bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of wheat cultivar, growing environment, and enzyme supplementation on digestibility of amino acids by broilers
Authors: Bedford M. R. , Scott T. A. , Silversides F. G. , Classen H. L. , Swift M. L. , Pack M.
Published: March 2010

Fifty-four samples of wheat, representing duplicate samples of nine varieties grown in three environments, were included in chick bioassays using rapidly growing broilers, complete diets, and enzyme supplementation to remove the deleterious effects of non-starch polysaccharides. An insoluble ash marker was included in the diets, which allowed calculation of apparent digestibilities of CP and AA in the grain from analysis of the ileal contents obtained after sacrifice of the chicks at 17 d of age. The wheat cultivars contained from 13.5 to 16.8% CP and differed in the percentage of specific AA, with Pro, Glu and Phe making up proportionately larger parts of high CP samples than low CP samples. Without enzyme supplementation, the digestibility of CP varied from 83 to 88% and that of specific AA from 76 to 94%, determined in part by the class and variety of wheat. Xylanase enzyme supplementation improved the digestibility of protein by an average of 4%, and reduced the differences in digestibility between wheat samples. These results suggest that variation between wheat samples should be taken into consideration when formulating broiler feed, especially when formulation is for specific AA. Enzyme supplementation may provide a partial alternative to using high-quality protein sources or supplementing with synthetic AA. Key words: Broiler chicken, digestible amino acids, digestible protein, wheat, enzyme
Origin of the preovulatory follicle after induced luteolysis during the early luteal phase in ewes
Authors: Viñoles Carolina , Rubianes Edgardo
Published: March 2010

The origin of the preovulatory follicle (POF) was determined by daily transrectal ultra-sonographic examinations in ewes given PGF2α on day 5 (n = 8) or day 9 (n = 8) post-ovulation. In all day-9 ewes, the POF originated from wave 2 while in the day-5 group it originated from wave 1 (n = 5) or wave 2 (n = 3). When the POF originated from wave 2 in day-5 ewes, the dominant follicle of wave 1 emerged earlier than in ewes with the POF from wave 1 (day –1.0 vs. day 0.8, P < 0.05) and was regressing at the time of PGF2α treatment (diameter 4.1 ± 0.4 vs. 2.8 ± 0.3 mm, P < 0.05). The dominant follicle of wave 1 became POF if it was in the growing or plateau phase at the time of luteolysis. If it was already in the regressing phase, the dominant follicle of wave 2 became the POF. Key words: PGF2α, luteolysis, ovarian follicular waves, ultrasonography, ewes
Changes in serum concentrations of folates, pyridoxal, pyridoxal-5-phosphate and vitamin B12 during lactation of dairy cows fed dietary supplements of folic acid
Authors: Girard C. L. , Matte J. J.
Published: March 2010

The present experiment was undertaken to determine the effects of dietary supplements of folic acid (FA) administered from 4 wk prepartum to 305 d of lactation on serum concentrations of folates, vitamin B12, pyridoxal-5-phosphate (P-5-P) and pyridoxal. In addition, concentrations of blood hemoglobin and packed cell volume (PCV) were determined. Sixty-three Holstein cows were assigned to 22 incomplete blocks according to lactation number, milk production and body weight (BW). Within each block, cows received 0, 2 and 4 mg FA d−1 kg−1 BW. Dietary supplements of FA increased serum concentrations of folates (time × FA, P = 0.0001); the highest concentrations were observed during the first two months of lactation in cows fed supplementary FA. The lowest serum concentrations of vitamin B12 were also observed during the first two months of lactation, and the concentrations were lower in primiparous than in multiparous cows (time × parity, P = 0.03). Serum concentrations of P-5-P and pyridoxal were not affected by the dietary supplements of FA (P > 0.1). In multiparous cows, dietary supplements of FA had no effect on changes of hemoglobin and PCV during the lactation (time × FA, P > 0.13). In primiparous cows, PCV and hemoglobin were lower in control cows at parturition whereas by 24 wk of lactation, they were higher in cows fed the highest amount of FA. The lowest values of hemoglobin and PCV were observed during the first two months of lactation. These results give an indication that supply of B-complex vitamins by ruminal microorganisms could be suboptimal for high-producing dairy cows, for example, in early lactation when fed a diet with a high proportion of concentrates. More research is needed to determine the metabolic consequences of these variations. Key words: Dairy cow, vitamin B6, vitamin B12, folic acid, lactation
Effects of photostimulatory lighting and feed allocation in female broiler breeders 1. Reproductive development
Authors: Robinson F. E. , Renema R. A. , Bouvier L. , Feddes J. J. R. , Wilson J. L. , Newcombe M. , McKay R. I.
Published: March 2010

Changes in carcass traits during sexual maturation were studied with female Shaver Starbro breeders in a 2 × 2 factorial design with two lighting programs and two feeding programs. Pullets were individually caged in a light tight facility at 20 wk of age. The light period of fast photoperiod (FP) hens was changed from 8L:16D to 15L:9D at 20 wk of age. Slow photoperiod (SP) hens were switched from a 8L:16D photoperiod at 20 wk to 11L:13D, with increases to 12L:12D, 13L:11D, 14L:10D, and 15L:9D weekly to 24 wk of age. Slow feed (SF) hens were given small (5 g or less) weekly increases in feed allocation from 20 to 25 wk. Fast feed (FF) hens received larger feed allocations than the SF birds from 20 to 25 wk (maximum difference of 25 g more feed than SF hens received). Birds were processed at weekly intervals between 20 and 26 wk of age (Group A) or at sexual maturity (Group B), which was considered to be the day of the first oviposition.Age at sexual maturity did not differ due to photostimulation or feeding treatment. Whereas feeding program had no effect on carcass composition parameters at sexual maturity, the SP hens had a higher relative carcass lipid content at the expense of protein and ash content compared to FP hens. The weight of the large yellow ovarian follicles (LYF) at sexual maturity was affected by feeding regimen (FF, 50.2 g; SF, 43.6 g) and photoperiod (FP, 43.2 g; SP, 50.6 g). While hens on the SP photostimulation program had 8.9 LYF compared to 8.0 in FP hens at sexual maturity, the FF feeding regimen hens had 9.0 LYF compared to 7.9 in SF hens. The gradual feeding program of the SF treatment may be a potential means of limiting follicle recruitment and thereby potentially increasing settable egg production compared with feeding programs using more rapidly increasing feed allocations. Key words: Broiler breeders, photostimulation program, feed restriction, ovary morphology
Effects of photostimulatory lighting and feed allocation in female broiler breeders 2. Egg and chick production on characteristics
Authors: Robinson F. E. , Renema R. A. , Bouvier L. , Feddes J. J. R. , Zuidhof M. J. , Wilson J. L. , Newcombe M. , McKay R. I.
Published: March 2010

Changes in egg production, chick production, and egg laying patterns were examined in individually caged female Shaver Starbro breeders in a 2 × 2 factorial design based on two photostimulation programs and two feeding programs. The light period of Fast Photoperiod (FP) hens was changed from 8L:16D to 15L:9D at 20 wk of age. Slow Photoperiod (SP) hens were switched from a 8L:16D photoperiod at 20 wk to 11L:13D, with increases to 12L:12D, 13L:11D, 14L:10D, and 15L:9D weekly to 24 wk of age. Slow Feed (SF) hens were provided small (5 g or less) weekly increases in feed allocation from 20 to 25 wk. Fast Feed (FF) hens received larger feed allocations from 20 to 25 wk (maximum difference of 25 g more feed than SF hens received). Individual body weight, egg production, sequence length profiles, fertility, and hatchability were monitored to 64 wk of age.Whereas all treatments had a high rate of egg production, total egg production was 10.9 eggs greater in the SF feeding program (200.3) compared to the FF program (189.4). Hen-day production of SF birds was 68.2% for the laying period compared to 64.5% for FF birds over the 42 wk laying period. The mean laying sequence length of SF birds was 36.4% longer than for FF birds, indicating superior egg laying patterns and ability to maintain egg production. Sequence length was longer in FP than in SP hens in early lay (22 to 35 wk of age), although this effect appeared to be transient. Hatch of fertile and hatchability were increased in the SP compared to the FP birds, indicating an advantage to the SP program with regard to total number of chicks produced. Examination of embryonic mortality by 7-d periods of incubation indicated that the FF birds had a higher incidence of early and mid-term embryonic mortality than the SF birds, possibly relating to developmental problems associated with eggs of birds with excessive follicle development. These data demonstrate that minor differences in feed allocation can have an influence on egg and chick production traits and that precise early breeder hen management is paramount to optimize chick output. Exposing 20-wk old pullets to small, multiple feed increases can increase egg production. Key words: Broiler breeders, photostimulation program, feed restriction, egg production, fertility
Digestibility by mink and storage stability of feedstuffs made from raw ground, acid-treated or fermented dogfish (Squalus acanthias)
Authors: White M. B. , Anderson D. M. , Rouvinen K. I.
Published: March 2010

Dogfish was evaluated in a 3 × 4 factorial design experiment conducted to determine digestibility coefficients (DC) of dry matter (DM), crude protein (CP), crude fat (CF), gross energy (GE) and amino acids (AA) in raw ground dogfish (RGD), acid (ASD) and fermented (FSD) dogfish silages for mink. The ASD was prepared with the addition of 2.5% (wt:wt) formic acid (conc. 85%) and 200 mg kg−1 antioxidant (ethoxyquin) to the raw ground fish. The FSD was produced with the addition of the commercial biopreservative Marisil®, (Finn Sugar) (1%) and extruded wheat (15%) to the raw ground fish. In the digestibility trial, consisting of three, 11-d periods, each having a 6-d adjustment followed by a 5-d collection, 12 mature standard type mink were confined to metabolism cages. Using the total collection (TC) method, where graded levels (0, 15, 30 and 45%) of the test feedstuff were substituted into a basal diet, an extrapolation using regression analysis was done to estimate digestibility of each test feedstuff. The AD of DM, CP, CF and GE was RGD: 81.8, 92.2, 96.2 and 89.6%; ASD: 87.1, 92.6, 100.0 and 93.2%; FSD: 86.0, 93.3, 98.1 and 90.4%, respectively. The AD of AAs was generally highest in the fermented dogfish feedstuff. A quality evaluation of the silages was conducted in a completely randomized design with four replications (two replications for AAs), to determine storage stability of the silages, on 10 different sampling days (days 1, 3, 6, 9, 15, 30, 90, 180, 270 and 360), (three sampling days for AAs) post-manufacture. The ASD was stable up to 180 d, after this storage time it underwent increases in pH and total volatile nitrogen (TVN) and decreases in N and AA content. The preservation of dogfish with a fermentation method (FSD) was judged to be unsuccessful with this feedstuff having a high initial pH (6.4) and large increases in TVN content early in storage. It was concluded that feedstuffs made from dogfish would provide a source of highly digestible nutrients for mink; however, more research is required before a fermented dogfish feedstuff can be incorporated into practical mink diets. Key words: Apparent digestibility, dogfish, fish by-products, mink, silage, silage quality
Dietary acorns provide a source of gamma-tocopherol to pigs raised extensively
Authors: Rey A.I. , Isabel B. , Cava R. , Lopez-Bote C. J.
Published: March 2010

Pigs raised extensively and fed acorns and grass had a higher concentration of alpha and gamma-tocopherol in longissimus dorsi muscle and microsome extracts than pigs fed in confinement with mixed diets (P < 0.001). This is attributable to the high concentration of alpha-tocopherol in grass (over 200 mg kg−1 DM) and gamma-toco-pherol in acorns (60–70 mg kg−1 DM). Key words: Pig, acorn, gamma-tocopherol, diet
The nutritive value of hemp meal for ruminants
Authors: Mustafa A. F. , McKinnon J. J. , Christensen D. A.
Published: March 2010

Hemp meal (HM) is derived from the processing of hemp (Cannabis Sativa L.) seeds. The objective of this study was to determine the nutritive value of HM for ruminants. Two ruminally fistulated cows were used in a randomized complete-block design to estimate in situ ruminal dry matter (DM) and crude protein (CP) degradability of HM relative to canola meal (CM), heated canola meal (HCM) and borage meal (BM) meal. Intestinal availability of rumen undegraded CP was estimated using a pepsin–pancreatin in vitro assay. Twenty growing lambs were utilized in a completely randomized design to determine total–tract nutrient digestibility coefficients of diets in which HM replaced CM at 0, 25, 50, 75 and 100% as a protein source. Results of the in situ study showed that the soluble-CP fraction of HM was similar to that of HCM and lower (P < 0.05) than those of CM and BM. Rate of degradation of the potentially degradable CP fraction and effective CP degradability of HM was higher (P < 0.05) than HCM and lower (P < 0.05) than CM and BM. Rumen undegraded CP and intestinal digestibility of RUP were highest (P < 0.05) for HM and HCM (average 782.5 and 644.5 g kg–1 of CP, respectively), intermediate for CM (473.9 and 342.9 g kg–1 of CP, respectively) and lowest for BM (401.5 and 242.3 g kg−1 of CP, respectively). However, total available CP was similar for the four protein sources (average 857.8 g kg−1 of CP). Feeding up to 200 g kg−1 HM did not affect voluntary intake or total-tract nutrient digestibility coefficients for sheep fed a barley-based diets. Hemp meal is an excellent source of RUP, with high post-ruminal availability, and may be used to replace CM with no detrimental effects on nutrient utilization by sheep. Key words: Hemp meal, nutritive value, ruminants
A comparison of two estrus synchronization methods in beef heifers
Authors: Stephens L. A. , Rajamahendran R.
Published: March 2010

This study compared the use of two injections of prostaglandin F2α(PGF2α) given 11 d apart with the use of gonadotropin releasing hormone (GnRH) followed by PGF2α after 7 d for synchronizing estrus in beef heifers. Heifers synchronized with GnRH and PGF2α showed weak signs of estrus and were more difficult to inseminate. There were no significant differences in synchronization rate and pregnancy rate. Key words: Estrus synchronization, beef heifers, gonadotropin releasing hormone, prostaglandin F2α
Effect of cultivar and environment on the feeding value of Western Canadian wheat and barley samples with and without enzyme supplementation
Authors: Scott T. A. , Silversides F. G. , Classen H. L. , Swift M. L. , Bedford M. R.
Published: March 2010

The feeding value ofnine wheat cultivars grown in replicate in three locations in each of two crop years, and 14 barley cultivars grown in seven locations over three crop years was tested with or without an appropriate commercial enzyme using a broiler chick bioassay. Four pens of six male broilers were fed mash diets containing 80% of the test cereal with or without enzyme from 4 to 17 d. Digestibilities were determined using an acid insoluble ash marker at 1.1% of diet. Significant intraclass correlation coefficients between duplicate wheat samples suggested a common effect of the location, but their low to moderate values suggested the presence of random variation or variation due to unique growing conditions within location. For both wheat and barley samples, the growing location affected the feeding value of the cereal grain and subsequent broiler chick performance. Durum wheat cultivars had higher feeding values than that of other wheat classes, both with and without enzyme supplementation, and the response to enzyme supplementation was low, likely reflecting a low level of soluble non-starch polysaccharides. The values of hulless barley cultivars were similar to those of hulled cultivars without enzyme, but the lower crude fibre in hulless barley resulted in higher feeding values when diets were supplemented with enzyme. The response to enzyme supplementation for both wheat and barley cultivars was dependent on the feeding value of the cereal grain without supplementation. Knowledge of variation in enzyme response could be used by feed manufacturers to determine the economic merit of supplementing with enzymes. Key words: Metabolizable energy, broilers, performance, wheat, barley, enzyme
An ω-3 fatty acid enriched chia diet: Influence on egg fatty acid composition, cholesterol and oil content
Authors: Ayerza(h) R. , Coates W.
Published: March 2010

Twenty-four Issa Brown laying hens were fed for 4 wk for the purpose of comparing a control diet with a diet containing 30% whole chia (Salvia hispanica L.) seeds. Egg weight and production, cholesterol content, total fat content, and fatty acid composition of the yolks were determined weekly. Sensory evaluation was conducted on eggs from the final week of the trial. Egg production was significantly (P < 0.05) greater for the control, although individual egg weights were not significantly different. No statistically significant difference (P < 0.05) in yolk fat content was found between treatments. Saturated palmitic fatty acid content of yolks was significantly (P < 0.05) less with the chia diet, with a 35% difference found at the end of the trial. Polyunsaturated, ω-3 α-linolenic fatty acid was significantly greater (P < 0.05) in yolks from the chia diet, and increased from 0 to 14.7% by the end of the trial. Chia improved the saturated:polyunsaturated fatty acid ratio in the yolks, compared to the control diet. No significant differences (P < 0.05) in taste preferences or off-flavors were found between eggs from both treatments. Key words: Egg yolk, chia, ω-3 α-linolenic fatty acid, cholesterol, flavor
Contributions of preweaning growth information and maternal effects for prediction of carcass trait breeding values among crossbred beef cattle
Authors: Crews Jr. D. H. , Kemp R. A.
Published: March 2010

Preweaning and carcass trait records from crossbred steers (n = 1015) and heifers (n = 957) were used to estimate genetic parameters and to investigate the efficacy of maternal effects and preweaning growth information for improving estimation of EBV for carcass traits for crossbred beef cattle. Dams (n = 775) representing three F1 and twelve back-cross combinations involving the Charolais, Hereford, Angus, Simmental and Shorthorn breeds were mated over six years to Limousin bulls (n = 36) at two locations in western Canada. Four animal models, involving from zero to three maternal (co)variances were used to analyze four carcass traits. Rank and simple correlations indicated that maternal effects were relatively unimportant for estimation of direct carcass trait breeding values. Direct heritabilities were 0.28, 0.12 and 0.16 for birth weight, preweaning daily gain and weaning weight, and were 0.20, 0.35, 0.50 and 0.38 for hot carcass weight, fat thickness, ribeye area and percent lean yield, respectively. Maternal heritabilities were 0.21, 0.22 and 0.40 for birth weight, preweaning daily gain and weaning weight, respectively. Estimated genetic correlations between percent lean yield and hot carcass weight, fat thickness and ribeye area were –0.05, –0.85 and 0.39, respectively, and 0.30 between hot carcass weight and ribeye area. Direct genetic effects for birth weight had moderate (0.51 to 0.54) correlations with direct effects for carcass weight, ribeye area and percent lean yield. Direct genetic effects for fat thickness were negatively correlated with direct effects for birth weight (−0.44), preweaning daily gain (−0.15) and weaning weight (−0.25). Maternal genetic effects for preweaning traits had near-zero correlations with direct genetic effects for fat thickness and percent lean yield. Adding preweaning growth information to genetic evaluations for carcass traits slightly decreased prediction error variances for breeding values and would be recommended when information on carcass traits is limited. Key words: Genetic evaluation, carcass traits, beef cattle
Effect of diet, digesta processing, freezing and extraction procedure on some polysaccharide-degrading activities of ruminal contents
Authors: Hristov A. N. , McAllister T. A. , Cheng K.-J.
Published: March 2010

Three procedures for extracting polysaccharide-degrading enzymes (PDE) from ruminal contents were compared, and the effects of diet, inoculum preparation and freezing of samples on recovery of enzyme activities were evaluated. Four nonlactating cows and four heifers were fed either high-forage (83%, dry matter [DM] basis) or high-grain (91%, DM basis) diets. Three sample types, (1) enriched ruminal fluid; (2) blended enriched ruminal fluid; and (3) whole ruminal content, were analyzed fresh or after having been frozen (−40 °C) for 48 h. Four cell-free preparations of each sample type were assayed: (1) control (no enzyme extraction); and enzymes extracted by (2) sonication; (3) lysozyme; and (4) lysozyme + EDTA. Animals fed a high-grain diet had lower carboxymethylcellulase andxylanase but higher amylase activities in the rumen. Blending ruminal solids with buffer and combining the filtrate with cheese-cloth-filtered ruminal fluid produced higher polysaccharide-degrading activities per unit of DM compared with whole ruminal contents. In lysozyme treatments, freezing inactivated from 22 (amylase) to 52% (xylanase) of the enzyme activities measured in fresh ruminal fluid. Lysozyme treatment resulted in the highest enzyme recovery (from fresh ruminal fluid) of the extraction methods tested. With frozen samples, sonication and lysozyme gave similar results. If a large number of ruminal content samples are to be processed for PDE activities, freezing and subsequent sonication appear to be a practical alternative to extraction by lysozyme. Key words: Rumen, polysaccharide-degrading enzymes, extraction methods
Preferences of farmed silver foxes (Vulpes vulpes) for four different floor types
Authors: Harri M. , Mononen J. , Sepponen J.
Published: March 2010

Farmed silver foxes were allowed to choose between four standard farm cages, each of which was equipped with a different floor material: plastic-coated wire mesh (WM); dry wood (DW); dry sand (DS); and wet wood (WW) or icy sand (IS). Six males and six females were placed in the test environment singly in winter; and the same individuals, again in spring. The use of the different floors was videorecorded and analysed from the tapes for active periods and resting period on 5 or 6 d. Resting consisted of 14–20 separate bouts d−1, occupying 58–62% of the total 24 h. In winter, the active periods of the animal’s day were spent as follows: DW (34%) = DS (33%) > IS (17%) = WM (15%). The resting periods were spent as follows: DW (59%) > WM (26%) = DS (15%) > IS (1%). In spring, the order of active time was DS (36%) > DW (25%) = WW (24%) > WM (15%) and of resting time was DW (51%) > WM (19%) = WW (16%) = DS (15%). Different individuals preferred different floors, leading to large variance in the group means. This high variation may suggest a low level of priority in general but a high level of priority within individuals. Although solid floors were highly preferred when dry, they were least preferred when wet or icy. Key words: Preference test, wire-mesh floor, solid floor, wet floor, resting place, Vulpes vulpes
Dose-response of injected recombinant porcine prolactin on concentrations of prolactin in lactating sows
Authors: Horth S. , Laforest J.-P. , Farmer C.
Published: March 2010

HBlood profiles of prolactin (PRL) were obtained in sows after receiving a s.c. injection of 0 mg (n = 7), 5 mg (n = 10), or 15 mg (n = 9) of recombinant porcine prolactin (pPRL) on days 6 and 20 of lactation. The 15-mg dose of pPRL increased PRL concentrations (P ≤ 0.01) from 15 min to 11 h post-injection at both 6 and 20 d of lactation, whereas a sustained increase in PRL (P ≤ 0.05) following the 5-mg dose was seen on day 20 only, and lasted from 1 to 7 h post-injection. The results demonstrate that stage of lactation, as well as dose and time since PRL injection affect the PRL response of lactating sows to exogenous pPRL. Key words: Sow, lactation, prolactin, injection
Cellular and Molecular Biology: A new section for Canadian Journal of Animal Science
Authors: Schaefer A. L. , Dodson M. V.
Published: March 2010

As we approach the 21st century, it is appropriate to re-evaluate the sectional coverage of this scientific journal. Having done this over the course of the past 10 to 11 months, and having observed all proprieties of the Canadian Society of Animal Science, we hereby disclose that a new section is being added to the Canadian Journal of Animal Science. This new section is named: "Cellular and Molecular Biology". Dr. Michael V. Dodson of Washington State University (USA) is the section's first Associate Editor. Members of the Society and participants of the worldwide scientific community are welcome to submit scientific articles for inclusion in this section through the normal channels outlined in the journal's instructions to authors. Because this is the inaugural issue for the new section, papers from six different laboratories are included, covering the topics: cellular and molecular aspects of leptin, cellular and molecular biology of muscle growth and development, oocyte development, genetic markers, and molecular biology of the calpain system. As time passes we will encourage other laboratories to write papers, especially if initial submittals are slow, but we expect that a majority of future papers will be non-solicited "data" papers. As always, authority for style, scope and content resides with the Journals Policy Subcommittee and ultimately with the membership of the Canadian Society of Animal Science. Consequently, should there be any constructive criticism by Society membership about the new section as it has been founded, we will consider fine-tuning the section. Key words: Cellular and molecular biology
Productivity and sustainability of four grazed grass – alfalfa mixtures
Authors: Holt N. W. , Jefferson P. G.
Published: March 2010

Forage grasses need to be evaluated in pasture trials in the Great Plains region of North America. The objective of this study was to compare four grass–alfalfa (Medicago sativa L.) mixtures for productivity and persistence when grazed during spring and summer. The grasses were Altai wildrye (Leymus angustus [Trin.] Pilger), intermediate wheatgrass (Elytrigia intermedia [Host] Nevski), meadow bromegrass (Bromus riparius Rehm. syn. B. biebersteinii Roem. & Schult.) and Russian wildrye (Psathyrostachys junceus [Fisch.] Nevski), with grass rows seeded perpendicular to the alfalfa rows. Two sites, 4 km apart, were grazed with yearling beef cattle from 1987 to 1993. Forage yield differed among grass treatments in 4 of 5 years, but differences were inconsistent over time. Five-year mean forage yields and total livestock production were not significantly different among the four grasses. Mean annual forage yields ranged from 800 to 8170 kg ha−1 and were related to the amount of growing season (April–August) precipitation. Carrying capacity ranged from 35 steer grazing days per hectare in 1992 to 176 in 1991. Grasses in the mixtures did have a significant effect on the grass–alfalfa ratio and on ground cover. Alfalfa content was highest when grown with Altai wildrye and lowest when grown with Russian wildrye. Percentage of ground cover by the grass plus alfalfa increased from an average of 3.8% in 1987 to 16.1% at one site and 31.9% at the second site by 1993. Russian wildrye contained the least alfalfa and weeds after 7 yr. Intermediate wheatgrass and Altai wildrye did not compete with invading weeds at one site, or with alfalfa at the other, and should not be recommended for spring–summer pastures in semiarid regions. Meadow bromegrass maintained a balance of grass and alfalfa and further research should confirm its persistence in semiarid climates. Key words: Leymus angustus, Elytrigia intermedia, Bromus riparius, Psathyrostachys junceus, Medicago sativa, grazing with cattle
Effects of grazing dates on forage and beef production of mixed prairie rangeland
Authors: Schellenberg M. P. , Holt N.W. , Waddington J.
Published: March 2010

Conventional belief is that mixed prairie range is harmed by early spring use but not by moderate grazing after the grasses have flowered. Our hypothesis was that mixed prairie range may be grazed for a limited period in the growing season providing rest is allowed for the remainder of the year. This 6-yr test was established on a rolling site of range pasture, which contained, by area, 65% upland mixed prairie, 5% lowland bluegrass (Poa spp.) and 30% crested wheatgrass (Agropyron cristatum). The species mix is commonly found in southern Canadian prairies. The mixed prairie grasses were needle and thread (Stipa comata), northern wheatgrass (Elymus lanceolatus), western wheatgrass (Pascopyrum smithii) and blue grama (Bouteloua gracilis). Each pasture was 1.6 ha and was grazed with yearling beef cattle once a year beginning mid-May; the end of June; mid-August or late September. Forage yields in grazing-exclusion cages averaged 580, 2960, and 1370 kg ha−1 for the mixed prairie, lowland grasses, and crested wheatgrass, respectively. The date of grazing in the previous year did not affect current-year maximum forage yield. The main determinant of maximum forage yield was a combination of spring soil moisture plus April to June precipitation. Available forage for grazing, on average, doubled from mid-May until the end of June for the three forage types. There were year-by-grazing date interactions, which were related to distribution of precipitation. Mixed prairie was the preferred forage at the last two grazing dates. Forage digestibility, N and P content were highest during the May and June grazing period and declined thereafter. Average daily gain of the steers decreased from 0.9 kg d−1 in May and late June to 0.2 kg d−1 by late September. Annual carrying capacity (in standard animal units) was 40 d ha−1 in May and averaged 55 d ha−1 for the other dates, which were not different. Grazing mixed prairie did not have a negative effect on the yield of native grasses when used for only one short period per year. Delayed use from mid May to end of June increased available forage and carrying capacity. Key words: Mixed grass prairie, crested wheatgrass, grazing, weather effects
The effects of feeding conjugated linoleic acid on subsequent pork quality
Authors: Dugan M. E. R. , Aalhus J. L. , Jeremiah L. E. , Kramer J. K. G. , Schaefer A. L.
Published: March 2010

Feeding conjugated linoleic acid (CLA) has recently been shown to repartition fat to lean in pigs. The present study was undertaken to determine if feeding CLA affects pork quality. Pigs were fed a cereal-based diet containing either 2% CLA or 2% sunflower oil. Fifty-four pigs (27 gilts and 27 barrows) were fed per diet, and diets were fed from 61.5 to 106 kg liveweight. Diet did not affect postmortem longissimus thoracis (LT) glycogen utilization, lactate accumulation, or pH decline. Conjugated linoleic acid fed pigs had slightly higher LT temperatures at 3 h postmortem (+1.15 °C; P < 0.05), but subsequent LT shear force, drip loss and soluble protein levels were unaffected. Diet did not affect subjective LT scores for structure or color, but objective color measurements indicated LT from CLA-fed pigs had slightly higher chroma (color saturation) values (+0.84; P < 0.05). Longissimus thoracis from CLA-fed pigs also had increased subjective marbling scores (P < 0.01) and increased petroleum-ether-extractable intramuscular fat (+22%; P < 0.01). Diet did not affect any measured palatability characteristic (initial and overall tenderness, juiciness, flavor desirability, flavor intensity, connective tissue amount, overall palatability; P > 0.05). Feeding 2% dietary CLA to pigs, therefore, shows some potential for improving pork composition by increasing intramuscular fat, while having no detrimental effect on pork quality. Key words: Swine, conjugated linoleic acid, pork quality
Effect of feed particle size and dietary melatonin supplementation on gastric ulcers in swine
Authors: Ayles H. L. , Friendship R. M. , Bubenik G. A. , Ball R. O.
Published: March 2010

Gastric ulcers may be an underrecognized problem in the swine industry. An experiment was conducted to evaluate the effects of dietary melatonin supplementation and particle size on prevalence and severity of ulcers in growing pigs. Sixty-four Yorkshire barrows and gilts (29.5 ± 1.0 kg) received either a finely ground (763 ± 2.18 µm) or a coarsely ground (953 ± 2.29 µm) corn–wheat diet, either with or without added melatonin (5 mg kg−1). One half of the pigs underwent endoscopic examination to assess the severity of ulcers on days 4 and 25. Growth performance and feed consumption were monitored throughout the experiment. All pigs were slaughtered on day 28, and ulcers were assessed postmortem. Endoscopy at the beginning of the experiment found that 53% of the pigs already had some degree of ulceration. Pigs fed the fine diet had greater average daily gain and average daily feed intake than pigs fed the coarse diet (P < 0.05), but particle size did not significantly affect prevalence of stomach ulcers. Melatonin supplementation increased the apparent digestibility of crude protein (P < 0.04) and dry matter (P < 0.08) of the diets and decreased the prevalence of ulcers (P < 0.05) but did not significantly affect growth performance. Pigs that received melatonin had higher levels of melatonin (P < 0.01) in most gastrointestinal tissues, with highest concentrations found in the stomach (P < 0.001). Pigs that did not have ulcers had a higher concentration of melatonin in the plasma and stomach than pigs with ulcers (P < 0.05). Melatonin may be useful in decreasing ulcers. Initial ulcer condition may be a significant source of variation in growth experiments. Key words: Pigs, gastric ulcers, particle size, melatonin, gastrointestinal tract
Backfat thickness in pigs is positively associated with leptin mRNA levels
Authors: Robert Claude , Palin Marie-France , Coulombe Nathalie , Roberge Claude , Silversides Frederick G. , Benkel Bernard F. , McKay Robert M. , Pelletier Ghislain
Published: March 2010

The obese (ob) gene isolated from ob/ob mice in 1994 is expressed specifically in adipose tissue. The gene product, leptin, regulates food intake, energy expenditure and puberty. Reported herein is a 2477 bp mRNA sequence for the pig obese gene, which includes the complete coding sequence. Two different ob cDNAs were identified, which differed by the inclusion or exclusion of a single glutamine codon at position + 49 of the protein sequence. The pig obese gene encodes a 4.5 kb mRNA transcript, which is specific to adipose tissue. Southern blot analysis of fat and lean pigs showed a DNA polymorphism related to the lean phenotype. Differences in leptin mRNA levels showed that fat pigs have a higher level of leptin mRNA than lean pigs. These findings indicate that pig leptin expression can be associated with subcutaneous fat accumulation in pigs. Key words: Obese gene, polymorphism, mRNA, expression, swine, leptin
Relationships of thyroid hormones, IGF-I and testosterone in breeds of ram lambs with low and high prolificacies
Authors: Fallah-Rad A. H. , Connor M. L.
Published: March 2010

Ten Suffolk (Sfk) and 10 Outaouais (Out) ram lambs were selected to study the relationship between testosterone, thyroid hormones (T3, T4), IGF-I, glucose, semen production and testicular histology at the onset of puberty in lower prolific (Sfk) and higher prolific (Out) breeds. SC, BW, ADG, RG and DM consumption were recorded weekly. Semen was collected by electro-ejaculation from 32 to 35 wk of age and evaluated. Blood was collected weekly by indwelling jugular catheters, every 20 minutes from 0900 to 1520 h to measure the concentration of glucose, T4, T3, IGF-I and testosterone. At wk 35, histological sections of testes were evaluated. Number of spermatozoa in the semen of Out was higher than Sfk (P < 0.01). Average BW, ADG, RG, SC, DM consumption and blood glucose of the two breeds were not different throughout the experiment (P > 0.1). However, there were negative correlations between levels of glucose, T4, T3 and age of the lambs. Testosterone concentrations and pulse frequencies were higher in Out than Sfk (P < 0.05). There were positive correlations between testosterone concentration, testosterone pulse frequencies and age of the lambs in the two breeds. Moreover, level of T4, T3 and IGF-I were higher in Out than Sfk throughout the sampling period (P < 0.01). Although there were fluctuations in the level of IGF-I in the blood, no pulses were detected. Higher levels of testosterone, T4, T3, IGF-I and testosterone pulses in Out may be associated with greater prolificacy in this breed. Key words: Ram lambs, prolificacy, thyroxin, IGF-I, tri-iodothyronine
Growth response of pastured Simmental calves to a high by-pass protein creep supplement
Authors: Jensen D. O. , Okine E. , Goonewardene L. A. , Erichsen-Arychuk C. , Milligan D.
Published: March 2010

One hundred and thirty-seven cow-calf pairs on pasture in southeastern Alberta, were randomly allocated to one of two treatments no supplement (NOS) or a high by-pass protein (70% of CP) creep supplement (HPS) at an intake of 1.5 kg head−1 d−1. Calf weaning weights and pre-weaning ADG were higher (P < 0.01) in calves fed HPS (306.0 kg and 1.49 kg d−1) compared with NOS (298.2 kg and 1.41 kg d−1), respectively. However, it was uneconomical to feed this high by-pass creep as the feed cost of a kg of additional gain at weaning was $9.60. Key words: Creep supplement, pasture, growth, beef cattle
Effect of maceration at mowing on silage conservation,voluntary intake, digestibility and growth rate of steers fed precision chopped or round bale silages
Authors: Charmley E. , Savoie P. , Mcrae K. B. , Lu X.
Published: March 2010

Four silages were made from the primary growth of an orchardgrass (Dactylis glomerata)/white clover (Trifolium repens) sward in mid-June. Precision chopped (PC) and round bale (RB) silages were made from wilted forage that had been cut either with a regular mower conditioner (CON) or a mower macerator (MAC). Silages were fed to growing steers in a 10-wk feeding trial using a 2 × 2 factorial design. To determine apparent digestibility, silages were fed to wether sheep and ruminally incubated in nylon bags using two canulated cows. The DM concentration of silages ranged between 273 and 362 g kg−1 and was higher in RB than PC silage. Maceration increased fibre concentration in RB silage but had little influence on PC silage. Nitrogen and its fractions were not influenced by treatment. Maceration increased total acid concentration in PC silages but lowered it in RB silage. Lactic acid accounted for a higher proportion of total acids in macerated silages than in control silages. Steers fed RB silage consumed 35% more DM than those fed PC silage (P < 0.001). Maceration reduced intake of PC silage by 18% but did not affect intake of RB silage (interaction; P < 0.05). Maceration had no effect on BW gain in steers fed PC silage, but in RB silage gains were increased from 0.87 kg d−1 to 1.09 kg d−1 (interaction; P < 0.05). Feed utilization efficiency was poorer for RB than PC silage (P < 0.001) and maceration improved feed utilization (P < 0.001). The DM, OM and NDF digestibility coefficients were reduced by maceration in RB but not in PC silage (interaction; P < 0.05); a similar trend was observed for ADF (interaction; P < 0.10). Apparent N digestibility was less in MAC than CON silage (P < 0.01). Dry matter disappearance from nylon bags was not influenced by maceration in PC silage but was higher in RB-MAC than RB-CON silage. It is concluded that influences of maceration on intake and gain is dependent upon the physical form of the silage. Key words: Maceration, silage, round bale, precision chop, growth, beef
Fatty and defatted herring scrap fed to mink (Mustela vison) in the reproduction and nursing periods
Authors: Clausen Tove N. , Damgaard Birthe M. , Børsting Christian F. , Hejlesen Carsten
Published: March 2010

The use of fatty herring scrap and defatted herring scrap products for female mink in the reproduction and nursing periods was investigated in two experiments. In exp. 1, diets with 27% fatty herring scrap with 60 vs. 120 mg vitamin E kg−1 feed, and 10 vs. 19% defatted herring scrap ensiled with formic and acetic acids were compared with a control diet without fatty herring scrap or defatted herring scrap silage. Each dietary group consisted of 137 females. In exp. 2, diets with 20% fatty herring scrap with 63 vs. 78% of the dietary fat originating from fish, and diets containing 20 vs. 29% defatted herring scrap were compared with a control diet without fatty herring scrap or defatted herring scrap. Each dietary group consisted of 90 females. The results showed that fatty herring scrap, defatted herring scrap and defatted herring scrap silage can be used at these levels during the winter and reproduction periods until parturition, without any negative effects on the number of kits per female at parturition and weaning. However, use of defatted herring scrap silage in the nursing period resulted in lower kit weights at weaning. There were also some indications that high amounts of dietary fat from herring led to reduced kit weights at weaning; therefore, reducing the fat content in herring seemed to be appropriate in order to reduce the content of fish fat in the diet in the nursing period. The recommended addition of 60 mg vitamin E kg−1 wet feed, with an energy density of 5–6 MJ kg−1 during winter, reproduction and nursing periods, was sufficient according to the plasma content of α -tocopherol. Furthermore, there were no negative effects in the nursing period of feeding fatty or defatted herring scrap during the preceding rearing season of the females. Key words: Mink, marine lipid, polyunsaturated fatty acid, haematology, α -tocopherol, acid silage
A comparison of reproductive and growth traits of horned and polled cattle in three synthetic beef lines
Authors: Goonewardene L. A. , Pang H. , Berg R. T. , Price M. A.
Published: March 2010

The data for the study were obtained over an 11 yr period and the number of observations varied from 2663 to 4263 depending on the trait that was studied. The objective was to compare the reproduction and growth traits of genetically horned and polled cattle in three synthetic lines of beef cattle. No differences (P > 0.05) were observed between horned and polled cattle in all lines for pregnancy, calving and weaning rates, calf birth and weaning weights, calf preweaning average daily gains, dystocia score, cow weights and cow condition scores at calf birth and calf weaning. We advocate the use of polled cattle for breeding, which is a welfare friendly alternative and circumvents the need for dehorning. Key words: Horned, polled cattle, dehorning, reproduction, growath
Investigation into the production and conformation traits associated with clinical mastitis using artificial neural networks
Authors: Yang X. Z. , Lacroix R. , Wade K. M.
Published: March 2010

A data set comprising milk-recording and conformation data was used to investigate the usefulness of artificial neural networks in detecting influential variables in the prediction of incidences of clinical mastitis. Specifically, these data contained test-day records from dairy herd analysis, phenotypic cow scores for conformation and genetic conformation proofs for cows and their sires. The data were analysed using the milk-recording data only, the conformation data only, and a combination of the two. Results from sensitivity analyses, performed with trained neural nets, indicated that stage of lactation, milk yield on test day, cumulative milk yield and somatic cell count were the major production factors influencing the ability to detect the occurrence of clinical mastitis. Among the conformation traits, such variables as phenotypic scores for rear-teat placement, dairy character and size, cow proof for dairy character, sire reliability for final score and sire proofs for pin-setting (desirability) and loin strength were found to have some influence on the network's predictive ability, although they were all very minor in relation to the production variables mentioned. As a group, cow genetic proofs seemed more important than either sire genetic proofs or cow phenotypic scores. Given the neural network's general abilities to determine the major factors related to the presence or absence of mastitis on a given test day, it may be appropriate to investigate the possibility of using this technology for actual prediction purposes. Key words: Artificial neural networks, clinical mastitis, milk-recording data, conformation traits, sensitivity analysis, milk production
Oocyte quality and embryo production in cattle
Authors: Sirard M.-A. , Blondin P.
Published: March 2010

New evidence indicates that bovine oocytes are not always in synchrony with their surrounding follicles. During rapid follicular growth, the oocytes do not acquire a full developmental competence. The plateau phase at the end of the growth phase resulting in dominance or atresia seems important for oocytes to accumulate the information required to become viable embryos. The ovarian follicle has a behavior similar to a fruit where the seed must await the ripening of the envelope to achieve its full potential. This knowledge can now be applied to harvest oocytes of higher quality through transvaginal aspiration in cows. Key words: Oocyte, embryo, cattle
Nutritional value of wheat for growing pigs: chemical composition and digestible energy content
Authors: Zijlstra R. T. , Lange C. F. M. De , Patience J. F.
Published: March 2010

Nutritional value of cereal grains varies greatly, and is currently estimated foremost by measuring density, whereas prediction based on chemical composition might be more useful. Thus, 16 samples of wheat were evaluated for density, chemical composition, and digestibility in growing pigs. The chemical evaluation included analyses for crude protein (CP), amino acids, neutral detergent fibre (NDF), acid detergent fibre (ADF), starch, and monomer sugars in non-starch polysaccharides (NSP). Digestible energy (DE) content was determined with growing pigs (barrows; 40.8 kg ± 5.3). Density ranged from 57.8 to 77.6 kg hL−1, CP concentration ranged from 13.0 to 18.1%, NDF concentration ranged from 12.9 to 25.0%, NSP concentration ranged from 10.5 to 16.6%, xylose concentration ranged from 4.3 to 6.5%, and DE contentranged from 3701 to 4050 kcal kg−1 Results of chemical analyses were expressed on a dry matter basis. Of the characteristics, xylose had the highest correlation with DE (r = −0.78; P < 0.001), and thus was the best single indicator for DE content (R2 = 0.61; P < 0.001), followed by total NSP (R2 = 0.54), and CP (R2 = 0.49). Density did not predict DE content as well (R2 = 0.43). Using two chemical characteristics, CP and NDF together resulted in the best prediction of DE content (R2 = 0.75; P < 0.001). The results indicate that prediction of nutritional value is more accurate based on chemical characteristics than based on density. Key words: Wheat, digestible energy, growing pig, non-starch polysaccharide