared to estimates using 15N as a microbial marker. Four beef heifers were fed two diets, barley silage/barley grain/soybean meal (diet B) or corn silage/corn grain/corn gluten meal (diet C), in a cross-over design study. (15NH4)2SO4 was infused in the rumen for 8 d to label ruminal microorganisms and their purine bases. Rumen contents, duodenal digesta, urine, and feces were sampled during the last 2 d of tracer infusion and for 48 h after the infusion ceased. The animals consumed more (P < 0.01) dry matter (DM), organic matter (OM), N, and neutral detergent fiber (NDF) with diet B than with diet C. Total tract digestibilities of DM, OM, and NDF were also higher (P < 0.01) with diet B. Ruminal ammonia (P < 0.01), volatile fatty acids (P < 0.05), and acetate (P < 0.01) concentrations and xylanase activity (P < 0.05) were higher with diet B compared with diet C. Flow of MCP to the duodenum was estimated from duodenal samples using purines or 15N as microbial markers, or from urinary PD excretion. The effects of diet or method of measurement on MCP flow were not significant. However, when the urinary PD method was excluded from the analysis, MCP flow was greater (by 26%; P = 0.01) when estimated using 15N vs. the purine-based method. The difference was mainly due to underestimation of the proportion of microbial N in the liquid duodenal digesta with the purine method. Feed purines contributed from 3.5 (liquid digesta phase) to 19.7% (solid digesta phase) of the total purine flow at the duodenum. 15N enrichment of urinary PD was 1.08 of the enrichment of duodenal purines, suggesting that feed purines contributed little N to urinary allantoin and uric acid in cattle. Key words: Allantoin, cattle, microbial protein synthesis, nitrogen-15, purine derivative
Effect of supplementing phytase to corn- or wheat-based gestation and lactation diets on nutrient digestibility and sow and litter performance
Authors: Nyachoti C. M. , Sands J. S. , Connor M. L. , Adeola O.
Published: April 2011

Effect of an Escherichia coli derived, 6-phytase on nutrient digestibility and sow and litter performance were investigated. Six (exp. 1) or eight (exp. 2) sows per diet were randomly assigned to a positive control (PC), a negative control (NC) with reduced non-phytate phosphorus (P), NC + 500 FTU kg-1, or NC + 1000 FTU kg-1 diet from day 60 of gestation to day 22 postpartum. Diets in exps. 1 and 2 were based on corn and wheat, respectively. Energy, N, calcium (Ca), and P digestibilities were determined between days 73 to 77 (Period 1), 104 to 106 (Period 2) of pregnancy, and days 16 to 20 postpartum. Sow and litter performance were monitored. During gestation, phytase at 500 FUT kg-1 did not affect nutrient digestibility in exp. 1 but improved (P < 0.05) DE and digestibilities of DM, energy, N, and P in exp. 2. Increasing phytase to 1000 FTU kg-1 reduced (P < 0.05) digestibilities of energy and N (exp. 1). In both experiments, digestibilities of N, Ca, and P were higher (P < 0.05) in period 2 than period 1. During lactation, supplementing the NC diet with 500 FTU kg-1 only improved (P < 0.05) DE and Ca and P digestibility in exp. 1 and DE and digestible P in exp. 2. Compared with NC, P digestibility and digestible P were higher (P < 0.05) in the NC + 1000 FTU kg-1 diet in both experiments. Sow and piglet performance was unaffected by diet in both experiments. In conclusion, P digestibility was greater between days 104 and 106 of gestation than between days 73 and 77 of gestation and phytase improved P digestibility during lactation but this effect was not consistent during gestation in both experiments. Key words: Digestibility, phytase, phosphorus, sows
Modeling nutrient supply to dairy cattle from a feedstuff using NRC-2001 (a TDN-based model) with inputs based on in situ and mobile bag technique measurements
Authors: Yu P.
Published: April 2011

The objectives of this study were to use the NRC-2001 model with inputs based on in situ and mobile bag techniques to (1) predict the potential nutrient supply to dairy cows using an exampled feed- whole lupin seeds that were systematically toasted and (2) quantitatively determine the effects of toasting (which shifted degradation of protein from the rumen to the abomasum and small intestine without changing intestinal digestion) and optimal toasting conditions by the NRC-2001 model. The quantitative predictions were made in terms of: (1) rumen undegraded and degraded feed protein, (2) truly absorbed undegraded protein, (3) potential microbial protein synthesized in the rumen from rumen available protein or (4) from total digestible nutrients (TDN), (5) truly absorbed rumen synthesized microbial protein, (6) truly absorbed rumen endogenous protein, (7) total metabolizable protein (MP), as well as (8) the protein degradation balance (PDB). The results show that using the NRC-2001 model with inputs based on in situ and mobile bag techniques, the predicted PDB and MP supply to dairy cattle was significantly improved. However, no optimal condition could be obtained from this study due to high PDB values (>48 g kg-1 DM) in all the treatments, predicted by the model. With toasting, temperature and/or duration could go still higher than 136°C and/or longer than 15 min to further prevent potential N loss in the rumen if total tract digestion is not depressed. More study is needed. However, the results differed from that published with the DVE/OEB system (a non-TDN-based model) although the two models had significant correlations with high R (>0.99) values. Using the NRC model, the overall mean for MP was higher (+10 g kg-1 DM), but the PDB values were lower (-12 g kg-1 DM) in comparison with that predicted by the non-TDN based model for the whole lupin seeds. Key words: Modeling nutrient supply, dairy cattle; National Research Council, in situ, mobile bag technique
Identification of single nucleotide polymorphisms in avian uncoupling protein gene and their association with growth and body composition traits in broilers
Authors: Zhao Jianguo , Li Hui , Kong Xiangtao , Tang Zhiquan
Published: April 2011

Uncoupling protein (UCP) genes are members of the mitochondrial membrane transporter family. They could increase energy expenditure via diminishing the resulting production of adenosine triphosphate (ATP) and instead yielding dissipative heat. Some studies showed that decrease of the energy expenditure was the main reason causing obesity. We identified two SNPs in avian UCP gene and genotyped them in broiler lines that underwent divergently selection for abdominal fat after six generations using the percentage of abdominal fat as well as very low-density lipoprotein (VLDL) as the selection criterion. Two polymorphisms were found in the 3' untranslated region (UTR) (A1197C) and intron 2 (C1240A) region. Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and PCR-Restriction Fragment Length Polymorphism (PCR-RFLP) methods were then developed to genotype the population. The correlation between the UCP SNPs and growth as well as body composition traits were carried out using mixed model analysis. Results showed that the polymorphism of A1197C had an effect on percentage of abdominal fat (AFP), abdominal fat weight (AFW) and liver weight (LW). The C1240A polymorphism had effects on body weight (BW), carcass weight (CW), LW and gizzard weight (GW). There is a significant association between the UCP genotypes and the growth and body composition traits in the broiler lines. Key words: Broiler, uncoupling protein gene, SNPs, growth, body composition
Effect of pharmacological intakes of zinc and copper on growth performance, circulating cytokines and gut microbiota of newly weaned piglets challenged with coliform lipopolysaccharides
Authors: Namkung H. , Gong J. , Yu H. , de Lange C. F. M.
Published: April 2011

The effect of feeding pharmacological levels of zinc (Zn) and copper (Cu) to newly weaned piglets on growth performance, circulating cytokines levels and gut microbiota was investigated. One hundred eighty piglets [5.90 ± 0.18 kg body weight (BW); six pigs per pen] weaned at 16 to 19 d of age were fed diets containing 3000 ppm additional Zn, 250 ppm additional Cu or a control diet (150 ppm Zn, 15 ppm Cu) for 14 d post-weaning (weeks 1 and 2). Pigs were fed a control diet for an additional 2 wk. Pigs were injected intramuscularly on days 13 and 19 with either 75 μg kg-1 BW of coliform lipopolysaccharide (LPS) or an equivalent amount of saline. Blood samples were collected 3 h after LPS injection to measure plasma levels of cytokines and cortisol. Digesta of ileum and colon were collected from non-challenged pigs on days 14 and 28 to evaluate microbiota using conventional culturing methods and polymerase chain reaction and denaturing gradient gel electrophoresis (PCRDGGE) analysis of the 16S rRNA genes. There were no interactive effects of diet and LPS challenge on growth performance (P > 0.10). Compared with the control, high dietary Zn and Cu increased (P < 0.01) average daily gain (ADG) during weeks 1 (0.125, 0.091 vs. 0.074 kg; P < 0.05) and 2 (0.240, 0.270 vs. 0.155 kg; P < 0.01) only. LPS injection reduced ADG during weeks 2 and 4 (P < 0.01). Dietary treatment did not affect feed efficiency (P > 0.10). Challenging pigs with LPS reduced (P < 0.01) feed efficiency during week 2, but increased (P < 0.05) feed efficiency during week 3. There were no interactive effects between diet and LPS on plasma cytokines levels, except for cortisol (P < 0.05). Plasma levels of cytokines (interleukin-1β, interferon-γ, tumour necrosis factor-α) and cortisol increased (P < 0.01) in pigs challenged with LPS. The high levels of dietary Zn and Cu reduced (P < 0.05) the increases in plasma cortisol level in LPS-challenged pigs at days 9 and 19. There were no differences among the dietary treatments in counts of coliforms and lactobacillus in the digesta from ileum and colon (P > 0.10). PCR-DGGE analysis showed that high levels of dietary Zn and particularly Cu significantly reduced the diversity of ileal microbiota. The effect on microbiota diversity was reversible when dietary Zn and Cu were removed. Enhanced growth performance of the newly weaned piglets fed high dietary Zn and Cu appears mediated via changes in gut microbiota as well as a reduced cortisol response following an immune challenge. Key words: Piglets, zinc, copper, lipopolysaccharide, gut microbiota, cytokines
Effect of feeding different sources of fat during gestation and lactation on reproduction of beef cows and calf performance
Authors: Petit H. V. , Berthiaume R.
Published: April 2011

Experiment 1: Over a 2-yr period, a total of 231 Angus crossbred cows were assigned randomly to one of three gestation diets to evaluate the effects of fat sources on birth weight, weaning weight and average daily gain of calves, calf condition at birth, calf mortality, body weight of cows, gestation length, calving percentage, and the percentages of retained placenta and dystocia. Isonitrogenous and isoenergetic supplements were based on whole flaxseed (FLA), calcium salts of palm oil (Megalac®, MEG) or no fat (CON). All cows were fed grass silage (90% of ad libitum intake) until 1 mo before calving. Cows were then fed grass silage for ad libitum intake until they were put on pasture. Cows were offered 600 g of supplement per head per day starting 43 d before the first calving for a period averaging 78 d. Diet had no effect on body weight (BW) of cows at calving. Birth weights of calves were similar among treatments. However, calf mortality percentage at birth was almost four times higher (P = 0.03) for cows fed CON compared with those fed FLA and MEG. More than 90% of cows rejected placenta within 12 h of calving and treatment had no effect. Cows fed FLA and CON tended (P ≤ 0.10) to have higher cumulative pregnancy rates (92.9 and 91.9%, respectively) than those fed MEG (76.7%). Experiment 2: From 2000 Jan. 19 to 2000 Sep. 05, 41 heifers received 600 g per head per day of one of the three supplements used in exp. 1 to determine the effect of fat supplementation during pregnancy and breeding. Diet had no effect on calf birth weight, but contrasts indicated that heifers fed MEG tended (P = 0.09) to have a lower pregnancy rate than those fed CON. These data suggest that cows and heifers fed grass silage and/or on pasture would not be deficient in omega 3 fatty acids, thus would not benefit from a supplement rich in omega 3 fatty acids such as flaxseed. However, fat supplementation contributed to lower calf mortality at birth in cows, but not in heifers. Key words: Beef, flaxseed, reproduction, fatty acids
Effect of maceration of bromegrass-alfalfa silage on ruminal degradability and performance of lactating dairy cows
Authors: Ouellet D. R. , Lapierre H. , Chiquette J.
Published: April 2011

Maceration of bromegrass-alfalfa sward increased effective ruminal degradability of dry matter, neutral detergent fibre, and gross energy, but decreased the degradability of protein. Despite improvement in ruminal degradation kinetics, inclusion of the macerated silage (43% of total mixed ration dry matter) between weeks 7 and 15 of lactation had limited effect on lactational performance. Key words: Forage, silage, maceration, rumen degradability, lactation
Thermal denaturation of bovine longissimus thoracis aponeurosis, correlating contraction with optical changes
Authors: Swatland H. J.
Published: April 2011

Beef rib roasts and steaks have a thick connective tissue aponeurosis which is often difficult to gelatinise by cooking. When heated in a water-bath, aponeurosis first increased in reflectance (maximum 0.026 ± 0.021 at 67.1 ± 5.5°C) before decreasing in reflectance as gelatinisation occurred. Contraction reached a maximum of 33.8 ± 15.8% of starting length at 69.2 ± 3.2°C and corresponded to the increase not the decrease in reflectance. Either contraction or increased reflectance might be used to select animals with low-temperature gelatinisation. Key words: Beef toughness, aponeurosis, cooking
Elimination of residual molybdenum in cattle exposed to high molybdenum forage
Authors: Steinke D. R. , Majak W. , McGillivray J. , Lysyk T. J.
Published: April 2011

The elimination of molybdenum (Mo) from tissues of cows grazing extremely high Mo forage (> 100 ppm Mo dry weight) at the Highland Valley Copper mine in British Columbia, Canada, was measured to determine when these animals could be accepted for slaughter to produce meat suitable for human consumption. Molybdenum levels in muscle and fat were 10-fold lower than those in liver tissue. The results demonstrated that muscle and fat tissues would be acceptable for human consumption after 1 mo, but a clearance period of 3 mo prior to slaughter would be required before the liver could be introduced into the food chain. Key words: Tissue molybdenum and elimination, cattle grazing