Canadian Journal of Animal Science

Published by Agricultural Institute of Canada
Online ISSN: 0008-3984
Publications
Article
Background The prediction of the genetic disease risk of an individual is a powerful public health tool. While predicting risk has been successful in diseases which follow simple Mendelian inheritance, it has proven challenging in complex diseases for which a large number of loci contribute to the genetic variance. The large numbers of single nucleotide polymorphisms now available provide new opportunities for predicting genetic risk of complex diseases with high accuracy. Methodology/Principal Findings We have derived simple deterministic formulae to predict the accuracy of predicted genetic risk from population or case control studies using a genome-wide approach and assuming a dichotomous disease phenotype with an underlying continuous liability. We show that the prediction equations are special cases of the more general problem of predicting the accuracy of estimates of genetic values of a continuous phenotype. Our predictive equations are responsive to all parameters that affect accuracy and they are independent of allele frequency and effect distributions. Deterministic prediction errors when tested by simulation were generally small. The common link among the expressions for accuracy is that they are best summarized as the product of the ratio of number of phenotypic records per number of risk loci and the observed heritability. Conclusions/Significance This study advances the understanding of the relative power of case control and population studies of disease. The predictions represent an upper bound of accuracy which may be achievable with improved effect estimation methods. The formulae derived will help researchers determine an appropriate sample size to attain a certain accuracy when predicting genetic risk.
 
Article
The livestock sector is faced with an enormous challenge to meet the aspirations of the world’s population for increased availability of high-quality animal products in a sustainable manner while ensuring food safety, animal welfare and the maintenance of rare and specialist breeds. Two recent developments will be discussed that help meet this challenge. First, the quantitative models used in animal breeding can be extended to account for interactions among individuals kept in groups. The traditional quantitative genetic theory fails to explain why some traits do not respond to selection among individuals, but respond greatly to selection among groups. When applied to data on pigs and poultry, heritable variation was significantly greater than that obtained from classical analyses. Thus, a large part of the heritable variation was hidden to classical selection due to social interactions. Second, recent research on milk quality found large genetic variation between cows in fatty acid composition and protein composition of milk. Results clearly show that it is feasible to improve the composition of milk to better meet the needs of the cheesemaking industry and of consumers. Genomics assisted breeding offers opportunities for improving composition of milk in order to make optimum use of phenotypes on detailed milk composition which are expensive to collect. Both examples demonstrate that advances in animal breeding will continue to come from combining quantitative and molecular genetics
 
Article
The effects of including a waste chocolate confectionary product in swine diets on growth performance, carcass composition and meat quality of finishing pigs were determined. Four isocaloric, isonitrogenous diets were formulated to include 0, 10, 20 and 30% of a chocolate product in a pelleted corn and soybean-meal-based-diet and fed ad libitum to 32 gilts and 32 barrows from 54 kg to 105 kg. There were no significant differences among diets for average daily gain, feed intake and feed efficiency. Fat content in the diets increased from 3 to 7% with increasing inclusion, but there were no significant (P > 0.05) differences for backfat depth, total dissected fat, total lean or percent lean of the dissected carcass. With respect to meat quality, there were no significant differences observed for colour, structure and marbling of the loin and ham muscle. There were no treatment differences for the firmness of the inner backfat of pigs consuming the various diets. Waste chocolate confectionary can be fed to growing swine at inclusion levels up to 30% of the diet with no adverse effects on growth or carcass quality. Key words: Alternative feedstuff, chocolate, pigs, growth performance, carcass quality
 
Ingredients and chemical composition of the diets.
Phosphorus status of cows fed 0.36% P and 0.24% P at week 13 postpartum
Article
The effect of dietary P content on P balance was evaluated using 14 lactating dairy cows fed a corn silage based total mixed ration (TMR) containing either 0.24% P or 0.36% P. The animals were paired by calving date at dry-off with one cow from each pair randomly assigned to either dietary treatment. All cows were fed a common TMR containing 0.34% P prepartum, and then 0.41% P for 2 wk postpartum. Experimental diets were fed from 3 to 13 wk postpartum. Phosphorus balance was conducted at week 13 postpartum. Cows fed 0.36% P diet consumed more (P < 0.05) P than the 0.24% P diet cows (69.2 vs. 50.9 g d -1) and excreted more (P < 0.05) P in the faeces (49.1 vs. 25.7 g d-1). Phosphorus digestibility was lower (P < 0.05) for the 0.36% P diet than the 0.24% P diet (29.0 vs. 48.8%). Dry matter intake and milk yield were not (P > 0.05) affected by treatments. These results suggest that short-term P balance in lactating dairy cows can be maintained on a diet supplying 26% below National Research Council 2001 recommendations of P while reducing the amount of P excreted into the environment.
 
Article
This study was conducted to evaluate the effect of Enterococcus faecium (EF) and endo-1,4-β-xylanase (XY) in finishing pigs. The pigs were randomly divided into four treatments with eight replications per treatment and four pigs per pen in a 2 × 2 factorial arrangement with two levels of EF (0 or 0.1 g kg⁻¹ of feed) and XY (0 or 0.1 g kg⁻¹ of feed). During 0–12 wk, average daily gain and gain to feed ratio (G:F) increased by addition of EF in the diets (P < 0.05). The G:F increased by addition of XY in the diets (P < 0.05). At the 6th week, the results showed that digestibility of dry matter (DM), nitrogen, and energy increased with pigs fed EF supplemented diet compared with diets without EF supplementation (P < 0.05). In addition, administration of XY improved DM digestibility compared with treatments without XY supplementation (P < 0.05). The fecal Escherichia coli and Lactobacillus counts decreased and increased respectively by addition of EF or XY in the diets (P < 0.05). In conclusion, providing finishing pigs with diets that contained EF and XY can improve growth performance, nutrient digestibility, Lactobacillus population, and decrease E. coli counts.
 
The effect of treatment on ex vivo production of cytokines in supernatant of peripheral blood mononuclear cells of calves.
Article
The aims of this study were to investigate the effect of Saccharomyces cerevisiae var. boulardii CNCM I-1079 (SCB) or Lactobacillus acidophilus BT1386 (LA) on (1) innate immune response, (2) markers of acute-phase reaction, and (3) immune gene expression of rumen and ileum tissues of Holstein calves. Forty eight calves (∼5 d old) were randomly allocated to four treatments as follows: (1) control (CTRL) fed milk replacer followed by starter feed, (2) CTRL supplemented with SCB in milk and feed, (3) CTRL supplemented with LA in milk and feed, and (4) CTRL supplemented with antibiotics (ATB; chlortetracycline and neomycin in milk, and chlortetracycline in feed). Tumor necrosis factor α (TNF-α) decreased (P < 0.05) on day 66 (post-weaning) for the ATB-treated calves. There were no treatment effects on production of interferon γ (IFN-γ) and interleukin 6 (IL-6) proteins and on expression of TLR4, TLR6, TLR9, TLR10, CLDN3, MUC1, and MUC20 genes. Calves fed SCB or LA had a greater (P < 0.05) oxidative burst at weaning (day 53) compared with CTRL. Oxidative burst was also greater (P < 0.05) after weaning (day 59 and day 87) for SCB-fed calves. Calves fed SCB and ATB had higher (P < 0.05) phagocytosis activity during weaning (day 47) compared with CTRL. The concentration of serum amyloid A2 (SAA2) increased (P < 0.05) in SCB-and LA-fed calves (day 53), whereas the concentration of C-reactive protein (CRP) increased (P < 0.05) in SCB-fed calves during weaning as compared with CTRL. Our results suggest that SCB could improve innate immune response (oxidative burst and phagocytosis) and markers of acute-phase reaction (CRP and SAA2), especially during critical periods like weaning.
 
Article
Extruded flaxseed and ground hay [25% and 75%; dry matter (DM) basis] were fed in a total mixed ration (TMR) or sequentially (non-TMR) to three pens of eight crossbred steers per diet. At 112 d, erythrocytes from non- TMR steers had 65% more vaccenic acid (trans 11-18:1) than TMR steers (P < 0.05).
 
Overexpression of eIF5 upregulates β-casein expression. (A) Indicated proteins were detected by Western blotting analysis after eIF5 overexpression, β-actin was used as the loading control. Blank, normal cells; EV, empty control vector; eIF5 GO, eIF5 gene overexpression (pGCMV-IRES-EGFP-eIF5 vector). (B) Results of the relative fold of gray-scale scanning of indicated proteins. n = 3, **P < 0.01. (C) Proposed model depicting that 14-3-3γ interacts with and affects eIF5 to activate eIF2α for milk protein translation in BMECs in response to amino acid stimulation. The green arrow (→) denotes positive inputs; the red arrows (→) denote activation, the broken arrows denote unclear function. Figure appears in color on the Web.
Article
The 14-3-3γ protein participates in many biological processes; however, its regulatory mechanism in milk protein synthesis is not well studied. We hypothesized that 14-3-3γ might affect eIF5 (an initiation factor) to regulate β-casein synthesis in dairy cows. In this study, a possible interaction between 14-3-3γ and eIF5 was investigated using bovine mammary epithelial cells (BMECs). The expression levels of 14-3-3γ and eIF5 in the mammary gland tissues from cows producing higher quality milk were higher than those from cows producing low-quality milk. Moreover, the expression of 14-3-3γ, eIF5, and β-casein were increased at both mRNA and protein levels in BMECs cultured in vitro with methionine (Met) supplementation. Coimmunoprecipitation, colocalization, and FRET analysis further showed the evidences that 14-3-3γ physically bound to eIF5 in BMECs. Gene function studies revealed that 14-3-3γ positively regulated eIF5 through alteration of eIF2α/p-eIF2α ratio. Collectively, our data suggest that 14-3-3γ regulates β-casein translation in BMECs through interaction with eIF5.
 
Article
The Cornell Net Carbohydrate and Protein System model was used to formulate a low-protein mixed grass hay and corn diet predicted to create a ruminal N deficiency of 33% in 250-kg Holstein steers. Nitrogen metabolism, digestibility and metabolic status responses were compared between this control diet and a similar diet supplemented with 1.7% urea to compensate for the ruminal N deficiency. A 4 x 4 Latin square design was used to analyze main effects of diet and subcutaneous administration of 500 mug estradiol-17beta (E-2) twice a day. Urea supplementation increased N intake from 60 to 93 g d(-1), improved N balance from 10.1 to 17.7 g d(-1), and improved total tract digestibility of N, neutral detergent fiber (NDF), organic matter (OM), and dry matter (DM) (all P < 0.05), but there was no effect of urea supplementation on total tract digestibility of non-structural carbohydrate (NSC) and N retention (percent of N intake). Plasma urea N increased fourfold (P < 0.05) and plasma insulin increased from 0.32 to 0.50 ng mL(-1) (P = 0.06) when the urea diet was fed. Administration of E-2 did not alter N metabolism or plasma metabolites and insulin at either level of protein intake. It is concluded that supplementing a fiber-rich grass-hay-based diet with urea to achieve ruminal N balance increases digestibility of fiber fractions without altering dietary N utilization. Under these nutritional conditions the use of estrogenic growth promoters remains ineffective independent of ruminal N balance.
 
Article
Ilse, B. R., O'Neil, M. R., Lardy, G. P., Reynolds, L. P. and Vonnahme, K. A. 2012. Impacts of linseed meal and estradiol-17 beta 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, I, 7, or 14 d and implanted with estradiol-17 beta (E2) for 0, 6, or 24 h before tissue collection. There was an interaction of LSM x 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 I 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 x 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.
 
Article
There is a limited data available on the biology of guinea fowls. The objective of this study was to document post-hatch histological and stereological changes in the oviducts of 56 guinea hens and associated 17β-estradiol profiles until 32 wk of age and to explore changes in the oviducal mucosal fold as an index of oviducal growth. Mucosal folds in all regions of the oviduct increased significantly (P < 0.0001) from 4 to 28 wk of age. Concentrations of plasma 17β-estradiol increased from 20 to 28 wk of age, when it stabilized. Mucosal folds in the oviducts of sexually active hens were highest in the uterine region and lowest in the infundibular lip. Intercorrelations among 17β-estradiol concentration, height of mucosal folds, and oviducal weight were strong and positive in these birds. Most of the oviduct epithelium consisted of pseudostratified columnar ciliated epithelium. Both the height of oviducal folds and peripheral estradiol concentrations increased significantly from 20 to 28 wk of age, which confirms the role of estradiol in oviducal growth in the avian species. The height of oviducal mucosal folds appears to be a good measure of oviducal growth.
 
Article
To test the hypothesis that increased circulating estradiol increases hepatic glutamine synthetase (GS) content in young and aged cows, and two nonclassical nongenomic estradiol pathway intermediates [β-catenin, G protein-coupled receptor 30 (GPR30)], 12 young (3-4 yr) and 12 aged (≥8 yr) cows were randomly allotted (n = 6) and received either none or estradiol (TRT) implants (Compudose®) for 28 d. Blood and liver samples were collected on days 16 and 28 and the effects of TRT, cow age (age), time after implant (day), and their interactions were analyzed by analysis of variance (ANOVA). Plasma estradiol was increased by TRT in young and aged cows on days 16 and 28 and on day 28 vs. day 16. An age × day interaction (P = 0.01) revealed lower GS mRNA at day 28 in young cows but increased mRNA in aged cows. Aged cows had less GS protein than young cows, and a TRT × day interaction (P = 0.02) reflected 134% more of GS on day 16 in TRT in aged cows. No main or interaction effects were found for progesterone, β-catenin, or GPR30. We conclude that hepatic GS expression is transiently stimulated by increased circulating estradiol, whereas expression of β-catenin or GPR30 was not affected.
 
Article
There is a paucity of information on the reproductive biology of guinea hens. A study was conducted to document postembryonic developmental changes in the ovarian histology and associated progesterone and 17β-oestradiol profiles until 32 weeks of age (WOA). Highly significant increases (p<0.001) were noticed in oocyte and follicular diameters beyond 16 WOA. Other ovarian follicular morphometric traits showed inconsistent increases until 16 WOA. The first phase of yolk deposition occurred between hatching and 20 WOA, the second phase between 20 and 26 WOA, and the third and final phase between 27 and 28 WOA. Peripheral 17β-oestradiol concentrations increased from 20 WOA until it peaked at 28 WOA, while peripheral progesterone concentrations fluctuated considerably during sexual development. Both oestradiol and progesterone concentrations were negatively and moderately correlated (p<0.01) with oocyte nuclei diameter, granulosa and theca layer heights. However, oestradiol concentrations were positively and strongly correlated (p<0.001) with oocyte and follicular diameters, and moderately with progesterone concentrations. Three phases of yolk depositions were found in the guinea hen, with the final phase terminating at 28 WOA, at a much smaller oocyte diameter than in the domestic chicken. Oestradiol might play a role in yolk deposition in this species.
 
Article
Steers were fed a red clover silage-based diet with or without flaxseed to evaluate over time the effects of flaxseed supplementation on erythrocytes (ERC) trans(t)18:1 isomers composition and their relationships to adipose tissue and muscle t18:1 profiles at slaughter. Concentrations of most ERC t18:1 isomers in steers fed flaxseed increased (PB0.01) markedly in the first 2 mo and increased gradually thereafter. Strong (P<0.01) correlations of t9-, t10- and t11-18:1 isomers were observed from month 2 to 6 between ERC and beef tissues collected at slaughter from steers fed flaxseed. Findings suggest that ERC sampled as early as 2 mo into the feeding period can be indicative of variation in beef t18:1 isomeric profile at a later slaughter date when feeding red clover silage with flaxseed.
 
Article
The present study compared ammonia (NH 3 ) emissions from Canadian beef production in 1981–2011. Temporal and regional differences in cattle categories, feed types and management systems, average daily gains, carcass weights, and manure handling practices were considered. A scenario-based sensitivity analysis in 2011 estimated the impact of substituting corn dried distillers’ grains with solubles (DDGS) for grain in feedlot diets. On average, 22% of the total nitrogen (N) intake was lost as ammoniacal nitrogen (NH 3 -N) in both years. Manure emission sources were consistent across years, averaging 12%, 40%, 28%, and 21% for grazing, confinement, storage, and land spreading, respectively. Emissions per animal in 1981 and 2011 were 16.0 and 18.4 kg NH 3 animal ⁻¹ yr ⁻¹ , respectively. On an intensity basis, kilogram of NH 3 emitted per kilogram of beef decreased 20%, from 0.17 in 1981 to 0.14 in 2011. This reduction was attributed to increases in reproductive efficiency, average daily gain and carcass weight, and improved breeding herd productivity. In 2011, substituting DDGS for grain in feedlot diets increased total NH 3 emissions and losses per animal. Although addition of by-products from the bioethanol industry can lower diet costs, it will be at the expense of an increase in NH 3 emissions.
 
The correlation coefficient (r) of gene expression, muscle fiber (MF) density and area, intramuscular fat (IMF), and meat shear force (MSF).
Article
PPARγ2, PGC-1α, and MEF2C play an important role in skeletal muscle development and fat deposition. This study aimed to determine their mRNA expression levels in longissimus dorsi (Ld), semitendinosus (Se), and soleus (Sol) muscles of crossbred Simmental bulls and estimate their association with intramuscular fat (IMF) content and meat shear force (MSF). We measured the muscle fiber (MF) density and area, IMF content, and MSF of 6-, 12-, and 36-mo-old bulls. We found that the expression patterns differed with age: the PPARγ2 expression in the three muscles of 36-mo-old bulls was greater than that in the muscles of 6- and 12-mo-old bulls (P < 0.05). Furthermore, PGC-1α expression in Sol of 36-mo-old and MEF2C expression in Ld of 12-mo-old bulls were higher than those in the respective muscles of 6- and 12-mo-old bulls, and 6- and 36-mo-old bulls, respectively (P < 0.05). The MF area, IMF content, and MSF increased with age (P < 0.05). The PPARγ2 mRNA expression in Ld, Se, and Sol was positively correlated with MF area and IMF content (P < 0.05) and negatively correlated with MF density (P < 0.05). Thus, PPARγ2 might be a candidate marker, which is positively correlated with IMF content and MF area.
 
Article
Juarez, M., Larsen, I. L., Klassen, M. and Aalhus, J. L. 2013. Canadian beef tenderness survey: 2001-2011. Can. J. Anim. Sci. 93: 89-97. A large survey across Canada was developed collecting retail beef samples in 2001 (702 steaks) and 2011 (602 steaks). The samples (strip loin, top sirloin, inside round and cross-rib steaks) were evaluated for instrumental tenderness using standard procedures for sampling, storage, cooking and texture evaluation. New equations were also developed in order to compare the results obtained in these studies with consumer thresholds developed in Canada and the United States of America. In general, retail steaks collected in 2011 weighed less and showed higher fat thickness than those from 2001. Regarding tenderness, a significant improvement was observed, especially for strip loin and top sirloin steaks between 2001 and 2011. Using US threshold categories, the percentage of "tender" samples improved for the strip loin (2001=89%; 2011=99%), top sirloin (2001=70%; 2011=87%), inside round (2001=52%; 2011=61%) and cross-rib (2001=65%; 2011=76%) steaks. Similarly, the percentage of "tough" samples shifted from 5, 827 and 13% for the strip loin, top sirloin, inside round and cross-rib steaks in 2001 to I, 5, 13, and 8%, respectively, in 2011. Similar improvements were observed when using the more descriptive four-category Canadian threshold system. These improvements may be due to changes in the animal population, production systems, carcass processing and distribution/handling prior to display in Canada.
 
Article
The objective of this paper was to evaluate changes in management practices of beef cattle from 2005 to 2011. Large nationwide surveys of husbandry practices in the beef industry were conducted to represent management practices used in 2005 and 2011 across Canadian Ecoregions. The two surveys attempted to similarly represent operation types (cow–calf, backgrounding, and finishing) and size. Several statistically significant changes in management practices from 2005 to 2011 were observed: in non-feedlot operations, these included more operations with >50% legume in perennial forage, less N fertilization applied to forages, increased winter grazing of cows, and higher quality feed used as a supplement to grazing. In feedlots, there were more shelter structures, less feeding of grain and more of high-legume forages, and more frequent removal of manure. Several practices remained constant in the two surveys including use of covers for storing hay, frequency of harvesting forage, time of barn and feedlot cleanout, manure storage and practices relating to manure incorporation into soil. The large increase in use of winter grazing on the Prairies as well as in eastern Canada documented here is an important change in the industry that has both economic and environmental implications.
 
Article
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[1]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.
 
Article
This group meets yearly for one-day meetings. The 2013 meeting was sponsored by Nutreco Canada, Inc., Guelph, ON, Canada; ADM, Decatur, IL, USA; Cargill Animal Nutrition, Elk River, MN, USA; Ajinomoto Heartland, Inc., Chicago, IL, USA; Adisseo, Alpharetta, GA, USA; Lallemand Specialties, Inc., Milwaukee, WI, USA and Evonik Industries AG, Hanau, Germany. It was held on July 7 at the Hyatt Regency Indianapolis, One South Capital Avenue, Indianapolis, Indiana, USA, prior to the ADSA/ASAS Joint Annual Meeting. Summaries of the papers presented follow. Each summary has been peer reviewed and edited for clarity. The person who presented the paper is identified with an e-mail address.
 
Article
The feedlot industry in Brazil is still evolving, and some nutritional management recommendations adopted by nutritionists changes from year to year. The main objective of this survey was to provide a snapshot of current nutritional management practices adopted in Brazilian feedlots. The 33 nutritionists surveyed were responsible for approximately 4 228 254 animals. Corn remained as the primary source of grain used in feedlot diets by the participants, whereas fine grinding was the primary grain processing method. Corn silage was the primary roughage source indicated by nutritionists, and for the first time, physically effective neutral detergent fiber was the preferred fiber analysis method. The average dietary fat recommended was 50 g kg ⁻¹ of dry matter, which is about 10% higher than values reported in previous surveys. The use of truck-mounted mixers increased, which may have increased the percentage of feedlots using programmed feed delivery per pen, allowing the increase of energy content of finishing diets. Feedlots did not increase their capacity and nutritionists reported an improvement in feeding management. Results reported in the current study provide a baseline that can be used to improve practices and aid in the development of feedlot industry in Brazil and similar tropical climates.
 
Article
Two experiments were conducted to evaluate diet digestibility, performance, digestive parameters, and blood parameters when an enzyme complex (EC) was used in barley- and rye-based diets with different energy levels. In the digestibility assay (exp. I), 108 seventeen-day-old Cobb male broilers were distributed in a completely randomized design in 2 × 2 × 2 + 1 factorial arrangement with two feeds (barley or rye), two EC levels (0% and 0.02%), and two energy levels [3025 and 3125 kcal apparent metabolizable energy (AME)·kg ⁻¹ ], plus a control treatment. In exp. II, 1080 one-day-old Cobb male broilers were distributed in a completely randomized design in 2 × 2 × 2 + 1 factorial arrangement with two feeds (barley or rye), two EC levels (0% and 0.02%), and two energy levels (2875 and 2975 kcal AME·kg ⁻¹ ). No interactions were observed for any variables (exp. I and II). Enzyme complex improved the apparent metabolizable coefficient of gross energy (P = 0.0432) of diets. The EC provided greater weight gain (P = 0.0003) and better feed conversion (P = 0.0025). Intestinal viscosity at 21 d was reduced (P < 0.0001) with the addition of the EC. The EC improved nutrient digestibility and performance, but the effects of energy reduction on performance could not be overcome.
 
Article
Laying hens continue to improve in egg production (EP) and feed efficiency (FE), and therefore, it is relevant to re-examine their digestible balanced protein (BP) requirements. From 27 to 66 wk of age, hens (Lohmann-LSL Lite) were fed diets designed to provide 550, 625, 700, 775, or 850 mg hen ⁻¹ d ⁻¹ of amino acid balanced digestible lysine (Dlys). Response criteria included EP, egg weight (EW), feed intake (FI), mortality, egg mass (EM), egg size classifications, FE (kg feed kg ⁻¹ EM), and lysine efficiency (LE; mg Dlys g ⁻¹ EM). The experiment was a completely randomized design, and data were analyzed using regression analysis. Differences were considered significant if P ≤ 0.05. Hen-day (HD) EP, EW, EM, FI, and LE increased and FE and mortality decreased in a quadratic fashion with increasing Dlys intake, while the proportion of cracked eggs increased linearly. Egg size classifications increased linearly (jumbo, extra-large) and quadratically (large) or decreased in a quadratic manner (medium, small) with increasing Dlys intake. Maximum HDEP, EW, and EM, and minimum FE were achieved at 769, 903, 836, and 839 mg hen ⁻¹ d ⁻¹ intake of Dlys, respectively. In conclusion, the digestible BP requirement of laying hens varies with response criteria.
 
Article
The alpha (1) fucosyltransferase gene (FUT1) is a candidate gene for controlling the adhesion of Escherichia Coli (E.coli) F18 receptor. Indeed, a Single Nucleotide Polymorphism (SNP), c.307G>A, located in the gene is such that pigs with AA genotype are resistant to Entero-Toxigenic E.coli (ETEC) F18 while those with AG and GG genotypes are sensitive. An experiment was carried out in northern Vietnam from March 2016 to May 2017 to determine FUT1 genotype frequencies and effect of this genotypes on production performance of Yorkshire pigs. A total of 613 animals were genotyped using Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. The body weights at birth, weaning, initial and final fattening period were collected from 611, 516, 479, 418 animals respectively while backfat thickness, depth of longissimus dorsi and lean meat percentage were recorded from 328 animals. The frequencies of FUT1 genotypes were found to be in Hardy-Weinberg equilibrium (P=0.51). Effect of FUT1 genotype was not observed for all production traits (P>0.05) while final body weight and depth of longissimus dorsi were significantly different between females and males (P<0.05). These results suggest that selection of Yorkshire pigs resistant to ETEC E18 could be effective without adversely affecting average daily gain and lean meat.
 
Article
Tributyrin is a butyrate glyceride, shown to have positive effects on broiler performance. This study investigated the differences in growth performance between Ross 308 and Ross 708 birds, and compared how each strain responds to tributyrin supplementation. Two-hundred-and-forty-day-old Ross 308 and 240-d-old Ross 708 chicks were divided and fed a basal diet, or diets supplemented with low or high levels of tributyrin for 35 d. Neither strain nor tributyrin supplementation had an effect on average daily gain or feed:gain (P > 0.05). All Ross 708 birds had significantly decreased relative abdominal fat weight at 3 and 5 wk of age compared with Ross 308 birds of the same treatment (P ≤ 0.05). Tributyrin supplementation only decreased relative abdominal fat weight compared with controls in Ross 708 birds at 5 wk of age (P ≤ 0.05). Ross 708 control birds had significantly higher breast muscle fat deposition than Ross 308 controls (P ≤ 0.05), and tributyrin lowered this deposition in both strains (P ≤ 0.05). Significant differences in hepatic expression of genes associated with lipid metabolism were observed between strains, and with tributyrin supplementation (P ≤ 0.05). These results support the modulation of lipid metabolism by tributyrin, and show different broiler strains responded uniquely to tributyrin supplementation.
 
Article
The aim of this study was to evaluate the response of broiler breeder hens in terms of egg production to dietary nutrient intake. Using neural network (NN) models and breaking down the collected data from 98 commercial broiler breeder houses into 3-wk intervals, 10 NN-based models were developed from 31 to 60 wk of age. The data lines were divided into two random subsets of training (n=64) and testing (n=34) sets. The variables of interest for developing the models were metabolizable energy (ME; kcal bird-1 d-1), and crude protein (CP), total sulphur amino acids (TSAA), lysine (Lys), calcium (Ca) and available phosphorus (AP), all in g bird-1 d-1. The random optimization algorithm was applied to the constructed models to find the optimal level of the input variables which maximized egg production during the different intervals. The high R2 values in all the developed models for both the training and testing sets indicate the accuracy of NN-based models in estimating egg production. The optimization results revealed that breeder hens consuming 485, 473, 471, 466, 460, 452, 448, 442, 437 and 445 kcal of ME bird-1 d-1 showed the highest egg production during the 10 consecutive 3-wk intervals from 31 to 60 wk of age, respectively. Moreover, the optimal performance of hens required the following average intakes from 31 to 60 wk of age (g bird-1 d-1): CP: 23.7; TSAA: 1.05; Lys: 1.07; Ca: 4.91; and AP: 0.58. The results show that energy (kcal bird-1 d-1) and other nutrient requirements (g bird-1 d-1) of broiler breeder hens from 31 to 60 wk of age do not change in consort together with age; therefore using different diets with different dietary nutrient levels during the production cycle may help the nutritionists better meet the requirements of broiler breeder hens. Based on the present study, it appears that company guideline recommendations may underestimate the nutrient requirements of hens during these weeks when egg production is declining gradually.
 
Calf management adopted by dairy operations in Brazil according to consulting nutritionists surveyed.
Commodities and feeding frequency recommended for lactation diets according to the Brazilian consulting nutritionists surveyed.
Article
This work aimed to survey management practices used by dairy farmers and to report nutritional recommendations adopted by 43 dairy cattle nutritionists in Brazil. The web-based survey consisted of 80 questions. Almost 50% of the participants had clients that produce <1000 kg of milk daily and 48.8% had clients who own fewer than 100 dairy cows. Corn was the primary source of grain (97.4%), and 43.9% of the nutritionists included from 41% to 50% concentrate in lactation diets. The mean roughage inclusion in lactation diets was 50.5% and 79% of the nutritionists reported corn silage as the primary roughage source. Average crude protein and rumen-degradable protein concentrations recommended by the nutritionists for lactation diets were 15.7% and 9%, respectively. Average Ca and P concentrations recommended for lactation diets were 0.70% and 0.41%, respectively. The major health problem reported by 83.9% of the nutritionists was mastitis. The present survey provides an overview of management practices adopted by dairy farmers and nutritional recommendations currently applied by dairy cattle nutritionists in Brazil. The most critical points identified were low milk yield, mastitis as the major health problem, lack of proper mixing and delivery of rations, and destination of male calves.
 
Experimental diets composition, as-fed basis.
Analyzed chemical composition of experimental diets, as-fed basis.
Article
Production and metabolic consequences of feeding 49-wk-old Shaver white hens a high-energy low-crude-protein (HELP) diet were investigated over 6 wk. The test diets included standard diet [2750 kcal kg ⁻¹ apparent metabolizable energy (AME) and 17.5% crude protein (CP)], HELP (3000 kcal kg ⁻¹ of AME and 13.0% CP) diet, and HELP top dressed with selenium (HELP + Se). All diets had 0.3 mg Se kg ⁻¹ as part of premix. Hens (33) were procured, three birds necropsied for baseline liver samples, and the rest placed in individual cages and allocated diets (n = 10). Feed intake (FI), hen day egg production (HDEP), and egg weight (EW) were monitored weekly. Plasma and liver samples were collected from all birds. Birds fed standard and HELP diets had similar (P > 0.05) FI (with exception of weeks 4 and 5) and HDEP, whereas HELP + Se depressed (P < 0.05) feed and nutrient intake at weeks 5 and 6, HDEP, and EW. There were no (P > 0.05) diet effects on hepatic weight and crude fat content. Birds fed HELP diets had lower (P > 0.05) concentration of plasma total protein, macrominerals, and some enzymes. Overall, HELP diet had minimal impact on production and metabolism; however, addition of Se had negative effects on hen performance.
 
Effect of total levels of methionine and cysteine (Met + Cys) on performance of laying hens within 24-48 wk of age. a
Article
Using 960 brown laying hens from 20 to 48 wk of age, in a 4 × 5 factorial arrangement, the effects on production, quality of eggs, and nutrient balance of analysed 18, 41, 61, and 111 mg kg ⁻¹ of copper (Cu) and of 0.550%, 0.679%, 0.793%, 0.845%, and 0.948% of methionine and cysteine (Met + Cys) were evaluated. Treatments were administered to six replicate cages (eight hens per cage). At the 49th wk of age, 320 of these hens were kept under the same experimental conditions to evaluate the nutrient balance, and each treatment was allocated to four replicate cages (four hens per cage). The trend of interaction effect between Cu and Met + Cys levels was observed on egg weight and mass. The interaction between mineral and amino acid was characterized on egg quality variables. Quadratic equations indicated that increasing the dietary level of Cu reduced the estimate requirement of Met + Cys for hens. Across the entire experimental period, the total estimated Met + Cys level was 0.755% ± 0.021% based on the performance variables. As Cu increased in the diet, it decreased the estimated Met + Cys level to ensure egg weight, mass, and egg quality. Level of chelated Cu above 23 mg kg ⁻¹ may negatively affect the egg quality.
 
Article
This study examined the feasibility and accuracy of using Illumina BovineSNP50 genotypes to estimate individual cattle breed composition and heterosis relative to estimates from pedigree. First, pedigree was used to compute breed fractions for 1,124 crossbred cattle. Given the breed composition of sires and dams, retained heterosis and retained heterozygosity was computed for all individuals. Second, all animals’ genotypes were used to compute individual’s genomic breed fractions by applying a cross-validation method. Average genome-wide heterozygosity and retained heterozygosity based on genomic breed fraction was computed. Lastly, accuracies of breed composition, retained heterozygosity and retained heterosis were assessed as Pearson’s correlation between pedigree- and genome-based predictions. The average breed composition observed were 0.52 Angus, 0.23 Charolais and 0.25 Hereford for pedigree-based and 0.46, 0.26, 0.28 for genome-based predictions, respectively. Correlations of predicted breed composition ranged from 0.94 to 0.96. Genome-based retained heterozygosity and retained heterosis from pedigree were also highly correlated (0.96). A positive association of non-additive genetic effects was observed for growth traits reflecting the importance of heterosis for these traits. Genomic prediction can aid analyses that depend on knowledge of breed composition and serve as a reliable method to predict heterosis to improve the efficiency of commercial crossbreeding schemes.
 
Article
In the present study, we cloned and characterized the HSP60 cDNA from Anas platyrhyncho (designated as ApHSP60) using a combination of homology and rapid amplification of cDNA ends (RACE). The full-length of ApHSP60 is 2 027 bp in length, with an open reading frame of 1 707 bp encoding a putative protein of 569 amino acids. Comparison of amino acid sequences of HSP60 revealed ApHSP60 is highly conserved, especially in the domains of classical HSP60 family signatures. ApHSP60 transcripts were at low expression levels throughout embryo development. ApHSP60 transcripts were constitutively expressed in all tested tissues of untreated laying duck, with a maximum level in the liver. Fluorescent real-time quantitative reverse transcription-polymerase chain reaction was applied to determine ApHSP60 expression after exposure to different thermal shocks. Under long term treatment with both 30°C and 35°C, ApHSP60 transcripts in heart and liver were significantly up-regulated. Otherwise, ApHSP60 transcripts were remarkably down-regulated in heart and liver under acute challenge with 40°C (a fatal temperature for laying duck). A time-dependent expression pattern of ApHSP60 was found in the recovery period after heat shock reaction. ApHSP60 expression levels in liver and heart were immediately up-regulated to the maximum at 1 h post-challenge, and then decreased to pre-challenge levels by 2 h and 3 h post-challenge, respectively. These results suggest that mRNA expression of the ApHSP60 gene is constitutive and inducible. Meanwhile, it plays an important role in response to heat stressors.
 
Article
Yanbian yellow cattle breeding is limited by its slow growth. We previously found that the miRNA miR-6523a is differentially expressed between Yanbian yellow cattle and Han Yan cattle, which differ in growth characteristics. In this study, we evaluated the effects of miR-6523a on growth hormone (GH) secretion in pituitary cells of Yanbian yellow cattle. Bioinformatics analyses using TargetScan and RNAhybrid as well as dual luciferase reporter assays showed that miR-6523a targets the 3' UTR of SSTR5 (somatostatin receptor 5). We further found that the mRNA and protein expression levels of GH in pituitary cells were significantly higher in cells treated with miR-6523a mimic than in the control group (P=0.0082 and P=0.0069). GH mRNA and protein expression levels were lower in cells treated with miR-6523a inhibitor than in the control group, but the difference was not significant (P=0.064 and P=0.089). SSTR5 mRNA and protein levels were inhibited by miR-6523a mimic compared with the control group) (P=0.0024 and P=0.0028) and were elevated slightly by miR-6523a inhibitor (P=0.093 and P=0.091). These results prove that miR-6523a regulates GH secretion in pituitary cells by SSTR5. More broadly, these findings provide a basis for studies of the roles of miRNAs in animal growth and development.
 
Article
Ten Jersey steers (484 +/- 55 kg) were fed a basal diet of 70% rolled barley grain and 30% alfalfa silage [dry matter (DM) basis] with or without additives, in a replicated 5 x 5 Latin square experiment. Treatments (additives per kilogram dietary DM) were: C, no additives (control); T, Tween 80 (2 g kg(-1)); SH, salinomycin (13 mg kg(-1)); TSM, Tween 80 (2 g kg(-1)) plus salinomycin (6.5 mg kg(-1)); and TSL, Tween 80 (2 g kg(-1)) plus salinomycin (3.25 mg kg(-1)). Ruminal pH, concentrations of ammonia, total free amino acids, reducing sugars and total volatile fatty acids (VFA), and fluid phase viscosity were unaffected (P > 0.05) by treatment. Ruminal carboxymethylcellulase, xylanase and amylase activities, numbers of protozoa, and outflow rates of the liquid and solid phases of ruminal contents did not differ (P > 0.05) among treatments. Ruminal lactic acid bacteria populations tended (P < 0.1) to be smaller with SH compared with C, but counts were unaffected (P > 0.05) by T, TSL and TSM. Partitioning of ruminal digesta and microbial protein flow were similar (P > 0.05) among treatments. Compared with C, the ruminal rate of degradation tin situ) of alfalfa DM tended to be higher (P < 0.10) with SH, and the rate of barley grain DM degradation was higher (P < 0.05) with T. Intake and apparent digestibilities of DM, neutral detergent fibre (NDF), acid detergent fibre (ADF) and crude protein were unaffected (P > 0.05) by treatment, as were blood glucose and urea levels. Tween 80 and salinomycin did not affect ruminal fermentation or nutrient digestibility in steers fed a barley grain/alfalfa silage diet.
 
Article
The objective of this study was to determine the early responses to a moderate concentrate increase in the diet with regards to various behavioral and physiological responses in cattle. Eight ruminally-cannulated Angus crossbred beef heifers were adapted to a 70% concentrate diet (T70) and then switched to a 90% concentrate diet. Measurements of feeding behavior, ruminal pH and temperature, rumen motility, liquid passage rate, and blood acid-base status were conducted on T70 as well as first (d1 H90) and second (d2 H90) days of high-grain feeding to monitor the beginning of the transition period. Ruminal pH was below 5.6 for longer on both days of H90 compared to T70 and suggested animals experienced subacute ruminal acidosis while switching from T70 to H90. Transitioning did not affect dry matter intake (DMI). Eating rate during meals was reduced on d1 and d2 H90 compared to T70. Ruminal contraction amplitude was reduced on both days of H90 feeding. Contraction duration was reduced on d1 H90, and returned to T70 values by d2 H90. Results indicated that a moderate transition to a finishing diet influenced feeding behavior and reduced rumen motility at the beginning time after transition but did not influence voluntary DMI.
 
Top-cited authors
John A Basarab
  • University of Alberta
Karen A Beauchemin
  • Agriculture and Agri-Food Canada
Tim A Mcallister
  • Agriculture and Agri-Food Canada, Canada, Lethbridge
Erasmus K Okine
  • University of Alberta
John Mckinnon
  • University of Saskatchewan