Several studies have demonstrated the negative effects of clearcutting on terrestrial plethodontid salamander populations. However, none has experimentally compared clearcutting with multiple alternative timber-harvest methods. Using a randomized, replicated design, we compared the short-term effects (1-4 years after harvest) of clearcutting to effects of leavetree, group selection, and two shelterwood cuts on terrestrial salamanders in the southern Appalachian Mountains of Virginia and West Virginia (U.S.A.). Treatment plots were 2 ha each. We also compared salamander age class (percent juvenile), fecundity (percentage of females carrying eggs and average number of eggs per gravid female), size of gravid females, and species composition and diversity between treatments with canopy removal (cut) and those without canopy removal (uncut). All treatments with canopy removal had significantly fewer salamanders than the control treatment, but salamander abundances on alternative treatments with canopy removal did not differ significantly from salamander abundances on the clearcuts. There were no significant differences between cut and uncut treatments in the proportion of females that were gravid or in the average number of eggs in gravid females; however, gravid Plethodon cinereus females weighed more on the cut treatments and gravid Desmognathus ochrophaeus females weighed more on uncut treatments. There were no significant differences between cut and uncut treatments in the proportion of the sample that was juvenile, except in the largest species tested, P. glutinosus , which had a significantly higher proportion of juveniles in the uncut treatments. We conclude that initial declines in terrestrial plethodontid abundance caused by timber harvesting may be minimized across the landscape by concentrating high-intensity timber harvesting (clearcutting) in small areas (a few hectares in size).

Benthic core samples are used widely to assess availability of invertebrate prey to shorebirds. Accepted methodology includes sampling to a depth of 70 cm, although many shorebirds are morphologically incapable of acquiring prey at this depth. Given the time savings that would accrue from collecting smaller samples, we assessed the validity of sampling to a depth of 5 cm. We collected samples (n = 72) from moist-soil impoundments at 2 Atlantic coastal study sites being managed for migrant shorebirds. Each sample consisted of a IO-cm core that was split into 2 5-cm layers. Chironomids in the 5-cm surface layer accounted for 62% and 68% of within-sample abundance and biomass and explained 94% and 87% of the variation in among-sample chironomid abundance and biomass, respectively. Variance estimates among samples for abundance and biomass did not differ between 5-cm and 10-cm cores. We conclude that collecting benthic core samples at a depth of 5 cm is a valid sampling approach and recommend that this method be used in future studies of availability of shorebird foods.

Standard design of invertebrate activity traps limits their use to water depths that exceed the maximum foraging depth of most shorebirds. Assessment of nektonic invertebrate availability in shallow waters is desirable because shorebird diets may include these organisms. Thus, we used 1,022-ml polyethylene tissue culture flasks with a shallow (5-cm) profile to construct activity traps designed to assess nektonic invertebrate abundance in water depths less than or equal to 10 cm. We tested our design by collecting paired activity trap and benthic core samples during spring 1996 in moist-soil impoundments at Back Bay National Wildlife Refuge, Virginia. Seven of 24 taxa had disproportionate frequency of occurrence between samplers. Of these, 4 mobile taxa occurred with greater frequency in activity traps, whereas 3 benthic taxa occurred with greater frequency in core samples. Abundance was not correlated between sam piers for 5 of the 7 disproportionately sampled taxa, suggesting that the 2 samplers would provide dissimilar estimates of their availability to shorebirds. Core samples may fail to detect large, mobile organisms that may substantially contribute to the diet of some shorebirds, We recommend that shallow-water activity traps be used as a supplement to benthic core sampling in studies of shorebird food production.

Seven adult male white-tailed deer, Odocoileus virginianus, were maintained on experiment for I year to determine the effects of feed intake and time of year on serum concentrations of thyroxine (T4) and 3,5,3'-triiodothyronine (T3). Food intake was either ad libitum or 75 percent ad libitum. Blood samples were taken every 28 days. Both serum T3 and T4 were highest from May-August and lowest in November. Changes in food consumption lagged behind changes in T3 and T4. T4 values of restricted deer from November-February were lower (P < 0.01) than corresponding values for ad libitum animals, whereas T3 values of restricted deer were significantly depressed (P < 0.01) throughout the entire year.

Puffed grouse (Bonasa umbellus) in the southeastern United States commonly eat evergreen leaves during winter. Despite their abundance, these leaves rarely make up >50% of the diet. We fed diets containing 20 and 40% mountain laurel (ML) (Kalmia latifolia) and Christmas hollyfern (CHF) (Polystichum acrostichoides) to captive ruffed grouse to determine the bird's ability to exist on these forages and to investigate detoxification of secondary plant compounds. Grouse consuming diets with 20% of test forages performed similar to grouse eating a control diet. Diets with 40% of the test forages caused reduced intake and birds consuming the CHF diet were unable to maintain body mass. Conjugate-based detoxification systems were stimulated by both test forages, although detoxification strategies varied between forages and levels of forage in the diet. Although grouse appear unable to exist solely on evergreen leaves, these forages probably contribute to ruffed grouse winter survival by remaining available during snow accumulation and by decreasing foraging times due to high intake rates.

Winter diets of ruffed grouse (Bonasa umbellus) and other galliformes are high in tannins. We fed quebracho, a condensed tannin, to ruffed grouse and found no effect on dry matter intake or body mass at levels up to 6% of the diet. However, a high-fiber diet with 8% quebracho resulted in reduced dry matter intake and body mass loss. Grouse could not tolerate a diet with 8% tannic acid, a hydrolyzable tannin, which caused a large reduction in dry matter intake and body mass. Northern bobwhite (Colinus virginianus) and ruffed grouse responded to dietary quebracho tannin by increasing the proportion of digesta that was excreted from the ceca. In the northern bobwhite, 59%-76% of the tannin recovered from the feces was in cecal feces. There was no difference in average passage rates of liquid and fiber digesta, although variation was high in tannin-fed birds. The role of the ceca in handling tannin requires further investigation.

One hypothesis to explain low densities of ruffed grouse (Bonasa umbellus) in the southeastern United States is that available winter forages in the Southeast require more time to harvest than forages eaten in the central portions of the species' range, where grouse densities are greater. Longer foraging times could increase mortality rates through greater predation risk and higher energy expenditure. To test this hypothesis, we conducted trials with captive ruffed grouse to determine their maximum instantaneous rates of intake of various forages and used the results to estimate minimum foraging times for southeastern ruffed grouse consuming an average winter diet. Grouse in the Southeast must forage for > 100 min to meet their energy demands. Ruffed grouse in the central portion of the range rely heavily on aspen (Populus sp.) buds during the winter and can consume the same amount of metabolizable energy in 30–50 min. Thus, we present evidence that ruffed grouse in the southeastern United States must forage for longer periods to meet daily energy demands and therefore may experience higher winter mortality rates.

Sediment from Killarney Lake, Idaho was added to the diet of captive northern bobwhites (Colinus virginianus) to determine absorption of Pb from contaminated sediment. The sediment, containing 4,500 μg g−1 Pb dry weight (d.w.), was added to ground poultry ration at 8% dry matter intake (DMI) for 21 days. Concentrations of Pb in blood, liver, and kidneys of each bobwhite were determined and compared to concentrations in untreated control bobwhites. Treated bobwhites showed no significant decline (P>0.05) in food intake or body mass over time. In 90% of treated bobwhites, blood Pb concentrations reached levels associated with clinical Pb poisoning (>0.8 μg g−1 wet weight, w.w.); and all treated bob-whites had elevated liver and kidney Pb concentrations. It was shown that tissue Pb accumulation can occur from ingestion of Pb-contaminated sediment.

Journal Article Comments on Estimating Total Body Lipids from Measures of Lean Mass Get access John M. Morton, John M. Morton Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 Search for other works by this author on: Oxford Academic Google Scholar Roy L. Kirkpatrick, Roy L. Kirkpatrick Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 Search for other works by this author on: Oxford Academic Google Scholar Eric P. Smith Eric P. Smith Department of Statistics, Virginia Polytechnic Institute and State University, Blacksburg, VA 2406 Search for other works by this author on: Oxford Academic Google Scholar The Condor, Volume 93, Issue 2, 1 May 1991, Pages 463–465, https://doi.org/10.2307/1368970 Published: 01 May 1991 Article history Received: 15 October 1990 Accepted: 07 January 1991 Published: 01 May 1991

Captive female black bears were immobilized and sampled at approximately 10-day intervals from September to March during 2 years (six bears/year) in Virginia. Ten of 12 bears hibernated for an average of 92 days. Rectal temperature declined (P < 0.001) during hibernation to as low as 34.6°C. Average loss in mass for hibernators was 260 g/day and represented 23.1% of peak body mass. Urea : creatinine ratios differed (P < 0.01) after hibernation between hibernators and active bears, declining to 7.2 ± 0.3 (X̄ ± SE; 84 samples) during hibernation. Serum concentrations of total protein, urea nitrogen, creatinine, and bilirubin also differed (P < 0.01) between groups after onset of hibernation. Urea : creatinine ratio was a good indicator of the hibernating state, but the sensitivity of serum-urea concentrations to diet suggests careful use of this ratio as a field index of hibernation.

We used scan sampling techniques to quantify behavior and energy expenditure of American black ducks (Anas rubripes) at Chincoteague National Wildlife Refuge (NWR), Virginia, during the winters of 1985-86 and 1986-87. Time, tide, and habitat influenced black duck behaviors; therefore, diurnal time budgets were constructed by distributing scans over a time-tide matrix within refuge pool, saltmarsh, and tidal-water habitats. Black ducks observed during the day fed least and rested most when in refuge pools, and fed most and rested least when in tidal waters. Estimated daily energy expenditure (DEE) of American black ducks wintering at Chincoteague NWR was similar to values reported in Maine at a given temperature. Although DEE of undisturbed and disturbed flocks were similar, black ducks curtailed feeding and increased time spent in alert and locomotion behaviors in response to disturbance. We suggest that human disturbance of wintering black ducks impairs their physiological condition, thereby reducing winter survival and/or nutrient reserves carried to the breeding grounds. J. WILDL. MANAGE. 53(2):401-410 The decline in populations of American black ducks over the past 3 decades (Steiner 1984) has prompted behavioral research of wintering black ducks. Albright et al. (1983) investigated behavioral responses of wintering black ducks in Maine to temperature, wind chill, and availability of ice-free foraging habitat. Black ducks rested more and fed less with decreasing temperature and increasing ice, even as total DEE increased due to the demands of thermoregulation. Albright et al. (1983) suggested that black ducks in northern wintering areas experience extreme food shortages and that there was evidence of a physiological set-point below which it is more advantageous to rely on energy reserves than to expend energy searching for food. Hickey and Titman (1983) employed scan sampling to study black ducks wintering on Prince Edward Island; ducks fed less and rested more with increased wind chill and tide level. More information is needed to determine the amount of time black ducks spend in various habitats and to measure nocturnal activity (Hickey and Titman 1983). Brodsky and Weatherhead (1985a,b) demonstrated that local food availability can determine black duck behavioral responses to low temperatures in Canada. Brodsky and Weatherhead (1984) also studied the posturing of black ducks while resting and roosting as a mechanism for reducing thermoregulatory costs. They suggested that the management of energy expenditure is as much a consideration as management of energy intake by black ducks. We used the time-budget approach to quantify behavior and energy expenditure of black ducks wintering on, and in the vicinity of, Chincoteague NWR, Virginia. Objectives were to estimate time and energy expenditure within different habitats, identify environmental factors that influence behavioral response, and contrast black duck allocation of time and energy resources in tidal Virginia with results of studies conducted at higher latitudes. We thank M. R. Vaughan and D. R. Stauffer for suggestions and criticisms during the study and D. W. Howerter for field assistance. This study was supported by the U.S. Fish and Wildlife Service and the Department of Fisheries and Wildlife Sciences, Virginia Polytechnic Institute and State University.

Diet quality, condition indices, and blood chemistry characteristics were determined for a black bear (Ursus americanus) population in the Great Dismal Swamp on the Atlantic Coastal Plain. Blood samples from 122 captures of 99 bears were analyzed. Seasonal shifts in diet composition were similar to previously reported findings for black bear food habits in the southeastern United States. Three major levels of diet quality were observed in terms of crude fiber, fat, and protein. Spring diets were high in protein but moderate in crude fiber. Condition indices (body weight, length/weight ratios) peaked in spring and late fall and were low during summer. Several blood characteristics (e.g., total protein, albumin, hematocrit, hemoglobin, and red blood cells) showed a similar annual rhythm (P < 0.01) for both sexes. Serum creatinine concentrations also varied seasonally (P < 0.001), with a peak during denning and high levels in spring and late fall, perhaps resulting from transition from and to hibernation. Urea/creatinine ratio was not a good indicator of the hibernating state, as 39 of 120 (32.5%) trapped bears had urea/creatinine ratios ≤ 10. Creatinine and total protein were the best indicators of the hibernating state. Albumin, hematocrit, hemoglobin, and red blood cells were the best indicators of condition during active stages, as correlations of condition indices and blood variables indicated significant (P < 0.1) associations between body condition and albumin, hematocrit, hemoglobin, and red blood cells. Nine blood variables varied with age (P < 0.1). Multivariate analysis of variance and discriminant function analysis using blood variables failed to reject the hypothesis that bears cycle through four metabolic stages throughout the year. Our results showed that metabolic shifts were tied to concomitant seasonal changes in diet quality, diet composition, and body condition. Comparison of our work with other published data on bear biology suggests that seasonal changes in bear physiology may be due partly to an endogenous rhythm.

Food habits, diet quality, carcass fat, and reproductive condition of 63 Ruffed Grouse (Bonasa umbellus) collected in southwestern Virginia during March and April 1982-1984 were determined. Acorns (Quercus spp.) made up 60% of the crop contents of 22 grouse collected in 1982, the spring following a year of high acorn production. Leaves of herbaceous plants and buds of deciduous plants were the primary forages of 41 grouse collected in spring 1983 and 1984. Metabolizable energy estimates for grouse diets ranged from 50-64% and 2.30-2.68 kcal/g of dry matter, and dietary protein ranged from 14.6-17.4%. Fat levels of grouse were greater (P < 0.05) in March than April, and females had more (P < 0.05) fat than males. Fat levels did not differ (P > 0.05) among years; however, fat levels of females tended to be greatest in 1982 when acorns were the primary food used. Mean ovary and oviduct weights and paired testes weights increased (P < 0.05) from March to April suggesting that concurrent declines in fat reserves were related to increased reproductive activity.

The Elizabeth River in southeastern Virginia is a major tributary emptying into the James River near its confluence with the Chesapeake Bay. Numerous studies of the river sediment, water, and aquatic life have indicated high concentrations of environmental pollutants. Among these toxic substances, polynuclear aromatic hydrocarbons have become a major concern with especially high concentrations reported in the Southern Branch of the river. Although several studies have attempted to elucidate the effects of these contaminants on aquatic life within the river, no major studies have been conducted on contaminant influences on the mammalian fauna of the area. This presentation discusses an analysis of muskrat populations in the Elizabeth River for bioindicators of exposure to toxic chemicals in that environment. The Nansemond River, which is located 7 miles west of the Elizabeth River and has similar physical characteristics but lacks the contaminant exposure, serves as a control. Sixty muskrats were live trapped and are being analyzed for a variety of physical and chemical indicators of exposure to and adverse effects from these contaminants. The research includes an analysis of pentobarbital induced sleep time, comparison of blood characteristics, comparison of carcass and liver weights, determination of reproductive status and population densities, detectionmore » of DNA adducts in liver tissue and PAH metabolites in bile, and the histological examination of liver and kidney tissue.« less

Percent wing fat (WF), gizzard fat weight (GFW), and body weight (BW) were tested as indices of percent carcass fat (CF) and a lipid index (LI) in ruffed grouse (Bonasa umbellus). Gizzard fat weight was related (P < 0.0001) to the natural log of both CF and LI. Prediction equations were developed for estimating CF and LI from GFW. These relationships were not affected by sex or season of collection. Fat content of the distal half of the wing was correlated (P < 0.05) with CF and LI, but relationships differed (P < 0.05) by sex in the spring. Correlation coefficients for the fall season were low (r = 0.55-0.58). Relationships between BW and CF were not consistent for sexes or seasons. Percent carcass fat and LI of 118 ruffed grouse collected in North Carolina during the fall and winter were predicted from GFW. Percent carcass fat and LI were greater (P = 0.036) in females than males and tended to be greatest for both sexes in December. J. WILDL. MANAGE. 51(1):173-177 Norman and Kirkpatrick (1981) reported that wing fat was correlated with CF in ruffed grouse collected in Virginia. However, correlations were weaker in the spring and summer than in the fall and winter, indicating potential problems with the technique. An advantage of using WF as an index of condition is that wings can be easily collected from hunters for analysis. Weight of the fat attached to the gizzard of ruffed grouse also may be a useful index of CF. Abdominal or visceral fat deposits were strongly correlated with body fat (BF) in waterfowl (Woodall 1978, Bailey 1979, Chappell and Titman 1983, Thomas et al. 1983). Dowell and Warren (1982) used GFW as a nutritional index for ring-necked pheasants (Phasianus colchicus). Gizzards and attached fat of ruffed grouse also could be obtained from hunters. The objectives of the present study were to: (1) determine the reliability of WF, GF, and BW as indices of CF in ruffed grouse and (2) estimate the CF levels of ruffed grouse collected in North Carolina during fall and winter. This research was supported by the John Lee Pratt Anim. Nutr. Fellowship Prog. at Virginia Polytechnic Inst. and State Univ. (VPI&SU), the Dep. Fish. and Wildl. Sci. at VPI&SU, and the Natl. Rifle Assoc. Grants-In-Aid Prog. D. Beck coordinated collections of ruffed grouse gizzards in N.C. S. L. MacPherson and W. Morehead assisted in the laboratory. P. F. Scanlon, J. D. Fraser, M. R. Vaughan, and K. E. Webb, Jr. reviewed drafts of the manuscript. METHODS Sixty-two ruffed grouse were collected in southwestern Virginia during March and April 1982-84. Twenty additional grouse were collected between 1 November and 1 January from 1981 to 1984 in Virginia (N = 8) and New York (N = 12). Whole body weights were measured after removing crop contents. Grouse were completely plucked, and lower legs were removed at the tibio-tarsus-tarsometatarsus junction. Reproductive and digestive tracts were removed, but mesentery fat was stripped from the organs and replaced in the body cavity. Gizzard Fat Weight and Index Fat adhering to the gizzard was weighed after lightly blotting surface moisture, and the fat was returned to the body cavity. The empty gizzard was weighed, and a gizzard fat index (GFI) was calculated by dividing the weight of the fat attached to the gizzard by the gizzard weight.

The percent metabolizable energy (ME) in 13 of 14 diets fed to captive ruffed grouse (Bonasa umbellus) in metabolism trials was highly related (P = 0.0001, R2 = 0.88) to the percent neutral detergent solubles (NDS) minus total phenol content of the diets. A regression equation based on these data provided good prediction of the ME of 8 diets fed to grouse in a 2nd set of metabolism trials. The ME of diets containing acorn meat was underestimated by the prediction equation; therefore, a multiple regression equation based on NDS minus phenols and percent acorn meat was developed to predict the ME of diets containing acorn meat. The effects of storage and drying treatments of forages on measured NDS, total phenols, and predicted ME levels were determined. Oven-drying fresh, leafy forages and oven-drying after frozen storage consistently resulted in lower levels of NDS and total phenols than freeze-drying fresh forages. Effects on predicted ME were small because changes in NDS and total phenol levels are offsetting to a large extent in the prediction equation. J. WILDL. MANAGE. 51(3):560-567 Ruffed grouse food habits are well documented (Brown 1946, Bump et al. 1947, Korschgen 1966, Phillips 1967, Woehr and Chambers 1975, Stafford and Dimmick 1979, Seehorn et al. 1981), but relationships between food habits and diet quality are largely unknown. Little information is available on the ME of grouse forages or diets. This is due in part to a lack of accurate and efficient methods for measuring the ME in the natural diet of ruffed grouse. Studying all forages individually in conventional metabolism trials is impractical because of the varied diet of grouse. In addition, 1-time measurements of ME from metabolism trials does not account for variation among seasons, years, or locations. Predicting the ME of forages of ruffed grouse from forage chemical composition is a promising alternative method because large numbers of forages could be studied much more efficiently and crop contents could be chemically analyzed, thereby eliminating the bias between hand-picked forages and forages selected by wild birds. The Van Soest method of forage chemical analysis (Goering and Van Soest 1970) has proven to be reliable for predicting forage digestion in both ruminant and monogastric mammals (Van Soest 1967, Mould and Robbins 1982, Servello et al. 1983, MacPherson et al. 1985) and may be useful for avian species also. However, high levels of phenolic compounds in forages may complicate prediction of forage digestion when using the Van Soest analysis. Phenols are extracted as part of the theoretically highly digestible neutral detergent soluble fraction; i.e., primarily soluble carbohydrate, protein, and fat. However, they have little or no nutritional value and also may interfere with digestion and absorption (McLeod 1974; Mould and Robbins 1981a,b, 1982). Also, storage and drying treatments can influence measured chemical constituents of forages, especially highly reactive phenols (Mould and Robbins 1981a). The objectives of the present study were: (1) to determine the relationship between forage chemical composition (as measured by the Van Soest method) and forage ME for ruffed grouse, (2) to develop a predictive equation for estimating ME based upon this relationship, (3) to determine the influence of phenolic compounds on prediction of forage ME, and (4) to determine the effects of a number of commonly used storage and drying treatments on NDS and phenol levels and therefore on prediction of forage ME. We thank W. B. Morehead, S. L. MacPherson, and K. B. Preli for assistance with metabolism trials and laboratory analyses. This research was supported in part by the Natl. Rifle Assoc. and the Dep. Fish. and Wildl. Sci., Virginia Polytechnic Inst. and State Univ. The senior author was supported by a John Lee Pratt Anim. Nutr. Fellowship.

Two experiments were conducted to determine the relative influence of photoperiod and nutrition on reproduction and related characteristics of pine voles (Microtus pinetorum). In a laboratory experiment, adult voles fed a rabbit chow diet supplemented with fresh apples had more body fat and males had heavier testes than those fed only rabbit chow. Voles of both sexes on a 14L:I OD photoperiod had heavier reproductive organs than those on a naturally declining photoperiod. In a field study, the presence of apples as a food source during the autumn had little effect on vole body fat content. However, more females were pregnant and males had heavier testes and seminal vesicles and higher spermatoza counts in areas with apples. We conclude that both photoperiod and nutrition influence the extent of late autumn and winter breeding of pine voles and that their effects are additive. INTRODUCTION The pine vole, a pest that causes economic losses in apple orchards along the eastern seaboard (Byers et al., 1976), has a longer breeding season and higher reproductive rates in maintained orchards than in abandoned orhards (Noffsinger, 1976; Cengel et al., 1978). Cengel et al. (1978) hypothesized these differences arose from the higher nutritional quality of forage and greater availability of fallen apples in maintained orchards. Lochmiller (1980) demonstrated that forage biomass was higher in maintained orchards, and differences in habitat or supplemental feeding have been shown to cause higher rates of reproduction and growth in other microtine rodents (Krebs and DeLong, 1965; Andrzejewski, 1975; Cole and Batzli, 1978, 1979). There are few studies of the influence of photoperiod on reproduction in pine voles. Geyer and Rogers (1979) reported that exposure to low light intensity reduced the number of litters and number of young per litter in pine voles. However, Lepri and Noden (1984) reported that reproductive function was independent of photoperiod in adult male pine voles in North Carolina. Short photoperiod has been shown to reduce litter size, number of litters or reproductive organ weights in Microtus agrestis (Baker and Ransom, 1932a,b), M. pennsylvanicus (Imel and Amann, 1979) and M. californicus (Nelson et al., 1983). The additive effects of photoperiod and nutrition have been demonstrated in M. montanus (Pinter and Negus, 1965) and M. californicus (Nelson et al., 1983). In the present study, two experiments were conducted to determine the relative influence of nutrition and photoperiod on reproduction in pine voles. MATERIALS AND METHODS Laboratory experiment. -The objective of this experiment was to test the influence of nutrition and photoperiod on reproductive activity in adult pine voles under controlled conditions. The experiment was conducted in an unheated, metal frame building with translucent skylight panels. Three to 5 cm of soil were placed in the bottom of four concrete troughs (originally constructed as fish raceways) inside the building. Troughs were divided into 12 sections of 2.2 by 1.1 m each. Adult pine voles were trapped from an orchard near Roanoke, Virginia, in late July and immediately placed in the troughs. On 15 September, groups of two male and five female voles were formed at random and placed in each of the 12 sections. Half of these groups was fed ground Purina Rabbit Chow (C) ad lib. The other half was fed ad lib amounts of both sliced apple and ground rabbit chow (A). The six groups on each diet