bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of adaptation to lasalocid or monensin on in vitro fermentation of prairie hay
Authors: Duff G. C. , Galyean M. L. , Branine M. E.
Published: March 2010

Effects of adaptation to lasalocid (L) or monensin (M) on in vitro fermentation of prairie hay were measured in a replicated in vitro experiment with a 3 × 3 factorial arrangement of treatments. Treatments were adaptation of ruminal fluid donor steers (ADAPT; no ionophore, 200 mg steer−1 d−1 of L, or 200 mg steer−1 d−1 of M) and culture ionophores (IONO; no ionophore, 4 μg mL−1 of L, or 4 μg mL−1 of M). At 12 and 96 h of incubation, in vitro dry matter disappearance (IVDMD) was increased (P < 0.10 and P < 0.05, respectively) by M-ADAPT compared with L-ADAPT, and IVDMD was increased (P < 0.10) by ionophore adaptation treatments compared with control at 96 h of incubation. In contrast to effects of adaptation treatments, culture ionophore treatments decreased (P < 0.01) IVDMD at 12 and 96 h compared with control; furthermore, at 12 h, M in culture decreased (P < 0.05) IVDMD compared with L in culture. At 24, 48, and 72 h addition of both L and M in culture to unadapted inoculum decreased (P < 0.10) IVDMD compared with control. Addition of M in culture decreased (P < 0.10) the rate of IVDMD when added to unadapted and L-adapted inoculum compared with C and L in culture. Acetate was decreased (P < 0.10), propionate increased (P < 0.10), and the acetate:propionate ratio decreased (P < 0.05) by ionophore adaptation compared with control at 24 h of incubation and by culture ionophore treatments compared with control at 48 h of incubation. Results indicate that effects of ionophores on in vitro fermentation of prairie hay depended on adaptation of the donor animals to the ionophores. In addition, monensin, when added to the culture, seemed to be more detrimental to in vitro fermentation of a low-quality forage than lasalocid. Key words: In vitro, fermentation, ionophores, monensin, lasalocid
Intake, digestibility and aerobic stability of barley silage inoculated with mixtures of Lactobacillus plantarum and Enterococcus faecium
Authors: McAllister T. A. , Selinger L. B. , McMahon L. R. , Bae H. D. , Lysyk T. J. , Oosting S. J. , Cheng K.-J.
Published: March 2010

The effect of ensiling barley treated with two bacterial inoculants containing mixtures of Lactobacillus plantarum and Enterococcus faecium (1.0 × 105 cfu g−1 as fed silage) on the nutritional value and aerobic stability of barley silage was examined. Inoculants differed in the strains they contained and were originally selected by Pioneer Hi-Bred International for use with corn or alfalfa silage, SILA-BAC® (1174), or with grass silage (X2637). Concentrations of water-soluble carbohydrates were higher (P < 0.05) in inoculated than in control silages. Although inoculants appeared to increase the numbers of lactic acid producing bacteria (LAB) at ensiling, post-ensiling numbers (cfu g−1) of yeasts and molds were lower (P < 0.05) in inoculated than in control silages. Lactic acid concentrations and pH were similar among the silages and variations m the growth of yeast and mold populations could not be explained by differences in the production of volatile fatty acids (VFA) among silages. Inoculation of barley silage with either inoculant increased (P < 0.01) the average daily gain of lambs. A digestibility experiment with 12 growing ram lambs showed that inoculants did not alter (P > 0.05) DM intake, feed efficiency or the digestion of DM, organic matter, acid detergent fiber (ADF) and neutral detergent fiber (NDF). Nitrogen intake and retention were greater (P < 0.05) in lambs fed silage inoculated with 1174 as compared with control silage. Yeast populations were increased (P < 0.05) in control and 1174 after 2 d of exposure to air but it required 13 d for a similar yeast population to be established in X2637 silage. Increases in the mold populations within the silages were noted after 2, 5 and 13 d of exposure to air for control, 1174 and X2637, respectively. The temperature of control silage increased (P < 0.05) 2 d after exposure to air, whereas increases in temperature were delayed for 4 d in 1174 and 8 d in X2637. Temperatures rose as high as 30 °C in control silage, but did not exceed 24 °C in inoculated silages during the 13 d period. Key words: Barley silage, inoculant, digestion, aerobic stability, sheep, gain
Growth dependent changes in the chemical composition of proximal tibial articular cartilage and growth plate of broiler chickens
Authors: Nakano T. , Sim J. S.
Published: March 2010

Chemical composition of the proximal tibial articular cartilage and growth plate of broiler chickens from seven age groups (1, 8, 14, 22, 29, 36, and 43 d old) was studied. In the articular cartilage, the contents of dry matter, collagen measured as hydroxyproline, and keratan sulfate increased (P < 0.05), and the content of sialic acid decreased (P < 0.05) as age advanced. The content of chondroitin sulfate measured as uronic acid and the proportion of hyaluronic acid in total glycosaminoglycan (GAG) were relatively constant (P > 0.05) among the age groups. In the growth plate, the contents of chondroitin sulfate and keratan sulfate increased (P < 0.05) with age, while the contents of dry matter, sialic acid, and collagen were similar among the age groups. The proportion of hyaluronic acid in total GAG decreased at the age of 8 d, and remained relatively constant thereafter. The growth dependent changes observed in the concentration of chondroitin sulfate in the broiler chicken cartilage were different from those in other species which have been reported to show a decrease during early postnatal growth. Key words: Tibia, epiphyseal cartilage, growth plate, broiler chicken, age
Effect of dietary calcium level on plasma proteins and calcium flux occurring during a 24 h ovulatory cycle
Authors: Clunies M. , Leeson S.
Published: March 2010

An experiment was carried out to determine whether feeding different calcium levels from the onset of production has an effect on medullary bone reserves, plasma proteins and ultimately shell formation. A total of 80 Single Comb White Leghorn hens photostimulated at 17 wk of age were fed a 2.5% Ca diet until the appearance of the first egg. Thereafter diets providing 2.5, 3.0, 3.5, 4.0, or 4.5% Ca were fed to groups of 16 hens. At 6, 12, 18, or 24 h post-ovrposition, blood was collected from four hens per treatment, which were then euthanized and developing shells and bones sampled. As dietary Ca increased, plasma Ca, protein, and protein-bound phosphorus concentrations also increased (P < 0.05). Dietary Ca level had no effect (P > 0.05) on the % Ca or total Ca content of bone ends or medullary bone. As dietary Ca concentration increased, both shell ash and shell Ca increased (P < 0.05). Regardless of dietary Ca, shell secretion was most rapid during 12–18 h of the ovulatory cycle (postoviposition). Key words: Calcium, medullary bone, shell calcification, plasma proteins
Influence of processing on dietary enzyme effect and nutritive value of diets for laying hens
Authors: Vranjes M. Vukic , Pfirter H. P. , Wenk C.
Published: March 2010

Two experiments were carried out to examine the influence of a Trichoderma viride enzyme complex [cellulase, endo-β-(1:3)(1:4)-glucanase, xylanase] on nutrient utilization and production parameters of laying hens. In exp. 1, the influence of extrusion (110 °C, 20 s) and dietary enzyme addition on the nutritive value of the diet was tested. Dietary treatments were as follows: M and MR, unprocessed feed, plus or minus enzyme; E, feed extruded without enzyme; ER-1, feed extruded with enzyme; ER-2, enzyme added after extrusion. Diets were fed in mash form. Partial inactivation of the enzyme took place as indicated by a significant difference in energy use in groups ER-1 and ER-2 (73 vs. 75%). According to the enzyme-affected changes of the feed extract viscosity, 65% of the enzyme initial efficacy were lost as a result of extrusion. Nevertheless, the addition of enzyme before extrusion (ER-1) was not without effect, as birds fed the ER-1 diet had improved energy (73 vs. 71%) and fat utilization (89 vs. 85%) as compared with those fed the extruded unsupplemented diet (E). Extrusion decreased feed AME content by 0.3 MJ kg−1. A significant interaction between processing and enzyme for energy and fat utilization indicated a greater beneficial effect of enzyme in extruded feed. Experiment 2 was arranged in a same way as exp. 1, with the exception that pelleting (70 °C) replaced the extrusion process. Feed extract viscosity measurements revealed that pelleting reduced initial enzyme efficacy by 52%. Despite this, enzyme improved nutrient utilization in unprocessed and pelleted diet to the same extent, and no further improvements were observed by supplementation of the feed after processing. Pelleting itself did not affect nutritive value of the feed. Key words: Enzyme supplementation, laying hens, feed processing
Lignosulfonate-treated canola meal for nursing beef calves
Authors: Beauchemin K. A. , Bailey D. R. C. , McAllister T. A. , Cheng K.-J.
Published: March 2010

A study was conducted to determine the effects of lignosulfonate and heat treatment of canola meal on protein degradability, and to evaluate whether feeding treated canola meal to nursing beef calves enhances preweaning growth. Four supplements were formulated to contain 31% crude protein (CP) using either: (1) untreated canola meal (UTC), (2) heat-treated canola meal (HTC; 100 °C for 1 h), (3) lignosulfonate-treated canola meal (LTC; 5% calcium lignosulfonate and 100 °C for 1 h), or (4) corn distillers' dried grains (DDG). Degradability of canola meal CP was reduced significantly from 55.1% (measured in sacco) to 43.2% by heat, and to 26.7% by lignosulfonate treatment. One hundred and three nursing crossbred calves were given access to either no supplement (control) or one of the four supplements. Weight gain (kg d−1) increased (P < 0.05) from 0.90 for the control to 1.05 for calves fed DDG, and further increased (P < 0.05) to 1.16, 1.16 and 1.18 for calves fed UTC, HTC, and LTC, respectively. Consequently, calves fed canola meal gained 30.8 kg more (P < 0.05) than those fed control, and 12.8 kg more (P < 0.05) than those fed DDG. The performance of suckling calves during the grazing season and body condition of their dams were enhanced by offering canola-based creep feeds. Although degradability of canola meal CP was substantially lowered by lignosulfonate treatment, calf performance was not further enhanced by feeding treated canola meal. Key words: Beef cattle, creep feeding, canola meal, lignosulfonate, heat-treatment, distillers' dried grains, protein degradability
Age, protein level and sex as factors influencing gastrocnemius muscle growth in BALB/c mice from weaning to 50 days of age
Authors: López-Oliva MaE. , Agis-Torres A. , Unzaga MaT. , Muñoz-Martínez E.
Published: March 2010

The effects of age, dietary protein level [12% (medium protein) or 20% (high protein)], and sex on muscle growth of female (f) and male (m) BALB/c mice between weaning (21 d) and 50 d of age were studied. Animals were housed individually and feed intake and body weight (BW) were recorded daily. In the total experimental period (29 d), six partial experimental periods were established. At 25, 30, 35, 40, 45 and 50 d of age, five mice of each group (MPf, MPm, HPf, HPm) were slaughtered and gastrocnemius muscle growth was studied. Based on BW and muscle weight (MW) measures, values of growth parameters were estimated. Feed consumption rate (FCR) increased in all groups, but it nearly stabilized with age in HP mice. BW, estimated muscle weight (EMW), muscle weight gain (MWG), absolute muscle protein (AMP) and muscle protein gain (MPG) increased in MP and HP mice during the experiment. Relative muscle protein (RMP) increased in MP while it decreased in HP mice with age. Also, absolute and fractional muscle weight growth rates (AWGR and FWGR, respectively) and absolute and fractional muscle protein growth rates (APGR and FPGR, respectively) decreased in all mice tested (age-dependent), except in HPf mice where it remained plateaued in time (age-independent). At 21 d the highest AWGR, FWGR, APGR, and FPGR values were registered in MP mice. Diet and sex influenced the relative allometric proportions of muscle to the organism as a whole. Muscle protein growth of MP mice versus MW growth was enhanced, resulting in an increase of growth coefficients as compared to HP mice. Also, the contribution of muscle protein to carcass protein and the efficiency of protein intake utilization were higher in MP mice than in HP mice, while efficiency of energy intake was similar in both groups. In conclusion, hyperphagia and increased efficiency of protein utilization induced a near-normal muscle growth in MP growing BALB/c mice. Key words: Age, protein level, sex, muscle growth, BALB/c mice
Observations on the responses of feedlot cattle to attempted environmental enrichment
Authors: Pelley M. C. , Lirette A. , Tennessen T.
Published: March 2010

Twenty-four 9-mo-old Hereford steers were randomly divided into three groups of eight to determine if the steers would react to enrichment objects, and if one object would be used more than the others. The experiment design was a 3 × 3 Latin square consisting of three treatments, three groups and three periods of 2 wk. The results indicated that the steers did react (P < 0.05) to enrichment objects and preferred (P < 0.05) one object above the others. Key words: Beef cattle, feedlots, environmental enrichment
Estrus detection with activity tags in dairy cows housed in tie-stalls
Authors: Kennedy A. D. , Ingalls J. R.
Published: March 2010

Activity tags were attached to the rear ankle of 11 Holstein dairy cows maintained indoors in tie-stalls except for a 3 h daily exercise period. Cows were monitored for 56–63 d. Activity tags detected 18/27 (67%) of estruses with 22 incorrect indications (false positives) compared to a visual detection rate of 19% with three false positives. Use of a correction method decreased the number of activity tag false positives considerably with only a decrease of two in the number of correctly identified estruses. Key words: Activity, estrus detection, tie-stall, dairy cow
Ad libitum versus restricted feeding of barley- and corn-based feedlot diets
Authors: Mathison G. W. , Engstrom D. F.
Published: March 2010

A 2 × 2 factorially designed experiment in which barley or corn grains were fed ad libitum or at 96% ad libitum to 100 steers was conducted to test the hypothesis that type of grain fed would affect any responses in feed conversion efficiency obtained by restricting intake. Feed restriction resulted in a 22% reduction (P = 0.01) in fat cover but the numerical improvement in feed conversion efficiency of 3% was not significant (P = 0.32). Grain type had no detectable influence on feed-lot performance. Key words: Ad libitum, restricted feeding, steers, barley, corn, feedlot
Genetic evaluation of ewe performance in Outaouais Arcott and Suffolk sheep and their crosses
Authors: Shafto A. M. , Crow G. H. , Parker R. J. , Palmer W. M. , Shrestha J. N. B. , McVetty P. B.
Published: March 2010

Ewes from a newly developed sheep breed in Canada, the Outaouais Arcott, consistently out-performed Suffolk ewes in prolificacy at birth and at 42 d of age by 0.37 lambs at first parity and by 0.55 and 0.41 lambs, respectively, over all parities. In contrast, mean litter weights of Suffolk and Outaouais ewes did not differ at these times. Additive genetic effects in prolificacy and litter weight tended to favour the Outaouais breed over the Suffolk breed at first parity. Corresponding values over all panties were significant, favouring the Outaouais, for both prolificacy and litter weight at 42 d of age. Suffolk ewes excelled in maternal genetic effects for litter weight for all parities at birth and 42 d of age. Reciprocal cross ewes of the Outaouais and Suffolk breeds were similar (P > 0.05) in prolifacacy and litter weight. In general, crossbred ewes consistently exceeded Suffolk ewes in prolificacy but were not significantly different from Outaouais ewes. Though not always significant, crossbred ewes exceeded the average of their purebred parents m prolifacacy and litter weight. Furthermore, estimates of heterosis were always positive, and the 19% value for litter weight at 42 d of age at first parity was significant. This study, conducted over 6 yr, demonstrates the superiority of the Outaouais breed for production of commercial crossbred ewes to perform in a moderately intensive, semi-confinement operation. This superiority exists in addition to the previously-established ability of the Outaouais ewe to produce large litters in an 8-mo breeding cycle. Key words: Ewes, prolifacacy, litter weight, genetic effects, heterosis
Dose-response effects of vitamin E supplementation on growth performance and meat characteristics in beef and dairy steers
Authors: Garber M. J. , Roeder R. A. , Pumfrey W. M. , Schelling G. T. , Davidson P. M.
Published: March 2010

This study examined dose-response effects of supplemental dietary dl-α-tocopheryl acetate (VE) on growth performance, immune response, and carcass and meat sensory characteristics in two breeds of cattle. Seventy-five crossbred beef steers (361 ± 22 kg) were blocked by weight, randomly assigned to one of five treatment groups, and fed a ration supplemented with 0, 250, 500, 1000 or 2000 IU VE steer−1 d−1. Sixty Holstein steers (366 ± 22 kg were similarly blocked and allocated (no 250 IU treatment). Four days post-slaughter the left sirloin subprimal of each steer was removed and vacuum packaged. On day 13, small cores were cut from the gluteus medius (GM) and packaged with O2-permeable wrap; these were then displayed under 45-W natural white light for up to 10 d at 4 °C. Serum α-tocopherol increased (P < 0.0001) with increasing VE in both breeds, although more so (P < 0.0001) in beef steers. The GM α-tocopherol levels increased linearly (P < 0.0001) with increasing VE, but more so (P < 0.0002) in beef steers. The levels of α-tocopherol in semimembranosus muscle, perirenal and subcutaneous fat, and liver also increased linearly (P < 0.0001) in both breeds. Growth performance of all steers and carcass characteristics of beef steers were not affected (P > 0.10) by VE. Dairy steers receiving 1000 IU d−1 had darker (P < 0.03) ribeyes. There were no effects (P > 0.10) of VE on sensory attributes of frozen steaks. Surface metmyoglobin formation was deterred by VE supplementation in meat from beef (linear, P < 0.016) but not dairy (P > 0.10) steers. Lipid oxidation was suppressed (linear, P < 0.0002) by VE but more so (P < 0.0001) in beef than in dairy meat (72.9% vs. 40.0% suppression, respectively, at 2000 IU d−1). Immune response increased (P < 0.074) at higher levels of VE. In summary, VE supplementation improved immune response and increased serum and muscle α-tocopherol levels, resulting in delayed metmyoglobin formation (beef) and lipid oxidation (beef and dairy) in a dose-dependent manner. Supplemental VE was more effective in meat from beef steers than in that from dairy steers. Key words: Vitamin E, immunity, growth, carcass
Genetic parameters for feed intake and efficiency in dry pregnant beef cows
Authors: Fan L. Q. , Wilton J. W. , Colucci P. E.
Published: March 2010

Genetic parameters of feed efficiency and traits relative to feed efficiency for dry pregnant beef cows were estimated from data collected from 1980 to 1988 at the Elora Beef Research Centre, Guelph, Ontario. Measurements of individual feed intake were available for 90 d immediately before calving. Estimates of parameters were obtained using derivative-free restricted maximum likelihood (DFREML), with an individual-animal model with year-season, sex of fetus, parity breeding system, covariate daily backfat change, and genetic and permanent environmental effects. The data included 729 observations, 337 cows, 278 dam–maternal grand dam pairs, and 208 sires of cows. Feed efficiency for pre-calving gain of fetus was calculated as pre-calving gain relative to energy consumed for maintenance and pregnancy, with adjustment of intake for weight change by National Research Council (NRC) standards (FE) or by regression analysis (FER). Residual feed consumption was calculated as energy intake minus energy requirements, with requirements estimated by NRC standards (RFC) or by regression (RFCR). Heritabilities for Hereford alone and total data, respectively, were 0.03 and 0.16 for daily metabolizable energy intake (MEI); 0.20 and 0.44 for metabolic body weight (MBW); 0.28 and 0.22 for fetal pre-calving average daily gain (PADG); 0.11 and 0.05 for FE; 0.28 and 0.20 for FER; 0.01 and 0.04 for RFC; and 0.03 and 0.22 for RFCR. Genetic and phenotypic correlations indicated a positive association of energy intake with pre-calving fetal gain and weight of cow, although correlations with weight of cow were low. Residual feed consumption for the total data was not genetically associated with MEI or PADG, moderately associated with MBW, and highly negatively associated with FE. Key words: Genetic parameter, feed efficiency, pregnancy, beef
Genetic parameters for feed intake and efficiency in lactating beef cows
Authors: Fan L. Q. , Wilton J. W. , Colucci P. E.
Published: March 2010

Genetic parameters of feed intake and efficiency and production traits for lactating beef cows were estimated from data collected from 1980 to 1988 at the Elora Beef Research Centre, Guelph, Ontario. Estimates were obtained using restricted maximum likelihood (REML) with an individual animal model with year–season–treatment, sex of calf, parity, breeding system, covariate daily change of backfat depth and direct genetic and permanent environmental effects. The data included 1174 observations, 511 cows, 369 dam–maternal grand dam pairs and 245 sires of cows. Feed efficiency for milk was calculated as milk yield relative to energy consumed for milk and maintenance and residual feed consumption as estimated energy intake minus energy requirements as estimated by the National Research Council. Heritabilities for Herefords alone and total data, respectively, were estimated to be 0.02 and 0.11 for cow's daily ME intake (MEI), 0.26 and 0.26 for daily milk yield (DMY), 0.45 and 0.33 for milk fat percentage (MFP), 0.29 and 0.40 for metabolic body weight (MBW), 0.21 and 0.10 for calf weaning weight as a proportion of cow weight at weaning (PPW), 0.18 and 0.11 for feed efficiency for milk (FE), and 0.23 and 0.03 for residual feed consumption (RFC). Genetic correlations of output (DMY) and input (MEI) were 0.31 for Hereford and 0.75 for the total data. Genetic correlations of RFC with both output (DMY) and input (MEI) were low. Genetically, PPW was positively associated with FE and DMY and negatively associated with MBW. Key words: Genetic parameters, feed efficiency, lactation, beef cow
Tolerance of young pigs for dietary vitamin A and μ-carotene, with special reference to the immune response
Authors: Blair R. , Facon M. , Owen B. D. , Jacob J. P. , Bildfell R. J.
Published: March 2010

Guidelines need to be drawn up for the fortification of diets with vitamin A, because of its known toxicity. In exp. 1, 35 pigs aged 5 wk and weighing about 10 kg were placed in individual cages and allocated to seven dietary treatments for 28 d. In treatments 1–6 the levels of vitamin A or β-carotene represented 1, 10 or 100 times the National Research Council (1988) requirement for vitamin A, and in treatment 7 vitamin A and β-carotene were combined 50:50 to provide a total representing 100 times the vitamin A requirement. The vitamin A biopotency of β-carotene was assumed to be 200 IU mg−1. There was no significant effect of vitamin A or β-carotene on growth performance, plasma Escherichia coli antibody, or on lymphocyte proliferation. Serum retinol at 14 and 28 d increased as the level of dietary vitamin A increased but the effect was not significant (P = 0.241 and 0.073, respectively), β-carotene gave higher serum retinol at 14 and 28 d than vitamin A, but the effect was not significant (P = 0.232 and 0.059, respectively). Liver retinol increased with increasing level of dietary vitamin A or β-carotene (P < 0.001). In exp. 2, 30 pigs aged 5 wk and of 10 kg initial weight were penned in groups of three, injected i.m. and 3 wk later with 2 mL of a commercial TGE vaccine, and were fed for 5 wk on diets containing graded levels of vitamin A representing 0, 1, 10, 100 and 200 times the requirement. Growth performance was not significantly affected by treatment, nor was the morphology of tissues integral to the immune system. Anti-TGE titre increased markedly after the second injection of vaccine, but was not affected at any stage by treatment. Serum retinol increased significantly (P < 0.002) and serum tocopherol was reduced significantly (P < 0.001) with increasing dietary vitamin A. The data fitted a cubic model. Liver retinol was increased significantly (P < 0.001) and liver tocopherol was reduced significantly (P < 0.001) with increasing dietary vitamin A. The data fitted a cubic model. These results show that increasing dietary vitamin A raises both the circulating and storage levels of retinol, and that the response may be predicted from the equations derived. The results also show that increasing dietary vitamin A has a significant depressing effect on vitamin E status. Taken in conjunction with previous findings from our laboratory, the results suggest that the tolerable dietary range of vitamin A for the young pig in the weight range 10–30 kg is up to 10 times the requirement. Key words: imunity, pig, β-carotene, toxicity, vitamin A, vitamin E
Changing epidemiology of ascites in broiler chickens
Authors: Olkowski A. A. , Classen H. L. , Kumor L.
Published: March 2010

Ascites has become a major economic problem in modern broiler operations world wide. Estimated losses to the global economy likely amount to hundreds of millions of dollars annually, however, accurate statistics are not available. Epidemiological information on incidence of ascites is scanty. The present work examines the condemnation records between 1986 and 1994 from federally inspected slaughtering plants in Canada. The analysis reveals that there has been a steady increase in ascites condemnation during this period. National average figures showed a nearly sixfold increase in condemnations due to ascites from 1986 to 1994. It is estimated that in Canada some 6–8 million chickens developed ascites in 1994. The present data have shown an alarming trend in the epidemiology of ascites. Key words: Chicken, broiler, ascites, condemnation, epidemiology
Dim light does not reduce fighting or wounding of newly mixed pigs at weaning
Authors: Christison G. I.
Published: March 2010

Pigs weaned at 27 d were mixed into groups of nine and exposed to constant illumination of 5 or 100 lx. Behavior was categorized every 10 min for 72 h and all fights were counted. Eating, drinking, lying and fighting patterns were similar in both light groups. The peak number of fights occurred 18–24 h post-weaning, concurrent with the major feeding episode. Ears and shoulders were scored for wounds 1 and 4 d after weaning; light intensity did not affect (P > 0.50) wound scores. Key words: Aggression, fight, light, pig, weaning, wound
Carcass and organoleptic characteristics of meat from steers grazed on alfalfa/grass pastures and finished on grain
Authors: McCaughey W. P. , Cliplef R. L.
Published: March 2010

Forty-eight pasture-raised steers were fed grain for 0, 33 or 75 d before slaughter. Approximately 69% of steers slaughtered directly off pasture met A-grade standards with the remainder grading B1 due to insufficient marbling. However, a 33-d period of grain feeding was sufficient for all steers to meet A-grade standards. Pasture-finished steers had lower predicted lean yields, smaller rib-eye areas, and darker coloured meat than grain-finished steers. Grain feeding did not change fat colour or texture, nor tenderness, juiciness, flavour and overall acceptability. Key words: Forage finishing, carcass quality, beef, pasture, grain
Uterine involution time and ovarian activity in weaned and suckling ewes
Authors: Rubianes E. , Ungerfeld R. , Viñoles C. , Carbajal B. , Castro T. de , Ibarra D.
Published: March 2010

Uterine involution time and ovarian activity were studied in autumn- and spring-lambing ewes. Macroscopic uterine involution was completed earlier in autumn-lambing ewes and this can be related with an earlier resumption of ovarian endocrine activity. The uterus of spring-lambing ewes reached a smaller size, similar to that found in anestrous ewes. Weaning immediately after parturition did not affect the time of uterine involution. Key words: Ewes, follicles, postpartum, uterine involution, weaning
Fetal survival and conceptus development after 42 days of gestation in gilts and sows in response to folic acid supplementation
Authors: Harper A. F. , Lindemann M. D. , Kornegay E. T.
Published: March 2010

The effects of feeding 2 ppm supplemental folic acid (FA) on fetal survival and development were assessed in sows (n = 32). Number of live fetuses and fetal survival at day 45 ± 3 of gestation was not influenced by FA. Fetal pig weight, length, protein and RNA content were increased (P < 0.05) with FA treatment, suggesting enhanced development of embryo/fetal tissues with maternal FA supplementation. Key words: Folic acid, gilt, sow, fetal pigs
Uniform or heterogeneous weight groups as factors in mixing weanling pigs
Authors: Francis D. A. , Christison G. I. , Cymbaluk N. F.
Published: March 2010

A series of trials evaluated the behavior and performance of pigs grouped into three main categories at weaning: (1) unmixed litters, (2) mixed into uniform body weight groups (light, medium and heavy) and (3) mixed into heterogeneous weight groups. The effects of grouping on performance criteria were conflicting among trials and with time after weaning. In trial 1, heterogeneous groups had lower (P = 0.09) average daily gain to 5 d after weaning than intact litters. The reverse was observed in trial 2. In trial 3, uniform weight groups grew more rapidly (P < 0.01) than heterogenous groups. These treatment differences persisted through 19 d post-weaning for pigs in trials 1 and 2 but were no longer evident in trial 3. Play/fight behavior was highest (P < 0.01) among uniform weight groups resulting in an increased wounding score for head and shoulders of pigs in medium and heavy weight groups. In trial 1, structures which allowed individuals to hide their heads were available for the first 5 d but did not affect behavior or wounding. In trial 2, pigs from the three main groupings were mixed again on day 19 into three new groupings (unmixed, uniform weight or heterogenous weight). There were no performance differences among the nine grouping combinations 40 d after weaning. We conclude that if litter groups cannot be maintained after weaning, it may be advantageous to mix newly weaned pigs into uniform weight groups although the benefit is not consistently present. If space is limited, the greatest benefit would be to group light weight pigs together. Key words: Pigs, weanlings, behavior, lesions, head hides, mixing
Adjusting scrotal circumference of yearling beef bulls in five composites
Authors: Kress D. D. , Davis K. C. , Tess M. W.
Published: March 2010

Records from five composite strains of beef cattle were used to estimate age of dam and age of bull adjustment factors for scrotal circumference of yearling bulls. Data were obtained from Beefbooster Cattle Alberta Ltd., Calgary, AB. There were 5244 scrotal circumference records on yearling bulls born from 1987 to 1992. M1, M2, and M4 were maternal composites selected primarily for weaning weight, M3 was a terminal composite selected primarily for low birth weight, and TX was a terminal composite selected primarily for feedlot gain. The prominent foundation breeds were Angus for M1, Hereford for M2, various small breeds for M3, Limousin and Gelbvieh for M4, and Charolais for TX. Statistical analyses were performed for each composite separately according to the model that included the fixed effects of herd, year, age of dam and linear (quadratic was not significant) regression on age of bull at measurement. Average age at measurement was 340, 333, 361, 358, and 375 d for M1, M2, M3, M4, and TX, respectively, and range in age was about 100 d for most composites. Age of dam was significant for all composites except M4. Linear regressions on age of bull were 0.0376, 0.0379, 0.0308, 0.0410, and 0.0349 cm d−1 for M1, M2, M3, M4, and TX, respectively. Scrotal circumference of composite bulls should be adjusted additively for age of dam and linearly for age of bull. These adjustments tended to be smaller for age of dam and larger for age of bull than those reported for straighbred or purebred bulls. Key words: Beef cattle, composites, scrotal circumference, adjustment factors
Dietary, environmental and microbiological aspects of methane production in ruminants
Authors: McAllister T. A. , Cheng K.-J. , Okine E. K. , Mathison G. W.
Published: March 2010

Methane gas is produced in the rumen by methanogenic bacteria as a metabolic end product. The energy released by bacteria in the process of methane formation can be used for bacterial cell formation. Methane formation acts as an electron sink into which the hydrogen from all ruminal microorganisms drains, allowing a higher yield of adenosine triphosphate. Factors such as the type of carbohydrate in the diet, level of feed intake, digesta passage rate presence of ionophores or lipids in the diet, and ambient temperature influence the emission of methane from ruminants. Methanobrevibacter spp. appear to be the major methanogens in the rumen, but it is likely that phytogenetic analyses will identify new species. The biochemical reduction of carbon dioxide to methane is well defined, and it has been shown that interspecies hydrogen transfer between methanogens and ruminal bacteria prevents the accumulation of reduced nucleotides and the inhibition of feed digestion. The development of strategies to mitigate methane production in ruminants, without causing a negative impact on ruminant production, continues to be a major challenge for ruminant nutritionists and microbiologists. Enhancement of the reduction of carbon dioxide to acetate and direct genetic manipulation of methanogens are two interventions that may further reduce methane losses of ruminants. Key words: Methane, diet, ruminant, microbiology, methanogen
The effect of stevia as a feed sweetener on weight gain and feed consumption of broiler chickens
Authors: Wood D. J. , Lirette A. , Crober D. C. , Ju H. Y.
Published: March 2010

One thousand day-old male chicken broilers housed in 16 floor pens to 42 d of age were used to study the effect of stevia on weight gain and feed consumption. The experimental design was a randomized complete block consisting of four diets (0%, 0.0085%, 0.0425% and 0.085% stevia) each replicated four times. Stevia did not appear to improve feed consumption or weight gain of broilers when used as a feed additive at the concentrations tested in this study. Key words: Broilers, stevia, feed additive, growth performance
Effects of age at photostimulation on reproductive efficiency and carcass characteristics. 2. Egg-type hens
Authors: Robinson F. E. , Wautier T. A. , Hardin R. T. , Wilson J. L. , Newcombe M. , McKay R. I.
Published: March 2010

Increasing day length is the primary cue for the timing of sexual maturation in poultry. Typically, Single Comb White Leghorn (SCWL) pullets are reared under conditions of short days (8L:16D) until 18 wk of age. In this study, the effects of varying the age at photostimulation from 16, 18 or 20 wk of age were studied in terms of carcass composition at photostimulation and at sexual maturity, as well as reproductive performance.A flock of 1600 SCWL pullets (Shaver 288 strain) were housed in floor pens in light-tight facilities (8L:16D). All birds were provided with ad-libitum access to both feed and water. At 16 wk, 18 wk and 20 wk, 50 birds per treatment were moved to laying cages and provided to a photoperiod of 14L: 10D. An additional 288 birds per treatment were housed two birds per cage, and group egg production and feed consumption data were collected to 64 wk of age. At photostimulation (n = 20 birds per treatment) and on the day following the first oviposition, (n = 20 birds per treatment) birds were killed by cervical dislocation. All surviving hens were killed at 64 wk of age. All carcasses were studied in terms of selected organ weights and reproductive organ morphology. Birds killed at photostimulation and at sexual maturity were further studied for whole body carcass composition.Significant differences were found in dry matter, water, lipid and ash content among treatment groups at the age of photostimulation. As age at photostimulation increased, absolute weight of carcass fat, protein and ash increased. The percent carcass lipid content increased for all groups between photostimulation and sexual maturity with the 16 wk treatment group showing the largest increase. The time required to reach sexual maturity from the age of photostimulation decreased as the age at photostimulation increased. No significant differences were found in total egg production. The 16 wk group laid significantly smaller eggs. Delaying sexual maturity until 20 wk of age resulted in an increased prime sequence length and fewer pause days to produce approximately the same number of eggs as birds that were photostimulated at 16 wk of age. Key words: Chicken, egg-type hens, sexual maturity, egg production, carcass composition
Sequence analysis of the β-lactoglobulin locus in Holsteins identifies two new restriction fragment lengtn polymorphisms
Authors: Zhou J. F. , Zadworny D. , Kuhnlein U.
Published: March 2010

The polymerase chain reaction (PCR) was used to amplify and clone a region from the β-lactoglobulin (β-LG) locus that spanned exons IV and V (849 bp). The DNA was amplified from both AA and BB homozygous individuals and sequenced. Sequence analysis revealed that the intervening intron was 673 bp and that three nucleotide substitutions differentiated the A and B forms of β-LG. One of these substitutions was associated with the amino acid substitution (aspartic acid or glycine in the A and B variants, respectively), and the other two which were not reported previously were present in the intron sequence. These nucleotide substitutions resulted in restriction fragment length polymorphisms (RFLPs) that could be used to genotype individuals. The new restriction sites in the intron would result in a more accurate genotyping of the β-LG gene. Animals with B genotype were positive for the presence of two HaeIII restriction endonuclease sites, and type A animals were negative. Animals could also be genotyped on the basis of a polymorphism at a NlaIV restriction site. Genotyping of a random sample of 129 cows and 99 bull calves in Quebec revealed a frequency of 0.66 for the B allele. A comparison between bulls in current use by the artificial insemination industry (n = 114) and from the earliest years of the industry (n = 70) revealed frequencies of 0.58 and 0.56, respectively. Thus, it is unlikely that the sire selection program has affected the allelic frequency. Key words: β-lactoglobulin, Holsteins, DNA sequence, polymorphisms
Salivary vs. serum cortisol for the assessment of adrenal activity in swine
Authors: Cook N. J. , Schaefer A. L. , Lepage P. , Jones S. Morgan
Published: March 2010

The efficacy of salivary cortisol analyses for assessment of the hypothalamic-pituitary-adrenal (HPA) response to stimulation is compared to serum cortisol measurement. Matched samples of serum and saliva were collected from pigs (n = 6) subjected to exogenous adrenocorticotrophic hormone (ACTH) stimulation (i.v. 200 IU) and snaring. Salivary cortisol responses to handling and transport (1 h) were measured in a further 10 pigs. Saliva samples were collected before and after handling and transport. There were significant correlations between serum and salivary cortisol values, following ACTH stimulation (r = 0.8813, P < 0.025), and snaring (r = 0.7964, P < 0.05). The overall ratio of saliva to serum cortisol was 9%. The saliva:serum cortisol ratio was concentration dependent. In pre-stimulation samples the ratio was 8.6% and at maximal concentrations was 13.3%. Handling and transport stress stimulated increases in salivary cortisol concentrations. Differences between pre- and post-transport concentrations were significant (P < 0.0001). Variation in the concentration of cortisol-binding globulin (CBG) is an important factor for the interpretation of adrenal response. Salivary "free" cortisol may be a better indicator of stress than "total" cortisol measured in blood samples. Key words: Saliva, cortisol, pig, ACTH, transport, stress
Effects of dietary protein and potassium contents on plasma urea nitrogen and amino acids in relation to performance of swine
Authors: Cai Yongjiu , Ewan Richard C. , Zimmerman Dean R.
Published: March 2010

Ninty-six 51 kg-pigs were used to determine effects of dietary protein and potassium levels on concentrations of plasma urea nitrogen (PUN) and free amino acids. Pigs were fed four diets containing 13 or 15% of protein and 0 or 0.4% of potassium addition. Gilts took more days to reach an average weight of 110 kg with lower PUN and less backfat than barrows (P < 0.05), but sex did not affect concentrations of plasma free amino acids (P > 0.10). The pigs fed 15% protein diets had higher PUN (P < 0.01) and plasma threonine and isoleucine (P < 0.05), but lower (P < 0.05) plasma lysine, glutamic acid and glycine than pigs fed 13% protein diets. The 0.4% potassium addition resulted in a tendency to increase PUN (P = 0.06) and a decrease in concentrations of plasma alanine, glutamic acid and glycine (P < 0.05). There was an interaction between protein and potassium treatments (P < 0.05) in which plasma lysine concentration decreased with potassium addition to the 13% protein diet but increased with potassium addition to the 15% protein diet. The results indicate that lower PUN concentrations in gilts were associated with improved efficiency of deposition of dietary nitrogen, resulting in improved carcass grade compared with barrows receiving the same dietary treatments. Key words: Plasma urea nitrogen, free amino acids, protein, potassium, pigs
Undegraded intake protein: Effects on milk production and amino acid utilization by cows fed wheat silage
Authors: Baker M. J. , Amos H. E. , Nelson A. , Williams C. C. , Froetschel M. A.
Published: March 2010

Thirty-six Holstein cows in second or later lactation were used in a 63-d completely randomized block design to determine the effects of RUP source on milk production, composition, and estimated AA uptake by the mammary gland. Cows were divided into 12 blocks of three cows each based on DIM (54.5 d) and milk production. Treatments were 1) soybean meal; 2) treated SBM; and 3) supplemental protein from TSBM, corn gluten meal, and Menhaden fish meal with each protein supplying equal amounts of CP. Mean DMI was greater for cows fed supplemental RUP. Intake of RUP was increased by 0.5 and 0.4 kg d−1, respectively, for treatments 2 and 3. The NEL intake was greater for cows fed treatment 3 than for those fed treatment 2. RUP supplementation increased BW accretion and milk production. Milk composition was unaffected except for lactose, which was higher for milk from treatment 3 than for milk from treatment 2. Extraction efficiencies of AA indicated that the supply of Met and Lys to the mammary gland was first and second limiting for cows receiving treatments 1 and 2 but colimiting for cows fed treatment 3. Results indicate performance differences related to RUP sources and specifically the amounts of Lys and Met available for metabolism. Key words: Undegraded protein sources, amino acids, milk yield, dairy cows
The effect of dietary protein source on biochemical indices of stress in stress-susceptible pigs
Authors: Roberts S. A. , Thibault L. , Murray A. C. , Schaefer A. L.
Published: March 2010

The porcine stress syndrome (PSS) is responsible for major economic losses to the swine industry. The present study was performed to determine if 8-wk-old pigs representing each of three genotypes (NN = homozygous noncarrier, Nn = heterozygous carrier, nn = homozygous carrier) with respect to the PSS, differ in selected biochemical indices related to stress (exp. 1), and to examine if these indices are affected during 5 wk of dietary adaptation to a cereal-based swine diet (control diet) or to a feed containing casein, a higher quality protein (exp. 2). The first experiment demonstrated that nn and Nn 8-wk-old female pigs have a significantly greater glycemic response to a blood sampling stressor than do NN female pigs. In contrast, no genotype differences in glycemic response were observed within young male pigs. Pigs of nn genotype also demonstrated a significantly greater plasma dopamine-β-hydroxylase (DBH) activity than did the NN pigs. Results of the second experiment revealed that pigs of the nn and Nn genotypes experienced a greater glycemic response to the initial blood sampling stressor than did the NN pigs. Compared with initial levels, upon the sixth weekly blood sampling stressor the nn and Nn pigs experienced reduced plasma glucose concentration irrespective of diet, while no change in glycemic response was observed in the pigs of the NN genotype. Finally, the DBH activity of the Nn pigs adapted for 2 wk to the casein diet was found to be reduced when compared to control-adapted Nn pigs. This study suggests that in addition to genotype differences, regular exposure to stress combined with dietary adaptation to feed containing a higher quality protein (casein) may confer increased resistance to stress in pigs of the Nn genotype. Key words: Pigs, stress, dietary protein, glycemia, dopamine-β-hydroxylase
The relationship between mineral and nitrogen balances in growing pigs fed diets supplemented with zinc oxide
Authors: Larsen Torben , Poulsen Hanne Damgaard
Published: March 2010

The present study was conducted to determine if there were effects of increasing levels of dietary zinc supplementation on the turnover of zinc and other minerals and trace elements in growing pigs. Thirty crossbred female pigs, with an initial body weight of approximately 25 kg, were randomly assigned to five diets with increasing levels of supplemented zinc (as zinc oxide); i.e. from the intrinsic level of 42 mg kg−1 diet to 72, 105, 170, and 255 mg kg−1, respectively. The animals were subjected to two 7-d balances in metabolic cages, separated by 15 d in pens. Balances consisted of controlled feed intake, i.e. approximately 10% below the expected ad libitum intake, and quantitative collection of feces and urine. Zinc supplementation did not affect nitrogen absorption, excretion, or retention (P > 0.05). The inclusion of zinc oxide did not affect (P > 0.05) weight gain of the animals throughout the 34 d experiment. Neither mineral nor trace element balances, except for zinc, were affected (P > 0.05) by zinc supplementation. Urinary excretion of zinc was not affected (P > 0.05), but zinc absorption and retention calculated in absolute amounts or in proportion to nitrogen retention (i.e. lean body accretion) increased several-fold when diets were supplemented with zinc oxide. Mineral and trace element absorption in proportion to nitrogen retention appeared remarkably constant throughout the experimental period, although feed intake and body size increased with time. Only calcium absorption and retention, determined in proportion to nitrogen retention and as fractions of ingested calcium increased (P < 0.001), 14 and 9%, respectively, with time. In general, mineral and trace element absorption and retention, expressed in proportion to nitrogen retention, appear to be a useful expression for comparisons between observations across time intervals. Key words: Zinc, absorption, retention, interaction, minerals, trace elements