Performance and digestibilities of beef cattle fed diets supplemented with either soybean meal or roasted soybeans and implanted with Synovex.

Two 160-d feedlot experiments, each consisting of 20 Angus-Hereford steers (216 +/- 5 kg BW, Exp. 1; 258 +/- 5 kg BW, Exp. 2) and 20 Angus-Hereford heifers (208 +/- 5 kg BW, Exp. 1; 236 +/- 5 kg BW, Exp. 2), were used to investigate the effects of supplementing diets with either roasted soybeans (RSB, roasted at 127 degrees C for 10 min) or soybean meal (SBM) and implanting or not implanting with an estrogenic growth promoter (SYN; Synovex-S, 20 mg of estradiol benzoate plus 200 mg of progesterone or Synovex-H, 20 mg of estradiol benzoate plus 200 mg of testosterone) on performance. The cattle were fed a basal diet of 15% orchardgrass silage, 15% corn silage, and 70% corn-based concentrate. Treatments were 1) no SYN and fed a SBM-supplemented diet, 2) no SYN and fed a RSB-supplemented diet, 3) SYN and SBM, and 4) SYN and RSB. Cattle in the SYN groups were reimplanted at 80 d. Four additional Angus-Hereford steers were used in a digestion and nitrogen balance experiment conducted during the first half of Exp. 1. For the total 160-d feedlot experiments, DMI for RSB compared with SBM was lower (P < .01; 8.5 vs 9.2 kg/d, SEM = .07) and ADG/DMI tended to be higher (P < .10; 165 vs 157 g/kg, SEM = 1.3). Final BW of steers fed RSB was similar (P > .10) to that of steers fed SBM (473 vs 478 kg, SEM = 5.6), as was ADG (1.39 vs 1.43 kg/d, SEM = .02). Dry matter intake for SYN-implanted steers was higher (P < .01) than for steers not implanted (9.2 vs 8.5 kg/d). Likewise, final BW (491 vs 460 kg) and ADG (1.49 vs 1.33 kg/d) were higher (P < .01), and ADG/DMI (166 vs 157 g/kg) tended to be higher (P < .10), for SYN-implanted steers than for steers not implanted. During the more rapid muscle growth period (0 to 80 d), DMI for RSB compared with SBM was lower (P < .01; 7.8 vs 8.6 kg/d, SEM = .07) and ADG/DMI was similar (P > .10; 181 vs 172 g/kg, SEM = 1.8). Dry matter intake for SYN-implanted steers was higher (P < .05) than for steers not implanted (8.4 vs 8.0 kg/d), as was ADG/DMI (P < .01, 182 vs 171 g/kg). During this more rapid growth period, the supplement x implant interaction for ADG was significant (P < .05; 1.35, 1.36, 1.59, and 1.44 kg/d for Treatments 1, 2, 3, and 4, respectively, SEM = .04). There were no differences in digestibilities or N balance. The results suggest that there is no improvement in performance under feedlot conditions when RSB replaces SBM in the diet of beef cattle, and, in young cattle, RSB may reduce the response expected by an estrogenic growth promoter.

The effects of high-forage diets with added palm oil on performance, plasma lipids, and carcass characteristics of ram lambs with initially high or low plasma cholesterol.

The objectives of this study were to examine the interaction between added palm oil in high-forage diets and initial concentration of plasma cholesterol on performance, plasma lipids, and carcass characteristics of growing ram lambs. Thirty-two Hampshire-Suffolk ram lambs (initial BW = 34.4 kg) were assigned to a 2 x 2 factorial design consisting of diet (basal [NPO] or 10.7% added palm oil [PO]) and initial plasma cholesterol concentration (high mean = 50 mg/dL [HC] or low mean = 38 mg/dL [LC]; SEM = 2; P = .01). The lambs were individually fed diets (77% forage-23% concentrate) that contained 16.0% CP, 2.14 Mcal of ME/kg (NPO), and 2.62 Mcal of ME/kg (PO). Metabolizable energy intakes were adjusted to .20 Mcal/kg of BW.75 for both dietary treatments. Lambs were weighed and feed intakes adjusted weekly. Lambs were bled via jugular venipuncture on d 28, 56, and 84 and lambs were slaughtered after they had been fed the diets for 90 d. Plasma concentrations of total cholesterol, high-density lipoprotein cholesterol, triglycerides, and nonesterified fatty acids were increased (P = .01) by feeding PO. Lambs fed PO were fatter than lambs fed NPO, as indicated by greater subcutaneous fat thickness and kidney and pelvic fat. Initial plasma cholesterol concentration had little effect on any of the parameters measured. Lambs fed PO had fatter carcasses than lambs fed NPO at calculated equalized ME intakes, which indicates that energy deposition is more efficient in palm oil-supplemented diets.

Effects of high-forage diets with added palm oil on performance, plasma lipids, and carcass characteristics of ram and ewe lambs.

The objectives of this study were to determine the effects of high-forage diets with and without added dietary palm oil (high in palmitic acid) fed at equalized ME intakes on performance, plasma lipids, and carcass characteristics of growing ram and ewe lambs. Thirty-one Hampshire or Suffolk lambs (35.7 kg BW) were used in a 2 x 2 factorial arrangement of the following treatments: 1) rams, no palm oil (R-NPO); 2) ewes, no palm oil (E-NPO); 3) rams, 10.7% dietary palm oil (R-PO); and 4) ewes, 10.7% dietary palm oil (E-PO). Both diets consisted of 77% forage and 23% concentrate. Diet DM contained 15.0% CP and 2.14 Mcal of ME/kg (NPO) or 2.62 Mcal of ME/kg (PO). Lambs were fed individually specified amounts of diet based on BW to equalize ME intake (.20 Mcal of ME/kg of BW.75) for both dietary treatments. Lambs were weighed and feed intakes were adjusted weekly. Lambs were bled by jugular venipuncture on d 28, 56, and 84 and were slaughtered after they had been fed the diets for 90 d. Lambs fed PO had greater (P < .01) ADG and efficiency (ADG/ME intake) than lambs fed NPO. Plasma concentrations of cholesterol, high-density lipoprotein cholesterol, triglycerides, and nonesterified fatty acids were increased (P < .01) by feeding PO. Lambs fed PO were fatter than lambs fed NPO, as evidenced by greater subcutaneous fat thickness and kidney and pelvic fat. Ewes had greater (P < .01) subcutaneous fat than did rams.(ABSTRACT TRUNCATED AT 250 WORDS)

Nitrogen metabolism of lactating ewes fed rumen-protected methionine and lysine.

Twenty multiparous, crossbred, black-faced ewes and their newborn twin lambs were assigned to one of four dietary treatments in a 2 x 2 factorial experiment to examine the effects of increased supply of CP or a mixture of encapsulated methionine and lysine or both on the performance of ewes and their nursing twin lambs. Ewes were fed ad libitum amounts of either a 10.2% low CP diet or a 16.2% moderate CP diet with or without additional encapsulated amino acids. Nitrogen metabolism trials were conducted simultaneously on both ewes and lambs at wk 2, 4, and 8 of lactation. Analyses were conducted for blood urea N, plasma 3-hydroxybutyrate, lactate, NEFA, insulin, and amino acids (plasma, feed, and milk). Ewe DMI, BW, BW gain, and milk yield were not changed by dietary treatments. Balance of N and N digested were increased by moderate CP treatment. The portion of retained N used for milk synthesis was increased by low CP treatment. Methionine and total branched-chain amino acids were increased by encapsulated amino acids and by protein treatment. Gains in BW and N balance were increased in lambs nursing ewes fed protected amino acids. Increased growth of nursing lambs would be an important beneficial effect of supplementing diets of ewes with encapsulated methionine and lysine.

Mineral deposition in diethylstilbestrol- and Synovex-treated steers.

The effects of diethylstilbestrol (DES) and Synovex-S hormonal growth promotants on composition of body ash deposited by feedlot beef steers were studied in two slaughter-balance trials. Trial 1 consisted of three groups of eight Hereford steers averaging 225 kg initial body weight. One group was initially slaughtered (IS) at the beginning of the trial and two groups, control (C) and DES-treated (20 mg/steer daily in diet), were fed for 177 d and then slaughtered. Trial 2 consisted of 28 Hereford steers averaging 310 kg initial body weight. Four steers were IS and 24 steers were assigned to a factorial arrangement of treatments (- or + Synovex-S ear implant and - or + dietary kiln dust), fed for 126 d and slaughtered. Each Synovex-S ear implant contained 200 mg progesterone and 20 mg estradiol benzoate. Kiln dust (KD) was fed as a digestive tract buffer, and the +KD diets contained 1.23% Ca and .37% P compared with .45% Ca and .36% P in -KD diets on an as-fed basis. Mineral concentration in body tissue was greater for IS than for fed steers reflecting deposition of soft tissue, particularly fat, during the feeding period. Mineral concentration in body tissue was similar between C and hormonally-treated steers. Mineral composition of tissue ash in IS, C and hormonally-treated steers and composition of ash deposited during the feeding period for C and treated steers were similar. The results suggest that both DES and Synovex treatments of beef steers do not cause an increased propensity for skeletal growth but that ash deposition is of similar composition in C and treated steers.