Long-term restriction of energy intake without malnutrition is a robust intervention that has been shown to prolong life and delay age-related morbidity. A 1 H NMR-based metabonomic strategy was used to monitor urinary metabolic profiles throughout the lifetimes of control-fed and diet-restricted dogs. Urinary metabolic trajectories were constructed for each dog, and metabolic variation was found to be predominantly influenced by age. Urinary excretion of creatinine increased with age, reaching a maximum between ages 5 and 9 years and declining thereafter. Excretion of mixed glycoproteins was noted at earlier ages, which may be a reflection of growth patterns. In addition, consistent metabolic variation related to diet was also characterized, and energy-associated metabolites, such as creatine, 1-methylnicotinamide, lactate, acetate, and succinate, were depleted in urine from diet-restricted dogs. Both aging and diet restriction altered activities of the gut microbiotia, manifested by variation of aromatic metabolites and aliphatic amine compounds. This analysis allowed the metabolic response to two different physiological processes to be monitored throughout the lifetime of the canine population and may form part of a strategy to monitor and reduce the impact of age related diseases in the dog, as well as providing more general insights into extension of longevity in higher mammals.

. 2000. Monitoring cattle behavior and pasture use with GPS and GIS. Can. J. Anim. Sci. 80: 405-413. Precision agriculture is already being used commercially to improve variability management in row crop agriculture. In the same way, understanding how spatial and temporal variability of animal, forage, soil and landscape features affect grazing behavior and forage utilization provides potential to modify pasture management, improve efficiency of utilization, and maximize profits. Recent advances in global positioning system (GPS) technology have allowed the development of lightweight GPS collar receivers suitable for monitoring animal position at 5-min intervals. The GPS data can be imported into a geographic information system (GIS) to assess animal behavior characteristics and pasture utilization. This paper describes application and use of GPS technology on intensively managed beef cattle, and implications for livestock behavior and management research on pasture. Global positioning system monitoring can provide researchers with efficient and accurate information on grazing behavior. Previous research focused on tracking animals using data gathered by observation. Recent advances in GPS technology have allowed the development of lightweight collar receivers suitable for monitoring animal position at 5-min intervals. Data can be imported into a GIS to assess animal behavior characteristics and pasture utilization. Precision animal location recording allows researchers to evaluate pasture utilization, animal performance, and behavior. Researchers may assess the merits of pasture or paddock shapes and sizes, fence designs, grazing systems, forage composition and availability, location of shade, water, and supplements, and other variables that affect beef cattle operations. The objectives of this article are: 1) to review previous tracking technology; 2) to explain GPS animal monitoring; 3) to describe GPS tracking collar application for beef cattle; and 4) to discuss pasture livestock behavior and management research implications.

Consumption of tall fescue forage infested with the endophytic fungus Acremonium coenophialum can result in a condition termed "fescue toxicosis," which is characterized by decreased weight gains, milk production, conception, and serum prolactin and an inability to dissipate body heat by beef cattle. These decreases in productivity have been estimated to cost beef producers more than $600 million annually. The unthrifty appearance of cattle consuming endophyte-infected tall fescue (E+) is most evident during periods of environmental heat or cold stress, suggesting an interaction with environmental conditions. Without temperature stress, cows consumed similar amounts of E+ and endophyte-free tall fescue (E-). But, when temperatures exceeded 32 degrees C, cows that grazed E+ consumed less forage than cows that grazed E-. After removal of E+ from the diet of steers, compensatory growth was observed, indicating no long-term negative effects of E+. A decrease in serum prolactin but apparently little change in other hormones has been measured after consumption of E+. Under periods of heat stress, animals had reduced ability to dissipate body heat, and blood flow to peripheral (rib skin), core-body (duodenum colon), and brain (cerebellum) tissues was decreased. Due to the depressive effects of E+ on prolactin and heat dissipation, dopamine antagonist therapy has been used in an attempt to rectify these changes. Dopamine antagonists have increased serum prolactin but there is limited evidence to suggest an improvement in heat dissipation. Experiments to elucidate the effects of E+ on alpha-1 and -2 adrenergic receptors may also offer insights into developing strategies to overcome the negative effects of E+ consumption. Preliminary results suggest that injections of an alpha-1 adrenergic antagonist (prazosin) in rats fed E+ under 32 degrees C conditions increased DM intake and reduced rectal temperature.

The relative contributions of genetic selection and dietary regimen on the performance of broilers was assessed. Body weight, feed consumption, mortality (M), and the degree of tibial dyschondroplasia (TD) were measured in the 1957 Athens-Canadian Randombred Control (ACRBC) strain of broilers and in the 1991 Arbor Acres (AA) feather-sexable strain when fed "typical" 1957 and 1991 diets. Energy and protein levels, vitamin and mineral packs, and the coccidiostats used in the two dietary regimens were chosen to be representative of those in use by the industry for the two time periods. Eight treatment groups, i.e., two strains, two sexes, and two dietary regimens, were assigned into four blocks of eight litter floor pens for grow out. The 1957 diets were fed as mash, and the 1991 starter and grower diets were fed as crumbles and pellets, respectively. Feed consumption and BW were recorded at 21, 42, 56, 70, and 84 d of age, a period covering the normal marketing ages for the two broilers. Mortality and the cause of death was recorded daily. The incidence and severity of TD was assessed using a Lixiscope at 42 d of age. Average BW were 190, 508, 790, 1,087, and 1,400 g for the ACRBC on the 1957 diets vs 700, 2,132, 3,108, 3,812, and 4,498 g for the AA on the 1991 diets at 21, 42, 56, 70, and 84 d of age, respectively. The 1991 diets increased the BW of the AA by an average of 14% (20% at 42 d, but only 8% at 84 d) and of the ACRBC by 22%. The BW advantage for the 1991 diet over the 1957 diet for the AA was less for males than for females after 42 d of age, and the advantage decreased with age, probably due to the increasing incidence of leg problems. The M for AA was 9.1% vs 3.3% for the ACRBC at 42 d. Most of the ACRBC M occurred before 21 d, whereas M occurred throughout for the AA, with most after 21 d due to flip-overs and ascites. The feed conversion at 42 d for the ACRBC on the 1957 diet was 3.00 vs 2.04 for the AA on the 1991 diet. The AA on the 1991 diet had a 48.6% incidence of TD vs 25.6% on the 1957 diet. The ACRBC had approximately 1.2% TD on both diets. The TD was more severe with the 1991 diet.

This report reviews decade two of the lifetime diet restriction study of the dog. Labrador retrievers (n 48) were paired at age 6 weeks by sex and weight within each of seven litters, and assigned randomly within the pair to control-feeding (CF) or 25 % diet restriction (DR). Feeding began at age 8 weeks. The same diet was fed to all dogs; only the quantity differed. Major lifetime observations included 1·8 years longer median lifespan among diet-restricted dogs, with delayed onset of late life diseases, especially osteoarthritis. Long-term DR did not negatively affect skeletal maturation, structure or metabolism. Among all dogs, high static fat mass and declining lean body mass predicted death, most strongly at 1 year prior. Fat mass above 25 % was associated with increasing insulin resistance, which independently predicted lifespan and chronic diseases. Metabolizable energy requirement/lean body mass most accurately explained energy metabolism due to diet restriction; diet-restricted dogs required 17 % less energy to maintain each lean kilogram. Metabonomics-based urine metabolite trajectories reflected DR-related differences, suggesting that signals from gut microbiota may be involved in the DR longevity and health responses. Independent of feeding group, increased hazard of earlier death was associated with lower lymphoproliferative responses to phytohaemagglutinin, concanavalin A, and pokeweed mitogen; lower total lymphocytes, T-cells, CD4 and CD8 cells; lower CD8 percentages and higher B-cell percentages. When diet group was taken into account, PWM responses and cell counts and percentages remained predictive of earlier death.Diet restriction: Dog: Ageing: Longevity During 1987, a diet restriction study of domestic dogs (Canis lupus familiaris) was initiated with a hypothesis that 25 % diet restriction would decrease hip joint laxity and osteoarthritis (OA) in a dog breed that is genetically susceptible to obesity and OA (1) .At 24 months, the experiment was extended for the lifetimes of the dogs. The original experimental design was continued with the added hypothesis that 25 % diet restriction (DR) for lifetime would result in increased longevity and improved overall health of DR dogs, compared to pair-mate control-fed (CF) dogs. The last dog died in mid-2001, at age 14·5 years. The database of physiological observations from this study is large and diverse, and earlier communications have occurred over an elapsed time of about 15 years. This report reviews the key findings of the second decade of this work and presents our view of the most important inter-species comparative observations. Overview of general methods Study designLabrador retrievers (n 48) were paired at age 6 weeks by sex and body weight within each of seven litters, and then were assigned randomly within the pair to CF or 25 % DR. Beginning at age 8 weeks, each CF dog was given the dry, extruded diet ad libitum, and each DR pair-mate was given 75 % of the amount of food that its CF pair-mate had consumed the previous day. Each feeding g...

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The present study focused on the hypothesis that dietary supplementation with medium-chain TAG (MCT) will improve cognitive function in aged dogs by providing the brain with energy in the form of ketones. Aged Beagle dogs were subjected to a baseline battery of cognitive tests, which were used to establish cognitively equivalent control or treatment groups. The dogs in the treatment group were maintained on a diet supplemented with 5·5 % MCT. After an initial wash-in period, all the dogs were tested with a battery of cognitive test protocols, which assessed sequentially landmark discrimination learning ability, egocentric visuospatial function and attention. The groups were maintained on the diets for 8 months. The MCT-supplemented group showed significantly better performance in most of the test protocols than the control group. The group differences also varied as a function of task difficulty, with the more difficult task showing greater supplementation effects than the easier tasks. The group given the MCT supplement showed significantly elevated levels of b-hydroxybutyrate, a ketone body. These results indicate, first, that long-term supplementation with MCT can have cognition-improving effects, and second, that MCT supplementation increases circulating levels of ketones. The results support the hypothesis that brain function of aged dogs can be improved by MCT supplementation, which provides the brain with an alternative energy source.Brain ageing: Cognitive functions: Dogs: Medium-chain TAG: Ketone bodies Dog cognitive function, like that of other mammals, becomes impaired over the course of ageing, and it provides a model of human cognitive ageing (1,2) . Decline in energy metabolism is a common feature of ageing in animals, and it is one of the several processes that are closely associated with age-dependent cognitive decline. Rapoport et al. (3) found that brain glucose metabolism was reduced by up to 30 % between 3 and 12 months of age in rats. London et al. (4) reported that brain glucose metabolism was significantly reduced in Beagle dogs at 6 years of age than in 1-year-old dogs. Further changes occurred later in life, but in a manner that varied between brain structures. Brain metabolic decline has also been reported in aged monkeys (5) and human subjects (6) , and it appears to be particularly more pronounced in pathological ageing. Alexander et al.(7) reported that cerebral glucose metabolism was significantly lower in old patients with Alzheimer's disease than in healthy old control subjects. Drzezga et al.(8) traced the development of cognitive decline in patients with mild cognitive impairment, discovering that the clinical symptoms of Alzheimer's disease were associated with further declines in cerebral glucose metabolism. These data suggest that the age-associated reduction in cerebral glucose metabolism is a common feature in ageing, that the process involved may be progressive, starting around the middle age, and that metabolic decline contributes to cognitive decline associated with ...

D uring the 20th century, a large body of research evolved toward understanding aging and how aging can be influenced in individuals and in populations. A considerable portion of this effort has focused on elucidating roles of nutrition, including nutrient requirements during senescence, complications and treatment of chronic diseases, and preventive strategies to delay chronic disease and death. The association among energy intake, energy utilization, and aging is particularly interesting in this respect. The most wellknown intervention is long-term restricted food intake, which has a favorable influence on the life span of species as diverse as nematodes, spiders, rotifers, water fleas, fruit flies, fish, hamsters, mice, rats, and dogs. 1-3 Food restriction also modulates physiologic processes that may influence the expression of diseases that develop later in life. Results of studies 1-6 of rodents, dogs, and primates indicate that food restriction delays age-related death from species-, breed-, and strain-specific causes. Evaluation of lifetime food restriction in a population of dogs offered the opportunity to assess characteristics and predictive aspects of intrinsic (nonenvironmental, arising from inside the body 7,8) death in a large species that has a mean life span that lies intermediately between lower mammals, which have been studied extensively by use of food restriction models, and primates that presently are the subject of similar studies. 1,4-6 The purpose of the data reported here is to describe effects of lifetime food restriction on causes of death and associations among body composition and time of death in dogs. Overall life span data from this study have been previously reported. 2 Materials and Methods Dogs and housing-Forty-eight Labrador Retrievers from 7 litters were allocated to a paired-feeding study design. 9-11 Dogs were paired at 6 weeks of age by sex and body weight within litter and randomly allocated to either a control-fed or restrictedfed group. Dogs were housed in 2 X 19-m indoor-outdoor kennel runs with concrete floors. Free access to outdoors was available, and the activity level of the dogs was not restricted. All dogs were housed in the same environmental conditions for life, with no difference between feeding groups. Kennel assignment was maintained by original pairing, with either 2 (1 pair) or 4 (2 pairs) dogs/kennel. The study was approved by the supervising institutional animal care and use committee. Diets and feeding regimens-Control-fed and restrictedfed dogs ate the same nutritionally complete and balanced noncommercial formula; only the quantity of diet provided was different between feeding groups. 9-11 Beginning at 8 weeks of age, each restricted-fed pair mate was fed a quantity equal to 75% of the amount of food that was consumed on the previous day by the respective control-fed pair mate. When the dogs were 3.25 years old, 2 adjustments were incorporated into the feeding protocol. All dogs were switched from a growth formula containing 27% protein to an adult...