The effect of diethylstilbestrol (DES) on the composition of tissue gain of Hereford steers was studied in a complete slaughter balance trial. Eight steers were slaughtered initially (IS) and, after 177 days on feed, eight control steers (C) and seven steers that had been fed 20 mg DES daily (DES) were slaughtered. Initial full body weight averaged 224.8 kg, and final full body weight averaged 403.0 kg for the C steers and 433.6 kg for the DES steers. Final empty body weight averaged 346.6 kg for the C steers and 368.0 kg for the DES steers. DES improved live weight gain by 17% and conversion of feed dry matter to live weight by 12%. Recovery of wet weight during slaughter averaged 99.6%. DES steers had larger rib cut weights and greater proportions of separable lean and bone plus connective tissue in the rib cuts than C steers, an ribeye area tended to be larger in DES steers. DES caused a small shift in relative body composition toward more protein, moisture and ash. Tissue gain in DES steers consisted of 28.3% more protein, 26.0% more moisture, 73.2% more ash, 1.5% less fat and 109.1% more residual (dry matter not accounted for by N x 6.25, ether extract and ash) than did tissue gain in C steers. Energy gain per unit of energy intake over the feeding period was not affected by DES treatment, but DES improved protein gain per unit of protein intake and per unit of energy intake by approximately 20% within the total empty body and by about 25% within the carcass fraction. Results confirm indirect estimates in the literature indicating that DES increases skeletal growth and lean tissue deposition in feedlot steers.

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Fecal coliform bacteria were isolated from three herbivores (cattle, horse, and red panda) and shown to produce primarily the D-form of lactate, plus acetate and ethanol when grown anaerobically in 1.0% glucose broth. To evaluate coliform contribution to D-lactate acidosis in cattle, experiments involving a forage-adapted steer (fasted or normally fed) and four 500-ml fermentors were compared during 3 d of grain overload. In both systems, coliforms and D- and L-lactic acid production were greater from fasted than from normally fed steer inoculum. With fasted inoculum, coliform counts peaked (3 x 10(7)/ml at 7 h after initial engorgement) and receded to 10(3)/ml by the time D-lactate concentration peaked, indicating that bacteria other than coliform were responsible for the delayed peaking of D- (48 h) compared with L-lactate (24 h). Increases in lactobacilli more closely mimicked D-lactate increases than did changes in coliforms. The comparisons between the steer and fermentors showed many similar shifts in end-products and groups of bacteria, more so with the experiment initiated with fasted than with normal inoculum. With normal inoculum, VFA content and moles of butyrate/100 mol of VFA were greater in vitro than in vivo; VFA content presumably was larger because of VFA absorption in vivo. In a separate experiment, cultures initiated with identical inoculum and given the same amount of feed accumulated more lactate when pH was permitted to decrease to 5.0 than when pH was maintained at 5.5 for 6.0 or above, indicating the role buffers can have in controlling acidosis during diet change to concentrates.

Samples of fresh apple pomace were collected from 14 loads of apple pomace as delivered from the processing plant in October 1968 and from stored apple pomace that had been obtained in October 1967 and fed during a feeding trial from mid-November 1967 through April 1968. All samples were analyzed for dicofol (kelthane), tetradifon (tedion), DDT, DDD and DDE. For the pesticide residues in fresh apple pomace, the difference between the low and high load means was greater than 10-fold and these differences between loads were significant (P<.01) for DDT, DDD and DDE. The pesticide residue content of stored apple pomace during a feeding trial ranged from .36 to 1.16 ppm for dicofol, .07 to .53 for tetradifon, 1.00 to 3.57 for DDT, .38 to .94 for DDD and .30 to .74 for DDE, which demonstrated potentially wide variation in pesticide intake during an apple pomaee feeding period. Accumulation of pesticide residues in the fat depots of 28 pregnant beef cows was significant when apple pomace was fed for 160 days. Accumulation of residues was not affected by the type of nitrogen supplementation or by the inclusion of oil in the diet. Accumulation of residues appeared greater when pesticides were added to a simulated apple pomace diet than when apple pomace was fed. Tetradifon, DDT and DDD accumulated at a similar rate in fat tissue; 29% as fast as DDE. Dicofol accumulated 8% as fast as tetradifon. Total DDT residues (sum of DDT, DDD and DDE) were highest in heart fat, lowest in brisket and t Ruminant Nutrition Laboratory, Nutrition Institute, ARS.