Effect of Rumen-Protected L-Tryptophan or L-Ascorbic Acid on Plasma Metabolites and Milk Production Characteristics of Lactating Holstein Cows during Summer Conditions.

This study investigated the effects of rumen-protected L-tryptophan or L-ascorbic acid supplementation on the productivity of lactating Holstein cows during a high-temperature period. Thirty cows were assigned to three dietary groups: control (CON), treatment 1 (TRT 1; rumen-protected L-tryptophan, 20 g/cow/d), and treatment 2 (TRT 2; rumen-protected L-ascorbic acid, 20 g/cow/d). As the high-temperature period progressed, the decrease in milk yield and dry matter intake (DMI) in the TRT 1 and TRT 2 groups was lower than that in the CON group. The total protein level in the plasma of the TRT 1 group was higher than that in the CON group (p < 0.05). Milk melatonin concentration was higher in the TRT 1 group than in the CON and TRT 2 groups (p < 0.05). Thus, the present results indicate that rumen-protected L-tryptophan or L-ascorbic acid has positive effects in preventing declines in DMI and milk yield by reducing heat stress in Holstein cows. In particular, rumen-protected L-tryptophan is considered effective in increasing the melatonin concentration in milk.

Effect of Lupin Supplementation on the Growth, Carcass, and Meat Characteristics of Late-Fattening Hanwoo Steers.

This study aimed to investigate the effects of lupin flake supplementation on the growth, plasma parameters, carcass characteristics, and meat composition of late-fattening Hanwoo steers. The steers (n = 40) were randomly divided into the four groups with 10 steers each: LP0 (lupin flake 0%), LP3 (lupin flake 3%), LP6 (lupin flake 6%), and LP9 (lupin flake 9%). The total digestible nutriant intake increased as the concentration of lupin increased (linear and quadratic effects; p < 0.05). The thiobarbituric acid-reactive substance content in the strip loins decreased as lupin flake supplementation levels increased (linear and quadratic effects; p < 0.05), while carnosine levels increased linearly (p < 0.05). As the lupin flake supplementation level increased, anserine and creatinine contents increased linearly and quadratically (p < 0.05). Similarly, adenosine triphosphate (ATP) and adenosine monophosphate (AMP) content increased with increasing lupin flake supplementation levels in linear and quadratic effects (p < 0.001). Palmitoleic acid content increased significantly with increasing lupin flake supplementation level (linear and quadratic effects; p < 0.05). The content of oleic acid in the strip loin was not significant, but the unsaturated fatty acid (UFA) (p < 0.05) and n-6/n-3 ratio (p < 0.05) increased. The results of this study indicated that although lupin flake supplementation did not markedly affect the growth, carcass characteristics, or meat composition of late-fattening Hanwoo steers, it exerted a positive effect on the flavor, taste profiles (anserine, creatinine, ATP, and AMP), hypotonicity (TBARS), and healthy meat production (UFA and n-6/n-3 ratio) related to beef.

Intramuscular fat formation in fetuses and the effect of increased protein intake during pregnancy in Hanwoo cattle.

Understanding adipocyte development in fetus during bovine pregnancy is important for strengthening fattening technology. Additionally, nutritional level of dams during pregnancy has the potential to improve offspring growth and fat development. The purpose of this study is to evaluate the intramuscular adipocyte development and expression level of related genes in bovine fetus, and the effect of increased crude protein (CP) intake during pregnancy on the growth performance and carcass characteristics of male offspring. Eighty six pregnant Hanwoo cows (average body weight, 551.5 ± 51.3 kg, age 5.29 ± 0.61 y) were used. Fetuses were collected at 90, 180 and 270 d of gestation from 18 pregnant Hanwoo cows. The remaining 68 pregnant cows were randomly assigned to 2 feeding groups. The control (CON) group was provided the standard protein diet (n = 34), and treatment (TRT) group was provided a diet with a 5% increase in CP intake (n = 34). Male offspring were divided into two groups according to protein treatment of the pregnant cows: CON male offspring (CON-O) and TRT male offspring (TRT-O). Intramuscular adipocytes were found in the fetal skeletal muscle after 180 days of gestation. Male calf's birth weight increased in the TRT group compared to that in the CON group (p < 0.002). The final body weight (p < 0.003) and average daily gain (p < 0.019) of male offspring were significantly higher in TRT-O than in CON-O. The feed conversion ratio was also improved by 10.5% in TRT-O compared to that in CON-O (p < 0.026). Carcass weight was significantly higher in the TRT-O group than that in the CON-O group (p < 0.003), and back fat was thicker in the TRT-O group (p = 0.07). The gross receipts and net income were higher in TRT-O than in CON-O (p < 0.04). Thus, fetal intramuscular fat can be formed from the mid-gestation period, and increased CP intake during pregnancy can increase net income by improving the growth and carcass weight of male offspring rather than intramuscular fat.

Effect of Rumen Protected Methionine and α-Tocopherol on Growth Performance, Carcass Characteristics, and Meat Composition of Late Fattening Hanwoo Steer in High-Temperature Seasons.

This study was conducted to investigate the effects of rumen-protected methionine and α-tocopherol (RPMT) on growth performance, carcass characteristics, and meat composition of late fattening Hanwoo steers in high-temperature seasons. Fourteen steers were randomly assigned to one of two diets; control (commercial concentrate) and treatment (commercial concentrate + 20 g of RPMT). Average daily gain was 34% higher in the treatment group than in the control group; however, there was no significant difference due to the small number under investigation. Feed conversion ratio was lower in the treatment group than in the control group (p < 0.05). Supplementation of RPMT had little effect on the fatty acid composition of longissimus muscle. Metmyoglobin in the longissimus muscle was significantly lower in treatment group compared to the control group at the ninth day of storage (p < 0.05). The redness of the longissimus muscle was higher in the treatment group than in the control group on day 9 of storage (p < 0.01). Thus, the results suggest that RPMT have positive effects on growth performance, and Commission Internationale de l'Eclairage color stability in the longissimus muscle of late fattening Hanwoo steers in high-temperature seasons.

A study on the optimal thickness of corn flakes produced by using the pressurized steam chamber.

This study was conducted to evaluate the effect of the thickness of corn flakes produced by pressurized steam chamber (PSC) on rumen fermentation characteristics and nutrient degradability in Hanwoo and Holstein cows. Corn flakes were treated by PSC, in three groups based on corn flake thickness: < 2.5 mm (T1), 2.5-3.0 mm (T2), and > 3.0 mm (T3). Corn flake thickness significantly influenced pH (p < 0.01) and propionate concentration (p < 0.05) and slightly but not significantly influenced acetate, butyrate, and total-volatile fatty acids (T-VFA) concentrations. The dry matter (DM) degradability increased significantly with a reduction in corn flake thickness (p < 0.01), being significantly greater in T1 and T2 than T3 groups (p < 0.01) and similar between T1 and T2 groups throughout whole incubation time. Also, starch degradability was the lowest in T3 groups than others (p < 0.01). Thus, the present results showed that considering the production efficiency and economic feasibility, the optimal thickness of corn flakes produced in a PSC is recommended to be 2.5-3.0 mm.

Effect of Total Digestible Nutrients Level of Concentrates on Growth Performance, Carcass Characteristics, and Meat Composition of Korean Hanwoo Steers.

This study was conducted to investigate the effect of the total digestible nutrients (TDN) level of commercial concentrates on growth performance, carcass characteristics, and meat composition of late fattening Hanwoo steers. A total of 28 steers were randomly assigned to one of four dietary groups; T1 (73.30% TDN), T2 (74.50% TDN), T3 (76.40% TDN), and T4 (77.10% TDN). Average daily gain (ADG) was slightly but not significantly higher in the T2 than in the other treatments. Dry matter intake (DMI) and feed conversion ratio (FCR) were higher in the T2 than in the other treatments; however, the differences were not statistically significant. Carcass back fat thickness was thicker in the T4 and marbling score was higher in the T2 than in the other treatments; however, the differences were not statistically significant. The TDN level of concentrates had no effect on the physicochemical characteristics and fatty acid composition of the longissimus muscle. The finding of this study indicate that less than 74% or greater than 75% TDN in the commercial concentrate did not contribute to improve ADG, FCR, marbling score; therefore, in the present study, the recommendable TDN level in the commercial concentrate for late fattening period was 74% to 75% in terms of growth performance and marbling score of Hanwoo steer.

A study on comparative feeding value of corn flakes according to temperature and retention time in the pressurized steam chamber.

This study aimed to investigate the effects of temperature and retention time of the pressurized steam chamber on the ruminal fermentation characteristics and nutrient degradability of corn flakes in three Korean native Hanwoo cows and three Holstein cows implanted with a ruminal fistula. Corn kernels were categorized into 13 groups based on the chamber temperature (range, 100°C-116°C) and retention time (range, 700-950 s). The pH value was lowest in T1 regardless of breed. Propionate concentration was the highest in T2 (p < 0.05). Total-volatile fatty acid (VFA) concentration was slightly but not significantly greater in T2 than in other conditions. Dry matter (p < 0.05), starch, and crude protein (p < 0.05) degradability were the highest in T1. At different incubation times and with different breeds, dry matter, starch, and crude protein degradability of corn flakes were the highest in T1. Thus, the present results indicate that the optimal temperature and retention time of the pressurized steam chamber should be 100°C-105°C and 700-720 s.

Effects of dietary levels of tapioca residue on growth performance and carcass characteristics in Hanwoo steers.

OBJECTIVE: This study was conducted to investigate the effects of dietary levels of tapioca residue on growth performance, carcass characteristics, and meat composition in Hanwoo steers. METHODS: Twenty-eight steers were randomly assigned to one of four dietary groups; T0 (0% tapioca residue), T6.7 (6.7% tapioca residue), T9 (9% tapioca residue), and T12 (12% tapioca residue). RESULTS: Supplementation with tapioca residue had no effect on overall growth performance. The concentration of plasma total cholesterol was higher in T6.7 than in other treatments (p<0.05). Dietary levels of tapioca residue did not affect carcass yield or the quality traits of Hanwoo steers. The lightness, redness, and yellowness of the longissimus muscle of Hanwoo steers were higher in T6.7 than in other treatments (p<0.05). Cohesiveness, gumminess, chewiness, and resilience were lower in T6.7 than in other treatments (p<0.05). CONCLUSION: The results of the present study indicate that supplementation with tapioca residue does not exert any negative effects on growth performance, carcass characteristics, and meat composition in Hanwoo steers. However, as the dietary level of tapioca residue increased, the intake of concentrate intake decreased, and tapioca supplementation greater than 6.7% did not substantially improved the marbling score.

Effects of weaning and castration ages on growth performance, blood metabolites, and carcass characteristics in Hanwoo steers.

BACKGROUND: Recently, as production costs have been increasing owing to rising feed prices worldwide, shortening the age of slaughter has been recognized as a way to increase farm income. In Korea, the raising period for Hanwoo steers is over 31 months with the delay of weaning and castration stated as one of the reasons for the increase in the raising period. Thus far, studies on age of weaning and castration have been conducted individually, and there have been no studies on the combined effects of weaning and castration ages on the growth performance and carcass characteristics in Hanwoo steers. METHODS: Weaning ages were calculated at 80 or 130 days of age, and castration ages were calculated at 90 days and 180 days of age. Calves were allocated to one of the four treatment groups: W80C90 (weaning at 80 days of age and castration at 90 days of age), W80C180, W130C90, and W130C180. RESULTS: For the entire experimental period, weaning and castration ages did not significantly affect growth performance of Hanwoo steers. In addition, weaning and castration ages did not affect the overall yield and quality traits of carcass in Hanwoo steers. CONCLUSION: Weaning and castration ages had small effects on growth performance and carcass characteristics in Hanwoo steers. Therefore, the early weaning and castration ages are recommended to reduce the slaughter age without any negative effects on meat quality grade.