bluuebunny/crossref_metadata_2025 huggingface dataset:
Digestible energy, protein and amino acid content in selected short season corn cultivars fed to growing pigs
Authors: Opapeju F. O. , Nyachoti C. M. , House J. D.
Published: April 2011

The digestible energy (DE), ileal digestible crude protein (CP) and amino acid (AA) contents in two corn cultivars commonly grown in Manitoba were determined using six ileal cannulated barrows (average initial BW of 21.5 ± 0.9 kg). Three samples of each cultivar, each obtained from two locations, were evaluated in six dietary treatments in a 2 × 3 factorial arrangement. Diets contained 97% corn and 0.3% chromic oxide as an indigestible marker, and were assigned to pigs in a 6 × 6 Latin square design. Ileal digesta and fecal samples were collected for determining energy and nutrient digestibilities. Location affected (P ≤ 0.05) ileal digestible indispensable AA, except for lysine and threonine. Cultivar affected (P ≤ 0.05) ileal digestible CP and indispensable AA, except for lysine, phenylalanine and valine. There was an interaction effect (P < 0.05) of location and cultivar on ileal digestible indispensable AA, except for lysine and histidine. Digestible energy, CP and AA averaged 3662 kcal kg-1, 5.95% and 0.40%, respectively, in the dry matter. The content of digestible CP and AA in corn may vary with location and cultivar and this variation should be considered when formulating livestock feeds. Key words: Amino acids, corn, digestibility, energy, pig
Effect of mechanical processing of corn silage on in vitro ruminal fermentation, and in situ bacterial colonization and dry matter degradation
Authors: Kozakai K. , Nakamura T. , Kobayashi Y. , Tanigawa T. , Osaka I. , Kawamoto S. , Hara S.
Published: April 2011

Rumen fermentation and bacterial colonization of mechanically processed corn silage were evaluated in a series of in vitro and in situ experiments using ruminally cannulated cows. Data from rumen-simulated continuous culture (Rusitec) showed that total VFA concentration was increased (P < 0.001) by feeding processed corn silage, while pH was reduced (P < 0.001) and ammonia nitrogen remained unchanged (P > 0.05). Mechanical processing enhanced the in situ rate and extent of dry matter disappearance for corn stems and kernels, respectively (P < 0.05). It also enhanced in situ, the initial attachment of rumen bacteria responsible for corn digestion, as monitored by real-time PCR. The16S rDNA copy numbers of amylolytic and lipolytic bacteria, such as Succinivibrio dextrinosolvens, Ruminobacter amylophilus and Anaerovibrio lipolytica, attached to corn kernels were increased for processed corn silage (P < 0.05), in particular at 2 h after the start of incubation. In addition, corn stemattached cellulolytic and hemicellulolytic bacteria, such as Fibrobacter succinogenes, ruminococci and Eubacterium ruminantium, increased in 16S rDNA copy numbers for processed corn silage (P < 0.05). This was observed for the initial incubation period from 10 min to 2 h. These results demonstrate more rapid attachment and heavier colonization of rumen bacteria to the processed compared with the unprocessed silage, which facilitates ruminal digestion and fermentation. Key words: Corn silage, mechanical processing, rumen fermentation, bacteria, attachment
Effects of feeding time on thermoregulation of beef heifers in winter
Authors: Bergen R. D. , Kennedy A. D. , Schwartzkopf-Genswein K. S. , Lawson T.
Published: April 2011

The effects of morning (0900) vs. evening (2000) and natural (< 15 h natural light d-1) vs. extended (65 lux for 16 to 19 h d-1) photoperiod on vaginal temperature, growth rate and feed efficiency were examined in 48 crossbred beef heifers during the backgrounding and finishing periods. The backgrounding and finishing periods were each subdivided into two 28- intervals to relate ambient and vaginal temperature variables to feedlot performance variables. Time of feeding influenced performance and vaginal temperature patterns during the backgrounding period. Although evening-fed heifers spent more hours at vaginal temperatures exceeding daily mean vaginal temperature during the coldest part of the day (feeding time; P ≤ 0.03), morning-fed heifers grew faster and more efficiently than evening-fed heifers during the coldest interval of the backgrounding period (feeding time interval; P ≤ 0.01). Heifers exposed to an extended photoperiod had higher vaginal temperature, particularly in the late morning (0800 to 1100) than heifers receiving natural photoperiod during the finishing period. Results of this study indicated that the benefit of evening feeding on animal performance was more pronounced in cool than in cold weather. Key words: Beef cattle, thermoregulation, evening feeding
The leptin arg25cys affects performance, carcass traits and serum leptin concentrations in beef cattle
Authors: Buchanan F. C. , Van Kessel A. G. , Boisclair Y. R. , Block H. C. , McKinnon J. J.
Published: April 2011

A single nucleotide polymorphism (SNP) in the bovine leptin gene has been associated with carcass traits and elevated gene expression. To examine the relationship between leptin genotype with serum leptin concentration and carcass traits, blood samples were collected 24 h prior to slaughter in 89 head of cattle. Cattle were predominantly of Angus (n = 26), Hereford (n = 31) and Charolais (n = 32) breed types with approximately half homozygous for the T allele or the C allele. Cattle were limit fed to achieve 1 kg d-1 liveweight gain for a 70-d background period while during finishing, animals were fed ad libitum such that half the animals within each breed type were slaughtered at 8 or 12 mm back fat determined by ultrasound. Preslaughter serum leptin and insulin were determined using radioimmunoassays (RIA) specific for cattle and sheep. Animals homozygous for the T allele had greater (P < 0.05) backfat depth at the beginning (2.4 ± 0.49 vs. 1.8 ± 0.49 mm) and end (3.1 ± 0.42 vs. 2.4 ± 0.42 mm) of the backgrounding period and reached target finishing back fat depths at lighter (P < 0.01) weights (548.2 ± 20 vs. 588.0 ± 20 kg) and in fewer (P < 0.05) total days on feed (179.3 ± 13 vs. 195.2 ± 13 d) than homozygous C animals. Leptin genotype effects on serum leptin concentration were confined to a three-way interaction such that TT Charolais fattened to 12 mm had significantly higher serum leptin levels than CC animals. Leptin concentration was correlated positively with measurements of fat (e.g., average ultrasound fat depth at end of test r = 0.45, P < 0.01). Results are consistent with an increased rate of fat deposition associated with the T allele in leptin. Key words: Beef cattle, leptin, carcass, yield
Failure of short-term feed restriction to affect luteinizing hormone and leptin secretion or subcutaneous adipose tissue expression of leptin in the prepuberal gilt
Authors: Hart H. A. , Azain M. J. , Hausman G. J. , Reeves D. E. , Barb C. R.
Published: April 2011

Previously we reported that 24-h fast increased serum non-esterified fatty acids (NEFA) concentrations, and decreased leptin pulse frequency, but not mean serum leptin concentrations in the OVX prepuberal gilt. The present study was conducted to determine if short-term feed restriction in the prepuberal gilt would reduce BF gene transcript expression, pulsatile LH secretion and serum leptin concentrations. OVX prepuberal gilts 79 ± 4 kg BW were control fed 3 kg (CF; n = 6) or feed restricted (RST; 33% of CF diet; n = 6) for 8 d to determine the effects of RST on leptin and LH secretion, metabolism, leptin, Ob-rb and transcription factor expression in BF. Blood samples were collected on day 8 and BF on day 9. RST gilts lost BW (-2.5 vs. +8.2 kg; SE = 0.6 kg; P < 0.001) and BF (-3 vs. +2 mm; SE = 1mm; P < 0.02) compared with CF gilts. Postprandial serum T4 concentrations increased (P < 0.04) in CF, but not in RST pigs. Postprandial serum insulin and BHBA concentrations were similar between treatments. A treatment × time interaction was detected for plasma glucose (P < 0.02) and NEFA (P < 0.04) concentrations. Feed restriction failed to affect leptin or LH secretion except for LH pulse amplitude was greater (P < 0.01) in RST gilts. RST failed to affect BF leptin, Ob-rb, AFABP, C/EBPα, or PPARγ2 expression. In conclusion, the ability of the prepuberal gilt to maintain energy level in the normal range suggests the prepuberal animal is resistant to moderate reduction in nutrition. Thus, leptin may not play a primary role in the regulation of LH secretion in the prepuberal gilt, but may serve as a metabolic signal reflecting the amount of stored energy, which may be necessary for activation of the reproductive axis during puberal development in the gilt. Key words: Leptin, luteinizing hormone, nutrition, adipocyte, pig
Comparisons of amino acid and protein levels in oil-extracted seeds of Brassica and Sinapis species, with observations on environmental effects
Authors: Bell J. M. , Rakow G. , Downey R. K.
Published: April 2011

Seeds from 21 selections of Brassica and Sinapis were analyzed for crude protein (CP; N × 6.25) and amino acid content following oil extraction and grinding. In exp. 1 three cultivars of B. napus, B. rapa and B. juncea were grown in four locations in 4 successive years, with duplicate samples taken from each plot. Brassica juncea contained more CP (P < 0.001) than B. napus or B. rapa (44.6 > 40.1 > 38.8%, respectively). Location affected CP level but not the ranking among cultivars. Year-to-year effects on CP levels (P < 0.001) were of lower magnitude than location effects. Treatments (cultivar, location, year) affected CP and amino acid levels differently. Amino acid levels expressed as percent of CP differed among many cultivars (P < 0.01). Threonine, valine, histidine, lysine and arginine were strongly influenced by location (P < 0.001), as were the dispensable amino acids serine, glutamine and tyrosine. In exp. 2, 10 cultivars and strains grown in one location and in three replicates resulted in greater CP levels in two B. juncea cultivars than in B. napus and B. rapa (42.9 and 43.2 vs. 39.7 and 38.8%), respectively, but lower levels of lysine and threonine in the CP (lysine: 5.4 vs. 6.3; threonine: 3.5 and 3.7 vs. 3.8 and 4.0%). Brassica napus and B. rapa ranked among the lowest in percent CP. In exp. 3, comparisons of eight samples from B. napus, B. rapa and Sinapis alba plots revealed a CP range of 38.1 to 45.0% but differences in amino acid content of the CP were relatively small. Key words: Brassica, Sinapis, protein, amino acids
A dark, firm, dry-like condition in breast meat of roaster chickens condemned for ascites, valgus-varus deformity and emaciation
Authors: Mallia J. G. , Barbut S. , Vaillancourt J-P. , Martin S. W. , McEwen S. A.
Published: April 2011

Chicken carcasses with dark, firm, dry traits (DFD) are currently condemned in Canada for cyanosis. Reconsideration of the current policy requires tests for distinguishing DFD carcasses from those that are inadequately bled. Birds in other categories such as ascites (AS), emaciation (EM), and valgus-varus deformity (VVD) may also present a dark carcass color. Chickens condemned for DFD and inadequate bleeding (IB), and also for AS, EM and VVD were collected, and visually separated into "light" or "dark" groups. Color (Commission Intern. de l'Eclairage L*a*b*) and pH were measured at slaughter, on four fixed sites of the pectoralis major. pH was highly and negatively correlated with L* for AS (r = –0.57), EM (r = –0.64), and VVD (r = –0.66). The dark classes of EM and VVD were not significantly different (P > 0.05) for pH, L*, and a* from DFD carcasses, but the dark AS class was redder and less acidic than DFD carcasses. Color and pH were not correlated in the inadequately-bled group, which was lighter, less red, and more acidic than the DFD group. Tests based on pH and a*, used to distinguish DFD from inadequately bled carcasses, showed good sensitivity and specificity. The agreement beyond chance between the pH and a* tests was good (Kappa = 0.65). We conclude (1) that a DFD-like condition was present in the dark classes of AS, EM and VVD, and (2) that inadequately bled chickens can be distinguished from those with DFD traits by the use of tests based on pH and a*. Key words: Poultry color, rapid tests, chicken, dark firm dry meat, cyanosis
Effect of vasoactive intestinal polypeptide infusion on feed intake, digesta flow and nutrient digestion in sheep with access to feed for limited time
Authors: Li B. T. , Okine E. K. , Christopherson R. J.
Published: April 2011

Two experiments were conducted to test the hypothesis that vasoactive intestinal polypeptide (VIP) infusion into the gastric artery increases feed intake, duodenal flow and amino acid supply to the small intestine of sheep. Four sheep in exp. 1 and five sheep in exp. 2 were fistulated with rumen and duodenal cannulae. Sheep in exp. 2 also had an ileal cannula. In both experiments animals were fed a diet of alfalfa pellets ad libitum for 8 h per day in a thermoneutral environment (20 ± 2 °C) and had free access to water and mineralized salt blocks. In exp. 1, VIP was infused at 1 nmol min−1 through a gastric-artery catheter for 10 min duration each hour for 3 h each day for 4 consecutive days. In exp. 2, VIP was infused at 1.5 nmol min−1 for 10 min duration each half-hour for 3 h each day for 7 consecutive days. Control sheep were infused with saline. Vasoactive intestinal polypeptide infusion increased (P < 0.05) feed intake by 14.3 and 26.1% in exp. 1 and exp. 2, respectively. In exp. 2, there was a positive regression (P < 0.01) between intake and duodenal passage of dry matter (DM) (n = 5, r2 = 0.67), organic matter (OM) (n = 5, r2 = 0.68), and amino acids (AA) (n = 5, r2 = 0.85). The present results suggest that VIP may play a role as a physiological regulator of feed intake in sheep and also has potential to increase the supply of nutrients to the animal. Key words: Digesta passage, intake, sheep, vasoactive intestinal polypeptide
Canola screenings as a fiber source in barley-based feedlot diets: effects on rumen fermentation and performance of steers
Authors: Pylot S. J. , McKinnon J. J. , McAllister T. A. , Mustafa A. F. , Popp J. , Christensen D. A.
Published: April 2011

Two experiments were conducted to determine the feeding value of canola screenings in combination with barley grain for beef steers. Four dietary treatments were used. These included canola screenings:barley grain ratios of 100:0; 75:25, 50:50, and 25:75 (as-fed basis). In a metabolic trial, the effects of dietary treatment on ruminal fermentation parameters were determined in a 4 × 4 Latin square design experiment using four ruminally fistulated steers. In a production trial, 66 individually fed steers were used in an 83-d finishing trial to determine the performance and carcass characteristics of feedlot cattle fed different levels of canola screenings. A barley grain/barley silage-based control diet was also fed for comparison purposes. Ruminal pH decreased (P < 0.05) while total volatile fatty acid concentrations increased (P < 0.05) as the level of barley grain in the diet increased. Ruminal NH3–N followed a pattern (P < 0.05) similar to that of pH. Inclusion level of canola screenings had no effect on DM intake. However, ADG and feed efficiency increased (P < 0.05) as the level of barley grain in the diet increased. Increasing the level of barley grain in the finishing diet decreased (P < 0.05) lean meat yield and increased (P < 0.05) carcass fat. It was concluded that canola screenings can be included as a source of fiber in barley-based diets. However, levels in excess of 500 g kg−1 reduced the performance of feedlot steers. Performance and cost of gain with 250 and 500 g kg−1 canola screenings in barley-based finishing diets were comparable with those fed an 800 g kg−1 barley grain and 200 g kg−1 barley silage diet. Key words: Canola screenings, ruminal fermentation, feedlot steer performance
Effect of adding lignosulfonate and heat to canola screenings on ruminal and intestinal disappearance of dry matter and crude protein
Authors: Keyserlingk Marina A. G. von , Weurding E. , Swift Mary Lou , Wright C. F. , Shelford J. A. , Fisher L. J.
Published: April 2011

The effect of adding 5% calcium lignosulfonate (LSO3) and heat to canola screenings on in situ ruminal and intestinal dry matter (DM) and crude protein (CP) disappearance in Holstein cows was investigated. Treatments consisted of untreated canola screenings, canola screenings that had been heated to 100 °C for 30 or 60 min and canola screenings that had 5% (wt wt−1) LSO3 added and were subsequently heated at 100 °C for 0, 30 or 60 min. Results indicate that treatment of canola screenings with 5% LSO3 and heated to 100 °C for 60 min was effective in reducing rumen degradation of DM and CP with a corresponding increase in disappearance in the lower gastrointestinal tract when compared to untreated and heat-treated canola screenings. Key words: Canola screenings, rumen by-pass protein, heat treatment, lignosulfonate
Genetic trends for weaning weight during development of a multibreed population of beef cattle in two contrasting environments
Authors: Tosh J. J. , Kemp R. A.
Published: April 2011

Genetic trends for weaning weight were determined in two herds of multibreed beef cattle that originated from a common base and were subject to mutual breeding policies in separate environments. The herds diverged for the direct though not the maternal genetic component of weaning weight within the 13-yr period examined; in the final year, the difference (P < 0.001) between the herds was almost 3 kg. This could have been partly due to unequal selection differentials and generation intervals. Results suggested the extent of natural selection also differed between the two environments. Key words: Beef cattle, crossbreeding, genetic trends, selection, weaning weight
Effect of removal of large follicles after artificial insemination on embryo yield of superovulated beef cows
Authors: Otoi T. , Koyama N. , Yamamoto K. , Tachikawa S. , Suzuki T.
Published: April 2011

The removal of large follicles 3 d after AI during induction of superovulation of cows had detrimental effects on the number of transferable and freezable embryos. The removal of large follicles 1 d after AI had no effects on embryo quality. Therefore, this procedure appears not to be beneficial in improving the numbers of embryos available for transfer following superovulation of cattle. Key words: Large follicle, aspiration, superovulation, cow
On-farm phosphorus budget: Model to predict yearly phosphorus contents in manure of dairy herds
Authors: Cynthia Ouellet Isabelle Chaperon, , Girard Vincent , Chorfi Younes
Published: April 2011

In order to reduce soil phosphorus (P) saturation, it is essential to assess the amount of manure P on cultivated soil. The purpose of this study was to estimate yearly herd manure P outputs from production and feeding records with a model based on replacement and dairy animals. The model predicts manure P based on P ingested by dairy cows (kg yr-1), P secreted in milk (kg yr-1), P in calf at birth (kg yr-1), and the number of first-lactation cows. The relationship between first-lactation cows and heifers was established; there were 1.3 ± 0.05 heifers for each first-lactation cow. Manure P from heifers was then obtained by fitting the model to manure P accumulated in concrete pits of 12 farms, measured over two 6-mo periods at 1 yr intervals. The model added 10.6 ± 4.6 kg of P for each first-lactation cow to predict the yearly P output of 1.3 heifers. Ratios between P harvested as feed and P predicted in manure were calculated in 1133 herds. High ratios were obtained in herds with less customized concentrate (P < 0.001), more harvested grain and silage (P < 0.001) on farm and larger size of herd (P < 0.001) with more milk (P < 0.001) and lower calf production (P < 0.001). Decreasing purchased customized concentrates and increasing the amount of silage fed to animals are valid options to reduce non-point-source P pollution. Key words: Dairy herds, manure, phosphorus, model, reproductive efficiency
Dietary n-3 fatty acids decrease the leukotriene B4 response ex vivo and the bovine serum albumin-induced footpad swelling index in New Hampshire hens
Authors: Hall J. A. , Jha S. , Cherian G.
Published: April 2011

The effects of feeding New Hampshire hens different amounts of n-6 and n-3 fatty acids on plasma and immune tissue fatty acid profiles, leukotriene (LT) B4 response ex vivo in stimulated thrombocytes, serum non-esterified fatty acid (NEFA) concentrations, and bovine serum albumen (BSA)-induced footpad swelling index were investigated. Seventy-two New Hampshire hens (n = 24/treatment) were fed diets supplemented with 3.0% sunflower oil (Diet I), 1.5% sunflower oil + 1.5% fish oil (Diet II), or 3.0% fish oil (Diet III). After 46 d on experimental diets, concentrations of C20:5n-3 and C22:6n-3 were higher in plasma, thrombocytes, and spleens of hens fed Diet II and III compared with hens fed Diet I (P ≤ 0.05). Thrombocytes from hens fed Diet III that were stimulated ex vivo with calcium ionophore A23187 produced less LTB4 than those from hens fed Diets I and II (P < 0.05). The serum NEFA concentrations were 0.31 ± 0.12, 0.25 ± 0.08, and 0.17 ± 0.06 mEq L-1 for hens fed Diets I, II, and III, respectively (P = 0.07). The cell-mediated immune response, based on results of a BSA-induced footpad swelling index at 48 h, was less in hens fed Diet III (P < 0.05) compared with hens fed Diets I or II. These results indicate that increasing the concentration of n-3 fatty acids in diets fed to New Hampshire hens might depress cell-mediated immunity and the pro-inflammatory LTB4 response. Key words: N-3 fatty acids; Leukotriene B4; Thrombocytes
Temperature preference in piglets weaned at 12–14 days of age
Authors: Bench Clover J. , Gonyou Harold W.
Published: April 2011

Five replicates of 48 pigs each, weaned at 12–14 d of age, were observed. Mean preferred temperature was found to decrease during the night and early morning, and increase during the day. Average preferred temperatures were 26.3°C, 25.7°C, and 25.3 °C for 3, 4, and 5 wk of age, respectively. Key words: Temperature preference, pigs, early weaned, operant conditioning
Past peak lactational performance of Iranian Holstein cows fed raw or roasted whole soybeans
Authors: Fathi Nasri M. H. , Danesh Mesgaran M. , Kebreab E. , France J.
Published: April 2011

Responses of past peak lactating Iranian Holstein cows to feeding roasted whole soybean (SB), raw SB or soybean meal (SBM) supplements were evaluated. Treatments consisted of a total mixed ration (TMR) with 34% forage (21% alfalfa hay and 13% corn silage) supplemented with 11.9% SBM or 13.3% roasted SB or raw SB. Diets were offered to 18 multiparous cows assigned randomly to one of three experimental diets for a 49-d trial. Dry matter intake was not significantly different, but total and fat-corrected milk yields were higher for cows fed the roasted SB diet than the other treatments. Milk fat concentration was not significantly different among treatments, but milk fat yield was significantly higher for cows fed the roasted SB and SBM diets. Milk protein concentration was significantly decreased by the raw and roasted SB diets, but milk protein yield was unaffected. Feeding roasted SB significantly reduced rumen ammonia N, plasma urea N and milk urea N concentrations. Ruminal pH, plasma glucose and beta-hydroxybutyrate concentrations were not affected. Compared with the other treatments, roasted SB increased plasma concentration of most essential amino acids, except leucine and phenylalanine. Although caution must be taken in the interpretation of the results due to the limited number of observations in the experiment, feeding roasted SB in a diet with alfalfa hay as the primary forage was beneficial. Key words: Whole soybean, lactational performance, blood metabolite, dairy cows
Patterns of maternal-offspring behaviour of dairy sheep and potential association with mammary health
Authors: Gougoulis D. A. , Kyriazakis I. , Mavrogianni V. S. , Fragkou I. A. , Skoufos J. , Tzora A. , Taitzoglou I. A. , Kokoli A. N. , Fthenakis G. C.
Published: April 2011

Behaviour during lactation and its relationship with mammary health was investigated in 12 dairy ewes (six with single lambs and six with twins) for 42 d after lambing. Behavioural recordings were made. Samples of teat duct material and of mammary secretion were collected for bacteriological and cytological examination. Ewes performed similar patterns of behaviour as those described in the literature for meat breeds, but with some differences. No negative maternal behaviours were observed; ewes showed reduced “Grooming” and “Sniffing” immediately post-partum. Of 480 duct or secretion samples, 39 and 3, respectively (P < 0.001), yielded bacteria. There was no difference in the frequency of bacterial isolation from ewes suckling singles or twins: 46 and 54% of isolates, respectively (P = 0.637). There was greater frequency of bacterial isolation during the first stage of lactation (day 0–day 3), 0.125, compared with the second (day 4– day 11), 0.083, the third (day 12–day 30), 0.063, and the fourth (day 31–day 42), 0.069 (P < 0.001). There was also greater frequency of positive California Mastitis Test scores during the first stage of lactation, 0.917, compared with that in stages 2 (0.550), 3 (0.140) and 4 (0.181) (P < 0.001). There was decreasing duration of “Sucking attempt” and “Successful suck” throughout lactation (P < 0.05). There was increasing frequency of “Hindering sucking” and of “Head up posture” from first to subsequent stages of lactation (P = 0.038 and P = 0.002), whilst “Hindering sucking” coincided with end of “Sucking bouts” of lambs. It is concluded that termination of lamb’s sucking activity by the ewe when her mammary glands have been emptied may prevent damage to the teat and likely development of mastitis. Furthermore, frequent and longer sucking events by lambs during early lactation, may contribute to increased bacterial recoveries from mammary glands of ewes. Key words: Sheep, maternal behaviour, mastitis, sucking, post-partum period, lactation, mammary infection
Effect of α-tocopherol on in vitro culture of bovine embryos
Authors: Marques A. , Antunes G. , Santos P. , Chaveiro A. , Moreira da Silva F.
Published: April 2011

Bovine oocytes were matured and fertilised under 5% CO2. Presumptive zygotes were co-cultured in synthetic oviductal fluid droplets, supplemented with either 0 (control), 25, 50, 100, or 200 µM of α-tocopherol. Blastocyst development rates were significantly influenced (P < 0.05) by the level of antioxidant in the culture media. Control showed a blastocyst yield of 18.46, 21.11, 27.92, and 31.66%, respectively, at α25; α50 and α100. Blastocyst yield for α200 was severely decreased, to 8.01%. An increase in overall IVF results was also observed as the concentration of α-tocopherol increased (control, 14.21%; α25, 14.35%; α50, 19.52%; α100, 21.11%), decreasing to 5.75% for the concentration of α200. The present study clearly demonstrates that α-tocopherol at a concentration of 100 µM significantly improves the proportion of oocytes that develop to the blastocyst stage. Key words: Antioxidant, α-tocopherol, reactive oxygen species, bovine, embryo
Response of broilers to feeding low-calcium and total phosphorus wheat-soybean based diets plus phytase: Performance, digestibility, mineral retention and tibiotarsus mineralization
Authors: Catalá-Gregori Pablo , García Victoria , Madrid Josefa , Orengo Juan , Hernández Fuensanta
Published: April 2011

A 42-d trial was conducted with broilers fed a wheat-soy bean-meal-based diet to compare three dietary levels of calcium (Ca) and total phosphorus (TP) plus phytase on growth performance parameters, nutrient digestibility, mineral retention and tibiotarsus bone parameters. Three treatments were compared: a high Ca and TP diet (H−; according to NRC recommendations) without addition of phytase; a moderate Ca and TP diet (M+) with 600 U kg-1 of phytase; and a low Ca and TP diet (L+; similar to local industry practices) with 600 U kg-1 of phytase supplementation.

Feed intake and weight gain of broilers fed H− were not different to M+ or L+. Nutrients digestibility at 21 d was improved in animals fed M+ in comparison with H− and L+. Better phosphorus retention was observed for M+ at 21 d of age. The bone mineralization was similar for H− and M+ at 21 d of age, and for H−, M+ and L+ at 42 d of age.
Effects of dietary supplements of folic acid on reproductive performance in ewes
Authors: Méthot H. , Girard C. L. , Matte J. J. , Castonguay F. W.
Published: April 2011

The objective of this project was to assess the impact of periconceptional folic acid supplementation on the reproductive performance of prolific and non-prolific ewes, in the estrous and anestrous seasons. Two initial trials took place during the estrous season at two experimental sites where 38 Dorset and 39 half-Finn half-Dorset ewes (site A) as well as 80 Dorset ewes (site C) were divided into two groups receiving either 0 or 210 mg ewe-1 d-1 of folic acid over a period which extended from 21 d premating to 30 d postmating. Three other trials were conducted in the anestrous season where 80 Dorset ewes (site A), 56 half-Romanov ewes (site B) and 78 Dorset ewes (site C) were subjected to the same protocol as the one used in the breeding season. In all the trials, the folic acid supplement increased plasma and red cell folates, but had no effect on fertility, embryonic mortality, or the size or weight of the litter at birth. Folic acid supplementation did not improve the reproductive performance of prolific and non-prolific ewes, either in the estrous season or in the anestrous period. Key words: Ewes, reproduction, vitamins, folic acid, fertility, prolificacy
Starch and energy digestibility in weaned pigs fed extruded zero-tannin faba bean starch and wheat as an energy source
Authors: Wierenga K. T. , Beltranena E. , Yáñez J. L. , Zijlstra R. T.
Published: April 2011

Digestion of extruded starch is poorly characterized. Two diets containing wheat or faba bean starch were extruded individually or combined 50:50 (wt/wt) and fed to weaned pigs. Ileal starch digestion tended to be higher (P < 0.10) for the extruded wheat diet than the extruded faba bean diets, while total tract digestibility of starch and energy was higher (P< 0.05) for the two extruded faba bean starch diets than the extruded wheat diet. Feed intake tended to be higher (P < 0.10) for extruded faba bean starch diet, but final body weight was not affected by extruded starch source. The in vivo kinetics of starch and energy digestion differed between extruded wheat and faba bean starch diets. Key words: digestibility, extrusion, faba bean, starch, weaned pig, wheat
Effects of supplementing layer hen diets with selenium and vitamin E on egg quality, lipid oxidation and fatty acid composition during storage
Authors: Mohiti-Asli Maziar , Shariatmadari Farid , Lotfollahian Houshang , Mazuji Mohamad Taghi
Published: April 2011

A 7-wk trial was carried out to investigate the effect of vitamin E and inorganic and organic selenium added to hens' diet on quality and lipid stability of eggs during storage. One hundred forty-four Hy-Line W-36 hens (63-wk of age) were divided into six equal groups. Five groups received a basal diet supplemented with 0.4 mg kg-1 sodium selenite or selenium yeast, 200 mg kg-1 vitamin E or a combination of selenium and vitamin E; whereas the control group received no supplementation. Hen production was assessed daily and fresh egg quality parameters were determined every 2 wk. Eggs were stored under different conditions (4°C, 23–27°C or 31°C) for 14 d. Eggs were analyzed for quality characteristics, egg component weight, Malondialdehyde values as a secondary oxidation product and yolk fatty acid (FA) composition. The performance of the hens and egg weights were not affected either by the source of the selenium or by the vitamin E. The inclusion of selenium or vitamin E in the diet significantly increased their concentrations in the egg. The supplemented diets also improved egg quality, oxidative stability and fatty acid composition during storage. Key words: Vitamin E, selenium, lipid peroxidation, egg fatty acid composition, storage
Decreased fertility with increasing parity in lactating dairy cows
Authors: Balendran A. , Gordon M. , Pretheeban T. , Singh R. , Perera R. , Rajamahedran R.
Published: April 2011

The relationships of parity and progesterone (P4) concentrations during the bred cycle with pregnancy rate (PR) were examined in this study. Breeding records of 163 Holstein heifers and cows (in 1st parity, 2nd parity, and 3rd or 4th parity) from the Uuniversity of British Columbia Dairy Education and Research Centre were used to compare PR among heifers, 1st, 2nd and 3rd/4th parity cows. Blood or milk samples collected from 10 animals of each treatment group were assayed to compare P4 concentrations among treatment groups. Statistical analysis showed that the heifers' first insemination PR (67.9%) was higher (P < 0.05) from 1st parity (42.9%), 2nd parity, (20.0%) and 3rd/4th parity cows (11.9%). P4 concentrations were not significantly different (P > 0.05). Key words: Pregnancy rate, progesterone, parity, cows, heifers
Effects of postpartum energy intake on pregnancy rates in beef cattle subjected to GnRH- or CIDR-based timed artificial insemination protocols
Authors: Wichtel J. J. , Charmley E. , Richardson G. F. , Duynisveld J. L. , Lofstedt R.
Published: April 2011

The objectives were to determine the effects of three levels of postpartum metabolisable energy (ME) intake on pregnancy rates in beef cattle subjected to either GnRH-based (OVS) or progestin-based (CIDR) protocols for fixed time artificial insemination (TAI). Hereford cross cows were assigned to ME and TAI treatments (within ME) on the basis of parity and predicted calving date. The postpartum grass-silage-based diet was formulated to provide either Low (93 MJ d-1), Medium (103 MJ d-1) or High (120 MJ d-1)] ME from calving (January to February) to turnout (May 25). Lactating cows [n = 175, 5.7 ± 1.1 mean (± SD) body condition score at calving] were subjected to their assigned TAI protocol; OVS [i.m. treatments of GnRH (100 μg) on day 0, PGF2α (25 mg) on day 7, a second GnRH on day 9 and TAI 16 to 18 h later], or CIDR [i.m. treatment with 1 mg estradiol benzoate and 100 mg progesterone concurrent with CIDR (1.9 g progesterone) insertion on day 0, PGF2α treatment at CIDR removal on day 7, a second estradiol treatment on day 8 and TAI 28 to 30 h later). Cows were 60 ± 13 d post-partum at the time of insemination. Lower ME intakes reduced (P < 0.05) maternal body weight and calf weight gain, but ME intake did not affect (P > 0.05) the proportion cycling (113/175 = 65%, based on serum progesterone concentrations on days -5 and -14), ovulation following TAI, or the TAI pregnancy rates (based on ultrasonography). Timed insemination pregnancy rates were greater for CIDR- than OVS-treatment (63 vs. 45%, respectively, P < 0.05), regardless of ME intake. Key words: Beef cow, estrus synchronization, Ovsynch, CIDR, energy intake, reproduction, calf gains
Estimation of carbon dioxide production and energy expenditure of grazing cattle by the sulphur hexafluoride (SF6) tracer gas technique
Authors: Stewart A. A. , Undi M. , Wilson C. , Ominski K. H. , Wittenberg K. M.
Published: April 2011

The purpose of the study was to explore the suitability of the sulphur hexafluoride (SF6) tracer gas technique to estimate CO2 production and energy expenditure (EE) for grazing animals on pastures typical of western Canada. During each year of a 3-yr study, CO2 emissions were collected from 60 yearling steers on grass pastures receiving one of three fertility treatments: no manure, liquid hog manure applied as a split application (74 kg available N ha-1) in the spring and fall, and a single application of liquid hog manure applied at a rate of 155 kg available N ha-1 each spring. The mean CO2 production estimate across all treatments was 5424 ± 2218 L d-1 (mean ± SD) with a range of 1099 to 11548 L d-1. When compared across three grazing periods in June, July and August, steers produced more (P < 0.05) CO2 in June than in either July or August. Metabolic body weight (BW0.75), average daily gain (ADG), standing forage biomass, and forage neutral detergent fibre (NDF) and crude protein (CP) contents explained 33% of the variation in CO2 production. Energy expenditure (EE) was estimated from CO2 production by adopting an energetic equivalent of 22 kJ L-1 CO2 and EE was calculated for animals that were not losing body weight at time of measurement. The average EE estimate was 1.2 ± 0.5 MJ kg-1 BW0.75 d-1 with a range of 0.2 to 2.8 MJ kg-1 BW0.75 d-1. Energy expenditure declined as ADG and forage biomass declined, but EE was not influenced (P > 0.05) by fertility treatment. The EE estimate was higher (P < 0.05) early in the grazing season (June) and declined as the grazing season progressed. The SF6 tracer gas technique was able to estimate EE of individual animals without interfering with herd dynamics. The technique was also able to show differences in EE in response to pasture conditions. The results of this study suggest that the SF6 tracer gas technique shows potential as a simple and non-invasive method of estimating CO2 production and EE for grazing animals. Further validation under different grazing conditions and with animals undertaking different degrees of activity is required. Comparisons with other field techniques of estimating EE are also important. Key words: Energy expenditure, carbon dioxide, sulphur hexafluoride, grazing animals
The effect of dry period length reduction to 28 days on the performance of multiparous dairy cows in the subsequent lactation
Authors: Pezeshki Adel , Mehrzad Jalil , Ghorbani Gholam R , De Spiegeleer Bart , Collier Robert J , Burvenich Christian
Published: April 2011

In a controlled study, the effects of shortened and conventional dry periods (28.2 ± 4.6 vs. 48.8 ± 4 d) on performance of multiparous cow were evaluated. Seventy multiparous Holstein cows were randomly assigned to either a 28- or a 49-d dry period length (DPL). Nine cows were removed from the study and 61 cows were used in the statistical analysis. Cows in the 28-d DPL group were moved to close-up pen and fed only close-up ration during the dry period, whereas those in the 49-d DPL group were given a far-off diet after dry-off until 28 d before expected calving, and then fed the same diet as the cows in the 28-d DPL group. Daily milk yield production was significantly reduced in the 28-d DPL group compared with the 49-d DPL group through 210 d in milk (DIM). Neither milk protein nor milk fat was changed in experimental groups. However, fat yield tended to be greater in the 49 d DPL compared with the 28 d DPL. Cows with 28 d DPL lost less body condition in peripartum and gained more body condition score (BCS) by 150 DIM. No differences were detected in health disorders, reproduction efficiency and birth weights of calves due to shortened dry period. Our data demonstrate that a shortened dry period under employed management practices is a good management tool in attenuating negative energy balance status without adversely affecting total milk production. Key words: Dry period, management, multiparous dairy cow, performance, body condition score
Stx2 from enterohemorrhagic Escherichia coli O157:H7 promotes colonization in the intestine of cattle
Authors: Baines Danica , Erb Stephanie , McAllister Tim
Published: April 2011

Cattle act as the main reservoir for enterohemorrhagic Escherichia coli O157:H7, a bacterium that causes serious human disease outbreaks. It is currently not clear which bacterial or animal factors contribute to E. coli O157:H7 colonization in cattle. We recently identified mucosal hemorrhages in the jejunum, ileum and colon of persistent shedding cattle that were associated with E. coli O157:H7 colonization. This suggested that E. coli O157:H7-secreted cytotoxins may be involved in the E. coli O157:H7 colonization process. Further studies confirmed that E. coli O157:H7-secreted cytotoxins were toxic to cattle enterocytes and enhanced E. coli O157:H7 colonization of intestinal tissues. The current study examined the contribution of Stx2 to the earlier reported E. coli O157:H7- associated mucosal damage and secreted cytotoxin activity. Stx2 was not cytotoxic to enterocytes, but did enhance E. coli O157:H7 adherence to intestinal tissues in cattle. This is the first report of an E. coli O157:H7 virulence factor that can directly influence the E. coli O157:H7 colonization process in cattle. Key words: Stx2, Escherichia coli O157:H7, cattle, intestine, colonization
Sustainable pasture based dairy systems – meeting the challenges
Authors: Ferris C. P.
Published: April 2011

This review paper examines a number of the challenges of pasture-based dairy systems. Ensuring adequate nutrient intakes of highyielding dairy cows within grazing systems is one of the key challenges being faced by many dairy farmers. Options examined to increase nutrient intakes include: increasing herbage allowances, manipulating sward structure, modifying herbage composition, and the use of both forage and concentrate supplements. The potential to achieve high levels of animal performance with grazed grass combined with high levels of concentrate supplementation is examined, while forage supplements appear to offer much less scope by which to increase nutrient intakes. Low levels of herbage utilization provide another challenge on many farms, with options to extend the grazing season and to improve early-season forage utilization examined. The results of a whole systems approach to achieving high total nutrient intakes with grassland-based systems are highlighted. The potential to improve the sustainability of dairy systems through breed substitution and by identifying more appropriate strains of Holstein animals for use within grazing systems is also examined. A number of environmental challenges associated with grazing systems together with possible opportunities to reduce their impact are highlighted. These include reducing inputs of inorganic fertilizer nitrogen, reducing the crude protein content of concentrate feedstuffs offered during grazing, and reducing the phosphorus content of dairy cow diets. Key words: Dairy cows, grazing, herbage utilization, dairy breeds, environment
Responses of Medicago sativa and M. falcata type alfalfas to different defoliation times and grass competition
Authors: Hendrickson John R , Liebig Mark A , Berdahl John D
Published: April 2011

Incorporating alfalfa into rangelands can enhance the quantity and quality of forage production. We evaluated the impact of clipping timing and selective clipping on two M. falcata (Anik and Yellowhead) and one M. sativa type alfalfas (Vernal) near Mandan, North Dakota, USA. Cultivars were space-planted into an existing mixed grass prairie and clipped at the mid-bud, flower or flower and subsequent vegetative stages. In each clipping treatment, half of the plots had only the alfalfa clipped and half had both the alfalfa and the associated native vegetation clipped. Plots without alfalfa were also included to evaluate the impact of alfalfa on grass and forb biomass. Including Yellowhead increased total productivity by 38 to 185% without lowering the productivity of the grass or forb biomass components. Plots with Yellowhead produced 17 to 26% more total biomass than the next highest entry every year. In 2003 and 2005, alfalfa biomass was increased 1.5 to 2.7 times by clipping only alfalfa in the flower and regrowth stages compared with a mid-bud clipping of only alfalfa. Vernal and Yellowhead generally produced more total biomass when clipping was deferred to the flower stage, but clipping Anik in the mid-bud stage produced as much or more total biomass than did the later clipping treatments. Selective clipping of the alfalfa did not have a consistent impact on yield. Yellowhead appeared to be a good choice for incorporating into rangelands. Producers with Yellowhead or Vernal should consider delaying defoliation until flowering to maximize productivity. Key words: Grazing-type alfalfa, hay-type alfalfa, defoliation timing, biomass productivity
Monitoring corn and soybean agroecosystems after establishing no-tillage practices in Québec, Canada
Authors: Whalen Joann K , Prasher Shiv O , Benslim Hicham
Published: April 2011

The conversion to no-tillage (NT) may seem risky to some producers who rely on tillage to control weeds, some insect pests and disease-causing pathogens that can reduce crop yield. Weeds, arthropods, and disease incidence were monitored in silage corn (Zea mays L.) and soybean (Glycine max L. Merr.) agroecosystems with CT and newly established NT plots in Ste-Anne-de-Bellevue, Québec. During the first 2 establishment years, there were more annual grass and fewer annual broadleaf weeds in NT than in CT plots, but the surface area covered by weeds (broadleaf,grasses and perennials) was greater in CT than NT plots. Foliar arthropods were more numerous in soybean than corn plots in both years, but were unaffected by tillage. There were more ground-dwelling generalist predators, especially Coleoptera and Carabidae, in CT than NT plots, while spiders and harvestmen (Araneae and Opiliones) were dominant in NT plots. Crop damage from insect pests and diseases was below economic thresholds, but 5 yr of yield monitoring (2000–2004) revealed a trend of greater silage corn and soybean yields in CT than NT plots. The reduction in crop yield after establishing NT practices at this site was probably due to rooting constraints from inadequate seedbed preparation in the NT system, rather than from weed competition, insect damage or crop diseases. Key words: Arthropods, crop disease, silage corn, soybean, tillage, weed control
Genetic analysis of net blotch resistance in a two-row × six-row cross of barley, using doubled-haploid lines
Authors: Cherif M. , Rezgui S. , Devaux P. , Harrabi M.
Published: April 2011

The effect of spike type on net blotch resistance is not fully understood in barley (Hordeum vulgare L.). A doubled-haploid barley population derived from a cross between a susceptible two-row (Roho) and a resistant six-row (line 90) genotypes was used to study the genetics of net blotch resistance and to determine the effect of spike type on net blotch resistance at the adult plant growth stage across three environments. Net blotch rating was evaluated using a mass disease index, area under the disease progress curve and the apparent infection rate. Partial resistance to Pyrenophora teres was observed in many DH lines and in the parental line 90 in the three environments. This result indicated that selecting for partial resistance is feasible under severe net blotch conditions where differential responses among DH lines were noted as in Mograne in 2003–2004. The normality test and/or the means comparison method suggested that additive × additive epistasis effects influenced the expression of all disease parameters in the three environments. Both the coefficient of skewness and the number of transgressive lines indicate the presence of a complementary gene interaction for most disease parameters. Results showed that two-row lines were particularly associated with net blotch resistance in Mograne 2002–2003 and in Tunis greenhouse 2004. A strategy for improving the level of quantitative resistance to P. teres in later generations is recommended. Key words: Hordeum vulgare, doubled-haploid population, quantitative resistance, Pyrenophora teres, net blotch, genetic analysis