Search

Liver abscesses pose a significant economic burden on the beef industry, resulting in substantial profit losses. A contributor to these losses is the decreased productivity and feed efficiency observed in affected cattle. Reduced feed efficiency could be attributed to the impairment of metabolic activity due to liver tissue damage caused by the abscesses. While tissue within the abscess itself is dysfunctional, little is known about the functional state of the surrounding liver tissue. Considering this, the present research aimed to evaluate liver tissue gene expression profiles at varying distances from liver abscesses. Tissue samples (n = 21) were collected from three distinct regions: 1) <4 mm proximal from the abscess without including abscessed tissue (adjacent tissue), 2) 3 cm proximal from the abscess (nearby tissue), and 3) from livers with no abscesses (healthy controls). Gene expression comparisons utilizing DESeq were conducted between each tissue sample group. The number of differentially expressed genes (FDR ≤ 0.10) identified in each comparison is presented in Table 1. Tissue directly adjacent to the liver abscess was substantially different in gene expression when compared with both the healthy and tissue 3 cm proximal to an abscess. Fewer genes exhibited differential expression between healthy tissue and tissue taken 3 cm away. Gene enrichment analysis was conducted using the KOBAS-i software to identify biological pathways associated with the differentially expressed genes. Genes upregulated in liver tissue adjacent to the abscess were associated (FDR ≤ 0.10) with immune response pathways, including the “T cell receptor signaling pathway” and “Cytokine-Cytokine receptor interaction,” whereas downregulated genes were linked to metabolic pathways such as “Fatty Acid Metabolism” and multiple amino acid biosynthesis pathways. Gene expression differences between tissue 3 cm away and healthy tissue were minimal; however, enrichment analysis identified significant (FDR ≤ 0.10) metabolic pathways such as the “peroxisome proliferator-activated receptor signaling” which is involved in gluconeogenesis and lipid metabolism, suggesting some metabolic alterations up to 3 cm proximal from the abscess. Upregulation of immune response pathways and downregulation of metabolic pathways in the adjacent tissue suggest a shift in cellular priorities, diverting resources to combat the active infection rather than routine metabolic processes. This localized immune response and metabolic dysregulation observed in the liver tissue adjacent to the abscess, coupled with metabolic alterations up to 3 cm away, highlight the effects of liver abscesses on the overall metabolic capacity and functionality of the liver. Continued research should focus on investigating the effect of abscess severity on overall liver function. [ABSTRACT FROM AUTHOR]

Liver abscesses (LA) continue to be an economic challenge for the beef industry. Chronic ruminal acidosis and ruminitis contribute to LA development. Fusobacterium necrophorum subsp. necrophorum, a ruminal bacterium, is the primary causative agent. Damaged ruminal, and possibly other gut regions, become susceptible to invasion and colonization by subsp. necrophorum, which reaches the liver via portal blood to cause abscesses. We hypothesize that the LA occurrence is related to the presence and concentrations of subsp. necrophorum in gut contents and epithelial tissues. Our primary objective was to detect, isolate and quantify subsp. necrophorum in gut contents and tissues in steers with experimentally induced LA. An experimental model, which included ruminal acidosis followed by intraruminal inoculation of subsp. necrophorum alone or with Salmonella enterica serotype Lubbock, was used to assess the relationship. Steers (n = 61) from three independent studies with three treatment groups were used. Treatments included: 1) forage-based diet with intraruminal inoculation of subsp. necrophorum; 2) ruminal acidosis with intraruminal inoculation of subsp. necrophorum; and 3) ruminal acidosis with intraruminal inoculation of subsp. necrophorum and S. Lubbock. Steers were euthanized 3 wk after bacterial inoculation and liver, gut contents, and tissue samples (ruminal, ileal and colonic) from steers with LA (n = 27) and with healthy livers (n = 34) were collected and subjected to culture method and quantitative PCR to isolate, detect, and quantify subsp. necrophorum. Data were analyzed by PROC GLIMMIX of SAS after summarizing frequency of isolation in various sample types within each study for steers with and without LA and converted to a binomial proportion. Concentrations were analyzed using steer as the experimental unit. The model included the fixed effect of liver status (abscessed or not) and study as the random effect. The frequency of isolation and mean concentration of subsp. necrophorum in purulent materials of LA were 100% and 3.5 x 107 Log10 CFU/g, respectively. The frequency of isolation of subsp. necrophorum from ruminal tissues of steers with LA was greater than steers with healthy livers (35.4 vs 14.5%; P = 0.04). Likewise, the concentration of subsp. necrophorum in ruminal tissues was greater in steers with LA than with healthy livers (4.2 vs 3.6 Log10 CFU/g; P < 0.001). None of the ileal and colonic tissues, except one ileal tissue in each group, yielded subsp. necrophorum. The concentrations of subsp. necrophorum in ruminal, ileal, and colonic contents did not differ (P = 0.9) between steers with LA or with healthy livers. Our data suggest that the occurrence of LA is positively related to prevalence and concentration of subsp. necrophorum in ruminal tissue, and the colonization likely serves as a source of continuous flow of bacterial emboli into the portal blood to initiate LA development. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine if ultrasound estimates of carcass quality traits could predict the final quality factors that influence purchases of consumers. Beefmaster steers (n = 86) representing two different sires were ultrasounded 48 d and 73 d before harvest using an Aloka 500 ultrasound unit, equipped with a 17.2cm probe to collect 12th rib fat thickness (BFU), 12th rib longissimus muscle area (LMAU), intramuscular fat (%FATU) and rump fat (RFU). International Livestock Image Analysis (I.L.I.A) software (Harrison, Arkansas) was used for processing images to determine BFU, LMAU, %FATU and RFU using chute side captured ultrasound images on all steers. An Ultrasound Guidelines Council (UGC) field and lab certified technician captured all ultrasound images. Carcass data collection included 12th rib fat thickness (BFC), 12th rib longissimus muscle area (LMAC) and marbling score (MS). Additionally, Warner Bratzler shear force (WBSF) and ether extraction (EE) estimates were determined on 12 to 13th longissimus muscle samples. All carcass data was collected by the Beef Carcass Research Center (BCRC) at West Texas A&M University. Data were analyzed using SAS version 9.4. Simple descriptive statistics were 1.03 ± 0.26 cm, 88.8 ± 8.61 cm², 5.02 ± 0.93, 1.27 ± 0.36 for BFU, LMAU, %FATU, and RFU, respectively. Simple descriptive statistics were 1.72 ± 0.41 cm, 90.06 ± 7.24 cm², 5.06.7 ± 0.69, 6.08 ± 1.92, and 3.34 ± 0.79 kg for BFC, LMAC and MS, EE and WBSF, respectively. Pearson correlation coefficients were 0.71 (P < 0.001) between BFU and BFC, 0.42 (P < 0.0001) between LMAU and LMAC, and 0.35 (P < 0.001) between %FATU and MS. Pearson correlation coefficients were 0.42 (P < 0.001) between EE and %FATU and 0.59 (P < 0.0001) between EE and MS. These results suggest that ultrasound measures of final body composition should be taken closer to the final harvest date to better estimate endpoints of fat thickness, longissimus muscle area and intramuscular fat in harvest ready beef cattle. [ABSTRACT FROM AUTHOR]

Our objective was to assess whether the harvest processing equipment sanitation practices in beef processing plants are sufficient to mitigate pathogen transfer. Multiple regulatory agencies across the globe require that harvest equipment be sanitized using hot water at a minimum of 82°C, with a momentary dip when a time is specified. Consequently, hot water sanitizers have been widely implemented at meat processing facilities, in particular, for knife sanitation throughout the dressing process. However, there is no standard time requirement for hot water immersion and, as such, the effectiveness of hot water sanitization is uncertain. The practice for knife sanitation at a large beef processing facility was audited and the microbial reduction that simulated the audited practice was assessed along with a momentary dip at 82°C. A five-strain cocktail of Escherichia coli and 11 knives of differing degree of usage obtained from the beef plant were used in the study. An area of 50 cm² of the upper surface of each knife was spread-inoculated with the five-strain E. coli cocktail and the knife was subsequently submerged in a water bath coupled to a water circulator for immersion at 82°C. Exposures times tested were those derived from the in-plant audit for each knife type. A knife that was similarly inoculated, but was not treated with hot water, served as a positive control. E. coli surviving the treatment were enumerated by plating. In addition, two knives that had most and least reduction of E. coli were artificially contaminated with meat prior to inoculation, by passing the knife through meat multiple times. For each condition, three independent trials were conducted. Least-squares means for log counts were separated by a post-hoc Tukey test. Mean immersion times for different knives audited ranged from 1 to 9.8 s. Immersing knives in water at 82°C significantly reduced the number of E. coli (P < 0.05; Table 1), ranging from 2.3 (air knife)- 5.5 (skinning knife 2) log units. Variation among the same knife type was observed. Momentary dip at 82°C reduced E. coli on de-boning, hook, air knife and wizard knife by 1-1.2 log (P < 0.05) and < 1 log for the other six knives (P ≥ 0.05). Treatment at 82°C for the duration of average exposure time observed during the in-plant audit of knives that had been contaminated with meat debris showed lower reductions of E. coli, compared with clean knives. Those reductions (>1.5 log units) were significant (P < 0.05). In conclusion, the duration for hot water sanitation of knives at beef processing plants achieves significant reduction of E. coli if temperature is maintained at 82°C and a momentary dip at the same temperature would be less likely to be effective. [ABSTRACT FROM AUTHOR]

Crossbred beef heifers (N  = 1,394; initial shrunk body weight [BW] 291 ± 9.9 kg) were used to investigate the efficacy of 10-G Armor (Life Products, Inc. Norfolk, NE; 10-G) upon feedlot performance, carcass characteristics, and fecal and subiliac lymph nodes Salmonella prevalence. Heifers were blocked by day of arrival and allocated to 1 of 20 pens (N  = 70 heifers/pen) and assigned one of two treatments (10 pens/treatment): no direct-fed microbial (CON) or 2 g/heifer/d of Lactobacillus acidophilus, Enterococcus faecium, Pediococcus pentosaceus, Lactobacillus brevis and Lactobacillus plantarum , respectively (Life Products, Inc. Norfolk, NE; 10-G). Twenty-four animals were randomly selected from each pen for Salmonella sampling. Recto-anal mucosal swab samples (RAMS) were obtained at initial processing and harvest; subiliac lymph nodes were collected at harvest. In addition, pen surface fecal pats were collected and composited by pen (10 pats per composite, 5 composites per pen) on days 0, 52, 120, and 192. Data were analyzed as a generalized complete block design, and pen served as the experimental unit. No differences were observed in live growth performance metrics (P  ≥ 0.55). Yield grade distributions did not differ between treatments (P  ≥ 0.62); however, cattle fed 10-G tended (P  = 0.06; 14.6% vs. 18.9%) to have fewer USDA Select carcasses and more (P  = 0.09; 73.6% vs. 78.0%) USDA Choice carcasses. Cattle fed 10-G tended (P  = 0.10; 9.2% vs. 12.3%) to have fewer liver abscesses and had fewer (P  = 0.04; 5.3% vs. 8.5%) severe liver abscesses. Salmonella prevalence of RAMS did not differ between treatments at initial processing (P  = 0.97; CON = 11.6%, 10-G = 11.5%) or at harvest (P  = 0.91; CON = 99.0%, 10-G = 98.6%); however, RAMS differed (P  < 0.01) in Salmonella prevalence between the two collection times. Cattle fed 10-G had a lower frequency of Salmonella positive lymph nodes (P  = 0.01; CON = 15.8%, 10-G = 7.4%) than CON. However, Salmonella log (mpn/g) of lymph nodes did not differ between treatments at harvest (P  = 0.34; CON = 0.73, 10-G = 0.34). These data indicate that cattle fed 10-G have decreased rates of severe liver abscesses without altering live animal performance or carcass characteristics. Supplementation of 10-G significantly reduced the prevalence rate of Salmonella recovered from the subiliac lymph nodes. The factors responsible for the observed difference in the effects of 10-G on Salmonella warrant further investigation [ABSTRACT FROM AUTHOR]

Sexed semen artificial insemination is a breeding technique that allows producers to shorten breeding seasons, optimize genetics through use of superior semen, create calves based on sex preference, and increase profitability. Sexed semen is a technology that sorts semen by differences in DNA content between X (female) and Y (male) bearing sperm. However, sexed semen practices have yet to be widely used in beef cows due to reduced sperm numbers, low conception rates, and increased costs. The objective of this study was to determine the effect of time of estrus upon fixed-time artificial insemination (FTAI) of sex-sorted semen on conception rate using two different estrous synchronization protocols. Multiparous commercial beef cows (n = 73) were randomized by age, body condition score (BCS), and days post-partum at the University of Arkansas Livestock and Forestry Research Station in Batesville. Both synchronization treatments (TRT) used a controlled internal drug releasing device (Eazi-breed CIDR; 1.38g progesterone) inserted intravaginally on d -14 of the protocol simultaneous to administration of prostaglandin F2a (PGF; 500μg cloprostenol sodium; Estrumate). In the first treatment (TRT 1; 7&7 Synch), gonadotropin-releasing hormone (GnRH; 86μg gonadorelin; Fertagyl) was administered on d -7. In the second treatment (TRT 2; 8&6 Synch), GnRH was administered on d -6. Both treatments were then administered PGF simultaneous to CIDR removal on d 0, 66 ± 2h before FTAI and administration of GnRH. Standing heat (estrus) was visually detected every 3 h for 30 min intervals between CIDR removal and FTAI. Heat detection patches were used in conjunction with visual detection of estrus. Time of estrus was signified as time of standing immobile when mounted in combination with presenting a patch score of 4 (>75% color removed). Time of estrus (TD) was deviated from time of FTAI and categorized into three equal time groups (Grp 1 = 0 to 11.0 h; Grp 2 = 11.01 to 22.0 h; and Grp 3 = 22.01 to 33.0 h). Conception rate (CR) was determined via ultrasound 37 ± 2 d after FTAI. Data were analyzed using the GLIMMIX procedure of SAS 9.4. CR did not differ by age of dam (P = 0.58), BCS (P = 0.48), or TRT (P = 0.83). However, TD had an effect on CR (P = 0.002); and resulted in CR of 45% (Grp 1), 87% (Grp 2), and 42% (Grp 3). In conclusion, these results indicate artificially inseminating cows with sexed semen between 11.01 and 22.0 h after time of standing estrus will increase pregnancy rates for multiparous commercial beef cattle. [ABSTRACT FROM AUTHOR]

Liver abscesses (LA) are a polymicrobial infection and the causative agents include two subspecies of Fusobacterium necrophorum, necrophorum and funduliforme, and Trueperella pyogenes. Nucleic acidbased analysis of the purulent material of LA has indicated that Proteobacteria and Bacteroidetes were the dominant phyla, next to phylum Fusobacteria. The sporadic isolations of bacterial species of the Proteobacteria and Bacteroidetes in LA have been reported. An aspect of the pathogenesis that has not been investigated is whether bacterial pathogens in LA originate, besides the rumen, from the colon? Therefore, our objectives were to target detection and isolations of Salmonella enterica, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Bacteroides fragilis, in addition to routine isolations of F. necrophorum and T. pyogenes, from LA and also from ruminal and colonic epithelial tissues of the same animals. Liver abscesses, matched with ruminal and colonic epithelial tissue samples from 96 steers and heifers, originating from 15 feedlots, were collected at slaughter, transported to the laboratory and processed within 24 hours. Samples were subjected to anaerobic and aerobic culture methods, including enrichment and selective media for detection and isolation of S. enterica, E. coli, K. pneumonia, P. aeruginosa, and B. fragilis. Prevalence of bacterial species were shown in table 1. For each bacterium, two-sided Fisher's exact test was used to evaluate the association of its prevalence in LA with that in colon and rumen at 0.05 level. Overall, prevalence of subsp. necrophorum, subsp. funduliforme, T. pyogenes and S. enterica in liver abscesses were 86.4% (83/96), 21.8% (21/96), 35.4% (34/96) and 6.2% (6/96), respectively (Table 1). In ruminal tissue samples, prevalence of subsp. necrophorum, subsp. funduliforme, T. pyogenes and S. enterica were 6.6% (6/96), 40.6% (39/96), 11.4% (11/96) and 4.1% (4/96), respectively. Prevalence of subsp. necrophorum, subsp. funduliforme, T. pyogenes and S. enterica in colonic tissues were 18.7% (18/96), 36.4% (35/96), 0% (0/96) and 7.2% (7/96), respectively. Prevalence of E. coli, Klebsiella spp., and P. aeruginosa in LA samples were 70.8% (68/96), 92.7% (89/96), and 91.6% (88/96), respectively. Prevalence of E. coli, Klebsiella spp., and P. aeruginosa in rumen epithelial tissue samples were 17.7% (17/96), 50.0%, (48/96), and 15.6% (15/96), respectively. Prevalence of E. coli, Klebsiella spp., and P. aeruginosa in colonic tissue samples were 16.6% (16/96), 24.0% (26/96), and 12.5% (12/96), respectively. Prevalence of subsp. funduliforme in ruminal and colonic tissues was greater than subsp. necrophorum. None of the liver abscess samples yielded B. fragilis. In conclusion, E. coli was the second most dominant species detected and isolated from LA, next only to subsp. necrophorum. The greater frequencies of isolations of subsp. necrophorum and S. enterica from colonic epithelial than ruminal epithelial tissues suggest that hindgut could also be a source of pathogens involved in LA. [ABSTRACT FROM AUTHOR]