Cook, N. J. 2012. Review: Minimally invasive sampling media and the measurement of corticosteroids as biomarkers of stress in animals. Can. J. Anim. Sci. 92: 227-259. The measurement of corticosteroid hormones is commonly used as a biomarker of an animal's response to stress. The difficulties in obtaining blood samples and the recognition of the stressor effect of blood sampling are primary drivers for the use of minimally invasive sample media. In mammals these include saliva, feces, urine, hair, and milk. In birds, samples include excreta, feathers, egg yolk and albumin. In fish, corticosteroids have been measured in excreta and swim-water. Each of these sample media incorporate corticosteroids in accordance with the processes by which they are formed, and this in turn dictates the periods of adrenocortical activity that each sample type represents. Cortisol in saliva represents a time-frame of minutes, whereas the production of feces may be hours to days depending on the species. The longest time-integrations are for hair and feathers which could be over a period of many weeks. The sample media also determines the structural changes that may occur via processes of conjugation to glucuronides and sulfides, metabolic conversion via enzymatic action, and bacterial breakdown. Structural changes determine the optimum methodologies used to measure corticosteroid hormones. In most sample media, measurement of a specific corticosteroid is a requirement depending on the species, e.g., cortisol in most mammals, or corticosterone in birds. However, in samples involving products of excretion, methodologies that measure a broad range of structurally related compounds are probably optimal. The utility of minimally invasive sample media as biomarkers of stress responses depends on the degree to which the corticosteroid content of the sample represents adrenocortical activity. Commonly, this involves comparisons between corticosteroid concentrations in blood plasma with concentrations in the alternative sample media. This review focuses on the methodological and biological validation of corticosteroid measurements in minimally invasive samples as biomarkers of adrenocortical responses to stress.

Yegani, M. and Korver, D. R. 2012. Review: Prediction of variation in energetic value of wheat for poultry. Can. J. Anim. Sci. 92: 261–273. Variations in physical and chemical characteristics of wheat can significantly influence the energy availability of this feed ingredient for poultry. These variations can result in inefficiencies in the form of over- or under-formulation of the diets at commercial feed mills or on poultry farms. Therefore, having a clear understanding of the variations is of paramount importance in the formulation of poultry diets as they can have negative consequences for production performance of birds. There are a large number of factors that can contribute to variations in energy availability of wheat for poultry. This review is intended to briefly discuss these factors and also practical approaches that can be used to predict these variations. These approaches include measuring physico-chemical characteristics, in vivo digestibility trials, in vitro digestibility techniques, and near infrared reflectance spectroscopy (NIRS). There are limitations associated with physico-chemical and in vivo measurements. However, in vitro digestibility techniques are simple and fast and can provide data for database development and ongoing calibrations of NIRS systems. Near infrared reflectance spectroscopy has enormous potential to predict variations in wheat apparent metabolizable energy, leading to more accurate diet formulation.

Palma-Irizarry, M., Damian-Matsumura, P., Betancourt, M., Romo, S., Perales, G., Lagunas-Martínez, A., Madrid-Marina, M. V., Mejía, O. and Ducolomb, Y. 2012. Identification of novel variants of interferon-tau gene in Bighorn sheep (Ovis canadensis mexicana), Pelibuey sheep (Ovis aries) and its expression in hybrid blastocysts (Ovis canadensis×Ovis aries). Can. J. Anim. Sci. 92: 275-283. The major signal for maternal recognition of pregnancy (MRP) in ruminants is interferon-tau (IFNT). Four novel sequences of the IFNT gene were isolated from genomic DNA obtained from blood samples of Bighorn, Pelibuey or the hybrid ewes. The deduced amino acid sequence of the hybrid ewe showed 100% identity with one Bighorn sheep IFNT sequence, suggesting that this sequence was inherited from Bighorn sheep. The high degree of identity between Pelibuey and Bighorn sheep sequences could be a possible explanation for the successful MRP in some Bighorn hybrid pregnancies. In vivo and in vitro domestic sheep (Ovis aries) and hybrid sheep (Ovis aries×Ovis canadensis) blastocysts were obtained, and IFNT expression was measured by semiquantitative RT-PCR. In vivo and in vitro hybrid blastocysts showed lower expression of IFNT when compared with domestic blastocysts. In conclusion this study showed that there exists an effect of hybridization on IFNT expression and this can affect the MRP.

Koeck, A., Miglior, F., Kelton, D. F. and Schenkel, F. S. 2012. Short Communication: Genetic association of body condition score with disease resistance in first lactation Canadian Holsteins. Can. J. Anim. Sci. 92: 285-289. The objective of this study was to investigate if body condition score (BCS) can be used as an indicator of specific diseases in first lactation Canadian Holstein cows. Body condition score was routinely recorded by professional type classifiers, as part of the national type classification system. Health data recorded by producers were available from the national dairy cattle health recording system. Body condition score was genetically negatively correlated with several health disorders, indicating that animals with a higher BCS have fewer disease cases. The results imply that BCS could be used to indirectly select for animals that are more resistant to specific diseases.

Huang, L., Jin, S-Y., Xu, Y-O., Li, Y-P., Lin, Y-Q. and Zheng, Y-C. 2012. Quantitation of alternative splicing variants of lactate dehydrogenase C gene in testes of adult yak, sexually immature yak calf and sterile male hybrid of yak. Can. J. Anim. Sci. 92: 291-296. The main objective of the present study was to analyze quantitatively the alternative splicing of the lactate dehydrogenase C (ldhc) gene in the testes of yak (Bos grunniens) and male sterile yak hybrid. RT-PCR amplification of ldhc cDNA in the testes revealed eight splice variants formed by the deletion of one or more exons in the mRNA transcripts. The deleted exons occur mostly in exons 7 and 4. The deletion of exons caused reading frame shift and formation of stop codon in some variants. Quantitative real-time RT-PCR analysis using ldhc variant-specific primers showed that the mRNA level of full length ldhc decreased dramatically in the testes of sexually immature yak calf (n=6) and male sterile hybrid cattle-yak (n=4) compared with that of adult yak (n=14). The proportions of the ldhc variants assayed differed significantly among adult yak, yak calf and cattle-yak; more ldhc transcripts were spliced in immature or sterile testes. Our results suggest that the alternative splicing could play a role in the regulation of ldhc expression in testes, and could be one factor that plays a role in infertility of yak hybrids.

Ilse, B. R., O'Neil, M. R., Lardy, G. P., Reynolds, L. P. and Vonnahme, K. A. 2012. Impacts of linseed meal and estradiol-17β on cellularity, angiogenic and vasoactive factor mRNA expression, and vascularity of the uterus in ovariectomized ewes. Can. J. Anim. Sci. 92: 297-306. The objective of the current study was to determine the estrogenic potential of the phytoestrogen secoisolariciresinol diglycoside (SDG) found in linseed meal (LSM) on uterine cell proliferation, vascularity, and angiogenic factor mRNA expression. Ovariectomized ewes (n=48) were fed a diet containing 12.5% LSM for 0, 1, 7, or 14 d and implanted with estradiol-17β (E2) for 0, 6, or 24 h before tissue collection. There was an interaction of LSM×E2 on uterine mass (grams; P=0.03; percentage change; P<0.003). Uterine mass increased (P≤0.02) after 24 h of E2 exposure on days 1, 7, and 14 of LSM feeding, with the greatest mass occurring in ewes exposed to E2 for 24 h and 1 d LSM feeding. Regardless of days fed LSM, after 24 h of E2 exposure uterine mass was greatest. The greatest percentage increase in uterine mass occurred in ewes exposed to E2 for 24 h and fed 1 d of LSM. Cell proliferation within the uterine luminal epithelium was greatest (P<0.01) with 24 h of E2 exposure compared with 0 h and 6 h. When expressed as the percentage change in uterine cell proliferation, feeding LSM for 14 d negated these effects. Only length of E2 exposure impacted vascularity with capillary number density at 6 h of E2 exposure being greater (P=0.02) than at 24 h. While mRNA expression of several angiogenic factors was influenced by E2, there was a LSM×E2 interaction (P≤0.03) only on vascular endothelial growth factor receptor 2 and fibroblast growth factor receptor 2C. It appears that growth and angiogenesis of E2 sensitive tissues may be influenced by the duration of LSM feeding.

Khonyoung, D., Yamauchi, K., Buwjoom, T., Maneewan, B. and Thongwittaya, N. 2012. Effects of dietary dried fermented ginger on growth performance, carcass quality, and intestinal histology of heat- stressed broilers. Can. J. Anim. Sci. 92: 307-317. To investigate the effects of a dried fermented ginger product (DFG) on growth performance, carcass quality, and intestinal histology of heat-stressed broiler, at 7 d of age, 200 male broilers were divided into 0% (control), 0.25% (0.25 S F), 0.5% (0.5 S F) and 1% (1 S F) dietary DFG groups fed from 7 to 49 d of age (starter finisher groups, S F). Another group of chicks was fed the basal diet until 21 d of age. At 22 d of age, 150 birds from this group showing almost similar body weight were divided into 0.25% (0.25 F), 0.5% (0.5 F) and 1% (1 F) dietary DFG groups fed from 22 to 49 d of age (finisher groups, F); the control group was common for the S F and F groups. The average temperature was around 31°C (23.2-38.6°C) throughout the trial. Compared with the control, the experimental DFG groups were not different in feed intake, body weight gain, feed efficiency and carcass quality. However, abdominal fat of the 1 S F, 0.5 F, and 1 F groups decreased (P<0.05). Cell mitosis numbers in the duodenum tended to increase in the 1 S F group (P<0.1). Epithelial cells on the jejunal villus apical surface of the control were mainly flat, and desquamations were observed. Desquamation was reduced with increasing DFG, and in the 1% DFG groups, many protuberant cells and cell clusters were present. The present results suggest that under high ambient temperature 1% dietary DFG from 7 to 49 d of age can decrease abdominal fat, and that jejunal villus apex was desquamated with heat stress, but desquamations were reduced with increasing DFG, and disappeared in 1% DFG groups.

Faucitano, L., Torrey, S., Matte, J. J., del Castillo, J. R. E. and Bergeron, R. 2012. Effects of water supplementation with tryptophan and vitamin B₆ or feeding hydrogenated fat on reducing hunger-induced drinking pre-slaughter in pigs. Can. J. Anim. Sci. 92: 319-326. A current food safety challenge at pig slaughter plants comes with the presence of stomachs filled with liquid induced by hunger-related drinking in lairage. With the objective to reduce hunger-related excess drinking, 30 barrows were assigned to three treatments (10 pigs per treatment): (1) unsupplemented water or feed regimen (CONT), (2) L-Tryptophan (3 g L^-1) and vitamin B₆ (10 mg L^-1) in the drinking water for 5d (TRP-B6), (3) hydrogenated fat (HF) supplemented at 10% in the diet for the last day of feeding before pre-slaughter fasting. As compared with CONT, neither TRP-B6 nor HF supplementation influenced behaviour in lairage and water intake at anytime over the pre-slaughter fasting period as reflected on stomach weight and its liquid content at slaughter (P>0.10). However, in HF-fed pigs plasma non-esterified fatty acids concentrations tended to be lower (P=0.09) while carcass yield was higher (P=0.04) than CONT pigs. It appears, therefore, that neither drinking water supplementation with TRP-B6 for 5 d nor feeding HF the last day before slaughter can be recommended strategies to limit excess water drinking prior to slaughter and liquid stomach content at slaughter. However, dietary HF supplementation the last day before slaughter may attenuate the effects of fasting on body energy reserves and improve carcass yield.

McGregor, E M., Campbell, C. P., Miller, S. P., Purslow, P. P. and Mandell, I. B. 2012. Effect of nutritional regimen including limit feeding and breed on growth performance, carcass characteristics and meat quality in beef cattle. Can. J. Anim. Sci. 92: 327-341. The effects of nutritional management regimen and breed on growth performance, carcass attributes, and meat quality were evaluated in 68 British (BRIT) and Continental (CONT) crossbred steers, managed on one of three nutritional regimens: (1) ad libitum access to a 77% corn diet (ALGRAIN), (2) limit feeding initially of the 77% corn diet, followed by ad libitum access to the 77% corn diet (LFGRAIN), and (3) limit feeding initially of a 90% haylage diet, followed by ad libitum access to the 77% corn diet (LFHAYL). Nutritional regimen by breed interactions (P<0.02) were present for average daily gain, dry matter intake (DMI), gain to feed, and shear force. LFHAYL regimen decreased gains to a greater extent for BRIT steers than CONT steers managed on ALGRAIN or LFGRAIN. Feed intakes were similar across nutritional regimens for CONT steers, while DMI was depressed in BRIT on LFHAYL as compared with steers started on ALGRAIN or LFGRAIN. Gain to feed was greater in BRIT cattle on LFGRAIN vs. ALGRAIN, while gain to feed was similar in CONT started on grain (ALGRAIN, LFGRAIN). Shear force was lower for beef from LFHAYL BRIT vs. beef from BRIT on ALGRAIN or LFGRAIN, while the converse was true for CONT. Limit feeding of a high-energy diet may be appropriate for cattle of British background to reduce feed input costs, while ensuring tenderness.

Amat, S., Hendrick, S., McAllister, T. A., Block, H. C. and McKinnon, J. J. 2012. Effects of distillers' dried grains with solubles from corn, wheat or a 50:50 corn:wheat blend on performance, carcass characteristics and serum sulphate levels of feedlot steers. Can. J. Anim. Sci. 92: 343-351. Two trials were conducted to evaluate the effects of corn (CDDGS), wheat (WDDGS) or a 50:50 corn:wheat blend (BDDGS) dried distillers' grains with solubles (DDGS) on performance (Trials 1 and 2), carcass traits (Trial 2) and serum sulphate level (Trial 2) of steers. In Trial 1, 396 steers (281.1±19.6 kg) were fed one of three backgrounding diets. The control diet was 34.3% barley grain, 26.0% grass hay, 10.3% barley straw, 22.8% barley silage and 6.7% supplement [dry matter (DM) basis]. For the two treatments, 17% of the barley was replaced with CDDGS or WDDGS. In Trial 2, 288 steers (273.9±18.5 kg) were backgrounded and finished. Backgrounding diets were identical to Trial 1, with a third treatment where 17% of the barley grain was replaced with BDDGS. The control finishing diet was 86.8% barley grain, 7.4% barley silage and 5.8% supplement (DM basis). Treatments included replacement of 40% of the barley grain (DM basis) with CDDGS, BDDGS or WDDGS. In Trial 1, there was no effect of DDGS on dry matter intake (DMI) (P=0.49), average daily gain (ADG) (P=0.64), feed efficiency (P=0.06), ultrasound fat (USFAT) (P=0.90) or longissimus dorsi (USLD) (P=0.071) area. In Trial 2, overall, DMI of cattle fed WDDGS was higher (P=0.03) than control or CDDGS cattle, with BDDGS intermediate. In contrast, ADG was higher (P<0.01) for the CDDGS and BDDGS than either the control or WDDGS fed cattle. The CDDGS and BDDGS cattle were more efficient (P<0.01) than those fed WDDGS with the controls intermediate. Cattle fed CDDGS or WDDGS exhibited higher (P<0.01) serum sulphate levels compared with BDDGS or control cattle, reflecting differences in sulphur intake. The results indicate that CDDGS is a superior energy source to WDDGS and that both sources of DDGS can be used as a partial replacement for barley in backgrounding and finishing diets for cattle.

Li, S., Gozho, G. N., Gakhar, N., Khafipour, E., Krause, D. O. and Plaizier, J. C. 2012. Evaluation of diagnostic measures for subacute ruminal acidosis in dairy cows. Can J. Anim. Sci. 92: 353-364. Effects of subacute ruminal acidosis (SARA) challenges on measurements of feces, urine, milk and blood samples, and of feeding behavior were investigated to determine which of these measurements may aid in the diagnosis of SARA. Eight multiparous lactating dairy cows were used in a crossover design with two 6-wk experimental periods. During weeks 1, 2, and 6, cows received a control diet with a forage-to-concentrate ratio of 58:42. During weeks 3 to wk 5, a grain-based SARA challenge (GBSC) or an alfalfa-pellet SARA challenge (APSC) was conducted by replacing 12% of the dry matter of the control ration with pellets containing 50% ground wheat and 50% ground barley, and by replacing 26% of the dry matter of the control ration with pellets of ground alfalfa, respectively. The rumen pH depression did not differ between the challenges. The GBSC increased the concentrations of lipopolysaccharide (LPS) in feces and of serum amyloid A in blood, but decreased that of milk fat and urea in blood. The APSC increased the urine pH, the net-acid-base excretion, and the red blood cell count and potassium concentration in blood. Both challenges increased the concentrations of LPS and propionate in rumen fluid, protein in milk, glucose, lactate and sodium and the partial pressure of CO₂ in blood, and tended to decrease the concentration of chloride in blood. The measures that were similarly affected by both challenges may aid in the diagnosis of a rumen pH depression. Differences between the SARA challenges suggest that this disorder is not solely rumen pH dependent.

Ramirez, H. A. R., Nestor, K., Tedeschi, L. O., Callaway, T. R., Dowd, S. E., Fernando, S. C. and Kononoff, P. J. 2012. The effect of brown midrib corn silage and dried distillers' grains with solubles on milk production, nitrogen utilization and microbial community structure in dairy cows. Can. J. Anim. Sci. 92: 365-380. Thirty-six Holstein cows (24 multiparous and 12 primiparous), four multiparous were ruminally cannulated, (mean±SD, 111±35 days in milk; 664±76.5 kg body weight) were used in replicated 4×4 Latin squares with a 2×2 factorial arrangement of treatments to investigate the effects of brown midrib (bm3) and conventional (DP) corn silages, and the inclusion of dried distillers' grains with solubles (DDGS) on milk production and N utilization. Experimental periods were 28 d in length. Treatments were DP corn silage and 0% DDGS; bm3 corn silage and 0% DDGS; DP corn silage and 30% DDGS; and bm3 corn silage and 30% DDGS. Compared with DP hybrid, total tract fiber digestibility was greater for cows consuming bm3 (32.5 vs. 38.1±1.79%) and DDGS (40.0 vs. 35.2±1.76%). Milk yield was not affected by treatment, and averaged 30.5±1.09 kg d^-1. Milk protein yield was positively affected by bm3 corn silage and the inclusion of DDGS. An interaction between hybrid and DDGS on milk fat was also observed. The nature of the interaction was such that milk fat was only affected when DDGS were included in the diet and the lowest milk fat was observed when bm3 corn silage was fed (3.46, 3.59, 2.84 and 2.51±0.10% DP 0% DDGS, bm3 0% DDGS, DP 30% DDGS and bm3 30% DDGS, respectively). As a proportion of the total N consumed, manure N was significantly reduced by the inclusion of bm3 corn silage and DDGS (64.1, 57.1, 52.0, 51.2% for DP 0% DDGS, bm3 0% DDGS, DP 30% DDGS and bm3 30% DDGS, respectively). The Firmicutes:Bacteriodetes ratio in the rumen decreased when cattle consumed DDGS. When cows were fed bm3 corn silage, the population of Fibrobacter sp. tended to represent a larger proportion of the total bacterial population (1.8 vs. 2.3±0.28% for DP and bm3, respectively) and this shift may have been driven by the fact that bm3 corn silage has less lignin, therefore the cellulose digesting bacteria may have more access to the cellulose.

Addah, W., Baah, J., Okine, E. K. and McAllister, T. A. 2012. Use of thermal imaging and the in situ technique to assess the impact of an inoculant with feruloyl esterase activity on the aerobic stability and digestibility of barley silage. Can. J. Anim. Sci. 92: 381-394. Feruloyl esters limit the digestibility of forages, a constraint that may be overcome if additives with feruloyl esterase (FE) activity are applied to forage. This study determined if a FE-producing strain of Lactobacillus buchneri LN4017 in combination with Lactobacillus plantarum LP7109 and Lactobacillus casei LC3200 improves fermentation, aerobic stability and in situ fibre disappearance of whole-crop barley silage. Barley forage (350 g kg^-1 DM) was either uninoculated (UN) or inoculated (1.3×10⁵ CFU g^-1 fresh forage; IN) and ensiled in Ag-Bag^® silos. Bags were opened after 90 d of ensiling. Samples were collected on day 95, 123 and 175 for determination of fermentation characteristics. Surface temperature of the face of each bag was measured over 3 d using a thermal infrared camera. Ruminal in situ DM and NDF disappearance (aNDFD) of silage and rumen fermentation patterns were measured using three ruminally cannulated heifers. The L. buchneri-treated silage possessed a higher acetic acid concentration than UN (48.8 vs.18.4 g kg^-1 DM). The temperature at the face of IN was lower than UN immediately upon exposure and after 3 d of aerobic exposure. Inoculation increased (P=0.01) 24-h and 48-h aNDFD with a trend towards a glucogenic pattern of ruminal fermentation in heifer compared with UN silage. There was evidence that the FE-producing inoculant improved aerobic stability and aNDFD of whole-crop barley silage.

Tekippe, J. A., Hristov, A. N., Heyler, K. S., Zheljazkov, V. D., Ferreira, J. F. S., Cantrell, C. L. and Varga, G. A. 2012. Effects of plants and essential oils on ruminal in vitro batch culture methane production and fermentation. Can. J. Anim. Sci. 92: 395-408. In this study, plants (14) and essential oils (EO; 88) from plants that are naturalized to, or can be successfully grown in North America were evaluated in a batch culture in vitro screening experiments with ruminal fluid as potential anti-methanogenic additives for ruminant diets. Essential oils were tested at four inclusion levels: 0 (blank), 10, 50, and 100 mg L^-1 and plants were tested at 313, 1250, 2500, and 5000 mg L^-1 final incubation medium concentration. Compared with the blank, two of the EO increased acetate concentration (8 to 10%), 11 EO increased propionate concentration (9 to 23%), 10 EO increased butyrate concentration (24 to 29%), and three EO reduced methane production [20 to 30%; Anethum graveolens (dill weed oil), Lavandula latifolia, and Ocimum basilicum #7 accession]. Four EO decreased and one increased neutral detergent fiber (NDF) degradability. Three plants increased acetate concentration (8 to 12%), two increased propionate concentration (16%), and one (Origanum vulgare) decreased methane production (31%). Eight of the plants increased NDF degradability at various inclusion levels. Overall, these results indicate that some EO, or EO-producing plants could have a potential anti-methanogenic effect. Further research is needed to verify these results in vivo in long-term experiments.