bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of dietary sunflower oil and vitamin E on Beef cattle performance, carcass characteristics and meat quality
Authors: Mir P. S. , McAllister T. A. , Zaman S. , Morgan Jones S. D. , He M. L. , Aalhus J. L. , Jeremiah L. E. , Goonewardene L. A. , Weselake R. J. , Mir Z.
Published: April 2011

In the present study, we tested the hypothesis that feeding sunflower oil (SFO) containing about 70% linoleic acid would increase conjugated linoleic acids (CLA) content of beef and that the increased CLA levels would improve meat shelf life. Two feeding trials were conducted to determine the effect of SFO supplementation on beef production , carcass characteristics and meat quality parameters. In addition, the visual aspects of beef quality in retail display as influenced by dietary vitamin E were compared with that of the increased CLA derived from dietary SFO. In exp. 1, 72 finishing steers (465 ± 9 kg) were individually fed one of four dietary treatments: an unsupplemented control finishing diet, the control diet supplemented with 6% SFO, 500 IU head-1 d-1 vitamin E or a combination of 6% SFO and 500 IU head-1 d-1 vitamin E for 95 d. Data from in vitro gas production from the diets indicated that oil inclusion reduced rate and lag time prior to initiation of gas production. Dry matter intake (DMI) declined (P < 0.05) due to dietary treatments without affecting average daily gain or feed conversion efficiency. Meat from steers fed all supplements was less red, more discolored and less acceptable after 2 d storage in a display case. In exp. 2, 40 steers (412.5 ± 11 kg), in individual pens, were used in a second completely randomized design experiment to evaluate the effect of supplementation of steam-rolled barley based finishing diets with 0, (CON) 3 or 6% SFO or 500 IU head-1 d-1 vitamin E on performance, carcass, meat characteristics, and fatty acid composition of beef. No difference (P > 0.05) in final liveweight, DMI, average daily weight gain (ADG) and feed efficiency (FE) of steers fed diets was found. Carcass grade fat was higher (P < 0.05) in steers fed the 6% SFO diet than the other diets. Retail acceptance score of meat obtained from steers fed 6% SFO was higher than from steers fed other diets (P < 0.05). In both experiments, the fatty acid composition of the meat indicated that C16:0 and C16:1 fatty acid levels were lower (P < 0.05) while C18:2 was higher (P < 0.05) in longissimus muscle of steers fed 6% SFO than the other diets. CLA content in fat from longissimus muscle was higher in steers fed the 6% SFO than control diets (3.5 vs. 3.0 mg g-1 in exp. 1 and 3.5 vs. 2.0 mg g-1 in exp. 2; P < 0.05). Hence supplementing feedlot diets with SFO for up to 108 d can increase CLA composition of beef. Positional distribution of fatty acids indicated that the majority of the CLA was in the sn-2 position of the triacyglycerol molecule. Key words: Beef cattle, conjugated linoleic acid, fatty acids, meat quality, sunflower oil, vitamin E
Cattle herbage utilization patterns under high-density rotational grazing in the Aspen Parkland
Authors: Asamoah S. A. , Bork E. W. , Irving B. D. , Price M. A. , Hudson R. J.
Published: April 2011

Native Aspen Parkland landscapes consist of a complex mosaic of plant communities, including riparian meadows, upland grasslands, and forests. Sustainable livestock production in this environment depends on an understanding of livestock grazing behavior among communities, particularly under contemporary, intensive management rotational grazing systems. This study examined seasonal patterns of absolute (kg ha-1) and relative (%) herbage utilization, as well as plant community visitation, across a Parkland landscape by 150 heifers in two rotations of a high-intensity, low-frequency grazing system. Graminoids constituted more than 92% of the total herbage utilized. Absolute graminoid utilization within each grazing period was greater (P < 0.05) throughout the growing season from riparian meadows (2003 to 2114 kg ha-1) than from upland grasslands (762 to 1041 kg ha-1) or forests (782 to 800 kg ha-1). In contrast, relative graminoid utilization remained similar (P > 0.05) among communities in either rotation, suggesting heifers grazed in proportion to graminoid availability (57–61% in first rotation, 44–54% in second rotation). Although riparian meadows represented a small fraction of the landscape (~ 4%), and provided up to 9.5% of the total forage used, the majority of herbage removal at the paddock level continued to originate from upland grasslands and forests. Patterns of visitation indicated heifers initially visited riparian meadows more often within each 3–4 day grazing period, regardless of entry date. While upland grasslands were least visited in June, forests were least visited in August. Based on these utilization and visitation patterns, we discuss the implications of using high-density, rotational livestock grazing for the sustainable management of Aspen Parkland rangelands. Key words: Aspen forest, cattle grazing, forage quality, herbage utilization, riparian meadow, rotational grazing, upland grassland
Effect of dietary leucine level on growth performance, and carcass and meat quality in finishing pigs
Authors: Hyun Y. , Ellis M. , McKeith F. K. , Baker D. H.
Published: April 2011

The effect of feeding corn-soybean meal-based diets with two levels of supplemental leucine (0 vs. 2%) on growth, carcass, and pork quality characteristics was evaluated in 40 individually fed finishing pigs over a 39-d feeding period (78.4 ± 3.46 to 114.8 ± 7.30 kg liveweight). Supplemental dietary leucine reduced weight gain (8.7%; P < 0.05), but had no effect (P > 0.05) on feed intake or gain:feed ratio. Feeding diets with 2% supplemental leucine increased (P < 0.05) longissimus fat content and marbling scores in both barrows and gilts. Key words: Finishing pigs, dietary leucine, intramuscular fat
Phosphorus digestibility in low-phytate barley fed to finishing pigs
Authors: Thacker P. A. , Rossnagel B. G. , Raboy V.
Published: April 2011

Twenty-four crossbred barrows (Camborough 15 Line female × Canabred sire) weighing an average of 51.3 ± 5.1 kg were used in a trial conducted during two periods according to a completely randomized block design. The pigs were assigned to one of six dietary treatments comprised of a normal two-rowed, hulled variety of barley (CDC Bold) or three low-phytate genotypes selected to contain approximately 68, 41 or 3% of the normal level of phytate. A normal hulless barley (CDC Dawn) and a hulless genotype selected to contain 54% of the normal phytate content were also included. The diets fed contained 99.5% barley and 0.5% chromic oxide. The marked feed was provided for a 7-d acclimatization period, followed by a 3-d fecal collection. At the conclusion of the first replicate, the pigs were assigned to different treatments and the procedure was repeated resulting in eight observations per treatment. Selection for phytate content had no effects on the apparent fecal digestibility of dry matter, crude protein or gross energy (P > 0.05). The digestibility coefficients for dry matter and energy were significantly higher for the hulless varieties of barley than the hulled genotypes. Phosphorus digestibility increased as the level of phytate in the barley declined. The linear relationship relating phosphorus digestibility (y) to phytate content (x) was: y = 67.7 − 12.54x       (r2= 0.64; P < 0.0001).
Defining the effects of wheat type, water inclusion level, and wet-diet restriction on variability in performance of broilers fed wheat-based diets with added water
Authors: Scott T. A. , Silversides F. G.
Published: April 2011

The objectives of the study were to determine if feed conversion ratio (FCR) in broilers fed wet Hard Red Spring (HRS) as compared to Durum-based wheat diets could be reduced by: (a) diluting HRS with Durum wheat, (b) pelleting of the wheat, (c) adding different levels of water to the diet, or (d) restricting intake of diets to which water was added. Three wheat types [Durum, HRS and a Composite (50:50) sample] were ground, with one portion of the ground grain being pelleted and reground before both forms of each wheat type were included at 80% of a basal broiler diet. All diets were supplemented with a commercial wheat enzyme and fed as a mash. Each of the six diets was fed in one of four feed regimens: DRY (as is); WET1.2 (DRY with 1.2 g water g-1 feed); WET0.6 (DRY with 0.6 g water g-1 feed); and RWET1.2 [WET1.2 diet treatment restricted-fed to 120% of the previous day’s DRY feed intake (on an air-dried basis) for each diet type]. This provided 24 dietary treatments each fed to six cages of five male broilers from 1 to 21 d of age. The wet diets were prepared daily. Among the feed regimens WET1.2 resulted in the significantly highest 21-d body weight. The significant increase in feed intake and FCR of HRS-based diets with added water was reduced significantly by diluting this wheat with Durum wheat. Feeding the unpelleted Composite wheat sample significantly improved growth rate over either wheat alone, presumably due to an improved balance of nutrients. Pelleting significantly reduced intake of wet HRS-based diets and increased apparent metabolisable energy (AME), resulting in a marked reduction in FCR compared to unpelleted diets. There was some value in using less water in HRS-based, but not in Durum-based diets, with respect to FCR and metabolisable energy retention. Physical restrictions of feed intake reduced FCR of wet (WET1.2) unpelleted HRS diets, but did not affect the same diet when wheat was pelleted. Further work is required to establish the optimum consistency of feed in a wet form to maximize feed intake and growth while minimizing FCR. Key words: Wheat, wet feeding, enzymes, feed intake, broilers
Use of CAT scan to determine mammary gland development of sows injected with growth hormone releasing factor during gestation and (or) lactation
Authors: Petitclerc and C. Farmer D.
Published: April 2011

Fifty-two Yorkshire × Landrace gilts were allotted to: (1) saline injections (CTL; n = 17) thrice daily during gestation (day 100 to parturition) and lactation (days 3 to 29); (2) s.c. injections of 12 mg of GRF (1-29)NH2 thrice daily from day 100 of gestation to parturition (GEST; n = 12); (3) s.c. injections of 12 mg of GRF thrice daily from days 3 to 29 of lactation (LACT; n = 11); and (4) s.c. injections of 12 mg of GRF thrice daily during gestation (day 100 to parturition) and lactation (days 3 to 29) (GEST-LACT; n = 12). All sows were slaughtered on day 30 of lactation and mammary glands were excised and stored frozen at -20°C. Mammary development was measured on half of the thawed mammary gland with CAT scanning, and standard dissection and previously published biochemical measurements of mammary development were used to assess the contralateral half; correlation analyses were used to compare the two approaches. Volume of parenchymal tissue of GEST-LACT sows was 19% smaller than that of sows subjected to other treatments (GEST × LACT interaction, P = 0.01). Total mammary gland volume (r = 0.68; P = 0.002) and extraparenchymal tissue volume (r = 0.77; P < 0.001) measured by CAT scanning were correlated with extraparenchymal tissue weight obtained by tissue dissection. However, none of the CAT scan measurements were correlated with parenchymal tissue weight (P > 0.1). In conclusion, exogenous GRF given to sows during lactation affected cell volume/differentiation of the mammary gland. For mammary gland assessment in lactating sows, the CAT scan technique accurately measured the weight and volume of extraparenchymal tissue but not parenchymal tissue mass. Key words: Sows, mammary gland, mammary development, CAT scan, growth hormone-releasing factor, lactation
The complex world of gastrointestinal bacteria
Authors: Anderson K. L.
Published: April 2011

The world of gastrointestinal (GI) bacteria is one of the most complex and intricate of the microbial domain. These bacteria are confronted with a constantly changing (and often hostile) environment, including fluctuations in both physical and chemical conditions. Neighboring microorganisms not only contend for substrate but even launch complex chemical attacks with the apparent purpose of disrupting the activity of their competitors. Yet, some species not only survive, they even flourish, in the GI tract because they possess the ability to adapt to these environmental fluctuations and assaults from other microbes. Such adaptation involves sophisticated programs in the bacterial cell that enable it to monitor its environment and make necessary adjustments of physiological activity and gene expression. Among these adjustments is the ability of cell-to-cell communication, biofilm formation, regulation of cytoplasmic pH, and maintenance of genetic diversity through mutation and horizontal gene transfer. As a consequence, bacteria in the GI tract often manifest very different physiological features than are observed for the same bacteria during routine laboratory cultivation. Key words: Gastrointestinal bacteria, bacteria, gastrointestinal tract, ruminal bacteria, biofilms, quorum-sensing, colonic bacteria
Effects of micronization, tempering, and flaking on the chemical characteristics of wheat and its feeding value for broiler chicks
Authors: Niu Z. Y. , Classen H. L. , Scott T. A.
Published: April 2011

Five experiments were conducted to study the effects of micronizing, tempering and flaking of wheat (cv. Genesis) on the chemical characteristics and its feeding value for broiler chicks. Samples of wheat were micronized (infrared invisible band with wavelengths of 1.8 to 3.4 µ) at 90, 105, and 120°C for 50 s, with or without tempering to 20% moisture, and with or without flaking. Micronization at 120°C produced negative effects on weight gain and feed efficiency (0–18 d). Tempering reduced protein solubility in 0.2% KOH, increased the solubility of dietary fibre, and increased in vivo digesta viscosity and in vitro extract viscosity as well as diet AME. Flaking wheat had no effect on broiler performance in exps. 3 and 4, but decreased growth rate and feed efficiency in exp. 5 despite improved dietary AME. Flaking decreased protein solubility at 120°C but had little effect at lower temperatures. The lowest protein solubility was found in the sample that was tempered, micronized at 120°C, and then flaked. In conclusion, micronization at 90 and 105°C improved the feeding value of wheat for broiler chickens. Tempering and flaking may be beneficial at lower micronization temperatures, but can result in lower nutritional value at higher micronization temperature. Key words: Wheat, micronization, metabolizable energy, broiler
Effects of barley silage particle size and concentrate level on rumen kinetic parameters and fermentation patterns in steers
Authors: Soita H. W. , Christensen D. A. , McKinnon J. J.
Published: April 2011

Four Hereford steers (471 ± 31 kg) fitted with ruminal cannulae were used in a 4 × 4 Latin square design to evaluate the effects and possible interactions between silage particle size and concentrate level on digestion and ruminal fermentation parameters. Diets were designed with two forage to concentrate ratios [low forage, 20:80, high forage, 50:50 on a dry matter (DM) basis], combined with two theoretical chop lengths of barley silage; short (SBS) = 4.7 mm and long (LBS) =18.8 mm. Results showed that steers fed diets with SBS consumed more DM than those fed LBS. An interaction (P < 0.05) between particle size and concentrate level was noted for molar proportion of acetate. At the higher concentrate level, feeding SBS diets reduced the molar proportion of acetate but increased the molar proportion of propionate. An interaction (P < 0.05) between particle size and concentrate level was noted for ruminal pH. When compared to LBS, the daily mean rumen pH was lower (P < 0.05) for steers fed SBS with 80% concentrate but not for those fed the 50% concentrate diet. Ruminal ammonia concentration was higher (P < 0.05) for those steers fed the 50% concentrate diets than for those fed the 80% concentrate diets. With high concentrate levels, SBS greatly reduced (P < 0.05) ammonia concentration. Passage rates for particulate matter and the retention time were decreased (P < 0.05) when SBS was fed. Feeding SBS reduced (P < 0.05) total tract digestibility of dry matter, crude protein (CP) and neutral detergent fiber (NDF) (65.5 vs. 68.5%, 66.5 vs. 73.4% and 39.4 vs. 45.9%), respectively. These results suggest that barley silage with a theoretical cut length of 18.8 mm can promote higher rumen pH, ammonia nitrogen, and reduced particulate passage rates. These changes in rumen fermentation parameters should favor optimum rumen function and digestion when high concentrate diets are fed. Key words: Barley silage, particle size, steers, concentrate level, rumen fermentation
Effects of GRF in early gestation on foetal development in Large White and Genex-Meishan gilts
Authors: Lewis E. , Laforest J. P. , Gariépy C. , Farmer C.
Published: April 2011

The effects of growth hormone-releasing factor (GRF), given in early gestation, on reproductive traits, foetal development and pre-weaning growth of piglets from two breeds were studied. Large White (LW, n = 26) and Genex-Meishan (GM, containing 50% Meishan genes, n = 37) pregnant gilts were divided in two groups: (1) saline injections (n = 33) and, (2) injections of 6.66 µg kg-1 of a GRF analogue (n = 30), given thrice daily from days 18 to 33 of gestation. Jugular blood samples were collected on days 17, 34 and 109 of gestation and were assayed for various hormones and metabolites. Thirty-six gilts were slaughtered on day 110 of gestation and uterine, foetal and placental measurements were obtained. The other 27 gilts farrowed. There was a day × treatment interaction (P < 0.001) for glucose, insulin, free fatty acids (FFA) and insulin-like growth factor I (IGF-I), with values being greater on day 34 in gilts receiving GRF. The increase in insulin concentration was greater in LW- than in GM-treated gilts (P = 0.02). Exogenous GRF increased foetal weight in LW litters only (1.13 ± 0.04 vs. 1.05 ± 0.03 kg; P = 0.04) whereas fat content of carcasses tended to be lower only in foetuses of treated GM gilts (5.3 ± 0.2 vs. 5.8 ± 0.2%; P = 0.1). Weight of the longissimus muscle and its fibre number were not influenced by GRF. Furthermore, growth of piglets to 28 d was not affected by GRF treatment (P > 0.1). In conclusion, GRF given in early gestation seems to have different effects in LW and GM litters, yet it does not alter pre-weaning growth rate. Key words: Molybdenum, molybdenosis, copper, mine tailings, reclamation, animal health
Comparing the Canadian pork lean yields and grading indexes predicted from grading methods based on Destron and Hennessy probe measurements
Authors: Pomar and M. Marcoux C.
Published: April 2011

In Canada, actual grading methods based on Destron (DPG) and Hennessy (HGP) probe measurements were approved in 1994. This study was undertaken to verify if both grading methods predict similar lean yields and grading indexes in actual pork carcasses. Data from the following four databases were used, and included hot carcass weight, and backfat and muscle depths as measured by both probes: 1281 carcasses from the 1992 National Cutout, 495 and 76 carcasses from 1997 and 1998 Fédération des Producteurs de Porc du Québec studies respectively, and 266 from a 1999 Agriculture and Agri-Food Canada study. Probes were inserted alternatively at the Canadian grading site. Grading indexes were assigned from a 1999 official grid. For the four studied databases, the HGP-DPG lean yields were different from zero (P < 0.0001) with values of 0.33, 0.35, 0.36 and 0.18%, chronologically. The HGP-DPG grading indexes were also different from zero with values of 0.51 (P < 0.0001), 0.36 (P < 0.0001) and 0.50 (P < 0.0001), 0.21 (P < 0.09), respectively. The slope between lean yields and indexes were different from one, indicating that the underestimation of lean yields and indexes by the DPG method increased with carcass leanness. Key words: Pork, Hennessy, Destron, probes, lean yield, prediction
Seasonal changes of connective tissue fluorescence in well-aged beef roasts, correcting for fat reflectance and signal source
Authors: Swatland H. J.
Published: April 2011

Thirty well-aged (30.3 ± 4.5 d) rib roasts were evaluated serially from January to August. A dual-channel fibre-optic probe measured fluorescence (F; excitation at 365 nm and emission from 410 to 550 nm) and reflectance (R; 550 nm) on the way-in (WI) and way-out (WO). Anatomical measurements were used to differentiate between signals exterior to the longissimus thoracis (EXLT) and intramuscular signals (INLT). Each roast was probed in eight locations, giving 32 sets of signals (position, WI or WO, EXLT or INLT). F peaks c-1 decreased serially with time, mean r = -0.47, P < 0.01. A ratio (F:R) was used to correct F signals for pseudofluorescence (upper edge of F excitation band-pass reflected from fat). This strengthened (P < 0.001) the mean correlation of F:R peaks cm-1 with time to r = -0.59, P < 0.001. F:R peaks cm-1 in EXLT and INLT were correlated, r = 0.24 for WI and r = 0.57 for WO, showing development of extramuscular and intramuscular connective tissues was linked ( P < 0.0005, n = 480). Key words: Beef, connective tissue, fluorescence, seasonal effect
In-cage sandbox as a ground substitute for farmed blue foxes (Alopex lagopus): Effects on digging activity and welfare
Authors: Korhonen H. T. , Jauhiainen L. , Rekilä T.
Published: April 2011

A study on the behavioural and welfare effects of in-cage sandboxes was carried out on juvenile farm-bred blue foxes (Alopex lagopus) with special reference to digging behaviours and time spent on sand substrate. Twelve juvenile male blue foxes were used in each of two experimental groups: (1) a test group and (2) a control group. Animals were raised singly in cages measuring 120 cm long × 105 cm wide × 70 cm high, from weaning in July to pelting in December. All experimental animals were housed conventionally but cages of the test group contained in-cage sandboxes (80 cm long × 40 cm wide × 14 cm high). Various physiological, behavioural, health and production related variables were measured during the study. Final body weights of test animals were significantly (P = 0.05) lower than controls. Occurrence of endoparasites (Toxascaris leonina, Isospora sp.) did not substantially differ between groups. Open field activity was greater (P = 0.02) and latency to touch novel objects shorter (P = 0.02) in the test group compared with the control. Cortisol-creatinine ratio, incidence of stereotypes, size of adrenals or other organs, blood screen and fur quality parameters were not significantly different. Sandbox hygiene deteriorated rapidly during the experimental period. Fur coats of test animals were dirtier than those of controls at pelting. Claw length of test animals was significantly shorter (front foot; P < 0.005, back foot, P < 0.001) than in controls only in October. Altogether nine different sandbox behaviours were observed in the test foxes. Digging was the fifth most common behavior, comprising 5.8% of total sandbox use. Amount of time spent in the sandbox peaked in July, averaging 117 min/24 h, and declined towards winter. The most common sandbox behaviours observed were walking (24.3% of total time), sitting (22.0%) and resting (17.5%). Results indicated low motivation to use in-cage sandboxes as a digging substrate. On the other hand, the presence of in-cage sandboxes may provide opportunities for foxes to engage in other species-specific activities and/or seek sensory comfort through contact with the sand. The effects of in-cage sandboxes on animal welfare need further study. Key words: Alopex lagopus, sand floor, digging, motivation, welfare, fur farming
Variability of thirteen microsatellite markers in American mink (Mustela vison)
Authors: Vincent I. R. , Farid A. , Otieno C. J.
Published: April 2011

A mink genomic library was screened with an (AC)15 oligonucleotide as the probe. Thirteen microsatellite loci were identified and primer sequences and amplification conditions were determined. All the 13 loci were polymorphic in black, brown, pastel and wild mink (n = 86), generating between 4 to 12 alleles per locus. Six of the primer pairs revealed polymorphisms in American pine marten. Key words: Mink, pine marten, microsatellite, polymorphism, polymerase chain reaction, primers
Influence of canola oil on the fatty acid profile in goats’ milk
Authors: Okine E. K. , Goonewardene L. A. , Mir Z. , Mir P. , Wang Z. , Chanmugam P. S.
Published: April 2011

Four Alpine does were used in a 4 × 4 Latin square design to determine the effects of feeding canola oil at four levels: 0, 2, 4 and 6% on milk fatty acid profile. The sum of C12:0 + C14:0 + C16:0 (hypercholesterolemic fatty acids) decreased linearly and C18:0 + C18:1: C16:0 (indicator of cholesterolemic tendency of fat source) increased linearly (P < 0.01) with increased canola oil intake. Key words: Goat, milk, fatty acids, canola oil
Daily variation in the udder surface temperature of dairy cows measured by infrared thermography: Potential for mastitis detection
Authors: Berry R. J. , Kennedy A. D. , Scott S. L. , Kyle B. L. , Schaefer A. L.
Published: April 2011

The daily and within-day variation in udder temperature was monitored in dairy cows (n = 10) using infrared thermography (IRT). The initial assessment and prediction of udder surface temperature variation would hopefully form the basis for future development of an early detection method for mastitis. Our initial objective was to determine the magnitude and pattern of udder temperature variation. To accomplish this, we measured daily fluctuations in udder temperature and the influence of environmental factors upon these values in non-mastitic cows. Udder temperature rose significantly after an exercise period (P < 0.05). Within-day monitoring of udder temperature demonstrated there was a distinct circadian rhythm. Lag regression analysis showed that previous daily udder temperatures together with environmental temperature parameters could successfully predict current udder temperature with a high degree of accuracy. The variation between predicted and actual udder temperature was within the detectable range for an inflammatory response. Infrared thermography shows promise in its application if coupled with environmental temperature monitoring as an early detection method for mastitis. Key words: Thermography, dairy cattle, environment, temperature
Effect of aminophylline on metabolic and thermoregulatory responses during hypothermia associated with cold exposure in lambs
Authors: Zimmermann B. , Diebold G. , Galbraith J. , Whitmore W. , Okamoto M. , Robinson J. B. , Young B. A. , Murdoch G. , Mosenthin R. , Christopherson R. J.
Published: April 2011

Three experiments were conducted with lambs to test the hypothesis that the phosphodiesterase inhibitor/adenosine blocker, aminophylline would enhance metabolic rate and delay the development of hypothermia. In exp. 1, eight lambs were treated either with aminophylline or control (0.9% saline) injections. During hypothermia, metabolic rate was increased from a resting value of 4.8 W kg-1 to maximum values of 15–16 W kg-1. The rate of development of hypothermia and recovery there from were inversely related to age and body weight. Aminophylline (8 mg kg-1) did not affect resting or maximum metabolic rate, but after a second injection, aminophylline increased metabolic rate after warming (P < 0.05) and tended to shorten the absolute period of time to restore normal rectal temperature (P < 0.10). In exp. 2, a dose-response trial with six lambs each receiving 0, 2, 16 or 32 mg aminophylline indicated that dose rates of 16 and 32 mg kg-1 increased (P < 0.05) metabolic rate of lambs. In exp. 3, 21 lambs received either 0.9% saline or aminophylline (24 mg kg-1) injections. Mean heat production ranged from 13 to 15 W kg-1 and was increased approximately 7% (P < 0.01) by aminophylline. Aminophylline, therefore, has some potential as a treatment for hypothermia or to improve recovery from hypothermia in lambs by increasing metabolic rate during cold stress. Key words: Lamb, metabolic rate, hypothermia, thermoregulation, Aminophylline®, phosphodiesterase inhibitor
Biotechnologies of reproduction applied to dairy cattle production: Embryo transfer and IVF
Authors: Bousquet D. , Burnside E. B. , Van Doormaal B. J.
Published: April 2011

The objective of this paper is to review the utilization and outcome of reproductive biotechnologies in dairy cattle. Embryo transfer and IVF have their respective limits that influence their impact on a genetic improvement program. Embryo transfer is efficient and profitable in an artificial insemination breeding and selection program and IVF has great potential. Development of markers highly correlated with various economic traits will progressively be added to the present schemes to make them even more powerful. Key words: Reproductive technologies, embryo transfer, IVF, dairy cows, genetic
Estimates of genetic parameters for ultrasound-measured carcass traits in sheep
Authors: Fernandes T. L. , Wilton J. W. , Tosh J. J.
Published: April 2011

Data on ultrasound traits (loin depth, average backfat thickness, and loin width) were collected from lambs (n = 3483) across Ontario, born between 1997 and 1999. The data were analysed with a REML procedure in a multiple-trait mixed-animal model to obtain (co)variance component estimates. Analyses of all traits included the additive genetic effect of the lamb, sex of the lamb, contemporary group, and breed group effects. Weight or age was included as a covariate in two separate analyses. Estimates of direct additive heritabilities for loin depth, average backfat thickness, and loin width were 0.29, 0.29 and 0.26 respectively, with genetic correlations of -0.17 between loin depth and average backfat thickness, 0.43 between loin depth and loin width, and 0.23 between loin width and average backfat thickness for the weight constant analysis. When the data were analysed using age in the regression analysis, corresponding estimates of direct additive heritabilities were 0.38, 0.35 and 0.30, and genetic correlations between traits were all positive, 0.29 between loin depth and average backfat thickness, 0.61 between loin depth and loin width, and 0.44 between loin width and average backfat thickness. Results indicate that it is possible to make genetic improvement if selection is based on ultrasound information. Key words: Sheep, genetic parameters, heritability, ultrasound
Management strategies to improve cow-calf productivity on meadow bromegrass pastures
Authors: Kopp J. C. , Wittenberg K. M. , McCaughey W. P.
Published: April 2011

A 4-yr experiment was conducted to determine the effects of fertilization, incorporation of a legume and use of the Rumensin®-controlled release capsules (CRC) on productivity of cow-calf pairs grazing meadow bromegrass (Bromus biebersteinii Roem & Schult.). Four pasture treatments (T), alfalfa-grass fertilized (AF), alfalfa-grass unfertilized (AU), grass-only fertilized (GF) and grass-only unfertilized (GU), each replicated twice were compared. The eight 3.7-ha pastures were split into five equally sized paddocks and rotationally stocked with first-calf cows in 1995 and 1998, and with mature cows in 1996 and 1997. Half of the cows on each pasture received a Rumensin® CRC 1 wk prior to the start of the pasture season. Cow DMI was not influenced by fertilization or incorporation of a legume. However, cows treated with monensin consumed less (2.3% BW) compared to the control cows (2.5% BW, P < 0.05). Incorporation of alfalfa and fertilization improved pasture quality and resulted in higher CP and lower NDF content in forage selected by the animals. Monensin improved (P < 0.05) cow average daily gain (ADG, kg d-1) when grazing unfertilized grass and alfalfa-grass pastures, but did not influence gains of cows on fertilized pastures. Fertilizer application, legume incorporation and monensin administration did not affect milk yield or milk composition. Despite differences in diet quality, calf ADG for AU, AF, and GF were similar. However, calf ADG was lower for GU pastures (P < 0.05), probably as a result of the high fibre and low protein content of this pasture treatment. Both incorporation of alfalfa and fertilization increased total calf gain (kg ha-1); the greatest improvement was associated with fertilization. There were, however, economic advantages to legume incorporation, as the cost of the additional gain for GF and AF pastures averaged $1.08 and $0.79 kg-1 ha-1, and no extra costs were incurred for AU. Key words: Beef cows, calves, milk yield, pasture productivity, alfalfa, meadow bromegrass
Effect of iron bioavailability on performance, feed digestibility, blood parameters, and carcass characteristics at slaughter of grain-fed veal calves
Authors: Scott Shannon L. , Ghodratnama Ahmad
Published: April 2011

The effects of the iron chelator, EDTA, on performance, feed digestibility, blood parameters, and carcass quality were investigated in 48 veal calves (52 ± 4 kg BW) allocated to five treatment groups: a control, 5 mg EDTA mg-1 Fe in the feed for the last 8 or 18 wk before slaughter, or 15 mg EDTA mg-1 Fe in the feed for the last 8 or 18 wk before slaughter. Calves were fed a diet of whole corn and protein supplement (grain: supplement ratio of 2:1, 3.5:1 and 5:1 for starter, grower, and finisher production phases, respectively, resulting in crude protein levels of 21, 18 and 15%, respectively). The effects of both dose and duration of EDTA administration were analysed using a randomised complete block design in a factorial model. Daily DMI and ADG decreased linearly with an increasing dose of EDTA (P < 0.001). ADG declined linearly with increasing dose and duration of EDTA administration (P < 0.05). Blood iron, haemoglobin and haematocrit levels decreased linearly with increasing EDTA dose (P < 0.001) and duration of administration (P < 0.05). Carcass weight (kg) and yield (%) decreased linearly with both increasing EDTA dose (P < 0.001) and duration of EDTA administration (P < 0.05). Carcass classification improved linearly with increasing EDTA dose (P < 0.01). When EDTA is used as a dietary supplement for veal calves, there may be beneficial effects on carcass classification, but the dose and duration of administration need to be chosen judiciously to avoid deleterious effects on the well-being of the calves. Key words: Veal, iron bioavailability, EDTA, digestibility, haemoglobin
Effect of protein source on microbial protein synthesis and nutrient digestion in beef cattle fed barley grain-based diets
Authors: Koenig K. M. , Beauchemin K. A. , Rode L. M.
Published: April 2011

Four British cross heifers fitted with ruminal and duodenal cannulas were used in an experiment designed as a 4 × 4 Latin square. The basal diet was composed of 90% barley grain concentrate and 10% barley silage (DM basis) with either no protein supplementation (13.6% CP), or an additional 1.2% CP (% of DM) in the form of urea, canola meal (CM) or blood meal (BM). Ruminal ammonia N concentration was highest (P < 0.05) for the urea-supplemented diet (111 ± 18 mg N L-1), but no differences were observed among the control, CM- or BM-supplemented diets (59 to 78 mg N L-1; P > 0.05). Ruminal pH averaged 5.78 and was not affected by protein source (P = 0.97). Canola meal and BM tended (P < 0.10) to increase microbial N flow by 31 g N d-1 or 21% above the control diet. The response of microbial N flow to urea supplementation was intermediate between the control and true protein sources (P > 0.10). Ruminal OM and starch digestion were not affected by the dietary treatments (P > 0.10). In conclusion, barley grain-based finishing diets supplemented with protein sources of varying ruminal degradabilities increased microbial protein supply, but the improvement in microbial protein synthesis had no effect on diet fermentability. Key words: Protein supplements, microbial proteins, barley, beef cattle
Wheat by-products in poultry nutrition. Part I. Chemical and nutritive composition of wheat screenings, bakery by-products and wheat mill run
Authors: Slominski B. A. , Boros D. , Campbell L. D. , Guenter W. , Jones O.
Published: April 2011

A study was conducted to investigate the variability in chemical and nutritive composition of wheat screenings, bakery by-products and wheat mill run used by the feed industry in Canada. On average, and in comparison to wheat (as-fed basis), the wheat screenings (16 samples) contained less starch (457 vs. 560 g kg-1; P < 0.0001), less available energy (TMEn) (13.19 vs. 13.76 MJ kg-1; P < 0.05), similar amounts of sugars (19 vs. 12 g kg-1; P > 0.05), phytate phosphorus (2.4 vs. 3.0 g kg-1; P > 0.05), and higher levels of protein (151 vs. 126 g kg-1; P < 0.0001), fat (66 vs. 12 g kg-1; P < 0.0001) and non-starch polysaccharides (NSP) (100 vs. 91 g kg-1; P < 0.01). A negative relationship (P < 0.0001) between starch and fat contents of the wheat screenings samples was noted indicating that a decrease in starch content of 20 g kg-1 would result in an increase in fat content by approximately 9 g kg-1. This inverse relationship should result in the maintenance of a relatively high content of available energy in wheat screenings. The low level of glucosinolates in wheat screenings (min. 0.66, max. 4.24 µmol g-1) indicated that canola seed rather than wild and/or condiment mustard seed was a predominant oilseed in the samples and the main contributor to the high oil content. Bakery by-products (12 samples) contained 119 g kg-1 protein (as-fed basis) , 378 g kg-1 starch, 84 g kg-1 sugars, 81 g kg-1 fat, 87 g kg-1 NSP and 14.34 MJ kg-1 TMEn. Six samples of wheat mill run were evaluated, and on an as-fed basis were found to contain 165 g kg-1 protein, 264 g kg-1 starch, 36 g kg-1 sugars, 43 g kg-1 fat, 224 g kg-1 NSP and 5.2 g kg-1 phytate phosphorus. Although high levels of phytate phosphorus were found to be present in the mill run samples, the mill run was also found to contain the highest activity of endogenous phytase (2331 units kg-1) when compared to wheat (1358 units kg-1) or wheat screenings (1348 units kg-1). The total dietary fibre content of mill run was found to be 387 g kg-1 on average and was much higher than that determined for wheat screenings (195 g kg-1) and bakery by-products (134 g kg-1). Key words: Nutritive and botanical composition, antinutritional factors, fibre, phytate
Practical dietary levels of canola oil and tallow have differing effects on gilt and barrow performance and carcass composition
Authors: Dugan M. E. R. , Aalhus J. L. , Robertson W. M. , Rolland D. C. , Larsen I. L.
Published: April 2011

Previously we demonstrated that barrows produced leaner carcasses when fed 5% versus 2% canola oil. The present trial was conducted to determine if the same would be true for gilts or when feeding beef tallow (a source of saturated fatty acids). Four diets were fed (2 or 5% canola oil or digestible energy equivalents of tallow), and 27 gilts and 27 barrows were fed each diet. Experimental diets were fed from 49.4 to 113.5 kg body weight. Barrows fed 2% canola oil had similar average daily gains (ADG) relative to gilts (P > 0.05) fed any diet, but grew slower than barrows fed 5% canola oil (0.99 vs. 1.08 kg d-1; P < 0.05) and tended to have lower ADG relative to barrows fed diets containing tallow (P < 0.10). Barrows fed 2% canola oil had poorer feed conversion efficiency (kg feed kg-1 gain) relative to animals fed any other diet (P < 0.05). For barrows, feeding the 2% canola oil resulted in more subcutaneous fat relative to feeding 2.16% tallow (+18 g kg-1 lean cuts; P < 0.05), but the anticipated decrease in barrow subcutaneous fat when feeding 5% canola oil was not significant (-4 g kg-1 lean cuts; P > 0.05). No practical differences in pork quality were noted when feeding any diet, but backfat became more unsaturated when feeding canola oil and led to softer backfat (P < 0.05). When feeding canola oil to barrows, it may therefore be more practical to feed higher levels than lower levels due to improvements in animal performance without changes in body composition, but care must be taken so that fat softness does not become an issue. Key words: Canola oil, tallow, barrow, gilt, carcass composition, average daily gain, feed conversion
Fiber-optic spectrophotometry of streaking in pork loins injected with sodium chloride and tripolyphosphate
Authors: Swatland H. J.
Published: April 2011

Enhanced pork produced by needle injection of sodium chloride and tripolyphosphate loses its visual appeal if it has pale streaks on a dark background. Reflectance (R) spectrophotometry was used to test the hypothesis needle injection causes pale streaks by elution of myoglobin. Pale streaks in commercial pork loins (n = 10) had higher R than dark streaks (P < 0.01 from 350 to 590 nm) but differences between pale and dark streaks were almost a linear function of wavelength (r = -0.92, P < 0.0005) with no evidence of myoglobin elution. Using the same apparatus, myoglobin elution was detected in small disks of pork perfused experimentally for 1 h (n = 31 spectra, 2 min apart), comparing water (control, n = 5 disks) with commercial injection solution (n = 5 disks). Myoglobin elution by water increased R (P < 0.005) from 350 to 650 nm with a maximum effect at 440 nm, close to the Soret absorbance band for myoglobin. Perfusion of disks with commercial injection solution produced a complex result with the myoglobin elution pattern (increased R peaking at 440 nm) superimposed on an overall decrease in R, probably from sodium salts dissolving myofibrillar proteins (P < 0.005 from 350 to 360 nm, from 400 to 420 nm, at 440 nm, and from 460 to 540 nm). Thus, there was no support for the initial working hypothesis pale streaks are caused by myoglobin elution because the myoglobin elution pattern (increased R peaking at 440 nm) was absent in commercial pork loins. If perfusing small disks of pork is a valid experimental model of what happens in needle-injected loins, transient pale streaks might be muscle fasciculi not yet reached by injected solution. Key words: Enhanced pork, streaking, needle injection
Feeding value of dehulled flaxseed
Authors: Leeson and L. J. Caston S.
Published: April 2011

Laying hens were fed diets containing 10% flaxseed or 10% flaxseed that was either 50 or 90% dehulled. Dehulling was achieved mechanically, without solvent extraction. AMEn of 90% dehulled flaxseed was significantly (P < 0.01) increased relative to conventional flax (5073 vs. 3672 kcal kg-1). The linolenic acid content of eggs from birds fed 90% dehulled vs. regular flax was also increased from 203 to 247 mg/50 g egg. Dehulling of flax seems to improve its nutritive value. Key words: Flaxseed, layers
Impact of the relative emphasis on growth and litter size in a maternal index for selecting sheep
Authors: Tosh J. J. , Wilton J. W.
Published: April 2011

Selection responses in sheep were predicted for a maternal index with different emphases on litter size and lamb growth to assess the need for correct economic values. Ratios of economic values for litter size relative to growth from 2 to 200 were tested. Genetic change per generation in market weight of lambs (1.75 to 0.03 kg) was sensitive, but genetic change per generation in number of lambs born (0.11 to 0.17) was practically independent of the economic values applied in the index. Key words: Economic values, genetic improvement, maternal characteristics, selection, sheep
Effects of dietary crude protein level and sugar beet pulp inclusion on nitrogen excretion patterns in grower and finisher pigs
Authors: Smith L. F. , Lemay S. P. , Patience J. F. , Zijlstra R. T.
Published: April 2011

Diets with high and low protein content and with or without sugar beet pulp (SBP) were tested in grower and finisher pigs; SBP replaced wheat in grower and barley in finisher pig diets. Urinary N was lowered (P < 0.05) and faecal N not affected (P > 0.10) by low-protein diets. In grower pigs, SBP lowered urinary N (P < 0.05) and interacted with dietary protein (P < 0.10). In finisher pigs, SBP did not affect N excretion patterns (P > 0.10). Reduced dietary protein consistently reduced urinary N excretion, whereas effects of SBP inclusion were dependent on dietary protein content or replaced cereal grain. Key words: Excretion, fibre, nitrogen, pigs, protein
Use of dietary tea seeds to manipulate the rumen ciliate protozoa population in sheep
Authors: Ivan and T. Entz M.
Published: April 2011

Eighteen rumen cannulated sheep in three groups of six were supplemented with tea seeds at 0 (control), 3 or 6% of the dietary dry matter in a 22-d experiment. Rumen fluid samples were collected on 3 d before and on various days during the experiment. The concentration of protozoa in rumen fluid was not affected by the tea seed supplements (P > 0.05), but the numerical concentration of the Entodinium genera declined by 12% (P < 0.05) and that of cellulolytic protozoa increased by 90% (P < 0.05) due to the 6% tea seed supplement. The associated percentage in the rumen ciliate protozoa population of the cellulolytic protozoa increased (P < 0.05) and that of the Entodinium genera decreased (P < 0.05) due to the 6% supplement. There were no effects (P > 0.05) of the 3% tea seed supplement on the protozoa population parameters. Since ammonia and volatile fatty acid concentrations were not affected (P > 0.05) it was apparent that the tea seed supplements did not influence rumen fermentation. The positive effect of the 6% tea seed supplement on the ciliate protozoa population obtained in the present study was relatively modest. Because the seeds contain astringent properties, higher than 6% dietary supplements of tea seeds can be harmful to animals. It was therefore concluded that tea seeds are of no apparent value as an antiprotozoal dietary component in ruminant production. Key words: Tea seeds, ciliate protozoa, rumen fluid, sheep
Effects of prolactin inhibition during late gestation on the immunity of gilts and foetuses
Authors: Lessard M. , Dupuis M. , Farmer C.
Published: April 2011

The goal of the present study was to determine the effects of inhibiting prolactin (PRL) synthesis for three consecutive 20-d periods during the second half of gestation, on the immune status of gilts and their foetuses. Crossbred gilts were randomly assigned as controls (n = 12) or received 10 mg of bromocriptine orally three times daily from days 50 to 69 (BR50, n = 12), days 70 to 89 (BR70, n = 12), or days 90 to 109 (BR90, n = 12) of gestation. All gilts were injected subcutaneously with ovalbumin (OVA) on days 53 and 72 of gestation. Blood samples were collected on days 50, 60, 70, 90 and 109 of gestation to evaluate the antibody response. Cellular immunity, as measured by lymphocyte proliferative response and production of interferon-γ, was characterized on controls and BR50 gilts until the end of gestation. Six foetuses from five litters per treatment were selected and their thymus and spleen were excised and weighed. Splenocytes and thymocytes were assayed to characterize lymphocyte sub-populations and to evaluate splenocyte responses to mitogenic stimulation. Average spleen weight in foetuses from BR90 gilts was significantly lower (P < 0.05) than that of foetuses from control or BR70 gilts. In all gilts treated with bromocriptine,percentages of CD4+ and CD8+ lymphocyte populations in foetus spleens were numerically reduced compared with those obtained in foetus from control gilts but the differences were not significant. In BR50 gilts, inhibition of PRL synthesis did not affect the proliferative response of lymphocytes to mitogenic stimulations compared with control group, but tended (P = 0.13) to increase the production of interferon-γ. A time effect showed that production of interferon-γ by leukocytes was reduced (P < 0.02) on days 80 and 100 compared with days 50 and 70, regardless of bromocriptine treatment. The antibody response of gilts to OVA was not affected by bromocriptine treatments. In conclusion, inhibition of PRL synthesis by bromocriptine did not significantly affect immune response of pregnant gilts. In foetuses, although the differences between treatments were not significant, data suggest that the foetal development of immune tissues seems to be impaired by bromocriptine treatment. Key words: Bromocriptine, prolactin, immunity, pregnancy, sow