Aalhus, J. L., López-Campos, Ó., Prieto, N., Rodas-González, A., Dugan, M. E. R., Uttaro, B. and Juárez, M. 2014. Review: Canadian beef grading - Opportunities to identify carcass and meat quality traits valued by consumers. Can. J. Anim. Sci. 94: 545-556. Beef value is in the eye, mouth or mind of the consumer; however, currently, producers are paid on the basis of carcass grade. In general, affluent consumers are becoming more discerning and are willing to pay for both credence and measureable quality differences. The Canadian grading system for youthful carcasses identifies both lean yield and quality attributes, whereas mature carcasses are broadly categorized. Opportunities exist to improve the prediction of lean meat yield and better identify meat quality characteristics in youthful beef, and to obtain additional value from mature carcasses through muscle profiling. Individual carcass identification along with development of database systems like the Beef InfoXchange System (BIXS) will allow a paradigm shift for the industry as traits of economic value can be easily identified to improve marketing value chains. In the near future, developing technologies (e.g., grade cameras, dual energy X-ray absorptiometry, and spectroscopic methods such as near infrared spectroscopy, Raman spectroscopy and hyperspectral imaging) will be successfully implemented on-line to identify a multitude of carcass and quality traits of growing importance to segments of the consuming population.

Lee, C. and Beauchemin, K. A. 2014. A review of feeding supplementary nitrate to ruminant animals: Nitrate toxicity, methane emissions, and production performance. Can. J. Anim. Sci. 94: 557-570. The purpose of this review is to discuss the risks and benefits of using supplementary nitrate to reduce enteric methane emissions in ruminants based on the results of a meta-analysis. The meta-analysis confirmed possible nitrate poisoning triggered by higher blood methemoglobin levels with increasing nitrate consumption of ruminants: methemoglobin (%)=41.3×nitrate [g kg^-1 body weight (BW) d^-1] 1.2; R²=0.76, P<0.001. However, acclimatizing animals to nitrate reduced the toxicity of nitrate: methemoglobin (%)=4.2×nitrate (g kg^-1 BW d^-1) 0.4, R²=0.76, P=0.002. Animals fed nitrate reduced enteric methane emissions in a dose-response manner: methane [g kg^-1 dry matter intake (DMI)]=-8.3×nitrate (g kg^-1 BW d^-1) 15.2, R²=0.80, P<0.001. The reduction of enteric methane emissions due to supplementary nitrate was effective and consistent in both in vitro and in vivo studies and also persistent in several long-term studies. Dry matter intake and live weight gain (LWG) of cattle were not affected by nitrate: DMI change, R²=0.007, P=0.65; LWG change, R²=0.03, P=0.31. It is anticipated that supplementary nitrate as a substitute for urea may change urinary nitrogen composition in a manner that increases ammonia and nitrous oxide emissions from manure. Furthermore, supplementary nitrate may have various physiological roles in nitric oxide metabolism in ruminants. In conclusion, supplementary nitrate is a viable means of mitigating enteric methane emissions due to its consistent and persistent efficacy. Risk of toxicity can be lowered by gradual acclimation of animals to nitrate. However, lowered methane production may not re-direct additional metabolizable energy towards animal production.

Durunna, O. N., Block, H. C., Iwaasa, A. D., Thompson, L. C., Scott, S. L., Robins, C., Khakbazan, M. and Lardner, H. A. 2014. Impact of calving seasons and feeding systems in western Canada. I. Postweaning growth performance and carcass characteristics of crossbred steers. Can. J. Anim. Sci. 94: 571-582. Crossbred steers (n=272) weaned from early (EC) and late (LC) calving systems (CS) were used to evaluate the impact of two feeding systems (FS) on postweaning performance and carcass characteristics. The steers were randomly assigned to either a rapid-gain feeding (RF) or a slow-gain feeding (SF) system. The RF steers were managed to have body weight (BW) gain of 1 kg d^-1 on a silage-hay diet during the backgrounding period prior to finishing, while the SF steers were first backgrounded on a hay diet (gain of 0.7 kg d^-1), then grazed alfalfa-meadow bromegrass pasture and annual cereal swaths prior to finishing. All treatment groups received a conventional diet during finishing until the steers attained a target backfat thickness or BW or both. There was no difference (P=0.48) between the two FS for the average age of the steers at the beginning of the experiment. There was a CS×FS effect (P<0.01) on the age at slaughter, where the steers in the EC-RF, EC-SF, LC-RF and LC-SF were 426, 659, 504 and 606 d, respectively. The longer time on feed for LC-RF steers compared with EC-RF suggests the potential effect of summer ambient temperatures at finishing. The EC-RF group had the least carcass fat thickness (P<0.01), but there was no main or interaction effect (P>0.08) on dressing percentage or lean meat yield. There was a FS effect (P<0.05) on meat colour and marbling texture where SF steers had more desirable meat colour and marbling texture. Beef producers adopting EC-RF would finish their calves earlier but at a lighter weight.

Durunna, O. N., Block, H. C., Iwaasa, A. D., Scott, S. L., Robins, C., Khakbazan, M., Dugan, M. E. R., Aalhus, J. L., Aliani, M. and Lardner, H. A. 2014. Impact of calving seasons and feeding systems in western Canada. II. Meat composition and organoleptic quality of steaks. Can. J. Anim. Sci. 94: 583-593. Fatty acid profiling, meat and organoleptic quality assessments were conducted on 160 carcasses of crossbred steers born into one of two calving systems and later assigned to one of two postweaning feeding systems. The steers were weaned from either an early calving or late calving system and later assigned to either a rapid-gain feeding (RF) or a slow-gain feeding (SF) system. The RF steers received a silage-hay diet during the backgrounding period prior to finishing, while the SF steers received a hay diet at backgrounding and then grazed alfalfa-meadow bromegrass pasture and annual cereal swaths prior to finishing. All treatment groups received a conventional diet during finishing until the steers attained a target backfat thickness or body weight. Fatty acid analyses were conducted on longissimus dorsi muscle (LDM) and subcutaneous fat samples. Other analyses included LDM composition, tenderness and taste panel evaluations. Total saturated fatty acid was greater (P<0.02) in samples from RF steers, while total monounsaturated fatty acid was greater (P<0.01) in SF steers. The SF steers had greater (P<0.01) conjugated linoleic acid concentration. There was no main or interaction effect (P>0.05) on beef aroma, flavour and tenderness but the SF steaks had lower (P=0.02) cooking losses than RF steaks. The SF strategy has the potential to create a value chain that would lead to finished steers with higher backfat omega-3, conjugated linoleic acid and trans vaccenic acid and less cooking moisture losses.

Zhu, Z., Chen, Y., Huang, Z., Zhang, Y., Xu, Q., Tong, Y., Zhai, F., Chang, G. and Chen, G. 2014. Effects of transport stress and rest before slaughter on blood parameters and meat quality of ducks. Can. J. Anim. Sci. 94: 595-600. Ducks have been transported to be slaughtered at centralized locations since the 2013 avian influenza A (H7N9) epidemics in China. It is unavoidable that a certain amount of stress will occur during the transportation. We investigated the effects of transport stress and rest before slaughter on blood parameters and meat quality in ducks. Pekin ducks (42 d old) were randomly divided into six groups. Each group had five replicates, with four ducks in each replicate. The experimental design included the variables transport time and rest time before slaughter. Transport distance categories were short-distance (1 h transport; n=20), medium-distance (2 h transport; n=20) and long-distance (3 h transport; n=20) transport. Rest time was categorized as short (0.5 h; n=20) or long (2 h; n=20) periods of rest. Blood samples and meat samples were collected after transport or after the post-transport rest period. Blood indicators (triiodothyronine, thyroxine, insulin, glutamic-pyruvic transaminase, aspartate transaminase, creatine kinase, and glutathione peroxidase) were measured using enzyme-linked immunosorbent assay (ELISA) kits. Meat quality characteristics (meat component, pH, malondialdehyde, and protein carbonyl) were also measured. Triiodothyronine, thyroxine, aminotransferase, glutamic-oxaloacetic transaminase, creatine kinase, glutathione peroxidase, pH, malondialdehyde, and protein carbonyl values changed significantly in ducks exposed to the medium-distance transport treatment. Stress indicators improved and meat quality returned to normal by the end of a 2-h pre-slaughter rest. These results indicate that a 2-h transport causes serious stress in ducks. A 2-h rest before slaughter mitigates these adverse effects.

Wysokinska, A. and Kondracki, S. 2014. Assessment of changes in sperm cell membrane integrity occurring during the storage of semen from genetically different males using two diagnostic methods. Can. J. Anim. Sci. 94: 601-606. The present study was carried out to assess changes in sperm cell membrane integrity occurring during the storage of semen collected from genetically different domestic male pigs. The study was aimed at assessing differences in the course of changes in the integrity of cell membranes in spermatozoa produced by males with different degrees of genetic diversity (pure-bred males, two-breed hybrids and multi-breed crosses) and testing the usefulness of two methods of sperm cell membrane integrity evaluation, based on material collected from genetically different males. The experiments were conducted on 56 ejaculates collected from 28 domestic male pigs. The examination of sperm cell membrane integrity was performed three times for each ejaculate, i.e., after 1 h, after 24 h and after 48 h from collection. The preparations for analysing cell membrane integrity were made using two methods: the SYBR 14/PI method and the eosin-nigrosin method. It was found that both SYBR 14/PI and eosin-nigrosin staining methods make it possible to successfully assess the integrity of the plasma membrane of domestic pig sperm cells under in vitro conditions. Hybrid pig spermatozoa, especially those from multi-breed crosses, better retain the integrity of their plasmalemmas than the spermatozoa of pure-bred boars. The ejaculates of Hypor cross-breed boars assessed after 1, 24 and 48 h of storage contain more spermatozoa with intact cell membranes than the ejaculates of pure-bred Duroc and Pietrain boars. The ejaculates of Hypor boars also show fewer decaying spermatozoa than those produced by pure-bred boars.

López-Campos, Ó., Aalhus, J. L., Larsen, I. L., Juárez, M. and Basarab, J. A. 2014. Effects of production system and growth promotants on the physiological maturity scores in steers. Can. J. Anim. Sci. 94: 607-617. Over a 2-yr period, 224 crossbred steers were allotted to a 2×2×2 factorial arrangement of treatments to determine the effect of the production system (calf-fed vs. yearling-fed), growth implant strategy (non-implanted vs. implanted) and β-agonist supplementation (no ractopamine vs. ractopamine) on physiological indicators of maturity. Dentition and ossification scores along the vertebral column were collected post-mortem during head inspection and grading. Dentition score was significantly affected (P<0.001) by production system, but not by implant (P=0.68) or β-agonist (P=0.31). There were significant interactions (P<0.001) between production system and implant strategy on the frequencies of carcasses showing ossification in the thoracic, lumbar and sacral vertebral processes. There was a significant interaction (P<0.0001) between the production system and implant strategy on the frequencies of the carcasses considered as <21 or >21 mo of age based on a segregation model using only physiological maturity assessments. These data emphasize the inability of physiological scores to accurately reflect chronological age, with overall classification accuracies of 0.68 and 0.53 for dentition and ossification scores. The highest overall classification accuracies were obtained using the thoracic (0.74) or lumbar (0.69) ossification scores. Implants accelerate the ossification process, particularly in younger animals, thus having a dramatic effect on numbers of animals eligible to be categorized as <21 mo of age based on physiological maturity evaluation.

Zhang, L., Wang, Y.-y., Fu, M.-z., Li, G., An, N., Li, S.-y. and Zhou, Z.-q. 2014. The effects of ovariectomy on meat performance and expression of GH/IGF-I in young goats. Can. J. Anim. Sci. 94: 619-626. Experiments were carried out to investigate the effects of ovariectomy on meat production efficiency and to explore the expression of GH/IGF-I in young goats. Animal performance, meat quality, levels of serum growth hormone (GH) and insulin-like growth factor 1 (IGF-I), and mRNA levels of three key genes [GH Receptor (GHR), IGF-I and IGF-I Receptor (IGF-IR)] in longissimus dorsi and biceps femoris muscles were measured. The results show that carcass weight, net meat mass, fat weight and loin eye area of ovariectomized goats were higher than those of the controls, and ovariectomized goats lost 0.40 kg of bone weight (P<0.05). There was no statistically valid difference for the color, pH, water-holding capacity, or cooking rate of meat (P>0.05) between the two groups, except for the shear value, which was significantly lower in the Ovx group than in the control group (P<0.05). The results of this research show for the first time a significant trend (P<0.05) for serum GH and IGF-I in the direction of increasing in ovariectomized goats. Furthermore, the mRNA levels of GHR, IGF-I and IGF-IR in muscle were all up-regulated, except for the IGF-I gene in biceps femoris, by ovariectomy. In summary, ovariectomy showed a beneficial promotion in animal performance, but did not reduce meat quality, and increased serum GH and IGF-I and mRNA expression levels of GHR, IGF-I and IGF-IR in young female goats.

Pouliot, E., Gariépy, C., Thériault, M. and Castonguay, F. W. 2014. Use of electrical stimulation and chilling to enhance meat tenderness of heavy lambs. Can. J. Anim. Sci. 94: 627-637. The aim of this study was to determine if electrical stimulation and chilling can modulate pre-rigor pH-temperature dynamics in order to enhance meat tenderness of heavy lambs produced in Quebec and determine if there is an optimum carcass temperature window to reach pH 6.0. A total of 128 heavy lambs (fasted body weight between 38 and 52 kg) were selected at the abattoir over 8 slaughter days (16 lambs d^-1) and assigned to four processing treatments in a 2×2 factorial design: electrical stimulation (ES) or not (NES) and normal (NC) or slow (SC) chilling. Slow-chilled carcasses stayed warmer during the first 12 h postmortem (P<0.001), but reached the same temperature as NC ones thereafter. They also had a lower pH between 2 and 12 h (P<0.05). Stimulated carcasses had a lower pH than NES throughout the first 24 h postmortem (P<0.001), while ultimate pH was similar (P=0.738). Shear force values were improved (P<0.001) by both ES and aging as expected, although chilling had no effect (P=0.400). Stimulation×aging interactions for shear force values (P=0.019) and myofibrillar fragmentation index (P=0.097) indicate that aging began earlier following ES. Sarcomeres were longer for ES compared with NES carcasses (P<0.001) indicating that the latter were subject to cold shortening. Meat from NES carcasses was more prone to be tough, although an important part of NES carcasses provided tender meat. This illustrates the importance of individual variations on tenderness and the multiplicity of factors involved in its development. No optimal window was observed for temperature at pH 6.0.

Martínez, S., Valera, L., Villodre, C., Madrid, J., Orengo, J., Tvarijonaviciute, A., Cerón, J. J. and Hernández, F. 2014. Effect of feeding on hormones related with feed intake in reproductive sows with different energy balances. Can. J. Anim. Sci. 94: 639-646. The different phases that occur during the reproductive life of the sow involve different energy balances, which can affect the levels of hormones that regulate appetite. This study analyzes the behaviour of serum insulin, leptin, ghrelin, cortisol and butyryl-cholinesterase, before and after feeding in pregnant, lactating and post-weaning sows. Hormones were analyzed in blood samples, which were collected after fasting overnight (0 min) and 30 min after feeding at day 109 of pregnancy, at day 9 post-farrowing and at day 3 post-weaning. Before feeding, insulin and leptin levels were not statistically different between reproductive stages. Feeding increased serum insulin and leptin levels of pregnant sows, increased insulin and decreased leptin levels in lactating sows, but had no effect on post-weaning sows. Deacylated ghrelin was higher in pregnant sows and acylated ghelin in post-weaning sows before feeding. Feeding intake did not affect the concentration of deacylated and acylated ghrelin in any group. Cortisol was positively correlated with acylated ghrelin before feeding in pregnant and lactating sows, and negatively with deacylated ghrelin before and after feeding in pregnant sows. There was a negative correlation between deacylated and acylated ghrelin before and after feeding in pregnant and post-weaning sows. So, sows with different energy balances had different insulin, acylated ghrelin and cortisol dynamics before and after feeding, suggesting that these analytes could be used as biomarkers to detect situations resulting in a poor energy balance in order to improve handling programs.

Brauner, C. C., Menezes, L. M., Lemes, J. S. and Pimentel, M. A. 2014. Differences between reproductive traits in beef bulls used for multiple-sire breeding under range conditions. Can. J. Anim. Sci. 94: 647-652. The aim of this study was to evaluate the reproductive traits (scrotal circumference and semen quality) of different breeds of beef bulls used for multiple-sire breeding under range conditions, as well as to verify the relation between four sperm concentration scores and the reproductive traits of beef bulls. Two hundred and one bulls of three different breeds (Angus, Nelore and Brangus) and three different age groups (18, 24 and 36 mo old) were evaluated. Angus showed better (P>0.05) reproductive traits than Brangus and Nelore bulls, in which scrotal circumference, mass motility spermatozoa, motility spermatozoa, as well as spermatic vigor were greater than those of other breeds. Two-year-old bulls demonstrated better reproductive traits as compared with the other age groups. The sperm concentration score had a linear effect (P<0.01) on all reproductive traits evaluated, and the same evidence was also detected for body weight. It was concluded that genetic groups should be considered differently for multiple-sire breeding under range conditions, especially because Bos taurus and Bos indicus have significant reproductive trait differences. Moreover, the sperm concentration score can be used as an auxiliary method of semen quality in beef bulls, having a positive relation with other breeding soundness evaluation traits.

Michalek, K., Dratwa-Chalupnik, A., Ciechanowicz, A. K. and Malinowski, E. 2014. Aquaporin 2: Identification and analysis of expression in calves' urine during their first month of life. Can. J. Anim. Sci. 94: 653-659. Aquaporin 2 (AQP2) is a vasopressin-regulated water channel of the renal collecting duct and is excreted into urine. Renal excretion of AQP2 has been studied in humans, dogs, rats and mice. The aim of this study was to identify and analyze expression of AQP2 in calves' urine. Short and controlled diarrhea was induced in the calves in order to determine any change in renal excretion of AQP2 and to evaluate a possible role of this channel in water balance during the neonatal period. For this purpose, an additional portion of lactose was administered to the calves with a milk replacer. The present work shows that after transient diarrhea associated with excessive supply of lactose in the diet, a significant increase in renal AQP2 excretion was reported in the first 3 wk of the calves' lives. Renal excretion of this protein in the urine increased significantly despite the absence of changes in the concentration of vasopressin or the osmotic pressure of the blood plasma. The increase observed in the expression of the protein might be associated with the reduction of the total Ca² concentration in the blood plasma of calves. The results clearly indicate a different mechanism regulating urinary excretion of AQP2 in newborn calves, hitherto unknown. Although elevated renal excretion of AQP2 was observed, there was no increase in the osmolality of the urine in the calves tested.

Liu, J. B., Chen, D. W. and Adeola, O. 2014. Casein supplementation does not affect true phosphorus digestibility and endogenous phosphorus loss associated with soybean meal for broiler chickens determined by the regression method. Can. J. Anim. Sci. 94: 661-668. Cornstarch-based semi-purified diets impair growth performance of birds when using the regression method to estimate phosphorus (P) digestibility in assay feed ingredient. Therefore, casein is usually supplemented in the basal diet to improve dietary amino acid profile. The objective of this study was to investigate the influence of dietary casein supplementation on regression-derived estimates of true phosphorus digestibility and endogenous phosphorus loss (EPL) associated with soybean meal (SBM) in broiler chickens. Four hundred thirty-two male Ross 708 broilers were allocated to nine diets in a 3×3 factorial arrangement of three diet types (with casein at moderate dietary P, without casein at moderate dietary P, or without casein at low dietary P) and three SBM levels (low, medium, or high). There were six birds per cage and eight replicate cages per diet in a randomized complete block design. The birds were fed experimental diets from day 12 to 20 post-hatching. Chromic oxide was used as an indigestible marker to calculate P digestibility and retention. The results indicated that body weight gain and feed efficiency linearly increased (P<0.01) and dry matter retention was linearly decreased (P<0.01) with the addition of SBM, regardless of diet type. The apparent prececal P digestibility and excreta P retention were increased by casein supplementation (P<0.01). The prececal and excreta P output linearly increased (P<0.01) with graded inclusion of SBM in each diet type. Regression of P output against dietary P intake showed that the type of diets (with casein at moderate dietary P, without casein at moderate dietary P, or without casein at low dietary P) had no effect on true prececal P digestibility and excreta P retention, or EPL associated with SBM for broiler chickens (P>0.05). In conclusion, the results of the current study indicate that adding casein, which is high in P digestibility, to cornstarch-based basal diets does not affect the estimation of EPL or true P digestibility and retention associated with SBM for broiler chickens using the regression method.

Classen, H., Cho, M., Hucl, P., Gomis, S. and Patterson, C. A. 2014. Performance, health and tissue weights of broiler chickens fed graded levels of hairless hulled yellow and brown canary seed (Phalaris canariensis L.). Can. J. Anim. Sci. 94: 669-678. Research examined the effects of dietary levels (0, 15, 30 and 45%) of hulled yellow (C05041) and brown (CDC Maria) canary seed on the performance and health of broiler chickens. Eight (six birds each) and five (four birds each) replications per treatment were used from 0 to 21 and from 22 to 35 d of age, respectively. Growth rate and feed intake were affected in a quadratic manner by canary seed level from 0 to 21 d with the highest growth achieved by 15 and 30% treatments, but were not affected from 22 to 35 d. Feed to gain ratio decreased linearly with increasing canary seed for both 0- to 21-d and 22- to 35-d time periods. Mortality was not affected by level of canary seed, but more birds fed the C05041 cultivar died as a result of yolk sac infection and infectious causes than did birds fed CDC Maria. Level of canary seed affected jejunum, kidney and bursa of Fabricius proportional weights in a quadratic manner with no differences between the 0 and 45% treatments. No interactions were found between dietary level and cultivar of canary seed. Treatment did not affect gross necropsy at trial end or histopathology of key organs. Yellow and brown hairless canary seed has merit and is safe for poultry feeding.

Zhang, X., Ding, Y., Qu, M. and Lu, D. 2014. Beneficial effects of ruminal oligosaccharide administration on immunologic system function in sheep. Can. J. Anim. Sci. 94: 679-684. Oligosaccharides (Os) are considered prebiotics with potential beneficial immunomodulating effects, although little is known about their effects in ruminants. Therefore, the objective of this study was to investigate the effects of Os administration on sheep immunologic system function. Sheep were randomly allotted into three different treatment groups (three sheep each): (1) control, infused with equal volume of vehicle distilled water; (2) medium level, infused with 5.4 g Os d^-1 (0.6% of basal diet); (3) higher level group, infused with 10.8 g Os d^-1 (1.2% of basal diet). The study comprised three experimental stages, each with a 14-d adaptation period and a 21-d experimental period; Os were administered during each experimental period via cannulae placed in the rumen, duodenum or ileum, respectively. At 7, 14 and 21 d of infusion, the proportion of circulating CD4 and CD8 T-lymphocytes was assessed via flow cytometry, and serum IgA/IgG concentrations were analyzed using an ELISA test. The Os infusion increased (P<0.05) the proportion of CD4 T-lymphocytes hence raising the CD4 /CD8 ratio, as well the serum concentrations of IgA and IgG. Interestingly, ruminal infusion yielded the best results, while ileal administration resulted in negative measurements. These findings may be useful to elucidate the cellular and molecular mechanisms responsible for enhanced immune functions in sheep receiving dietary supplementation with indigestible oligosaccharides.

Meale, S. J., Ding, S., He, M. L., Dugan, M. E. R., Ribeiro Jr. G. O., Alazzeh, A. Y., Holo, H., Harstad, O. M., McAllister, T. A. and Chaves, A. V. 2014. Effect of Propionibacterium freudenreichii on ruminal fermentation patterns, methane production and lipid biohydrogenation of beef finishing diets containing flaxseed oil in a rumen simulation technique. Can. J. Anim. Sci. 94: 685-695. The objectives of this study were to examine the effects of Propionibacterium freudenreichii (strain T54; PB) and flaxseed oil (FO) in a total mixed ration on ruminal fermentation, CH₄ production and fatty acid biohydrogenation in two artificial rumens (RUSITEC). The experiment consisted of 8 d of adaptation and 12 d of sample collection with four replicate fermenters per treatment. Treatments were: (1) CON; (2) PB; (3) FO (60 g kg^-1 DM with autoclaved PB); (4) FOPB (60 g kg^-1 DM with PB). Disappearance of DM (g kg^-1 DM) and gas production (mL g^-1 DM) were not affected by treatment (P>0.05). Inclusion of FOPB increased (P=0.01) total volatile fatty acid (VFA) production (mmol d^-1), compared with CON and PB. The acetate:propionate ratio was reduced (P<0.001) in all treatments, compared with CON. Methane production (mL g^-1 DM or mL g^-1 DMD) was lowest (P<0.001) with PB (27.1%); however, FO (14.3%) and FOPB (19.3%) also reduced CH₄ compared with CON. Fatty acid profiles for PB were similar (P>0.05) to CON for most fatty acids. Concentrations of 18:3n-3 were greater (P<0.001) in FO and FOPB in both digesta and effluent, compared with CON. Propionibacterium freudenreichii had very little effect on ruminal biohydrogenation, but reduced CH₄ production under the current conditions as a result of increasing propionate production.

Lynch, J. P., Prema, D., Van Hamme, J. D., Church, J. S. and Beauchemin, K. A. 2014. Fiber degradability, chemical composition and conservation characteristics of alfalfa haylage ensiled with exogenous fibrolytic enzymes and a ferulic acid esterase-producing inoculant. Can. J. Anim. Sci. 94: 697-704. This study investigated the effects of two fibrolytic enzyme products, applied at baling alone or in combination with a ferulic acid esterase-producing bacterial additive, on the ensilage dynamics, chemical composition and digestibility of alfalfa haylage. Five replicate wrapped bales were produced with one of five treatments, including an untreated control, and one of two fibrolytic enzyme products (EN1 and EN2) applied either alone or in combination with a ferulic-acid producing bacterial additive (FAEI). No effect of treatment was observed on the neutral detergent fiber (NDF) (P=0.889) or acid detergent fiber (ADF) (P=0.065) concentrations of haylage after ensilage, but haylage produced using fibrolytic enzyme products underwent greater (P<0.018) increases in temperature following exposure to aerobic conditions. Haylages produced with fibrolytic enzyme products had a greater (P<0.001) in vitro NDF degradability (NDFD) than untreated haylage. The use of fibrolytic enzymes applied to alfalfa haylage at ensiling increased the NDFD, despite minimal effects on the chemical composition of the herbage. However, the greater aerobic deterioration of fibrolytic enzyme-treated bales indicates higher dry matter losses during aerobic exposure. The use of FAEI with fibrolytic enzymes did not further enhance the effects of fibrolytic-enzyme treatments.

Arroquy, J. I., Cornacchione, M. V., Colombatto, D. and Kunst, Jr., C. 2014. Chemical composition and in vitro ruminal degradation of hay and silage from tropical grasses. Can. J. Anim. Sci. 94: 705-715. This study was conducted to evaluate the effects of preservation type on chemical composition and in vitro ruminal degradation of warm-season grasses (WSG). Treatments consisted of two factors (6×2): the first factor was tropical grasses: Cenchrus ciliaris (cv. Biloela, and cv. Molopo), Chloris gayana (cv. Callide and cv. Finecut), Panicum maximum, and Brachiaria bryzanta; and the second factor was preservation type (hay vs. silage). Cell wall, hemicellulose, cellulose, and water-soluble carbohydrate (P<0.05) concentrations were different among WSG. In general, hay or silage altered fiber content compared with fresh. For instance, hemicellulose and cellulose contents were lower in silage than in hay and fresh grass (P<0.05). Gas production rates were higher in silage from 0 to 24 h of fermentation, except at 4 h of incubation. After 24 h, gas production (GP) rate was similar for both preservation types, whilst potential GP was similar between preservation types. However, silage had decreased lag time compared with hay (P<0.01). Silage had greater dry matter disappearance than hay (P<0.05), and gas production yield was similar for grass species and preservation type. Our results indicate that WSG conserved as silage showed beneficial changes in chemical composition and dry matter degradation compared with hay.

Beiranvand, H., Khorvash, M., Ghorbani, G. R., Homayouni, A., Bachmann, L. and Kargar, S. 2014. Evaluation of ketogenic vs. glucogenic substrates as energy sources in starter diets for Holstein dairy calves. Can. J. Anim. Sci. 94: 717-723. The objective of this study was to investigate the influence of the inclusion of granular sugar and sodium propionate as ketogenic and glucogenic substrates, respectively, in calf starter diets on the performance, weaning age, rumen fermentation characteristics and plasma β-hydroxybutyrate (βHBA). Twenty-one newborn male Holstein calves were housed in individual pens until 10 wk of age, receiving starter ad libitum, fresh water free choice, and fed four liters of pasteurized waste milk daily until weaning. Calves were randomly assigned to one of the following treatments: (1) no supplemental additive (Control); (2) granular sugar (5% of dietary DM; Sugar); and (3) sodium propionate (5% of dietary DM; Propionate). Overall, no differences were observed among treatments for starter intake, average daily gain, feed efficiency, day of weaning, body weight at weaning and at the end of the study. Body measurements including body length, hip height, hip width, and heart girth were remained unchanged among treatments. Ruminal fluid pH (5.36 to 5.58) and concentrations of total volatile fatty acids (93.1 to 101.6 mM), acetate (43.6 to 53.1 mM), propionate (30.5 to 35.1 mM), and ratio of acetate to propionate (1.42 to 1.89) were not affected by treatments over the experimental period. However, the concentration of butyrate was greater at 35 and 70 d of age in calves receiving Sugar compared with calves receiving Propionate, but not compared with the Control. Greater blood βHBA at 45, 60 and 70 d of age was noticed in calves fed Sugar compared with those fed Control and Propionate. In conclusion, according to the concentrations of supplemental ketogenic and glucogenic substrates used in the current experiment, sugar and sodium propionate in starter diets did not improve calf performance.

Yang, W. Z., Oba, M., Swift, M. L. and McAllister, T. A. 2014. Short Communication: Variation in response to processing, in vitro gas production and fermentation of western Canadian feed barley. Can. J. Anim. Sci. 94: 725-729. Sixty feed barley samples were collected from various locations in western Canada. Samples were either ground (1 mm) or dry-rolled to a processing index of 80%, and fermentability was assessed by measuring gas production (GP) and dry matter disappearances (DMD) at 0, 4, 8, 14 and 24 h of incubation using a batch culture technique. Physical and chemical composition, and GP and DMD varied substantially among samples. There were significant correlations among test weight and nutrient content of barley with GP and DMD of ground barley. The results indicate that the impact of nutrient content on in vitro DMD is more easily detected with ground than rolled barley.

Nanon, A., Suksombat, W., Beauchemin, K. A. and Yang, W. Z. 2014. Short Communication: Assessment of lemongrass oil supplementation in a dairy diet on in vitro ruminal fermentation characteristics using the rumen simulation technique. Can. J. Anim. Sci. 94: 731-736. A study using a rumen simulation technique (Rusitec) was conducted to investigate the effect of increasing lemongrass oil (LMO) supplementation on ruminal fermentation characteristics of a dairy cow diet. Increasing LMO from 0, to 100 to 200 mg kg^-1 dry matter did not affect volatile fatty acid concentration, whereas LMO supplementation increased large and small peptide N and reduced ammonia N concentration. Adding 200 mg of LMO kg^-1 dry matter also increased microbial N production. However, feed digestibility was not affected by LMO supplementation. These results suggest that the addition of LMO may inhibit deamination in the rumen.

Duplessis, M., Girard, C. L., Santschi, D. E. and Pellerin, D. 2014. An economic model evaluating the supplementation of folic acid and vitamin B₁₂ given around parturition and in early lactation on dairy farms in Québec, Canada. Can. J. Anim. Sci. 94: 737-747. The aim of this study was to estimate the potential profitability of a combined supplement of folic acid and vitamin B₁₂ given around parturition and in early lactation in commercial dairy herds in Québec. A total of 791 dairy cows from 14 herds were enrolled. Cows were assigned to weekly intramuscular injections of saline or 320 mg of folic acid and 10 mg of vitamin B₁₂. Treatments began 3 wk before the expected calving date and lasted until 8 wk of lactation. Within each herd, data on production, reproduction, and incidence of metabolic disorders and other diseases were recorded. With regard to the Canadian dairy industry, which operates under a supply management system, two scenarios were studied: (1) quota kept constant and (2) number of cows kept constant. For scenarios 1 and 2, eight and seven herds out of 14, respectively, obtained a positive annual net margin per cow following the vitamin supplement. The average net margins were Can$31.18 and Can$-4.86 N cow^-1 yr^-1 for scenarios 1 and 2, respectively. The variability of the response highlights that supplies of these vitamins by ruminal synthesis were probably different among herds and actual knowledge does not allow predicting supplies according to the diet.