Preslaughter factors affecting mobility, blood parameters, bruising, and muscle pH of finished beef cattle in the United States.

Decades of work have focused on reducing fear, stress, and discomfort in cattle during the preslaughter phase by improving and promoting animal handling, transportation, and management processes. Even still, there is limited information about the effects of preslaughter factors on animal welfare and meat quality outcomes in finished cattle in the United States. This study aimed to track individual animals through the slaughter process to identify preslaughter factors associated with key welfare and quality outcomes. A total of 454 cattle from one commercial slaughter facility were studied. Preslaughter factors assessed included distance traveled, truck waiting time, lairage density, lairage duration, and season. Animal characteristics, i.e., body weight, breed, and sex, were also recorded. One trained observer scored the mobility of all cattle using the North American Meat Institute's 1-4 scale (i.e., normal to extremely reluctant to move). Exsanguination blood was collected and analyzed for cortisol, creatine kinase, and lactate. Carcass bruising was scored using a modified version of the National Beef Quality Audit's bruise-scoring methodology (i.e., no bruise, one bruise ≤ the size of a deck of cards, one bruise > than the size of a deck of cards, and multiple bruises). Ultimate muscle pH was measured 32 to 36 h postmortem. Multi-predictor models were selected for each outcome variable using Akaike Information Criterion. Continuous outcome variables were analyzed using linear mixed-effect models and categorical outcome variables with mixed-effect logistic regression models. Longer truck waiting times were associated with increased cortisol (P = 0.04) and lactate (P = 0.02) concentrations. Similarly, increased lairage duration was associated with increased creatine kinase concentrations (P = 0.05) and the odds of cattle being bruised (P = 0.03). Less space allowance per animal in lairage was associated with increased odds of cattle having impaired mobility (P = 0.01). There was a seasonal effect for many of the measured outcomes; the summer season was associated with greater lactate concentrations (P < 0.0001), increased odds of impaired mobility (P < 0.0001), and increased odds of carcass bruising (P = 0.003). The findings of this study indicate that many of the preslaughter factors assessed influence critical welfare and meat quality outcomes of finished beef cattle, warranting future research and consideration.

Benchmarking current preslaughter management factors, welfare indicators, and meat quality outcomes at commercial fed cattle processing facilities in the United States.

Preslaughter management factors and their impacts on cattle welfare and meat quality are well documented in current literature. However, certain management factors related to transportation and lairage are underrepresented. Benchmarking preslaughter management factors that can impact welfare and meat quality outcomes will allow the industry to identify areas for improvement. The objective of the current study was to benchmark preslaughter management factors for a nationwide sample of commercial fed cattle processing facilities. Five processing facilities in the West, Midwest, and Southwest regions of the United States were sampled from March 2021 to July 2022. Data were collected on a total of n = 637 slaughter lots representing n = 87,220 head of cattle. Variables of interest included general cattle characteristics, distance traveled to the plant, truck wait times to unload, environmental conditions, lairage density, and lairage duration. Additionally, mobility was scored using a four-point locomotion scale (one being normal, not lame, and four being extremely reluctant to move). Carcasses were also observed for bruising using the following scale: no bruises, bruises smaller or larger than a deck of cards, and having multiple bruises. Descriptive statistics were performed on the data at the lot and individual animal level. On average, cattle traveled 155.8 ±â€…209.6 km (mean ±â€…SD) from the feedlot to the processing facility and waited 30.3 ±â€…39.7 min to unload. Once in lairage pens, cattle were held for 200.7 ±â€…195.0 min. The mean lairage stocking density was 3.1 ±â€…2.0 m2 per head. A majority of the cattle scored a mobility score of 1 (n = 77,645, 91.8%), 7.8% (n = 6,125) were scored as a two and the remaining less than one percent of cattle were scored as either a 3 or 4 (n = 265). Carcasses with bruises less than or equal to the size of a deck of cards (n = 22,672, 27.1%) were less frequent than bruises measuring greater than the size of a deck of cards (n = 34,427, 42.6%). Of carcasses that were bruised, 65.2% (n = 39,856) had multiple bruises of varying size. This baseline data on preslaughter management factors identifies opportunities for improvement in wait times, lairage densities, and factors that cause bruising. Future studies should explore the relationships between these factors and their impacts on welfare and meat quality, report the economic value of these outcomes, and explore industry acceptability and adoptability of optimal preslaughter management practices.

Characterizing heat mitigation strategies utilized by beef processors in the United States.

During lairage at slaughter plants, cattle can be exposed to extreme heat conditions from pen densities and holding pen microclimates. While research outlining heat mitigation strategies used in other sectors of the beef supply chain is available, there is no published data on the use of heat mitigation strategies at slaughter plants. The objective of this study was to characterize short-term heat mitigation strategies used by commercial beef slaughter plants in the United States. Twenty-one beef slaughter plants, representing an estimated 60% of beef slaughter in the United States, were included in the study. All plants indicated use of at least one heat mitigation strategy, and five of them used more than one type. Sprinklers/misters were the most commonly used heat mitigation type (n = 17, 81%), and fans were the least common type (n = 4, 19%). Shade usage was present in several plants (n = 7, 33%), ranging from barn style roofs to shade cloths. Respondents indicated that they believed heat mitigation strategies provide benefits both to cattle well-being and meat quality outcomes. Future research should focus on the effectiveness of these techniques in improving animal well-being and quality outcomes in the slaughter plant environment and protocols for optimum implementation.

Willingness to pay for whole turkey attributes during Thanksgiving holiday shopping in the United States.

Although whole turkeys served at Thanksgiving are the ubiquitous kickoffs to the US winter holiday season, much remains unknown about shopping behaviors for holiday food items. Given the once-a-year purchase of the whole turkey for most households, collecting data about demand and preferences necessitated the collection of data during the week before Thanksgiving, while turkey shopping was at the forefront of consumers' minds. Despite a self-reported confidence in cooking turkeys, many respondents indicated they thawed frozen meat using improper methods. Ninety-five percent of respondents indicated that they consumed meat; 89% of respondents who consumed meat or had someone in the household who did, indicated they had purchased turkey products. Positive willingness to pay (WTP) was found for all attributes of whole turkeys studied: free range, fed a vegetarian diet, hormone use not permitted, and antibiotic use not permitted. Mean estimated WTP for free range ranged from $0.37/lb for industry verified free range to $0.74/lb for USDA verified free range; although those 2 estimates were not statistically different from each other, they were both statistically different from zero. The statistically significant estimated mean WTP for hormone use not permitted ranged from $0.85/lb for industry verification to $1.35 for USDA verification but were again not statistically different from each other. Mean WTP estimates, which were statistically significant but not different from one another for antibiotic use not permitted, ranged from $0.62/lb for industry certification to $0.72 for retailer certified. Turkeys certified to be fed a vegetarian diet had a mean WTP estimate of $0.39/lb for retailer verification to $0.60/lb for USDA verification; those mean WTP estimates were not statistically different from each other but were each statistically different from zero. Social desirability bias, which can be defined as the relative over-reporting of one's own goodness, was detected with respect to self-reported holiday eating and healthfulness statements. Relationships were found between social desirability bias, gender, and age for holiday eating statements using a seemingly unrelated regression.

Fibrotic Aortic Valve Stenosis in Hypercholesterolemic/Hypertensive Mice.

OBJECTIVE: Hypercholesterolemia and hypertension are associated with aortic valve stenosis (AVS) in humans. We have examined aortic valve function, structure, and gene expression in hypercholesterolemic/hypertensive mice. APPROACH AND RESULTS: Control, hypertensive, hypercholesterolemic (Apoe(-/-)), and hypercholesterolemic/hypertensive mice were studied. Severe aortic stenosis (echocardiography) occurred only in hypercholesterolemic/hypertensive mice. There was minimal calcification of the aortic valve. Several structural changes were identified at the base of the valve. The intercusp raphe (or seam between leaflets) was longer in hypercholesterolemic/hypertensive mice than in other mice, and collagen fibers at the base of the leaflets were reoriented to form a mesh. In hypercholesterolemic/hypertensive mice, the cusps were asymmetrical, which may contribute to changes that produce AVS. RNA sequencing was used to identify molecular targets during the developmental phase of stenosis. Genes related to the structure of the valve were identified, which differentially expressed before fibrotic AVS developed. Both RNA and protein of a profibrotic molecule, plasminogen activator inhibitor 1, were increased greatly in hypercholesterolemic/hypertensive mice. CONCLUSIONS: Hypercholesterolemic/hypertensive mice are the first model of fibrotic AVS. Hypercholesterolemic/hypertensive mice develop severe AVS in the absence of significant calcification, a feature that resembles AVS in children and some adults. Structural changes at the base of the valve leaflets include lengthening of the raphe, remodeling of collagen, and asymmetry of the leaflets. Genes were identified that may contribute to the development of fibrotic AVS.

Spontaneous Aortic Regurgitation and Valvular Cardiomyopathy in Mice.

OBJECTIVE: We studied the mechanistic links between fibrocalcific changes in the aortic valve and aortic valve function in mice homozygous for a hypomorphic epidermal growth factor receptor mutation (Wave mice). We also studied myocardial responses to aortic valve dysfunction in Wave mice. APPROACH AND RESULTS: At 1.5 months of age, before development of valve fibrosis and calcification, aortic regurgitation, but not aortic stenosis, was common in Wave mice. Aortic valve fibrosis, profibrotic signaling, calcification, osteogenic markers, lipid deposition, and apoptosis increased dramatically by 6 and 12 months of age in Wave mice. Aortic regurgitation remained prevalent, however, and aortic stenosis was rare, at all ages. Proteoglycan content was abnormally increased in aortic valves of Wave mice at all ages. Treatment with pioglitazone prevented abnormal valve calcification, but did not protect valve function. There was significant left ventricular volume overload, hypertrophy, and fetal gene expression, at all ages in Wave mice with aortic regurgitation. Left ventricular systolic function was normal until 6 months of age in Wave mice, but became impaired by 12 months of age. Myocardial transverse tubules were normal in the presence of left ventricular hypertrophy at 1.5 and 3 months of age, but became disrupted by 12 months of age. CONCLUSIONS: We present the first comprehensive phenotypic and molecular characterization of spontaneous aortic regurgitation and volume-overload cardiomyopathy in an experimental model. In Wave mice, fibrocalcific changes are not linked to valve dysfunction and are epiphenomena arising from structurally incompetent myxomatous valves.

Aortic valve sclerosis in mice deficient in endothelial nitric oxide synthase.

Risk factors for fibrocalcific aortic valve disease (FCAVD) are associated with systemic decreases in bioavailability of endothelium-derived nitric oxide (EDNO). In patients with bicuspid aortic valve (BAV), vascular expression of endothelial nitric oxide synthase (eNOS) is decreased, and eNOS(-/-) mice have increased prevalence of BAV. The goal of this study was to test the hypotheses that EDNO attenuates profibrotic actions of valve interstitial cells (VICs) in vitro and that EDNO deficiency accelerates development of FCAVD in vivo. As a result of the study, coculture of VICs with aortic valve endothelial cells (vlvECs) significantly decreased VIC activation, a critical early phase of FCAVD. Inhibition of VIC activation by vlvECs was attenuated by N(G)-nitro-l-arginine methyl ester or indomethacin. Coculture with vlvECs attenuated VIC expression of matrix metalloproteinase-9, which depended on stiffness of the culture matrix. Coculture with vlvECs preferentially inhibited collagen-3, compared with collagen-1, gene expression. BAV occurred in 30% of eNOS(-/-) mice. At age 6 mo, collagen was increased in both bicuspid and trileaflet eNOS(-/-) aortic valves, compared with wild-type valves. At 18 mo, total collagen was similar in eNOS(-/-) and wild-type mice, but collagen-3 was preferentially increased in eNOS(-/-) mice. Calcification and apoptosis were significantly increased in BAV of eNOS(-/-) mice at ages 6 and 18 mo. Remarkably, these histological changes were not accompanied by physiologically significant valve stenosis or regurgitation. In conclusion, coculture with vlvECs inhibits specific profibrotic VIC processes. In vivo, eNOS deficiency produces fibrosis in both trileaflet and BAVs but produces calcification only in BAVs.

The multifunctional Ca²âº/calmodulin-dependent kinase IIδ (CaMKIIδ) regulates arteriogenesis in a mouse model of flow-mediated remodeling.

OBJECTIVE: Sustained hemodynamic stress mediated by high blood flow promotes arteriogenesis, the outward remodeling of existing arteries. Here, we examined whether Ca²âº/calmodulin-dependent kinase II (CaMKII) regulates arteriogenesis. METHODS AND RESULTS: Ligation of the left common carotid led to an increase in vessel diameter and perimeter of internal and external elastic lamina in the contralateral, right common carotid. Deletion of CaMKIIδ (CaMKIIδ-/-) abolished this outward remodeling. Carotid ligation increased CaMKII expression and was associated with oxidative activation of CaMKII in the adventitia and endothelium. Remodeling was abrogated in a knock-in model in which oxidative activation of CaMKII is abolished. Early after ligation, matrix metalloproteinase 9 (MMP9) was robustly expressed in the adventitia of right carotid arteries of WT but not CaMKIIδ-/- mice. MMP9 mainly colocalized with adventitial macrophages. In contrast, we did not observe an effect of CaMKIIδ deficiency on other proposed mediators of arteriogenesis such as expression of adhesion molecules or smooth muscle proliferation. Transplantation of WT bone marrow into CaMKIIδ-/- mice normalized flow-mediated remodeling. CONCLUSION: CaMKIIδ is activated by oxidation under high blood flow conditions and is required for flow-mediated remodeling through a mechanism that includes increased MMP9 expression in bone marrow-derived cells invading the arterial wall.

Osteoprotegerin inhibits aortic valve calcification and preserves valve function in hypercholesterolemic mice.

BACKGROUND: There are no rigorously confirmed effective medical therapies for calcific aortic stenosis. Hypercholesterolemic Ldlr (-/-) Apob (100/100) mice develop calcific aortic stenosis and valvular cardiomyopathy in old age. Osteoprotegerin (OPG) modulates calcification in bone and blood vessels, but its effect on valve calcification and valve function is not known. OBJECTIVES: To determine the impact of pharmacologic treatment with OPG upon aortic valve calcification and valve function in aortic stenosis-prone hypercholesterolemic Ldlr (-/-) Apob (100/100) mice. METHODS: Young Ldlr (-/-) Apob (100/100) mice (age 2 months) were fed a Western diet and received exogenous OPG or vehicle (N = 12 each) 3 times per week, until age 8 months. After echocardiographic evaluation of valve function, the aortic valve was evaluated histologically. Older Ldlr (-/-) Apob (100/100) mice were fed a Western diet beginning at age 2 months. OPG or vehicle (N = 12 each) was administered from 6 to 12 months of age, followed by echocardiographic evaluation of valve function, followed by histologic evaluation. RESULTS: In Young Ldlr (-/-) Apob (100/100) mice, OPG significantly attenuated osteogenic transformation in the aortic valve, but did not affect lipid accumulation. In Older Ldlr (-/-) Apob (100/100) mice, OPG attenuated accumulation of the osteoblast-specific matrix protein osteocalcin by ∼80%, and attenuated aortic valve calcification by ∼ 70%. OPG also attenuated impairment of aortic valve function. CONCLUSIONS: OPG attenuates pro-calcific processes in the aortic valve, and protects against impairment of aortic valve function in hypercholesterolemic aortic stenosis-prone Ldlr (-/-) Apob (100/100) mice.

The impact of prolonged rotary ventricular assist device support upon ventricular geometry and flow kinetics.

BACKGROUND: The aim of this study was to determine the impact of prolonged left ventricular assist device (VAD) support on cardiac ventricular geometry and VAD flow kinetics. METHODS: Nineteen patients with end-stage heart failure underwent the implantation of HeartMate II rotary flow VADs. Left and right ventricular geometry and VAD flow kinetics were assessed by transthoracic echocardiography early (7 ± 1 days) and late (113 ± 21 days) after VAD implantation. RESULTS: Left ventricular end-diastolic internal dimension decreased by 21% and 35%, respectively, early and late after VAD implantation (n = 19; P < .001 vs before VAD implantation). Right ventricular end-diastolic internal dimension did not decrease at either time. Hemodynamic trends were similar. VAD inflow obstruction by myocardium was observed in eight patients, seven of whom demonstrated significantly increased variation of VAD inflow during the cardiac cycle ("pulsatility") detected by Doppler studies. Medical or surgical intervention returned VAD flow patterns toward baseline in seven of eight patients with VAD obstructions. CONCLUSIONS: Prolonged rotary VAD support unloads the left ventricle, with modest effects on the right ventricle. These changes are often associated with alterations of VAD flow kinetics, requiring therapeutic intervention. These findings indicate the usefulness of echocardiographic surveillance in patients undergoing prolonged VAD support.