Yong-Joo Seol

Effect of Grain Sources on the Ruminal Methane Production in Hanwoo Steers

Department of Animal Science, Gyeongsang National University, KoreaABSTRACTThis study was conducted to investigate the effects of grain sources on the ruminal methane production in Hanwoo steers. Six Hanwoo steers(BW = 614.4 ± 8.3kg) were fed, on a DM basis(TDN 6.91kg), 10% rice straw and 90% barley or corn based concentrate, respectively, according to Korean Feeding Standards(Hanwoo). Each period lasted 18 days including a 14-day adaptation and a 4-day measuring period. The steers were in the ventilated hood-type respiration chamber system(one cattle per chamber) during each measuring period to measure heat and methane production for 1 day. Nutrient intake and digestibility were not affected by steer fed grain sources. Methane concentration was not affected by steer fed either barley or corn-based concentrate, respectively(0.022% vs. 0.025%). Methane production was greater by steers fed corn than those fed barley(119.3 g/day vs. 139.4g/day). This result indicated that methane emission factor by maintenance energy requirement for the late fattening Hanwoo fed corn was higher than the steers fed barley(43.6kg/head/year) vs. corn(50.9kg/head/year). Methane conversion rate (Ym) was 0.04 Ym and 0.05 Ym for barley and corn, respectively. (Key words :Barley, Corn, Methane)

Productivity and energy partition of late lactation dairy cows during heat exposure.

Three late-lactation Holstein cows were used to determine the effects of environmental temperature on performance and energy partitioning. Each cow was housed in a respiratory chamber for 30 consecutive days and exposed to three different conditions of environmental temperature: (i) 20 degrees C and 20 degrees C (20 degrees C), (ii) 25 degrees C and 20 degrees C (25 degrees C), (iii) 30 degrees C and 25 degrees C (30 degrees C) during the day and night, respectively. The temperature was switched in an interval of 10 days. Humidity in the chamber was maintained at 55-65% through the entire experimental period. The daily mean as well as morning and evening rectal temperatures of Holstein cows increased linearly (P < 0.05) as chamber temperature increased. There was a significant linear reduction in dry matter (DM) intake (P < 0.05) and an increase in DM digestibility (P < 0.05). The response in milk yield, however, was not affected by heat stress. There were no significant differences among treatments for intake energy, heat production, net energy for lactation and net energy for gain. This results of this study disagreed with the assumption that late lactation cows gave priority to increasing body tissue at the expense of milk production under thermal stress.

Effects of Different Levels of CP Intake on Protein Utilization and N Excretion in Varying Growth Stages of Hanwoo Steers

Three experiments with different stage of Hanwoo steers (average BW of 167 kg, 355 kg and 449 kg, respectively) were conducted to examine the effect of different quantities of CP intake with similar DM intake on protein balance and N excretion. Twelve Hanwoo steers in each experiment were offered three diets containing three levels of protein (9, 14 and 18 % on DM basis) in the concentrate formulated with using different amount of ground corn grain or corn gluten meal. There were significant effects of increasing CP intake on CP digestibility but not on DM digestibility. Despite different CP intake, apparent fecal N outputs were not significantly affected. However, amounts of N excreted into urine increased (p<0.05) with increasing CP intake. There was an obvious effect of live body weight on efficiency of body protein conversion of CP consumed in excess of animal requirement for maintenance, with slopes of 70 % and 46 ~ 39 % for growing and fattening stage, respectively. Nitrogen excretion into feces and urine in this experiment was 70 % of the daily N consumption for fattening stage, compared with 60 % for growing stage. (Key weeds : CP intake, Growth stages, Hanwoo steers, N excretion)

Effects of Thymol, Eugenol and Malate on In vitro Rumen Microbial Fermentation

The purpose of this study was to investigate effects of increased levels of eugenol, thymol and malate on pH and the concentrations of VFA, lactate and ammonia-N during in vitro ruminal incubation. One Hanwoo beef steer (741 kg) fitted with a rumen cannula was used and fed 0.5 kg/day rice straw and 10 kg/day corn-based concentrate (ratio of concentrate to rice straw = 95 : 5 on DM basis). Three different doses of thymol, eugenol and malate were used. Treatments of the experiment were as follows: Treatments of thymol were control (1g D-glucose/40ml), T1 (1g D-glucose + 40 mg thymol/40 ml), T2 (1g D-glucose + 50 mg thymol/40 ml) and T3 (1g D-glucose + 60 mg thymol/40 ml). Treatments of eugenol were control (1g D-glucose/40 ml), E1 (1g D-glucose + 55 mg eugenol/40 ml), E2 (1g D-glucose + 65 mg eugenol/40 ml) and E3 (1g D-glucose + 75 mg eugenol/40 ml). Treatments of malate were control (1g D-glucose/40ml), M1 (1g D-glucose + 25 mg malate/40ml), M2 (1g D-glucose + 50 mg malate/40 ml) and M3 (1g D-glucose + 100 mg malate/40 ml). The results of this study showed that eugenol and thymol have improved stability of the ruminal fermentation by decreasing lactic acid concentration and increasing ruminal pH. However, it inhibited the production of total VFA, acetate and propionate. Malate also improved stability of the ruminal fermentation by decreasing lactic acid concentration and increasing ruminal pH, but it had a very little effect on ruminal lactate concentrations and pH. On the other hand, malate did not decrease the concentrations of total VFA, acetate and propionate. Therefore, at the low ruminal pH expected in high-concentrate diets, thymol, eugenol, and malate are potentially useful in Hanwoo finishing diets. Further studies are necessary for determining the effectiveness of these additives on in vivo rumen fermentation and animal performance in Hanwoo finishing steers.

Effects of Caprylic Acid and Cyclodextrin Complex on In vitro Fermentation Characteristics and Methane Production

This study was conducted to evaluate the effects of dietary addition of caprylic acid(CA)-cyclodextrin (CD) complex on in vitro fermentation characteristics, total gas and methane production. Experiment was done with six treatment groups; 1) no CA-CD complex(control), 2) CA 20 mg(T1), 3) CD 830 mg(T2), 4) CA-CD complex 425 mg(T3), CA-CD complex 850mg(T4), CA-CD complex 1,700 mg(T5). Ruminal pH, ammonia and total VFA concentrations of T2, T3, T4 and T5 were lower(P

Determination of Crude Protein Requirements for Maintenance of Prepubertal Hanwoo Heifers

Two trials at different body weights of Hanwoo heifers (average body weight of 143 and 257 kg, respectively) were conducted to determine crude protein requirements for maintenance (CPm). Six Hanwoo heifers in each trial were used in two 3 3 Latin square design with three diets containing three levels of CP, 14 days in each period. In trial 1, the diets were based on 2.8 kg fresh wt./day/heifer timothy hay (LCP) with supplements of either 250 g ground corn and 150 g corn gluten meal (MCP) or 500 g ground corn and 300 g corn gluten meal (HCP). In trial 2, the diets were based on 4.8 kg fresh wt./day/heifer timothy hay (LCP) with supplements of either 350 g ground corn and 250 g corn gluten meal (MCP) or 700 g ground corn and 500 g corn gluten meal (HCP). In trial 1, CP intakes were 236.6, 340.1, and 459.8 g/d for LCP, MCP, and HCP, respectively. Crude protein balances were 0.51, 1.87 and 3.20g//d for LCP, MCP, and HCP, respectively. In trial 2, CP intakes were 415.2, 606.9 and 793.0g/d for LCP, MCP and HCP, respectively. Crude protein balances were 0.67, 1.03, 2.99 g//d for LCP, MCP, and HCP, respectively. The maintenance requirements for CP from the regression equation between CP intake and CP balance were 4.58g//d (trial 1) and 5.02 g//d (trial 2) and lower than the value (5.56 g//d) adopted by Korean Feeding Standards for Hanwoo (2007).

Determination of Maintenance Energy Requirements for Growing Hanwoo Steers

Present experiment was carried out to determine maintenance energy requirements for growing Hanwoo steers. Six Hanwoo steers (BW = kg) were used in two 3 3 latin square design with three different energy intake levels; TDN 1.70 kg (Low), 2.05 kg (Medium), 2.80 kg (High), respectively, based on the Korean Feeding Standards. Each period lasted 18 days including a 14-day adaptation and a 4-day measuring period. The steers were in the head hood chamber system (one cattle per chamber) during each measuring time to measure heat and methane production for 1 day. Dry matter intake was 2,058, 3,256 and 3,881 g/day for Low, Medium and High TDN, respectively. Increase in energy intake did not affect digestibilities of dry matter, crude protein, crude fiber, crude fat, NDF, ADF and nitrogen-free extract. Gross energy intake averaged 180.21, 292.74 and 337.15 kcal/ for Low, Medium and High TDN, respectively. Energy loss was 28.7% in feces and 2.1% in urine of gross energy intake. Further, energy loss from methane produced during rumen fermentation was 6~8.3%, while body heat loss averaged 34~60%. Intercept of regression equation between ME intake and retained energy indicated that the energy requirement was 109.84 kcal ME/.

Effects of a Mixture of Eugenol, Thymol and Malate on Growth Performance, Beef Quality and Liver Function in Hanwoo Finishing Steers Fed a High-Concentrate Diet

ABSTRACT Thirty six Hanwoo steers (average BW, 564.5± 25.7 kg; average age, approximately 23 months) were used to evaluate the effects of a mixture of eugenol (14%), thymol (1%) and malate (85%) on growth performance, beef quality and liver function in Hanwoo finishing steers fed ahigh-concentrate diet. A feeding trial was conducted for 7 months in National Agricultural Cooperative Federation farm located in Anseong, Korea. Steers were assigned randomly to one of three treatments: control (without additive supplementation), treatment 1 (0.05% additive of concentrate), treatment 2 (0.1% additiveof concentrate). The results of this study showed that initial and final BW averaged 564 and 755 kg, respectively, and BW gain was significantly higher (P<0.05) for steers fed the additive mixture than for those fed no mixture (0.78 and 0.79 vs. 0.69 kg/d, respectively). Serum aspartate aminotransferase in the T2 treatment was decreased during the 24 to 31 months of age. Although supplementation of additives resulted in no substantial effect on carcass characteristics, it had a potential effect to improve feed efficiency and AST concentration in Hanwoo finishing steers fed a high-concentrate diet. In conclusion, a mixture of eugenol, thymol and malate has shown promise in improving feed efficiency and liver function in the finishing phase of Hanwoo steers.(

Effects of Sodium Bicarbonate and Vitamin Supplementation on Milk Production and Composition in Lactating Holstein Cows Under Heat Stress Condition

Sixteen multiparous lactating Holstein cows were used to compare effects of supplementing 1) no additive (Control), 2) 1.2% sodium bicarbonate (NaHCO3); 3) niacin (80 g/d), 4) vitamin A+E (140,000 IU + 1000 IU) on feed intake, milk production, milk composition and somatic cell counts during the summer months. Insofar as possible, treatment groups were balanced for lactation number and days in milk. Cows were fed a diet of 9.1 kg DM of concentrate and 10.2 kg DM of corn silage. Daily maximum air temperature in free stall barn was 35 for 3 days of the pretreatment periods and decreased gradually up to 27 during the treatment periods of 15days. Dry matter intake of corn silage was higher (p<0.05) for cows consuming NaHCO3 than those not consuming NaHCO3. Daily milk production for niacin and vitamin A+E supplementations resulted in significant (p<0.001) increase in milk production from 3 day of trials than control and NaHCO3. Milk fat percentage tended (p=0.09) to increase and milk lactose percentage was increased significantly (p<0.001) for cows supplemented with NaHCO3, niacin and vitamin A+E. Milk protein percentages was higher significantly (p<0.05) with supplemental niacin and somatic cell counts was higher significantly (p<0.001) with supplemental vitamin A+E. These data strongly suggest that supplementation of NaHCO3, niacin or vitamin A+E should be increased for improving milk production and mammary gland health of dairy cows under heat stress.