bluuebunny/crossref_metadata_2025 huggingface dataset:
Cortisol, progesterone and β-endorphin response to stress in calves
Authors: Cooper C. , Evans A. C. O. , Cook S. , Rawlings N. C.
Published: March 2010

In evaluating stress in farm animals, it would be useful to know whether there were consistent endocrine responses that could be followed. Adrenal cortisol secretion is quite variable, but β-endorphin secretion and adrenal progesterone production may be useful indicators of stress. Changes in plasma concentrations of cortisol, β-endorphin and progesterone were studied in spring-born, castrated male calves (steers) (6 mo of age ± 18 d, 516 ± 26 kg, n = 12) subjected to the stress of routine dehorning. Steers were isolated from their dams for 2 h before headgate restraint (control) or restraint and dehorning. They were bled 60 and 10 min prior to headgate restraint or restraint and dehorning. Blood samples were also collected immediately after headgate restraint or restraint and dehorning (time 0) and 5, 10, 30 and 60 min later. All blood samples were taken from a jugular catheter, and the blood sampling that was done out of the headgate involved minimal manual restraint. Plasma β-endorphin concentrations were similar in control steers and dehorned steers (P > 0.05) and decreased significantly following restraint or restraint and dehorning (P < 0.05). Plasma cortisol concentrations rose significantly 5 min after dehorning and were elevated for 60 min; but with restraint only, plasma cortisol concentrations rose to a peak 5 min after release from chute restraint and then declined (P < 0.05). Plasma cortisol concentrations were greater in dehorned steers than in control steers in the period from 10 min after dehorning or headgate restraint to 60 min after headgate restraint (P < 0.0043). Plasma progesterone concentrations rose to a peak 10 min after dehorning and then declined, but in control steers, a peak was seen at 5 min after release from restraint (P < 0.05). Plasma progesterone concentrations were greater in dehorned steers between 5 and 60 min after dehorning than in control steers (P < 0.05). From these data, we concluded that in prepubertal, castrated male calves, β-endorphin was not released in any significant quantities in response to the stress of dehorning. In steers, adrenal cortisol and progesterone were secreted in response to acute stress, and a ratio of the two may provide a useful assessment of stress; this requires further study. Key words: Cortisol, progesterone, β-endorphin, stress, calves
The effect of feed restriction and of a β-adrenergic agonist on plasma melatonin concentrations in domestic pigs
Authors: Peacock A. J. , Thacker P. A. , Kirkwood R. N. , Tedesco S.
Published: March 2010

The objective of the present study was to determine the effect of feed restriction and a β-adrenergic agonist (isoproterenol) on plasma melatonin concentrations in domestic pigs. At the vernal equinox, eight prepubertal Yorkshire × Landrace gilts (68.9 ± 1.3 kg) were transferred to a barn with natural lighting. Supplementary lighting (minimum of 150 lx) was provided from 07:00 to 16:00 daily. During an 18-d adaptation period, gilts were fed to appetite twice daily on a ration containing 16% crude protein. The feed intake of four gilts was then reduced to 30% of the to-appetite level for the next 7 d. Blood samples were taken from all gilts hourly for 8 h from 21:00 (dark) and again from 09:00 (light) for melatonin analysis. Gilts were then given an i.v. infusion of 0.5 mg kg−1 isoproterenol at 20:00 and 21:00. Blood samples were taken hourly from 21:00 to 24:00 and again at 10:00 and 11:00 the following morning. Plasma melatonin concentrations were higher during the night than during the day in both feed-restricted gilts (P = 0.06) and gilts fed to appetite (P = 0.18). There was no significant effect of feed intake on plasma melatonin during the night (44 ± 2 vs. 38 ± 3 pg mL−1 for restricted and ad libitum gilts, respectively, P = 0.6), but daytime concentrations of the hormone were higher in feed-restricted gilts than in their counterparts fed to appetite (29 ± 2 vs. 22 ± 1 pg mL−1, P = 0.03). Melatonin concentrations tended to be higher at night following isoproterenol treatment in feed-restricted gilts than in the samples taken 24 h earlier (72 ± 12 vs. 47 ± 6 pg mL−1, P = 0.12) but did not differ in gilts fed to appetite (50 ± 14 vs. 40 ± 12 pg mL−1, P = 0.60). These data indicate that plasma melatonin concentrations in the domestic pig may be influenced by nutrition and that the physiological systems governing melatonin secretion in the pig do not differ fundamentally from those of other species. Key words: Melatonin, pineal gland, pig, seasonality, isoproterenol
Evaluation of moist heat treatment of canola meal on digestion in the rumen, small intestine, large intestine and total digestive tract of steers
Authors: Nia S. A. Moshtaghi , Ingalls J. R.
Published: March 2010

The effect of heat treatment on canola meal (CM) dry matter (DM) and nitrogen (N) degradability in the rumen and digestion in the small and large intestines and total digestive tract of steers was determined. CM was moist-heat-treated at 127 °C for 15 and 45 min. The degradation of DM and N was estimated using small nylon bags in the rumen for 0.1, 4, 8, 12, 16, 24, 48 and 72 h. The mobile bag technique with an in vitro incubation in an acid-pepsin solution was used with a separate set of bags to estimate the digestion of each nutrient in the small and large intestines as well as the total digestive tract for rumen incubation times of 8, 16 and 24 h. Chemical analysis of heated CM showed a significant reduction in soluble N, sucrose and glucosinolate content while the concentration of ADIN increased. Treatment significantly reduced the degradation of DM and N in the rumen while the digestibility of DM and N in the small intestine increased with both treatments proportional to the decreased rumen degradation. Heat treatment had no effect on DM and N digestibility at the large intestine site. Total tract disappearance of DM and N were not affected by 15 min heating; however, after 45 min heating, DM and N disappearances were reduced. Moist heat treatment was effective in reducing rumen disappearance of CM nitrogen while it increased the N digestion in the small intestine. Key words: Heat treatment, canola meal, ruminant intestine, protein digestion
Comparison of lignosulfonate-treated canola meal and soybean meal as rumen undegradable protein supplements for lambs
Authors: Stanford K. , McAllister T. A. , Xu Z. , Cheng K.-J. , Pickard M.
Published: March 2010

An experiment was undertaken to determine the effect of lignosulfonate (LSO3) treatment on the rumen-undegradable protein (RUDP) value of canola meal (CM) and soybean meal (SM). Canola meal and SM were treated with 7% LSO3 and heated (95 °C) for 1 h. Treated and untreated meals were compared in vitro, in situ and in digestibility and growth experiments using Romanov × Suffolk and Romanov × Dorset lambs. Lambs were fed four barley-based diets [13.5% crude protein (CP)] with one of CM, SM, LSO3-treated CM (LSO3-CM) or LSO3-treated SM (LSO3-SM) as protein supplements. Lignosulfonate treatment increased acid detergent insoluble nitrogen (ADIN) five-fold in SM and threefold in CM. After 6 h incubation with ruminal fluid, ammonia production from LSO3-treated meals was one-half that from untreated meals. Lignosulfonate treatment reduced (P < 0.01) in situ rates of dry matter (DM) and protein disappearance and the soluble DM and protein fractions for both SM and CM, but not the potentially digestible fractions. No differences in feed conversion or average daily gain (P > 0.05) were found among the treatments. Although LSO3 treatment did not improve the ADG of lambs fed barley-based diets, it increased the RUDP value of SM and CM without adverse effects on digestibility. Key words: Lignosulfonate, canola meal, soybean meal, lamb
Effect of adjuvant on somatostatin (SRIF) antibody production in calves
Authors: Mears G. J.
Published: March 2010

Production of SRIF-antibodies was determined in 18 steer calves immunized against SRIF-conjugate prepared in Freund's, Alhydrogel or Havlogen adjuvant. Freund's adjuvant elevated (P < 0.05) antibody titers between the first booster (wk 6) and termination (wk 24) of the experiment. Alhydrogel and Havlogen adjuvants also elevated (P < 0.05) titers, but only between wk 8 and 10. Key words: Somatostatin, SRIF, adjuvant, SRIF-immunization, SRIF-antibody
In situ degradabilities of barley grain cultivars
Authors: Lehman K. B. , Okine E. K. , Mathison G. W. , Helm J.
Published: March 2010

Differences in in situ dry matter degradabilities occurred at all incubation times when 22 cultivars of barley gram grown at three locations were examined. Rapidly and slowly degradable fractions ranged from 25 to 40% and from 49 to 65%, respectively. Rates of degradation ranged from 23 to 35% h−1 (P = 0.03). Key words: Barley, cultivars, in situ, degradability, location
Protein quality and metabolizable energy yield of pork loin are not affected by cooking
Authors: Emmert Jason L. , Hortin Audra E. , Han Yanming , Baker David H.
Published: March 2010

In a chick growth assay, the protein quality (PER) of pork loin was not affected by roasting, but both raw and roasted pork loin produced higher PER values than that obtained with dehulled SBM. True metabolizable energy, assessed in a precision-fed cockerel assay, was similar for raw and roasted pork loin. Key words: Protein quality, energy yield, pork loin, cooking, chicks
Stomach cannulation of pregnant gilts for nutrition studies during lactation
Authors: Pluske J. R. , Cegielski A. C. , Aherne F. X. , Williams I. H.
Published: March 2010

The design, manufacture and insertion of a cannula into the stomach of first-litter gilts to facilitate superalimentation during lactation is described. Anaesthesia, surgery, and the presence of cannulas had no detrimental effects on birth parameters or on the gilts' ability to lactate and suckle their young. Stomach cannulation enabled us to infuse 37% more food into gilts during a 28-d lactation, and is an excellent research tool for manipulating nutrition during lactation. Key words: Gilts, lactation, surgery, stomach cannulation, superalimentation
Sex effects on fat hardness meter readings of market weight pigs
Authors: Sather A. P. , Jones S. D. M. , Robertson W. M. , Zawadski Sophie
Published: March 2010

A portable fat hardness meter (FHM) was used to measure the firmness of the inner fat layer on a cross sectional surface over the second thoracic vertebra of pork carcasses. This was a 4-yr study with data collected on 141 barrows, 214 gilts and 270 boars. A statistical model, after adjusting for year and breed of sire (i.e., Lacombe, Landrace, Yorkshire), included sex, linear and quadratic covariates for carcass growth rate (i.e., carcass weight per day of age), a linear covariate for leanness (i.e., carcass fat thickness or dissectible lean) within sex, and a linear by linear covariate of growth rate by leanness, and was used to describe a response surface with fat hardness. No pigs in this study had extremely soft fat (i.e., FHM < 420). However, 4, 2 and 0% of the boars, gilts and barrows had very soft fat (i.e., FHM 420–619). While 10% of the barrows had extremely hard (i.e., FHM > 970) or very hard fat (i.e., FHM 930–970), only 1% of the gilts had very hard fat, and no boars were included in these classes. Relative to the FHM readings of gilts (i.e., 805 ± 6.2), boars (i.e., 780 ± 5.6) had softer fat (P = 0.0002) while barrows (i.e., 835 ± 7.4) had harder fat (P = 0.0001). The majority of boars had slightly soft fat (i.e., FHM 750–829) while gilts and barrows had slightly hard (i.e., FHM 830–889) fat. Regression coefficients for growth rate on fat hardness were homogeneous among the sexes. As growth rate increased fat hardness increased, but was attenuated by a negative quadratic term. Increased leanness was linearly antagonistically related with fat hardness. There were differential effects across sexes (P = 0.0261). As leanness increased, fat became softer among boars and gilts compared with barrows. A linear by linear interaction of growth rate with leanness attenuated this effect. Holding growth rate constant, a 25% reduction of carcass fatness would be expected to reduce fat hardness by 40, 35 and 20 points in boars, gilts, and barrows, respectively. While selection for increased lean growth may result in some degradation in fat quality, the trend towards marketing heavy pigs as they become leaner should be sufficient to offset this effect. Key words: Swine, carcass, grading, growth rate, fat, lean
Evaluation of specific populations of commercial pigs produced in Québec for feed performance, carcass yield and lean meat colour
Authors: Hammell K. L. , Laforest J. P. , Dufour J. J.
Published: March 2010

Data from approximately 850 commercial pigs tested in 12 trials, from 1987 to 1990 at the Beaumont test station in Québec were used to determine the effect of growth rate and body composition on growth performance, carcass yield and lean meat colour. Pigs were housed four to a pen and were fed commercial diets. Feed intake and growth rate were measured during the test, and carcass measurements were taken at slaughter and at 24 or 72 h following slaughter. The different groups of pigs were defined according to a 2 × 2 factorial, with one factor being the growth rate [fast growth (FG) or slow growth (SG)] and the second factor being the body composition of the carcass [fat (F) or lean (L)]. The FG commercial pigs reach market weight at a younger age with lower overall feed consumption and generally a better feed conversion than SG pigs. Furthermore, FG pigs have more backfat, longer carcasses and a slightly darker meat. The L commercial pigs had similar growth performances with a better lean meat yield than the F commercial pigs. Growth variables and composition of the carcass had little effect on the meat characteristics measured. The proportion of barrows compared to gilts was higher in the FG and F groups than in the SG and L groups, which could account for some of the differences observed between groups. However, the rate of growth and the type of body composition affected the growth and feed consumption performances as well as the carcass yield in a similar way for both sexes. Overall, less than 3% and less than 2% of the pigs produced meat with a colour standard of 1 (extremely pale) or 5 (extremely dark), respectively. The SG-L group had a slightly higher proportion of pigs with a pale meat colour compared to the other groups. Key words: Pig, backfat, growth rate, carcass composition, meat colour
Influence of feeding a rapidly rumen degraded dietary protein at night or with a basal mixed ration on performance of dairy cows
Authors: Nia S. A. Moshtaghi , Ingalls J. R. , Robinson P. H. , Gill M. , Kennelly J. J.
Published: March 2010

Twelve multiparous and ten primiparous cows in late lactation were used in a 16-wk study to determine the influence of feeding times of a protein supplement (PS) on dry matter (DM) intake, ruminal fermentation, milk yield and milk composition. One mixed ration consisting of 50% whole crop oat silage, 10% alfalfa silage and 40% grain concentrate was offered twice daily with two-thirds at 08:00 h and the remainder at 18:00 h. In addition, a PS was offered in one meal per day at either 08:30 h or 00:30 h at an amount equal to 12% of the mixed ration DM intake. Half of the cows were assigned to each of the two dietary treatments which were designated as DAY (08:30 h) or NIGHT (00:30 h). Eight cows in the production study, previously fitted with large-diameter rumen cannula, were used to study treatment effects on rumen fermentation and ruminal in situ nutrient disappearance. Rate of passage of PS was measured using chromium-mordanted PS. Time of feeding PS had no effect on DM intake or body weight. Milk yield and milk composition were not influenced by treatment. Treatment had no effect on in situ DM and crude protein disappearance or ruminal rate of passage of PS. Concentrations of all VFA were not influenced by treatments. All measured volatile fatty acid concentrations were higher during the period of 01:00–06:00 h for cows fed the PS at night. Results indicate that timing of feeding a PS can alter ruminal fermentation characteristic without influencing animal performance. Key words: Protein supplement, feeding times, dairy cows, milk yield, rumen fermentation
The effect of formic acid and buffering capacity on the ileal digestibilities of amino acids and bacterial populations and metabolites in the small intestine of weanling pigs fed semipurified fish meal diets
Authors: Gabert V. M. , Sauer W. C. , Schmitz M. , Ahrens F. , Mosenthin R.
Published: March 2010

An experiment was carried out to examine the effects of supplementation of formic acid to semipurified diets containing fish meal for weanling pigs with low and high buffering capacity on nutrient digestion and bacterial populations and metabolites in the small intestine. Twelve barrows, weaned at 21 d, were fitted with a simple T-cannula at the distal ileum. The BW of the pigs at weaning and at the conclusion of the experiment were 7.8 and 13.8 kg, respectively. The pigs were fed four corn starch-based fish meal diets according to a two-period change-over design. The diets were formulated to contain 18% CP. For two of the diets, referred to as NCaP, fish meal was the calcium and phosphorus source. For the remaining two diets, referred to as HCaP, the levels of calcium and phosphorus were doubled (compared with the NCaP diets) by the addition of calcium carbonate and dicalcium phosphate. The diets were supplemented with (+NCaP and +HCaP) or without (−NCaP and −HCaP) 1% (wt/wt) formic acid. The buffering capacity of the HCaP diets increased (P < 0.05) when the levels of calcium and phosphorus were doubled. The pH of the diets were: 6.25, 4.46, 6.13 and 4.59 for the −NCaP, +NCaP, −HCaP and +HCaP diets, respectively. Supplementation of formic acid to diets with low and high buffering capacity did not affect (P > 0.05) the apparent ileal digestibilities of AA. The pH, ammonia and VFA concentrations, bacterial populations in ileal digesta and the incidence of diarrhea were also not affected (P > 0.05). Therefore, the supplementation of 1% (wt/wt) formic acid to corn starch-based fish meal diets with low and high buffering capacity for weanling pigs (7.8–13.8 kg) does not affect nutrient digestibilities and bacterial populations in the small intestine. Key words: Pigs, formic acid, buffering capacity, digestibility, bacteria
Effects of feeding peas to high-producing dairy cows
Authors: Corbett R. R. , Goonewardene L. A. , Okine E. K.
Published: March 2010

The effect of substituting peas for soybean and canola meals as a protein source in a high-producing dairy herd was studied in 66 Holstein cows, divided into two groups based on stage of lactation, parity, level of milk production and days in milk. Two 18.5% crude protein grain concentrate diets were formulated based on the nutrient analyses of the forages available. The control grain mix contained standard protein sources, principally soybean and canola meal (SBM\CM) while the test grain mix was formulated to contain approximately 25% field peas as the major source of protein. Both grain rations were formulated to the same nutrient specifications and balanced for undegradable protein. The duration of the trial was 6 mo during which grain feeding levels were adjusted monthly based on milk yield. For cows in early lactation, 4% fat-corrected milk yield was higher (P < 0.05) for cows fed pea based concentrates (31.3 kg d−1) than for cows fed SBM\CM supplement (29.7 kg d−1). Fat-corrected milk yield was not affected by source of protein in mid- and late-lactation cows. Fat-corrected milk production was not different (P > 0.05) for cows fed SBM\CM compared with cows fed the pea supplement when cows across all stages of lactation were included in the analyses. Milk fat percent was significantly higher (P < 0.05) for early- and mid-lactation cows fed the pea supplement. The results suggest that peas can be substituted for SBM\CM as a protein source for high-producing dairy cows. Key words: Dairy cow, pea, soybean and canola meal supplement, undegradable protein, milk production
Genetic evaluation of lamb performance in Outaouais Arcott and Suffolk sheep, their crosses and Canadian Arcott- or Hampshire-sired three-breed crosses
Authors: Shafto A. M. , Crow G. H. , Parker R. J. , Palmer W. M. , Shrestha J. N. B. , McVetty P. B.
Published: March 2010

A crossbreeding study was used to assess the growth performance of the Outaouais Arcott and Suffolk breeds, their two breed crosses and specific three-breed crosses sired by either Canadian Arcott or Hampshire rams. In a sheep flock maintained under a semi-confinement management system, Suffolk lambs, weighing 3.8 kg at birth, were not significantly heavier than Canadian Arcott- or Hampshire-sired crossbred lambs. Lambs of the Outaouais breed were 26% lighter (P < 0.05) than those of the Suffolk breed, and their two breed crosses had birth weights between the two parental purebreds. The relative ranks among the breeds and their crosses had not changed by 42 d of age with lamb weights ranging from 10.6 to 12.6 kg. By 120 d of age the Canadian Arcott- and Hampshire-sired lambs weighed approximately 28–29 kg and were not significantly different in weight from the Outaouais and Suffolk breeds and their two breed crosses. Additive and maternal genetic effects m the Suffolk breed were significantly greater than in the Outaouais breed for birth weight by 12.9 and 12.6% respectively. By 42 d, no difference was detected between breeds for direct genetic effect. However, the maternal effect favoured the Suffolk breed by 15.8% (P < 0.05). By 120 d, the direct genetic effect was significantly greater in the Outaouais breed by 9.8%, but maternal genetic effects continued to favour the Suffolk breed by 12.5% (P < 0.05). Heterosis effects were generally small (< 3.1%) and not significant for lamb weights. The terminal sire breeds showed no significant difference between Canadian- and Hampshire-sired lamb weights. Generally, results obtained for two analyses (least squares model and multi-trait animal model) of the same data set were consistent. However, the animal model would be preferable when estimating parameters and breeding values from an unbalanced data set with unequal subclass frequencies. Key words: Lambs, weight, genetic effects, heterosis, animal model
The prediction of saleable meat yield in lamb carcasses
Authors: Jones S. D. M. , Robertson W. M. , Price M. A. , Coupland T.
Published: March 2010

A total of 281 lamb carcasses covering three weight groups (18–22.9, 23–25.9 and 26–30 kg) and fatness (< 3 mm, 3–5 mm and > 5 mm) were used to determine the usefulness of several carcass measurements for predicting saleable meat yield. Carcasses were measured for fat and muscle depth, 3–4 cm from the mid-line between the 10th and 11th ribs, 12th and 13th ribs and immediately adjacent to the 13th rib using a Hennessey Grading Probe. This technique also determined total tissue depth at 11 cm from the mid-line between the 10th and 11th and 12th and 13th ribs. The depth of tissues over the 12th rib 11 cm from the mid-line was measured with a ruler. Carcasses were also visually assessed for muscle development (conformation score) on a 5-point scale (1 = thinly fleshed; 5 = thickly fleshed). All carcasses were fabricated into primal cuts which were trimmed to 5 mm of fat and deboned to provide an estimate of saleable meat yield. Ewe lamb carcasses had a higher proportion of kidney fat than wethers in all weight and fat groups (which ranged from 2.6 to 17.9 g kg−1 carcass weight). Saleable meat yield decreased as carcasses became fatter, whereas weight group had little influence on saleable meat yield within a fat group. Ewe lamb carcasses had lower saleable meat yields than wether lamb carcasses, mainly because of their higher amounts of kidney fat. A ruler measurement of tissue depth over the 12th rib combined with carcass conformation score provided the most precise prediction (R2 = 0 61; RSD 17.1) of saleable meat yield. It was concluded that a simple manual system based on these two measurements provided an adequate prediction of saleable meat yield. The accuracy of the procedure would be increased by excluding kidney fat from carcass weight for the prediction of saleable meat yield. Key words: Lamb, carcass, composition, probe, fat, grade
Association of class I bovine lymphocyte antigens with profitability and lifetime yields in the Holstein breed
Authors: Batra T. R. , Macdonald P. A. , Stear M. J.
Published: March 2010

Ninety-four Holstein cows from the Agriculture and Agri-Food Canada herd at Ottawa were serologically typed for the BoLA-A locus. Of the 37 serologically defined specificities, only 10 were present in Holstein cows. A gene substitution model, which included the effect of BoLA alleles and the breeding value of the sire as a covariant, was used to evaluate the association between these genes and lifetime yields and profitability. Allele A14 was significantly (P < 0.05) associated with increased lifetime milk, protein and lactose yields as well as greater milk value and annualized discounted net returns. Therefore, the potential may exist for increasing the lifetime yields and profitability in dairy cattle using genes of the BoLA-A locus. Key words: BoLA, lifetime yields, profitability, Holstein
The relationships between the concentrations of individual amino acids and protein in wheat and barley grain grown at selected locations throughout Manitoba
Authors: Boila R. J. , Stothers S. C. , Campbell L. D.
Published: March 2010

The concentrations of protein and individual amino acids were determined in the grain from three cultivars of wheat and three cultivars of barley, each grown at 12 locations throughout Manitoba over 3 consecutive years. Protein concentration differed (P < 0.05) among the cultivars of wheat but not (P > 0.05) among cultivars of barley. Although the concentrations of several amino acids differed (P < 0.05) among cultivars of wheat or barley the differences among cultivars of each grain were not considered to be critical in relation to the requirements for indispensable amino acids for swine or poultry. The percentage of an ammo acid in the DM of wheat and barley increased (P < 0.05) linearly with an increase in percentage of protein in the grain. The wide range of r2 (0.29 to 0.88) obtained for this amino acid-protein relationship may be due to the different effect of environment (location and year of growth) on the concentration of individual amino acids, compared to protein, among cultivars of wheat or barley. The percentage of total variance due to an interaction between cultivar and environment was low for protein but was several fold higher for individual amino acids. The error in the prediction of amino acid concentrations with regression equations may be no different than the error associated with predicting the mean concentrations of amino acids in the protein of wheat or barley as g (100 g protein)−1, and obtained from tabulations of analyses. However, regression equations for lysine in wheat and barley did account for the significant (P < 0.05) decrease in concentration of lysine in the protein as the percentage of protein in these grains increased. Key words: Grain, wheat, barley, protein, amino acids, Manitoba
Laying hens do not have a preference for high-frequency versus low-frequency compact fluorescent light sources
Authors: Widowski T. M. , Duncan I.J.H.
Published: March 2010

To determine whether hens find the flicker of some fluorescent light aversive, the preferences of 16 light hybrid laying hens for light produced by high-frequency or low-frequency compact fluorescent lamps were tested individually in a two-room testing chamber in which each room could be illuminated by either source. The spectral distributions of the lamps and levels of illumination (ca. 14 lx) in the two rooms were carefully matched and both rooms contained feed, water, and a nesting area. Overhead video cameras recorded the position and behaviour of the birds during a 6-h test period on each of 2 d. The light sources in the rooms were switched on the second test day to balance for any preferences for chamber room.On both test days, the birds spent similar amounts of time in fluorescent light produced by high-frequency and low-frequency lamps (P > 0.10). When data from both test days were combined, the birds spent on average 48.2% of time in light from high-frequency lamps and 51.8% from low-frequency. The frequency distributions of individual activities indicated that the birds performed all activities in light produced by both types of lamps. The results indicate that the laying hens in this experiment did not exhibit a preference for high-frequency fluorescent lamps over low-frequency lamps. We conclude that at the illumination levels used in this experiment, the hens did not perceive the flicker of low-frequency light or they perceived it but did not find it aversive. Low-frequency fluorescent light does not appear to adversely affect the welfare of hens. Key words: Lighting, fluorescent, flicker, behaviour, poultry
Glucose, alpha-amino nitrogen, and amino acid exchange across the hindlimb in young double-muscled type bulls maintained at two growth rates
Authors: Hornick J. L. , Eenaeme C. Van , Gauthier S. , Baldwin P. , Istasse L.
Published: March 2010

The effect of growth rate and protein supplementation on muscle metabolism of eight bulls from the Belgian Blue breed, double-muscled type, was investigated by the arterio-venous difference technique. A low growth (LG) group was maintained at a low growth rate over 36 d, and a rapid growth (RG) group for 28 d before receiving a fattening diet allowing for a rapid growth. At the end of the RG period the RG bulls received a supplement of protected soybean meal. Animals were fitted with an aortic ultrasonic blood flow probe and with catheters in the aorta and the vena cava. The blood flow in the hindlimbs of bulls varied greatly by time of the day but was higher in the RG group. The RG group had a higher arterio-venous difference (AVD) and uptake of alpha-amino nitrogen while AVD in essential amino acids was four times higher and uptake eight times higher. Significant higher AVD or uptake was observed in individual amino acids such as leucine, isoleucine and lysine. The supplementation with protected soybean meal had significant negative effect on the uptake of several amino acids. It was concluded that caution should be exercised when measuring punctually blood flow in muscle tissue, for example by dilution techniques. At high growth rate, the requirements for amino acids are larger than for glucose. Excess protein provides no additional benefit. Key words: Bull, hindlimb catheterism, growth rate, protected soy bean, metabolite
Evaluation of linseed meal for dairy cows: Interaction with grain source on forestomach and whole-tract digestion
Authors: Robinson P. H. , Khorasani G. R. , Kennelly J. J.
Published: March 2010

Four Holstein cows in midlactation were fed one of four totally mixed rations differing in grain source (ground barley or cracked corn) and protein meal (solvent-extracted linseed meal or canola meal) in a 12-wk 4 × 4 Latin square experiment. Diets were 10% second-cut alfalfa silage, 50% whole crop oat silage and 40% mixed concentrate on a DM basis. Intake of DM, OM, NDF, starch and crude protein were not influenced by grain source or protein source within grain. Forestomach and whole-tract digestion of these same components were not influenced by treatments, except forestomach digestion of starch which was higher on barley versus corn based diets. Rumen pool sizes of total ingesta DM OM, and NDF were not influenced by treatment, although the rumen pool of NDF tended (P = 0.10) to be higher on barley-based diets. The rumen NAN pool was higher on barley-based diets and this primarily reflected a numerically higher bacterial N pool. Duodenal flow of NAN, bacterial N, residual N and AA protein were also unaffected by treatment although the AA profile of duodenal protein was influenced by both grain source in the diet and source of protein within grain source. Based upon all these results, solvent extracted linseed and canola meals appear to be broadly equivalent as high DIP sources for dairy cows. In addition, animal protein status calculations suggest that the performance of the cows was limited by supplies of DIP on all diets indicating that linseed and canola meals were truly equal as high DIP protein sources for dairy cows. Key words: Canola meal, linseed meal, amino acid, duodenum
Impact of gastric pH on dietary enzyme activity and survivability in swine fed β-glucanase supplemented diets
Authors: Baas T. C. , Thacker P. A.
Published: March 2010

A series of experiments was conducted to determine the effect of pH on β-glucanase activity and to monitor the effect of passage through the stomach on the ability of enzymes to degrade β-glucans. In exp. 1, β-glucanase activity was determined in 10 commercially available enzyme products at 5 pH levels (2.5, 3.5, 4.5, 5.5 and 6.5) using a discontinuous assay. Little activity was evident at pH 2.5, and activity was only slightly increased at pH 3.5. The highest activity occurred at pH 4.5 and 5.5. Enzyme activity declined quickly at pH 6.5. Experiment 2 evaluated the capability of β-glucanase to recover activity after incubation at suboptimal pH levels. Five enzyme preparations were incubated at three pH levels (2.5, 3.5 and 4.5) for 15, 30, 60 or 120-min. The pH level was then increased to pH 5.5, which was the optimum pH for activity determined in exp. 1. All enzyme products were relatively stable at pH 4.5 and 5.5. Enzyme products treated at pH 3.5 started to lose activity and all enzyme products exhibited a deterioration effect when incubated at pH 2.5. However, all enzymes recovered some activity upon return to pH 5.5. Experiment 3 was designed to evaluate the amount of β-glucanase activity leaving the stomach of the pig. Six barrows cannulated with a simple T-cannulae located at the start of the duodenum were used in a 6 × 6 Latin square design experiment. The diets consisted of a control and five diets supplemented with the same enzymes used in exp. 2. The level of β-glucanase activity in the digesta from pigs fed any of the diets decreased over time as pH decreased. However, across all products, 52 and 26% of initial activity could still be detected 60 and 240 min after feeding. Experiment 4 was conducted to evaluate the effectiveness of the five enzyme sources in improving the performance of pigs fed hulless barley-based diets. Supplementation of hog growing-finishing rations with any of the enzyme products failed to significantly (P > 0.05) improve daily gain, feed intake or feed efficiency. The digestibility coefficients for dry matter, crude protein and energy showed a general trend towards improved digestibility with enzyme supplementation (P > 0.05) with Biofeed producing a significant increase. The overall results of these experiments indicate that although the low pH found in the stomach of the pig is detrimental to enzyme activity, some enzyme activity is retained in the small intestine of the pig. Therefore, the low gastric pH of the pig and its effects on enzyme activity cannot completely explain the lack of response of pigs to β-glucanase. Key words: β-glucanase, pH, pig, enzyme
Measuring leucine flux and protein metabolism with carbon-13 isotope in growing cattle
Authors: Lapierre H. , Pelletier G. , Ouellet D. R. , Lobley G. E. , Bernier J. F.
Published: March 2010

Leucine irreversible loss (ILR) and fractional leucine oxidation (FO) were estimated using primed infusions of L-[1-13C]leucine and [13C]bicarbonate. Feed restriction decreased (P < 0.05) ILR from 16.42 to 10.82 mmol h−1, but did not affect FO (0.172) in two young dairy heifers. In six growing steers, ILR and FO averaged 30.03 ± 5.09 mmol h−1 and 0.147 ± 0.027, respectively. L-[1-13C]leucine and [13C]bicarbonate can be successfully used to measure the different components of protein metabolism in cattle. Key words: Stable isotope, protein metabolism, leucine, bicarbonate, cattle
Prediction of lean yield in yearling bulls using real-time ultrasound
Authors: Bergen R. D. , McKinnon J. J. , Christensen D. A. , Kohle N.
Published: March 2010

A study was undertaken to determine the repeatability and accuracy of ultrasound measurements taken on yearling bulls and to assess the value of these live measurements to predict lean yield. Ultrasonic fat depth and 1. dorsi area were measured on 616 yearling bulls prior to slaughter. Corresponding carcass measurements were obtained through the Agriculture Canada Blue Tag Program. Carcass side lean (LEANYIELD) was extrapolated from the lean content of the seven-bone rib section from the carcasses of 41 Angus and 41 Charolais bulls. Stepwise multiple regression used live (USFAT and USREA) measurements to predict LEANYIELD. Repeatability (SER) and accuracy (SEP) statistics for USFAT were 0.8 mm and 1.6 mm, respectively. The corresponding results for USREA were SER = 4.3 cm2 and SEP = 7.8 cm2. The ultrasound lean yield (USLEAN) prediction equation was: USLEAN = 599.2 − (9.5 × USFAT) + (1.1 × USREA); R2 = 0.73, RSD = 17.9 g kg−1. Results indicated that LEANYIELD was predicted better by USLEAN (SEP = 18.0 g kg−1) than by BTLEAN (SEP = 22.6 g kg−1). Results from a second group of dissected bulls (n = 110) confirmed that ultrasound can predict LEANYIELD as effectively as carcass measurements (SEP = 22.8 and 22.6 g kg−1 for USLEAN AND BTLEAN) in young breeding bulls in this study. Key words: real-time ultrasound, performance testing, beef bulls, carcass traits
Recombinant bovine somatotropin increases nutrient absorption by the proximal small intestine in sheep
Authors: Bird A. R. , Croom Jr. W. J. , Fan Y. K. , Daniel L R. , McBride B. W. , Taylor I. L.
Published: March 2010

Dorset crossbred ewes were used to determine the effect of recombinant methionyl bovine somatotropin (bST) on small intestinal nutrient absorption. Ewes were kept indoors in individual pens and allowed free access to a concentrate diet (18% CP). (150 μg kg−1) or saline were subcutaneously injected once daily for 10 d. An in vitro assay system was used to estimate the rate of accumulation of 3H-3-O-methylglucose and 14C-proline by small intestinal segments. Feed intake and liveweight gain were similar in ewes administered bST or saline. At the end of the treatment period, plasma ST, IGF-I and glucose concentrations were significantly higher in ewes treated with bST. In the duodenum, active and total glucose absorption were greater (P < 0.05) in bST treated ewes. There was also a tendency for bST treatment to increase duodenal total proline absorption (P < 0.10). Glucose and proline absorption in the jejunum and ileum were not significantly affected by bST. Jejunal ouabain-sensitive and ouabain-insensitive oxygen consumption was similar in ewes administered saline or bST. Water, DNA and protein content of small intestinal mucosa were unaffected by bST administration. These results indicate that bST upregulates glucose transport in the duodenum of sheep. Key words: Intestine, nutrient absorption, somatotropin, IGF-I, sheep
In situ degradabilities of forages selected and not selected by grazing cattle
Authors: Okine E. K. , Caskey B. , Corbett R. , Berg B. , Goonewardene L. A.
Published: March 2010

The degradation properties of forages may affect the selective grazing behaviour of cattle. Differences in ruminal degradation characteristics were observed between samples of a 50:50 alfalfa:bromegrass mixture which were sampled from selected and not selected portions of the same pasture by grazing cattle. Fraction A and rate of degradation of fraction B were higher for forages from selected than from non-selected portions of the pasture. Key words: Cattle, forage, grazing, selection, degradation
Effects of dietary protein level on growth and body composition in mice divergently selected for fat content
Authors: Bertram M. J. , Schoenherr W. D. , Eisen E. J. , Coffey M. T.
Published: March 2010

A study was conducted to examine the effects of dietary protein percentage and selection for divergence in fat content on growth and body composition in mice. The three lines used had been selected as follows: high epididymal fat pad weight as a percentage of body weight (HF), low epididymal fat pad weight as a percentage of body weight (LF) and a randomly selected control (RC). Mice from each line were allotted at weaning (3 wk of age) to one of four dietary protein percentages: 12, 16, 20, and 24%. Growth and efficiency of feed conversion were measured at 2-wk intervals and mice were killed and body composition was measured at 9-wk of age. Overall, HF mice grew faster were more efficient at converting feed to body weight gain, and had empty carcasses with a higher percentage of tat (P < 0.05) and a lower percentage of protein than LF mice. However, fat-free empty-body protein and ash percentages, protein gain, protein gain:protein intake, and protein gain:energy intake ratios were not different among genotypes. As dietary protein percentage increased, gain:feed ratio increased quadratically (P < 0.05) in all genotypes and was maximized m mice consuming 16% protein. Protein gain was maximized in mice consuming 16% protein. Feeding diets providing protein percentages above or below 16% depressed protein gain and protein gain:energy intake ratio. Genetic line-by-dietary-protein-level interactions were generally not significant for growth, feed efficiency and body composition traits. Key words: Mice, dietary protein, growth, body composition, fat deposition
Can photoinhibition control phytoplankton abundance in deeply mixed water columns of the Southern Ocean?
Authors: Alderkamp Anne-Carlijn , de Baar Hein J. W. , Visser Ronald J. W. , Arrigo Kevin R.
Published: March 2010

To study how natural Southern Ocean phytoplankton communities acclimate to rapid fluctuations in irradiance levels that result from deep wind‐driven mixing of the upper water column, we measured their fluorescence properties (Fv:Fm, maximum quantum yield of photosystem II; and qN, non‐photochemical quenching) and pigment composition. Values of Fv:Fm were low (> 0.46) and qN was high (< 0.67) throughout the upper mixed layer (UML). Short‐term (20‐min) exposure to incident surface irradiance strongly reduced Fv:Fm and recovery was slow under subsequent incubation at low irradiance. This suggests that phytoplankton cells are frequently photodamaged when mixed up to the surface from depth. Recovery of Fv:Fm was suppressed when lincomycin was added, inhibiting synthesis of the photosystem II reaction center D1 protein. This indicates that D1 protein repair is crucial in maintaining photosynthetic performance under fluctuating irradiance levels. Regions within the Antarctic Circumpolar Current (ACC) with a deep UML had lower depth‐integrated phytoplankton biomass than regions close to the Antarctic continent with a shallow UML. Surprisingly, the depth‐averaged light level within the UML in these latter regions was lower than in the ACC. Thus, it appears that photodamage incurred during the high irradiance portion of the vertical mixing cycle, rather than light limitation, controls phytoplankton growth in regions of the Southern Ocean with a deep UML. This concept represents a shift from the widely accepted paradigm that phytoplankton growth in the open Southern Ocean is limited by low levels of light or inadequate iron supply.
The Memory-History-Popular Culture Nexus: Pearl Harbor as a Case Study in Consumer-Driven Collective Memory
Authors: Leavy Patricia
Published: March 2010

In this paper I examine the fusing of collective memory, history and popular culture by analyzing current trends in American-made commercial films with historical events as subject matter that have also been distributed to a global audience. Pearl Harbor is the primary case study. Analysis shows that dominant historical narratives are reified by the use of what I term an ‘anticipatory-driven’ film experience where audience members engage in an interaction with pre-existing mainstream collective memory while their anticipation for impending climactic trauma is systematically heightened. Comparisons are made to other widely released US films about national and international events and ‘non-events.’ Questions are also raised about the increasing global importance of the memory-history-popular culture nexus post 9-11, and, how US produced films about 9-11 may or may not engage in the practices detailed in this analysis. In this vein the paper concludes with a discussion of how Pearl Harbor was marketed, edited and received in Japan, the second largest audience for Hollywood films and what this implies about social memory construction in a global commercial context.
Putting it into Practice: Using Feminist Fractured Foundationalism in Researching Children in the Concentration Camps of the South African War
Authors: Stanley Liz , Wise Sue
Published: March 2010

Feminist fractured foundationalism has been developed over a series of collaborative writings as a combined epistemology and methodology, although it has mainly been discussed in epistemological terms. It was operationalised as a methodology in a joint research project in South Africa concerned with investigating two important ways that the experiences of children in the South African War 1899-1902, in particular in the concentration camps established during its commando and ‘scorched earth’ phase, were represented contemporaneously: in the official records, and in photography. The details of the research and writing process involved are provided around discussion of the nine strategies that compose feminist fractured foundationalism and its strengths and limitations in methodological terms are reviewed.
Towards a Sociology of Endings
Authors: Crow Graham
Published: March 2010

Sociological commentaries on the future are frequently built around the claim that we are witnessing the beginning of a new social phenomenon as a result of an existing one coming to an end. Recent examples of discussions framed in terms of new beginnings include reference to the emergence of new forms of family, community, politics, slavery and the international division of labour, while the focus on endings includes analyses of the end of marriage, masculinity, work, class, capitalism, development, history, and the world as we know it. This paper argues that such claims exaggerate the discontinuous nature of social change, and that a more nuanced account of the processes involved in beginnings and endings needs to be developed. As a contribution to this project, ten propositions are advanced about the processes whereby old social phenomena come to an end and new ones emerge. For example, people's perceptions about whether they stand to gain or lose from the substitution of a new social arrangement for an old one are volatile, and this has major implications for the prediction of their behaviour. Taken together, the ten propositions offer a distinctive perspective on the understanding of long-term social change.
Too Close for Comfort? ‘Race'and the Management of Proximity, Guilt and Other Anxieties in Paid Domestic Labour
Authors: Bott Esther
Published: March 2010

This paper examines relations between migrant domestic workers and their employers in London, and how employers use ideas about ‘race’ and racial difference to manage the difficulties and tensions involved in sharing their houses with employees. Using findings from preliminary interviews with employers (the initial phase of data gathering in a wider ongoing project), it looks at how employers might structure proximity/distance relations; levels of intimacy; social hierarchy and guilt management around a conceptual framework that hinges on notions of ‘difference’ and Otherness.