bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of feeding textured concentrates with alfalfa cubes to lactating dairy cows producing low fat milk
Authors: Gardner W. C. , Keyserlingk M. A. G. von , Shelford J. A. , Fisher L. J.
Published: March 2010

Twenty–one multiparous Holsteins were used in a cross over design with two 28-d periods. Cows were randomly assigned to two treatments to assess the effect of textured and pelleted concentrates fed with alfalfa cubes on feed intake, milk yield, milk composition and rumen volatile fatty acid concentrations. Those animals receiving the textured concentrate had significantly (P < 0.05) higher milk yield and milk fat percentage than did those animals fed the pelleted concentrate. A significant difference in the ratio of milk protein to milk fat was also observed with the cows receiving the pelleted concentrate having a ratio of 1.31 and the cows receiving the textured concentrate a ratio of 1.02. No significant (P < 0.05) differences were observed between the textured and pelleted feeds in total or individual volatile fatty acid concentrations. These results indicate that the feeding of textured concentrates can lead to an increase in milk fat production when compared with the feeding of pelleted concentrates. Key words: Dairy cattle, milk composition, textured and pelleted concentrate, VFA
Effect of microbial enzyme supplementation on energy, amino acid digestibility and performance of pigs fed hulless barley based diets
Authors: Baidoo S. K. , Liu Y. G. , Yungblut D.
Published: March 2010

Two experiments were conducted to investigate the influence of a microbial enzyme preparation on the digestibility and performance of starter-growing pigs fed hulless barley based diets. In the digestibility trial, eight pigs with an average initial body weight of 14.3 ± 0.4 kg initial liveweight were surgically fitted with steered ileo-cecal valve cannulas at the terminal ileum. Two hulless barley varieties (Condor and CDC Buck) were separately used as the dietary energy source (77.6%) with canola meal as the protein supplement (20%). Enzyme supplementation improved (P < 0.05) the ileal dry matter (DM) digestibility by 15.2%, gross energy (GE) by 11.0% and protein by 7.6%. The average apparent ileal digestibility of the indispensable amino acids was improved by 6.9% (P < 0.05), and of nonstarch polysaccharides (NSP) was improved by 90%. The total-tract digestibility of DM was increased by 6.2%, GE by 6% and crude protein (CP) by 9.4% (P < 0.05). Enzyme supplementation tended to enhance digestion in the small intestine instead of the hind-gut as expected. In the growth performance trial, positive responses from enzyme supplementation were observed from both mash and pelleted diets fed to 48 pigs grown from 9 to 60 kg liveweight. The ADG was improved by 8.6% (P < 0.05) and feed conversion by 8.7% (P = 0.09). Pelleting had no adverse effect on enzyme activity. The results demonstrated that the enzyme supplementation improved (P < 0.5) nutrient utilization and performance of pigs fed diets containing hulless barley. Key words: Enzyme, hulless barley, digestibility, performance, swine
Effects of isoenergetic barley grain and alfalfa pellet diets on in vitro lipogenesis and lipogenic enzyme activities in subcutaneous adipose tissue from sheep
Authors: Okine E. K. , Arthur P. F.
Published: March 2010

The effects of feeding isoenergetic barley grain or alfalfa pellets on in vitro lipogenesis, palmitate esterification, and lipogenic enzymes activities in biopsy samples of subcutaneous adipose tissue in 10 ewes were studied. Acetyl CoA carboxylase and FAS activities and rate of esterification were 52, 38, and 88%, respectively, higher (P < 0.05) in subcutaneous adipose of ewes fed the concentrate versus those fed the roughage diet. Key words: Isoenergetic, adipose tissue, acetyl CoA carboxylase
Evaluation of wheat-based wet distillers' grains for feedlot cattle
Authors: Ojowi M. , McKinnon J. J. , Mustafa A. , Christensen D. A.
Published: March 2010

This study was conducted to determine the nutritive value of wheat-based wet distillers' grains (WDG) for ruminants. Chemical composition and in situ rumen degradability characteristics of WDG were compared with wet brewers' grain (WBG). The in situ trial involved three 48 h incubations utilizing one ruminally fistulated cow. Trail 2 compared the value of WDG in growing and finishing rations relative to WBG and a control based on standard feed ingredients. Relative to WBG, WDG had greater (P < 0.05) NDF and ADL and similar ADF and CP levels. Fractionation of CP indicated that WDG contained more (P < 0.05) neutral detergent and less acid detergent insoluble CP than WBG. Effective degradability of DM, CP, NDF and ADF in WDG exceeded (P < 0.05) WBG. Animal performance in the growing period was similar (P > 0.01) among treatments. During the finishing period the control fed steers grew faster (P < 0.05) than WBG fed steers. WDG fed steers exhibited more (P < 0.05) intermuscular fat than control or WBG fed steers and less (P < 0.05) subcutaneous fat than WBG fed steers. It was concluded that WDG is more degradable than WBG and thus cannot be considered as good a source of rumen undegraded protein. WDG can be used effectively as an energy and protein source for growing and finishing cattle. Key words: distillers' grains (wet), brewers' grains (wet), rumen degradability, cattle, gain, carcass
Teat seeking success of newborn piglets after drying or warming
Authors: Christison G. I. , Wenger I. I. , Follensbee M. E.
Published: March 2010

At birth, 98 piglets were either completely dried with paper towels, or moved under a heat lamp, or left untouched. The three treatments were randomly assigned, within birth order trios, to 11 litters of pigs. Sixty percent of all piglets contacted the udder within 10 min and 91% had nursed within 70 min. Treatment or birth order did not affect the mean time from birth to first udder contact (20 min; SEM 3.5) or the mean time from birth to first suckle (40 min; SEM 4.8). Average daily gain to 24 h or 21 d was not significantly affected by treatment. Mortality to 3 d was 6% for the towel-dried group, 0% for the pigs placed under the heat lamp and 21% for the untouched group. We conclude that drying or warming at birth did not affect suckling success of active piglets, but there was an indication that survival was improved. Key words Newborn, piglet, drying, warming, suckling, survival
Comparison of hot-iron and freeze branding on cortisol levels and pain sensitivity in beef cattle
Authors: Schwartzkopf-Genswein K. S. , Stookey J. M. , Passillé A. M. de , Rushen J.
Published: March 2010

Thirty yearling (450–500 kg) heifers of mixed breeds (Hereford, Charolais, Angus and Shorthorn) were habituated to handling over a 14 ± 2 d period before branding and were fitted non-surgically with jugular catheters 1 before branding. On the day of branding, heifers were assigned to hot-iron brand (H), freeze brand (F), or control (C) treatments according to a predetermined randomized branding order (n = 10 per treatment). Blood samples were obtained at 20 and 0 min before and 20, 40, 60, 80, 100, 120, 140, 160 and 180 min after application of branding treatments. To detect stress-induced analgesia, each animal's sensitivity to pain was assessed by measuring the time it took them to respond to a thermal energy source (laser) applied to their hind legs. Foot-lift latencies were obtained 0, 10, 20, 60 and 120 min after the treatments were imposed. Sensitivity to touch also was assessed 1 and 7 d after branding by placing pressure on the brand site and measuring the amount of movement by the animals. Both H and F heifers had higher mean plasma cortisol concentrations than C animals 20 and 40 min after branding (P < 0.05). However, hot branding was found to cause a more pronounced cortisol response than freeze branding at 40 min (P < 0.05). No treatment differences in foot-lift latencies or sensitivity to touch were observed. Both branding methods cause discomfort in cattle; however, hot branding appears to cause a greater acute response than freeze branding. Key words: Branding, cattle, cortisol, stress-induced analgesia
Culling in Quebec Holstein herds. 2. Study of phenotypic trends in reasons for disposal
Authors: Dürr J. W. , Monardes H. G. , Cue R. I. , Philpot J. C.
Published: March 2010

A total of 1 558 080 lactation records from PATLQ Holstein cows were used to describe the annual trends in reasons for disposal in Quebec dairy herds from 1981 to 1994. Differences in culling trends between official and owner sampler herds, between parities, and between Quebec agricultural regions were compared. Statistical analysis was carried out by means of a logistic regression model, and the significance of trends was tested by linear contrasts. Involuntary culling had a clearly ascending trend during the period of study (from 23% in 1981 to 32% in 1994), as opposed to culling for low production (voluntary), which had a descending trend (from 16% in 1981 to 4.5% in 1994). This increase in involuntary culling was mainly due to increasing trends in culling for reproductive problems, mastitis and feet and leg problems. Official herds had a greater proportion of cows with sale codes and fewer cows culled for mastitis than owner sampler herds, and the trend for sale codes was ascending for official and stable for owner sampler herds. Culling for low production was more intensive in first parity, but all parities showed a descending trend over time. The proportion of cows with sale codes decreased with parity number. For all involuntary reasons, proportion of cows culled increased with parity number. Key words: Reasons for disposal, Holstein, Quebec, culling
Effect of trenbolene acetate/estradiol implants and estrus suppression on growth performance and carcass characteristics of beef heifers
Authors: Popp J. D. , McAllister T. A. , Burgevitz W. J. , Kemp R. A. , Kastelic J. P. , Cheng K.-J.
Published: March 2010

The effects of estrus suppression (none, oral melengestrol acetate (0.4 mg d−1) or ovariectomy via Willis spay technique) and an anabolic implant (none or Synovex Plus®) on growth performance and carcass characteristics were determined using 90 beef heifers of composite breeding in a 2 × 3 factorial experiment conducted in the last 50 d before slaughter. Spaying caused no morbidity or mortality and resulted in average daily gains (1.37 kg d−1) comparable to heifers fed melengestrol acetate (1.33 kg d−1). Implanting improved (P < 0.05) feed efficiency and increased (P < 0.05) animal gain, ribeye area, carcass weight and yield and reduced (P < 0.05) intramuscular fat deposition but estrus suppression did not. Method of estrus suppression did not influence (P > 0.05) carcass traits. Spaying and implanting represent an effective means of improving returns from heifers, even late in the finishing period. Key words: Ovariectomy, implants, beef heifers, carcass composition
Mammary gland development of sows injected with growth hormone-releasing factor during gestation and(or) lactation
Authors: Farmer C. , Pelletier G. , Brazeau P. , Petitclerc D.
Published: March 2010

Twenty-four gilts received s.c. injections of saline or growth hormone-releasing factor (GRF) in late gestation and(or) lactation. Sows were sacrificed on day 30 of lactation and functional mammary glands were excised for chemical analyses. Weight of parenchymal (P = 0.004) and extra-parenchymal tissues (P = 0.002) were decreased with GRF injections during lactation. Parenchymal mass per milligram of DNA also decreased (P = 0.025) with GRF in lactation while parenchymal DNA concentration increased (P = 0.03). Exogenous GRF given to sows during lactation therefore decreased total parenchymal mass, increased cell density and decreased mammary cell size. Key words: Sow, mammary gland, growth hormone-releasing factor
The effect of pectinase and α-galactosidase supplementation on the nutritive value of peas for broiler chickens
Authors: Igbasan F. A. , Guenter W. , Slominski B. A.
Published: March 2010

A total of 192 3-d-old male broiler chickens (Arbor Acres) were randomly assigned to six dietary treatments with eight replicates of four birds each per treatment. The treatments consisted of five levels (0, 50, 75, 100 and 125 U kg−1) of pectinase enzyme and a combination of pectinase (50 U kg−1) and α-galactosidase (6250 U kg−1) enzymes. The performance trial lasted for 2 wk. At the end of 2 wk, excreta were collected on three diets to determine nitrogen-corrected apparent metabolizable energy (AMEn). Growth rate, feed intake and feed conversion of birds fed pea diets supplemented with graded levels of pectinase enzyme were not different from their counterparts fed a diet without pectinase supplementation; however, growth rate tended to be improved (P = 0.11). Also, the AMEn values of these diets were not affected. Compared with the control diet, addition of a combination of pectinase and α-galactosidase tended to improve growth rate (P = 0.06). Key words: Peas, pectinase, α -galactosidase, broiler chicken
Evaluation of seal meal as a protein supplement for growing steers
Authors: Charmley E. , O'Reilly E.
Published: March 2010

This experiment evaluated the suitability of dried seal meal (SM) as a protein supplement for growing steers. Protein in the SM had an effective degradability of 65% and a slow degradation rate in the rumen. There was a positive quadratic growth response to replacing soybean meal (SBM) with SM (P < 0.05). We attribute this response to optimized concentrations of fat and metabolizable protein supplied by the SM/SBM mixtures. We conclude that SM is a beneficial protein source for growing steers when combined with SBM. Key words: Growing steer, seal, protein supplement, silage
Economic values for beef production traits from a herd level bioeconomic model
Authors: Koots K. R. , Gibson J. P.
Published: March 2010

A bioeconomic model of an integrated Canadian beef production system was developed to derive economic values for genetic improvement of multiple traits. The breeding objective was assumed to be profit maximization of the integrated enterprise. Sixteen input traits were identified as potentially influencing returns and costs in the system. These were mature size, direct and maternal calving ease (in heifers and cows separately), cow fertility, calf survival, cow survival, peak milk yield, residual post-weaning growth rate, residual feed intake in growing animals, residual feed intake in mature animals, residual slaughter weight and dressing percentage at constant backfat thickness, marbling and lean percentage. Most traits were defined to be functionally independent of each other. Thus, traits related to mature size were redefined as residual traits after accounting for the nonlinear relationships among mature size, growth and feed intake traits following mammalian size scaling rules. The base model, which incorporates average returns and costs under production and marketing systems typical of eastern Canada, is described. Economic values in the base model suggest that calf survival, fertility, residual feed intake, and dressing percentage are of primary economic importance in a purebreeding system. These traits also ranked highly in dam lines and (with the exception of fertility) in sire lines in terminal crossbreeding systems. Key words: Beef cattle, economic values, bioeconomic model
Effects of fibrolytic enzymes in corn or barley diets on performance and carcass characteristics of feedlot cattle
Authors: Beauchemin K. A. , Jones S. D. M. , Rode L. M. , Sewalt V. J. H.
Published: March 2010

A study was conducted to establish whether fibrolytic enzyme feed additives influence performance of feedlot cattle fed high grain diets, and to compare the effects of feeding diets of barley or corn on performance and carcass characteristics. Crossbred beef steers (408 kg) were offered high concentrate diets (95.1%, dry matter basis), consisting mainly of barley and barley silage or corn and corn silage. Concentrates were treated with either no enzyme or one of two enzyme mixtures. Calves were slaughtered after a 103- to 145-d feeding period at an average weight of 570 kg and 10.8 mm of backfat. Barley-fed calves grew faster (1.45 vs. 1.29 kg d−1), ate more dry matter (DM; 9.79 vs. 9.31 kg d−1), and converted DM to gain (6.85 vs. 7.35 kg DM kg−1gain) more efficiently compared with corn-fed calves (P < 0.001). Meat from barley-fed calves tended to be more highly marbled and was brighter in colour than meat from corn-fed calves, but diet had no effect on muscle score, rib eye area, or carcass leanness. Effect of enzymes differed for corn and barley diets; Enzyme 1, a preparation with higher xylanase activity than Enzyme 2, improved (P < 0.05) feed conversion ratio of barley diets by 11% over the finishing period, but enzyme treatments had no such effect for corn diets. Fibrolytic enzymes can be used to improve the digestibility of barley-based diets, but are not advantageous for corn diets. Further work is necessary to determine optimum formulation and level of application of enzyme preparations for use in barley diets. Further study of the differences in carcass characteristics of cattle fed barley or corn diets is warranted to substantiate the trends observed on this limited group of animals. Key words: Feedlot cattle, barley, corn, enzymes, cellulase, xylanase
Cortisol and β-endorphin responses to physical and psychological stressors in lambs
Authors: Mears G. J. , Brown F. A.
Published: March 2010

Plasma cortisol, β-endorphin, T3 and T4 were determined in lambs before, during and after exposure to stress in order to evaluate the potential use of these hormones to objectively measure stress responses. Lambs were exposed to tail-docking, castration, weaning, isolation, and restraint stress. Twelve ewe and 24 ram lambs were assigned to the experiment, with 12 of the ram lambs surgically castrated when 3-wk old. Tail docking within 24 h of birth did not (P > 0.05) elevate either plasma cortisol or β-endorphin. Castration markedly elevated (P < 0.001) plasma cortisol and β-endorphin within 15 min of surgery. Both hormones were highly elevated for the first 4 h. Plasma cortisol returned to control levels by 24 h whereas β-endorphin was still elevated (P < 0.05) 24 h after castration. Plasma cortisol levels were elevated for the first 60 min following weaning (P < 0.005) and again at 24 h after dam removal (P < 0.001). Plasma β-endorphin was not elevated (P > 0.05) any time during the 72 h following weaning. Plasma cortisol (P < 0.001) and β-endorphin (P < 0.05) were elevated during the first 60 min following the start of 1 h of isolation. Results were similar for partial and total isolation. No effects of isolation were found for the next 23 h. Plasma cortisol (P < 0.005) was elevated during the first 30 min following 4 min of shearing-like restraint, whereas plasma β-endorphin was elevated only at 7 min (P < 0.05) after restraint began. No further effects of restraint were found prior to termination of sample collection at 24 h. None of the stressors employed affected plasma concentrations of T3 and T4. This study has shown that measurements of plasma cortisol and β-endorphin in blood samples obtained before, during and after stress are useful in assessing stress in lambs. The painful stressor, castration, induced marked and prolonged elevations of both hormones, whereas psychological stressors elicited graded, short-term cortisol responses and limited β-endorphin responses. Key words: Cortisol, β-endorphin, physical stress, psychological stress, lambs
Expected genetic responses from selection indexes for Canadian dairy cattle under present and future milk pricing systems
Authors: Sivanadian B. , Lohuis M. M. , Dekkers J. C. M.
Published: March 2010

Expected selection responses and profit under alternative milk pricing scenarios for various selection indexes were compared: Lifetime Profit Index (LPI) with 60:40:0:0 emphasis on production:type:herdlife:somatic cell score and 9:2:0 relative weights on Protein:fat:milk, and Total Economic Value (TEV) reflecting the present pricing system, Neutral Total Economic Value (NTEV) and Future Total Economic Value (FTEV) reflecting future milk prices, each with 64:0:26:10 emphasis on production:type:herdlife:somatic cell score and 9:2:0, 1:0:0 and 18:–2:–5 relative weights, respectively, on protein:fat:milk and Large Herd Operator Index (LHO) with 83:17:0:0 emphasis and 13.5:–1.5:0 relative weights. Among the correlations between indexes the lowest was.93 (correlation of LPI with NTEV and FTEV) and the highest was 0.99 (between TEV and NTEV). For present and probable future milk pricing the most profitable sire selection indexes were TEV and FTEV in both whole and grade-only populations. When selection intensity and number of daughters per sire were equal to 1.0 and 50, respectively, profit expressed in Canadian dollars in net present value of lifetime profit of a milking daughter were 231.75 (226.62 in grade population) and 234.89 (229.89 in grade population) from TEV and FTEV respectively. The choice of sire selection indexes depends on individual farmer goals. However, if the total economic merit resulting from typical dairy production is the goal, then TEV and FTEV are advised for short-term and long term selection, respectively. Key words: Index, selection, genetic response, profit, milk pricing
Regulation of intestinal glucose absorption: A new issue in animal science
Authors: Croom Jr W. James , McBride Brian , Bird Anthony R. , Fan Yang-Kwang , Odle Jack , Froetschel Mark , Taylor Ian L.
Published: March 2010

Intestinal glucose absorption occurs via Na+-dependent glucose cotransporters (SGLT1) located in the luminal membrane of enterocytes and is driven by an electrochemical gradient maintained by Na+/K+ ATPase located on the basolateral membrane. Twenty percent of whole animal energy expenditures can be accounted for by the gastrointestinal tract, most of which is the result of Na+/K+ ATPase function. Active intestinal glucose transport is regulated by a number of gastrointestinal peptides such as epidermal growth factor (EGF) and peptide YY (PYY). PYY and EGF can upregulate intestinal glucose absorption by as much as 200–300%. Of special interest is the fact that the energetic costs of intestinal tissue function can vary in relationship to the amount of glucose transported. This value termed "apparent energetic efficiency of glucose uptake" (APEE) may be of value in evaluating the energetic costs of glucose and other nutrients during various physiological and nutritional states. Recent studies suggest that intensive genetic selection for production traits in poultry may result in intestinal absorption being rate-limiting for full phenotypic expression of these traits. Further research is needed to clarify this issue. Key words: Glucose absorption, intestinal, energy metabolism, peptides, genetic selection
The effects of natural light on measures of meat quality and adrenal responses to husbandry stressors in swine
Authors: Cook Nigel J. , Chang John , Borg Robert , Robertson Wayne , Schaefer Allan L.
Published: March 2010

Two groups of pigs, born and housed under artificial and natural lighting, demonstrated increases in plasma and salivary cortisol levels at the time of weaning (day 24) and following handling and transport, indicating that these husbandry practices are stressful experiences for the animals. Piglets housed under natural light had a mean plasma cortisol response to weaning of 33.7%, compared with 47.9% for pigs in the artificial-lighting condition (P < 0.03). The relative percentage of eosinophils was reduced following weaning in both groups of pigs (P < 0.04). Salivary cortisol levels were significantly increased in response to handling and transport (P < 0.0001). Also, "basal" levels of salivary cortisol were lower in pigs exposed to natural lighting (P < 0.02) but no differences in the magnitude of the response to handling and transport were evident between different lighting conditions. Male pigs raised under artificial lighting had greater fat depth than those raised under natural light (P < 0.03) and a lower lean yield (P < 0.05). The longer photoperiod and full spectrum of natural light probably entrains the circadian rhythm of cortisol to an earlier clock time and are likely to be the major factors in differential cortisol concentrations between lighting conditions. Key words: Lighting, cortisol, saliva, pigs, stress, meat quality
Effect of prolonged backgrounding on growth performance and carcass composition of crossbred beef steers
Authors: Vaage A. S. , McCartney D. H. , McKinnon J. J. , Bergen R. D.
Published: March 2010

One hundred and twenty crossbred steers were fed to slaughter on a high-energy finishing ration (GRAIN), or given barley silage during the winter, grazed 90 d, and then finished on the high-energy ration (FORAGE) to determine the effect of prolonged backgrounding on growth performance and carcass composition. The steers were separated into two weight groups (light vs. heavy, 346 ± 19 vs. 394 ± 16 kg; P < 0.01) and allocated to a feeding program across 12 pens according to a 2 × 2 factorial completely randomized design. The steers were slaughtered by pen at an average USFAT depth of 8 mm. Compared with steers on the GRAIN program, FORAGE steers had lower average daily gains (1.03 vs. 1.62 kg d−1; P < 0.01), took 119 d longer to finish (P < 0.01) and finished at heavier live (626 vs. 578 kg; P < 0.01), and carcass (342 vs. 306 kg; P < 0.01) weights. Heavy animals grew faster (1.37 vs. 1.28 kg d–1, P < 0.01), and were slaughtered 15 d earlier (P < 0.06) at heavier weights (626 vs. 578 kg; P < 0.01) than light animals. Light animals had smaller l. thoracis area than heavy animals (86.8 vs. 93.8 cm2; P < 0.01). The proportion of carcasses with slight or small marbling was greater (P < 0.01) for light steers, particularly those with a higher proportion of "British" breeding. Prolonged backgrounding with forages produced larger carcasses without adversely affecting composition. Key words: Prolonged backgrounding, beef steers, carcass composition
Daily variation in blood enzymes and metabolites in ewes under three levels of feed intake
Authors: Caldeira R. M. , Almeida M. A. , Santos C. C. , Vasques M. I. , Portugal A. Vaz
Published: March 2010

Daily variations in the concentration of albumin, creatinine, non-esterified fatty acids, globulins, glucose, total lipids, total protein, triglycerides, urea, β-hydroxybutyrate, and in the activity of alkaline phosphatases, aspartate aminotransferase, glucose-6-phosphate dehydrogenase, glutamate dehydrogenase, isocitrate dehydrogenase and pyruvate kinase were evaluated in the serum or plasma of ewes fed 30, 100 and 200% of theoretical maintenance energy requirements. A daily profile was observed in almost all variables, which may be of importance when interpreting data for these blood indicators. Daily variations were found even for albumin and total protein serum concentrations, showing a significant decrease of their levels after the meal. In order to maximize the diagnostic value of these indicators, the most suitable times for blood collection seem to be 16 h after the meal and (or) just before the meal. Collection 16 h after the meal apparently allows the characterisation of a relatively steady metabolic state, intermediate between the effects of food intake and the final phase of the intensification of body reserve mobilization. Collection just before the meal will give a good indication of the level of activity of those mobilization mechanisms. Key words: Blood, metabolites, enzymes, profiles, sheep
Changes in the microbial population of a rumen-simulating fermenter in response to yeast culture
Authors: Newbold C. J. , McIntosh F. M. , Wallace R. J.
Published: March 2010

Yeast increased the total viable count of bacteria on a medium containing rumen fluid and soluble sugars by 38% (P < 0.05) and the cellulolytic population increased by 49%, although the increase was not statistically significant (P > 0.05). Microscopic counts indicated a 25% increase in total bacteria (P < 0.05). Bacterial counts with mannitol as sole energy source also increased (P < 0.05), indicating an increased Selenomonas population; that was not in itself sufficient to account for the increase in the total bacterial count. The protozoal population was significantly lower in yeast supplemented vessels (P < 0.001), which may account partly for the increased bacterial numbers. Key words: Yeast culture, probiotics, rumen bacteria, Rusitec
Insulin responses during glucose tolerance tests in steers with increasing Wagyu genetic influence
Authors: Mir P. S. , Mears G. J. , Ross C. M. , Husar S. D. , Robertson W. M. , Jones S. D. M. , Mir Z.
Published: March 2010

Intravenous glucose tolerance tests (IVGTT) were conducted in 18 steers with 0, 50 and 75% Wagyu genetic influence. Glucose clearances were similar for all steers. Plasma insulin concentrations (basal, 5 and 10 min post-infusion) were higher (P < 0.05) in 0% Wagyu steers (2.57, 7.36, 9.68 ng mL−1) relative to 50% Wagyu (1.17, 2.59, 5.34 ng mL−1) or 75% Wagyu (0.99, 2.78, 5.00 ng mL−1). A correlation coefficient of 0.71 (P = 0.005; n = 15) between marbling score of carcasses and plasma glucose concentration 90 min after glucose infusion suggests, possible associations among the propensity of cattle with Wagyu genetic influence to marble, mechanisms of glucose utilization and nature of the insulin response to circulating glucose. Key words: Plasma glucose, insulin, marbling, Wagyu
Plane of nutrition and folic acid supplementation between birth and four months of age on mammary development of dairy heifers
Authors: Petitclerc D. , Dumoulin P. , Ringuet H. , Matte J. , Girard C.
Published: March 2010

Forty-seven dairy heifers of approximately 10 d of age were assigned randomly to a 2 × 2 factorial design to study the effects of folic acid supplementation (0 vs. 40 mg) administered weekly i.m. and levels of feed intake after weaning on mammary development. Folic acid treatment started immediately and all heifers were weaned 5 wk later. Heifers were then either fed ad libitum grass hay and concentrates or restricted to a body weight gain of approximately 700 g d−1 until slaughter at 4 mo of age. Average daily gain was affected by feed intake level after weaning (615 vs. 954 g d−1P < 0.01); however, folic acid supplementation increased weight gain only during the 5-wk period following weaning (P < 0.05). Heifers fed ad libitum were 33% heavier before slaughter (P < 0.001) but there was no effect due to folic acid supplementation (P > 0.05). There was no effect of treatments on serum prolactin and growth hormone concentrations (P > 0.05); overall, prolactin increased and growth hormone decreased over the 16-wk sampling period. However, serum IGF-1 concentrations were significantly higher in heifers fed ad libitum following weaning as compared with the feed-restricted animals (P < 0.001); overall, IGF-1 concentrations increased linearly between weeks 2 and 16 (P < 0.001). Plane of nutrition did not have any effect (P > 0.05) on the total volume of parenchymal tissue in the mammary gland (61.6 vs. 63.6 cm3); however, ad libitum feeding increased significantly (P < 0.001) the volume of extraparenchymal tissue in the gland (262.0 vs. 1067.6 cm3). After adjusting data for the difference in body weight at slaughter, the amount of parenchymal tissue was smaller in animals fed ad libitum (P < 0.05); this adjustment did not change the effect of plane of nutrition on mammary extraparenchymal tissue. In conclusion, a fast rate of gain after weaning up to 4 mo of age induced a large accumulation of mammary fat, but did not negatively affect the total amount of parenchymal tissue in the mammary gland of dairy heifers. Key words: Plane of nutrition, folic acid, mammary gland, IGF-1
Evaluation of diacylglycerol acyltransferase as an indicator of intramuscular fat content in beef cattle
Authors: Middleton C. K. , Kazala E. C. , Lozeman F. J. , Hurly T. A. , Mir P. S. , Bailey D. R. C. , Jones S. D. M. , Weselake R. J.
Published: March 2010

The development of a biochemical or molecular marker for predicting the propensity for cattle to deposit intramuscular (i.m.) fat would reduce the time required to improve for this trait. In the current study, diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) activity was investigated as a potential biochemical marker for predicting the deposition of i.m. fat. The activities of DGAT were determined in microsomal fractions of subcutaneous (s.c.) adipose tissue, i.m. adipose tissue and muscle tissue sampled from Wagyu crossbred cattle at slaughter weight. The i.m. adipose and muscle tissues were dissected from the pars costalis diaphragmatis (p.c.d.) muscle. The lipid content (LC) of the p.c.d. muscle correlated with the LC of the longissimus muscle (r = 0.51; P < 0.05). There was an inverse correlation between p.c.d. i.m. adipose tissue DGAT specific activity and LC of the p.c.d. (r = −0.50; P < 0.05) suggesting that DGAT activity was down-regulated as i.m. adipose tissue became filled. There was a strong correlation (r = 0.74; P < 0.001) between DGAT total activity in i.m. adipose tissue and muscle DGAT total activity, suggesting DGAT activity is coordinately regulated in these two tissues. Key words: Bovine, intramuscular fat, diacylglycerol acyltransferase, Bos taurus
Herbage yield and cattle preference for dryland pasture grasses
Authors: McCaughey W. P.
Published: March 2010

In a 3-yr pasture trial, herbage yield and cattle preference were recorded on a small plot area which was mob-grazed by cattle. Sampling grazed plots with quadrats had greater variability associated with the technique than traditional mechanical harvesting techniques, but the technique allowed grazing to continue on the remaining plot area so that other information such as cattle preference ratings could be collected. Results indicated that differences (P < 0.001) in herbage yield between cultivars could be detected despite having greater coefficients of variation than traditional mechanical harvesting methods and that differences (P < 0.001) in cattle preference could be determined using visual rating scores. Key words: Grass, cattle, preference, yield, forage
Effect of feeding formaldehyde- and heat-treated oil seed on milk yield and milk composition
Authors: Tymchuk S. M. , Khorasani G. R. , Kennelly J. J.
Published: March 2010

The primary objective of this study was to determine the effect of formaldehyde-treated oil seed on milk composition, with particular emphasis on the fatty acid and protein composition of milk. Ground and heat-treated canola seed treatments were included for comparison purposes. Four early-lactation Holstein cows were assigned to four treatments in a 4 × 4 Latin square design. Cows were fed a control diet containing 60% concentrate, 20% alfalfa silage and 20% barley silage (DM basis). The concentrate portion was based on rolled barley, canola meal, and ground corn. Canola seed replaced barley and canola meal in the control diet at 5% on a DM basis. Dry matter intake (21.0 ± 0.1 kg d−1), milk yield (33.3 ± 1.57 kg d−1), milk component yield and milk protein and lactose percentages were not affected (P > 0.05) by dietary treatment. Cows fed untreated ground canola seed had lower (P < 0.05) milk fat percentage than cows fed the other treatments. The addition of untreated and heat-treated canola seed reduced palmitic acid (15%) and increased oleic acid (14%), but had no effect on linoleic and linolenic acid concentrations. Formaldehyde treatment resulted in a 76 and 123% increase in C18:2 and C18:3, respectively over the control diet, whereas untreated and heat-treated canola seed did not influence the concentration of these fatty acids. Effects of treatments on milk protein and non-protein nitrogen components were minor or nonexistent. Transfer efficiencies calculated for linoleic and linolenic acid indicated that formaldehyde treatment was efficacious in significantly reducing the extent of biohydrogenation of fatty acids in the rumen. Key words: Canola seed, dietary fat, dairy cattle, milk composition
Effects of early versus late spring calving on beef cow-calf productivity
Authors: Pang H. , Makarechian M. , Goonewardene L. A. , Berg R. T.
Published: March 2010

Early (April) vs. late (May/June) calving was compared over 3 yr at the University of Alberta Ranch at Kinsella, Alberta, Canada. Three synthetic lines, two of which were predominantly beef breeds (BS1 and BS2) and one with approximately 60% dairy breeding (DS) were used and 995 records were analyzed. Cows from each line were randomly allotted to the early or late breeding schedules at the time of breeding. The same bulls bred cows in their own line, beginning in June and in August for two 6-wk periods. Calving season had no significant effect (P > 0.05) on pregnancy rate (%), calving assistance, calving and weaning rate (%), adjusted off-test weight or post-weaning ADG, suggesting that late calving can be a viable management option. Birth weights of all calves were significantly lower in the early group than in the late group (38.9 vs. 41.2 kg, P < 0.01). In the BS1 and BS2 lines, early calves had higher adjusted pre-weaning ADG: BS1 (1.18 vs. 1.11 kg d−1, P < 0.01), BS2 (1.12 vs. 1.05 kg d−1, P < 0.01) but the differences in the DS line were not significant (P > 0.05). The early calves were older at weaning and therefore were expected to have higher pre-weaning ADG. The fact that the late-born calves in the DS line equalled the early calves in pre-weaning ADG indicates that they were growing relatively faster. Late calving DS heifers had significantly higher weights (P < 0.01) at breeding in June, higher ADG to breeding, and cows had higher body condition scores at calving and weaning (P < 0.01), suggesting that DS cattle benefited more by late calving. The late-calving management system appears to be a viable option for cow-calf production in Alberta. Key words: Calving season, reproductive traits, weight and growth, beef cattle
Effects of mechanical treatment of whole canola seeds on carcass composition and blood lipids of lambs fed grass silage
Authors: Huard S. , Seoane J. R. , Petit H. V. , Fahmy M. H. , Rioux R.
Published: March 2010

Thirty-three lambs (25.2 ± 2.7 kg BW) were used to study if mechanical treatment of canola seeds can exert an effect on carcass quality, blood lipids, and fatty acid profile of depot fat. All lambs received a basal diet of 179 g d−1 of a 16% CP commercial concentrate and grass silage fed ad libitum. The basal diet was supplemented with the following dietary treatments (dry matter basis): C, a control supplement supplying 182 g of a mixture of 66% canola meal and 34% canola oil; WCS, 187 g of whole canola seeds; RCS, 188 g of rolled canola seeds; and GCS, 189 g of ground canola seeds. Dressing percentage was higher (P < 0.05) for diet C (45.6%) than for WCS (42.5%) and RCS (41.9%). The highest and lowest carcass grades were obtained with diets C and RCS, respectively (P < 0.05). Blood lipid concentrations increased as the lambs grew older (P < 0.01). Lambs fed the GCS diet had lower plasma concentrations of total cholesterol and high density lipoprotein cholesterol than lambs fed the WCS or RCS diets (P < 0.05). Kidney fat of lambs on the C diet contained more trans -C18:1 and less C18:0 compared with the other diets (P < 0.01). The utilization of untreated or rolled canola seeds as protein and fat supplements decreased carcass quality, increased blood triglycerides and changed fatty acid composition of depot fat. Key words: Canola seeds, lambs, carcass composition, blood lipid
Intrabreed polymorphic information content of microsatellites in cattle and sheep
Authors: Buchanan Fiona C. , Thue Tracey D.
Published: March 2010

Eight ovine and eleven bovine microsatellites were amplified in unrelated individuals from five breeds of sheep and cattle respectively. Polymorphic information content (PIC) was calculated for each breed. It was shown that the common practice of using genotypes from several breeds to calculate PIC for a livestock species can give misleading PIC values for a given breed. Key words: Microsatellite, polymorphic information content
The effect of a flooding dose of phenylalanine on indicators of metabolic status in pigs
Authors: Nyachoti C. M. , Lange C. F. M. de , McBride B. W.
Published: March 2010

The metabolic effect of infusing growing pigs with a large dose of phenylalanine was investigated. Packed cell volume and plasma glucose levels were not affected (P > 0.05), while plasma insulin concentration was increased at some time periods compared to a saline control (P < 0.05). For amino acids, only phenylalanine and tyrosine concentrations were increased (P < 0.05) by phenylalanine infusion. A flooding dose of phenylalanine may not significantly alter the metabolic status of the pig and could therefore be used in measuring protein synthesis in pigs. Key words: Amino acid, flooding dose, glucose, insulin, phenylalanine, pig
Whole-body protein synthesis in growing barrows: diurnal and day-to-day variation and the effect of site of tracer infusion and sampling
Authors: Roy N. , Lapierre H. , Estrada R. , Bernier J. F.
Published: March 2010

In the first experiment, two catheters were placed in one of three sites for infusion and sampling (vena cava and vena cava with 7 cm between catheter tips, VC/VC, n = 5; right ventricle and atrium, RV/RA, n = 5; anterior aorta and left ventricle, AA/LV, n = 4) to determine the effect of site on the measurement of CO2 and leucine kinetics. Pigs received a 6-h continuous i.v. infusion of NaH13CO3 (1.45 µmol h−1 kg−1, preceded by a priming dose of 2.05 µmol kg−1) and of L[1-13C]leucine (9.7 µmol h−1 kg−1, preceded by a priming dose of 9.7 µmol kg−1), the following day. No effect (P > 0.10) of site was observed on NaH13CO3 recovery rate, leucine irreversible loss rate (leucine ILR) and leucine used for protein synthesis (LS). A tendency (P < 0.10) for increased leucine oxidation (LO) was observed with the VC/VC compared to the RV/RA sites. In the second experiment, six growing barrows with catheters in the VC/VC site were infused as earlier with NaH13CO3 and L[1-13C]leucine for three different 6h periods (12:00 to 18:00 h, first day; 20:00 to 02:00 h, night; 12:00 to 18:00 h, second day) to determine the diurnal and day-to-day variation of CO2 and leucine kinetics. No effect (P > 0.10) of period was observed on NaH13CO3 recovery rate, leucine ILR and LS. The LO was lower (P < 0.05) on the second day compared with the first day (day-to-day variation) while similar (P > 0.10) LO was observed between the first day and night (diurnal variation). Together, these results indicate that 1) the VC/VC site can be used for L[1-13C]leucine and NaH13CO3 infusions, 2) NaH13CO3 recovery studies can be performed either the day preceding or following the measurement of substrate and 3) protein synthesis estimated from a 6-h infusion period can be extrapolated to the 24 h periods under conditions of frequent feeding. Key words: Pigs, leucine, protein synthesis, tracer techniques, diurnal variation
Effects of handling, shearing and previous exposure to shearing on cortisol and β-endorphin responses in ewes
Authors: Mears G. J. , Brown F. A. , Redmond L. R.
Published: March 2010

The objectives of the study were to compare the effects of handling and shearing on plasma cortisol and β-endorphin levels of ewes and to determine if adaptation to annual shearing occurred. Plasma cortisol and β-endorphin concentrations were determined during either handling only or handling plus shearing in 12 ewes previously exposed to annual shearing (1–4 times) and in 12 naïve ewes. The handling process consisted of four steps: 1) moving ewes from their quarters into the shearing room; 2) moving them in groups of four into a holding pen; 3) moving them in pairs to a shearing platform where they were up-ended and restrained as in shearing; and 4) moving them into another holding pen in the shearing room. Half of the ewes were sheared during step 3 of the handling process. Handling and shearing elevated (P < 0.0001) plasma cortisol and β-endorphin concentrations, but the responses to the handling process and to the handling plus shearing process were similar (P > 0.1). Moving the ewes from their quarters to the shearing platform resulted in significantly higher plasma cortisol, which remained elevated for 60 min. Plasma β-endorphin was only transiently elevated after shearing was completed. Previous exposure to shearing enhanced the cortisol (P < 0.001) and β-endorphin (P < 0.05) responses to handling and shearing. Both responses were significantly greater and longer in the ewes sheared previously. The results indicate that the stress response to handling was equivalent to that of handling plus shearing, and that the stress response was much greater in ewes previously exposed to annual shearing. Key words: Cortisol, β-endorphin, negative adaptation, shearing, stress, ewes
The effects of porcine somatotropin administration and gender on cooking properties and palatability attributes of pork muscle
Authors: Jeremiah L. E. , Schaefer A. L. , Kruger G.
Published: March 2010

Loin roasts and ham steaks from 120 Yorkshire pigs (60 barrows and 60 gilts) were utilized to evaluate the effects of porcine somatotropin (PST) treatment and gender on cooking properties and palatability attributes. Within each gender, pigs were randomly allocated to the following three treatments: 1) control, 2) prolonged-release PST implants (2 mg d−1), or 3) daily subcutaneous PST injections (2 mg d−1). All animals received a 17% crude protein diet, ad libitum. Animals received PST treatments within a body weight range of 70 ± 5 kg to 96 ± 5 kg. All animals were slaughtered and processed using simulated commercial procedures. Longissimus lumborum (loin) roasts (lumbar) and cured and smoked semimembranosus (SM) steaks were roasted to 75 and 60 °C, respectively, in a 177 °C oven, sub-sampled, and evaluated by an eight-member sensory panel. No differences in cooking properties or palatability attributable to gender were observed (P > 0.05). However, cured and smoked SM steaks from pigs receiving daily PST injections were more tender both initially and overall (P < 0.05) than their counterparts from control pigs. In addition, cured and smoked SM steaks from pigs receiving daily PST injections had less perceived connective tissue (P < 0.05) than their counterparts from control pigs and pigs receiving prolonged-release PST implants. The cooked loins from pigs receiving prolonged-release PST implants were perceived to contain less connective tissue than their counterparts from control pigs and pigs receiving daily PST injections (P < 0.05), but cooked loins from pigs receiving prolonged-release PST implants had less-desirable flavour (P < 0.05) than their counterparts from pigs receiving daily PST injections. It should be noted, however, only the tenderness differences observed in the cured and smoked SM were of sufficient magnitude to be of practical importance. Consequently, it would appear PST treatments, particularly daily injections, can be utilized to achieve previously reported, potential production and carcass composition advantages, while possibly improving the eating quality of some pork products. Key words: Pork, somatotropin, PST, gender, cooking properties, palatability attributes
Acute heat-stress effects on physiology and fear-related behaviour in red jungle fowl and domestic fowl
Authors: Zulkifli I. , Dass R. T. , Norma M. T. Che
Published: March 2010

Two experiments were conducted to compare heat tolerance of red jungle fowl (RJF) and commercial broilers (CB) at (i) a common age and (ii) a common body weight. In exp. 1, RJF and CB of a common age (8 wk) were exposed to 36 ± 1°C for 6 h. RJF had smaller increases in heterophil to lymphocyte ratios and body temperature and higher serum cholesterol concentrations than CB in response to the heat treatment, while tonic immobility (TI) measurements were not affected by heat stress. In exp. 2, RJF and CB of a common body weight (1000 ± 150 g) were subjected to similar procedures as in exp. 1 (except TI durations). Both breeds responded similarly to the heat treatment. In both experiments, RJF had higher serum glucose level than CB, and the trait was not affected by heat exposure. Key words: Heat stress, physiology, fear, jungle fowl, broilers