This study was conducted to evaluate the use of exogenous enzymes as a potential means of improving the ruminal digestion (i.e., degradability) of alfalfa hay and rice straw. Twenty six enzyme-additives were examined in terms of protein concentration and enzymic activities on model substrates. The exogenous enzymes contained ranges of endoglucanase, xylanase, β-glucanase, αamylase, and protease activities. Six of the enzyme additives were chosen for further investigation. The enzyme additives and a control without enzyme were applied to mature quality alfalfa hay substrate and subsequently incubated in rumen batch cultures. Five of the enzyme additives (CE2, CE13, CE14, CE19, and CE24) increased total gas production (GP) at 48 h of incubation compared to the control (p<0.05). The two additives (CE14 and CE24) having the greatest positive effects on alfalfa hay dry matter, neutral detergent fibre (NDF) and acid detergent fibre (ADF) degradability were further characterized for their ability to enhance degradation of low quality forages. The treatments CE14, CE24, a 50:50 combination of CE14 and CE24 (CE14+24), and control (no enzyme) were applied to mature alfalfa hay and rice straw. For alfalfa hay, application of the two enzyme additives, alone and in combination, increased GP compared to the control at 48 h fermentation (p<0.05), whereas only CE14 and CE14+24 treatments improved GP from rice straw (p<0.05). Rumen fluid volatile fatty acid concentrations throughout the incubation of rice straw were analyzed. Acetate concentration was slightly lower (p<0.05) for CE14×CE24 compared to the control, although individually, CE14 and CE24 acetate concentrations were not different from the control. Increases (p<0.05) in alfalfa hay NDF degradability measured at 12 and 48 h of incubation occurred only for CE14 (at 12 h) and for CE14+24 (at 12 and 48 h). Similarly, ADF degradability increased (p<0.05) with CE14 and CE14+24. As for rice straw, increased DM degradability was observed at 12 and 48 h of incubation for all enzyme treatments with an exception for CE14 at 12 h. The degradability of NDF was improved by all the enzyme treatments at either incubation time, while ADF degradability was only enhanced at 48 h. Overall, the enzymes led to enhanced digestion of mature alfalfa and there was evidence of improved digestibility of rice straw, an even lower quality forage.

In trial 1, eight Holstein heifers weighing 410 kg were used in an 8 x 8 Latin square and fed TMR containing 79.3% alfalfa silage and 20% soybeans. The first four treatments were raw soybeans, soybeans roasted and held for 3 h at the roasting temperature, extruded soybeans, and soybeans roasted in a California Pellet Mill Jet-Sploder. The remaining four treatments were obtained by altering the residence time of soybeans in the Jet Sploder. The temperatures of soybeans exiting the roaster were 117, 126, 138, and 154 degrees C for the last four treatments. The soybeans held 3 h postroasting and the extruded soybeans resulted in the highest estimate of postruminal available lysine. Blood plasma concentrations of essential and branched-chain AA were highest in heifers fed soybeans held 3 h postroasting. In trial 2, 44 Holstein heifers weighing 150 to 250 kg were assigned randomly to one of four TMR. Diets consisted of 91.8% alfalfa silage and 7.5% of one of four soybean treatments. Treatments were raw soybeans, soybeans roasted in a drum roaster with an exit temperature of 146 degrees C, and those roasted with exit temperatures of 141 or 146 degrees C and held for .5 h. Estimated postruminal available lysine was higher for soybeans roasted and held versus roasted or raw soybeans. However, BW gain for heifers was similar across diets, averaging .90 kg/d for 12 wk. Concentrations of AA in plasma were not affected by diet. Overall, results support the recommendation of holding soybeans for at least .5 h following roasting.

Present study was conducted to investigate the optimal feeding levels for producing the high quality meat on the basis of the information deriving from the comparison of the growth performance and carcass characteristics among breeds (Holstein vs F1, Holstein♀ × Hanwoo ), sex ♂ (steer vs heifer) and interaction between breed and sex. Thirty two animals on 4 treatments (i.e. eight head each) were used for 540 days from seven to 24 months of age.The results obtained are summarized as follows; the range of average daily gains was 0.733 to 1.018, 0.994 to 1.255, 0.947 to 1.259 and 0.736 to 0.824 kg for the growing, the early-fattening, the midfattening and the finishing periods, respectively. The range of average daily gains for the entire period was 0.882 to 1.061 kg. The gains were higher for Holstein(7.3%) and the steers(10.5%) than F1 and the heifers, respectively. Concentrates and total digestible nutrients intakes per kg gain were higher for Holstein and the heifers than F1 and the steers, respectively. These findings may indicate that feed utilization is higher for Holstein than F1, and higher for the steers than the heifers.In carcass characteristics, back fat thickness was thicker for Holstein than F1, and rib-eye area was smaller for Holstein than F1. The rib-eye area per kg carcass weight was larger for F1 and the heifers than Holstein and the steers, respectively. Meat color was better for Holstein than F1, but the sex distinction did not show any differences. In physicochemical properties of longissimus dorsi, shear force, cooking loss, water holding capacity and the panel test scores of juiciness, tenderness and flavor for F1 and the heifers were better than those for Holstein and the steers, respectively. According to the above results, we may conclude that F1 and heifers rather than Holstein and steers are recommended for high quality meat production. In steers and heifers of Holstein and F1, the optimal feeding levels may be 1.9% of apparent body weight for concentrates and 25% of concentrates intake for rice straw.

Whole cotton seed (WCS) has become one of the major feed ingredients in TMR for dairy cattle in Korea, and WCS for feed use is mostly imported from abroad. Since this genetically modified oil seed is usually fed to the animal in raw state, its germination ability, if last long, often causes concerns about ecological disturbances. In the process of looking for effective conditions to remove germination ability of WCS this study had the objectives to evaluate the nutritional effects of gamma irradiation at doses of 8, 10 and 12 kGy on changes in nutrient contents, anti-nutritional factors, in vitro digestibility and ruminal degradability. No significant differences were found in proximate analysis of nutrients between raw WCS and gamma irradiated one. Glycine and threonine contents significantly increased when the WCS was exposed to gamma ray as compared to untreated WCS (p<0.05). As for fatty acid composition, no significant differences were observed with the irradiation treatment. Free gossypol in WCS was decreased (p<0.05) by gamma irradiation treatment. Of the 3 different levels of gamma irradiation, a dose of 12 kGy was found to be the most effective in reducing free gossypol concentration. Results obtained from in situ experiment indicated that gamma irradiation at a dose of 10 kGy significantly (p<0.05) lowered rumen degradability of both dry matter and crude protein as compared with raw WCS. However, there were no significant differences in rapidly degradable and potentially degradable fractions of crude protein due to 10 kGy gamma irradiation. Overall, this study show that gamma irradiation at a dose of 10 kGy is the optimum condition for removing germination ability of WCS, and could improve nutritive value for the ruminant with respect to the decrease in both ruminal protein degradability and gossypol content of WCS.

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