Patent Application: US-28548308-A

Abstract:
a method for improving efficiencies in livestock production comprises grouping livestock animals , such as cattle and pigs , during the period of their retention in a feeding facility according to the genetic predisposition of individual livestock animals to deposit fat , and then feeding the animals in each group substantially uniformly . such genetic predisposition is determined by determining homozygosity or heterozygosity of each animal with respect to alleles of a gene encoding an adipocyte - specific polypeptide , termed leptin , which gene is hereinafter referred to as ob , segregating such animals into groups based on genotype and optionally phenotype , feeding and otherwise maintaining animals in a group together and apart from other groups of animals , and ceasing to feed the animals in the group at a time when the median body fat condition of the animals of that group is a desired body fat condition . packers can also more accurately predict the fat deposition in carcasses of live animals it purchases , leading to increased efficiencies .

Description:
other objects , features and aspects of the present invention are disclosed in , or are obvious from , the following detailed description . it is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present invention , which broader aspects are embodied in the exemplary construction . in fact , it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention . for instance , features illustrated or described as part of one embodiment can be used in another embodiment to yield a still further embodiment . it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents . for convenience , certain terms employed in the specification , examples , and appended claims are collected herein as follows : the term “ animal ” is used herein to include all vertebrate animals , including humans . it also includes an individual animal in all stages of development , including embryonic and fetal stages . as used herein , the term “ production animals ” is used interchangeably with “ livestock animals ” and refers generally to animals raised primarily for food . for example , such animals include , but are not limited to , cattle ( bovine ), sheep ( ovine ), pigs ( porcine or swine ), poultry ( avian ), and the like . as used herein , the term “ cow ” or “ cattle ” is used generally to refer to an animal of bovine origin of any age . interchangeable terms include “ bovine ”, “ calf ”, “ steer ”, “ bull ”, “ heifer ” and the like . the term “ avian ” as used herein refers to any species , subspecies or race of organism of the taxonomic class ava , such as , but not limited to , such organisms as chicken , turkey , duck , goose , quail , pheasants , parrots , finches , hawks , crows and ratities including ostrich , emu and cassowary . as used herein , the term “ pig ” or is used generally to refer to an animal of porcine origin of any age . interchangeable terms include “ piglet ”, “ sow ” and the like . as used herein , the term “ genome ” refers to all the genetic materials in the chromosomes of a particular organism . its size is generally given as its total number of base pairs . within the genome , the term “ gene ” refers to an ordered sequence of nucleotides located in a particular position on a particular chromosome that encodes specific functional product ( e . g ., a protein or rna molecule ). for example , it is known that the protein leptin is encoded by the ob ( obese ) gene and appears to be involved in the regulation of appetite , basal metabolism and fat deposition in general , an animal &# 39 ; s genetic characteristics , as defined by the nucleotide sequence of its genome , are known as its “ genotype ”, while the animal &# 39 ; s physical traits are described as its “ phenotype .” as used herein , the term “ locus ” or “ loci ” refers to the site of a gene on a chromosome . pairs of genes , also known as “ alleles ” control the hereditary traits , each in the same position on a pair of chromosomes . these alleles , which also may be described as an animal &# 39 ; s “ allelotype ” may both be dominant or recessive in expression of that trait . in either case , the individual is said to be homozygous for the trait controlled by that gene pair . if the gene pair ( alleles ) consists of one dominant and one recessive trait , the individual is heterozygous for the trait controlled by the gene pair . the term “ nucleotide ” generally refers to a subunit of dna or rna consisting of a nitrogenous base ( adenine , guanine , thymine or cytosine in dna ; adenine , guanine , uracil , or cytosine in rna ) a phosphate molecule , and a sugar molecule ( deoxyribose in dna and ribose in rna ). thousands of nucleotides are linked to form a dna or rna molecule . a “ single nucleotide polymorphism ” or snp is used herein to refer to the most common type of genetic variation in a gene consisting of a change at a single base in a dna molecule . one example of a snp is the cytosine ( c ) to thymine ( t ) transition within exon 2 of the ob gene , corresponding to an arginine ( arg ) to cysteine ( cys ) substitution in the leptin polypeptide ( buchanan et al . ( 2002 ). as used herein , the term “ protein ” generally refers to a large molecule composed of one or more chains of amino acids in a specific order . the order is determined by the base sequence of nucleotides in the gene coding for the protein . proteins are required for the structure , function , and regulation of the body &# 39 ; s cells , tissues , and organs . each protein has a unique function . a typical growth curve for production animals is illustrated in fig1 . present production practices vary among the specific industries as to the point on the curve at which the animal is considered ready for slaughter . for poultry and pigs , for example , present practice is to slaughter near the beginning of phase three where the growth curve begins to flatten out . at this portion of the curve , the amount of time and feed required to produce a pound of gain increases , and so economics dictates that the animal should be slaughtered at that time , and replaced in the feeding facility with an animal in the second phase where weight gain is much more rapid and efficient in terms of feed conversion . for cattle however , present practice is to slaughter well into phase three . during phase 3 , cattle accumulate fat , which lends palatability to meat . presently cattle are grouped according to weight and visual clues such as frame size and breed traits . the group is then penned together and from that point each animal is substantially fed and otherwise maintained uniformly . when it is determined that the average body condition of the group is a desired body condition , all animals in the group are slaughtered . in cattle production , for example , it is known to use ultrasound devices to measure the back fat on some live animals in an attempt to predict intramuscular fat to better judge when the desired body fat condition has been attained . while accurate measurements of back fat can be made on a live animal , back fat is known to not correlate with any degree of accuracy to intramuscular fat which is marbled through the meat , and which is accepted as adding palatability , and thus brings a premium price . actual intramuscular fat can only be accurately assessed after the animal is slaughtered , when the animal &# 39 ; s carcass is graded . thus , cattle feeders are limited in the success that they can attain in providing slaughter animals that meet the desired palatability grade aaa . presently , a feedlot operator feeds all the cattle in an attempt to most economically ensure that the maximum number achieve the most optimum grade , for example , grade aaa . genotype testing of feeder cattle in a typical feedlot situation by the present inventor showed a direct correlation between genotype and fat deposition . the cattle were confined in conventional pens , fed conventional rations , and slaughtered when discerned by conventional means to be market ready . the cattle were tested to determine the genotype , and were traced to the shipping point to determine the palatability grade achieved . each pen contained a mix of unsegregated cc , ct , and tt cattle . results of the first test ( test 1 ) showed that , of 73 hereford steers tested for genotype , 36 were ct , 37 were tt , while none were cc . the 73 cattle were then slaughtered , 48 . 5 % of the tt carcasses graded aaa , and 19 . 4 % of the ct carcasses graded aaa . in test 2 , of the 50 charolais — angus cross steers tested for genotype , 9 were determined to be cc , 28 were ct , and 13 were tt . when slaughtered , 62 % of the tt carcasses graded aaa , 29 % of the ct carcasses graded aaa , and 11 % of the cc carcasses graded aaa . in test 3 , 13 charolais cattle in each of 5 pens , or a total of 65 animals , were tested for allellotype . of the 65 cattle , 29 were cc , 24 were ct , and 12 were tt . there was a high degree of breeding in the 65 cattle . when slaughtered , 58 . 3 % of the tt carcasses graded aaa , 45 . 5 % of the ct carcasses graded aaa , and 38 . 5 % of the cc carcasses graded aaa . the method of the present invention contemplates grouping production animals according to their genotype or , more specifically , allelotype in addition to using the phenotypic criteria currently employed in feedlot practice . for example , in one embodiment of the present invention , feedlot operators who currently group cattle according to size and frame structure , among other phenotypic traits , would group animals according to allelotype , i . e ., cc , tc , or tt , which correlate with the animal &# 39 ; s propensity to deposit fat , in order to more efficiently manage production . thus the feeder is presented with opportunities for considerable efficiencies in livestock production . presently , the feeder feeds all his cattle the same , incurring the same costs for each animal , and typically , with excellent management practices , perhaps 40 % will receive an optimal grade , such as aaa , and receive the premium price for the palatability grade . of these , a significant number will have excess fat and will thus receive a reduced yield grade . the balance of the cattle , 60 %, will grade less than aaa , and thus receive a reduced price , although the feed lot costs incurred by the feeder are substantially the same for these cattle receiving the lesser grade . grouping and feeding the cattle by genotype and , more specifically , allelotype allows the feeder to treat each group differently with a view to optimizing management strategies and increasing profit . for example , according to one embodiment of the present invention , a group of cc cattle will have the least propensity to deposit fat , and so it could be more profitable to slaughter this group earlier in the growth curve , near the start of phase 3 where the growth curve flattens , since they have the least chance of meeting the fat requirements of the optimum or aaa grade . such a group slaughtered early would have a very high percentage of lean carcasses , and this predictability could itself draw premiums from packers seeking to fill orders requiring lean carcasses . on the other hand , a group of tt cattle will have the most propensity to deposit fat , and so it could be more profitable to keep these on feed longer , since it is predictable that a high percentage would accumulate sufficient intramuscular fat so that the carcass would grade aaa and thus receive a premium price . likewise , knowing that ct cattle deposit fat at an intermediate rate will allow the feed lot operator to manage this group more efficiently and profitably as well . it is contemplated that , regardless of the desirability and premium paid for any particular body fat condition at any given time , providing the packer with a more uniform group that is predictably fat or lean will provide the feeder with the opportunity to demand and receive a premium , relative to the less uniform groups of cattle presently available . the packer will be able to buy more of the cattle with a body fat condition that he actually needs , while buying less cattle in total . the packer can thus be much better able to manage his inventory , reducing surpluses of carcasses with less desirable body fat conditions that would ordinarily be sold at a reduced price . thus the present invention provides a method which , in one embodiment , reduces the inventory of carcasses in beef packing operations by reducing the total number of cattle purchased in order to obtain a desired number of carcasses of a desired grade . the method comprises determining whether animals available for purchase are tt animals ( i . e ., homozygous with respect to the t - allele of the ob gene ), cc animals ( i . e ., homozygous with respect to the c - allele of the ob gene ), or ct animals ( i . e ., heterozygous with respect to the t - allele and the c - allele of the ob gene ). where the desired grade requires fat carcasses , the packer purchases tt animals , and where the desired grade requires lean carcasses , the packer purchases cc animals . the predictability of fat deposition allows the feed lot operator to consider the premiums available for fat or lean carcasses , and tailor his decisions to maximize returns . where production costs are high , as when feed costs are high , the feedlot operator might profit from slaughtering early . when costs are low , it might be more profitable to slaughter later . the feed lot operator can more accurately predict the particular body fat condition of a group of animals at any given point on the growth curve , and thus more effectively make decisions regarding when to slaughter any particular group . it is also contemplated by the method of the present invention that feed rations could be tailored to more specifically achieve a desired body fat condition for each group by managing production animals &# 39 ; genotype generally , and , in particular , the tt / cc / ct allelotype . among animals of the same species and substantially the same age and weight , where other determinants of growth such as health condition and diet are equivalent , smaller framed animals will reach a stage of maturity exemplified by the start of the third phase of growth earlier than larger framed animals . therefore , substantial leptin effects will be evidenced earlier in such smaller framed animals than in larger framed animals . where other determinants of growth such as health condition and diet are equivalent , a group of animals of the same species , sharing substantially the same age , weight , and frame type will attain the stage of maturity exemplified by the start of the third phase of growth at a substantially more uniform time than an otherwise equivalent group of animals , the individual members of which do not share substantially the same frame type . therefore , where other determinants of growth are equivalent , substantial leptin effects will begin to be evidenced at a more uniform time in animals of a group segregated on the basis of frame type than in animals of a group not so segregated . importantly , grouping otherwise similar animals based on frame size is a more accurate means of achieving body condition uniformity than grouping otherwise similar animals based on body weight . when compared to large - framed animals , small - framed animals that are of substantially the same age and weight will attain the third phase of growth earlier , begin to accumulate significant amounts of body fat earlier and , thus , attain a desired body fat condition earlier . if individual animals so grouped have different ob genotypes , substantial evidence of such difference will be exhibited at substantially uniform times . among animals sharing substantially the same weight and frame type , tt animals will accumulate fat faster during the third phase of growth than ct animals , and ob heterozygotes will accumulate fat faster during the third phase of growth than cc animals . one embodiment of the present invention provides a method to facilitate attainment of greater efficiency in a commercial livestock feeding and finishing facility by providing a method comprising determining the genetic predisposition of each animal to deposit fat by determining ob genotype and segregating individual animals into subgroups based upon the ob genotype . thus , using the method of the present invention allows an operator to produce a livestock animal group comprising a plurality of individual animals of the same species wherein a median body fat condition of the individual animals is a desired body condition and wherein actual body fat conditions of the individual animals are improvedly uniform . the method of the present invention also provides a packer with a more uniform group that is predictably fat or lean ensuring the feed lot operator with the opportunity to demand and receive a premium , relative to the less uniform groups of cattle presently available . for example , in accordance with one embodiment of the present invention , the packer will be able to buy more cattle with a body fat condition that he actually needs , while buying less cattle in total . the packer can thus be much better able to manage his inventory , reducing surpluses of carcasses with less desirable body fat conditions that would ordinarily be sold at a reduced price . the predictability of fat deposition allows the feed lot operator to consider the premiums available for fat or lean carcasses , and tailor his decisions to maximize returns for each group . where costs in the feedlot are high , as when feed costs are high , the operator might profit from slaughtering early . when costs are low , it might be more profitable to slaughter later . the feed lot operator , using the method of the present invention is able to more accurately predict the particular body fat condition of a group of animals at any given point on the growth curve , and thus can more effectively make decisions regarding when to slaughter any particular group . it is also contemplated that , where demand for optimum grade , such as aaa , beef is high , feed lot operators will pay a first price for cattle homozygous with respect to the t - allele of the ob gene , and pay a second price lower than the first price for cattle heterozygous with respect to the t - allele and c - allele of the ob gene , and pay a third price lower than the second price for cattle homozygous with respect to the c - allele of the ob gene . packers can also set premiums for cattle based upon predicted carcass grade by genotype . the above - stated embodiments of the present invention are achieved by collecting an assembly of individual animals of substantially similar weights and frame types that have lower percentages of body fat than are required to exemplify the desired body fat condition . prior to or upon collection of such assembly at the site of a livestock feeding facility , it is determined whether the animal is homozygous with respect to the t - allele of the ob gene , homozygous with respect to the c - allele of the ob gene , or heterozygous with respect to both t - and c - alleles . a tissue sample containing chromosomal dna can be collected from each individual animal to determine ob genotype . known means can be used t o disrupt animal c ells and process animal tissue samples consistent with the maintenance of chromosomal dna integrity in such tissue samples . standard molecular biology textbooks such as sambrook et al . eds “ molecular cloning : a laboratory manual ” 2nd ed . cold spring harbor press ( 1989 )( the contents of which are incorporated by reference herein in its entirety ) may be consulted to design suitable protocols for the isolation of dna samples from tissues of choice . it should be recognized , however , that the choice of a suitable tissue or sample for the isolation of dna suitable for determining ob genotype depends upon multiple factors including the ease of obtaining the sample from the animal and the quantity of dna present in the sample . tissues of choice include , but are not limited to , hair , epithelial cells , blood , nasal and vaginal swabs and the like . each sample is processed by conventional methods such that the chromosomal dna is purified or partially purified . the purified dna is then assayed to distinguish the presence therein of a wild - type allele of the ob gene and a mutant allele of the ob gene using methods known to one skilled in the art of molecular biology . any method for determining genotype can be used for determining the ob genotype in the present invention . such methods include , but are not limited to , dna sequencing , rflp analysis , microsatellite analysis , polymerase chain reaction ( pcr ), ligase chain reaction ( lcr ), amplimer sequencing , nucleic acid hybridization , fret - based hybridization analysis , size chromatography ( e . g ., capillary or gel chromatography ), high throughput screening , mass spectroscopy , and fluorescence spectroscopy , all of which are well known to one of skill in the art . in particular , methods for determining nucleotide polymorphisms , particularly single nucleotide polymorphisms , are described in u . s . pat . nos . 6 , 514 , 700 ; 6 , 503 , 710 ; 6 , 468 , 742 ; 6 , 448 , 407 ; 6 , 410 , 231 ; 6 , 383 , 756 ; 6 , 358 , 679 ; 6 , 322 , 980 ; 6 , 316 , 230 ; and 6 , 287 , 766 and reviewed by chen and sullivan , pharmacogenomics j 2003 ; 3 ( 2 ): 77 - 96 , the disclosures of which are incorporated by reference in their entireties . one conventional means for distinguishing allelles is by mismatch pcr - rflp . for example , as applied to an advantageous embodiment of the invention , synthetic oligonucleotide - primed amplification of the exon 2 of the ob gene followed by restriction endonuclease treatment of the amplified dna product thereof using kpn 21 results in a cut of the amplimer corresponding to the c allele of the ob gene , but the amplimer corresponding to the t allele is not cut . genotyping of genotype may be carried out by testing at the intake of a feeding facility or at any time during the life of the animal and recorded , conveniently on an ear tag or the like that moves with the animal so that it is readily available . once the genotype is determined , individual animals are segregated into groups wherein each animal shares the same ob genotype , ie . ob − ( a tt animal ), ob ( a ct animal ), or ob + ( a cc animal ), according to the method of the present invention . the animals of each group are maintained and fed together , such that the environmental , health , nutritional , and other conditions and needs of all such animals are maintained and satisfied to a substantially equivalent extent and by substantially equivalent means . because a tt animal , exhibits an increased rate of body fat deposition compared to a c t animal , which in turn exhibits an increased rate of body fat deposition compared to a cc animal , feedlot operators are able to treat each group differently with a view to optimizing management strategies and increasing profit . the invention also provides a method of breeding a livestock animal with a propensity to accumulate body fat as a proportion of total body weight at a rate that is ,: ( i ) predictable ; ( ii ) either greater than or lesser than other livestock animals of the same species when such individual livestock animal and such other individual livestock animals are fed and maintained under conditions of substantial equivalence ; and ( iii ) shares a substantially similar temporal time - course with animals of the same or determinably similar parentage . this object is achieved by collecting male and female livestock animals of the same species and known frame types , or germinal tissue therefrom ; collecting from each above - said animal a tissue sample containing chromosomal dna ; and genotyping each tissue sample according to the means above - described , or according to equivalent means known in the art . individual male and female livestock animals are selecting for breeding with one another based on frame type and genotype such that : ( a ) large , intermediate or small frame - type progeny animals that exhibit a higher , intermediate or lower total body weight at maturity relative to each other can , with a useful degree of certainty , be predicted to be produced by mating large , intermediate , or small frame - type parental animals respectively ; ( b ) cc or tt or ct progeny ( which can , with a useful degree of certainty , be predicted to evidence , respectively , relatively , lower , higher or intermediate rates of body fat accumulation during the third growth phase of such progeny ) can be produced by mating parental animals with known ob genotypes according known principals of inheritance ; and ( c ) by selecting parental animals based on frame type and ob genotype together , a multiplicity of progeny can be produced that , with a useful degree of certainty according to known principals of inheritance , can be predicted to , when fed and maintained substantially under conditions of substantial equivalence , attain a desired body fat condition with relatively greater temporal uniformity than animals selected according to existing breeding protocols . progeny from parental tt or ct animals will have a propensity to accumulate during growth body fat at a rate greater than the average rate of body fat accumulation by other individual livestock animals of the same species and age maintained in conditions of substantial equivalence but bred according to other protocols which would include cc animals . as the occurrence of the t - allele in the offspring increases , so will the propensity of the offspring to accumulate fat . furthermore , once the ob genotype of a particular progeny is known based upon the ob genotype of the parents , which can be confirmed by determining the ob genotype of the progeny , further progeny of a particular genotype can be propagated according to the methods of the invention . thus , an additional utility of the present invention is the selective breeding for a particular ob genotype once the ob genotypes of the parents are determined , i . e ., according to the principles of mendelian genetics . the foregoing is considered as illustrative only of the principles of the invention . further , since numerous changes and modifications will readily occur to those skilled in the art , it is not desired to limit the invention to the exact operation shown and described , and accordingly , all such suitable changes or modifications in operation which may be resorted to are intended to fall within the scope of the claimed invention . u . s . pat . no . 6 , 277 , 592 to bidwell , c . a ., and spurlock , m . e . 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