Durunna, O. N., Baron, V., Scott, S. L., Robins, C., Khakbazan, M. and Block, H. C. 2015. Effects of resting perennial pastures during the sensitive pre-dormancy period in western Manitoba: Pasture productivity and beef cattle performance. Can. J. Anim. Sci. 95: 129-141. The objective of this experiment was to determine whether avoiding grazing during the sensitive pre-dormancy period (ca. 6 wk prior to a dormancy-inducing frost) would improve forage production, stand quality, alfalfa persistence and animal productivity in perennial pastures. There were two pasture species (PS), alfalfa-grass (AG) or grass (G), and three grazing phases. Phase I was conventional rotational grazing of all AG and G sections. In Phase II, one half of AG and G was rotationally grazed (conventional treatment, CT) while the other half was not (rested treatment, RT). Resting AG and G in Phase II required transferring RT animals to swath-graze early-seeded cereals. In Phase III, RT animals that swath-grazed in Phase II were moved to graze the rested sections of the pastures while those that grazed the unrested sections (CT animals) were transferred to swath-graze late-seeded cereals. There was no PS (P>0.05) or rest period (P>0.13) effect on total forage yield, carrying capacity, forage disappearance and forage residues. There was no effect (P>0.13) of resting on botanical composition or yield in AG. The current study did not observe significant benefits of resting on pasture yield, botanical composition or animal performance.

Dominguez P.A., Pro-Martinez, A., Narciso-Gaytán, C., Hernández-Cázares, A., Sosa-Montes, E., Perez-Hernandez, P., Caldwell, D. and Ruiz-Feria, C. A. 2015. Concurrent supplementation of arginine and antioxidant vitamins E and C reduces oxidative stress in broiler chickens after a challenge with Eimeria spp. Can. J. Anim. Sci. 95: 143-153. Oxidation is a major problem associated with pathogen damage in animals. One-day-old mixed-sex broiler chicks (Cobb 500; n=624) were randomly assigned to one of six treatments: a basal diet [CTL; 40 mg of vitamin E (VE) kg^-1 of feed and 1.5% Arginine (Arg)] or the basal diet plus Arg (ARG; 0.3%), Arg VE (AVE; 0.3% and 40 mg kg^-1 respectively), Arg vitamin C (VC) (AVC; 0.3% and 1 g kg^-1 respectively), VE VC (VEC; 40 mg 1 g kg^-1 respectively), or Arg VE VC (AVEC; 0.3% 40 mg 1 g kg^-1 respectively). At day 14, all birds were orally challenged with 100× the normal dose of Advent^® coccidiosis vaccine (450 000 oocysts). Intestinal lesion scores (LS) in duodenum, jejunum and ceca were recorded, along with relative immune system organ weights at day 23. Plasma samples were taken before (2 h) and after challenge (12, 24 and 48 h) to determine malondialdehyde (MDA), nitric oxide (NO) and glutathione peroxidase activity (GPx). Birds fed the VEC diet were heavier at 7 d (P<0.05) than birds fed the AVE diet. CTL birds had heavier (P<0.05) bursas than AVC birds; no differences among treatments for spleen and thymus were found. The jejunum LS was lower in the AVC and VEC birds than in CTL birds, whereas ceca LS was highest in AVE birds, and the duodenum LS was not affected by treatment. Birds fed the AVEC diet had the lowest MDA levels before challenge, but higher levels of MDA than birds fed the CTL, ARG or AVE 12 h after challenge. Before challenge ARG birds had higher (P<0.05) NO levels than AVEC-fed birds, but 12 h after challenge birds fed the CTL, ARG or AVE diet had lower NO levels than birds fed the AVC, VEC or AVEC diet. Before challenge AVEC-fed birds had higher (P<0.001) GPx activity than CTL, ARG and AVE birds, but after 12, 24 and 48 h VEC birds showed higher GPx activity than CTL, ARG- and AVE-fed birds. Although Arg, VE and VC, modulated oxidative stress during coccidiosis challenge, the effects were not sufficient to affect performance relative to the control diet.

MacNeil, M. D. and Kemp, R. A. 2015. Genetic parameter estimation and evaluation of Duroc boars for feed efficiency and component traits. Can. J. Anim. Sci. 95: 155-159. The objective of this research was to produce a genetic evaluation for traits related to feed efficiency of Duroc boars. Meeting this objective required partitioning phenotypic (co)variance into additive genetic and environmental components for feed intake and traits indicative of growth and body composition. Boars (N=3291) were housed in group pens of 22 to 24 animals with two electronic feeders per pen and feed intake was recorded for 8 to 14 wk. Body weight was recorded for each boar at the start and end of test, at approximately 100 kg and at up to three times during the test. The pedigree used contained sire and dam of each boar with at least one recorded phenotype (N=4651) and their maternal and paternal grandsires. Variance components were estimated by restricted maximum likelihood for animal models in a series of uni-variate and bi-variate analyses. Two multiple trait genetic evaluations were conducted to predict estimated breeding value for feed intake using animal models. The first evaluation included feed intake (h²=0.33±0.05), age at 100 kg (h²=0.31±0.04), and subcutaneous fat depth (h²=0.47±0.05). The second genetic evaluation included feed intake, average daily gain (h²=0.27±0.04), mid-test weight (h²=0.33±0.05), and subcutaneous fat depth. Genetic correlations of feed intake with age at 100 kg and fat depth were -0.80±0.05 and 0.57±0.08, respectively. Estimated breeding values for measures of feed efficiency (residual feed intake and residual gain) were calculated from the results of the second analysis and the associated additive genetic (co)variance components.

Kułaj, D., Pokorska, J., Ormian, M. and Dusza, M. 2015. Short Communication: New alleles at the BoLA-DQA1 locus in Holstein Fresian cattle. Can. J. Anim. Sci. 95: 161-164. The aim of the study was to analyze genetic polymorphism at locus BoLA-DQA1 in Polish Holstein-Friesian cattle, using next generation sequencing technology (Miseq sequencer - Illumina). In the studied cattle population we identified 14 alleles, of which three were determined for the first time (BoLA-DQA1*0106, BoLA-DQA1*3201, BoLA-DQA1*3301). The frequencies of these alleles were respectively: 0.0423, 0.0282, 0.0282. At locus BoLA-DQA1 the highest frequency was found for the BoLA-DQA1*10011 and BoLA-DQA1*0101 alleles and their frequencies were respectively: 0.3592 and 0.2606. The frequencies of other alleles identified in the studied population ranged from 0.0070 to 0.0704. The results obtained in this study indicate that the BoLA-DQA1 locus is highly polymorphic and new alleles are still identifiable.

Li, Y. H., Li, F., Liu, M., Yin, J. J., Cheng, B. J., Shi, B. M. and Shan, A. S. 2015. Effect of γ-aminobutyric acid on growth performance, behavior and plasma hormones in weaned pigs. Can. J. Anim. Sci. 95: 165-171. The study was conducted the effects of dietary γ-aminobutyric acid (GABA, 0 and 30 mg kg^-1) on average daily intake, growth performance, behavior and plasma hormone levels in weaned pigs. A total of 96 28-d-old healthy weaned male pigs (Duroc×Landrace×Yorkshire) with similar weight were randomly assigned into two groups. Six units were included in each treatment, with eight pigs in each unit. The trial lasted 35 d. Four pigs were exchanged between every two pens in the same treatment on day 28. No difference was observed on average daily feed intake, average daily gain and feed-to-gain ratio between the pigs fed 30 mg kg^-1 GABA diets and the pigs fed basal diet, respectively. Longer feed consumption time and lower biting incidences were observed in pigs fed GABA, compared with those fed basal diet, respectively. Plasma growth hormone concentration was significantly increased and the plasma concentrations of adrenocorticotrophic hormone and cortisol were lower in weaned pigs in the GABA supplementation group on day 35. Dietary GABA significantly increased the plasma neuropeptide Y concentration on day 14 and day 35. It is indicated that dietary GABA reduced aggressive behavior and regulated endocrine hormones in weaned pigs, ultimately reducing the negative influences of stress (weaning and mixing) on the pigs.

Berthiaume, R., Lafrenière, C., Girard, C., Campbell, C. P., Pivotto, L. M. and Mandell, I. B. 2015. Effects of forage silage species on yearling growth performance, carcass and meat quality, and nutrient composition in a forage based beef production system. Can. J. Anim. Sci. 95: 173-187. Forty weaned, crossbred beef calves (predominantly Angus and Simmental) were forage-finished using all-silage diets (red clover-timothy versus tall fescue) to examine forage species' effects on growth performance, carcass traits, meat quality, and nutrient composition. Weaned calves (257 d of age) were forage-finished using red clover-timothy or tall fescue silage and harvested at approximately 1 yr of age. During carcass processing, one side from each carcass was covered with a polyliner to examine if reducing rates of chilling could compensate for limited fat cover expected from low dietary energy contents fed, and limited time on feed. Longissimus thoracis, semimembranosus, and semitendinosus steaks were aged 10, 14, and 21 d to examine effects on Warner-Bratzler shear force values while fatty acid and vitamin B₁₂ composition were determined on 10-d-aged steaks. Average daily gain, feed efficiency, hot carcass weights, and longissimus muscle area were greater (P<0.03) when cattle were fed red clover-timothy versus tall fescue silage, most likely due to the higher protein content of red clover-timothy silage. Shear force was greater (P<0.002) in steaks from all muscles evaluated from cattle fed tall fescue versus red clover-timothy silage. In comparison to 10-d-aged steaks, 14 d of ageing were needed to reduce (P<0.001) shear force for longissimus steaks, while 21 d of ageing were needed to reduce (P<0.001) shear force for semitendinosus steaks. Use of a polyliner decreased (P=0.0001) the rate of temperature decline at selected carcass sites, but did not reduce shear force values. The percent of n-3 fatty acids and polyunsaturated fatty acid/saturated fatty acid ratio were greater (P<0.04) in longissimus from cattle fed red clover-timothy versus feeding tall fescue silage. Feeding red clover-timothy silage improved growth performance, carcass, shear force, and fatty acid composition traits versus feeding tall fescue silage.

Chen, C., Han, L., Yu, Q.-L. and Li, R.-R. 2015. Color stability and antioxidant capacity of yak meat as affected by feeding with pasture or grain. Can. J. Anim. Sci. 95: 189-195. The objective of the present study was to analyze the effect of pasture or grain on color stability and antioxidant capacity of M. longissimus lumborum (LL) from pasture-fed (PF) or grain-fed (GF) yaks. The color stability and metmyoglobin percentage (MetMb%) were determined during 9 d of aerobic refrigerated storage. The antioxidant capacity was estimated by the total phenolics content, Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP). Compared with the GF group, the LL from the PF group showed significantly (P<0.05) higher redness (a* values), with lower decline rate in a* values (P<0.05) over 1 to 7 d of refrigerated storage. The LL from the PF group had a significantly (P<0.05) lower metmyoglobin accumulation rate. At the end of storage, the muscle's MetMb% of the PF and GF group were 46.33 and 56.66%, respectively. The PF group showed significantly higher total phenolics content ( 23.94%; P<0.05) in muscles, resulting in greater TEAC and FRAP, which were 24.81 and 3.99% higher than the GF group (P<0.05), respectively. In conclusion, the pasture enhanced antioxidant capacity of yak meat and contributed to improve the meat color stability.

Thanh, B. V. L., Lessard, M., Chorfi, Y. and Guay, F. 2015. The efficacy of anti-mycotoxin feed additives in preventing the adverse effects of wheat naturally contaminated with Fusarium mycotoxins on performance, intestinal barrier function and nutrient digestibility and retention in weanling pigs. Can. J. Anim. Sci. 95: 197-209. This study was designed to determine the effect of feeding deoxynivalenol (DON) contaminated wheat to growing pigs on growth performance, digestibility and retention of nitrogen (N), phosphorus (P) and calcium (Ca). Secondly, we wished to evaluate the potential of four commercial anti-mycotoxin additives in preventing the adverse effects of DON. Sixty piglets (6.0 kg body weight) were assigned to six different corn-soybean meal-wheat diets (control diet: <0.5 mg kg^-1 DON; contaminated diet (DON-contaminated): 4 mg kg^-1; and four contaminated diets supplemented with a different anti-mycotoxin additive: DON GLUC (glucomannan), DON YBP (yeast, live bacteria, enzymes, plant extracts), DON ALU (aluminosilicate) and DON PC (preservation components). Piglets were housed individually in pens for 7 d and then transferred to metabolic crates for urine and feces collection for 7 d. At the end of these 2 wk, mannitol and lactulose doses were given by oral administration. Urine was collected for 24 h for an evaluation of barrier integrity of intestinal mucosa. The piglets were then euthanatized and intestinal samples collected for morphology studies. Feeding DON-contaminated wheat reduced average daily feed intake, average daily gain and G:F ratio compared with the control diet (P<0.05). Only DON PC diet restored the growth performance of piglets fed DON-contaminated diet. Daily retention of N and P was not affected by DON contamination or anti-mycotoxin additives, but retention of Ca was higher in piglets fed the DON-contaminated diets than the control diet. DON-contaminated diet reduced digestibility of dry matter, gross energy and fat, villi height in jejunum, and recovery of mannitol and lactulose compared with the control diet (P<0.05). Finally, DON concentrations in serum from piglets fed the DON-contaminated diets were higher than in the control diet (P<0.05). Piglets fed DON-contaminated wheat had reduced growth possibly caused by impaired jejunal morphology and decreased digestibility of energy and fat.

Krogh, U., Bruun, T. S., Amdi, C., Flummer, C., Poulsen, J. and Theil, P. K. 2015. Colostrum production in sows fed different sources of fiber and fat during late gestation. Can. J. Anim. Sci. 95: 211–223. The objective was to study yield and composition of colostrum and transient milk from 36 second-parity sows fed a standard lactation diet (CON) low in fiber or one of two high-fiber diets based on sugar beet pulp (SBP) or alfalfa meal (ALF), combined with one of three fat sources, palm fatty acid distillate (PFAD), soybean oil (SOYO) or trioctanoate (C8TG) from day 105 of gestation onward. Sows were milked at 0, 12, 24 and 36 h relative to onset of parturition. Jugular vein blood was collected on day 112 of gestation. Plasma acetate content was affected by dietary fiber and fat treatment (P<0.05), indicating altered intermediary metabolism. Colostrum yield, predicted from piglet birth weight, suckling duration and weight gain, was unaffected by dietary treatments (P>0.10). Colostral (24 h) and transient milk dry matter contents were greater in SOYO compared with PFAD and C8TG sows (P<0.05). Colostrum (12 and 24 h) and transient milk lactose contents were greatest in CON-fed sows compared with sows fed ALF or SBP diets (P<0.05). In conclusion, nutrition in late gestation affected the intermediary metabolism and colostrum composition, but did not affect colostrum yield of sows.

Smit, M. N., Zamora, V., Young, M. G., Campbell, N., Uttaro, B. and Beltranena, E. 2015. Empiric narrowing of the net energy value of reduced-oil corn distillers' dried grain with solubles for growing-finishing pigs. Can. J. Anim. Sci. 95: 225-241. This study attempted to empirically narrow down the net energy (NE) value of reduced-oil corn distillers' dried grains and solubles (RO-cDDGS) by evaluating the response in pig growth performance, live backfat and loin depth, carcass traits, and primal pork cuts tissue composition to feeding diets formulated increasing the assumed NE value of RO-cDDGS, expecting a brisk change in slope of the response at the point at which the NE value of RO-cDDGS would be identified. In total, 1056 cross-bred pigs (31.7 kg) housed in 48 pens by gender were fed dietary regimens including 30% RO-cDDGS (6.7% ether extract) with assumed NE values of 1.7, 1.85, 2.0, 2.15, 2.3, or 2.45 Mcal kg^-1 over five growth periods (Grower 1: days 0-21, Grower 2: days 22-42, Grower 3: days 43-63, Finisher 1: days 64-76, Finisher 2: day 77 to market weight). Pig body weights were measured and feed disappearance (ADFI) was calculated by pen on days 0, 21, 42, 63, 76 and weekly thereafter until target slaughter weight (120 kg). For the entire trial (days 0-76), increasing the assumed NE value of RO-cDDGS linearly increased (P<0.01) ADFI and total lysine intake, did not affect NE intake and daily weight gain (ADG), quadratically decreased (P<0.05) feed efficiency, linearly decreased (P<0.05) live backfat depth and backfat:loin depth ratio, and did not affect carcass characteristics or pork primal cut tissue composition. Segmented regression only identified a change in slope for carcass ADG and lean ADG at 1.85 Mcal kg^-1. These results indicate that the experimental approach taken was not reliable in narrowing down the NE value of RO-cDDGS because the decrease in dietary NE was too small (0.03 Mcal kg^-1 d), which limited the change in dietary Lys:NE ratio with increasing assumed NE value of RO-cDDGS. The approach resulted in progressive, but small changes in slope rather than a clearly identifiable point where one could conclude that the incremental dietary energy contribution from RO-cDDGS changed the response in a given variable.

Zenobi, M. G., Lardner, H. A., Jefferson, P. G. and McKinnon, J. J. 2015. Effect of feeding strategically blended feed pellets on rumen fermentation and nutrient digestion. Can. J. Anim. Sci. 95: 243-254. Five rumen-cannulated heifers (631±31 kg) were used in a 5×5 Latin square design to evaluate the effect of feeding blended by-product feed pellets (BP) on rumen fermentation and nutrient utilization. Four BP were formulated to be high in starch (HS) or fat (HF) and either low (LSP) or high (HSP) in soluble crude protein. The control diet consisted of 49.1% forage and 50.9% barley-based concentrate. Treatments were 50.3% forage and 49.7% BP (DM). Heifers fed HF BP had higher (P=0.05) mean pH values than those fed the control diet and tended (P=0.07) to have higher mean pH than those fed the HS BP. Feeding HF BP decreased (P<0.05) rumen propionate concentration without affecting acetate or total volatile fatty acid concentration. Rumen ammonia-nitrogen (N) levels and digestibility of crude protein was highest (P<0.05) for HS, intermediate for HF, and the lowest for the control. Feeding HF BP reduced (P<0.05) gross energy digestibility and digestible energy content relative to both the control and HS diets while both BP increased (P<0.01) their extract digestibility compared with the control. There was minimal effect of pellet soluble crude protein content. Total N excretion (% of N intake) was not affected (P>0.05) by treatment. These results indicate that BP had no adverse effects on rumen fermentation or apparent nutrient digestibility and did not result in issues with excess nutrient excretion. As such BP can be used as an alternative energy source in backgrounding diets to cereal grains and can help counteract volatility in feed grain prices.

Añez-Osuna, F., Penner, G. B., Larson, K., Jefferson, P. G., Lardner, H. A. and McKinnon, J. J. 2015. Effect of rumen degradable energy supplementation on forage utilization and performance of steers grazing stockpiled cool season perennial grass pastures. Can. J. Anim. Sci. 95: 255-265. The objective of this study was to evaluate the effects of supplementing rumen degradable energy using blended by-product pellets that differed in starch and degradable fiber content on forage utilization and performance of steers grazing stockpiled cool-season perennial grass (CSPG) pastures. Forty-five yearling crossbred steers (334±23.5 kg) stratified by body weight (BW) were randomly assigned to one of nine pastures (five steers/pasture) of mature cool-season perennial grasses. Each pasture was randomly assigned (n=3) to one of three treatments: no supplement (CON); low-starch/high degradable-fibre (LSHF; 40.3% starch; 29.5% NDF) pellet and high-starch/low-degradable fibre (HSLF; 48.6% starch; 22.8% NDF) pellet, both fed daily at 0.6% of BW (DM basis). The grazing period lasted 70 d (from early-August to mid-October). Over the 70-d study, forage CP decreased from 9.9±0.82 to 6.9±0.59% of DM and digestible energy content decreased from 2.6±0.04 to 2.2±0.04 Mcal kg^-1 of DM. Treatment did not affect forage utilization (P=0.50; 73.4±3.15%) or forage DM intake (P=0.90; 9.0±1.54 kg d^-1). Final BW and average daily gain (ADG) were not different (P>0.05) between LSHF (435±6.4 kg and 1.4±0.10 kg d^-1) and HSLF (439±10.4 kg and 1.5±0.14 kg d^-1) treatments. However, supplemented steers had higher (P<0.05) final BW and ADG than the control steers (402±5.6 kg and 1.0±0.09 kg d^-1). These results show that unsupplemented beef steers grazing stockpiled CSPG pastures were limited in both energy and protein intake and that supplementation with by-product feed pellets formulated to supply protein and energy either as starch or degradable fibre equally improved animal performance.

Acharya I. P., Schingoethe D. J., Kalscheur K. F. and Casper D. P. 2015. Response of lactating dairy cows to dietary protein from canola meal or distillers' grains on dry matter intake, milk production, milk composition, and amino acid status. Can. J. Anim. Sci. 95: 267-279. A study was conducted to determine the response of feeding two different crude protein (CP) concentrations [low protein (LP, 14.3% CP) and high protein (HP, 16.3% CP)] and sources of protein [canola meal (CM) and high-protein dried distillers' grains (HPDDG)] on dry matter intake, milk production and composition, and amino acid (AA) status of high producing dairy cows. Sixteen Holstein cows were used in a replicated 4×4 Latin square having a 2×2 factorial arrangement of treatments. All diets contained 55% forage (50% alfalfa hay and 50% corn silage) and 45% concentrate. Diets were formulated to contain LP with CM, LP with HPDDG, HP with CM and HP with HPDDG. Experimental feeding periods were 4 wk with data collected during weeks 3 and 4 of each period. Dry matter intake (24.6 vs. 25.9 kg d^-1 for LP and HP, respectively) was increased for cows fed the higher CP diets, milk yield was greater for cows fed HP diets (34.0 vs. 36.4 kg d^-1), and milk fat percentage was greater for cows fed HP compared with LP, but were similar between dietary protein sources. Feed efficiency calculated as fat-corrected milk and energy-corrected milk was greater for cows fed HP than LP, but was similar between sources. Dietary metabolizable protein of CM diets was utilized more efficiently than from HPDDG diets for milk protein production. Mammary gland extraction efficiency of essential AA indicated that Met was the first limiting AA for CM-based diets while Lys was first limiting for HPDDG-based diets. In summary, canola meal and distillers' grains are both good quality protein supplements for lactating cows.

Mercier, J., Cinq-Mars, D., Berthiaume, R., Faucitano, L. and Girard, C. L. 2015. Effects of dietary total non-structural carbohydrates and folic acid and vitamin B₁₂ supplement on growth and meat quality of yearling steers in a forage-based beef production system. Can. J. Anim. Sci. 95: 281-291. Thirty-two spring calving cows [760±91 kg body weight (BW)] and calves (44±4.5 kg BW) were assigned to eight blocks of four cows and their calves each according to parity and calving date. Within each block, two cows were fed a low total non-structural carbohydrate (TNC) diet, while the two others were fed a high TNC diet. Within each diet, cows were administered either no vitamins or weekly intramuscular injections of 160 mg of folic acid plus 10 mg of vitamin B₁₂. Calves were slaughtered at 305±9 d. Neither TNC concentration nor vitamin supplementation affected (P>0.10) milk yield but the vitamin supplementation increased (P=0.002) milk concentrations of vitamin B₁₂. There was no treatment effect on calf performance, or carcass and meat characteristics (P>0.10) except for collagen concentrations and shear force measurements in the longissimus lumborum muscle, which had a tendency to be decreased (P≤0.06) by the vitamin supplement. In the present study, differences in forage TNC concentrations did not influence cow and calf performance. Moreover, folic acid and vitamin B₁₂ supplements were shown to have little impact in this study on growth of beef cattle.

Cabral, R. G., Chapman, C. E., Kent, E. J. and Erickson, P. S. 2015. Estimating plasma volume in neonatal Holstein calves fed one or two feedings of a lacteal-based colostrum replacer using Evans blue dye and hematocrit values at various time points. Can. J. Anim. Sci. 95: 293-298. Twenty-eight Holstein calves were blocked by birth date and randomly assigned to one of two treatments to investigate the effect of colostrum replacer (CR) feeding regimen on plasma volume (PV). Treatments were: (1) one feeding of CR (C₁; 3 L of reconstituted CR 675 g of powder providing 184.5 g of IgG at birth) or (2) two feedings of CR (C₂; 2 L of reconstituted CR at birth and 1 L of reconstituted CR at 6 h). By 6 h of age, all calves had received 3 L of CR providing 184.5 g of IgG. Plasma volume was estimated at 6, 12, 18, and 24 h after birth using Evans blue dye. No treatment effects were noted at any time points (P>0.05). Mean PV for all calves regardless of treatment at 6, 12, 18, and 24 h were 78.6, 89.2, 83.9, and 90.7 mL kg^-1 of body weight, respectively. Plasma volume was correlated with hematocrit (HCT), initial HCT, and treatment. Hematocrit was correlated with PV, initial HCT, and body weight. Hematocrit for 6, 12, 18 and 24 h after birth can be predicted with an initial precolostral HCT determination.

Ding, S., Oba, M., Swift, M. L., Edney, M., O'Donovan, J. T., McAllister, T. A. and Yang, W. Z. 2015. Short Communication: The effect of seed hardness and malting characteristics on in situ dry matter digestibility of barley grain in beef heifers. Can. J. Anim. Sci. 95: 299-303. An in situ study was conducted to evaluate the relationship between ruminal dry matter digestibility (DMD) and seed hardness or malting characteristics of barley grain. Samples were selected for low and high values of seed hardness index (53 vs. 65; N = 18), beta-glucan content in wort (122 vs. 316 ppm; N = 18), diastatic power (146 vs. 203°L; N = 18), and friability (46 vs. 81%; N = 18) in malt, and incubated in the rumen of three beef heifers for 4, 12 and 48 h. In situ DMD did not vary with beta-glucan concentration or friability. However, barley grain with low seed hardness had lower (P = 0.02) in situ DMD than those with high seed hardness after 4 h of incubation. The barley samples with low diastatic power also had (P = 0.02) higher DMD than with high diastatic power after 4 h, a trend (P = 0.07) that continued after 12 h of incubation. Seed hardness and malting characteristics may have the potential to predict DMD of barley grain in the rumen. However, observed differences in in situ DMD were relatively minor, and we did not detect a relationship between malting characteristics and in situ DMD at longer incubation times. This suggests that the identified grain physical and malt parameters may impact the rate, but not the extent of barley grain digestion in the rumen.

Sheppard, S. C., Bittman, S., Donohoe, G., Flaten, D., Wittenberg, K. M., Small, J. A., Berthiaume, R., McAllister, T. A., Beauchemin, K. A., McKinnon, J., Amiro, B. D., MacDonald, D., Mattos, F. and Ominski, K. H. 2015. Beef cattle husbandry practices across Ecoregions of Canada in 2011. Can. J. Anim. Sci. 95: 305-321. Beef production in Canada is diverse in many dimensions with numbers of cattle per operation ranging over 10 000-fold, pasture usage from nil to 100%, and types of operations from solely cow-calf to exclusively feedlot finishing. This study summarizes management information obtained from a survey conducted in 2012 (about 2011) on 1009 beef operations in Canada. Many of the results clearly differentiate the practices in the Prairies from those in Ontario and Quebec. Compared to eastern Canada, the Prairies had earlier and shorter calving seasons, higher weaning weights, utilized more winter grazing with a variety of strategies, grew and fed more barley than corn, used more seasonal feeding areas and feedlots (and hence fewer barns), and more commonly spread manure in the fall. Many of the management practices used by cow-calf operations would have low environmental impact, including extensive use of grazing even in winter, low fertilizer inputs and feeding perennial forages with a high content of legumes. Some practices such as not covering forages or manure storage structures were common and could be changed to improve forage quality and reduce manure emissions. Most forage was harvested 3-7 d after full bloom. Earlier harvest has the potential to improve forage quality, which could reduce dependence on arable crops. Finishing operations used more housing, fed more arable-land crops and less perennial forages, and practiced little grazing. Rationale regarding the adoption of many of the management strategies was reported by the producers. For example, winter grazing was adopted primarily to reduce costs and labour, but for some it was also linked to a late calving season. Preferred sources of technical information included their own experience, farm print media, producer organisations and demonstrations at field days. The survey also identified several areas in which the industry may realize improved sustainability.