Karisa, B. K., Thomson, J., Wang, Z., Bruce, H. L., Plastow, G. S. and Moore, S. S. 2013. Candidate genes and biological pathways associated with carcass quality traits in beef cattle. Can. J. Anim. Sci. 93: 295-306. The objective of this study was to use the candidate gene approach to identify the genes associated with carcass quality traits in beef cattle steers at the University of Alberta Ranch at Kinsella, Canada. This approach involved identifying positional candidate genes and prioritizing them according to their functions into functional candidate genes before performing statistical association analysis. The positional candidate genes and single nucleotide polymorphisms (SNP) were identified from previously reported quantitative trait loci for component traits including body weight, average daily gain, metabolic weight, feed efficiency and energy balance. Positional candidate genes were then prioritized into functional candidate genes according to the associated gene ontology terms and their functions. A total of 116 genes were considered functional candidate genes and 117 functional SNPs were genotyped and used for multiple marker association analysis using ASReml^®. Seven SNPs were significantly associated with various carcass quality traits (P=0.005). The significant genes were associated with biological processes such as fat, glucose, protein and steroid metabolism, growth, energy utilization and DNA transcription and translation as inferred from the protein knowledgebase (UniprotKB). Gene network analysis indicated significant involvement of biological processes related to fat and steroid metabolism and regulation of transcription and translation of DNA.

Zwambag, A., Kelly, M., Schenkel, F., Mandell, I., Wilton, J. and Miller, S. 2013. Heritability of beef tenderness at different aging times and across breed comparisons. Can. J. Anim. Sci. 93: 307-312. The heritability of shear force at 7, 14 and 21 d was estimated from a crossbred population of beef cattle. The population consisted of approximately 1400 crossbred cattle that were predominantly the offspring of Angus, Simmental, Gelbvieh and Piedmontese sires bred to predominantly Angus and Simmental females. Significant breed effects on tenderness were found within each aging time and no effect of heterosis was detected. The heritability of shear force declined from 0.194 to 0.048 as aging time increased from 7 to 21 d, highlighting the effectiveness of aging as a tool to improve tenderness. The repeatability of shear force was also found to be moderate (0.53). However, as energy prices increase it may be attractive to reduce aging times, thus breeding animals that are more tender at shorter aging times would be beneficial. The heritability of tenderness found at shorter aging times would indicate that improvement in this trait would be possible within a population where phenotypes are available.

Yang, S.-l., Li, A.-P., Xu, L.-x. and Yang, H. 2013. Short Communication: Mitochondrial DNA D-loop sequence diversity and origin of Chinese pony breeds (Equus caballus). Can. J. Anim. Sci. 93: 313-319. Previous studies based on mitochondrial DNA (mtDNA) data have shown that Chinese horses have high genetic diversity. However, little is known about the genetic diversity of mtDNA D-loop sequences and maternal origin of five Chinese pony breeds. In the present study, genetic diversity of 343-bp D-loop sequences for136 individuals representing five Chinese pony breeds was analyzed. To address the question of the single and multiple maternal origin of Chinese pony populations, 13 partial mtDNA D-loop reference sequences from GenBank representing eight ancient and modern horse breeds (Connemara, Garrano, Sorraia, Pottok, Losino, Cheju, Tuva and a Swedish horse) were added to conduct the phylogenetic analyses. A total of 59 haplotypes and 50 polymorphic loci were detected, the haplotype diversity (h) ranged from 0.894 to 0.947 and nucleotide diversity (p) ranged from 0.0184 to 0.0229, suggesting relatively abundant genetic diversity in the Debao, Yunnan and the Guizhou breeds. The phylogenetic tree and median-joining network show multiple maternal origins of the five Chinese pony breeds.

Tian, J.-C., Han, L., Yu, Q.-L., Shi, X.-X. and Wang, W.-T. 2013. Changes in tenderness and cathepsins activity during post mortem ageing of yak meat. Can. J. Anim. Sci. 93: 321-328. Very little research has been conducted on yak meat tenderization. In this study we investigated the changes in physical characteristics (e.g., pH, water-holding capacity, texture profile analysis, shear force) and cathepsins L, B and H activities in the tenderization process. These traits were quantified in longissimus dorsi muscle from 10 yaks during 192 h post mortem. Samples were aged at 4°C for 0, 12, 24, 36, 48, 72, 120, 168 and 192 h. pH decreased (P<0.05) from 6.84 to 5.54 in the first 72 h and did not change significantly during the next 120 h. Water-holding capacity showed an overall decreasing trend (P<0.05). Shear force decreased? (P<0.05) and myofibrillar fragmentation index increased? (P<0.05), and it was concluded that ageing can improve yak meat tenderness. Our results on texture profile analysis showed a decrease in hardness (P<0.05), springiness (P<0.05) and chewiness (P<0.05), reflected in a progressive softening during ageing (P<0.05). Cathepsins L, B and H activity showed an increased trend (P<0.05). In conclusion, our results show potential roles for cathepsins L, B and H in the tenderization process. This study provides further insights into the tenderization process of yak meat, which may ultimately be used for the advantageous manipulation of the process.

Cook, N. J., Hayne, S. M., Rioja-Lang, F. C., Schaefer, A. L. and Gonyou, H. W. 2013. The collection of multiple saliva samples from pigs and the effect on adrenocortical activity. Can. J. Anim. Sci. 93: 329-333. The validity of collecting multiple saliva samples for the measurement of cortisol was tested in two sampling regimes in two weight classes of grower pigs (50 and 100 kg). The sampling regimes were a high-frequency, short-duration (HFSD) protocol involving collection of multiple samples within approximately 2 min of each other over a period 30 min. The second regime was a low-frequency, long-duration (LFLD) protocol in which samples were collected every 30 min for 3 h. Both sampling regimes were applied to individually housed pigs. The effect of repeated sampling of a focal pig on its cohorts in a group-housed pen was tested using the LFLD regime. There was no evidence of an effect of either of the sampling protocols on salivary cortisol concentrations in individually housed or group-housed pigs. There was some evidence that higher concentrations of salivary cortisol were associated with longer individual sampling durations in the HFSD regime for animals in the 50-kg weight class but not in the 100-kg weight class. The evidence from these experiments indicates that the collection of multiple saliva samples does not affect salivary cortisol concentrations in grower pigs, but that collection of individual samples in as short a time as possible would be prudent to avoid sampling effects in younger animals.

Almeida, F. N., Htoo, J. K., Thomson, J. and Stein, H. H. 2013. Amino acid digestibility in camelina products fed to growing pigs. Can. J. Anim. Sci. 93: 335-343. Camelina seed production has increased in North America because of demand for camelina oil for biofuel production. Camelina expellers (CE) is the co-product that remains after oil has been expelled, and CE usually contains approximately 35% crude protein (CP), 14% ether extract, 10% crude fiber, and 5% ash making it an attractive feedstuff for livestock. An experiment was conducted to determine the standardized ileal digestibility (SID) of CP and amino acids (AA) in two sources of camelina seeds [CS-1 and CS-2; average: 39% acid hydrolyzed ether extract (AEE), 28% CP, 27% neutral detergent fiber (NDF), 12% acid detergent fiber (ADF), 4% ash] and in three sources of CE (CE-1, CE-2, and CE-3; average: 35% CP, 24% NDF, 15% AEE, 14% ADF, 6% ash) and to compare the SID of CP and AA in camelina products with the SID of CP and AA in solvent-extracted canola meal fed to pigs. Seven growing pigs (initial BW 43.5 kg) were randomly allotted to a 7×7 Latin square design with seven diets fed to individually housed pigs over seven periods. Six of the diets contained CS, CE, or canola meal as the sole source of CP and AA and a N-free diet was used to determine basal endogenous losses of CP and AA. The SID of CP in CS-1 and CE-2 was less (P<0.01) than the SID of CP in canola meal, but the SID of CP in CS-2, CE-1, and CE-3 was not different from the SID of CP in canola meal. The SID of Lys in CS-1 and CS-2 was less (P<0.01) than in canola meal, but the SID of Lys was not different among CE-1, CE-2, CE-3, and canola meal. Results from this experiment indicate that the SID of AA in CE is mostly comparable with that of canola meal, but the digestibility of CP and AA in the two camelina seeds was somewhat less than in CE and canola meal. Camelina expellers may, therefore, be included in diets fed to pigs.

Randall, K. M., Reaney, M. J. T. and Drew, M. D. 2013. Effect of dietary coriander oil and vegetable oil sources on fillet fatty acid composition of rainbow trout. Can. J. Anim. Sci. 93: 345-352. A 16-wk feeding trial was conducted to examine the effect of adding coriander oil to vegetable oil (VO) diets on the bioconversion of linoleic acid (LA; 18:2n-6) to arachidonic acid (ARA; 20:4n-6) and alpha-linolenic acid (ALA; 18:3n-3) to eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) in rainbow trout. The experimental treatments were a 4×2 factorial arrangement of diets using four dietary oils (fish, flax, canola and camelina oils) and two levels of coriander oil (0 and 5 g kg^-1 inclusion levels). Twenty-four tanks of triploid female rainbow trout (130 g initial weight; n=3) were used in the experiment. The experiment lasted 112 d during which fish were fed to satiation twice per day. The fatty acid composition of fillets from coriander-fed fish had increased concentrations of 20:5n-3 and 22:6n-3 (P<0.05). Furthermore, a trend to increased (20:5n-3 22:6n-3)/20:4n-6 ratios was seen when coriander oil was added to the diet (P=0.067). These results suggest that the addition of coriander oil to VO diets can significantly increase the bioconversion of 18:3n-3 to 20:5n-3 and 22:6n-3 in rainbow trout.

Zdunczyk, Z., Jankowski, J., Juskiewicz, J., Mikulski, D. and Slominski, B. A. 2013. Effect of different dietary levels of low-glucosinolate rapeseed (canola) meal and non-starch polysaccharide-degrading enzymes on growth performance and gut physiology of growing turkeys. Can. J. Anim. Sci. 93: 353-362. One-day-old male turkey poults were randomly assigned to eight dietary treatments and were fed diets containing 0, 60, 120, or 180 g kg^-1 of low-glucosinolate rapeseed meal (RSM) from 1 to 56 d of age without or with a commercial non-starch polysaccharide-degrading enzyme product containing pectinase, cellulase, xylanase, glucanase, mannanase and galactanase activities. There were no significant differences (P>0.05) in body weight and feed conversion ratio between the Control soybean meal-based diet and the diets containing RSM. Overall, the inclusion of up to 180 g kg^-1 of RSM did not affect the growth performance of turkeys. When compared with the Control treatment, the diet with the lowest RSM content increased the pH of the small intestinal contents and the amounts of cecal digesta. The moderate level of RSM also increased the pH of the small intestinal contents although no increase in the cecal digesta contents was noted. In comparison with other treatments, the highest RSM content increased the content of the small intestinal digesta considerably and decreased the pH of the small intestinal contents to that of the Control treatment. All three dietary levels of RSM significantly reduced the activity of bacterial β-glucuronidase in the ceca. Enzyme supplementation tended to reduce ileal viscosity (P=0.079), decreased ammonia concentration, increased the glycolytic activities of the intestinal microflora enzymes a-glucosidase, a-galactosidase, and β-galactosidase, decreased the activity of β-glucuronidase and increased the growth rate of turkeys.

Guadagnin, M., Tagliapietra, F., Cattani, M., Schiavon, S., Worgan, H. J., Belanche, A., Newbold, C. J. and Bailoni, L. 2013. Rumen fermentation and microbial yield of high- or low-protein diets containing ground soybean seeds or homemade rapeseed expellers evaluated with RUSITEC. Can. J. Anim. Sci. 93: 363-371. This experiment aimed to compare diets containing two crude protein (CP) concentrations [147 or 109 g kg^-1 in dry matter (DM)] and two protein sources containing ground soybean seed (GSS) or rapeseed expeller (RSE). Diets were compared in terms of digestibility, volatile fatty acids (VFA) and ammonia concentrations, and N flows, using rumen simulation fermenters (RUSITEC). Home-made RSE (CP=287 g kg^-1 dry matter and ether extract=199 g kg^-1 DM) was produced using equipment adopted by small farms. Reduction of dietary CP content did not affect digestibility, except for a reduction of N apparent digestibility (P<0.01), but increased efficiency of N utilization (P=0.001) without affecting microbial N production (P=0.82). Total VFA concentration was not (P=0.56) influenced by CP content. Compared with GSS, RSE exhibited a greater neutral detergent fibre digestibility (P<0.01), it did not influence total volatile fatty acids (VFA; P=0.10) but decreased the proportions of acetate and propionate on total VFA (P<0.001) and increased those of butyrate and branched-chain VFA (P<0.001). Microbial efficiency was comparable for GSS and RSE. Results suggest that reduction of dietary CP concentration in DM did not impair in vitro digestibility and microbial growth. The protein mixture containing homemade RSE showed in vitro fermentative properties and microbial growth comparable with those of GSS.

Hünerberg, M., McGinn, S. M., Beauchemin, K. A., Okine, E. K., Harstad, O. M. and McAllister, T. A. 2013. Effect of dried distillers' grains with solubles on enteric methane emissions and nitrogen excretion from finishing beef cattle. Can. J. Anim. Sci. 93: 373-385. The objective of this study was to examine the impact of corn- or wheat-based dried distillers'grains with solubles (CDDGS, WDDGS) on enteric methane (CH₄) emissions from finishing beef cattle, and to determine if any observed reductions were a result of the fat content of CDDGS. A second objective was to compare the effect of CDDGS or WDDGS on N excretion. The experiment was designed as replicated 4×4 Latin square with 28-d periods using 16 ruminally fistulated crossbred heifers. The control diet contained 87% barley grain, 8% barley silage and 5% supplement (dry matter; DM basis). Treatment diets were formulated by replacing 40% DM of barley grain with CDDGS, WDDGS, or corn oil supplemented WDDGS (WDDGS oil). For the WDDGS oil diet 6.5% corn oil was added to WDDGS (3.4% fat DM) to achieve a similar fat level as in CDDGS (9.7% DM). All diets were fed as total mixed rations once daily ad libitum. Total collection of urine and faeces was conducted between days 18 and 21. Methane was measured between days 25 and 28 using four identical open circuit respiratory chambers. Compared with WDDGS, feeding CDDGS and WDDGS oil reduced (P<0.05) CH₄ emissions as a percentage of gross energy intake (GEI) from 5.5 to 4.0 and 4.2%, respectively. Feeding CDDGS also reduced (P<0.05) CH₄ emissions compared with the control (5.0% of GEI), while WDDGS oil tended (P=0.08) to elicit a similar response. Methane (% of GEI) between WDDGS and the control did not differ (P=0.29). Excretion of total N was greater (P<0.001) for CDDGS, WDDGS and WDDGS oil (220, 253, and 265 g d^-1) compared with the control (143 g d^-1). Although oil appears to be responsible for reducing CH₄ emissions when DDGS is included in the diet, increased N excretion requires that a complete life cycle assessment be conducted to assess the full impact of DDGS on greenhouse gas emissions from finishing cattle.

Li, Y. L., Li, C., Beauchemin, K. A. and Yang, W. Z. 2013. Effects of a commercial blend of essential oils and monensin in a high-grain diet containing wheat distillers' grains on in vitro fermentation. Can. J. Anim. Sci. 93: 387-398. Our objective was to evaluate in vitro effects of a commercial blend of essential oils (BEO) versus monensin (MON) on fermentation of a high-grain diet containing wheat distillers' dried grains with solubles (DDGS). Two experiments were conducted. The first experiment was designed as a short-term batch culture to determine the optimum dose of BEO (0, 45, 90 or 180 mg kg^-1 DM) on fermentation variables. The second experiment was a completely randomized block design with a 2×2 factorial arrangement of treatments using the rumen simulation technique. A high-grain dietary substrate containing wheat DDGS was supplemented with 0 or 28 mg MON kg^-1 DM combined with 0 and 90 mg BEO kg^-1 DM. Monensin did not affect the total volatile fatty acid (VFA) concentration or the molar proportions of individual VFA, but reduced CH₄ production (mL L^-1 gas; P=0.01) and disappearance of DM (P=0.04). Supplementation of BEO did not affect VFA concentration, but decreased (P=0.01) the molar proportion of acetate and reduced (P=0.02) the acetate to propionate concentration ratio and CH₄ production (mL g^-1 digested organic matter). The BEO increased (P=0.01) disappearance of neutral detergent fiber without affecting disappearance of other nutrients. These results indicate that supplementation of high-grain dietary substrate containing wheat DDGS with BEO improved fermentation pattern by increasing propionate concentration, reducing CH₄ production, and increasing fiber digestibility. This commercial BEO could be a potential substitute for MON for beef cattle fed high-grain diets containing DDGS.

Plaizier, J. C. and Li, S. 2013. Short Communication: Prediction of in vitro dry matter digestibility with the ANKOM Daisy II system of ruminant feeds using the gas production technique. Can. J. Anim. Sci. 93: 399-402. The potential of the gas production technique to predict in vitro dry matter digestibility was determined using 50 ruminant feeds, including grass/alfalfa forages, grain crop silages, grains, high protein feeds, and feed straws. Without including the chemical composition in the prediction equation, the prediction of IVDMD based on the cumulative gas production during 48 h alone was poor (R²=0.48). Including the crude protein and neutral detergent fibre concentrations of the feed in the prediction equation improved the accuracy of the prediction (R²=0.87), which was higher than that of predicting IVDMD based on the chemical composition alone (R²=0.82).