Hristov, A. N., Hanigan, M., Cole, A., Todd, R., McAllister T. A., Ndegwa, P. and Rotz, A. 2011. Review: Ammonia emissions from dairy farms and beef feedlots. Can. J. Anim. Sci. 91: 1-35. Ammonia emitted from animal feeding operations is an environmental and human health hazard, contributing to eutrophication of surface waters and nitrate contamination of ground waters, soil acidity, and fine particulate matter formation. It may also contribute to global warming through nitrous oxide formation. Along with these societal concerns, ammonia emission is a net loss of manure fertilizer value to the producer. A significant portion of cattle manure nitrogen, primarily from urinary urea, is converted to ammonium and eventually lost to the atmosphere as ammonia. Determining ammonia emissions from cattle operations is complicated by the multifaceted nature of the factors regulating ammonia volatilization, such as manure management, ambient temperature, wind speed, and manure composition and pH. Approaches to quantify ammonia emissions include micrometeorological methods, mass balance accounting and enclosures. Each method has its advantages, disadvantages and appropriate application. It is also of interest to determine the ammonia emitting potential of manure (AEP) independent of environmental factors. The ratio of nitrogen to non-volatile minerals (phosphorus, potassium, ash) or nitrogen isotopes ratio in manure has been suggested as a useful indicator of AEP. Existing data on ammonia emission factors and flux rates are extremely variable. For dairy farms, emission factors from 0.82 to 250 g ammonia per cow per day have been reported, with an average of 59 g per cow per day (n=31). Ammonia flux rates for dairy farms averaged 1.03 g m^-2 h^-1 (n=24). Ammonia losses are significantly greater from beef feedlots, where emission factors average 119 g per animal per day (n=9) with values as high as 280 g per animal per day. Ammonia flux rate for beef feedlots averaged 0.174 g m^-2 h^-1 (n=12). Using nitrogen mass balance approaches, daily ammonia nitrogen losses of 25 to 50% of the nitrogen excreted in manure have been estimated for dairy cows and feedlot cattle. Practices to mitigate ammonia emissions include reducing excreted N (particularly urinary N), acidifying ammonia sources, or binding ammonium to a substrate. Reducing crude protein concentration in cattle diets and ruminal protein degradability are powerful tools for reducing N excretion, AEP, and whole-farm ammonia emissions. Reducing dietary protein can also benefit the producer by reducing feed cost. These interventions, however, have to be balanced with the risk of lost production. Manure treatment techniques that reduce volatile N species (e.g., urease inhibition, pH reduction, nitrification-denitrification) are also effective for mitigating ammonia emissions. Another option for reducing ammonia emissions is capture and treatment of released ammonia. Examples in the latter category include biofilters, permeable and impermeable covers, and manure incorporation into the soil for crop or pasture production. Process-level simulation of ammonia formation and emission provides a useful tool for estimating emissions over a wide range of production practices and evaluating the potential benefits of mitigation strategies. Reducing ammonia emissions from dairy and beef cattle operations is critical to achieving environmentally sustainable animal production that will benefit producers and society at large.

Oba, M. 2011. Review: Effects of feeding sugars on productivity of lactating dairy cows. Can. J. Anim. Sci. 91: 37–46. Sugars are water-soluble carbohydrates that are readily available in the rumen. Although sugars ferment faster than starch or fibre in the rumen, the rates of disaccharide hydrolysis and monosaccharide fermentation vary greatly depending on the type of sugar and rumen environment. Despite rapid fermentation in the rumen and their potential to provide greater fermentable energy to enhance microbial protein production, feeding sugars in place of dietary starch sources may not decrease rumen pH or improve N utilization efficiency and milk protein production in dairy cows. However, feeding high-sugar diets often increases dry matter intake, butyrate concentration in the rumen, and milk fat yield. These nutritional characteristics of sugars may allow us to use high-sugar feedstuffs as an alternative energy source for lactating dairy cows to increase dietary energy density with reduced risk of rumen acidosis, but there is little evidence in the literature to indicate that the synchrony of rumen fermentation would be enhanced by feeding high-sugar diets with high soluble protein. Greater butyrate production from feeding high-sugar diets is expected to enhance proliferation of gut tissues, but its physiological mechanisms and effects of butyrate metabolism on overall productivity of dairy cows warrant further investigations.

Greter, A. M. and DeVries, T. J. 2011. Effect of feeding amount on the feeding and sorting behaviour of lactating dairy cattle. Can. J. Anim. Sci. 91: 47–54. The objectives of this study were: (1) to determine how feeding amount affects feeding and sorting behaviour of dairy cows, and (2) to examine the relationship between these behaviours. Six lactating dairy cows were assigned to one of two treatments in a crossover design with 7-d periods: (1) lower feeding amount (target 5% orts), and (2) higher feeding level (target 15% orts). Cows were fed twice daily at 1000 and 1530. Treatments were imposed during the 18-h period between the afternoon feeding and the subsequent morning feeding. Treatment periods consisted of a 3-d adaptation period and a 4-d recording period, wherein feeding (using time-lapse video) and sorting behaviour were measured. Feed samples taken for particle size separation were separated into four fractions: long, medium, short, and fine particles. The targeted level of orts was not achieved, but treatments tended to be different (16.1 vs. 11.6%). Cows maintained similar feeding rates (0.1 kg min^-1), feeding times (209.0 min period^-1), and dry matter intake (DMI) (21.6 kg period^-1) between treatments. Cows sorted against long particles (67.3%) and tended to sort for short particles (104.4%) on both treatments. Across treatments, feeding rate was positively correlated with sorting of long particles (r=0.76). Feeding time was negatively correlated with sorting of short (r=-0.65) and fine (r=-0.68) particles. DMI tended to be positively correlated with sorting of long particles (r=0.48) and tended to be negatively correlated with sorting of short particles (r=-0.51). Meal duration tended to be negatively correlated with sorting of fine particles (r=-0.52). The results from this experiment provide new insight into how sorting behaviour may affect the time course of feeding, meal patterning, and nutrient intake of dairy cows.

Collings, L. K. M., Proudfoot, K. L. and Veira, D. M. 2011. The effects of feeding untreated and formic acid treated colostrum ad libitum on intake and immunoglobulin levels in dairy calves. Can. J. Anim. Sci. 91: 55–59. Newborn dairy bull calves were fed 4 L of colostrum by esophageal feeder or offered untreated or formic acid-treated colostrum ad libitum for 24 h; effects on intake, serum immunoglobulin G (IgG) levels and behavior were measured. The untreated ad libitum group consumed more colostrum (6 vs. 4 L) but had comparable serum IgG levels to the control (27.8 vs. 28.1 mg mL^-1). Adding formic acid to colostrum successfully reduced total bacteria and coliform counts; however, it reduced 24 h ad libitum consumption. Formic acid is not a practical preservation agent for colostrum offered ad libitum to newborn calves.

Nalaila, S. M., Stothard, P., Moore, S. S., Wang, Z. and Li, C. 2011. Whole genome fine mapping of quantitative trait loci for ultrasound and carcass merit traits in beef cattle. Can. J. Anim. Sci. 91: 61-73. Quantitative trait loci (QTL) mapped to large chromosomal regions have limited utility as DNA markers for marker-assisted selection (MAS) and are less informative as a reference for the identification of the underlying causative quantitative trait nucleotides (QTN). The objective of this study was to conduct a whole genome fine mapping of QTL for ultrasound and carcass merit traits in beef cattle using a greater density of single nucleotide polymorphism (SNP) markers, and to identify SNP markers within the QTL regions that are associated with the traits. A total of 418 steers from 28 sires were used in this study with nine ultrasound and seven carcass merit traits that were collected as part of a feedlot trial conducted from 2003 to 2005 at the University of Alberta Kinsella ranch. Sires and their progeny were genotyped for a total of 4592 SNP markers distributed across all 29 bovine autosomes (BTA). Across-family analyses detected 12 QTL for five ultrasound traits on nine chromosomes and 18 QTL for six carcass merit traits on 10 chromosomes (P<0.05). Within-family analyses identified 78 significant QTL for nine ultrasound and seven carcass merit traits (P<0.01). The use of a denser panel of SNP markers allowed fine mapping of QTL to smaller chromosomal regions ranging from 0.6 to 11 cM compared with relatively larger QTL regions of 4 to 24 cM reported in previous studies. Furthermore, single SNP marker association analyses identified 22 SNPs that were significantly associated with three ultrasound and four carcass merit traits under 12 QTL regions (P<0.05). These identified SNP markers significantly associated with the traits under the fine mapped QTL regions provide genomic tools for potential application of MAS and a reference to assist with the identification of QTN causing variations in ultrasound and carcass merit traits in beef cattle.

McLean, K. L. and Schmutz, S. M. 2011. Melanocortin 4 receptor polymorphism is associated with carcass fat in beef cattle. Can. J. Anim. Sci. 91: 75–79. Melanocortin 4 receptor (MC4R) binds a-melanocyte stimulating hormone (a-MSH) reducing feed and energy intake in several species of animals. One variant in swine has been reported to increase daily gain, backfat deposition and feed intake. MC4R sequence was obtained from 20 random crossbred steers where a novel Ser330Asn polymorphism was detected. Three hundred and eighty-two crossbred Canadian steers and 985 crossbred American steers were genotyped for this polymorphism. The Ser330Asn polymorphism had a minor allele frequency of 0.01 in the Canadian and 0.02 in the American steer populations. The Canadian steers with the heterozygous genotype had increased grade fat (P=0.036) and decreased lean meat yield (P=0.032). The American heterozygous steers had increased backfat (P=0.031) and less desirable yield grades (P=0.022), but also lower longissimus dorsi measurements (P=0.031). The association of the Asn330 allele was validated in two typical crossbred steer populations in two countries, suggesting it has effects of commercial significance.

Carruthers, C. R., Plante, Y. and Schmutz, S. M. 2011. Comparison of Angus cattle populations using gene variants and microsatellites. Can. J. Anim. Sci. 91: 81–85. Seven single nucleotide polymorphisms (SNP) in six genes (LEP, IGF2, MC1R, PMCH, CAPN1, and CAST), which have been previously associated with traits of economic importance, were used to compare allele frequencies of two populations of Angus cattle: a Canadian population and an International population. The same populations were also genotyped at 22 microsatellite markers. A significantly higher frequency of the CAST A allele, which is positively correlated with beef tenderness, was observed in the Canadian population (0.948) than in the International population (0.788; P = 0.007). Mean heterozygosity was higher for both populations using microsatellite data (0.578) compared with SNP data (0.332), due to the highly polymorphic nature of microsatellite markers

Khiaosa-ard R., Chungsiriwat P., Chommanart N., Kreuzer M. and Jaturasitha S. 2011. Enrichment with n-3 fatty acid by tuna oil feeding of pigs: changes in composition and properties of bacon and different sausages as affected by the supplementation period. Can. J. Anim. Sci. 91: 87–95. Belly, lean from the shoulder and backfat obtained from 80 pigs, fed either no or 1.6 kg tuna oil during fattening (35–90 kg body weight), were used to prepare bacon, Chinese-style sausage and Vienna-style sausage. The tuna oil had been supplemented either initially, at the end, or continuously during fattening. In all meat products, tuna oil supplementation clearly increased contents of n-3 fatty acids (FA), especially of the long-chain n-3 FA. Differences among supplementation periods were pronounced only in the n-3 FA proportion of total FA being lower with early tuna oil feeding. Thiobarbituric acid value, which was high in dry Chinese-style sausage, was mostly enhanced by tuna oil, whereas the period of tuna oil supplementation had no systematic influence. In conclusion, any mode of tuna oil supplementation investigated was efficient in enriching n-3 FA, but care should be taken in producing dry sausages due to their susceptibility to rancidity during storage time.

Lizaso, G., Beriain, M^a. J., Horcada, A., Chasco, J. and Purroy, A. 2011. Effect of intended purpose (dairy/beef production) on beef quality. Can. J. Anim. Sci. 91: 97–102. Fifteen Pirenaica (beef) heifers and fifteen Holstein-Friesian (dairy) heifers were compared to consider the effect of intended purpose of the breed on meat quality. Animals were slaughtered at around 12.4 mo of age. Carcass weight was 247.6 kg for Pirenaica and 229.2 kg for Holstein-Friesian heifers. pH_24hours, moisture, fat, protein, ash, water holding capacity, CIE L*a*b* and C* and H* values, collagen content, and shear force were determined in longissimus dorsi muscle. Sensory analysis of meat was performed to obtain the texture profile, scored by a trained taste panel. Sensorial differences of meat were mainly in relation to higher fat content observed in Holstein-Friesian (2.87%) vs. Pirenaica breed (1.82%) (P<0.01). Total and soluble collagen contents for the two breeds differed (P<0.01 and P<0.05, respectively) but did not result in different meat tenderness scores by taste panelists. Higher water-holding capacity in meat of Holstein-Friesian was observed (P<0.01). CIE L*a*b*, coordinates C* and H* values were not different between breeds. Sustained juiciness and oiliness were higher in Holstein-Friesian than Pirenaica (P<0.05 and P<0.01, respectively). Results suggest that beef characteristics of young heifers of dairy and beef breeds are similar with the exception of characteristics related to juiciness.

Bandegan A., Golian, A., Kiarie E., Payne R. L., Crow G. H., Guenter W. and Nyachoti C. M. 2011. Standardized ileal amino acid digestibility in wheat, barley, pea and flaxseed for broiler chickens. Can. J. Anim. Sci. 91: 103–111. Experiments were conducted to estimate ileal amino acids (AA) digestibility in six wheat (exp. 1; 288 birds), seven barley (exp. 2; 252 birds), five pea (exp. 3; 240 birds) and five flaxseed (exp. 4; 216 birds) samples in male Ross broiler chicks. Wheat, barley and pea were the sole source of dietary AA in exps. 1, 2 and 3, whereas, for exp. 4, flaxseed and wheat (50:50 wt/wt) or wheat provided dietary AA. Chromic oxide was the indigestible marker. Birds were fed chick starter for the first 14 d; on day 15 each test diet was randomly assigned to six cages, each with six (exps. 2 and 4) or eight (exps. 1 and 3) birds. On day 21, birds were killed and digesta were sampled to determine the apparent ileal AA digestibility (AID). The standardized ileal digestibility (SID) values were calculated using ileal endogenous AA losses previously determined in our laboratory from birds fed N-free diet. The mean SID values for indispensable AA ranged from 83.7% (Lys) to 93.8% (Phe), 80.4% (Arg) to 90.9% (Phe), 86.0% (Met Cys) to 94.2% (Arg) and 47.4% (Thr) to 66.7% (Met) for wheat, barley, peas and flaxseed samples, respectively. Overall, SID AA estimates for flaxseed had higher (> 13%) coefficients of variation (CV) compared with other ingredients (CV<6%). These SID AA data will help nutritionists to formulate broiler diets that more closely match the birds' requirements and minimize nutrient excretion.

Nikkhah, A., Furedi, C. J., Kennedy, A. D., Scott, S. L., Wittenberg, K. M. Crow, G. H. and Plaizier, J. C. 2011. Morning vs. evening feed delivery for lactating dairy cows. Can. J. Anim. Sci. 91: 113–122. A study was conducted to investigate the effects of changing feed delivery time from morning (0900) to evening (2100) on feed intake, diurnal feed intake patterns, digestion, rumen fermentation, milk production and composition, as well as on several blood metabolites. Eight (four ruminally cannulated) lactating Holstein cows, consisting of four primiparous and four multiparous cows, were used in the study. The change in the time of feed delivery increased the proportion of feed consumed within 3 h of feed delivery in all cows (54.7 vs. 46.3±4.1%, means±SE, P=0.05), but increased daily dry matter intake only in primiparous cows (18.5 vs. 20.4±0.7 kg d^-1, P=0.05). Average daily concentrations of blood glucose, lactate, urea and ß-hydroxybutyrate (BHBA) as well as rumen pH and concentrations of volatile fatty acids (VFA) were not affected by feed delivery time. However, rumen pH was lower (P<0.05), at 5 and 6 h after feed delivery, while total rumen VFA and acetate were higher (P<0.05) only at 6 h after feed delivery in cows fed in the evening. Also, compared with feed delivery at 0900, feeding cows at 2100 resulted in lower (P<0.05) blood glucose and urea at 2 h after feed delivery, and increased BHBA (P<0.05) at 4 and 6 h after feed delivery. Cows fed at 2100 tended to produce more milk fat than those fed at 0900 (1.11 vs. 0.97±0.07 kg d^-1, P=0.08). Milk yield and milk protein were not affected by the time of feed delivery. Changing the feed delivery time from morning to evening increased apparent total tract digestibility of dry matter, nitrogen, and neutral detergent fibre. The results of this study suggest that changing time of feed delivery from 0900 to 2100 increases feed consumption within 3 h after this delivery and rumen fermentation within 6 h after this delivery, changes diurnal patterns of glucose, urea and BHBA in peripheral blood, tends to increase milk fat, and increases nutrient digestibilities.

Van De Kerckhove, A. Y., Lardner, H. A., Yu, P., McKinnon J. J. and Walburger, K. 2011. Effect of dried distillers' grain, soybean meal and grain or canola meal and grain-based supplements on forage intake and digestibility. Can. J. Anim. Sci. 91: 123-132. Four ruminally cannulated beef heifers (72 wk of age) were individually fed a basal ration of 75% ground barley straw and 25% ground bromegrass hay [total digestible nutrients=46.3, crude protein (CP)=7.5 (% dry matter (DM))]. Heifers were supplemented with either (1) no supplement (CONT); (2) dried distillers' grains plus solubles [70:30 wheat:corn blend; dried distillers' grains plus solubles (DDGS)]; (3) commercial range pellet (COMM); or (4) barley grain and canola meal (BAR CM). Forage intake, apparent total tract digestibility, passage rate, rate and extent of forage degradation, rumen pH and rumen ammonia nitrogen were measured. Forage intake, passage rate, and apparent total tract digestibility of DM, neutral detergent fiber, and acid detergent fiber were unaffected (P>0.41) by treatment. Apparent total tract digestibility of CP was increased (P=0.02) with supplements as compared with CONT, but did not differ (P>0.05) among DDGS, COMM, and BAR CM. Ruminal pH was not affected (P=0.20) by treatment, but rumen ammonia-N was increased (P<0.01) with all three supplements. Potentially degradable and undegradable forage fractions were decreased (P<0.02) and there was a tendency (P=0.06) for the rate of forage DM degradation to increase with supplementation. Supplementing forage diets with either DDGS, grain-soybean-canola- or grain-canola-based supplements did not increase the intake or digestibility of a forage-based diet. More research, however, is required to study the feasibility of feeding these supplements at greater levels with forage-based beef cattle diets.

Addah, W., Baah, J., Groenewegen, P., Okine, E. K. and McAllister, T. A. 2011. Comparison of the fermentation characteristics, aerobic stability and nutritive value of barley and corn silages ensiled with or without a mixed bacterial inoculant. Can. J. Anim. Sci. 91: 133–146. Barley (Hordeum vulgare L.) and corn (Zea mays) silage are the most commonly used forages in feedlot diets in western Canada, and are often inoculated in an effort to improve their preservation and quality. However, the relative value of these two forages in feedlot diets or their responses to inoculation have not previously been compared. Whole-crop barley (B) and corn (C) forage were ensiled for 63 and 77 d, respectively, in both mini silos and Ag Bags® without and with inoculation [Lactobacillus plantarum, Enterococcus faecium, Pediococcus acidilactici at 1.0×10⁵ CFU g^-1 forage; inoculated barley (IB), inoculated corn (IC)]. At the end of the ensiling period in mini silos, the pH of C and IC was lower (P<0.001) than B and IB silage, but lactate:acetate was higher (P<0.001) in IB than other silages (8:1 vs. ~4:1). Inoculation did not affect dry matter (DM) loss during ensiling, but losses in barley were higher (P<0.001) than in corn silage. Barley silage appeared to be more stable than corn after 2 d of aerobic exposure. Inoculation of barley or corn did not affect in situ organic matter disappearance (OMD) or DM intake, average daily gain (ADG) or feed efficiency of steers. However, steers fed barley silage had a higher (P=0.037) DM intake, ADG (P=0.002) and improved (P=0.002) feed efficiency compared with those fed corn silage. The inoculant was more effective at improving the fermentation and aerobic stability of barley as compared with corn, and growth and feed efficiency of cattle fed barley silage was superior to those fed corn silage.

Mohammed, R., Khorasani, R. G., Goonewardene, L. A., Kramer, J. K. G. and Kennelly, J. J. 2011. Persistency of milk trans-18:1 isomers and rumenic acid in Holstein cows over a full lactation. Can. J. Anim. Sci. 91: 147-167. A long-term lactation study was undertaken to determine whether the previously reported short-term persistency in vaccenic acid [VA; trans(t)11-18:1] and rumenic acid (RA) could be maintained. To test this hypothesis, 24 Holstein cows were allotted to two experimental diets (control and test) from 2 wk before calving until they were 270 d in milk (DIM). The test diet was similar to the control diet, but supplemented with sunflower seed (11.2% diet DM), fish oil (0.5%) and monensin (22 mg/kg DM) by replacing an equivalent amount of barley grain. The forage: concentrate ratio was 50:50 (DM basis) with 35% barley silage and 15% alfalfa hay. Milk was sampled every fortnight from the start of lactation until cows were 270 DIM. Data obtained were averaged into three equal periods of 90 d each, representing three stages of lactation (SOL): early-lactation (EL), mid-lactation (ML) and late-lactation (LL). Dry matter intakes were not different between treatments with greater intakes observed during ML than during EL or LL. Milk yield was not different between treatments and decreased with increasing DIM. Milk fat content and yield showed interaction between treatment and SOL with lower values observed for the test diet than control diet during EL and ML. De novo synthesized fatty acids (4:0-15:0), 16:0-16:1 and preformed fatty acids (17:0 and above) showed interaction between treatment and SOL with the former two being greater for control diet than test diet and the latter greater for the test diet than control diet within each SOL. Milk t10-18:1 (% fatty acid methyl esters, FAME) was greater for the test diet compared with control diet (4.38 vs. 1.32) and was greater during ML (3.79) than during EL (2.38) or LL (2.38). Milk VA and RA showed interactions between treatment and SOL with greater values observed for the test diet than the control diet within each SOL. When analyzed by treatment, milk VA was not different across SOL for both diets. Milk RA was not different across SOL for the test diet, but was different for the control diet; it was lower during EL than during ML. Step-wise regression analysis revealed that the variability in milk RA for the control diet (P<0.01; R²=0.97) was determined by VA (70%) and RA/VA (27%); and for the test diet (P<0.01; R²=0.987) by VA (88.7%), RA/VA (5%) and t10-18:1 (3.8%). Desaturase index based on RA/VA showed an interaction between treatment and SOL; it was greater for the control diet than the test diet within each SOL. Overall findings revealed that the differences in milk t10- and VA across SOL reflected possible differences in starch and PUFA intakes, respectively. Differences in milk RA across SOL for the control diet could be attributed to possible differences in mammary desaturase activity based on differences in RA/VA.