• Asian-Australasian Journal of Animal Sciences
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• v.17 no.3
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• pp.330-336
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• 2004

Six 16 months old Holstein steers were offered ad libitum feed for 7 months, to determine the (1) relationships of backfat thickness (BFT) to plasma leptin, and insulin; and (2) associations of TDN intake/kg body weight (BW) to plasma leptin, BFT and insulin. Feed intake, body weight and BFT were measured on selected monthly ages from day 1 to 8, day 1 and 8, and day 8, respectively. Blood was sampled on day 8 and the plasma was analyzed for leptin, insulin, glucose, NEFA, total cholesterol and triglyceride. Body weight and BFT increased, while TDN intake per kg BW decreased from 16 to 23 months old. Plasma leptin increased and mimicked the level of insulin, resulting to significant correlation (r=0.54; p<0.002). TDN intake was negatively related to plasma leptin (r=0.49; p<0.004), insulin (r=0.41; p<0.02) and BFT at 12 to 13th rib (r=0.48; p<0.005). Backfat thickness at 12 to 13th rib was positively related to plasma leptin (r=0.45; p<0.01). Negative associations of TDN intake with plasma leptin and BFT during finishing period suggest long-term involvement of adipose tissues in the feed intake regulation of steers fed high concentrate diet.

• Journal of agriculture & life science
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• v.50 no.5
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• pp.153-162
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• 2016

This study was conducted to investigate a proper management and nutrient supply for raising replacement heifers to improve lactating performance. In order to determine a proper TDN/CP ratio that would be suitable for domestic use, 13-month-old replacement heifers were fed in the ratios of 4.6:1(T1) and 4.3:1(T2), respectively, to examine the changes in nutritional intake, digestibility, characteristics of rumen fluid and blood compositions. While dry matter intake was same at 9.0kg/day, CP intake did not show any significant difference, though T2(1.45kg/day) was slightly higher than T1(1.34kg/day). In fiber intake and digestibility, two results showed no significant difference, though T1 was slightly higher than T2. The pH, NH3-N and VFA densities in rumen fluid examined at the fourth hour after feed intake did not show any significant difference either. Overall level of VFA was not influenced largely by the TDN/CP ratio, but the iso-butyrate and iso-valerate levels and the A/P ratio were significantly high in T1(p<0.05). In blood characteristics, the treatments showed no significant difference. In conclusion, the TDN/CP ratios of 4.3:1 and 4.6:1 did not significantly affect the characteristics of the ruminant stomach, but in comparison with digestibility of 13-month-old heifers, the ratio of 4.6:1 was more appropriate for increased intake of fiber and higher digestibility.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.2
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• pp.271-274
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• 1993

Four Holstein heifers were used in the present study to investigate the effect of standing and lying behaviors on heat production and physiological responses under low (L), medium (M) and high (H) levels of TDN intake. Rectal temperature (RT), respiration rate (RR), heart rate (HR), heat production (HP) and animals behavior (standing time, ST) were measured continuously for 5h (11:00-16:00) periods. There was a tendency for increased RT with TDN intake, and no difference in RT was observed between standing and lying. The RR, HR and HP during standing were significantly higher (p<0.05) than during lying. The difference between standing and lying HP were 4.41, 4.68 and $5.37kJ/kg^{0.75}$ h for L, M and H of TDN intake, respectively. These values showed that standing HP was 18.6-20.9% higher than lying HP. A multiple regression analysis of HP ($kJ/kg^{0.75}$ h) on TDN intake ($g/kg^{0.75}$ d) and ST (min/h) was HP = 7.75 + 0.28 TDN intake + 0.12 ST (R = 0.84). This analysis showed that the total HP not only depend on feed intake levels, but also depends on animal behavior. It was suggested that the change in HP due to the change in feed intake and animal behavior would influence the level of heat loss which was indicated by the changes in the RR and HR.

• Journal of Animal Science and Technology
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• v.47 no.3
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• pp.447-456
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• 2005

This study was conducted to evaluate the effects of energy level of concentrate feed in finishing Hanwoo steers for 6 months before slaughter. Feeding trial was done with 2 treatment groups, IDN72 (72% of TDN in concentrate) and TDN74 (74 % of TDN in concentrate). The body weight (from 19 to 24 months) tended to be higher in TDN74 than in TDN72, but was not significant. Average daily gain of TDN74 was higher by 4.4 % in comparison to TDN72. There was no significant differences in concentrate, dry matter and TDN intake per I kg body weight gain between TDN72 and TDN74. And there was a tendency to improve crude protein intake per I kg body weight gain by increasing TDN content from 72 to 74 %. The dressing percentage tended to be higher in TDN74 than in TDN72, but was not significant. Salable meat percentage tended to be lower in TDN74 than in TDN72 because of higher body fat percentage in TDN74 than in TDN72. There were no significant differences in marbling score, meat color, fat color, carcass weight, rib-eye area and back fat thickness between TDN72 and TDN74. Significant differences were not found in shear value, cooking loss, water holding capacity or moisture and protein contents of longissimus dorsi (LD) muscles between TDN72 and TDN74. Fat content of LD muscles tend to be lower in TDN74 than in IDN72 but without any significance. There was a tendency to improve juiciness and taste by feeding IDN74 rather than TDN72. Especially, tenderness of TDN74 was increased by 7.4% in comparison to TDN72 (p < 0.05). Gross income from TDN74 was higher than TDN72 by 5% The results suggested that significant differences were not found in growth performance, feed conversion and carcass characteristics between TDN72 and TDN74. The results also show that more studies are required to clarify the energy level for finishing Hanwoo steers.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.5
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• pp.611-616
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• 2006

Genetic parameters for performance traits on 409 bulls and growth and carcass traits on 591 of their steer progeny were estimated in Japanese Black cattle with Gibbs sampling. Traits of bulls included body weight at the start (BWS) and finish (BWF) of test, daily gain (DG), concentrate, roughage and TDN intake, and TDN conversion ratio. Progeny traits were BWS, BWF, DG, rib eye area, marbling score (MSR), dressing percentage and subcutaneous fat thickness (SFT). In bulls, heritabilities were high for BWS (0.50) and BWF (0.63) and moderate for concentrate (0.48) and TDN intake (0.45), while in progeny, the heritability for all the studied traits was moderate to high (ranging from 0.30 to 0.73), highlighting the potential for genetic improvement of these traits. Genetic correlations between TDN intake and growth traits (BWS, BWF and DG) in bulls were highly positive (ranging from 0.77 to 0.94). The weak but negative genetic correlation (-0.20) between MSR and SFT in progeny indicated that improvement of beef marbling without increasing subcutaneous fat deposition could be possible. The estimated genetic correlations of roughage intake of bulls with body weights (BWS and BWF) and MSR of their progeny were moderate (ranging from 0.35 to 0.52). On the basis of the selection for bulls, growth traits and TDN intake correlated positively with SFT (ranging from 0.43 to 0.53) of their progeny, suggesting the necessity of controlling the increase of SFT in selection programs.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.5
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• pp.701-709
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• 2001

Yeso sika deer (Cervus nippon yesoensis) grazed on various types of plants, and the fiber content in these plants was low. The tastes of yeso sika deer for existing feeds for ruminant livestock resembled those of sheep. Though the digestibility of these feeds in yeso sika deer was slightly lower than that in sheep, the nutritive values of DCP and TDN were similar between the two species, suggesting that feed for sheep can be utilized. Therefore, in small-scale farming of yeso sika deer, the feeding amount in feeding planning can be determined using the feeding standards for sheep. However, when concentrates are fed, correction of TDN is necessary. In large-scale pasturage, the nutritional intake in summer is adequate because yeso sika deer graze on various types of wild plants. In winter, they mainly graze on sasa (Sasa senanensis), and supplementary food may be necessary to supply TDN. Thus, since yeso sika deer graze on many types of wild plants, existing feeds for ruminant livestock can be used. In addition, plant biomasses except concentrates that do not cause competition with existing livestock may be effectively utilized in yeso sika deer, suggesting their importance as animal resources. The data on the intake and nutritive values of Sasa senanensis can be parameters for estimating the appropriate inhabitant number of wild yeso sika deer in wintering areas.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.1
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• pp.91-97
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• 1993

This experiment was carried out to examine the effects of urea-treated rice straw feeding on the growth performance of crossbred Holstein heifers under different feeding conditions. In the first experiment, the animals were given diets having 2 levels of TDN and CP and 3 levels of crude fiber (22, 30 and 36%) which were formulated with urea-treated rice straw and concentrates. Daily weight gain of heifers was not different between 22% and 30% CF diets, but the reduction of TDN or CP level to 90% of the requirements decreased the weight gain. Fiber content of 36% also reduced the body weight gain. The reduction of TDN significantly reduced DM intake and increased feed conversion ratio. Feed cost per kg weight gain was significantly increased by an increase in CF to 36%. In the second experiment, separate feeding and total mixing feeding were compared. There were no significant differences between the two feeding systems in body weight gain although the possibility of superiority in SF to TMF remained. DM intake was not affected by the feeding system, but 30% CF diet gave higher DM intake. Feed cost per kg weight gain was lower in the 30% CF diet.

• Journal of The Korean Society of Grassland and Forage Science
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• v.36 no.2
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• pp.115-123
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• 2016

In this study, the effect of energy and protein ratio on the nutrient availability and body weight gain was determined to find the proper nutrient level for the stage of replacement dairy heifers before fertilization at approximately 12~24 months old after birth. Dry matter intake showed that the TDN/CP rate of T1 (5.0:1), T2 (4.5:1) and T3 (4.0:1) resulted in similar values. Among feces, the ash content of T1 was 11.07%, which was significantly (p < 0.05) higher than that of T3 (9.69%). It was also significantly (p < 0.05) higher than that of T2 (10.32%). When the TDN/CP rate was increased, the ash content in the feces was also increased. Regardless of the initial weight, weight gain was increased significantly as the CP rate in the feed was increased on the $30^{th}$ day. On the $60^{th}$ day, T2 showed the highest rate of gain (p < 0.05). As the TDN rate was decreased or the protein rate was increased, weight gain was significantly (p < 0.05) increased. Regarding GPT level in the blood after finishing the test, T1 and T3 (112.6, 88.3 u/l) showed significantly (p < 0.05) higher value than T2 (50.9 u/l). For phosphorus level, T1 (46.3 mg/dl) showed significantly (p < 0.05) higher value than other treatments. For HDL cholesterol level, T2 (145.2 mg/dl) had significantly (p < 0.05) higher level than T1 (121.0 mg/dl) or T3 (132.3 mg/dl). For triglyceride levels, T3 (40.6 mg/dl) had significantly (p < 0.05) higher value than T1 (20.7 mg/dl) and T2 (29.0 mg/dl). For other blood parameters including BUN concentration, there were no significant (p > 0.05) difference among treatments. As a result, although feed intake and weight gain with TDN/CP rate of 4:1 showed best results, considering the excess body fat accumulation possibilities or blood metabolism, it seems 4.5:1 ratio is most appropriate.

• Korean Journal of Agricultural Science
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• v.45 no.1
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• pp.74-83
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• 2018

Four early-fattening Hanwoo steers weighing $247{\pm}13.5kg$ were used within a $4{\times}4$ Latin square design to establish a nutrient requirement for maintenance and to investigate nutritional changes in the steers under heat stress condition. The steers were fed four different energy level diets: 100% (control) and 100%, 115% and 130% of total digestible nutrients (TDN) requirement of the early-fattening Hanwoo steers for maintenance based on the Korean Feeding Standard for Hanwoo. The steers in the control were housed with no stress (temperature $24^{\circ}C$ and humidity 60%), whereas the steers in the other groups were under heat stress (temperature $30^{\circ}C$ and humidity 70%). True digestibilities of dry matter (DM) and other nutrients were not significantly (p > 0.05) affected by heat stress (i.e., control vs T100). This may be the result of a lower DM intake than that of the Korean feeding standard due to the establishment of the nutrients requirement under heat stress. Heat stress and different energy intake levels did not affect the blood metabolite concentrations. Average daily gain (ADG) for T100 (-69.6 g) was lower than that of the control (-44.6 g, numerically), T115 (44.6 g, p < 0.05) and T130 (83.3 g, p < 0.05), respectively. Based on the ADG and TDN intake, the equation (Y = 0.1814X + 111.5) for the TDN requirement of the early fattening Hanwoo steers for maintenance was calculated, indicating that 11.5% of TDN requirement for maintenance under heat stress may be additionally supplied.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.3
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• pp.269-276
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• 2009

This experiment was carried out to investigate the effects of increases of nutrient level of TMR on dry matter intake, digestibility, nitrogen and energy balance in growing dairy goats (Saanen). Twelve growing dairy goats weighing 17.5kg were randomly assigned to one of four TMRs; low energy-low crude protein (CP) TMR (control; A), high energy-low CP TMR (B), low energy-high CP TMR (C) and high energy-high CP TMR (D). The content of total digestible nutrients (TDN) and CP in the control diet were 67% and 11%. The TDN content of the high energy TMR was 73.7% and the CP content of the high CP TMR was 13%. Dry matter intake was highest in D, and significantly higher in B than in C (p<0.05). Digestibility for dry matter and cell contents increased in proportion to dry matter intake. NDF digestibility was higher in D than in A, while ADF digestibility was higher in A and C than in B, but was not significant. Digestible nitrogen, apparently digested nitrogen and retained nitrogen were correlated with intake, and significantly higher in B than in C (p<0.05). Digestible energy and metabolizable energy were highest in D, and significantly higher in B than in C (p<0.05). Therefore, the present results showed that D or B were better than C for high intake, digestibility, nitrogen and energy utilization.