Showing papers in "Journal of Animal Science in 2017"

The microbiota-gut-brain axis as a key regulator of neural function and the stress response: Implications for human and animal health.

Abstract: The brain-gut-microbiota axis comprises an extensive communication network between the brain, the gut, and the microbiota residing there. Development of a diverse gut microbiota is vital for multiple features of behavior and physiology, as well as many fundamental aspects of brain structure and function. Appropriate early-life assembly of the gut microbiota is also believed to play a role in subsequent emotional and cognitive development. If the composition, diversity, or assembly of the gut microbiota is impaired, this impairment can have a negative impact on host health and lead to disorders such as obesity, diabetes, inflammatory diseases, and even potentially neuropsychiatric illnesses, including anxiety and depression. Therefore, much research effort in recent years has focused on understanding the potential of targeting the intestinal microbiota to prevent and treat such disorders. This review aims to explore the influence of the gut microbiota on host neural function and behavior, particularly those of relevance to stress-related disorders. The involvement of microbiota in diverse neural functions such as myelination, microglia function, neuronal morphology, and blood-brain barrier integrity across the life span, from early life to adolescence to old age, will also be discussed. Nurturing an optimal gut microbiome may also prove beneficial in animal science as a means to manage stressful situations and to increase productivity of farm animals. The implications of these observations are manifold, and researchers are hopeful that this promising body of preclinical work can be successfully translated to the clinic and beyond.

Probiotic supplementation protects weaned pigs against enterotoxigenic Escherichia coli K88 challenge and improves performance similar to antibiotics

Abstract: These studies evaluated the effects of probiotics (PB) as a potential substitute for antibiotics (AB) on diarrhea in relation to immune responses and intestinal health in weaned pigs challenged with enterotoxigenic (ETEC) K88 (Exp. 1) and the effects of PB on performance and nutrient digestibility in weaned pigs (Exp. 2). In Exp. 1, 24 weaned barrows (4.9 ± 0.4 kg initial BW) were randomly assigned to 1 of 4 treatments. The treatments consisted of pigs fed an unsupplemented corn-soybean meal basal diet and not challenged (NON-C) or challenged with ETEC K88 (CHA-C) on d 9 and pigs fed the same basal diet supplemented with AB (100 mg/kg zinc bacitracin, 50 mg/kg colistin sulfate, and 100 mg/kg olaquindox; CHA-AB) or 500 mg/kg PB ( and ; CHA-PB) and challenged with ETEC K88 on d 9. In Exp. 2, 108 weaned pigs (7.5 ± 0.9 kg initial BW) not challenged with ETEC K88 were randomly assigned to 1 of 3 treatments, including an AB-free basal diet (CON) and the basal diet with AB (ABD) or 500 mg/kg PB supplementation (PBD). In Exp. 1, after challenge, CHA-C decreased ( < 0.05) ADG and ADFI, whereas CHA-AB and CHA-PB revealed no significant change compared with NON-C. Compared with CHA-C, CHA-AB and CHA-PB improved ( < 0.05) ADG and ADFI and decreased ( < 0.05) the diarrhea incidence in pigs. Mucosal secretory Ig A contents in the jejunum and ileum were greater in CHA-C than in NON-C ( < 0.05) and lower than in CHA-PB ( < 0.05). The diet containing PB alleviated the increase in the endotoxin and diamine oxidase concentration and cecal count ( < 0.05) and the decrease in intestinal villus height, cecal count, and jejunal mucosal occludin protein abundance ( < 0.05). In Exp. 2, dietary supplementation with AB and PB had positive effects on ADG and feed efficiency ( < 0.05). Compared with CON, apparent digestibility of nutrients in PBD was improved ( < 0.05). Collectively, PB supplementation protected the pigs against ETEC K88 infection by enhancing immune responses and attenuating intestinal damage and improved the performance and nutrient digestibility of weaned pigs. Therefore, PB could be a potential effective alternative to AB for ameliorating diarrhea and improving performance in weaned pigs.

Use of GPS tracking collars and accelerometers for rangeland livestock production research

Abstract: Over the last 20 yr, global positioning system (GPS) collars have greatly enhanced livestock grazing behavior research Practices designed to improve livestock grazing distribution can now be accurately and cost effectively monitored with GPS tracking For example, cattle use of feed supplement placed in areas far from water and on steep slopes can be measured with GPS tracking and corresponding impacts on distribution patterns estimated Ongoing research has identified genetic markers that are associated with cattle spatial movement patterns If the results can be validated, genetic selection for grazing distribution may become feasible Tracking collars have become easier to develop and construct, making them significantly less expensive, which will likely increase their use in livestock grazing management research Some research questions can be designed so that dependent variables are measured by spatial movements of livestock, and in such cases, GPS tracking is a practical tool for conducting studies on extensive and rugged rangeland pastures Similarly, accelerometers are changing our ability to monitor livestock behavior Today, accelerometers are sensitive and can record movements at fine temporal scales for periods of weeks to months The combination of GPS tracking and accelerometers appears to be useful tools for identifying changes in livestock behavior that are associated with livestock diseases and other welfare concerns Recent technological advancements may make real-time or near real-time tracking on rangelands feasible and cost-effective This would allow development of applications that could remotely monitor livestock well-being on extensive rangeland and notify ranchers when animals require treatment or other management

Feed efficiency phenotypes in lambs involve changes in ruminal, colonic, and small-intestine-located microbiota.

Abstract: Montana Agricultural Experiment Station (project MONB00113); National Institute of General Medical Sciences of the National Institutes of Health (NIH-NIGMS: award number P20GM103474); Enhancing the Competitiveness of U.S. Beef (MONB00195); Multistate Research Project (W3177, W2010); Integrated Approach to Enhance Efficiency of Feed Utilization in Beef Production Systems (MONB00196)

Disappearance of nutrients and energy in the stomach and small intestine, cecum, and colon of pigs fed corn-soybean meal diets containing distillers dried grains with solubles, wheat middlings, or soybean hulls.

Abstract: Disappearance of nutrients and energy in the stomach and small intestine, cecum, and colon of pigs fed diets containing distillers dried grains with solubles (DDGS), wheat middlings, or soybean hulls was determined. A second objective was to test the hypothesis that physical characteristics of dietary fiber in diets are correlated with the digestibility of nutrients and energy. Eight barrows (initial BW = 37.3 ± 1.0 kg) with a T-cannula in the distal ileum and another T-cannula in the proximal colon were allotted to a replicated 4 × 4 Latin square design with 4 diets and 4 periods in each square. The basal diet was a corn-soybean meal diet and 3 additional diets were formulated by substituting 30% of the basal diet with DDGS, wheat middlings, or soybean hulls. Following an 8-d adaptation period, fecal samples were collected on d 9 and 10, and samples from the colon and the ileum were collected on d 11 and 12, and d 13 and 14, respectively. Values for apparent ileal digestibility (AID), apparent cecal digestibility (ACD), and apparent total tract digestibility (ATTD) of nutrients and energy were calculated. Results indicated that ACD and ATTD of soluble dietary fiber was not different regardless of diet indicating that the soluble dietary fiber is mostly fermented in the small intestine or in the cecum. Pigs fed the wheat middlings diet had greater ( ≤ 0.05) ACD of insoluble dietary fiber compared with pigs fed diets containing DDGS or soybean hulls indicating that the insoluble fiber in wheat middlings may be more fermentable than insoluble fiber in DDGS or soybean hulls. Insoluble dietary fiber disappearance in the colon of pigs fed the soybean hulls diet was greater ( ≤ 0.05) compared with the DGGS containing diet indicating that insoluble fiber in DDGS are more resistant to fermentation than insoluble fiber in soybean hulls. The ATTD of total dietary fiber in wheat middlings was greater ( ≤ 0.05) than in DDGS and soybean hulls further indicating that fiber in wheat middlings are more fermentable than fiber in DDGS and soybean hulls. Water binding capacity, bulk density, and viscosity of dietary fiber were not correlated with digestibility of nutrients and energy regardless of the diet. In conclusion, soluble dietary fiber is mostly fermented before reaching the colon whereas insoluble dietary fiber is mostly fermented in the colon, but fiber in wheat middlings is more fermentable than fiber in DDGS or soybean hulls.

Effects of Lactobacillus reuteri LR1 on the growth performance, intestinal morphology, and intestinal barrier function in weaned pigs.

Abstract: The objective of this study was to investigate the effects of Lactobacillus reuteri LR1, a new strain isolated from the feces of weaned pigs, on the growth performance, intestinal morphology, immune responses, and intestinal barrier function in weaned pigs. A total of 144 weaned pigs (Duroc × Landrace × Yorkshire, 21 d of age) with an initial BW of 6.49 ± 0.02 kg were randomly assigned to 3 dietary treatments with 8 replicate pens, each of per treatment and 6 pigs. Pigs were fed a basal diet (CON, controls), the basal diet supplemented with 100 mg/kg olaquindox and 75 mg/kg aureomycin (OA) or the basal diet supplemented with 5 × 1010 cfu/kg L. reuteri LR1 for a 14-d period. At the end of study, the ADG, ADFI, and G:F were calculated, and 1 randomly selected pig from each pen was euthanized for sample collection. The LR1 increased ADG (22.73%, P < 0.05) compared with CON. The villus height of the ileum was increased (P < 0.05) and crypt depth in duodenum was reduced (P < 0.05), along with increased (P < 0.05) villus height to crypt depth ratio of the jejunum and ileum by LR1 compared with CON and OA. LR1 increased (P < 0.05) ileal mucosal content of IL-22 and transforming growth factor-β compared with OA. Compared with CON, LR1 increased (P < 0.05) and OA decreased (P < 0.05) the ileal content of secretory immunoglobulin A (sIgA), and the abundance of transcripts of porcine β-defensin 2 and protegrin 1-5. Compared with CON, LR1 increased (P < 0.05) tight junction protein zonula occludens-1 and occludin transcripts in the mucosa of the jejunum and ileum, and those of mucin-2 in ileal mucosa. The relative expression of toll-like receptor 2 (TLR2) and TLR4 were increased (P < 0.05) in ileal mucosa in pigs fed LR1 compared with CON. In conclusion, these data indicated that dietary LR1 supplementation at 5 × 1010 cfu/kg improved growth performance, intestinal morphology, and intestinal barrier function in weaned pigs.

Dietary supplemented antimicrobial peptide microcin J25 improves the growth performance, apparent total tract digestibility, fecal microbiota, and intestinal barrier function of weaned pigs.

Abstract: Microcin J25 (MccJ25) is an antimicrobial peptide produced by a fecal strain of Escherichia coli containing 21 AA. This study was performed primarily to evaluate the effects of MccJ25 as a potential substitute for antibiotics (AB) on growth performance, nutrient digestibility, fecal microbiota, and intestinal barrier function in weaned pigs. In the present study, 180 weaned pigs (7.98 ± 0.29 kg initial BW) were randomly assigned to 1 of 5 treatments, including a basal diet (CON) and CON supplemented with AB (20 mg/kg colistin sulfate; ABD) or 0.5, 1.0, and 2.0 mg/kg MccJ25. On d 0 to 14, dietary supplementation with MccJ25 and ABD had positive effects on ADG, ADFI, diarrhea incidence, and G:F ( < 0.05). Pigs fed the 2.0 mg/kg MccJ25 diet had greater ADG ( < 0.05) and marginally greater G:F ( < 0.10) compared with pigs fed the ABD diet. Compared with the CON diet, the 2.0 mg/kg MccJ25 diet sharply improved ( < 0.05) ADG and G:F and decreased ( < 0.05) diarrhea incidence (d 15 to 28 and d 0 to 28). Apparent digestibility of nutrients in pigs fed 1.0 and 2.0 mg/kg MccJ25 was improved ( < 0.05) compared with that of pigs fed CON and ABD. The serum cytokines IL-6 and IL-1β and tumor necrosis factor-α levels in pigs fed MccJ25 were greater than in pigs fed CON ( < 0.05). Additionally, the IL-10 concentration in pigs fed MccJ25 was sharply increased ( < 0.05) compared with that of pigs fed CON. Pigs fed 1.0 and 2.0 mg/kg MccJ25 diets had remarkably decreased lactate, diamine oxidase, and endotoxin concentrations and fecal numbers ( < 0.05) and improved fecal and numbers ( < 0.05). Compared with the ABD diet, the diet containing 2.0 mg/kg MccJ25 did not increase lactate, diamine oxidase, and endotoxin (d 14) concentrations ( < 0.05) or decrease the and (d 28) numbers ( < 0.05). The diets containing 1.0 and 2.0 mg/kg MccJ25 and ABD (d 28) improved lactate concentration and short-chain fatty acid concentrations, including acetate, propionate, and butyrate, in feces ( < 0.05). Moreover, the pigs fed 2.0 mg/kg MccJ25 had greater lactate, butyrate (d 14), and propionate concentrations than the pigs fed the ABD diet ( < 0.05). In conclusion, dietary supplemented MccJ25 effectively improved performance, attenuated diarrhea and systematic inflammation, enhanced intestinal barrier function, and improved fecal microbiota composition of weaned pigs. Therefore, MccJ25 could be a potential effective alternative to AB for weaned pigs.

Efficient single-step genomic evaluation for a multibreed beef cattle population having many genotyped animals.

Abstract: An equivalent computational approach called ssGTBLUP was formulated for the original single-step GBLUP (ssGBLUP). In ssGTBLUP, the genomic relationship matrix has the form G = ZZʹ + C, where the (centered and scaled) Z marker matrix has size n x m (numbers of genotypes and markers), and the C matrix can be easily inverted. The inverse can be written as G-1 = C-1 − TʹT where T is an m by n matrix. When the preconditioned conjugate gradient (PCG) method is used to solve the mixed model equations, a matrix vector product G-1d needs to be computed. In ssGBLUP, this requires n2 multiplications, but in ssGTBLUP, the product TʹTd has 2nm multiplications and C-1d has cn multiplications with the constant c independent of n or m. In an approximate approach called ssGTBLUP(p), the eigendecomposition of ZʹC-1Z is used to reduce the number of rows in the T matrix. Here, p is the percentage of total variance explained by the accepted eigenvalues. The objective of this study was to compare the performance of ssGBLUP, ssGTBLUP, ssGTBLUP(p), and the APY (algorithm for proven and young) method. In APY, the core had 50,000 (APY50K), 30,000 (APY30K), or 10,000 (APY10K) animals. The approaches were tested on the Irish beef carcass conformation genetic evaluation which has a heterogeneous multibreed population. The pedigree had 13.3 million animals. There were m = 54,620 markers available from n = 163,277 genotyped animals. For genotyped animals, the correlations of breeding values between ssGBLUP and ssGTBLUP(p) for the 11 traits in the model ranged from 0.999–1.000 for p = 99, 0.998–1.000 for p = 98, and 0.992–0.998 for p = 95 but were 0.994–1.000 for APY50K, 0.969–0.997 for APY30K, and 0.899–0.967 for APY10K. Computing times per iteration were 4.43, 3.30, 2.69, 2.29, 1.55, 1.76, 1.27, and 0.55 min for ssGBLUP, ssGTBLUP, ssGTBLUP(99), ssGTBLUP(98), ssGTBLUP(95), APY50K, APY30K, and APY10K, respectively. The ssGTBLUP(p) approach allowed a well-defined approximation to ssGBLUP and fast computations

Selection on resilience improves disease resistance and tolerance to infections.

Abstract: Response to infection in animals has 2 main mechanisms: resistance (ability to control pathogen burden) and tolerance (ability to maintain performance given the pathogen burden). Selection on disease resistance and tolerance to infections seems a promising avenue to increase productivity of animals in the presence of disease infections, but it is hampered by a lack of records of pathogen burden of infected animals. Selection on resilience (ability to maintain performance regardless of pathogen burden) may, therefore, be an alternative pragmatic approach, because it does not need records of pathogen burden. Therefore, the aim of this study was to assess response to selection in resistance and tolerance when selecting on resilience compared with direct selection on resistance and tolerance. Monte Carlo simulation was used combined with selection index theory to predict responses to selection. Using EBV for resilience in the absence of records for pathogen burden resulted in favorable responses in resistance and tolerance to infections, with higher responses in tolerance than in resistance. If resistance and tolerance were unfavorably correlated, lower selection responses were obtained, especially in resistance. When the genetic correlation was very unfavorable, the selection response in tolerance became negative. Results showed that lower selection responses in resistance and tolerance were obtained when the frequency of disease outbreaks was 10% rather than 50% of the contemporary groups. The efficiency of selection on EBV for resilience compared with selection on EBV for resistance and tolerance was, however, not affected by the frequency of disease outbreaks. When records on pathogen burden were available, selection responses in resistance, tolerance, and the total breeding goal were 3 to 28%, 66 to 398%, and 2 to 11% higher, respectively, than when using the EBV for resilience, showing a clear benefit of recording pathogen burden. This study shows that selection on resilience is a pragmatic way of increasing disease resistance and tolerance to infections in the absence of records on pathogen burden, but recording pathogen burden would yield higher selection responses in resistance and tolerance.

Validation of carcass lesions as indicators for on-farm health and welfare of pigs.

Abstract: Incorporating indicators for pig health and welfare at meat inspection could reduce the need for on-farm assessments. Skin and tail lesions are important welfare indicators in pigs with good potential to record during meat inspection and could possibly function as iceberg indicators of on farm welfare. The aim of this study was to validate the use of these carcass lesions at meat inspection for the assessment of pig health and welfare on farm. Thirty-one farrow-to-finish pig farms (∼12% of Irish herds) were assessed using an adapted version of the Welfare Quality protocol by inspecting 6 randomly selected pens of pigs in the first weaner (4 to 8 wk), second weaner (8 to 13 wk) and finisher stage (13 to 23 wk). The average prevalence of welfare outcomes for each stage was calculated. One batch of pigs was observed at slaughter and skin and tail lesions were scored according to severity for each carcass. The average prevalence of carcass lesion outcomes was calculated for each farm. Linear regression models were developed to predict the prevalence of each welfare outcome in each stage based on the prevalence of the different carcass lesions. The welfare outcomes of different welfare aspects that were best predicted by abattoir information (highest ) were poor body condition (first weaner stage), bursitis (second weaner stage), huddling (first weaner stage), severe tail lesions (finisher stage) and coughing (second weaner stage). Regression trees and receiver-operating curves (ROC) were used to evaluate the usefulness of carcass lesions as monitoring tools. Receiver-operating curves were created using the 75th percentile to classify farms as a problem farm for these welfare outcomes. Cut-off values of predictive carcass lesion prevalence were similar using both techniques. Models for predicting problem farms with poor body condition, bursitis and severe tail lesions were moderately accurate. Sensitivity and specificity ranged from 75 to 100% and 70 to 87%, respectively at the optimal cut-off value of the predictive carcass lesion prevalence. Results show potential for using carcass skin and tail lesions as iceberg indicators of pig health and welfare on farm. Future work is needed to evaluate the cost of including carcass lesion recording at meat inspection, the cost of failing to identify problem farms and the cost of incorrectly visiting or penalizing problem farms before carcass lesions can be used as welfare indicators in a commercial setting.

Analysis of the gut bacterial communities in beef cattle and their association with feed intake, growth, and efficiency.

Abstract: The impetus behind the global food security challenge is direct, with the necessity to feed almost 10 billion people by 2050. Developing a food-secure world, where people have access to a safe and sustainable food supply, is the principal goal of this challenge. To achieve this end, beef production enterprises must develop methods to produce more pounds of animal protein with less. Selection for feed-efficient beef cattle using genetic improvement technologies has helped to understand and improve the stayability and longevity of such traits within the herd. Yet genetic contributions to feed efficiency have been difficult to identify, and differing genetics, feed regimens, and environments among studies contribute to great variation and interpretation of results. With increasing evidence that hosts and their microbiomes interact in complex associations and networks, examining the gut microbial population variation in feed efficiency may lead to partially clarifying the considerable variation in the efficiency of feed utilization. The use of metagenomics and high-throughput sequencing has greatly impacted the study of the ruminant gut. The ability to interrogate these systems at great depth has permitted a greater understanding of the microbiological and molecular mechanisms involved in ruminant nutrition and health. Although the microbial communities of the reticulorumen have been well documented to date, our understanding of the populations within the gastrointestinal tract as a whole is limited. The composition and phylogenetic diversity of the gut microbial community are critical to the overall well-being of the host and must be determined to fully understand the relationship between the microbiomes within segments of the cattle gastrointestinal tract and feed efficiency, ADG, and ADFI. This review addresses recent research regarding the bacterial communities along the gastrointestinal tract of beef cattle; their association with ADG, ADFI, and feed efficiency; and the potential implications for beef production.

Integrated analysis of non-coding RNA and mRNA expression profiles of 2 pig breeds differing in muscle traits.

Abstract: Production of high-quality meat is important to satisfy the consumer and allow the pork industry to be competitive. It is evident that different muscle fiber types in different breeds greatly influence the pork quality, but the underlying molecular mechanism remains unclear. We used Ribo-Zero RNA-Seq and miRNA-Seq to examine global expressions of protein-coding transcripts and non-coding RNAs including miRNA, lncRNA, and circRNA in the longissimus dorsi of Landrace and Lantang pigs. Of the 22,469 identified coding transcripts, only 547 candidates were differentially expressed, including 461 upregulated and 86 downregulated transcripts in the Lantang pigs compared with Landrace. Gene ontology analysis of these differentially-expressed transcripts further revealed 17 genes involved in myogenesis. In addition, 5,566 lncRNA and 4,360 circRNA candidates were found to be differentially expressed. Of these, 3,976 lncRNAs and 1,401 circRNAs were upregulated in the Lantang library, while 1,590 lncRNAs and 2,959 circRNAs were downregulated. Of the differentially expressed circRNAs, 236 candidates were edited from 93 functional hosting-genes related to myogenesis. We found 96 showed upregulation and 140 showed downregulation. By analyzing Ribo-Zero RNA-Seq data in combination with matched miRNA profiles, we identified 68 sponge modulators participating in 26 miRNA-mediated ceRNA interactions, including 19 lncRNAs, 40 circRNAs, and 9 mRNAs. Our study uncovered a novel post-transcriptional regulation layer which could help in the understanding of the mechanisms that underlie porcine myofiber development in different breeds.

Influence of lignocellulose and low or high levels of sugar beet pulp on nutrient digestibility and the fecal microbiota in dogs

Abstract: Lignocellulose is an alternative fiber source for dogs; however, it has not yet been studied as a feed ingredient for the nutrition of dogs. Eight adult Beagles were involved in the study, which consisted of 3 feeding periods of 8 to 12 wk each. All dogs received 3 different diets, which either had the same concentration of fiber sources (2.7% sugar beet pulp or lignocellulose) or were formulated for a similar concentration of approximately 3% crude fiber: 12% sugar beet pulp (highSBP; 3.1% crude fiber), 2.7% sugar beet pulp (lowSBP; 0.96% crude fiber), or 2.7% lignocellulose (LC; 2.4% crude fiber). Feces samples were collected at the end of each feeding period, and the apparent nutrient digestibility, daily amount, and DM content of feces and fecal cell numbers of relevant bacteria were analyzed. The daily feces amount was lower and the feces DM was higher when dogs were fed the LC diet and the lowSBP diet compared with the highSBP diet ( < 0.001). Apparent digestibility of CP, Na, and K was highest with the lowSBP diet followed by the LC and highSBP diets ( < 0.001). After feeding LC, the bacterial cell counts of spp., spp., and the cluster were reduced compared with feeding highSBP and even more reduced after feeding lowSBP ( < 0.001). The bacterial cell count of the cluster was lower in LC and lowSBP compared with highSBP ( < 0.001). The feces of dogs fed LC and lowSBP had lower concentrations of acetate ( < 0.001), propionate ( < 0.001), -butyrate ( = 0.015), total fatty acids ( < 0.001), and lactate ( < 0.001) compared with dogs fed highSBP. The concentration of -butyrate was higher in the feces of dogs fed with LC compared with dogs fed high and low sugar beet pulp (SBP; < 0.001). The pH of the feces of the LC-fed dogs was highest followed by lowSBP- and highSBP-fed dogs ( < 0.001). Depending on the concentration, the use of LC and SBP as fiber sources in dog feed has different impacts on the fecal microbiota and the apparent digestibility of nutrients. Therefore, different areas of application should be considered.

Dietary supplement rich in fiber fed to late gestating sows during transition reduces rate of stillborn piglets

Abstract: The beneficial effects of dietary fiber (DF) from a behavioral and welfare perspective have been thoroughly studied. However, data on the effects of DF on reproductive performance are scarce. Therefore, the aim of this study was to investigate the impact of increased DF supply during the last 2 wk of gestation on stillbirth rate, preweaning mortality, and total piglet mortality. A total of 644 sows were selected for the experiment from a commercial farm, and the sows were inseminated in weekly batches. Sows in the control group ( = 310) were fed according to the normal feeding strategy of the farm with a gestation diet until 1 wk before expected farrowing, then a transition diet until d 5 of lactation, and then a lactation diet until weaning. Sows in the treatment group ( = 334) were fed as the control group except that 280 g/d of the gestation diet (from d 102 to 108 of gestation) and 570 g/d of the transition diet (from d 109 of gestation until farrowing) was daily replaced with 350 and 700 g/d, respectively, of a DF-rich supplement. Both groups received isocaloric diets on a NE basis. The numbers of live-born and stillborn piglets as well as mortality of live-born piglets with presumed causes of death were recorded. The supplemented DF reduced the proportion of stillborn piglets from 8.8 to 6.6% ( < 0.001) and mortality of total born piglets from 22.3 to 19.9% ( = 0.004) but had no impact on preweaning mortality of the piglets ( = 0.21). Moreover, supplemented DF reduced the proportion of death due to poor viability ( < 0.001; 2.8 vs. 1.5% in the control and treatment groups, respectively) and prevalence of piglet diarrhea ( = 0.004; 0.7 vs. 0.3% in the control and treatment groups, respectively). Crushing, low birth weight, and poor viability were the top 3 contributors to preweaning mortality of live-born piglets, in descending order. In conclusion, the supplemented DF reduced the proportion of stillborn piglets and total piglet mortality as well as mortality due to poor viability and piglet diarrhea in lactation.

BOARD INVITED REVIEW: The purebred-crossbred correlation in pigs: A review of theory, estimates, and implications.

Abstract: Pig and poultry production relies on crossbreeding of purebred populations to produce production animals. In those breeding schemes, selection takes place within the purebred population to improve crossbred performance (CB performance). The genetic correlation between purebred performance (PB performance) and CB performance () is, however, lower than unity for many traits. When is low, the use of CB performance in selection is required to achieve sizable genetic progress. The objectives of this paper were to describe the different components and importance of , and to review existing literature that report estimates in pigs. The has 3 components: 1) genotype by genotype interactions, 2) genotype by environment interactions, and 3) differences in trait measurements. We theoretically showed that direct selection for CB performance reduces the response to selection in purebreds for.

Dietary supplementation with arginine and glutamic acid modifies growth performance, carcass traits, and meat quality in growing-finishing pigs.

Abstract: Sixty Duroc × Large White × Landrace pigs with an average initial BW of 771 ± 13 kg were used to investigate the effects of dietary supplementation with arginine and glutamic acid on growth performance, carcass traits, and meat quality in growing-finishing pigs The animals were randomly assigned to 1 of 5 treatment groups (12 pigs/group, male:female ratio 1:1) The pigs in the control group were fed a basal diet (basal diet group), and those in the experimental groups were fed the basal diet supplemented with 205% -alanine (isonitrogenous group), 10% -arginine (Arg group), 1% glutamic acid + 144% -alanine (Glu group), or 10% -arginine + 10% glutamic acid (Arg+Glu group) After a 60-d period of supplementation, growth performance, carcass traits, and meat quality were evaluated The results showed no significant differences ( > 005) in growth performance and carcass traits of the pigs in the Arg group relative to the basal diet group; however, the longissimus dorsi (LD) muscle and back fat showed a decrease ( 005) on the final BW, phase 2 ADFI, and average daily weight gain in pigs but decreased ( < 005) their phase 1 ADFI, average back fat thickness, and percentage of SFA in the LD muscle and back fat, and increased ( < 005) the im fat (IMF) content of the LD and biceps femoris muscles when compared with the basal diet group Furthermore, a 16% decrease in yellowness (b* value; < 005) was observed in the Arg+Glu group pigs when compared with the isonitrogenous group These findings suggest that dietary supplementation with both Arg and Glu beneficially increases the IMF deposition and improves the meat color and fatty acid composition without affecting growth performance and sc fat in pigs, providing a novel strategy to enhance meat quality in growing-finishing pigs

Best management practices for newly weaned calves for improved health and well-being.

Abstract: Morbidity and mortality in newly weaned calves resulting from bovine respiratory disease (BRD) continue to be the most significant problems facing the beef industry. Morbidity attributed to BRD accounts for approximately 75% of total feedlot morbidity. Several experiments have documented the economic impacts of BRD. Direct costs attributable to BRD include death loss, treatment and labor costs, and prevention costs, while indirect costs associated with BRD include decreased growth performance and feed efficiency, increased days on feed, and decreased carcass merit and market value. In recent years, cattle treated for BRD have returned $50 to $250 less per head at harvest than cattle never treated for BRD. Best management practices for newly weaned calves vary depending on a multitude of factors including: season of year calves are purchased, calf genetics, length of time in the marketing and transport channels, previous management and vaccination programs, and other factors. In general, calves purchased directly from a ranch have fewer health problems than calves purchased through auction markets. The longer a calf is in the marketing chain, the more likely health problems will be encountered. Calves that have spent several days in the marketing chain may develop clinical BRD before or very soon after arrival, whereas cattle with less time in the marketing chain may get sick later (2 to 4 wk), due to the length of time it takes for BRD to develop. On or before arrival, calves should be given a risk score (high, medium, or low) that relates to the quantity and magnitude of stress they have encountered and the probability they will develop BRD. High-risk calves typically will have been recently weaned, received no vaccinations, not been castrated or dehorned, been commingled, and moved through an auction market. Low-risk calves will often originate from a single source and will have gone through a preconditioning program that includes vaccination, castration, dehorning, weaning, and potentially feed bunk adaptation. Variation exists within risk category, so the preliminary assessment should be combined with visual observation on arrival as additional health assessments and feed intake information becomes available. Cattle managers should adjust management strategies based on risk category to meet the perceived needs of individual lots of cattle to improve the health and well-being of newly weaned calves.

A mixed treatment comparison meta-analysis of metaphylaxis treatments for bovine respiratory disease in beef cattle.

Abstract: Citation: Abell, K. M., Theurer, M. E., Larson, R. L., White, B. J., & Apley, M. (2017). A mixed treatment comparison meta-analysis of metaphylaxis treatments for bovine respiratory disease in beef cattle. Journal of Animal Science, 95(2), 626-635. doi:10.2527/jas2016.1062

Estimating glucose requirements of an activated immune system in growing pigs.

Abstract: Activated immune cells become obligate glucose utilizers, and a large i.v. lipopolysaccharide (LPS) dose causes insulin resistance and severe hypoglycemia. Therefore, study objectives were to quantify the amount of glucose needed to maintain euglycemia following an endotoxin challenge as a proxy of leukocyte glucose requirements. Fifteen fasted crossbred gilts (30.3 ± 1.7 kg) were bilaterally jugular catheterized and assigned 1 of 2 i.v. bolus treatments: control (CON; 10 mL sterile saline; = 7) or LPS challenge + euglycemic clamp (LPS-Eu; 055:B5; 5 μg/kg BW; 50% dextrose infusion to maintain euglycemia; = 8). Following administration, blood glucose was determined every 10 min and dextrose infusion rates were adjusted in LPS-Eu pigs to maintain euglycemia for 8 h. Pigs were fasted for 8 h prior to the bolus and remained fasted throughout the challenge. Rectal temperature was increased in LPS-Eu pigs relative to CON pigs (39.8 vs. 38.8°C; < 0.01). Relative to the baseline, CON pigs had 20% decreased blood glucose from 300 to 480 min postbolus ( = 0.01) whereas circulating glucose content in LPS-Eu pigs did not differ ( = 0.96) from prebolus levels. A total of 116 ± 8 g of infused glucose was required to maintain euglycemia in LPS-Eu pigs. Relative to CON pigs, overall plasma insulin, blood urea nitrogen, β-hydroxybutrate, lactate, and LPS-binding protein were increased in LPS-Eu pigs (295, 108, 29, 133, and 13%, respectively; ≤ 0.04) whereas NEFA was decreased (66%; < 0.01). Neutrophils in LPS-Eu pigs were decreased 84% at 120 min postbolus and returned to CON levels by 480 min ( < 0.01). Overall, lymphocytes, monocytes, eosinophils, and basophils were decreased in LPS-Eu pigs relative to CON pigs (75, 87, 70, and 50%, respectively; ≤ 0.05). These alterations in metabolism and the large amount of glucose needed to maintain euglycemia indicate nutrient repartitioning away from growth toward the immune system. Glucose is an important fuel for the immune system, and data from this study established that the glucose requirements of an intensely and acutely activated immune system in growing pigs are approximately 1.1 g/kg BW/h.

Effects of temperament on physiological, productive, and reproductive responses in Bos indicus beef cows

Abstract: This experiment evaluated the effects of temperament on physiological, productive, and reproductive responses in Bos indicus beef cows. A total of 953 lactating, multiparous, non-pregnant Nelore cows (age = 99 ± 2 mo; days post-partum = 51.4 ± 0.3 d; BCS = 5.34 ± 0.04; BW = 430 ± 2 kg) were allocated into 8 groups of approximately 120 cows each. Groups were assigned to an estrus synchronization + timedAI protocol at the beginning of the breeding season. Concurrently with AI, blood samples were collected, hair samples were clipped from the tail switch, and cow temperament was evaluated via chute score and exit velocity. Individual exit score was calculated within each group by dividing exit velocity into quintiles and assigning cows with a score from 1 to 5 (1 = slowest; 5 = fastest cow). Temperament scores were calculated by averaging cow chute score and exit score, and used to define cow temperament ( ≤ 3 = adequate, n = 726; ADQ; > 3 = excitable, n = 227; EXC). Cows not pregnant to AI were assigned to a second timed-AI protocol (n = 184 ADQ and 72 EXC) or exposed (n = 269 ADQ and 90 EXC) to bulls for 60 d. Pregnancy status was verified 30 d after each AI and 45 d after the breeding season via transrectal ultrasound. Cow age, BW, BCS, and d post-partum at the beginning of the breeding season were similar (P ≥ 0.27) between ADQ and EXC cows. At first timed-AI, EXC had greater (P < 0.01) serum cortisol but similar (P ≥ 0.87) serum haptoglobin and hair cortisol concentrations compared with ADQ cows (49.1 vs. 39.1 ng/mL of serum cortisol, SEM = 1.0). Pregnancy rate to first timed-AI tended (P = 0.09) to be less in EXC vs. ADQ cows (41.0 vs. 47.3%; SEM = 3.6), whereas no treatment differences were detected (P ≥ 0.23) for subsequent pregnancy outcomes. Calving rate was less (P = 0.04) in EXC vs. ADQ cows (68.3 vs. 74.8%; SEM = 2.2), which can be attributed to the greater (P = 0.05) pregnancy loss detected in EXC cows (9.9 vs. 5.9%; SEM = 1.4). Weaning rate tended (P = 0.09) to be less, whereas calf weaning BW and age were less (P ≤ 0.05) in EXC vs. ADQ cows (63.9 vs. 69.4%, SEM = 2.4; 209 vs. 212 d, SEM = 1; 204 vs. 210 kg, SEM = 2). Hence, kg of calf weaned/cow exposed to breeding was reduced (P = 0.04) in EXC vs. ADQ cows (130 vs. 146 kg, SEM = 5). In summary, B. indicus cows with excitable temperament had reduced reproductive performance and overall productivity compared to cohorts with adequate temperament when exposed to timed-AI + natural breeding.

BREEDING AND GENETICS SYMPOSIUM: Breeding for resilience to heat stress effects in dairy ruminants. A comprehensive review.

Abstract: Selection for heat tolerant (HT) animals in dairy production has been so far linked to estimation of declines in production using milk recording and meteorological information on the day of control using reaction norms. Results from these models show that there is a reasonable amount of genetic variability in the individual response to high heat loads, which makes feasible selection of HT animals at low costs. However, the antagonistic relationship between level of production and response to heat stress (HS) implies that selection for HT animals under this approach must be done with caution so that productivity is not damaged. Decomposition of the genetic variability in principal components (PC) can provide selection criteria independent of milk production level although biological interpretation of PC is difficult. Moreover, given that response to heat stress for each animal is estimated with very sparse information collected under different physiological and management circumstances, biased (normally underestimation) and lack of accuracy may be expected. Alternative phenotypic characterization of HT can come from the use of physiological traits, which have also shown moderate heritability. However, costs of a large scale implementation based on physiological characteristics has precluded its use. Another alternative is the use of biomarkers that define heat tolerance. A review of biomarkers of HS from more recent studies is provided. Of particular interest are milk biomarkers, which together with infrared spectra prediction equations can provide useful tools for genetic selection. In the 'omics' era, genomics, transcriptomics, proteomics and metabolomics have been already used to detect genes affecting HT. A review of findings in these areas is also provided. Except for the slick hair gene, there are no other genes for which variants have been clearly associated with HT. However, integration of omics information could help in pointing at knots of the HS control network and, in the end, to a panel of markers to be used in the selection of HT animals. Overall, HT is a complex phenomenon that requires integration of fine phenotypes and omics information to provide accurate tools for selection without damaging productivity. Technological developments to make on-farm implementation feasible and with greater insight into the key biomarkers and genes involved in HT are needed.

Prevalence of multi drug antimicrobial resistance in isolated from high-risk stocker cattle at arrival and two weeks after processing.

Abstract: Bovine respiratory disease (BRD) is the leading cause of morbidity and mortality in North American beef cattle. () is the bacterial pathogen most frequently isolated from cattle with BRD and the prevalence of antimicrobial resistance in this pathogen has been increasing. Administration of antimicrobials to prevent BRD is commonplace in stocker cattle, but the impact of this practice on emergence of resistance in is unknown. High risk, sale barn origin bull and steer calves ( = 169) were transported to a stocker facility in central Georgia and sampled via deep nasopharyngeal swab (NPS) at arrival processing. All calves received the macrolide antimicrobial tulathromycin (2.5 mg/kg subcutaneously) at arrival processing. A second NPS was collected from each calf 10 to 14 d after arrival. The occasional calves diagnosed and treated for BRD prior to 10 to 14 d were swabbed and cultured prior to treatment. Swabs were submitted for culture and antimicrobial susceptibility testing using the Kirby-Bauer disk diffusion method. Of the 169 cattle enrolled, 27 (16.0%) were culture positive for at arrival processing and of these, a multi-drug resistant (MDR) strain of was detected in 1 (3.7%). In contrast, 123 (72.8%) cattle were culture positive for at second sampling and of these, a MDR strain of was detected in 122 (99.2%). The proportions of cattle culture positive for and positive for MDR at arrival processing and at second sampling were significantly different ( < 0.001). At the level of the individual bacterial isolate, 366 individual isolates were collected from the calves at the time of the second sampling. Of these isolates, 361 (98.6%) were intermediate or resistant to all macrolides tested (tilmicosin, gamithromycin, tulathromycin) and the fluoroquinolone enrofloxacin. In addition, 254 isolates (69.4%) were intermediate or resistant to florfenicol and 4 (1.1%) were intermediate or resistant to ceftiofur. There was a significant difference in the proportion of isolates resistant to all of the drug classes except cephalosporins at arrival processing versus second sampling ( < 0.001). Our results show that there was an increase in the proportion of calves positive for from arrival processing to second sampling, and that there was an increase in the proportion of calves that had MDR strains of detected from arrival processing to second sampling. More research is needed to understand the role of metaphylaxis on MDR in and the impact of MDR on morbidity and mortality in stocker cattle.

Automated collection of heat stress data in livestock: new technologies and opportunities.

Abstract: © The Author(s) 2018. Published by Oxford University Press on behalf of the American Society of Animal Science. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com Transl. Anim. Sci. 2018.2:319–323 doi: 10.1093/tas/txy061

Technical note: Genomic evaluation for crossbred performance in a single-step approach with metafounders.

Abstract: A single-step genomic BLUP method (ssGBLUP) has been successfully developed and applied for purebred and crossbred performance in pigs. However, it requires phasing the genotypes and inferring the breed origin of alleles in crossbred animals, which is somewhat inconvenient. Recently, a new concept of metafounders that considers the relationship within and across base populations was developed. With this concept of metafounders, regular methods to build and invert the pedigree relationships matrix can be used with only minor modifications and, moreover, genomic relationships and pedigree-based relationships are automatically compatible in the ssGBLUP. In this study, data for the total number of piglets born in Danish Landrace, Yorkshire, and 2-way crossbred pigs and models for purebred and crossbred performance were revisited by use of ssGBLUP with 2 metafounders. Genetic variances and genetic correlations between purebred and crossbred performances were first reestimated. Then, model-based reliabilities of purebred boars for their crossbred performance and predictive abilities for crossbred animals were compared in different scenarios. Results in this study were compared to those in a previous study with identical data but with models that required known breed origin of crossbred genotypes. Results show that relationships for base individuals within Landrace and within Yorkshire are similar and that the ancestor populations for Landrace and Yorkshire are related. In terms of model-based reliabilities and predictive abilities, ssGBLUP with metafounders performs at least as well as the single-step method requiring phasing at a lower complexity.

Heritability of methane emissions from dairy cows over a lactation measured on commercial farms

Abstract: Methane emission is currently an important trait in studies on ruminants due to its environmental and economic impact. Recent studies were based on short-time measurements on individual cows. As methane emission is a longitudinal trait, it is important to investigate its changes over a full lactation. In this study, we aimed to estimate the heritability of the estimated methane emissions from dairy cows using Fourier-transform infrared spectroscopy during milking in an automated milking system by implementing the random regression method. The methane measurements were taken on 485 Polish Holstein-Friesian cows at 2 commercial farms located in western Poland. The overall daily estimated methane emission was 279 g/d. Genetic variance fluctuated over the course of lactation around the average level of 1,509 (g/d), with the highest level, 1,866 (g/d), at the end of the lactation. The permanent environment variance values started at 2,865 (g/d) and then dropped to around 846 (g/d) at 100 d in milk (DIM) to reach the level of 2,444 (g/d) at the end of lactation. The residual variance was estimated at 2,620 (g/d). The average repeatability was 0.25. The heritability level fluctuated over the course of lactation, starting at 0.23 (SE 0.12) and then increasing to its maximum value of 0.3 (SE 0.08) at 212 DIM and ending at the level of 0.27 (SE 0.12). Average heritability was 0.27 (average SE 0.09). We have shown that estimated methane emission is a heritable trait and that the heritability level changes over the course of lactation. The observed changes and low genetic correlations between distant DIM suggest that it may be important to consider the period in which methane phenotypes are collected.

Enteric methane emissions from low- and high-residual feed intake beef heifers measured using GreenFeed and respiration chamber techniques.

Abstract: The objectives of this study were to evaluate the relationship between residual feed intake (RFI; g/d) and enteric methane (CH) production (g/kg DM) and to compare CH and carbon dioxide (CO) emissions measured using respiration chambers (RC) and the GreenFeed emission monitoring (GEM) system (C-Lock Inc., Rapid City, SD). A total of 98 crossbred replacement heifers were group housed in 2 pens and fed barley silage ad libitum and their individual feed intakes were recorded by 16 automated feeding bunks (GrowSafe, Airdrie, AB, Canada) for a period of 72 d to determine their phenotypic RFI. Heifers were ranked on the basis of phenotypic RFI, and 16 heifers (8 with low RFI and 8 with high RFI) were randomly selected for enteric CH and CO emissions measurement. Enteric CH and CO emissions of individual animals were measured over two 25-d periods using RC (2 d/period) and GEM systems (all days when not in chambers). During gas measurements metabolic BW tended to be greater ( ≤ 0.09) for high-RFI heifers but ADG tended ( = 0.09) to be greater for low-RFI heifers. As expected, high-RFI heifers consumed 6.9% more feed ( = 0.03) compared to their more efficient counterparts (7.1 vs. 6.6 kg DM/d). Average CH emissions were 202 and 222 g/d ( = 0.02) with the GEM system and 156 and 164 g/d ( = 0.40) with RC for the low- and high-RFI heifers, respectively. When adjusted for feed intake, CH yield (g/kg DMI) was similar for high- and low-RFI heifers (GEM: 27.7 and 28.5, = 0.25; RC: 26.5 and 26.5, = 0.99). However, CH yield differed between the 2 measurement techniques only for the high-RFI group ( = 0.01). Estimates of CO yield (g/kg DMI) also differed between the 2 techniques ( ≤ 0.03). Our study found that high- and low-efficiency cattle produce similar CH yield but different daily CH emissions. The 2 measurement techniques differ in estimating CH and CO emissions, partially because of differences in conditions (lower feed intakes of cattle while in chambers, fewer days measured in chambers) during measurement. We conclude that when intake of animals is known, the GEM system offers a robust and accurate means of estimating CH emissions from animals under field conditions.

Nutrient digestibility and milk production responses to increasing levels of palmitic acid supplementation vary in cows receiving diets with or without whole cottonseed.

Abstract: Our study evaluated the dose-dependent effects of a palmitic acid-enriched supplement in basal diets with or without the inclusion of whole cottonseed on nutrient digestibility and production responses of dairy cows. Sixteen Holstein cows (149 ± 56 days in milk) were used in a split plot Latin square design experiment. Cows were blocked by 3.5% fat-corrected milk (FCM) and allocated to a main plot receiving either a basal diet with soyhulls (SH, = 8) or a basal diet with whole cottonseed (CS, = 8) that was fed throughout the experiment. A palmitic acid-enriched supplement (PA 88.5% C16:0) was fed at 0, 0.75, 1.50, or 2.25% of ration DM in a replicated 4 × 4 Latin Square design within each basal diet group. Periods were 14 d with the final 4 d used for data collection. PA dose increased milk fat content linearly, and cubically affected yields of milk fat and 3.5% FCM. The PA dose did not affect milk protein and lactose contents, BW, and BCS, but tended to increase yields of milk, milk protein, and milk lactose. Also, PA dose reduced DMI and 16-carbon fatty acid digestibility quadratically, and increased 18-carbon fatty acid digestibility quadratically. There were no effects of basal diet on the yield of milk or milk components, but DMI tended to decrease in CS compared with SH, increasing feed efficiency (3.5% FCM/DMI). Compared with SH, CS diets increased yield of preformed milk fatty acids and 16-carbon fatty acid digestibility, and tended to decrease 18-carbon fatty acid digestibility. We observed basal diet × PA dose interactions for yields of milk and milk protein and for 16-carbon and total fatty acid digestibility, as well as tendency for yields of milk fat and 3.5% FCM. Also, there was a tendency for an interaction between basal diet and PA dose for NDF digestibility, which increased more for CS with increasing PA than for SH. PA dose linearly decreased digestibility of total fatty acids in SH diets but did not affect it in CS diets Results demonstrate that responses to PA dose are affected by the dietary basal diet. Additionally, the decrease in fatty acid digestibility only in the SH diets suggests that digestibility is impacted mainly by the profile of 16- and 18-carbon fatty acids reaching the duodenum. Under the dietary conditions evaluated, the yield of 3.5% FCM and milk fat were optimal when PA was fed at 1.5% of ration DM.

What is good for small piglets might not be good for big piglets: The consequences of cross-fostering and creep feed provision on performance to slaughter,

Abstract: Major improvements in sow prolificacy have resulted in larger litters but, at the same time, increased the proportion of piglets born light weight. Different management strategies aim to enhance the performance of, and limit light-weight piglet contribution to, BW variation within a batch; however, consequences on heavy-weight littermates are often neglected. This study investigated the effects of different litter compositions, created through cross-fostering, and the provision of creep feed on preweaning behavior and short- and long-term performance of piglets born either light weight (≤1.25 kg) or heavy weight (1.50-2.00 kg). Piglets were cross-fostered at birth to create litters with only similar-sized piglets (light weight or heavy weight; UNIFORM litters) and litters with equal numbers of light-weight and heavy-weight piglets (MIXED litters); half of the litters were offered creep feed and the remaining were not. Piglet behavior during a suckling bout and at the creep feeder was assessed; a green dye was used to discern between consumers and nonconsumers of creep feed. The interaction between litter composition and birth weight (BiW) class influenced piglet BW at weaning ( 0.05) for either BiW class. However, litter composition significantly affected daily creep feed consumption ( = 0.046) and fecal color ( = 0.022), with heavy-weight piglets in UNIFORM litters consuming the highest amount of creep feed and having the greenest feces. In addition, a lower number of heavy-weight piglets in UNIFORM litters were classified as nonconsumers ( = 0.002). The weight advantage heavy-weight and light-weight piglets had at weaning when reared in MIXED and UNIFORM litters, respectively, was sustained throughout the productive period. In conclusion, reducing BW variation within litter (UNIFORM litters) was beneficial for piglets born light weight but not for piglets born heavy weight; the latter were disadvantaged up to slaughter. Although heavy-weight piglets in UNIFORM litters consumed the greatest amount of creep feed, this was not able to overcome their growth disadvantage compared with heavy-weight piglets in MIXED litters.

Effects of grass silage quality and level of feed intake on enteric methane production in lactating dairy cows

Abstract: The objective of this study was to determine the effect of level of feed intake and quality of ryegrass silage as well as their interaction on enteric methane (CH4) emission from dairy cows. In a randomized block design, 56 lactating dairy cows received a diet of grass silage, corn silage, and a compound feed meal (70:10:20 on DM basis). Treatments consisted of 4 grass silage qualities prepared from grass harvested from leafy through late heading stage, and offered to dairy cows at 96 ± 2.4 (mean ± SEM) days in milk (namely, high intake) and 217 ± 2.4 d in milk (namely, low intake). Grass silage CP content varied between 124 and 286 g/kg of DM, and NDF content between 365 and 546 g/kg of DM. After 12 d of adaptation, enteric CH4 production of cows was measured in open-circuit climate-controlled respiration chambers for 5 d. No interaction between DMI and grass quality on CH4 emission, or on milk production, diet digestibility, and energy, and N retention was found (P ≥ 0.17). Cows had a greater DMI (16.6 vs. 15.5 kg/d; SEM 0.46) and greater fat- and protein-corrected milk (FPCM) yield (29.9 vs. 25.4 kg/d; SEM 1.24) at high than low intake (both P ≤ 0.001). Apparent total-tract nutrient digestibility was not affected (P ≥ 0.08) by DMI level. Total enteric CH4 production (346 ± 10.9 g/d) was not affected (P = 0.15) by DMI level. A small, significant (P = 0.025) decrease at high compared with low intake occurred for CH4 yield (21.8 ± 0.59 g/kg of DMI; −4%). Methane emission intensity (12.8 ± 0.56 g/kg of FPCM; −12%) was considerably smaller (P ≤ 0.001) at high intake as a result of greater milk yields realized in early lactation. As grass quality decreased from leafy through late heading stage, FPCM yield and apparent total-tract OM digestibility declined (−12%; P ≤ 0.015), whereas total CH4 production (+13%), CH4 yield (+21%), and CH4 emission intensity (+28%) increased (P ≤ 0.001). Our results suggest that improving grass silage quality by cutting grass at an earlier stage considerably reduces enteric CH4 emissions from dairy cows, independent of DMI. In contrast, losses of N in manure increased for the earlier cut grass silage treatments. The small increase in DMI at high intake was associated with a small to moderate reduction in CH4 emission per unit of DMI and GE intake. This study confirmed that enteric CH4 emissions from dairy cows at distinct levels of feed intake depend on the nutritive value and chemical composition of the grass silage.

National Beef Quality Audit–2016: In-plant survey of carcass characteristics related to quality, quantity, and value of fed steers and heifers

Abstract: The National Beef Quality Audit (NBQA)-2016 used in-plant cooler assessments to benchmark the current status of the fed steer and heifer beef industry in the United States. In-plant cooler assessments ( = 9,106 carcasses) were conducted at 30 facilities, where approximately 10% of a single day's production were evaluated for USDA quality grade (QG) and yield grade (YG) factors. Frequencies of evaluated traits were 66.5% steer and 33.4% heifer sex classes and 82.9% native, 15.9% dairy-type, and 1.2% estimated breed types. Mean USDA YG factors were 1.42 cm for adjusted fat thickness, 89.5 cm for LM area, 390.3 kg for HCW, and 1.9% for KPH. Mean USDA YG was 3.1, with a frequency distribution of 9.6% YG 1, 36.7% YG 2, 39.2% YG 3, 12.0% YG 4, and 2.5% YG 5. Mean USDA QG traits were Small for marbling score, A for overall maturity, A55 for lean maturity, and A for skeletal maturity. Mean USDA QG was Select with a frequency distribution of QG of 3.8% Prime, 67.3% Choice, 23.2% Select, and 5.6% lower score. Lower score included dark cutter (1.9%), blood splash (0.1%), and hard bone, which are USDA overall maturity scores of C or older (1.8%). Marbling score distributions were 0.85% Slightly Abundant or greater, 7.63% Moderate, 23.54% Modest, 39.63% Small, 23.62% Slight, and 0.83% Traces or less. Carcasses that were Choice or Select and USDA YG 2 or 3 accounted for 70.7% of the carcasses evaluated. Compared with the previous NBQA, we found a numerical increase in mean USDA YG, USDA QG, adjusted fat thickness, HCW, LM area, and marbling score with an increase in dairy-type carcasses and percentage of carcasses grading USDA Prime and Choice as well as frequency of USDA YG 4 and 5. The findings from this study will be used by all segments of the industry to understand and improve the quality of fed steer and heifer beef that is being produced.