Greater Molar Proportions Research Articles

PSXVI-23 The influence of trace mineral source on digestion, ruminal fermentation characteristics, and mineral solubility in beef cattle fed a high concentrate feedlot diet

Abstract Twelve Angus steers (BW 530.9 ± 22.7kg) fitted with ruminal cannulae were used to determine the impact of trace mineral (TM) source on digestibility and ruminal VFA and soluble concentrations of Cu, Mn, and Zn. Steers were fed a high concentrate diet balanced to meet the requirement of finishing feedlot steers for 21d. Treatments consisted of Cu, Mn, and Zn supplemented at 18, 40, and 90 mg/kg DM, respectively, from either sulfate (STM) or hydroxy trace mineral (HTM) sources (n = 6 steers/treatment; experimental unit = steer). Following a 21-d adaptation period total fecal output was collected for 5 d. Trace mineral sources had no impact on nutrient digestibility. On d 6, rumen fluid was collected at 0, 2, and 4 h post-feeding for VFA analysis. There were no treatment x time interactions for any VFA measured. However, HTM steers had greater (P < 0.05) ruminal molar proportions of propionate and tended (P < 0.07) to have greater molar proportions of valerate compared to STM steers. Steers fed STM had greater (P < 0.05) molar proportions of butyrate compared to HTM steers. Steers were then fed the same high concentrate diet without supplemental Cu, Zn, or Mn for 14 d. On d 15 steers received a pulse dose (via rumen cannula) from either STM or HTM. Ruminal samples were obtained at 2 h intervals starting at -4 and ending at 24 h relative to dosing. There was a treatment x time interaction (P < 0.05) for ruminal soluble Cu concentrations. Ruminal soluble mineral concentrations were greater (P < 0.05) for Cu at 4, 6, 8, and 16 h post-dosing in STM compared to HTM supplemented steers. Results indicate that ruminal solubility of Cu differs between STM and HTM sources and may impact rumen fermentation characteristics.

532 Intake, digestibility and ruminal parameters in cattle fed with oil, selenium and vitamin E

This study aimed to evaluate intake, ruminal parameters and digestibility of nutrients in the diets with 6% soybean oil (SO) and with or without supplementation of organic selenium (Se) and vitamin E (E). Five steers cannulated with average initial BW of 398 ± 28.7 kg were subjected to a 5 × 5 Latin Square with 21d periods. Diets consisted of 65% concentrate and 35% corn silage. Steers were assigned to treatments: without additional oil (WAO); SO; SO+E; SO+Se; SO+E+Se. The additives were daily supplemented with 1500 IU vitamin E and 5 g selenium per animal. Rumen contents were collected every two hours after morning feeding to measure SCFA and ammonia nitrogen. Total collection of feces was completed for three days in each period to measure digestibility of nutrients. The data were analyzed using PROC MIXED of SAS. The diet with SO had lower intake (kg) of DM (9.82 and 10.6; P= 0.02), DMBW (21.05 g/kg BW and 23.1 g/kg BW; P<0.01), OM (9.96 and 10.8; P= 0.05), CP (1.25 and 1.36; P= 0.02), NDF (3.20 and 3.52; P= 0.01), and NFC ( 4.22 and 5.11; P<0.01), total protozoa (45 and 380 103/mL; P<0.01), total digestibility (g/kg) of DM (726 and 760; P= 0.05), OM (725 and 759; P = 0.05), NFC (814 and 845; P= 0.04) and NDF ( 567 and 639; P<0.01), ruminal digestibility (g/kg) of CP (426.50 and 511; P= 0.05) and NDF (505.75 and 587; P<0.01), and excretion of N microbial (202 and 156.2 g/day; P= 0.01). However, SO had a greater intake (0.85 and 0.33; P<0.01) and total digestibility of EE (897.25 and 826; P<0.01) than WAO. Se reduced ruminal digestibility of DM (475 and 508.5; P= 0.05) and OM (475 and 509; P= 0.05) and had greater molar proportion (mMol) of acetate (35.6 and 30.45; P= 0.04), propionate (19.1 and 16.0; P= 0.04), butyrate (9.53 and 8.37; P= 0.05) than diet without Se. The diet with SO+E+Se had lower ruminal digestibility of CP (417 and 511; P= 0.04) and greater EE (-56.5 and 159; P= 0.05). Overall, the study showed that supplementation with soybean oil reduce DM intake and fiber digestibility, while the use of E/Se does not change the total digestibility of nutrients.

Reactions of unsaturated and macromolecular compounds Communication 5. Copolymerization of methyl acrylate with vinyl ethers

1. The conditions required for the copolymerization of methyl acrylate with ethyl, butyl, and phenyl vinyl ethers have been studied. Copolymers of methyl acrylate with ethyl, butyl, and phenyl vinyl ethers have been prepared. 2. It has been shown that the composition of the copolymers obtained depends on the concentrations of vinyl ethers and methyl acrylate in the given reation mixtures. 3. Copolymers of methyl acrylate with vinyl ethers contain greater molar proportions of the latter than the copolymers of methyl methacrylate with the same vinyl ethers.