Carcass

Toxicity. Sodium fluoroacetate is one of the most effective all-purpose rodenticides known (18). It is highly toxic to all species of rats tested and can be used either in water solution or in bait preparations. Its absence of objectionable taste and odor and its delayed effects lead to its excellent acceptance by rodents. It is nonvolatile, chemically stable, and not toxic or irritating to the unbroken skin of workers. Rats do not appear to develop any significant tolerance to this compound from nonlethal doses. However, it is extremely dangerous to humans, to common household pets, and to farm animals, and should only be used by experienced personnel. The rodent carcasses should be collected and destroyed since they remain poisonous for a long period of time to any animal that eats them. 

NaturaHy occurring and synthetic estrogens and androgens have been extensively and safely used to improve efficiency and carcass composition ia growing beef catde in the United States since the early 1950s. Several anaboHc steroid implants have been approved for use in beef catde in the United States, but only one, zeranol [55331-29-8] is approved for use in lambs. Anabolic steroids are not used for growth regulation in swine or poultry (see Steroids). 

Growth Performance Response. The consistent net effect of anaboHc steroid implant use in growing mminants appears to be increased rate of protein and Hve weight gain, and increased Hve weight at which carcass or empty body fat concentration equals that in nonimplanted cattie thus increasing their potential mature size. Increased feed intake is frequentiy observed. 

Very Htfle data are available regarding effects of anaboHc steroid implants on the Hpid metaboHsm in growing mminants. Lipogenic enzyme activity and fatty acid synthesis in vitro were elevated in subcutaneous adipose tissue from bulls implanted with estradiol (44), which may account for the increase in fat content of carcasses reported in some studies. TBA implants have no effect on Hpogenesis in intact heifers, and only tend to reduce Hpogenic enzyme activities in ovariectomized heifers (45). 

Economics. Estimates of anaboHc steroids in growing cattle indicate that savings associated with reduced feed costs are approximately 50.00 per animal. Increased value of the carcass resulting from the increased amount of saleable lean meat produced is estimated to range from 15.00 to 30.00 per animal. 

Lambs received saline, oST at 40 )-lg/kg BW, or the indicated dose of hGRF per kg BW four times per day for 42 or 56 days. Half of the lambs were withdrawn from treatment after 42 days. Carcass data shown are for lambs treated 56 days. Carcass composition data were analy2ed by analysis of variance using carcass weight as the covariate. Data are summarized in Ref. 85. 

The more variable responses with growing catde appear to result from lower doses, nutritional constraints, or lesser responsiveness of younger animals, ie, veal calves. A dose-dependent reduction in feed intake in finishing cattle, which also reduced average daily gain, has been observed (84). However, carcass composition was improved in a dose-dependent manner. 

Table 4. Effects of p-Agonists on Growth and Carcass Composition of Growing Lambs...

ADG/g / d Feed gain Carcass Proteia composition, % Lipid ... 

Data for carcass composition corresponding to protein and lipid are percent-dissected skeletal muscle and adipose, respectively. 

J. P. Hanrahan and co-workers, Beta-Agonists and Their Effects on Animal Growth and Carcass Quality, Elsevier Apphed Science, London, 1987, pp. 106-118. 

Ref. 3. Carcass-weight basis, excludes offals, rabbit, and poultry meat. Includes edible pork fat, but excludes lard and edible greases (except United Less than 1000 metric tons. 

Ref. 1. Carcass-weight equivalent for red meat ready-to-cook equivalent for poultry. 

Fig. 1. Red meat and poultry production in the United States (1). Red meat is based on carcass weight, poultry is based on ready-to-cook weight, and 1991 production is preliminary data. (O) Veal, ( ) beef, (A) chicken, (A) pork, (D) lamb, and (B) turkey.

Selenium. Selenium, thought to be widely distributed throughout body tissues, is present mostly as selenocysteine in selenoproteins or as selenomethionine (113,114). Animal experiments suggest that greater concentrations are in the kidney, Hver, and pancreas and lesser amounts are in the lungs, heart, spleen, skin, brain, and carcass (115). 

In the category of industrial appHcations, nylon is the predominant fiber used in the carcass of bias tmck, racing car, and airplane tires because of its exceUent strength, adhesion to mbber, and fatigue resistance. Nylon is used less in the carcass of radial tires for automobiles and in replacement bias and bias-belted tires because of the development of temporary flat spots. For this reason, nylon has lost most of this market to polyester. 

The tread is desigaed and compounded for abrasion resistance, traction, low rolling resistance, and protection of the carcass. It often is divided iato two subcomponents to maximize performance the outer tread for surface contact, and the undertread for tying iato the carcass while reduciag tire rolling resistance through decreased hysteresis. 

The steel belt, which provides strength and protection for the ply or pHes, is encased ia a compouad that must possess adhesioa to the steel which provides stress transfer from the very rigid steel to the many times more flexible tread, sidewall, and textile carcass components. The wedge compound is formulated to reduce belt-edge sheer stresses while tying the belt to the carcass and reduciag hysteresis. 

The carcass ply/pHes coat compouad fuactioas are basically the same as the steel breaker compouad. Normally ia the steel belted PCT the ply is textile cord of polyester or rayoa fabrics which are soft and flexible. The tmck radial steel tire normally uses a steel cord ply. Earthmover tires are of two basic constmctions, ie, radial usiag steel and bias usiag textiles (see Tire cords). 

---