Effects of forage level in feedlot finishing diets on carcass characteristics and palatability of Jersey beef

Jersey cattle are known for producing carcasses with a greater amount of marbling, but they require more days on feed to achieve acceptable market weights compared with other breeds. The objective of this study was to evaluate the effect of dietary forage (12 vs. 24% sudangrass:alfalfa hay, DM basis) in steam-flaked, corn-based finishing diets on carcass characteristics, beef palatability, and retail color stability of steaks from Jersey beef compared with conventionally fed commodity beef strip loins (COM) of identified quality (Choice(-) and Select(+)). Jersey steers (n = 77) were blocked by BW and randomly assigned to 1 of the following treatments for a 383-d trial period: Jersey low 12% (JL; n = 38) or Jersey high 24% (JH; n = 39) forage (DM basis). A comparison group was selected from conventionally fed cattle on the same day of slaughter as the Jersey treatments, and strip loins from USDA Select(+) (COM; n = 20) and Choice(-) (COM; n = 20) were removed for data analysis. Seventy-two hours postmortem, strip loins were removed, vacuum-packaged, and aged at 3°C for 18 d postmortem. After the aging period, steaks from the LM were sliced, vacuum-packaged, and frozen (-20°C) until analyzed. Jersey steaks had reduced (P < 0.05) Warner-Bratzler shear force values compared with COM steaks. Trained sensory panelists rated JL greater (P < 0.05) for initial and sustained tenderness and initial juiciness than COM, whereas JH was intermediate. As expected, marbling was greater (P < 0.05) for both JL and JH compared with COM, and trained sensory panel sustained juiciness, beef flavor intensity, and overall acceptability scores were greater (P < 0.05) for both JL and JH compared with COM; however, no differences (P = 0.14) were reported for consumer tenderness and flavor. Objective color (L*, a*, b*) measurements decreased (P < 0.05) over time across treatments. There were no differences among treatments for lightness (L*); however, overall during retail display JL were less (P < 0.05) red (a*) and yellow (b*) than JH and COM. Subjective color scores indicated both JL and JH were less red (P < 0.05) than COM. Steaks from Jersey were equal to and on some measurements more desirable than steaks from COM carcasses for both color stability and palatability. These results suggest that dietary forage level had minimal effects on carcass characteristics and beef palatability. However, feeding a low-forage diet decreases input cost and potentially results in a greater valued carcass. Finishing long-fed (383 d) Jersey steers can meet beef industry expectations with respect to quality grade.     

Effects of feeding high-oil corn to beef steers on carcass characteristics and meat quality

To assess the effects of feeding high-oil corn on carcass characteristics and meat quality, 60 yearling steers were fed high concentrate diets containing either control corn (82% of diet), high-oil corn (82% of diet), or high-oil corn at a concentration that was isocaloric with the control diet (74% of diet). After being fed for 84 d, steers were slaughtered. At 72 h postmortem, carcass data were collected and rib sections from five steers grading U.S. Choice and five steers grading U.S. Select from each treatment were collected, vacuum packaged, and aged for 14 d. Three steaks (2.54 cm thick) were removed from each rib for Warner-Bratzler shear force measurement, sensory appraisal, and fatty acid composition analyses. Data were analyzed with treatment as the main effect for the carcass data and treatment, quality grade, and two-way interaction in the model for the longissimus data. The two-way interaction was nonsignificant (P > 0.05) for all variables tested. No differences were detected (P > 0.05) in carcass measurements except for marbling scores and quality grades, both of which were greater (P < 0.05) for carcasses from steers fed the high-oil corn. Overall, 78% of steers fed the high-oil corn graded U.S. Choice compared with 47% for the control and 67% for isocaloric group. Shear force and sensory properties of the longissimus were not different (P > 0.05) among treatments. Steaks from U.S. Choice carcasses rated higher (P < 0.05) for tenderness and tended to rate higher (P < 0.10) for juiciness. Feeding the isocaloric and high-oil diets increased (P < 0.05) linoleic acid, arachidonic acid, and the total PUFA content of lipid extracted from the longissimus. Saturated fatty acid percentage was lowest (P < 0.05) for high-oil corn and highest (P < 0.05) for control, with isocaloric being intermediate. Feeding high-oil corn increased (P < 0.05) pentadecyclic acid, margaric acid, and total odd-chain fatty acid content. Feeding high-oil corn in finishing beef cattle diets enhanced intramuscular lipid deposition and increased unsaturation of fatty acids of the longissimus.     

First Isolation of Rotavirus Associated with Neonatal Diarrhoea in Guanacos (Lama guanicoe) in the Argentinean Patagonia Region

Group A rotavirus (RV) and coronavirus (CV) are common viral pathogens associated with neonatal diarrhoea in numerous animal species. The purpose of this work was to investigate the presence of these viral agents in two farm populations of captured guanacos (Lama guanicoe) in the Argentinean Patagonia region, that developed severe diarrhoea outbreaks. Stool and serum samples were analysed for RV and bovine CV antigen and antibody by enzyme‐linked immunosorbent assay. Rotavirus was detected in faeces from two new‐born guanacos with acute diarrhoea, one in each farm. After electrophoretic analysis, each isolated strain, showed a distinctive long dsRNA electropherotype characteristic of group A rotaviruses (4:2:3:2). In addition, 95% (38 of 40) of the sampled animals were positive for RV antibodies, suggesting a high prevalence of RV infection in the populations tested. No evidence of CV circulation by antigen or antibody analysis was observed. To our knowledge, this is the first report of the detection and isolation of RV associated with neonatal diarrhoea in Lama guanicoe.     

Effects of barley variety fed to steers on carcass characteristics and color of meat

This study evaluated the effect of barley varieties in the diets of finishing steers on carcass composition, fat, and lean color and the fatty acid profile of subcutaneous fat. Crossbred steers (391 kg initial BW) were assigned randomly to one of five finishing diets composed primarily of corn (n = 9), Morex barley (n = 9), Steptoe barley, (n = 9), or two experimental barley varieties SM3 (n = 9) and SM5 (n = 9). Grains were cracked prior to feeding. Diets were formulated (DM basis) to be isonitrogenous (2.24% N) and isocaloric (2.01 Mcal/kg NEm and 1.35 Mcal/kg NEg). Steers were slaughtered according to industry-accepted procedures when it was visually estimated that 70% of carcasses would grade USDA Choice. After a 24-h chill at 4 degrees C, carcass quality and yield grade data were collected by trained, experienced university personnel. Objective color (L*, a*, and b*) of both the LM and subcutaneous fat were measured, and samples of subcutaneous fat were removed from the 10th- to 12th-rib region for fatty acid analysis. Diet did not affect hot carcass weight (P = 0.15), fat thickness (P = 0.58), LM area (P = 0.57), percentage of internal fat (P = 0.52), yield grade (P = 0.96), marbling (P = 0.73), or quality grade (P = 0.10). However, the LM from steers fed diets formulated with Morex and SM5 barley varieties tended to be lighter (higher L* values, P = 0.08) than the LM from steers fed the corn-based diet. Additionally, fat from steers fed corn tended to be more yellow (higher Hunter b* values, P = 0.09) than fat from steers fed barley-based diets. Although grain source had only minimal effects on the fatty acid composition of subcutaneous fat samples, pentadecanoic acid (15:0) was greater (P < 0.05) in fat from steers fed SM3 and Steptoe barley varieties than in fat from steers fed corn. Stearic acid (18:0) concentrations were higher (P < 0.05) in fat samples from steers fed corn than in those fed the experimental barley lines (SM3 and SM5). Conversely, fat samples from steers fed Steptoe and SM5 barley had greater (P < 0.05) gadoleic acid (20:1) concentrations than fat from steers fed corn or Morex variety. Although the variety/line of barley included in the finishing diet may affect LM and fat color, grain-source (barley vs. corn) had little effect on beef carcass quality and yield grades and did not greatly alter the fatty acid composition of subcutaneous fat.     

Relaxation of equine tracheal muscle in vitro by different adrenoceptor drugs

Strips of tracheal smooth muscle from 12 horses were contracted by carbachol in tissue baths under isometric conditions. This contraction (≅50% of maximum: EC₅₀) was relaxed completely with adrenoceptor drugs. The only exception was clenbuterol, where the degree of relaxation was ≅90%. In all horses the EC₅₀-value for isoprenaline (mean 1.6 × 10⁻⁸M) was less than that for adrenaline (mean 9.6 × 10^{− 8}M) and noradrenaline (mean 1. 8 × 10_{- 6}M). The potency ratio was 1 < 6 < 110 which indicates that the β₂-subtype dominates among the β-adrenoceptors of equine airways. All preparations were also very sensitive to the specific and potent β₂-receptor agonists clenbuterol (mean 5.7 × 10^{− 9}M) and procaterol (mean 3.6 × 10⁻¹⁰M). No differences in EC₅₀-values due to age, sex and breed were observed in this material. The standard deviation of the mean EC₅₀-values seems to be larger for the specific β₂-adrenoceptor agonists than for the unspecific. A reason for this could be differences in the pattern of the β-adrenoceptor population.     

The use of atropine to control heart rate responses during detomidine sedation in horses

Detomidine is a sedative-analgesic which has a pharmacological profile similar to xylazine. There is evidence that the sedative effects are mediated through alpha-2 adrenoceptors.Cardiopulmonary responses were determined using detomidine as the principal agent and as a preanesthetic prior to the induction of general anesthesia. Compatibility with guaifenesin, sodium thia-mylal and halothane were determined.As in the case of xylazine, detomidine produces a slowing of heart rates. This was found to be either sinus bradycardia or heart block. There may be a corresponding increase in systolic blood pressures. The respiratory pattern is altered through the arterial blood gases and pH data supported evidence of adequate ventilation. The heart rate response to detomidine without anticholinergic treatment was transient and related to he duration of drug action.Atropine sulfate, 0.02 mg/kg i.v. was effective in preventing or treating bradycardia or heart block from detomidine. Heart rates also increased during the administration of guaifenesin and sodium thia-mylal when given 50 min poisit-detomidine.     

Seroprevalence of feline leukemia virus and feline immunodeficiency virus infection among cats in North America and risk factors for seropositivity

OBJECTIVE: To determine seroprevalence of FeLV and FIV infection among cats in North America and risk factors for seropositivity. DESIGN: Prospective cross-sectional survey. ANIMALS: 18,038 cats tested at 345 veterinary clinics (n=9,970) and 145 animal shelters (8,068) between August and November 2004. PROCEDURE: Cats were tested with a point-of-care ELISA for FeLV antigen and FIV antibody. A multivariable random effects logistic regression model was used to identify risk factors significantly associated with seropositivity while accounting for clinic-to-clinic (or shelter) variability. RESULTS: 409 (2.3%) cats were seropositive for FeLV antigen, and 446 (2.5%) cats were seropositive for FIV antibody; 58 (0.3%) cats were seropositive for infection with both viruses. Multivariable analysis indicated that age, sex, health status, and cat lifestyle and source were significantly associated with risk of seropositivity, with adults more likely to be seropositive than juveniles (adjusted odds ratios [ORs], 2.5 and 2.05 for FeLV and FIV seropositivity, respectively), sexually intact adult males more likely to be seropositive than sexually intact adult females (adjusted ORs, 2.4 and 4.66), and outdoor cats that were sick at the time of testing more likely to be seropositive than healthy indoor cats (adjusted ORs, 8.89 and 11.3). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that certain characteristics, such as age, sex, health status, and lifestyle, are associated with risk of FeLV and FIV seropositivity among cats in North America. However, cats in all categories were found to be at risk for infection, and current guidelines to test all cats at the time of acquisition and again during illness should be followed.