Quantity of Soft Pellets Produced by Caged Cottontails

Abstract

Production of the soft pellets that cottontails (Sylvilagus floridanus) normally reingest was measured with caged adults on commercial rabbit food. Soft pellets amounted to 30.4 percent of the total weight of both hard and soft pellets, a result similar to those reported for domestic rabbits (Orycto!agus cuniculus ). Production of soft food pellets (as opposed to hard fecal pellets) by caged adult cottontails on a diet of commercial rabbit food and water was measured during March 27-31 and June 20-23, 1967. All animals had been captive indoors in individual 16x 24x 13-inch wire cages for at least 18 weeks before the tests began. Production of food pellets was measured for six rabbits during each period. However, three animals were involved in both tests. Thus, nine animals were involved in the 12 determinations of food-pellet production. The animals were fitted with cardboard collars, 10 inches in diameter, which prohibited reingestion of soft pellets. Hard and soft pellets were collected from under the cages three times each day, beginning on the day after the collars had been fitted. Soft pellets were identified by their shape and their glutinous, textureless appearance. All pellets were dried at 65 C and weighed. Production of soft pellets was expressed as a percent of the total weight of both hard and soft pellets. Averages of production of soft food pellets by six cottontails during the March and June tests were 29.3 and 31.5 percent of total pellets, respectively. Since these averages were not significantly different, data for the two tests were combined; the aver1 A contribution from Illinois Federal Aid Project W-66-R, the Illinois Department of Conservation, the U. S. Bureau of Sport Fisheries and Wildlife, and the Illinois Natural History Survey, cooperating. The suggestions of G. C. Sanderson, W. R. Edwards, and Helen C. Schultz are acknowledged. 2 Present address: School of Forestry, University of Montana, Missoula, 59801. age production of food pellets for 12 determinations was 30.4 percent, with confidence limits between 26.2 and 34.6 percent (P < 0.05). In similar studies with domestic rabbits, Kulwich et al. (1953) and Huang et al. (1954) determined that 26.4 percent and 26.8 percent of the total pellets were food pellets, respectively. These averages are within the confidence limits mentioned above for cottontails. Six of these cottontails also participated in digestion trials during January, 1967, wherein the average digestibility of dry matter in Purina Rabbit Chow was 67 percent (range = 6271 percent). This was comparable to a coefficient of 68 percent obtained with domestic rabbits (Voris et al. 1940). Reingestion provides for a more complete digestion of the rabbit's food. Using the above digestion coefficient for cottontails and the information that food pellets amount to 30 percent of total pellets, it is calculated that with reingestion prohibited, the digestibility of Rabbit Chow would have been 53 rather than 67 percent.