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Animal Age (animal + age)
Selected AbstractsThe Paradox of Toughening During the Aging of Tender SteaksJOURNAL OF FOOD SCIENCE, Issue 6 2006Jan Novakofski ABSTRACT:, Aging is the practice of holding meat at low temperatures to improve tenderness that is the most important sensory attribute affecting consumer acceptability of beef. Because of the inconsistencies in measured tenderness changes during aging, we attempted to look at the relationship between aging and initial tenderness irrespective of animal age, genetics, or nutritional status. Cattle were selected to represent a full range of quality grades from Utility to Prime. Steaks from these cattle were aged in vacuum bags for 0, 7, or 14 d and tenderness characteristics were assessed. Steaks were cut from the frozen loin sections, thawed, and cooked on open hearth grills to 70 °C. Sensory evaluation was completed by a 6-member trained sensory evaluation panel and Warner-Bratzler shear was determined. The average shear values decreased with aging time across most grade categories; however, improvement was not uniform. Steaks from Utility grade cattle improved the most while steaks of other grades improved less. Shear values overlapped a great deal across all grades and to gain a better understanding of changes with aging, steaks were grouped based on initial shear value differences of 1 kg. Shear value of the toughest steaks decreased the most during aging (,36%), while those with the lowest shear values increased (16%). The same pattern emerged when steaks were grouped by initial tenderness. These results suggest that initially tough steaks will benefit from aging while very tender steaks may be adversely affected. [source] Pharmacokinetics of flubendazole and its metabolites in lambs and adult sheep (Ovis aries)JOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 6 2009Flubendazole (FLU) is indicated for control of helminthoses in pig and avian species (monogastric animals) and its corresponding pharmacokinetics are well known. The information on FLU's pharmacokinetic behavior in animal species with forestomach (ruminants) has been limited although the use of FLU in these species could be beneficial. The aim of this study was to investigate the pharmacokinetics of FLU and its main metabolites in sheep. The effects of animal age (sexually immature and mature ones) and gender were also studied. FLU was orally administered in a single experimental dose (30 mg/kg of body weight) in the form of oral suspension. Treated immature animals (aged 3 months) and 5 months later the same mature individuals (aged 8 months) were kept under the same conditions (food, water and management) and treated with FLU. Within 72 h after FLU administration, plasmatic samples were collected and FLU and its Phase I metabolites were quantified using high-performance liquid chromatography. FLU was detected in very low concentrations only, reduced FLU (FLU-R) was identified as the main metabolite, and hydrolyzed FLU (FLU-H) as the minor one. Formation of FLU-R was stereospecific with (+)-FLU-R domination. The plasmatic concentrations of (+)-FLU-R reached 10,15 times higher values than those of FLU, (,)-FLU-R and FLU-H. A significant gender effect on pharmacokinetics of FLU or (+)-FLU-R metabolite in the mature animals was found and a wide significant difference between lambs and adult sheep in FLU including both metabolites has been proved. [source] Analysing the isotopic life history of the alpine ungulates Capra ibex and Rupicapra rupicapra rupicapra through their hornsRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 15 2009Inês C. R. Barbosa The horn of ungulate grazers offers a valuable isotopic record of their diet and environment. However, there have been no reports of the spatio-temporal variation of the isotopic composition of horns. We investigated patterns of carbon (,13C) and nitrogen (,15N) isotopic composition along and perpendicular to the horn axis in Capraibex and Rupicaprarupicaprarupicapra to assess the effects of animal age, within-year (seasonal) and inter-annual variation, natural contamination and sampling position on horn isotope composition. Horns of male C. ibex (n,=,23) and R. r. rupicapra (n,=,1) were sampled longitudinally on the front (only R. r. rupicapra) and back side and on the surface and sub-surface. The sides of the R. r. rupicapra horn did not differ in ,13C. In both species, the horn surface had a 0.15, lower ,13C and a higher carbon-to-nitrogen (C/N) ratio than the sub-surface. Washing the horn with water and organic solvents removed material that caused these differences. With age, the ,15N of C. ibex horns increased (+0.1, year,1), C/N ratio increased, and 13C discrimination relative to atmospheric CO2 (13,) increased slightly (+0.03, year,1). Geostatistical analysis of one C. ibex horn revealed systematic patterns of inter-annual and seasonal 13C changes, but 15N changed only seasonally. The work demonstrates that isotopic signals in horns are influenced by natural contamination (,13C), age effects (13, and ,15N), and seasonal (,13C and ,15N) and inter-annual variation (,13C). The methods presented allow us to distinguish between these effects and thus allow the use of horns as isotopic archives of the ecology of these species and their habitat. Copyright © 2009 John Wiley & Sons, Ltd. [source] Age-related changes in semen quality characteristics and expectations of reproductive longevity in Duroc boarsANIMAL SCIENCE JOURNAL, Issue 4 2010Yu Hung HUANG ABSTRACT Quadratic fitting was used to regress semen characteristics of 1441 samples consisting of 12-month collection from 58 Duroc boars against animal age varied from 10 to 80 months. Data was divided into two groups of cool (14.0,22.7°C, RH 81.5%) and hot season (22.9,29.9°C, RH 86.6%), to test effects of age, season and their interactions. Results revealed that young boars of around 1 year old could endure the hot season. The endurance gradually diminished as animals grew. In the hot season animals exhibited peak performance at age around 33 month and it remained for 1 month, while cool-season kept boars could last for 48 months from 16 months old onward. The reproductive longevity should be 51 month in a subtropical environment and it may extend to 70 month if heat stress can be avoided. The estimated total sperm contribution of a Duroc boar would be 1.8 times more when kept below 22°C than in a natural subtropical environment. It is concluded that to maintain Duroc boars as semen donor to at least 4 years of age is feasible in a subtropical environment and boar longevity could reach 6 years old if well kept in a temperate region. [source] Extinction in the developing rat: An examination of renewal effectsDEVELOPMENTAL PSYCHOBIOLOGY, Issue 6 2007Carol S.L. Yap Abstract In the present series of experiments the context-specificity of extinction was examined from a developmental perspective. For postnatal day (PN) 23 rats, renewal of freezing to an aversive odor conditioned stimulus (CS) was observed when rats were conditioned in Context A, extinguished in Context B, and tested in Context A (i.e., ABA renewal). This effect was not observed in PN16 rats, which is consistent with previous studies suggesting that rats <,PN20 are impaired in encoding contextual information [i.e., Carew and Rudy [1991]. Developmental Psychobiology, 24, 191,209]. Subsequent experiments demonstrated that for rats conditioned at PN16 and tested at PN23, contextual regulation of extinction performance depended on the age at which extinction occurred. Specifically, ABA renewal was observed in rats given extinction training at PN22 but not in rats given extinction training at PN17. These latter results show that whether or not context regulates the expression of an ambiguous memory is determined by the animal's age when the memory becomes ambiguous. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 565-575, 2007. [source] Neurotrophin Receptor-like Proteins in the Bovine (Bos taurus) Lymphoid Organs, with Special Reference to Thymus and SpleenANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 4 2001M. B. Levanti Increasing evidence suggests that neurotrophins could regulate immune functions acting directly or indirectly on immunocompetent cells. The indirect pathway involves stromal cells of the primary and secondary lymphoid organs. In the present study the occurrence of Trk proteins (TrkA, TrkB and TrkC), regarded as the high-affinity signal-transducing receptors for neurotrophins, was investigated in cow lymphoid organs using immunohistochemistry. The thymus and spleen of both fetal and adult animals, and the palatine tonsils, lymph nodes and Peyer's patches of adult animals, were analysed. Unidentified cells displaying TrkA-like immunoreactivity were found in the fetal thymus, whereas those expressing this protein in the adult gland were identified as epithelial cells. In the spleen, immunoreactive TrkA was observed in cells of the white pulp. TrkB immunoreactivity in both fetal and adult thymus and spleen was localized in monocyte/macrophage cells. As a rule, TrkC was absent from the thymus and the spleen independent of the animal's age. Different types of stromal cells, but never the lymphocytes themselves, displayed TrkA, TrkB, or TrkC immunoreactivity in the other lymphoid organs analysed. As in other vertebrate species, Trk proteins in the lymphoid organs of the cow were localized in the stromal, non-lymphoid cells, thus suggesting that neurotrophins might regulate the immune function acting indirectly on lymphocytes. [source] | |||||||||||||