Phenotypic and Functional Characterization of Bovine Adipose-Derived Mesenchymal Stromal Cells.

BACKGROUND: Mesenchymal stem cells (MSCs) are increasingly trialed in cellular therapy applications in humans. They can also be applied to treat a range of diseases in animals, particularly in cattle to combat inflammatory conditions and aging-associated degenerative disorders. We sought to demonstrate the feasibility of obtaining MSCs from adipose tissue and characterizing them using established assays. METHODS: Bovine adipose MSCs (BvAdMSCs) were isolated using in-house optimized tissue digestion protocols and characterized by performing a colony formation assay, cell growth assessments, cell surface marker analysis by immunocytochemistry and flow cytometry, osteogenic and adipogenic differentiation, and secretion of indoleamine 2,3-dioxygenease (IDO). RESULTS: Our results demonstrate the feasibility of successful MSC isolation and culture expansion from bovine adipose tissues with characteristic features of colony formation, in vitro multilineage differentiation into osteogenic and adipogenic lineages, and cell surface marker expression of CD105, CD73, CD90, CD44, and CD166 with negative expression of CD45. BvAdMSCs secreted significant amounts of IDO with or without interferon-gamma stimulation, indicating ability for immunomodulation. CONCLUSIONS: We report a viable approach to obtaining autologous adipose-derived MSCs that can be applied as potential adjuvant cell therapy for tissue repair and regeneration in cattle. Our methodology can be utilized by veterinary cell therapy labs for preparing MSCs for disease management in cattle.

Supplemental trace minerals as complexed or inorganic sources for beef cattle during the receiving period.

To investigate effects of inorganic or complexed trace mineral source (zinc, copper, manganese, and cobalt) on receiving period performance and morbidity, crossbred beef heifer calves (n = 287) arriving on three delivery dates were used in a 42-d receiving trial. Heifers were processed after arrival, stratified by day -1 body weights (BW) and allocated randomly to eight pens (11 to 13 heifers/pen, 24 pens total). Within truckload, pens were assigned randomly to dietary treatment (n = 12 pens/treatment). Heifers were housed on 0.42-ha grass paddocks, provided ad libitum bermudagrass hay and provided dietary treatments in grain supplements fed daily. Treatments consisted of supplemental zinc (360 mg/d), copper (125 mg/d), manganese (200 mg/d), and cobalt (12 mg/d) from complexed (Zinpro Availa 4, Zinpro Corp. Eden Prairie, MN) or inorganic sources (sulfates). Heifers were observed daily for clinical bovine respiratory disease (BRD). If presenting BRD symptoms and rectal temperature ≥ 40 °C, heifers were deemed morbid and treated with antibiotics. Six heifers/pen were bled to determine serum haptoglobin concentrations on days 0, 14, and 28. Liver biopsies were taken on day 5 ±â€…2 and 43 ±â€…1 from three calves selected randomly from each pen for mineral status comparisons. Statistical analyses were performed using the MIXED, GLIMMIX, and repeated measures procedures of SAS 9.4 with truckload as a random effect and pen within truckload specified as subject. There tended to be a treatment by day interaction for BW (P = 0.07). Heifer BW did not differ on day 0 (P = 0.82) and day 14 (P = 0.36), but heifers fed complexed trace minerals had greater BW on day 28 (P = 0.04) and day 42 (P = 0.05). Overall average daily gains were greater for heifers fed complexed trace minerals (P = 0.05; 0.78 vs. 0.70 kg, SE = 0.03). Heifers supplemented with inorganic trace minerals had greater BRD incidence (P = 0.03; 58 vs. 46%, SE = 3.6). Haptoglobin concentrations decreased throughout the trial (P < 0.001), and heifers fed complexed trace minerals tended to have a decrease in haptoglobin concentrations (P = 0.07). The source of trace mineral supplementation had no effect (P ≥ 0.20) on liver mineral concentrations and there were no treatment × day interactions (P ≥ 0.35). In conclusion, supplementing diets for the first 42 d after arrival with complexed trace mineral sources improved heifer performance as compared to heifers supplemented with inorganic trace minerals.

Issues associated with health and management of newly received cattle continue to pose significant animal welfare and economic challenges for the beef industry. Diagnosis of bovine respiratory disease, accompanied with poor growth performance, can be addressed by nutritional intervention in receiving cattle. Trace mineral inclusion in receiving rations is vital to calf performance. There are numerous sources of trace mineral supplements that exist commercially for cattle and their effects on immune function, growth, and performance measures were evaluated. Organic trace mineral supplements are being used in replacement of inorganic salts due to potentially greater bioavailability and functionality. An organic source that is commonly used are amino acid complexes. Replacing inorganic sources with complexed sources of trace minerals (zinc, copper, manganese, and cobalt) improved growth performance and decreased sickness during the 42-d receiving study.

Genomic loci involved in sensing environmental cues and metabolism affect seasonal coat shedding in Bos taurus and Bos indicus cattle.

Seasonal shedding of winter hair at the start of summer is well studied in wild and domesticated populations. However, the genetic influences on this trait and their interactions are poorly understood. We use data from 13,364 cattle with 36,899 repeated phenotypes to investigate the relationship between hair shedding and environmental variables, single nucleotide polymorphisms, and their interactions to understand quantitative differences in seasonal shedding. Using deregressed estimated breeding values from a repeated records model in a genome-wide association analysis (GWAA) and meta-analysis of year-specific GWAA gave remarkably similar results. These GWAA identified hundreds of variants associated with seasonal hair shedding. There were especially strong associations between chromosomes 5 and 23. Genotype-by-environment interaction GWAA identified 1,040 day length-by-genotype interaction associations and 17 apparent temperature-by-genotype interaction associations with hair shedding, highlighting the importance of day length on hair shedding. Accurate genomic predictions of hair shedding were created for the entire dataset, Angus, Hereford, Brangus, and multibreed datasets. Loci related to metabolism and light-sensing have a large influence on seasonal hair shedding. This is one of the largest genetic analyses of a phenological trait and provides insight into both agriculture production and basic science.

A fecal egg count reduction test in grazing beef steers using topical pioneer and generic eprinomectin and fenbendazole oral suspension.

Many generic anthelmintics are commercially available; however, little information exists regarding product effectiveness compared to pioneer brands. The objective of this study was to compare the effectiveness of a generic eprinomectin to the pioneer eprinomectin, as well as to fenbendazole and fenbendazole in combination with the pioneer eprinomectin in grazing beef steers via a fecal egg count reduction test. Forty naturally infected steers were allocated into five treatment groups based on ranked fecal egg counts: 1. pioneer eprinomectin (Eprinex®, topical), 2. generic eprinomectin (Eprizero®, topical), 3. fenbendazole (Safeguard® 0.5% oral suspension), 4. combination of pioneer eprinomectin topical and fenbendazole oral suspension, 5. negative control. Fecal samples were collected on days -14, 0, 14, and 29. Data were analyzed using the MIXED procedure of SAS 9.4. Neither the pioneer nor the generic eprinomectin groups reached a 90% fecal egg count reduction (FECR) throughout the study with reductions of 50% and 11% for pioneer eprinomectin and 79% and - 5% for generic eprinomectin at days 14 and 29 post-treatment, respectively. Both the fenbendazole and combination groups showed 98% and 99% FECR, respectively, at 14 days post-treatment; these reductions dropped slightly at day 29 post-treatment to 94% and 89%, respectively. Primarily Cooperia punctata, Cooperia oncophora and Ostertagia ostertagi larvae were recovered from the coprocultures across all treatment groups. Interestingly, the proportions of C. punctata and C. oncophora essentially demonstrated a post-treatment reversal in the both the fenbendazole and combination treatment groups when comparing days 0 and 29, demonstrating prepatency period differences or a fenbendazole treatment effect.

Effect of bovine respiratory disease on the respiratory microbiome: a meta-analysis.

Background: Bovine respiratory disease (BRD) is the most devastating disease affecting beef and dairy cattle producers in North America. An emerging area of interest is the respiratory microbiome's relationship with BRD. However, results regarding the effect of BRD on respiratory microbiome diversity are conflicting. Results: To examine the effect of BRD on the alpha diversity of the respiratory microbiome, a meta-analysis analyzing the relationship between the standardized mean difference (SMD) of three alpha diversity metrics (Shannon's Diversity Index (Shannon), Chao1, and Observed features (OTUs, ASVs, species, and reads) and BRD was conducted. Our multi-level model found no difference in Chao1 and Observed features SMDs between calves with BRD and controls. The Shannon SMD was significantly greater in controls compared to that in calves with BRD. Furthermore, we re-analyzed 16S amplicon sequencing data from four previously published datasets to investigate BRD's effect on individual taxa abundances. Additionally, based on Bray Curtis and Jaccard distances, health status, sampling location, and dataset were all significant sources of variation. Using a consensus approach based on RandomForest, DESeq2, and ANCOM-BC2, we identified three differentially abundant amplicon sequence variants (ASVs) within the nasal cavity, ASV5_Mycoplasma, ASV19_Corynebacterium, and ASV37_Ruminococcaceae. However, no ASVs were differentially abundant in the other sampling locations. Moreover, based on SECOM analysis, ASV37_Ruminococcaceae had a negative relationship with ASV1_Mycoplasma_hyorhinis, ASV5_Mycoplasma, and ASV4_Mannheimia. ASV19_Corynebacterium had negative relationships with ASV1_Mycoplasma_hyorhinis, ASV4_Mannheimia, ASV54_Mycoplasma, ASV7_Mycoplasma, and ASV8_Pasteurella. Conclusions: Our results confirm a relationship between bovine respiratory disease and respiratory microbiome diversity and composition, which provide additional insight into microbial community dynamics during BRD development. Furthermore, as sampling location and sample processing (dataset) can also affect results, consideration should be taken when comparing results across studies.

Association of maternal temperament and offspring disposition on growth performance.

Animal behavior is complex and varies in definition, depending upon specific traits under observation. Temperament is one component of behavior, that in cattle, is described as the level of fearfulness to a novel or threatening environment. Temperament is a heritable trait which is important since aggressiveness and docility contribute to reproductive success, growth, and carcass quality. We observed maternal temperament at calving and the subsequent influence, if any, on offspring disposition at weaning and their effects collectively on growth performance and carcass traits. Maternal behaviors at calving were observed at four locations within the University of Arkansas system. Cows were assigned a maternal disposition score (MDS) at calving; a scale from 1 to 5 in which aggression decreases. At weaning, calves were assigned a chute score (CS); a scale from 1 to 6 in which aggression increases. Both scoring systems have been previously established. Blood was collected during the 56-d backgrounding period postweaning for blood glucose analysis. Data were analyzed using GLIMMIX procedures of SAS (α = 0.05). The relationship between the two scoring systems was determined with a Pearson correlation (P = 0.22). Animal was the experimental unit and blocked by location for all dependent variables. Location, sex, diet, and MDS were included in the class as covariables for all growth performance and carcass data related to CS. Cows that were more aggressive birthed heavier calves (P < 0.01) compared to indifferent cows. Calves born to cows with either very aggressive or very attentive (MDS of 2 or 3, respectively) scores were heavier upon feedlot entry (P = 0.03) compared to those from indifferent or apathetic cows (MDS of 4 or 5, respectively). Calves defined as nervous and restless (CS of 3 and 2, respectively) were heavier at weaning compared to docile calves (P < 0.01). Restless calves were heavier compared to nervous calves upon arrival and exiting the feedlot (P ≤ 0.01). Calves that were docile at weaning had greater marbling compared to calves that were restless (P ≤ 0.01). Calves that were restless at weaning had greater lean muscle area compared to calves that were nervous (P = 0.05). No definitive relationship was determined between dam and calf temperament. However, the results suggest temperament does impact growth performance and carcass traits but whether the influence comes from the dam or calf temperament, specifically, remains unanswered.

Biodegradable microneedle patch for delivery of meloxicam for managing pain in cattle.

Microneedle patches are a promising source for transdermal diffusion of macromolecules and are designed to painlessly penetrate the skin. In this study, a biodegradable chitosan microneedle patch to deliver meloxicam for managing pain in cattle was tested. The potential of reuse of the polymeric solution to fabricate the patches, optimization of fabrication, morphological analysis of the microneedle patch and analysis of preservation of the chemical composition after sterilization were evaluated. In-vitro analysis consisted of studying in-vitro penetration mechanical properties, compression testing analysis of microneedle patch, and in-vitro drug release analysis. In-vivo studies were performed to analyze the dissolution capability of the microneedle patch. Results regarding the physical characteristics, chemical composition, and mechanical properties confirmed that rheological properties of the chitosan solution, present significant differences over time, demonstrating that reusing the solution on the fourth day results in failure patches. Morphological characteristics and chemical composition studies revealed that the process of sterilization (ethylene oxide gas) needed for implanting the patches into the skin did not affect the properties of microneedle patches. In-vitro studies showed that approximately 33.02 ± 3.88% of the meloxicam was released over 7 days. A full penetration of the microneedles into the skin can be obtained by applying approximately 3.2 N. In-vivo studies demonstrated that microneedle patches were capable of swelling and dissolving, exhibiting a dissolution percentage of more than 50% of the original height of microneedle after 7 days. No abnormal tissue, swelling, or inflammation was observed in the implanted area. The results of this work show that chitosan biodegradable microneedle patches may be useful to deliver meloxicam to improve pain management of cattle with positive effects for commercial manufacturing.

Bovine respiratory microbiota of feedlot cattle and its association with disease.

Bovine respiratory disease (BRD), as one of the most common and costly diseases in the beef cattle industry, has significant adverse impacts on global food security and the economic stability of the industry. The bovine respiratory microbiome is strongly associated with health and disease and may provide insights for alternative therapy when treating BRD. The niche-specific microbiome communities that colonize the inter-surface of the upper and the lower respiratory tract consist of a dynamic and complex ecological system. The correlation between the disequilibrium in the respiratory ecosystem and BRD has become a hot research topic. Hence, we summarize the pathogenesis and clinical signs of BRD and the alteration of the respiratory microbiota. Current research techniques and the biogeography of the microbiome in the healthy respiratory tract are also reviewed. We discuss the process of resident microbiota and pathogen colonization as well as the host immune response. Although associations between the microbiota and BRD have been revealed to some extent, interpreting the development of BRD in relation to respiratory microbial dysbiosis will likely be the direction for upcoming studies, which will allow us to better understand the importance of the airway microbiome and its contributions to animal health and performance.

Identification of Breed Differences in Known and New Fescue Toxicosis Associated Phenotypes in Charolais-and Hereford-Sired Crossbred Beef Cows.

Beef cattle phenotypes are affected by the consumption of toxic fescue. Toxic fescue's impact is dependent on heat stress and breed composition, with genetic variability for robustness to toxin exposure believed to exist within and across breeds. The study objective was to characterize the effect of fescue toxicosis across breeds for known and novel heat and fescue stress-associated phenotypes. One-hundred crossbred fall-calving Charolais- and Hereford-sired cows of parities 1-3 were allocated to graze either toxic fescue (n = 50), non-toxic fescue (n = 25), or a rotation between toxic and non-toxic fescue (n = 25) for 156 days. Phenotypes impacted by breed (genetics) included hair coat score (p < 0.0001), hair reduction/shedding rate (p < 0.05), rectal temperature (RT) (p < 0.0001), vaginal temperature (p < 0.05), serum phosphorus concentration (p < 0.02) and respiration rate (RR) (p < 0.003). Cows on toxic fescue experienced reduced hair shedding efficacy (p < 0.0001), higher vaginal temperatures (p < 0.0001), increased systolic blood pressure (p < 0.04), increased RR (p < 0.0001) and reduced average daily gain (p < 0.0001), compared to cows grazing non-toxic fescue. Calves born from cows with higher RT during the last third of gestation had higher RT at weaning (p < 0.02), indicating potential physiological effects of in utero heat stress. The study indicates that beef cows exhibit variable responses to toxic fescue within and across breeds which may impact future calf phenotypes.

Design, characterization, and modeling of a chitosan microneedle patch for transdermal delivery of meloxicam as a pain management strategy for use in cattle.

This work describes the formulation and evaluation of a chitosan microneedle patch for the transdermal delivery of meloxicam to manage pain in cattle. Microneedle patches composed of chitosan and chitosan/meloxicam were evaluated regarding their chemical composition, uniformity of physical characteristics, capacity to penetrate the skin, and response to thermal and thermo-mechanical changes. Microneedle patches were prepared by varying the percentage of acetic acid used during solution preparation, including 90% (v/v), 50% (v/v), and 10% (v/v). In addition, drug release was assessed by modeling different percentages of penetration into the skin and the number of microneedles on the microneedle patch. Scanning electron microscopy confirmed the presence of microneedles uniformly organized on the patch surface for each percentage of acetic acid used. Fourier transform infrared spectroscopy revealed that 10% (v/v) of acetic acid in the solution was a suitable condition to preserve the characteristic bands of chitosan (amide I and amide II) and meloxicam (amine NH stretch and CO stretch) as compared to 90% (v/v) and 50% (v/v) of acetic acid used during the solution preparation. The resultant microneedle patches were successful in penetrating the skin in a cow's cadaver ear. Results demonstrated that the average depth penetration measured after complete dehydration of the penetrated skin was approximately 78 ± 1 µm. Chitosan and chitosan/meloxicam microneedle patches with higher acetic acid percentages reflected greater resistance to compressive force as temperature increased. Time-dependent simulation of the transport of diluted species by COMSOL revealed that the transdermal drug delivery increases in function to the increment of the number of microneedles on the surface patch and percentage of penetration per microneedle. One patch released a drug concentration of 3.57 × 10-5 mol/m3 in the skin per week, which represents the 26.2% of what is needed for pain management in cattle, established as 1.43 × 10-4 mol/m3. These results demonstrate that chitosan/meloxicam microneedles patches may be suitable to manage pain in cattle after routine procedures.

Genetic Basis of Blood-Based Traits and Their Relationship With Performance and Environment in Beef Cattle at Weaning.

The objectives of this study were to explore the usefulness of blood-based traits as indicators of health and performance in beef cattle at weaning and identify the genetic basis underlying the different blood parameters obtained from complete blood counts (CBCs). Disease costs represent one of the main factors determining profitability in animal production. Previous research has observed associations between blood cell counts and an animal's health status in some species. CBC were recorded from approximately 570 Angus based, crossbred beef calves at weaning born between 2015 and 2016 and raised on toxic or novel tall fescue. The calves (N = ∼600) were genotyped at a density of 50k SNPs and the genotypes (N = 1160) were imputed to a density of 270k SNPs. Genetic parameters were estimated for 15 blood and 4 production. Finally, with the objective of identifying the genetic basis underlying the different blood-based traits, genome-wide association studies (GWAS) were performed for all traits. Heritability estimates ranged from 0.11 to 0.60, and generally weak phenotypic correlations and strong genetic correlations were observed among blood-based traits only. Genome-wide association study identified ninety-one 1-Mb windows that accounted for 0.5% or more of the estimated genetic variance for at least 1 trait with 21 windows overlapping across two or more traits (explaining more than 0.5% of estimated genetic variance for two or more traits). Five candidate genes have been identified in the most interesting overlapping regions related to blood-based traits. Overall, this study represents one of the first efforts represented in scientific literature to identify the genetic basis of blood cell traits in beef cattle. The results presented in this study allow us to conclude that: (1) blood-based traits have weak phenotypic correlations but strong genetic correlations among themselves. (2) Blood-based traits have moderate to high heritability. (3) There is evidence of an important overlap of genetic control among similar blood-based traits which will allow for their use in improvement programs in beef cattle.

The need for a Serious Illness Digital Ecosystem (SIDE) to improve outcomes for patients receiving palliative and hospice care.

Palliative and hospice care services produce immense benefits for patients living with serious illness and for their families. Due to the national shift toward value-based payment models, health systems and payers share a heightened awareness of the need to incorporate palliative and hospice services into their service mix for seriously ill patient populations. During the last decade, a tremendous amount of capital has been invested to better integrate information technology into healthcare. This includes development of technologies to promote utilization of palliative and hospice services. However, no coordinated strategy exists to link such efforts together to create a cohesive strategy that transitions from identification of patients through receipt of services. A Serious Illness Digital Ecosystem (SIDE) is the intentional aggregation of disparate digital and mobile health technologies into a single system that connects all of the actors involved in serious illness patient care. A SIDE leverages deployed health technologies across disease continuums and geographic locations of care to facilitate the flow of information among patients, providers, health systems, and payers. Five pillars constitute a SIDE, and each one is critical to the success of the system. The 5 pillars of a SIDE are: Identification, Education, Engagement, Service Delivery, and Remote Monitoring. As information technology continues to evolve and becomes a part of the care delivery landscape, it is necessary to develop cohesive ecosystems that inform all parts of the serious illness patient experience and identifies patients for the right services, at the right time.

Influence of an immune-modulatory feed supplement on performance and immune function of beef cows and calves preweaning.

The ability to positively alter immune and stress response with nutritional compounds is of great interest and importance to the beef industry. There is a proprietary product (OmniGen-AF [OG]; Phibro Animal Health, Quincy, IL) reported to have performance-enhancing benefits by altering animal response to stress and immune challenges. The objective of this 2-yr research project was to study the effect of supplementing OG to beef cows and their calves on breeding and growth performance. One hundred and twelve multiparous beef cows and 48 primiparous cows were randomly assigned to treatment in year 1; control (CON, no OG; n = 56 multiparous and 24 primiparous) or treatment (OG fed at 8.8 g/100 kg body weight [BW]; n = 56 multiparous and 24 primiparous). Multiparous cows (mean ± SD = 6.4 ± 0.4 yr; BW = 589 ± 9.2 kg; body condition score [BCS] 6.2 ± 0.07) were used in both years of the experiment and primiparous cows (mean ± SD = 2.1 ± 0.04 yr of age, weighed 400 ± 7.5 kg, and BSC of 5.6 ± 0.06) were only used in the first year of the experiment. CON and OG supplements were offered over two production cycles beginning in December approximately 60 d prior to projected calving through pre-breeding in May of each year. Calves from treatment cows were offered treatments in a creep supplement limited to a daily rate of 1% as-fed of BW prorated for 3-d/wk feeding from mid-July through weaning with OG offered at 8.8 g/100 kg BW. Primiparous cow's BW, BCS, and calf performance were not affected by treatment (P ≥ 0.15) in year 1. BW of multiparous OG cows tended (P = 0.10) to be heavier at weaning in year 1 and was greater (P = 0.05) at the onset of the experiment in year 2. Body condition of OG cows was greater (P ≤ 0.02) at weaning in both years 1 and 2, as well as at the onset of the experiment in year 2. Calves fed OG from the mature cows gained more (P = 0.05) BW during the creep feeding period than CON. Core body temperatures of OG heifers measured during the late summer with intravaginal temperature data loggers tended (P ≤ 0.10) to be less at 1400 and 1700 hours and were less (P = 0.05) at 1800 hours than CON heifers. Feeding OG did not result in changes (P = 0.25) in serum titer response to the BVD virus of calves during year 2. The results of the current experiment indicate feeding OG to beef cows and calves can result in improvement in BCS of cows, enhance weight gain of calves preweaning, and reduce heat loads in heifer calves during the late summer.

Carcass traits and consumer acceptability of striploin steaks from band-castrated, intratesticular zinc-injected, or sexually intact beef cattle.

One hundred and eighty beef bulls (BW = 337 ± 10.9 kg) were blocked by BW (6 blocks) and assigned randomly to one of three treatments on day 0: 1) INJ; received 1 mL (100 mg Zn) of a Zn solution in each testis, 2) BAN; received blood-restrictive rubber band placed upon the dorsal aspect of the scrotum, and 3) BUL; bulls with testicles remaining intact. Cattle were grouped by weight block in a randomized complete block design (three treatment pens/block and 10 cattle/pen) and harvested by block on three separate dates when blocks reached similar BW and visual subcutaneous fat thickness depth. Striploins were removed from the left carcass sides, vacuum packaged and aged for 14 d, and then frozen at -20 °C. Frozen striploins were sliced into 2.54-cm-thick steaks and remained frozen until analyses. Steaks (n = 3/animal) were used to assess consumer acceptability via consumer taste panel (n = 152 panelists), Warner-Bratzler shear force, percentage cook loss, and cooked color values. Data were analyzed using mixed model procedures; pen was the experimental unit for all dependent variables. Hot carcass weights and LM area were greater (P < 0.01) for the INJ and BUL treatments compared with BAN. Mean yield grade did not differ between treatments (P = 0.12), although BAN carcasses had smaller LM area (P < 0.01) than BUL or INJ carcasses. Percentage of USDA Choice or better carcasses was greater (P < 0.01) for BAN than INJ and BUL treatments. Consumer panelists detected a difference in perceived tenderness; BAN steaks had greater (P = 0.02) tenderness scores than BUL steaks, whereas INJ steaks were intermediate. Panelists rated juiciness of BAN steaks greater (P < 0.01) than either BUL or INJ steaks. Panelists rated beef flavor greater (P = 0.01) for BAN and BUL steaks than INJ steaks. Overall acceptability was greater (P < 0.01) for BAN compared with INJ steaks, whereas BUL steaks were intermediate. Percentage cook loss of striploin steaks (P = 0.47) and Warner-Bratzler shear force values (P = 0.11) did not differ. Cooked color lightness (L*) and redness (a*) values were not affected (P ≥ 0.23) by treatment. Striploin steaks from BAN and BUL treatments had greater (P = 0.02) yellowness values (b*) than INJ steaks. The ratio of red-to-brown (630:580 nm) of cooked striploin steaks was greater (P = 0.05) for INJ than either BAN or BUL treatments. Carcass and palatability outcomes of INJ were more similar to BUL than BAN, suggesting limited efficacy of INJ in mature beef bulls at feedlot entry.

Zinc injection as a novel castration method in beef bulls: effects on performance, behavior, and testosterone and haptoglobin concentration.

Crossbred beef bulls (n = 180) were blocked by initial BW (337 ± 10.9 kg; six blocks) and assigned randomly to one of three treatments on day 0: 1) INJ; received 1 mL (100 mg Zn) of a Zn solution in each testis, 2) BAN; received blood- restrictive rubber band placed around the dorsal aspect of the scrotum, 3) BUL; bulls with testicles remaining intact in a randomized complete block design (three treatment pens per block and 10 cattle per pen). A subset of 54 animals (n = 3 per pen) was fitted with accelerometers on day 0 to quantify behavior variables continuously for 28 d. Testis width and scrotal circumference, and serum haptoglobin (days 0, 1, 3, 5, 7, and 14) and testosterone concentrations (every 28 d until slaughter) were also determined for the subset. During the slaughter process, testes from INJ and BUL were collected to assess final testes weight and for histopathological evaluation. Data were analyzed using a mixed model (α = 0.05); pen served as the experimental unit for all dependent variables. Final BW was greater (P < 0.01) for INJ and BUL compared to BAN (672, 686, and 611 kg, respectively; SEM = 4.4). Overall ADG and G:F were greater (P ≤ 0.03) in INJ and BUL than BAN; whereas, DMI was similar between treatments for the study duration (P = 0.46). Histopathological evaluation (n = 13; INJ = 7; BUL = 6) indicated that INJ testes were degenerative and reproductively nonviable whereas BUL testes were normal. Serum testosterone concentrations on day 168 were similar (P = 0.14) between INJ and BUL whereas after day 14, BAN was nondetectable; however, initial serum testosterone concentrations were similarly low across treatments. Serum haptoglobin concentration was greater (P < 0.01) in INJ than BUL and BAN on days 1, 3, 5, and 7. Scrotal circumference (P = 0.08) and testis width (P = 0.07) on day 168 tended to be greater for BUL than INJ. Motion index (P ≤ 0.02) and step count (P = 0.04) was greater in BUL and INJ compared to BAN cattle during the 28 d monitoring period. No difference in standing time (P ≥ 0.85) or lying bouts (P = 0.35) occurred. Zinc injection resulted in sterilization but did not cause complete cessation of testicular function evidenced by testosterone concentrations more similar to BUL than BAN. This resulted in overall increased BW and G:F for INJ vs. BAN, yet the acute phase response was markedly greater directly after Zn injection. Collectively, Zn injection resulted in outcomes more similar to BUL than BAN, implying minimal efficacy of INJ as a castration method in older bulls arriving to the feedlot.

Current Status of Parasite Control at the Feed Yard.

Fly and louse infestations are readily discerned and remedied in feedlot cattle. Tapeworm and fluke infections are accepted as probable but, given the lack of anthelmintics with realistic efficacy against these infections, these helminths are allowed to persist without treatment. Nematode infections are considered ubiquitous with cattle coming from pasture and are targeted with a macrocyclic lactone, usually in combination with a benzimidazole. Populations of nematodes seem to be effectively controlled by a combination of anthelmintic treatment, animal resistance and resilience, lack of reinfection, and diet.

Association of hematologic variables and castration status at the time of arrival at a research facility with the risk of bovine respiratory disease in beef calves.

OBJECTIVE: To determine the association of CBC variables and castration status at the time of arrival at a research facility with the risk of development of bovine respiratory disease (BRD). DESIGN: Retrospective cohort study. ANIMALS: 1,179 crossbred beef bull (n = 588) and steer (591) calves included in 4 experiments at 2 University of Arkansas research facilities. PROCEDURES: Calves underwent processing and treatments in accordance with the experiment in which they were enrolled. Castration status and values of CBC variables were determined at the time of arrival at the facilities. Calves were monitored to detect signs of BRD during a 42-day period. RESULTS: The areas under the receiving operator characteristic curves for CBC variables with significant contrast test results ranged from 0.51 (neutrophil count) to 0.67 (eosinophil count), indicating they were limited predictors of BRD in calves. The only CBC variables that had significant associations with BRD in calves as determined via multivariable logistic regression analysis were eosinophil and RBC counts. The odds of BRD for bulls were 3.32 times the odds of BRD for steers. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study indicated that low eosinophil and high RBC counts in blood samples may be useful for identification of calves with a high risk for development of BRD. Further research may be warranted to validate these variables for prediction of BRD in calves. Calves that were bulls at the time of arrival had a higher risk of BRD, versus calves that were steers at that time.