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Ordakowski-Burk, A. L., Quinn, R. W., Shellem, T. A., & Vough, L. R. (2006). Voluntary intake and digestibility of reed canarygrass and timothy hay fed to horses. J. Anim Sci., 84(11), 3104–3109.
Abstract: Thousands of hectares of timothy (Phleum pretense L.) grown in the Mid-Atlantic region are infected by cereal rust mite (Abacarus hysterix) that causes discoloration and curling of leaves, decreased nutritional quality, and substantial decreases in yield. A decline in production of timothy hay can lower income for hay producers and cause horse owners to search for alternative hays. Low alkaloid reed canarygrass (Phalaris arundinacea L.) hay has potential as an alternative to timothy hay because it grows well in the Mid-Atlantic region, is believed to have a similar nutrient quality to timothy, and is not as susceptible to cereal rust mite. Eleven mature, stalled Thoroughbred geldings (549 +/- 12.1 kg) that were exercised daily were used to compare voluntary DMI and apparent nutrient DM digestibility of timothy and low-alkaloid Chiefton variety reed canarygrass hay. Horses were paired by age and BW and randomly assigned to timothy or reed canarygrass hay during a 14-d period to measure voluntary DMI followed by a 4-d period to measure apparent DM digestibility. Both hays met the minimum requirements for DE, CP, Ca, P, K, Fe, and Mn, but they did not meet the minimum requirements for Cu, Zn, and Na for horses at maintenance and averaging 550 kg of BW. Timothy hay seemed to have a lower CP concentration (14.4%) compared with reed canarygrass hay (17.1%) and a more desirable Ca:P ratio at 1.6:1 compared with 0.8:1 for reed canarygrass hay. Horses fed timothy consumed more hay (P <0.001) during the voluntary DMI period compared with horses fed reed canarygrass. Greater voluntary DMI of timothy occurred on d 1, 3, and 5 (P <0.05), but DMI was similar for other days. Apparent DM digestibility was greater in horses fed timothy hay by 9.6% compared with horses fed reed canarygrass hay (P <0.05). Horses fed timothy had greater DM digestibility of ADF (P = 0.001), NDF (P = 0.001), sugar (P = 0.05), and Ca (P = 0.001) but lower apparent DM digestibility of CP (P = 0.012) and crude fat (P = 0.004). Timothy hay was superior in voluntary DMI and apparent DM digestibility compared with low-alkaloid reed canarygrass hay fed to horses.
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Sappington, B. F., & Goldman, L. (1994). Discrimination learning and concept formation in the Arabian horse. J. Anim Sci., 72(12), 3080–3087.
Abstract: Discrimination learning and concept formation abilities were investigated in four mature Arabian horses. A series of two-choice discrimination problems were presented on stimulus panels that could open to allow access to food bowls. Selection of the correct stimulus resulted in food reinforcement, and an incorrect choice was not rewarded. The positions of the correct and incorrect stimuli were varied randomly during each test session, and the criterion for learning each problem was 85% correct for two consecutive sessions of 30 or 40 trials. Testing progressed through six discrimination problems. The first four were simple pattern discriminations, but the last two incorporated several different triangles as correct stimuli and thus involved the concept of triangularity. Two of the subjects successfully completed only simple pattern discriminations, one showed evidence of learning in the first concept problem, and one completed all six tests, including the two concept formation problems. The results demonstrate complex pattern discrimination ability in horses, and suggest that they may also have the ability to form and use concepts in problem solving.
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Apple, J. K., Kegley, E. B., Galloway, D. L., Wistuba, T. J., Rakes, L. K., & Yancey, J. W. S. (2006). Treadmill exercise is not an effective methodology for producing the dark-cutting condition in young cattle. J. Anim Sci., 84(11), 3079–3088.
Abstract: Holstein steer calves (n = 25) were used to evaluate the effects of treadmill exercise (TME) on blood metabolite status and formation of dark-cutting beef. Calves were blocked by BW (156 {+/-} 33.2 kg) and assigned randomly within blocks to 1 of 5 TME treatments arranged in a 2 x 2 factorial design (4 or 8 km/h for a duration of 10 or 15 min) with a nonexercised control. Venous blood was collected via indwelling jugular catheters at 10, 2, and 0 min before TME and at 2-min intervals during exercise. Nonexercised steers were placed on the treadmill but stood still for 15 min. Serum cortisol levels, as well as plasma concentrations of glucose, lactate, and NEFA, were similar (P > 0.05) before TME. Serum cortisol concentrations were unaffected (P > 0.05) during the first 6 min of TME, but between 8 and 15 min of TME, cortisol concentrations were greater (P < 0.05) in steers exercised at 8 km/h than those exercised at 4 km/h or controls (speed x time, P < 0.001). Although TME did not affect (P > 0.05) plasma glucose levels, plasma lactate concentrations in steers exercised at 8 km/h increased (P < 0.05) sharply with the onset of the TME treatment and remained elevated compared with steers exercised at 4 km/h or unexercised controls (speed x time, P < 0.001). Exercised steers had the lowest (P < 0.05) plasma NEFA concentrations during the first 6 min of TME compared with unexercised steers; however, NEFA concentrations were similar after 10 and 12 min of TME, and by the end of TME, steers exercised at 8 km/h had greater (P < 0.05) NEFA levels than nonexercised controls or steers exercised at 4 km/h (speed x time, P < 0.001). Even though muscle glycogen levels and pH decreased (P < 0.001) and muscle lactate concentrations increased (P < 0.001) with increasing time postmortem, neither treadmill speed nor TME duration altered postmortem LM metabolism. Consequently, there were no (P > 0.05) differences in the color, water-holding capacity, shear force, or incidences of dark-cutting carcasses associated with preslaughter TME. It is apparent that preslaughter TME, at the speeds and durations employed in this study, failed to alter antemortem or postmortem muscle metabolism and would not be a suitable animal model for studying the formation of the dark-cutting condition in ruminants.
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Pere, M. C. (1995). Maternal and fetal blood levels of glucose, lactate, fructose, and insulin in the conscious pig. J. Anim Sci., 73(10), 2994–2999.
Abstract: To study nutrition and metabolism in the fetal pig, a chronic catheterization method was developed that allows blood sampling in arteries and veins, at both the umbilical and uterine sources, in the conscious, unstressed animal. A catheter was inserted in the fetal aorta through a femoral artery, and another one was introduced in the umbilical vein. A catheter was put in a femoral artery of the sow so that its end was in the abdominal aorta. A fourth catheter was placed in a uterine vein draining the fetoplacental unit studied. This procedure was applied to 18 Large White primiparous sows at 99 d of gestation. Blood samples were drawn simultaneously using the four catheters before a meal at 103 d of pregnancy, and glucose, insulin, lactate, and fructose were determinated. Glycemia was 2.5 times higher in the sow than in the fetus. The extraction coefficient of glucose by the fetus amounted to 14% of the umbilical supply. The insulin level in the fetal pig was very low ( < 5 microU/mL). Lactate and fructose seemed to originate from the placenta. Blood lactate was 2.6 times lower in the sow than in the fetus, and its extraction coefficient by the fetus amounted to 8%. Fructose in the fetal blood was 2.3 times higher than that of glucose. Fructose was not utilized by the pig fetus. The present results obtained in the fetal pig are comparable to the conclusions drawn from studies with other species.
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Marshall, T. T., Hoover, T. S., Reiling, B. A., & Downs, K. M. (1998). Experiential learning in the animal sciences: effect of 13 years of a beef cattle management practicum. J. Anim Sci., 76(11), 2947–2952.
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Swanson, J. C. (1995). Farm animal well-being and intensive production systems. J. Anim Sci., 73(9), 2744–2751.
Abstract: Animal welfare, or well-being, is a social issue with ethical, scientific, political, and aesthetic properties. Answering questions about the welfare of animals requires scientific definition, assessment, solutions, and public acceptance. With respect to the actual well-being of the animal, most issues are centered on how the animal “feels” when managed within a specific level of confinement, during special agricultural practices (e.g., tail docking, beak trimming, etc.) and handling. Questions of this nature may require exploration of animal cognition, motivation, perception, and emotional states in addition to more commonly recognized indicators of well-being. Several general approaches have emerged for solving problems concerning animal well-being in intensive production systems: environmental, genetic, and therapeutic. Environmental approaches involve modifying existing systems to accommodate specific welfare concerns or development of alternative systems. Genetic approaches involve changing the behavioral and (or) physiological nature of the animal to reduce or eliminate behaviors that are undesirable within intensive system. Therapeutic approaches of a physical (tail docking, beak trimming) and physiological (drug and nutritional therapy) nature bring both concern and promise with regard to the reduction of confinement stress. Finally, the recent focus on commodity quality assurance programs may indirectly provide benefits for animal well-being. Although research in the area of animal well-being will provide important information for better animal management, handling, care, and the physical design of intensive production systems there is still some uncertainty regarding public acceptance. The aesthetics of modern intensive production systems may have as much to do with public acceptance as with science.
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Watts, J. M. (1998). Animats: computer-simulated animals in behavioral research. J. Anim Sci., 76(10), 2596–2604.
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Steelman, S. M., Michael-Eller, E. M., Gibbs, P. G., & Potter, G. D. (2006). Meal size and feeding frequency influence serum leptin concentration in yearling horses. J. Anim Sci., 84(9), 2391–2398.
Abstract: Energy is an essential nutrient for all horses, and it is especially important in performance horses, pregnant and lactating mares, and young growing horses. A negative energy balance in horses such as these may result in unsatisfactory performance, decreased fertility, or slow growth. Therefore, ensuring adequate energy intake is an important aspect of the nutritional management of the equine. This study was undertaken to investigate the effects of feeding large, carbohydrate-rich, concentrate meals on the satiety-inducing hormone, leptin. Three groups of yearling horses were rotated through 3 feeding schedules in a replicated 3x3 Latin square design. Horses were fed 2, 3, or 4 times per day (2x, 3x, and 4xfeeding schedules, respectively), each for a period of 11 d, with the total amount of daily feed held constant. Horses were weighed and BCS was determined on the first day of each period. Blood samples were collected before the morning meal on d 1, 4, and 7 of each period. Additionally, blood was sampled for the last 24 h of the 2xand 4xdietary periods. Neither weight nor BCS changed during the study (P = 0.99 and P = 0.28, respectively). Both mean and peak plasma glucose were greatest in 2xhorses (P < 0.05), as were mean areas under the curve. Serum leptin concentration increased in 2xhorses (P < 0.05), but not in horses fed 3 or 4 times daily. Leptin was elevated in horses with greater BCS (P < 0.05) and increased steadily throughout the study (P < 0.05). Data from the 24-h collection indicated that 2xhorses had fluctuations in leptin production throughout the day (P < 0.05), whereas horses fed 4 times daily did not. Overall, this study indicates that feeding horses 2 large concentrate meals daily can increase mean serum leptin concentrations and may cause fluctuations in leptin production over a 24-h period. This departure from baseline leptin concentration has the potential to affect appetite, along with numerous other physiological processes.
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Houpt, K. A., Zahorik, D. M., & Swartzman-Andert, J. A. (1990). Taste aversion learning in horses. J. Anim Sci., 68(8), 2340–2344.
Abstract: The ability of ponies to learn to avoid a relatively novel food associated with illness was tested in three situations: when illness occurred immediately after consuming a feed; when illness occurred 30 min after consuming a feed; and when illness was contingent upon eating one of three feeds offered simultaneously. Apomorphine was used to produce illness. The feeds associated with illness were corn, alfalfa pellets, sweet feed and a complete pelleted feed. The ponies learned to avoid all the fees except the complete feed when apomorphine injection immediately followed consumption of the feed. However, the ponies did not learn to avoid a feed if apomorphine was delayed 30 min after feed consumption. They could learn to avoid alfalfa pellets, but not corn, when these feeds were presented with the familiar “safe foods,” oats and soybean meal. Ponies apparently are able to learn a taste aversion, but there were constraints on this learning ability. Under the conditions of this study, they did not learn to avoid a food that made them sick long after consumption of the food, and they had more difficulty learning to avoid highly palatable feeds.
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Gonyou, H. W. (1994). Why the study of animal behavior is associated with the animal welfare issue. J. Anim Sci., 72(8), 2171–2177.
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