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We tested the effects of age, sex, and season on the nutritional strategies of a group of mountain gorillas (Gorilla beringei) in the Bwindi Impenetrable National Park, Uganda. Through observations of food intake of individual gorillas and nutritional analyses of dietary components over different seasons and environments, we estimated nutrient intake and evaluated diet adequacy. Our results suggest that the nutritional costs of reproduction and growth affect nutrient intake; growing juveniles and adult females ate more food and more protein per kilogram of metabolic body mass than did silverbacks. The diets of silverback males, adult females, and juveniles contained similar concentrations of protein, fiber, and sugar, indicating that adult females and juveniles did not select higher protein foods than silverbacks but rather consumed more dry matter to ingest more protein. Juveniles consumed more minerals (Ca, P, Mg, K, Fe, Zn, Mn, Mo) per kilogram of body mass than adult females and silverback males, and juveniles consumed diets with higher concentrations of phosphorous, iron, and zinc, indicating that the foods they ate contained higher concentrations of these minerals. Seasonally, the amount of food consumed on a dry weight basis did not vary, but with increased frugivory, dietary concentrations of protein and fiber decreased and those of water-soluble carbohydrates increased. Energy intake did not change over the year. With the exception of sodium, gorillas ate diets that exceeded human nutrient requirements. A better understanding of the relative importance of food quantity and quality for different age-sex classes provides insights into the ways in which gorillas may be limited by food resources when faced with environmental heterogeneity.

Foods eaten by gorillas (Gorilla beringei) in Bwindi Impenetrable National Park (BINP), Uganda, were analyzed for their nutrient content. The goal of the study was to assess the amounts of fiber, protein, and sugars in the foods eaten by the Bwindi gorillas, and to determine whether condensed tannins and cyanide are present in these foods. A total of 127 food plant parts representing 84 plant species eaten by two groups of Bwindi gorillas were collected, processed, and analyzed for their chemical contents. The Bwindi gorilla ate foods that contain 2-28% crude protein (CP), 21-88% neutral detergent fiber (NDF), 14-60% acid detergent fiber (ADF), 2-42% acid detergent lignin (ADL), and

Objective: To determine whether equine motor neuron disease (EMND) could be induced in adult horses fed a diet low in vitamin E and high in copper and iron., Animals: 59 healthy adult horses., Procedure: Horses in the experimental group (n = 8) were confined to a dirt lot and fed a concentrate low in vitamin E and high in iron and copper in addition to free-choice grass hay that had been stored for 1 year. Control horses (n = 51) were fed a concentrate containing National Research Council-recommended amounts of copper, iron, and vitamin E. The hay fed to control horses was the same as that fed to experimental horses, but it had not been subjected to prolonged storage. Control horses had seasonal access to pasture, whereas experimental horses had no access to pasture. Horses that developed clinical signs of EMND were euthanatized along with an age-matched control horse to determine differences in hepatic concentrations of vitamin E, vitamin A, copper, iron, and selenium., Results: 4 experimental horses developed clinical signs of EMND. Plasma concentrations of vitamin E decreased in all 8 experimental horses. There were no significant changes in plasma concentrations of vitamin A, selenium, and copper or serum concentrations of ferritin. There were no significant differences in those analytes between experimental horses with EMND and experimental horses that did not develop EMND. No control horses developed EMND., Conclusions and Clinical Relevance: Results suggest that lack of access to pasture, dietary deficiency of vitamin E, or excessive dietary copper are likely risk factors for EMND.

To test the hypothesis that routine dental correction (removal only of sharp hooks and points from molars and premolars) would improve digestion of a hay/grain ration whereas performance 'floats' (rounding and smoothing of the dental arcades) would adversely affect digestion, 8 mature horses free from dental correction for over a year were used. Five-day digestion trials were conducted before and 2 and 4 weeks after correction in all horses. Although all horses had sharp points and minor premolar hooks, none had severe dental abnormalities. There were no significant differences found in apparent digestion of dry matter, crude protein, neutral detergent fibre or acid detergent fibre relative to precorrection data or controls (uncorrected horses on same digestion trial). Apparent digestibility of crude protein and fibre, however, was reduced if the occlusal angle of premolar 307 was greater than 80 degrees relative to the vertical axis (flattened). It should be recommended that regular dental correction be continued. However, if only small points and hooks are present, correction will not significantly improve digestion. Performance floating does not adversely affect digestion 2-4 weeks after the procedure is performed. Alterations in molar occlusal surface angle may affect digestibility of protein and fibre.

The Battle of Little Bighorn was fought over 100 y ago but many controversies remain. Some feel the defeat of Custer could have been avoided if Benteen and Reno had united with Custer. A slow-moving pack train may have hindered the troops of Benteen and Reno from joining up with Custer. One report indicated the horses and mules in the pack train were lame and behaved crazily. It has been previously suggested that the animals had selenium toxicosis. We propose the lameness could have been caused by selenium, but that the behavioral problems may have been caused by the ingestion of plants containing swainsonine.

Objective: To determine whether feeding a low-carbohydrate, high-fat diet would decrease severity of exercise-induced muscle injury in horses with exertional rhabdomyolysis., Animals: 19 horses with a history of exertional rhabdomyolysis., Design: Case series., Procedure: Specimens of the semitendinosus or semimembranosus muscle were obtained for histologic examination, and serum creatine kinase (CK) and aspartate transaminase (AST) activities 4 hours after exercise were determined. Horses were then fed a low-carbohydrate, high-fat diet, and serum CK and AST activities 4 hours after exercise were reevaluated at approximately monthly intervals for 3 to 6 months., Results: Serum CK and AST activities 4 hours after exercise were high before any change in diet. All 19 horses had evidence of chronic myopathic change and abnormal glycogen accumulation in muscle biopsy specimens; 11 horses also had evidence of complex polysaccharide accumulation. Adaptation to diet change required approximately 3 to 6 months. Sixteen horses did not have any episodes of exertional rhabdomyolysis after 3 to 6 months of diet change, and 3 horses had mild episodes of exertional rhabdomyolysis following either a reduction in dietary fat intake or restriction in exercise. Postexercise serum CK and AST activities 3 to 6 months after the change in diet were significantly less than initial values., Clinical Implications: Results indicated that exertional rhabdomyolysis may be a result of abnormal carbohydrate metabolism in some horses. Feeding a diet with low carbohydrate and high fat content may reduce severity of exercise-induced injury in some horses with exertional rhabdomyolysis.

Accurate estimates of body weight can be useful in the evaluations of feeding programs, nutritional status and general health, and in calculation of dose levels (such as for anesthesia)-thus providing a valuable tool for captive elephant management. We used body measurements of 75 Asian elephants (Elephas maximus) to predict body weight. Weight, heart girth, height at the withers, body length, and foot-pad circumference were measured. All possible linear regressions of weight on one, two, three, or four body measurements were calculated. The highest correlation with a single measurement was that between heart girth and weight (R2 = 0.90). The data were also divided into age groups (1-13, 18-28, 29-39, and 40-57 yr), and all possible linear regressions were calculated for each group (there were no elephants aged 14-17 yr). Adding body length or pad circumference to heart girth resulted in a slight increase in R2. We conclude that body weight in Asian elephants can be predicted from body measurements and that heart girth is the best predictor. A second body measurement might improve predictive accuracy for some age groups.

Four mature Standardbred horses were used in a 2-period cross-over design experiment to evaluate the effect of feeding state (fed or fasted) on metabolic response to 2 repeated bouts of exercise. Horses were either fasted 15 to 16 h before exercise or fasted for 12 h and then fed 2 kg of whole corn 2.5 to 3 h before exercise. In the first period, 2 horses in each feeding state were exercised. In the second period, the treatments were switched. The exercise test consisted of 2 exercise bouts separated by a 90 min recovery period. Each exercise bout included a warm-up phase and a high intensity phase (1600 m at 11 m/s on a 2% graded treadmill). Blood samples collected during the exercise test were analysed for glucose, non-esterified fatty acids (NEFA), insulin and lactate concentrations. Fasted horses had lower insulin concentrations and higher NEFA concentrations at the onset of exercise (P < 0.05). NEFA concentrations were consistently higher (P < 0.05) in the fasted horses until the high intensity phase of the second exercise bout. Feeding state did not affect heart rate or plasma lactate responses to exercise. Plasma glucose concentrations tended to decline in the fed horses during the first exercise bout. Neither a positive nor a negative effect of feeding state on horses performing repeated bouts of intense exercise were found.

Some aspects of energy, protein and vitamin E nutrition of the performance horse are discussed. The amount, dietary source and time of ingestion of energy before exercise can influence performance. In 1989 the National Research Council (NRC) increased their estimates of energy required by racehorses. Recent studies indicate that the increase was reasonable. Many factors, however, can influence energy requirements. Therefore, the best measure would be body weight and composition of the horse. A proper balance of soluble carbohydrate, fiber, fat and protein is essential. Some guidelines are presented. The amount and type energy source given before exercise can influence level of plasma glucose and free fatty acids during exercise, but the effects of these changes in the concentration of metabolites remains to be determined. There is no evidence that increased dietary concentrations of protein are needed and, in fact, may impair performance. Supplemental histidine (to enhance carnosine levels) or carnitine appear to be of limited value for horses fed conventional diets. Dietary concentrations of vitamin E less than the 80 IU/kg recommended by NRC seem to adequately protect against exercise-induced peroxidation. The NRC value may be justified on the basis of immune response, but further studies are needed. Vitamin E has been shown to be involved with familial equine degenerative myeloencephalopathy and may be involved with equine motor neuron disease, a condition considered to be similar to amyotrophic lateral sclerosis in humans.

Oxygen consumption (VO2) and concentration of venous blood metabolites were measured in donkeys trained to run and to pull loads on a treadmill. VO2 in two donkeys running at maximal speed on a 9.8% slope was 110 +/- 2 ml.min-1.kg-1, approximately 22 times preexercise VO2. Average heart rate at maximal VO2 (VO2max) was 223 +/- 2 beats/min, five times the preexercise heart rate. Blood lactate increased 14-fold, and blood glucose did not change (P > 0.05). Animals running up a 4% incline and incremental draft loading of five donkeys walking on the level were also studied. The total energy cost of walking unloaded was 2.86 +/- 0.06 J.m-1.kg live wt-1. During low- to medium-intensity draft work for 25 min, glucose fell below preexercise values (P < 0.05), whereas plasma hematocrit and cortisol increased (P < 0.05). Blood lactate remained unchanged up to approximately 40% VO2 max but increased 170% at approximately 60% VO2max. The responses in donkeys are similar to those of exercising horses except for the rapid decline in blood glucose observed during low-intensity exercise and the lower lactate levels at both the high-intensity exercise and the apparent anaerobic threshold.

Three pony geldings were given sodium bicarbonate orally in order to study the effect on blood pH and bicarbonate and to determine if frequency of dosing influences the response. In a preliminary study, it appeared that a carry-over effect might occur if the interval between dosing was only 2 days. The ponies received 2 doses of sodium bicarbonate (400 mg/kg) 7 days apart in trial one and then in trial two they received 2 doses of sodium bicarbonate 4 days apart. The sodium bicarbonate was mixed with 2 liters of warm water and given through a nasogastric tube on each trial day. Blood samples were taken before dosing, and every half hour after for five and a half hours. The blood was analyzed for pH and bicarbonate. There did not seem to be a carry-over effect due to sodium bicarbonate administration since there was little difference in the responses between the first and second doses of each trial.

Interest in mycotoxins and mycotoxicosis in humans and animals has greatly increased in recent years. Horses have long been considered very susceptible to molds. The signs, treatment, and prevention of several conditions, such as leukoencephalomalacia, aflatoxicosis, ergotism, fescue toxicity, slobbering disease, ryegrass staggers, and moldy sweet clover disease, are discussed.

1. Fecal excretion of calcium was examined in 122 individual ungulates representing 7 species of Equidae, 3 species of Tapiridae, 3 species of Rhinocerotidae, 2 species of Elephantidae, 2 species of Hippopotamidae, 12 species of Bovidae, 2 species of Cervidae, 3 species of Camellidae and 1 species of Giraffidae. 2. Animals were fed timothy hay, a low calcium diet or alfalfa hay, a high calcium diet. 3. In a few cases oat straw or prairie hay was used instead of timothy hay. 4. Samples of feces were obtained from individuals daily for 4 days following a 20 day dietary equilibration period. 5. Feces of equids, tapirs, rhinoceros and elephants had a lower calcium concentration and a lower Ca/P ratio than feces of ruminants when the animals were fed diets of equivalent calcium content. 6. The findings suggest that the non-ruminant ungulate equids, tapirs, rhinoceros and elephants absorb a larger proportion of dietary calcium than ruminants do.

Milk samples were obtained in early and/or late lactation from Przewalski horses, Hartmann's zebras, Grant's zebras, domestic horses, ponies and a mule mare made pregnant by embryo transfer. Samples were compared for their content of total solids, ash, calcium, phosphorus, magnesium, sodium, potassium, copper, zinc and iron. Milk from the Przewalski horses, Hartmann's zebra and the domestic horse had similar mineral composition and the content of minerals was higher in early than in late lactation. Milk from the domestic mule contained the lowest concentration of calcium, phosphorus and zinc but the highest concentration of magnesium, sodium and potassium. Milk from the Grant's zebras contained more sodium than potassium, unlike milk from Przewalski horses, Hartmann's zebras or domestic horses in which there was more potassium than sodium.

Twelve ponies were fed their total daily ration either as one large meal or divided into six small meals. Pre- and post-feeding behavior was recorded six times a day. Blood samples were taken for 30 min before and two hr after the meal. Plasma protein increased from 7.0 to a peak of 7.3 g/dl with small meals and from 7.3 to 8.1 g/dl with large meals, and returned to pre-feeding levels by 90 min post-feeding. Hematocrit rose from 33.3 to 34.1% with small meals and from 33.0 to 36.0% with large meals. These rapid and short-lived increases indicate a decrease in plasma volume. Plasma osmolality rose with feeding from 283 to 285 mosmoles/kg with small meals and from 281 to 288 mosmoles/kg with large meals. Water availability had no significant effect on blood changes. Digestibility and rate of passage were measured with chromic oxide, but there were no differences. Vocalizing (neighing) and walking occurred more often before than after feeding, while eating bedding and engaging in other oral behaviors were more frequent after feeding.

It appears that, in spite of many critics, the intake of soft drinks will continue to increase and that of milk will continue to decrease. The soft drinks contain no nutrients other than sugar, whereas milk contains many nutrients. Thus, the substitution of soft drinks for milk results in great decreases of minerals, protein, and vitamins but calcium is a nutrient of particular concern because milk is the major source of calcium. Therefore, the trend towards substituting soft drinks for milk should be reversed in order to ensure adequate intake of calcium and better nutrition.

Average gestation periods for bay, chestnut, dark bay, gray, and black Thoroughbred mares were compared. A total of 1359 gestation periods were used. A linear model including factors for age of mare, sex of foal, month and year of breeding, and sire effects was used in the analysis. Dam and sire coat-color combinations were also investigated in a similar manner. No significant differences in gestation length could be attributed to coat color of the mare of to dam and sire coat-color combinations. Heritability of gestation length was estimated to be 0.38. The results of this study strongly suggest that coat color is not associated with gestation length in Thoroughbred mares.

In order to determine if horses will increase their intake in response to caloric dilution, four pony geldings were fed ad lib a mixed grain diet either undiluted (3.4 Mcal/kg of digestible energy) or diluted (wt/wt) with 25% sawdust (2.6 Mcal/kg) or with 50% sawdust (1.7 Mcal/kg). The mean daily caloric intake was 17,457 kcal (3.4 Mcal diet), 17,546 kcal (2.6 Mcal diet) and 12,844 kcal (1.7 Mcal). The mean time spent eating was 246 (3.4 Mcal), 351 (2.6 Mcal), and 408 (1.7 Mcal) minutes/day. Meal size increased and meal frequency decreased with increasing dilution. The median long survivorships of intermeal intervals were 6.4 min (3.4 Mcal), 3.95 min (2.6 Mcal) and 4.91 min (1.7 Mcal). Ponies responded to caloric dilution by increasing the volume of intake to maintain caloric intake when the diet had 25% diluent. When the diet was diluted by 50%, intake was increased, but not at a rate adequate to maintain caloric intake. However, the ponies were able to maintain body weight.

Energy balance studies using indirect calorimetry were conducted with four mature equids ranging in weight from 125 to 856 kg. Each animal was fed three different levels of intake of the same diet. The amounts of digestible and metabolizable energy required for zero energy balance were determined by calculating regression equations for energy balance against energy intake. It was concluded that the maintenance requirements of equids vary linearly with body weight. No advantage was found for the use of weight for the comparison of equids within the range studied. The digestible energy (DE) requirement for equids confined to metabolism stalls was DE (kcal/d) = 975 + 21.28 X W where W equals body weight in kg. If a factor for activity similar to that suggested by the National Research Council was included, the requirement could be calculated by the equation: DE (kcal/d) = 1,375 + 30.0 X W.

Equine degenerative myeloencephalopathy (EDM) is a common spinal cord disease in the horse. The etiology of EDM currently is unknown. In other species, there are similarities in the clinical signs and neuropathological changes observed in EDM and in copper deficiency. The objective of this study was to determine if horses affected with EDM had low levels of plasma or liver copper. Plasma copper values were determined in 25 EDM affected horses and 35 normal horses. Liver copper levels were determined on 13 EDM affected horses and 22 normal horses. Plasma and liver copper values were not significantly lower in EDM affected horses than in control horses.

Plasma ascorbic acid (PAA) in normal Labrador Retriever dogs less than one year of age averaged 1.22 +/- 0.05 mg/dl (x +/- sem) and was significantly higher than the value of 0.89 +/- 0.03, for Labrador Retrievers two years of age and older. No significant diurnal variation in PAA was observed. Oral or intravenous administration of 0.5 or 1.0 g of ascorbic acid (AA) elevated PAA for less than 8 hours. Injection of ACTH caused a significant decline in PAA for the initial 2 days, with variable results thereafter. Labrador Retriever puppies fed a ration high in protein, energy and calcium developed the typical skeletal diseases of overnutrition, including hypertrophic osteodystrophy (HOD). The addition or oral AA (0.5 g twice daily) had no ameliorating effect on the skeletal lesions. Instead AA supplementation resulted in relatively higher serum calcium values which, presumably by enhanced hypercalcitoninism, decreased bone resorption. Thus, AA treatment of dogs with HOD is contraindicated, as it can only aggravate the osseous lesions of HOD. The decreased PAA reported in dogs with HOD is interpreted to be the result of stress from pain.

Consistency of exercise and diet are important in colic prevention. Water should be offered before and after feeding. Fast-growing foals suckling heavily lactating mares may overeat grain at weaning. Creep feeding to accustom the foal to eating grain and gradually increasing the grain intake after weaning are helpful in preventing colic in foals. Stallions may overeat grain when taken off pasture in hot weather. Feeding hay initially and grain later helps avoid colic in these stallions. Type-D Clostridium perfringens may cause enterotoxemia in foals. Corn should be fed in moderation. High-Mg diets, ingestion of sand, and pelleted feed have been associated with colic. Endoparasitism is the most important cause of colic in horses.

Epiphyseal and articular cartilages were examined in pony foals treated with intramuscular injections of either 0.5 mg dexamethasone per 100 kg bodyweight daily for 3, 8 or 11 months, or 5.0 mg per 100 kg for 11 months, and in horse foals treated with 5.0 mg per 100 kg for 20 weeks. The proximal femoral growth plates exhibited increased spatial separation between chondrocyte columns, narrowed zones of disorganized columnar and hypertrophic cartilage, abnormal penetration of hypertrophic cartilage by metaphyseal capillaries, retained cartilage in the spongiosa, distal terminal plate formation, transverse trabeculation, chondronecrosis and metaphyseal osteochondrosis dissecans. Destructive articular lesions were observed after 3 months of treatment with 0.5 mg per 100 kg bodyweight. Joint damage originated either at the joint surface or deep within the cartilage. Signs of surface deterioration included edema, fibrillation, enlargement of lacunae, pitting, shredding and erosions of cartilage. Inactivity of articular cartilage growth centers was common, with failure of epiphyseal capillaries to penetrate the lacunae in the calcified cartilage. Chondronecrosis adjacent to the calcification front was accompanied by cartilage ulceration and fracture. Intracartilaginous cysts and subchondral chondroid cysts were also observed. Healing responses included reparative chondrogenesis (focal cartilage hyperplasia), formation of fibrous or fibrocartilaginous "scars," subchondral osteopetrosis and epiphyseal marrow petrosis. Lactate dehydrogenase specific activities per chondrocyte, 35S uptake per cell and glycosaminoglycan contents of articular cartilages were all reduced 55% by 3 months of treatment. This inhibition of articular chondrocyte metabolism initiated cartilage degeneration. Surface destruction and osteochondrosis dissecans followed continued mechanical stress of compromised cartilage.

Many cases of enteroliths were reported in the nineteenth century but the number greatly decreased in the early twentieth century. However, in recent years the number of cases in certain parts of the United States such as California has greatly increased. The reasons for the increase are obscure. The intake of nitrogen, magnesium and phosphorus (the primary components of enteroliths) from water and food is likely to be a factor. Arabians may be more likely to develop enteroliths than horses of other breeds. A nidus such as a small stone is needed because a nidus has been found in every enterolith that has been examined. Further studies in which the effect of mineral intake and form of the mineral on enterolith formation are needed. Studies of enterolith formation in the past have all been retrospective. Models for the development of enteroliths are needed.

There have been several studies of biochemical changes in horses doing intense exercise such as Thoroughbred and Standardbred racehorses and in horses performing exercise over a long period of time such as endurance horses and three-day eventing horses, but we are not aware of studies with polo horses. Blood samples were taken from 18 polo horses at rest, immediately after playing 2 chukkers of indoor polo, and after a 15 minute rest period. Each horse was studied at 2 different games. The blood samples were analyzed for lactic acid, protein, sodium, potassium, chloride, calcium, phosphorus, HCO-3, PCO2, hemoglobin, packed cell volume, and pH. Samples taken immediately after playing polo had significant increases in lactic acid, protein, sodium, hemoglobin, packed cell volume, and pH, and significant decreases in chloride, calcium, PCO2, and HCO-3. Pulse and respiration were significantly increased. After a 15 minute rest period, there was a significant decrease in potassium. The HCO-3 was lower immediately after playing, but was above the resting value after 15 minutes. It was concluded that the changes after exercise are similar in some aspects to those reported for horses performing intense exercise such as racehorses, and in some aspects to those reported for horses performing prolonged exercise such as three-day event horses and endurance horses. Horses playing indoor polo develop a high plasma lactic acid, but with alkalemia, and could be used as a model to study this condition.

Absorption excretion and tissue distribution of stable Zn and 65Zn in mature ponies were studied in three experiments. In the first experiment, the metabolism of stable, dietary Zn and intravenously administered 65Zn was studied in three ponies in a 3 X 3 Latin square design. The ponies were fed a corn and beet pulp diet containing 35 mg Zn/kg or the same diet with 250 or 520 mg of supplemental Zn as ZnO. The ponies absorbed and retained more stable Zn when fed 250 mg of supplemental Zn that when fed the basal diet alone or the basal diet plus 520 mg of supplemental Zn. The ponies retained more 65Zn (percentage of dose) when fed the basal diet or the same diet with 250 mg of supplemental Zn. The intestinal tract was the major route of excretion of stable Zn and 65Zn. In the second experiment, the retention of an oral dose of 65Zn was studied in three ponies in a 3 X 3 Latin square design. The ponies were fed a beet pulp, corn starch and alfalfa meal diet containing 15 mg Zn/kg or the same diet with 240 or 480 mg of supplemental Zn as ZnO. The ponies retained a greater percentage of a dose of 65Zn when fed the basal diet or the basal diet plus 240 mg of supplemental Zn than when fed 480 mg of supplemental Zn. In the third experiment, four ponies fed a commercial pelleted diet containing 125 mg Zn/kg were given an intravenous dose of 65Zn. The ponies were killed 7 to 14 days after receiving the dose and tissues were counted for radioactivity. Parenchymatous organs such as liver, pancreas, kidney, heart and lung contained a greater percentage of 65Zn than did structural organs such as bone and muscle. The wall of the gastrointestinal tract contained more radioactivity than did the contents.

The effect of dietary aluminum on the absorption, retention and pathways of excretion of calcium, phosphorus, magnesium, zinc, iron and copper was studied in balance trials in mature ponies in a three by three latin square experiment. A basal diet consisting of one third each of oats, beet pulp and a commercial pelleted, complete horse ration and containing 336 ppm aluminum was supplemented with AlC1(3) . 6H2O. The middle and high level aluminum diets contained 1370 and 4500 ppm aluminum respectively. There was little difference in effect between the middle level aluminum and basal diets. The ponies were in negative phosphorus balance when fed the high level aluminum diet because phosphorus absorption was suppressed. Calcium absorption was unaffected by aluminum intake but the ponies were in negative calcium balance when fed the high aluminum diet due to the greater urinary excretion of calcium by the ponies. Presumably, calcium was excreted in urine because it was not utilized in the formation of bone crystal due to the lack of phosphate. Plasma calcium was elevated and plasma phosphorus was depressed when ponies were fed the high aluminum diet. Plasma hydroxyproline concentration was increased suggesting that bone turnover was increased due to aluminum effects on phosphorus and calcium metabolism. Magnesium, zinc, iron and copper metabolism were unaffected by aluminum intake.

The effect of level of protein intake on growth and calcium metabolism was studied in 24 foals. Starting at four months old, the foals were fed one of three diets containing all nutrients, with the exception of protein, at levels recommended by the United States National Research Council Subcommittee on Horse Nutrition for a 12 month period. The protein levels in the three diets were 9 per cent (low protein) 14 per cent (NRC recommended level) and 20 per cent (high protein). The foals fed the low protein diet were changed to the high protein diet after 140 days when they were nine months old. There were no significant differences in the rates of growth in weight, height, cannon circumference or in hoof growth and feed utilisation of the horses fed the 14 or the 20 per cent protein diets. However, growth, feed intake and feed utilisation by the foals fed the low (9 per cent) protein diet were significantly depressed. The average daily gains for the first 140 days for the 9, 14 and 20 per cent protein treatment groups were 64, 631 and 687 g in weight, 0.57, 0.83 and 0.87 mm in height and 0.04, 0.13 and 0.14 m in forecannon circumference, respectively. The average daily feed intakes for the 140 day period for the three groups were 2.7, 4.4 and 4.7 kg, respectively. After the change to the high protein diet the foals that had been fed the low protein diet maintained a higher rate of gain in bodyweight, height and cannon circumference, and utilised feed more efficiently than the other two groups throughout the second 140 days of the experiment.(ABSTRACT TRUNCATED AT 250 WORDS)

In a study of preferences for diets containing 1% to 20% sucrose over a bland diet, both female and male dogs preferred the diets containing sucrose over a bland diet, but female dogs had a significantly (P less than 0.05) greater preference for 1% sucrose than did males. Differences between sexes were not observed at the higher concentrations. Mean daily caloric intake was calculated for 12 bitches fed ad libitum during metestrus, estrus, and anestrus, as determined from metachrome-stained vaginal smears. Mean daily caloric intake was lowest during estrus (149 +/- 17 kcal/kg of body weight), was higher during metestrus (159 +/- 8 kcal/kg of body weight), and was highest (175 +/- 9 kcal/kg of body weight) during anestrus. Ovariohysterectomized bitches gained significantly (P less than 0.01) more weight (1.3 +/- 0.3 kg) in the first 10 days after surgery than did sham operated controls (0.3 +/- 0.1 kg). Food intake also was significantly greater ( less than 0.01) in the ovariohysterectomized bitches (1,708 kcal/day) than in the sham operated controls (1,423 kcal/day). Depth of subcutaneous fat in shoulder, rib, and rump areas of ovariohysterectomized bitches was not significantly different from that of intact bitches.

The effects of overfeeding, calcium-phosphorus imbalance, misuse of supplements and false advertising on equine nutrition are discussed. Overfeeding is known to cause disorders in several species but, although a similar relationship has been suggested on clinical evidence, no controlled trials on horses have been reported. It has also been suggested that overfeeding is a problem only for those horses with a genetic predisposition to skeletal problems. The importance of adequate calcium and phosphorus levels has been known for many years but severe cases of calcium deficiency still occur. Client education is important and should not be neglected. Excessive use of supplements containing high levels of trace minerals (eg, iodine and selenium) or fat soluble vitamins (eg, vitamin A and vitamin D) can be harmful. Some manufacturers advertise supplements in terms which may inadvertently or intentionally misrepresent their products. Supplements should, therefore, be selected carefully to ensure that they meet the particular requirements of the individual.

Recent studies on the digestive physiology of the horse are reviewed. It was suggested that the small intestine is the primary site of digestion and absorption of protein, soluble carbohydrates, most minerals, fats, fat soluble and water soluble vitamins. The large intestine is the primary site of fibre digestion and net water absorption. Significant amounts of phosphorus are also absorbed from the large intestine. Many factors such as rate of passage, processing of feeds, level of intake, work and maturity of plant may influence digestive ability.

The maze learning ability of six pony foals that had been weaned at birth was compared to that of six foals reared normally. The foals' learning ability was also compared to their mothers' learning ability at the same task; the correct turn in a single choice point maze. The maze learning test was conducted when the foals were 6 to 8 mo old and after the mothered foals had been weaned. There was no significant difference between the ability of orphaned (weaned at birth) and mothered foals in their ability to learn to turn left (6 +/- .7 and 5.1 +/- .1 trials, respectively) or to learn the reversal, to turn right (6.7 +/- .6 and 6.2 +/- .6 trials, respectively). The orphan foals spent significantly more time in the maze in their first exposure to it than the mothered foals (184 +/- 42 vs 55 +/- 15 s. Mann Whitney U = 7, P less than .05). The mothers of the foals (n = 11) learned to turn left as rapidly as the foals (5.9 +/- .7 trials), but they were slower to learn to turn right (9.8 +/- 1.4 vs 6.4 +/- .4 trials, Mann Whitney U = 33, P less than .05), indicating that the younger horses learned more rapidly. There was no correlation between the trials to criteria of the mare and those of her foal, but there was a significant negative correlation between rank in trials to criteria and age (r = -65, P less than .05) when data from the mare and foal trials were combined. The dominance hierarchy of the mares was determined using a paired feeding test in which two horses competed for one bucket of feed. Although there was no correlation between rank in the hierarchy and maze learning ability, there was a correlation between body weight and rank in the hierarchy (r = .7, P less than .05). This may indicate either that heavier horses are likely to be dominant or that horses high in dominance gain more weight. Maternal deprivation did not appear to seriously retard learning of a simple maze by foals, although the orphans moved more slowly initially. The lack of maternal influence on learning is also reflected in the lack of correlation between the mare's learning ability and that of her foal. Young horses appear to learn more rapidly than older horses.

Two giant pandas were used to assess the utilization of bamboo as a feedstuff. Three 1-week-long digestion trials were conducted during which feed intake and fecal output were recorded. Passage of digesta was measured from both fluid and particulate markers administered at feeding. Results indicate that the giant panda, although highly specialized for the consumption of bamboo, is a very inefficient digester of bamboo. The pandas consumed up to 6% of body weight in dry matter per day, with bamboo dry matter digestibility averaging less than 20%. Apparent digestion coefficients for the structural carbohydrates of bamboo (27% for hemicellulose and 8% for cellulose) indicate that, unlike most herbivores, pandas do not rely heavily on the microbial degradation of plant material to fulfill their nutritional requirements. Additionally, the passage of digesta through the gastrointestinal tract of the panda was extremely rapid, with complete clearance of markers in less than 12 hours. The giant panda seems to have specialized to a feed source high in plant fiber without extensive modification of the digestive tract by selectivity in feeding, effective mastication, ingestion of large quantities, digestion of cellular contents rather than cell walls and rapid fecal excretion of the undigested residue.

Preference trials were conducted with mature ponies. In Trial 1, oats were compared with oats plus sucrose. Four of six pony geldings selected oats plus sucrose, but one pony demonstrated a dislike for sucrose and one selected from the bucket on the right side regardless of content. Oats, maize, barley, rye and wheat were compared in Trial 2 using six mature pony mares. Oats were the preferred grain, with maize and barley ranking second and third respectively. Wheat and rye were the least preferred. Even though the ponies demonstrated preference, the total intake at a given meal was not greatly depressed when only the less palatable grains were fed. In Trial 3, pony mares selected a diet containing 20 per cent dried distillers' grain and 80 per cent of a basal mixed diet of maize, oats, wheat bran, soybean meal, limestone and molasses over 100 per cent basal mixed diet, but selected the basal diet over diets containing 20 per cent blood meal, beet pulp or meat and bone meal and 80 per cent basal diet. They did not differentiate against diets containing 20 per cent alfalfa meal or 10 or 5 per cent meat and bone meal when the diets were compared to the basal mixed diet.

In a study with 15 neonatal foals (5 per treatment group), foals were fed within 4 hours of birth as follows: 250 ml of colostrum, 250 ml of lyophilized serum reconstituted at 5 times the original concentration, or 250 ml of a mixture (1:1) of colostrum and lyophilized serum. Foal serum samples were tested for immunoglobulin (Ig)G concentration and titrated for anti-equine rhinovirus 1 and anti-equine influenza A1 and A2 antibodies at 0 and 24 hours after foals were born. Except in a foal which had suckled the dam before treatment, there was no evidence of IgG or specific viral antibodies in the samples taken at birth. There were no significant differences found in the serum IgG concentrations and antibody titers among the 3 treatment groups. Seemingly, IgG was absorbed efficiently from both serum and colostrum, so that the use of reconstituted lyophilized serum as a prophylactic measure of conferring passive immunity to a newborn foal deserves serious consideration.

The importance of olfaction in perception of flavor by flavor-validating dogs was studied. The flavor-validation technique is widely used by pet food manufacturers to determine if a given formula is perceived by dogs as having the flavor of a specific meat. Five Beagles were trained as flavor validators; 2 dogs were trained to select beef and 3 to select lamb from a panel of 4 meats. When the dogs had been trained to select the correct meat on 100% of the trials, they were made anosmic. Reversible peripheral anosmia was produced in the dogs by inflating a cuff on a surgically implanted tracheostomy tube. When the cuff was inflated, air entered the trachea via the tracheostomy tube, rather than via the nasal cavity, and the percentage of correct choices on the flavor-validating test fell to 62 +/- 14%. When the tracheostomy tubes were removed, performance returned to 100% correct. The nasal cavities of 3 dogs were infused with zinc sulfate to produce a more complete and longer-lasting anosmia. The percentage of correct choice on the flavor-validation test fell to 24 +/- 5%. These findings indicate that the flavor-validation test is based primarily on one sensory modality, that of olfaction; therefore, formulas selected by flavor-validating dogs may smell similar to the specific meat, but do not necessarily taste similar to that meat.

Changes in the mineral composition of mare milk during lactation were studied. Milk samples were obtained from five Thoroughbred mares one to three times weekly from the first to the eighth week of lactation and from two of the mares for an additional 8 wk. Samples averaging 500 mL were obtained after oxytocin was administered to the mares. Each sample was analyzed for total solids, ash, calcium, phosphorus, magnesium, sodium, potassium, copper and zinc. The concentration of all constituents except sodium and potassium decreased throughout lactation. The rates of decline of ash, calcium, phosphorus and magnesium concentration were similar, but the rates of decline of the other elements differed. Thus, the mineral composition of mare milk should be described in terms of the stage of lactation of the mare. The total solids and ash content of mare milk were 12 and 0.61% respectively, at the end of the first week of lactation, 10.5 and 0.45% at 4 wk, 10 and 0.38% at 8 wk and 10.2 and 0.32% at 16 wk. The calcium, phosphorus and magnesium concentrations at the end of the same periods were 1345, 943 and 118 micrograms/g of milk at 1 wk; 1070, 659 and 86 at 4 wk; 831, 574 and 58 at 8 wk and 700, 540 and 43 micrograms/g of milk at 16 wk. Copper and zinc concentrations were 0.85 and 3.1, 0.55 and 2.2, 0.29 and 1.9 and 0.28 and 1.8 microgram/g of milk at 1, 4, 8 and 16 wk, respectively.

The effects of copper intake on stable copper and 64Cu metabolism and on the excretory pathways of absorbed copper were examined in ponies. Bile and feces collected from two bile duct-cannulated ponies following an intravenous dose of 64Cu showed that bile was the main route of endogenous copper excretion. Stable copper and 64Cu metabolism were examined in three intact ponies fed dietary copper to provide 5.6, 16.6 and 25.7 mg Cu/100 kg body weight/day. The amount of copper excreted in urine was not influenced by dietary treatment. Stable copper absorption and 64Cu retention significantly increased when ponies were fed the low copper ration. A direct linear relationship was observed between 64Cu excretion in feces and copper intake. Isotope dilution methods and regression analyses of data from balance studies were used to estimate an obligatory copper loss in ponies of approximately 3.5 mg Cu/100 kg body weight per day. The estimated dietary copper requirement for maintenance of mature ponies was 3.5 ppm.