Abstract:
The present invention provides an animal litter which has as its major ingredient peanut hulls, and as an odor suppressor, sodium bicarbonate.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     Animal litter prepared for household pets and laboratory animals has been marketed for several years and has found wide acceptance. The size of the available market is considerable when it is considered that the potential market for cat litter alone in the United States is about 1.3 pounds of litter per capita of human population annually. 
     As is to be appreciated, more leeway can exist in the type of material acceptable for laboratory animals and household pets when the litter is of the non-contact type, whereas strict controls must be maintained with direct contact litter. With non-contact litter, absorbent properties, odor and dust control, price and ease of litter disposal are of prime importance. In addition to these factors, other things such as lack of nutritive value or attractiveness as feed, and absence of skin irritant properties are important in contact litters. Further, it is important to consider the cost of raw materials, basic absorbent properties of the litter in relation to weight, resource allocation such as whether or not the raw materials have to be produced, as in the case of alfalfa, or mined and treated as in the case of clay. 
     2. Prior Art 
     Generally known litter compositions are either compositions containing large amounts of clay or natural grass compositions containing a natural grass such as alfalfa. Alfalfa containing compositions contain compressed alfalfa for absorbing liquid. The alfalfa contains chlorophyll which also acts as an odor suppressant. The patent ot Bickoff et al. U.S. Pat. No. 3,747,564 shows one such composition. The McFadden U.S. Pat. No. 3,286,691 discloses an alfalfa containing composition which may also contain a clay such as bentonite. One particular method for preparing a clay-alfalfa litter composition is disclosed in U.S. Pat. No. 3,789,979 of Brewer. While the alfalfa or grass contains chlorophyll which acts as an odor suppressant, the alfalfa has a strong odor itself, particularly when wet, and may smell like &#34;silage&#34; which renders its use unacceptable for many applications, particularly in confined areas, such as apartments and the like. 
     The use of many conventional litter materials is somewhat objectionable in that they fail to sufficiently suppress odors caused by the liquid waste materials or they possess distinct odors of their own. As noted, one method suggested by the prior art to reduce this problem is by the addition of an odor controlling agent such as chlorophyll. 
     U.S. Pat. No. 3,735,734 describes an odor suppressing litter material which contains a combination of a synthetic chlorophyll containing compound and an odor inhibiting additive such as sodium dihydrogen phosphate. In addition, this patent describes the use of a large number of substances commonly used as litter materials for animals. Such substances include peanut hulls. However, as further noted in the patent, it has been found that peanut hulls are too light and are easily kicked out of an animal commode or tracked about the premises by the animal thus rendering them unsatisfactory. The Peanut Journal and Nut World Volume XIV, No. 4., February 1975, pages 15 and 16 also refers to the use of peanut hulls as a poultry litter and proposed animal litter. 
     SUMMARY OF THE INVENTION 
     One object of this invention is to provide an animal litter which comprises as its chief ingredient a by-product which must otherwise be disposed of in a manner to meet existing environmental regulations. 
     Another object of the invention is to provide a litter that has properties superior to existing animal litter for use with household pets, especially cats, and for a number of laboratory animals. 
     A still further object of the invention is to provide a litter which controls odor and thereby has an extended life. 
     These and other objects as hereinafter become apparent are achieved by an animal litter which comprises as the chief ingredient compressed peanut hulls. 
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Attempts have hitherto been made to use peanut hulls as an animal litter. These attempts have proven to be unsatisfactory as indicated in U.S. Pat. No. 3,735,734 wherein it is stated that peanut hulls are too light and are easily kicked out of an animal commode or tracked about the premises by the animal. 
     It has now been discovered that by grinding peanut hulls by conventional techniques, such as by a hammermill, to a size which will pass a screen mesh of between 1/16 and 1/4 inch, preferably about 5/32 of an inch and then pelletizing the thus ground hulls an absorbent pelleted animal litter is produced having a sufficient density so as not be be readily displaced from the litter containing container by the animal. The litter also has sufficient density so as to avoid any significant tracking problem. 
     The ground peanut hulls may be pelletized using conventional techniques for pelleting animal feeds. Conventional pelleting aids may be used, such as clay, with bentonite clay being particularly preferred. The amount of pelleting aid used is about 1 to 5%. Preferably, the pelleting aid used constitutes about 2% of the litter. The pellets formed by using these techniques are obtained in a convenient size for direct use as an animal litter by cutting the pellet into lengths of about from 1/8 inch to about 1/2 inch. The size of the pellet will of course depend upon the size of the animal which will use the litter, the larger the aniaml the larger the pellet size. A particularly preferred size is about 1/8 by 1/8 inch. 
     In addition to the pelleting aid it is preferred to add an odor suppressor to extend the useful life of the litter. Other substances may also be added as filler, such as a fibrous substance, which includes grass. However, the amount of peanut hulls used must be between from about 60, preferably from about 80 and most preferably from about 90 to 98% to obtain the objects of the invention. The peanut hulls are mixed with the desired additives of proper size and the mixture pelletized. 
     Basic substances such as sodium bicarbonate, calcium carbonate, tri sodium phosphate, sodium carbonate may be used in an amount which is effective to suppress odors and extend the useful life of the litter and are thus effective odor suppressors. Sodium bicarbonate is particularly preferred as an odor suppressor. The amount of the above odor suppressor contained in the litter composition should be from about 0.5 to 8%, preferably from 1-6% based on odor suppression and water absorption. In addition, known odor suppressors may be added such as natural grasses and the like. Thus the filler which may replace a portion of the peanut hulls may be a natural grass such as alfalfa thereby obviating the need for an additional odor suppressor. However, in no case should the amount of natural grass contained in the composition be sufficient to produce a &#34;silage&#34; odor in the composition. 
    
    
     EXAMPLE I 
     Three animal litter formulations were prepared as follows: finely ground peanut hulls (hammermilled through a 5/32 inch screen) were mixed with the ingredients as indicated below. Each formula was mixed well in a horizontal ribbon blender and then pelleted through a California Pellet Mill (Mod. 50248, 30 hp). A die size of 5/32 inch was used and pellets of appropriate size for use directly as an animal litter were obtained. 
     
         ______________________________________          Formula   Formula   FormulaIngredient     No. 1     No. 2     No. 3______________________________________Peanut hulls wt.%          83        73        81Alfalfa meal wt.%          15        25        15Bentonite clay, wt.%          2         2         2Corn oil wt.%  0         0         2______________________________________ 
    
     As can be seen from these formulations the peanut hulls are used in a range of from about 70 to 85% and the alfalfa in a range of about 15 to 25%. 
     The effectiveness of these animal litter formulations were evaluated by both laboratory tests and actual use. In the laboratory tests formulation No. 1 was compared to alfalfa and clay pellets to determine moisture absorption with the result that formula 1 absorbed 288% moisture, alfalfa pellets 402% and clay 126% indicating the high moisture absorption of formulation No. 1 without the objectionably strong alfalfa odor present in the pure alfalfa pellets. 
     The formulations (No. 1, 2 and 3) were also compared to the commercially available litters Sani-Cel which is ground corn cobs manufactured by Paxton Processing Corp., Paxton, Illinois, and Ab-Sorb-Dri manufactured by Ab-Dri Inc., Garfield, New Jersey which is hardwood shavings. The results are shown in table I. 
     
                                           TABLE I__________________________________________________________________________Comparisons Among Experimental Peanut Hull Beddings, Sani-Cel andAb-Sorb-Dri__________________________________________________________________________Characteristic        Formula No. 1                  Formula No. 2                           Formula No. 3                                    Sani-Cel                                           Ab-Sorb-Dri__________________________________________________________________________Quantity Used (g)Contact Use (GuineaPigs).sup.1   800       800      800      440    250Non-contact use(Cats)        454       454      454      --     454Absorption (Urine)Contact Use: Guinea        Good (Caking)                  Good (Caking)                           Good (Little                                    Poor   PoorPigs 2/cage (20&#34;×         Caking)16&#34;×81/2&#34; high)Non-contact Use:        Fair-Good Fair-Good                           Fair-Good                                    Poor   PoorCats 1/cage (18&#34;×24&#34;×30&#34;)Fining and Dust.sup.2Contact Use: Guinea        Mostly Pul-                  Some Pul-                           Little Pul-                                    Some Pul-                                           None Pul-Pigs 2/cage (20&#34;×16&#34;        verized   verized  verized  verized                                           verized×30&#34;)Non-contact Use:        Pellets   Pellets  PelletsCats 1/cage (18&#34;        Retained  Retained Retained Very×24&#34;×30&#34;)        Some Shape                  Little Shape                           Little Shape                                     --     --StainingAnimals      None      None     None     Some (Pro-                                           None                                    bably from                                    Manure)Caging       None      None     None            NoneAttractivenessas Feed      Little    Little   Little   Little None        (Initially        Curiosity Item)__________________________________________________________________________ .sup.1 All beddings in equal volume to cover cage bottom for 51/2 days. .sup.2 Experimental pellets not usual size; ave. 1/2&#34; long. Therefore, durability test not conducted. 
    
     As can be seen from Table I, the litters of the present invention were found overall superior compared to Sani-Cel and Ab-Sorb-Dri. 
     EXAMPLE 2 
     The procedure of Example 1 was followed using 98% ground peanut hulls and 2% bentonite clay to form formulation No. 4. Comparisons were made with this formulation and Sani-Cel, Ab-Sorb-Dri and wood shavings. The results are reported in Table II. 
     
                                           TABLE II__________________________________________________________________________Comparisons Among Experimental Peanut Hull Bedding, Sani-Cel, Ab-Sorb-Driand Wood Shavings__________________________________________________________________________Characteristic  Formulation No. 4                       Sani-Cel    Ab-Sorb-Dri   Wood__________________________________________________________________________                                                 ShavingsQuantity Used (g)Non-contact (cats).sup.1           1362,671                1362,671      227Contact use (guinea pigs).sup.2            850,425    450,225      300,150AbsorptionNon-contact (1 cat/18&#34;×24&#34;×30&#34; high cage)           Good         --         Good-Fair     Fair-GoodContact (2 guinea pigs/20&#34;×16&#34;×81/2&#34; high cage)           Good        Fair-Good   Good-Fair      --Odor ControlNon-contact     Good         --         Good-Fair     Good-FairContact         Good        Good-Fair   Good-Fair      --Fining and DustNon-contact     No dust initially,                        --         Slightly dusty initially.                                                 Slightly           pellets loose shape                   dusty init-           as moisture absorbed.                 ially.Contact         Pellets crumble from                       Some crumbling and                                   Particle integrity main-           footwork; and after                       then packs down with                                   tained; little fining or           moisture is absorbed                       accumulating moisture.                                   dust.           and then become dry.StainingAnimals         None        None        None           --Caging          None        None        None           --Attractiveness as Feed           None        None        None           --__________________________________________________________________________ .sup.1 5-days use .sup.2 6-days use 
    
     As can be seen by comparing the results shown in Table II, with those shown in Table I, the litter formulation without alfalfa was as good or better than formulations 1, 2 and 3. However, there is some tendency for these pellets to crumble with use. 
     EXAMPLE 3 
     The procedure of Example 1 was followed to prepare the formulations as indicated in the following Table III, except that sodium bicarbonate was added where indicated as an odor suppressor. 
     
                       TABLE III______________________________________% CompositionFormula  PeanutNo.    Hulls    Alfalfa Bentonite Clay                              Fat  NaHCO.sub.3______________________________________5      98       0       2          0    06      95       0       5          0    07      97       0       2          0    18      96       0       2          0    29      96       0       2          2    010     93       0       2          5    011      0       98      2          0    0______________________________________ 
    
     Water absorption values were obtained in the same manner as in Example 1. However, less total absorption occurred than in Example 1. On two-hour absorption tests Formula 5 absorbed 216%, 6) 246%, 7) 218%, 8) 224%, 9) 230%, 10) 242%, 11)349%. Shop-rite, K-Mart, and Litter Green brands of alfalfa absorbed 319,307 and 356% respectively. Overnight absorption values were higher than the 2 hour values but not as high as those of Example 1. However, the same relative differences were obtained for 2-hour and overnight absorption values. 
     After running absorption values, wet samples were left from Friday until Monday at room temperature. Alfalfa samples generally had more objectionable odor than either of the peanut hull samples with Formula 8 having the most desirable odor (slightly sweet). Pellet integrity (ability to hold together wet) was checked on all formulas and found to be best for Formulas 7 and 8, both of which contained NaHCO 3 . Additional observations were made on &#34;tracking&#34; problems and all products tended to &#34;track&#34; when &#34;fingerprinted&#34; onto dark cloth. However, alfalfa products were judged to be a real problem due to the &#34;grass-type&#34; stain transferred onto cloth after the product was wet. 
     EXAMPLE 4 
     Formulations were prepared in accordance with the procedure of Example 1, using the ingredients as indicated in Table IV. 
     
                       TABLE IV______________________________________A. Physical Data% CompositionFormula  Peanut                       AbsorptionNo.    Hulls     Bentonite Clay                        NaHCO.sub.3                               % H.sub.2 O Uptake______________________________________12     97.5      2             0.5  32613     97        2           1      33714     96        2           2      31415     94        2           4      26616     90        2           8      20117     98 (Alfalfa)            2           0      38418     Commercial Litter Green                         38919     96        2           2      273Odor DataFormula No.     % NaHCO.sub.3                Rank (1 best)                           Odor Comments.sup.1______________________________________15        4          1          a13        1          2          b19        2          3          c14        2          4          d12        0.5        5          e16        8          6          f17        Alfalfa 98%                7          g18        Comm.      8          h     Litter Green______________________________________ .sup.1 a. No odor b. Sweet, slightly grassy c. Sweet, slightly grassy, slightly ammonia d. Sweet, slightly grassy, slightly ammonia e. Slightly grassy, slightly ammonia, slightly putrid f. Slightly grassy, slightly ammonia, slightly putrid g. Strong grassy odor, strong ammonia h. Very strong grassy odor, strong ammonia 
    
     All values expressed as % are % by weight unless otherwise indicated. 
     The litter compositions of this invention are particularly useful as a cat litter.