bluuebunny/crossref_metadata_2025 huggingface dataset:
Feedlot performance, carcass composition and meat quality of free-range reared pigs
Authors: Sather A. P. , Jones S. D. M. , Schaefer A. L. , Colyn J. , Robertson W. M.
Published: March 2010

The effects of the housing system (confinement versus free-range) and season (summer versus winter) on growth performance, carcass composition and meat quality were determined from commercial pigs with known NN genotype at the halothane locus. Free-range-housed pigs reared from 25 to 105 kg required 16 ± 1.2 (SEM) more days to reach market weight compared with confinement-housed pigs. Housing did not affect feed requirements during the summer, but food consumption increased by 13.7% for free-range pigs during the winter. Confinement-reared pigs had a 0.75 ± 0.28 kg heavier commercial carcass weight than free-range-reared pigs. While there was no difference in carcass fat thickness, muscle depth was 2.4 ± 1.02 mm greater in free-range-reared pigs with increased predicted lean yield from 59.1 ± 0.24% to 59.8 ± 24%. Free-range-reared pigs had heavier butts, loins and hams, and lighter bellies, which increased their wholesale carcass value by 2.9%. Furthermore, they had greater dissected lean in the picnic (2.0%) butt (4.0%), loin (4.5%) and ham (2.0%) with no compromise to pork quality. If the wholesale price is adjusted for the increased lean content of each cut by an additive or multiplicative model, apparent value was further increased to 5.7 or 8.1%. While these results suggest a beneficial effect on carcass merit when rearing hogs in outdoor facilities, they further suggest potential benefits to carcass grading using developing technologies that recognize differences in carcass conformation. Key words: Animal ethics, Landrace, carcass value, housing systems
Effects of barley cultivar on energy and nitrogen metabolism of lambs
Authors: Ovenell-Roy K. H. , Nelson M. L. , Westburg H. H. , Froseth J. A.
Published: March 2010

The aim of this research was to compare energy values, nitrogen metabolism and diet digestibility of four barley (Hordeum vulgare L.) cultivars grown in two different years, to identify the most important factors affecting variation. Six wether lambs (39.4 ± 1.6 kg) were assigned within period in a randomized complete block design to barley cultivar (1990 Camelot, 1990 Cougbar, 1990 Steptoe, 1991 Boyer, 1991 Camelot and 1991 Steptoe) and consumed a diet of 83% barley, 10% alfalfa pellets and 7% supplement on a DM basis. During each 14-d period, feed, orts, fecal and urine samples were collected during the last 7 d and methane emissions were quantified. Digestibility of NDF polymeric monosaccharides was lower (P < 0.10) for weathers fed 1990 Steptoe than all cultivars other than 1991 Boyer and was positively correlated to methane production (r = 0.52). Barley DE was not different among cultivars but, because methane production was greater (P < 0.10) for lambs fed 1991 Boyer (38 L d−1) than for those fed 1990 Steptoe (21 L d−1) and 1990 Camelot (26 L d−1), barley ME content of 1991 Boyer (12.3 MJ kg−1 OM) was lower (P < 0.10) than for 1990 Steptoe (13.4 MJ kg−1 OM). Nitrogen digestibility in lambs fed Camelot grown both years was greater (P < 0.05) than for most cultivars. Absorbed nitrogen was greatest (P < 0.10) in lambs fed 1991 Camelot and nitrogen retention (g d−1) tended to be greater than 1990 Cougbar (P = 0.14) and 1990 Camelot (P = 0.16) fed lambs. Cougbar, Boyer and 1991 Steptoe had lower feeding quality for ruminants because of lower energy and/or nitrogen metabolism, while both years of Camelot and 1990 Steptoe had greater ME values. Methane production, digestibility of NDF polymeric monosaccharides and nitrogen metabolism were major factors contributing to variability among barley cultivars within and between years. Key words: Barley, lambs, methane, metabolizable energy
Effects of branding on weight gain, antibiotic treatment rates and subsequent handling ease in feedlot cattle
Authors: Schwartzkopf-Genswein K. S. , Stookey J. M. , Janzen E. D. , Mckinnon J.
Published: March 2010

Two trials were conducted to investigate the effects of hot-iron and freeze branding on individual body weight (BW) antibiotic treatment (AT) rates based on rectal temperature (RT), and subsequent handling ease in feedlot cattle. Charolais-cross steer calves were ear-tagged and vaccinated on arrival to the feedlot and assigned to freeze brand (F), hot-iron brand (H), or control (C) treatments. Animals were branded at arrival to the feedlot in Trial 1 (n = 300) and 20 d after arrival in Trial 2 (n = 248). Rectal temperatures, AT and BW of all animals were recorded on the day of branding and every second day for 10 d. Branding treatments had no effect on average daily gain (ADG) or AT rates in either trial. Steers in Trial 2 required increased handling pressure over the 10 d period, indicating some aversion to being caught in the chute for measurement of RT. The only effect of treatment on handling ease was that freeze branded steers required more (P < 0.005) handling pressure than C or H steers on d 6 after branding. This may have resulted from discomfort caused by pressure put on the freeze branding site while in the chute, perhaps indicating that F animals may experience a lingering pain. Branding, regardless of technique, does not affect BW or AT rates when performed soon after arrival or following a 20 d acclimation period in the feedlot. These findings suggest that branding may not be a severe enough stressor to negatively affect BW gain or health in cattle. There may be some potential in using handling ease as an indicator of an animal's aversion to re-enter the location of a previously negative experience. Key words: Cattle, Branding, Behaviour, Liveweight Gain, Body Temperature
Performance of growing lambs fed grass silage with raw or extruded soybean or canola seeds
Authors: Petit Hélène V. , Rioux Romain , D'Oliveira P. S. , Prado I. N. do
Published: March 2010

Thirty-two Outaouais male lambs were assigned to a completely randomized design with a 2 × 2 factorial arrangement of treatments to determine the effect of extrusion of full fat seeds on performance and carcass quality. Raw (NE) and extruded (EX) isonitrogenous and isoenergetic mixtures of barley and either full fat soybean (SB) or canola seed (CA) were fed at a daily rate of 424 and 400 g, respectively. Lambs were fed silage ad libitum from 20 to 43 kg. Intakes of silage DM and total DE were similar among treatments. The ADG and concentration of total polyunsaturated fatty acids (FA) in muscle were higher for lambs fed EX than NE seeds and the effect was greater for SB than CA mixture; this tended (P = 0.06) to result in an interaction between seed and extrusion for polyunsaturated FA in muscle. Similar trends were observed for feed efficiency. This could reflect the response to heat treatment as extrusion significantly reduced N degradability of SB mixture but had no effect on that of CA mixture. Digestibilities of DM, N, and energy were higher (P < 0.10) for lambs fed SB than for lambs fed CA mixture and extrusion had no effect. Data suggest that extrusion of seeds can be used to improve performance of lambs fed a high forage diet and modify FA composition of the carcass. Key words: Sheep, canola, soybean, carcass, extrusion
Effect of grazing system, stocking rate and season of use on herbage intake and grazing behaviour of stocker cattle grazing alfalfa-grass pastures
Authors: Popp J. D. , McCaughey W. P. , Cohen R. D. H.
Published: March 2010

An experiment was conducted to determine the effects of grazing system (continuous and rotational), stocking rate (light, 1.1 steers ha−1; heavy, 2.2 steers ha−1) and season of use on forage intake and grazing behaviour of stocker cattle grazing an approximately 70% alfalfa (Medicago sativa L.), 25% meadow bromegrass (Bromus biebersteinii Roem & Schult.) and 5% Russian wildrye (Psathyrostachys juncea (Fisch.) Nevski) pasture. To determine organic matter intake, grazed herbage was collected with esophageal fistulated cattle and analyzed for in vitro digestible organic matter while fecal output was determined using chromic oxide. These variables were used to calculate organic matter intake. Daily herbage consumption (g OM kg BW−0.75 d−1 and kg OM d−1) did not differ (P > 0.05) for either grazing system or stocking rate from 1991 to 1993, with the exception of greater (P < 0.05) intakes at light compared with heavy stocking rates (10.9 vs. 8.4 kg OM d−1) late in the 1991 season. Grazing time was usually lower (8.9 vs. 10.3 h (3-yr mean); P < 0.05) in lightly than in heavily stocked pastures. As available herbage increased, cattle spent less time grazing (y = 12.46 − 0.00103 x; r = 0.48, RSD = 2.04, P < 0.001; where y = grazing time and x = herbage mass). Biting rates ranged from 28 to 32 bites min−1, regardless of year, season, grazing system or stocking rate. Rate of intake (g OM kg−1BW−0.75 h−1) did not differ (P > 0.05) for either grazing system, although it tended to be greater (P < 0.10) at light than at heavy stocking rates. As animals in lightly stocked pastures spent less time grazing, herbage was consumed at an increased rate, which was reflected in increased average daily gain (y = 0.28 + 0.067 x; r = 0.86, RSD = 0.14, P < 0.001; where y = daily gain and x = intake rate). Our results suggest that daily herbage consumption was not affected by grazing system or stocking rate; however, at lower stocking rates, grazing time declined and intake rate tended to increase. Key words: Alfalfa, cattle, ingestive behaviour, pasture
Effects of selection for lower backfat, and increased levels of dietary amino acids to digestible energy on growth performance, carcass merit and meat quality in boars, gilts, and barrows
Authors: Grandhi R. R. , Cliplef R. L.
Published: March 2010

Two experiments were conducted, using a total of 288 crossbred boars, gilts and barrows from the progeny of two Yorkshire sow lines, one kept as control, and the other selected for lower backfat thickness and increased growth rate for six generations. The lysine to DE (g MJ−1) levels used during grower (20 to 60 kg) and finisher (60 to 105 kg) periods, respectively, in the three diets (14.2 MJ DE kg−1) were: 1) 0.53 and 0.42 with no other supplemental amino acids except lysine, 2) 0.69 and 0.57 with supplemental threonine and methionine at a ratio of 0.65 and 0.30 to dietary lysine and 3) 0.85 and 0.72 with supplemental threonine and methionine at similar ratios as in diet 2. Feeding diets 2 and 3 increased (P < 0.05) the ADG and feed conversion efficiency of all pigs in both experiments, and this response was mainly during the grower period. Feeding diet 3 improved the growth rate more than diet 2 only in boars and gilts but not barrows. It also increased the feed conversion efficiency in exp. 2. The increased feed conversion efficiency response was higher in select than control line pigs, and in boars. Feeding diets 2 and 3 also improved the carcass merit but reduced the meat quality with an increased firmness and reduced marbling, juiciness, and flavour. The overall results indicated that an average daily intake of approximately 17 g of lysine (0.74 g MJ−1 DE), 11 g of threonine and 5 g of methionine during the grower period and 25 g lysine (0.62 g MJ−1 DE), 18 g threonine and 8 g methionine during finisher period optimized the growth performance, lean growth rate and carcass merit. This response tended to be higher in select than control line, and in boars and gilts than barrows. Key words: Lysine, amino acids, energy, growth, carcass, pigs
Seasonal changes in quality and botanical composition of a rotationally grazed grass-legume pasture in southern Ontario
Authors: Marshall S. A. , Campbell C. P. , Buchanan-Smith J. G.
Published: March 2010

Seasonal changes in quality and botanical composition of a grass-legume pasture were investigated under a controlled rotationally grazed system. A 19.2-ha area divided into sixteen 1.2-ha fields, each subdivided into eight paddocks, was grazed by 40 cows with calves over three consecutive summers. Grazing was managed by setting target sward heights for exit of each paddock between 8 and 10 cm and allowing at least 25 to 30 d for regrowth. Herbage growth in those paddocks not grazed by cow-calf pairs was consumed by yearling heifers on a "put and take" basis. Paddocks were topclipped at 10 cm and fertilized with 34 kg ha−1 of N immediately following the second grazing cycle. Botanical composition changed both within and among the grazing seasons. Legume content of the pasture increased (P < 0.05) throughout the grazing season, while grass content declined (P < 0.05) across all 3 yr. The amount of weeds and dead material averaged 8.9 and 3.8%, respectively, over the 3 yr. Crude protein (CP), in vitro organic matter digestibility (IVOMD), soluble protein (% total CP), rumen degradable protein (RDP) (%total CP) and metabolizable energy (ME) decreased (P < 0.05) from May to June in each season and then increased (P < 0.05) to or surpassed levels seen at the beginning of the grazing seasons (May). Neutral detergent fibre (NDF) and acid detergent fibre (ADF) content increased (P < 0.05) during June and July and were lowest in the spring and the fall across all 3 yr. Mean entry sward heights were 24.8, 30.3 and 28.1 cm for years 1, 2 and 3, respectively. Pre-grazing sward height was negatively correlated to CP (n = 786, r = −0.38, P < 0.0001) and IVOMD (n = 786, r = −045, P < 0.0001), but positively related to NDF (n = 786, r = 0.43, P < 0.0001) and ADF (n = 786, r = 0.68, P < 0.0001) across all 3 yr. The highest CP and IVOMD of the pasture were measured at a sward height of between 12 and 15 cm. Pasture quality varied both within and across all three grazing seasons but remained relatively high and was influenced by botanical composition and sward surface height. Key words: Pasture, quality, botanical composition, grass-legume
Straw yields and nutrients of seventy-five Canadian barley cultivars
Authors: Narasimhalu P. , Kong D. , Choo T. M.
Published: March 2010

Straw, grain, and total yields were compared among 32 two-row and 43 six-row barley (Hordeum vulgare L.) cultivars registered in eastern and western Canada, that were grown at Charlottetown, Prince Edward Island in 1991 and 1992. Straw nutrients was determined in 1991. Two-row cultivars yielded more straw and less grain than six-row cultivars (P < 0.05). The total yield (i.e., total aboveground dry matter) of two-row cultivars was approximately equal to that of six-row cultivars. Straw of two-row cultivars contained more cell contents but less hemicellulose, total-N, Ca, Na, Mn, and Zn than six-row cultivars straw (P < 0.05). Straw yields were not different between eastern and western cultivars regardless of whether they were two-row or six-row types. Eastern two-row cultivars showed higher grain yield and higher total yield than western two-row, and their straws contained less lignin and P than those of western cultivars. Straw of eastern six-row cultivars contained less Ca, but more Na and Mg than that of western six-row cultivars. Hulless barleys showed less grain yield and their straw contained less cellulose than covered barleys regardless of whether they were two-row or six-row types. Two-row hulless cultivars yielded more straw than two-row covered barleys. Straw of six-row hulless barleys contained more cell contents, total-N, and minerals (except for Na and Mn) than that of six-row covered barleys. Key words: Barley cultivars, straw, yield, crude protein, fibre, minerals
Effect of increasing the proportion of dietary concentrate for dairy cows on the composition of ruminal contents and faeces and physico-chemical characteristics of duodenal digesta
Authors: Mir P. S. , Mir Z.
Published: March 2010

An experiment was conducted with six dairy cows in a twice replicated 3 × 3 Latin square design, to determine the chemical composition of ruminal contents and faeces and physico-chemical characteristics of duodenal digesta including, viscosity, pH, titratable acidity, microbial protein, total protein, starch and cell wall components. The cows were fed ad libitum, long alfalfa hay (CP = 16.6%) and a concentrate (CP = 17%) in the ratios of 79:21, 50:50 or 23:77 and the effect of diet on digest characteristics was determined to establish an association among diet composition, digesta characteristics and feed utilization. Feed intake was highest for cows fed hay and concentrate in equal proportions (20.9 kg d−1) and greater (P < 0.05) than that of cows consuming 77% concentrate (17.2 kg d−1). Increasing the proportion of dietary concentrate from 50 to 77% did not alter the composition of ruminal contents from the cows. However, content of crude protein was lower (P < 0.05) and that of cell wall components was higher (P < 0.05) in cows consuming the 21% concentrate relative to those consuming 50 or 77% concentrate. Increasing the proportion of dietary concentrate resulted in linear increases (P < 0.05) in viscosity of the supernatant from duodenal digesta, dry matter and protein content. However, a linear decrease (P < 0.05) in microbial protein in duodenal digesta was observed. A quadratic increase (P = 0.05) in starch content and linear declines (P < 0.05) in content of cell wall components in duodenal digesta with increasing dietary concentrate was observed. Content of crude protein and cell wall components in faeces was different (P < 0.05) for cows consuming the three levels of concentrate. Results indicate that the proportion of dietary concentrate affects viscosity of duodenal digesta which may be due to the presence of starch and cell wall components of digesta entering the duodenum and these characteristics may affect nutrient absorption from the small intestine. Key words: Ruminal contents, duodenal digesta, viscosity, titratable acidity, microbial protein
A preliminary evaluation of growth and carcass traits in Alpine and Boer goat crosses
Authors: Goonewardene L. A. , Day P. A. , Patrick N. , Scheer H. D. , Patrick D. , Suleiman A.
Published: March 2010

Birth weights of Boer (BO) sired kids were 9% higher than Alpine (AL) sired kids. Weaning, 160 d weight and preweaning average daily gain (ADG) were similar for the AL × AL, AL × SA and BO × AL. Breed of dam was significant (P < 0.02) for birth, weaning, 100-d weight, and preweaning ADG. Similar dressing percentage (DP) and ribeye muscle area (REA) were observed among AL × AL, AL × SP, and BO × SP crosses. Key words: Crossbreeding, Boer, Alpine, growth, carcass, ultrasound
Reduced level of creatine kinase in the plasma of Holstein cows supplemented with d-α-tocopherol acetate
Authors: Simpson M. V. , Hidiroglou M. , Batra T. R. , Zhao X.
Published: March 2010

The effects of daily supplementation of 1000 IU of either d-α-tocopherol acetate or dl-α-tocopherol acetate to Holstein cows from drying off to 8 wk post-partum on plasma creatine kinase and selenium levels in plasma and red blood cells were studied. Supplementation with either d-α-tocopherol acetate or dl-α-tocopherol acetate showed no effect on selenium levels in both plasma and red blood cells. However, supplementation with d-α-tocopherol acetate, but not dl-α-tocopherol acetate decreased plasma creatine kinase significantly (P < 0.05) prior to parturition. Key words: Vitamin E, creatine kinase, selenium
Effect of diet and probiotic addition on chemical composition of free or particle-associated bacterial populations of the rumen
Authors: Chiquette J. , Benchaar C.
Published: March 2010

Eight dairy heifers (297 ± 11 kg) fitted with a ruminal cannula were used in this study. The following diets were fed in a replicated, concurrently run 4 × 4 Latin square design: 1) 80% chopped timothy hay + 20% rolled barley (HF); 2) HF + 10 g head d−1 of a mixture of Saccharomyces cerevisiae and Aspergillus oryzae (HF + SA); 3) 50% chopped timothy hay + 47.6% rolled barley and 2.4% soya supplement (HC); 4) HC + SA. Feed was offered every 2 h. A sample of whole rumen contents (liquid and solid) was collected 1 h after the 07:00 h feeding to isolate the bacteria associated with the liquid phase (BAL) and the bacteria adherent to the solid phase (BAS). Organic matter (OM) content of BAS was greater (P ≤ 0.0001) than that of BAL, independently of the type of diet fed and of the presence or absence of the pro-biotic mixture. Oppositely, total nitrogen content (N), expressed as g 100 g−1 OM, was greater (P ≤ 0.0001) in the BAL fraction than in the BAS fraction, the difference in N between the two bacterial fractions being more pronounced with the HF diet (P ≤ 0.05). Organic matter content in both bacterial fractions was greater (P ≤ 0.05) when heifers were fed the HC diet. Addition of probiotic had no effect on OM or N content of each bacterial fraction. Significant differences between amino acid composition of BAL and BAS were observed for 10 out of 16 amino acids studied. For most amino acids, differences in content observed between BAL and BAS were maintained independently of the probiotic supplementation whereas diet affected the relative composition of the bacterial fractions for five amino acids. Finally, addition of probiotics did not affect molar proportions of ruminal volatile fatty acids, which were affected by the diet. Key words: Rumen bacteria, chemical composition, probiotic, amino acid
Prediction of nutritive value of hay from differential scanning calorimetry measurements on forage and feces
Authors: Mathison G. W. , Sedgwick G. , Fenton T. F. , Walshaw J.
Published: March 2010

Differential scanning calorimetry measurements were conducted with six alfalfa and nine grass hays and corresponding cattle feces. Feces and hays gave different responses. Relatively low correlation coefficients between hay minus fecal response curves and cattle intake and organic matter digestibility measurements indicated that such differences were of little practical value in predicting forage nutritive value. Key words: Differential scanning calorimetry, forage, cattle, feces, digestibility, intake
Apparent energetic efficiency of jejunal glucose uptake in young adult turkeys selected for rapid growth
Authors: Fan Y. K. , Croom Jr W. J. , Christensen V. L. , Bird A. R. , Daniel L. R. , McBride B. W. , Eisen E. J.
Published: March 2010

A rapid growth line (F) and a randombred control line (RBC2) of 16-wk-old unsexed turkeys were used to examine the effect of genetic selection for rapid growth on jejunal O2 consumption, glucose uptake and apparent energetic efficiency of glucose uptake. F line had 85% greater feed-deprived body weight (FBW, kilogram) than RBC2 line (P < 0.001) at 16 wk of age and a lighter (gram/kilogram FBW) and shorter (centimeter/kilogram FBW) small intestine and jejunum (P < 0.001). Additionally, the jejunum was composed of a higher proportion (P < 0.007) of mucosal tissue. There was no difference between the lines in apparent energetic efficiency (nmoles ATP expended/nmoles glucose uptake) of jejunal active glucose uptake. These data suggest selection for rapid growth in turkeys does not result in more efficient glucose uptake from the jejunum. Key words: Genetic selection, small intestine, glucose uptake, respiration, turkey
Age-regulated expression of genetic and environmental variation in fitness traits. 2. Genetic effects and variances for viability among crosses from a factorial mating of six selected Leghorn strains
Authors: Fairfull R. W. , Liljedahl L.-E. , Gowe R. S.
Published: March 2010

White Leghorn strains were crossed reciprocally in a complete factorial mating producing 6 pure strains and 30 strain-crosses, which were kept for two laying cycles: 133–496 d of age and 547–909 d. Hens were housed for lay individually in four two-tiered batteries of cages. Strain additive effects (Ai), strain sex-linked effects (Zi), strain-cross heterotic effects (hij) and residual effects were calculated using regression. Viability was high in the first cycle of egg production with only 1 to 3% mortality in each of the four 11-wk periods, but lower in the second cycle decreasing with age. There was significant variation among strains in additive autosomal and sex-linked genetic effects and strain-cross heterotic effects, which increased with age in the second cycle. Heterosis for viability was positive in some strain-crosses and negative in others with considerable changes with age. The magnitude of heterotic effects was generally greater than the magnitude of additive or sex-linked genetic effects for viability. These results imply that different genotypes mount subtly different genetic responses to the problems of viability with advancing age and that more than one theory of ageing could apply. The results are discussed in relation to the theoretical aspects of ageing genetics. Key words: Ageing, fitness, viability, genetic effects, genetic variation, environmental variation
Mineral composition of oil-free seeds of Brassica napus, B. rapa and B. juncea as affected by location and year
Authors: Bell J. M. , Rakow G. , Downey R. K.
Published: March 2010

Three cultivars of Brassica (Westar, Brassica napus; Tobin, B. rapa; Cutlass, B. juncea) were grown in four locations in 4 successive years, with duplicate samples taken from each treatment. Harvested seed was hexane-extracted, ground and analyzed for mineral content. The average contents (mg kg−1) were: Ca, 0.64; P, 1.12; Mg, 0.56%; Cu, 6.2; Zn, 46; Fe, 188; and Mn, 55. Values for Westar and Tobin were generally similar but Cutlass contained less Ca, Mg, Fe and Mn and more Cu and Zn (P < 0.01). Locations affected all mineral levels. One location produced samples lower in Ca, P, Cu and Mn but higher in Zn than the other locations (P < 0.01). Year-to-year variability was of minor consequence. Key words: Brassica napus, Brassica rapa, Brassica juncea, mineral, seed
Effects of mechanical treatment of whole canola seeds on performance, diet digestibility and rumen parameters of lambs fed grass silage
Authors: Huard S. , Petit H. V. , Seoane J. R. , Rioux R.
Published: March 2010

Thirty-three lambs (25.2 ± 2.7 kg body weight) were used to determine if mechanical treatment of canola seed could improve the performance of growing lambs and diet digestibility. All lambs received a basal diet of 179 g d−1 of a 16% crude protein (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. Dry matter intake was similar for all diets. Average daily gain (ADG) was 20% lower (P < 0.001) for lambs fed whole or crushed canola seeds than for those fed the C diet. Lambs fed GCS had intermediate ADG between those fed C and those fed WCS and RCS diets. In general, apparent digestibility of C was higher (P < 0.01) than that of WCS and RCS and digestibility of GCS was intermediate. Rumen pH and molar proportions of individual volatile fatty acids (VFA) were not affected by treatments. Rumen ammonia-N concentration was similar among treatments. Utilization of whole canola seeds as a protein and energy supplement to grass silage resulted in lower performance of lambs compared to that obtained with a mixture of canola meal and canola oil. Key words: Canola seeds, silage, lamb growth
Phytase and cholecalciferol supplementation of low-calcium and low-phosphorus diets for pigs
Authors: Adeola O. , Orban J. I. , Ragland D. , Cline T. R. , Sutton A. L.
Published: March 2010

The effects of different levels of calcium, phytase, and cholecalciferol in low-phosphorus diets were studied in individually-penned 20-kg pigs for 28 d. The positive control diet, used in all three experiments, was formulated to contain 6 g Ca and 5.4 g P kg−1. In the first experiment, four barrows and four gilts received one of seven diets arranged as a positive control plus 2 × 3 factorial of phytase (0 or 1, 600 units kg−1) and calcium (3, 4.5 or 6 g kg−1) containing phosphorus at 3.4 g kg−1. Phytase addition increased (P < 0.05) plasma phosphorus concentration, weight gain and gain:feed ratio. Plasma phosphorus, weight gain and gain:feed ratio were linearly reduced (P < 0.05) as dietary calcium level increased in the low-phosphorus diets but not in the phytase-supplemented low-phosphorus diets. The second experiment was similar to the first experiment, except that phytase was reduced to 800 units kg−1 and dietary calcium levels were 2.5, 3, or 3.5 g kg−1. Phytase addition increased (P < 0.05) weight gain, gain:feed ratio, plasma phosphorus and calcium. A low-calcium (3.5 g kg−1), low-phosphorus (3.4 g kg−1) diet was supplemented with phytase (0 or 800 units kg−1) and cholecalciferol (0 or 800 ug kg−1) in a 2 × 2 factorial arrangement plus a positive control in the third experiment. Growth performance was similar (P > 0.1) among pigs that received the positive control and the phytase- or cholecalciferol-supplemented low-calcium, low-phosphorus diets. These results demonstrate that high dietary calcium in a low-phosphorus diet depresses pig performance and that phytase or cholecalciferol supplementation of a low-calcium (3.5 g kg−1), low-phosphorus (3.4 g kg−1) diet produces similar growth performance as a diet with adequate calcium (6 g kg−1) and phosphorus (5.4 g kg−1) when fed to 20-kg pigs. Key words: Pigs, phytase, cholecalciferol, phosphorus, calcium
Beef tenderness: within longissimus thoracis et lumborum steak variation as affected by cooking method
Authors: Dugan M. E. R. , Aalhus J. L.
Published: March 2010

The effects of cooking method on beef longissimus thoracis et lumborum (LTL) tenderness and tenderness variation were investigated. Steaks from three tenderness categories (tender: shear force <68.7 N; moderate: 68.7 N < shear force <103 N; tough: shear force >103 N; 8 loins per category) from commercial loins werecooked to an internal temperature of 72 °C using a single-sided grill, a double-sided grill, or a water bath. Shear force was not affected by cooking method or core location. Regressing within-animal shear force SD versus within-animal shear force gave a significant positive correlation (R = 0.76; P < 0.001), indicating that shear force variation increases as toughness increases. Results indicate that more shear force measurements need to be taken for tough versus tender steaks if an equal repeatability of shear prediction is to be made, regardless of cooking method. Key words: Beef, tenderness, variation
Efficacy of tetrachlorvinphos insecticide dust against darkling beetles in commercial broiler chicken barns
Authors: Khan B. A. , Day P. A. , Goonewardene L. A. , Zuidhof M. J. , Hawkins G.
Published: March 2010

Residual application of tetrachlorvinphos dust (Debantic 50WP) was evaluated against darkling beetles in commercial broiler chicken barns. The dust formulation was applied using an electrostatic duster after clean out of old litter at the start of a new broiler cycle. Tetrachlorvinphos dust provided adequate control of beetle larvae and adults up to 5 wk. One time of application is adequate for one commercial broiler chicken production cycle only. Key words: Darkling beetle, Alphitobius diaperinus,tetrachlorvinphos, chicken, electrostatic duster
Influence of post-calving supplemental protein on calf performance and reproductive efficiency for beef cows fed silage
Authors: Charmley E. , Small J. A. , McRae K. B.
Published: March 2010

Protein supplementation for winter-calving beef cows between calving and turnout to pasture was studied in two trials. Changes in cow body weight (BW) and condition and calf BW gains were recorded from calving to weaning in the fall. Reproductive performance was monitored, and in trial 2, milk production was determined. In trial 1, multiparous silage-fed cows were allocated to one of five levels of corn gluten meal (CGM): 0, 200, 400, 600 and 800 g d−1. In the second trial, cows were allocated to either restricted or ad libitum silage feeding in combination with three protein supplements: no protein, 400 g d−1 CGM or 475 g d−1 soybean meal (SBM). In trial 1, cows gained weight during supplementation, but on pasture they lost weight (linear effect, P = 0.10). Calf gains and weights at turnout and weaning showed a quadratic response to protein supplementation (P < 0.05). There was a trend toward a linear decline in days to first service with increasing levels of CGM (P < 0.10). In trial 2, cows on restricted silage feeding lost weight (P < 0.05) and body condition (P < 0.10), whereas those fed ad libitum silage gained weight and condition. On pasture, this pattern of weight change was reversed (P < 0.05). Protein supplementation did not influence BW change but tended to cause a lower body condition score at turnout (P = 0.10). Restricting silage intake to the cow did not affect calf performance, but protein supplementation increased gains both during supplementation and on pasture, thus increasing weaning weights (P < 0.05). When silage was fed ad libitum, SBM was more effective than CGM for increasing calf gain. However, when silage was restricted, CGM was more effective. Restricting silage intake did not impair milk production, but feeding CGM increased milk production (P < 0.05). For ad libitum-fed cows, protein supplementation increased pregnancy rate; restricting feed had the opposite effect. Our data suggest that protein supplementation to silage-fed beef cows in good body condition can increase calf performance; however, the level of supplementation is critical, and possible adverse effects on breeding have to be taken into account, particularly with cows in negative energy balance after calving. Key words: Beef cow, protein, milk production, calf gains, silage
Effect of sainfoin on in vitro digestion of fresh alfalfa and bloat in steers
Authors: McMahon L. R. , Majak W. , McAllister T. A. , Hall J. W. , Jones G. A. , Popp J. D. , Cheng K.-J.
Published: March 2010

The effects of sainfoin (Onobrychis viciifolia) on digestion of alfalfa (Medicago sativa) were investigated in vitro and in vivo. Fresh alfalfa and sainfoin were incubated in an artificial rumen (Rusitec) in ratios of 100:0, 75:25, 50:50, 25:75 and 0:100 (as-fed). Disappearances of dry matter and N from sainfoin were 77 and 65% of those from alfalfa, respectively. Protease and endoglucanase activities, NH3-N and methane production declined (P < 0.05) as sainfoin increased. Bacterial numbers and microbial outputs were unchanged (P > 0.05), but cells incorporated more 15NH3N as sainfoin in the diet increased. Chopped leaves (100:0, 95:5 and 90:10 alfalfa:sainfoin) were incubated for 48 h with diluted ruminal fluid containing 0 or 50 mg polyethylene glycol, which binds tannins. Gas and volatile fatty acid productions were similar (P > 0.05) across treatments, but including 10% sainfoin (without polyethylene glycol) reduced (P < 0.05) NH3 concentrations between 8 and 24 h. Sainfoin tannins reduced degradation of forage protein without affecting the digestibility of the nonprotein fraction. Alfalfa herbage was fed alone or with early- to full-bloom sainfoin herbage (at 10 or 20% of ad libitum alfalfa dry matter intake) or with sainfoin hay or pellets, to eight Jersey steers in crossover trials conducted over 4 yr. Including sainfoin in the diet reduced (P < 0.001) the incidence of bloat by 45 to 93% in 3 of 4 yr, irrespective of the form in which it was supplied. Co-feeding sainfoin can markedly reduce the incidence of bloat in ruminants consuming fresh alfalfa. Key words: Alfalfa, sainfoin, bloat, condensed tannins
Methane suppression by coconut oil and associated effects on nutrient and energy balance in sheep
Authors: Machmüller A. , Kreuzer M.
Published: March 2010

Three different diets with increasing proportions of coconut oil (0, 3.5 and 7%) were fed to six sheep in an incomplete Latin square experiment with four replicates per diet. The diets were composed of hay and concentrates either without or with coconut oil. Concentrate comprised 28.8 and 54.6% of the diet DM in the treatments containing 3.5 and 7% coconut oil, respectively. Wethers on all treatments were fed at 1.2 × maintenance. Gaseous exchange was measured in respiratory chambers. Protozoa counts were reduced (P < 0.05) by 88 and 97% when diets contained 3.5 and 7% coconut oil, respectively, whereas bacteria counts increased (P < 0.05). Supplementation of coconut oil at proportions of 3.5 and 7% suppressed (P < 0.001) methane production by 28 and 73%, respectively, as related to the unsupplemented diet. This proportionately reduced (P < 0.001) the amount of gross energy lost through methane from 7.5 to 5.7 and 2.5%, in diets containing 0, 3.5 and 7% coconut oil, respectively. Assuming a linear suppressive effect of coconut oil, about half of the additional methane reduction with the 7% coconut oil diet as compared with the 3.5% diet was attributed to the substitution of concentrate for hay. Digestibility of cell wall constituents was numerically decreased by coconut oil. Apart from this and its effect on methane emissions coconut oil had no major influence on digestion or on energy and nitrogen balance. Key words: Coconut oil, methane, energy balance, sheep, ruminants
Cellular and molecular approaches for altering muscle growth and development
Authors: Grant A. L. , Gerrard D. E.
Published: March 2010

Understanding the cellular and molecular processes involved in the development of muscle is necessary to develop new strategies for improving the efficiency of meat-animal production. The objectives of this paper are to review some of the processes of muscle development important to meat animal production, including meat quality, and to identify potential cellular and molecular biological approaches to alter these developmental processes. Some of the processes by which muscle develops can be exploited in order to develop in vivo models for further study of muscle growth. Cell-mediated gene transfer and direct DNA injection are among the many techniques that can be used to develop in vivo animal models, and these models can be developed in meat-producing species. Many of these models will undoubtedly lead to the development of strategies to enhance meat-animal production. Key words: Myogenesis, gene transfer, DNA, muscle fiber, meat quality
Molecular techniques used in the search for genetic determinants to improve meat quality
Authors: Meadus W. Jon
Published: March 2010

An objective of the red meat industry is to improve the eating qualities of their product. This article focuses on some of the newer techniques used in identifying the genetic factors controlling the eating qualities of red meat animals. Identifying genes in an animal can be achieved either directly, or by linking with genetic markers. Linking a trait with genetic markers has become much easier with the recent development of microsatellite DNA-based genomic maps. The ultimate goal of most molecular biologists is to identify the DNA sequence that defines a unique genetic variant. If the actual sequence mutation is known, animals can be conclusively genotyped without pedigree information. Using microsatellite mapping, genetic variants can be defined in a range of DNA of approximately 100 to 1000 kilobases, which can include more the 50 to 100 genes. Current methods available for identifying specific genetic mutations can analyze approximately 0.4 to 2 kilobases per reaction, but a gene can be more than 60 kilobases long. To conclude, gene mapping can fix a genetic trait quickly, which is useful in controlled breeding programs, but the next step of identifying the genetic variants is very difficult. However, if a trait is defined biochemically, alternative molecular techniques can be applied to a few candidate genes, which might be a riskier approach, but it can give the best result of a simple genetic test. These tests can then be applied to identify and design meat animals according to specific food markets. Key words: Meat quality, gene mapping, genetic testing
The effects of methionine supplementation upon milk composition and production of forage-fed dairy cows
Authors: Pacheco-Rios D. , McNabb W. C. , Hill J. P. , Barry T. N. , Mackenzie D. D. S.
Published: March 2010

Two experiments (mid- and late lactation) were conducted to test whether methionine (Met) limited milk production in Friesian cows fed sole diets of fresh perennial ryegrass–white clover pasture. In mid-lactation (exp. 1), 26 cows were assigned to one of three treatments: ruminally protected oral DL-Met (15 g d−1), continuous intrajugular infusion of L-Met (15 g d–1) and control. Twelve animals from exp. 1 were used during late lactation (exp. 2) and distributed in two experimental groups: ruminally protected oral DL-Met (15 g d−1) and control. Dry matter, metabolizable energy, crude protein and Met intakes, milk yield and composition and blood Met, cysteine and urea were measured. Oral and intravenous Met supplementation increased blood Met concentration by 50–90% compared with controls. Met supplementation did not alter the concentration of milk fat, protein or lactose in either experiment. Met supplementation had no significant effects on yields of fat, lactose, casein, whey proteins or non-protein nitrogen during mid-lactation. In late lactation, Met supplementation did not affect milk protein composition or yield of milk components, with exception of a decrease (P < 0.05) in the yield of β -casein. Intravenous Met supplementation increased (P < 0.05) the efficiency of conversion of pasture N to milk protein in mid-lactation. Key words: Dairy cows, methionine, ruminally protected methionine, milk protein, casein, fresh pasture diets
Effects of dietary chromium-yeast in weaning-stressed piglets
Authors: Baldi A. , Bontempo V. , Dell'Orto V. , Cheli F. , Fantuz F. , Savoini G.
Published: March 2010

The aim of this study was to evaluate the effects of Cr supplementation (as Cr-yeast) on growth performance, some blood parameters and neutrophils superoxide anion production, in weaning-stressed piglets. Thirteen crossbred (Landrace × Large White) litters were assigned to Cr-supplemented prestarter diet for 21 d (from 10 d after birth to 7 d post-weaning). Thirteen other litters, forming the control group, were not given supplemental Cr. Blood samples were taken on day 3 post-weaning and 1 h after litters were moved to the post-weaning facilities (day 7 post-weaning). To enhance stress response, ACTH (5 µ g kg−1 BW) was given to some animals immediately before moving. Cromium supplementation did not improve piglet weight or superoxide production by neutrophils. The plasma concentration of non-esterified fatty acids was higher (P < 0.05) and glucose concentration was lower (P < 0.05) at 7 d post-weaning compared with 3 d in both treated and control piglets. In ACTH-challenged piglets, a further lowering of blood glucose was associated with Cr supplementation (P < 0.05), but cortisol and insulin levels were not affected by dietary treatment. These data suggest that Cr supplementation does not reduce weaning stress in piglets. However, in high-stress conditions (as simulated by ACTH challenge) Cr supplementation may improve peripheral glucose utilisation. Key words: Chromium supplement, piglet, blood parameters, weaning stress
Autonomic regulation of plasma insulin, glucagon and growth hormone responses to feeding in sheep fed a diet supplemented with calcium propionate
Authors: Sano H. , Mori Y. , Takahashi H. , Terashima Y.
Published: March 2010

The role of the autonomic nervous system in the regulation of plasma insulin, glucagon and growth hormone (GH) responses to supplemental propionate was investigated in rams. The rams were fed alfalfa hay cubes supplemented with 10 mmol kg−1 d−1 of calcium propionate. Saline, phentolamine, propranolol, atropine or hexamethonium were separately infused for 135 min starting 15 min before feeding. During saline infusion, the concentrations of plasma insulin and glucagon increased (P < 0.05) after the initiation of feeding, whereas plasma GH concentrations tended to decrease. Plasma insulin responses to feeding tended to be reduced by atropine and hexamethonium infusions. Plasma glucagon responses were abolished by atropine, hexamethonium and phentolamine infusions. It is suggested that in rams fed a propionate supplemented diet, the release of insulin and glucagon increases in response to feeding. Insulin release is mediated by activation of the parasympathetic nervous system, although responses were not significant in this study, while glucagon release is mediated both by activation of the parasympathetic nervous system and by the adrenergic α-receptors of the sympathetic nervous system. This study does not support a role for the autonomic nervous system in the regulation of GH release. Key words: Autonomic nervous system, insulin, glucagon, growth hormone, propionate, sheep
Variability of apparent ileal amino acid digestibility in different pea samples for growing-finishing pigs
Authors: Fan M. Z. , Sauer W. C.
Published: March 2010

Six barrows, average initial body weight 32.5 kg, fitted with a simple T-can-nula at the distal ileum, were used to investigate factors responsible for the variability of apparent ileal amino acid (AA) digestibility values among six pea samples. The barrows were fed six corn-starch-based diets, formulated to contain 16.5% crude protein (CP) (as-fed) from six different pea samples, according to a 6 × 6 Latin square design. Chromic oxide (0.3%) was used as the digestibility marker. The pigs were fed twice daily, at 0800 and 2000 h. The dietary allowance was 1600 g−1. Each experimental period lasted 7 d. Ileal digesta were collected at 2-h intervals for a total of 24 h from 0800 h on day 6 to 0800 h on day 8. With the exception of arginine, cysteine, histidine, and methionine, there were differences (P < 0.05) in the apparent ileal digestibility values of the indispensable including semi-essential (+semi-) AA among the pea samples. Of the indispensable AA (+semi-) within each pea sample, the digestibility values of arginine and lysine were relatively high, ranging from 88.3 to 91.3% and from 78.7 to 85.2%, respectively, while the digestibility values of cysteine, methionine, and tryptophan were relatively low, ranging from 53.8 to 62.7%, from 69.4 to 75.4%, and from 53.1 to 70.4%, respectively. With the exception of arginine, cysteine, and tryptophan, the ileal digestibility values of the indispensable AA (+semi-) were negatively correlated (P < 0.05) with the neu-tral-detergent fiber content in the pea samples. Of all the AA, only the digestibility of tryptophan was negatively correlated (P < 0.05) with the trypsin inhibitor activity in the pea samples. The significant finding of this study was that with the exception of arginine, cysteine, and proline, differences in the digestibility values of all other AA in the pea samples were positively correlated (P < 0.05) with their respective dietary AA contents. This suggests that differences in AA levels in the assay diets were responsible for the variability of apparent ileal digestibility values of AA between pea samples. Therefore, to eliminate this methodological effect, true rather than apparent ileal AA digestibility values for peas should be determined. Key words: Amino acids, ileal digestibility, peas, pigs
Using plant cuticular alkanes to study plant-animal interactions on pastures
Authors: Chen W. , Scott J. M. , Blair G. J. , Lefroy R. D. B.
Published: March 2010

Two experiments were conducted to validate an approach of using plant cuticular alkanes to estimate diet composition and fecal output. In the first experiment, n-alkane patterns of the four major pasture species were determined and compared and a further two sets of pasture mixtures were prepared to validate the use of plant n-alkane patterns to estimate species composition. In the second experiment, estimates of daily fecal output of grazing sheep were compared using controlled-released devices containing either Cr2O3 or alkanes. There were considerable differences in odd-numbered alkanes and in their total content between species. Results from the first experiment, where two sets of pasture mixtures were analyzed suggest that it is feasible to separate species composition using differences in n-alkane pattern. The second experiment showed that accurate estimation of daily fecal output can also be obtained using capsules containing alkanes. Key words: n-alkane, pasture, diet composition, fecal output