Feeding strategies with total mixed ration and concentrate may improve feed intake and carcass quality of Hanwoo steers

Effects of high-protein concentrates with different rumen undegradable-to-degradable protein ratios on performance and carcass traits in 26-month-slaughtered Hanwoo steers

OBJECTIVE

This study investigated the effects of high-protein concentrates with two different rumen undegradable protein (RUP)-to-degradable protein ratios on the performance and carcass characteristics of Hanwoo steers reared for 26 months.

METHODS

Thirty-two Hanwoo steers (217±13 kg) were randomly allocated to eight pens (four animals/pen) and assigned to one of two concentrate treatments (four pens/treatment), low-RUP concentrate (LRUP; RUP ratio of 37:63) or high-RUP concentrate (HRUP; RUP ratio of 47:53), with a dietary crude protein (CP) content of 20% dry matter (DM) during the growing stage (8 to 17 months) and 18% DM during the fattening stage (18 to 26 months).

RESULTS

Increasing the RUP ratio in the concentrate reduced (p = 0.062) rumen ammonia (NH3-N) levels during the growing stage. A decrease (p<0.05) in the molar proportions of acetate and valerate, and an increase (p = 0.097) in the proportions of iso-valerate, was observed in the HRUP group. Significant improvements (p<0.05) in the average daily gain and the feed conversion ratio were observed in the HRUP group during the fattening stage. Although there were no significant group differences in carcass yield or characteristics in steers slaughtered at 26 months, a trend (p = 0.081) toward an increased rib-eye area was observed in the HRUP group. Relative mRNA expression profiling revealed higher lipid biosynthesis and lipolysis in the HRUP group at slaughter. However, no effects on intramuscular fat content was detected.

CONCLUSION

Raising the RUP level improved performance and intramuscular fat metabolism in Hanwoo steers. The final body weight of the steers in the HRUP group was comparable to that of Hanwoo steers raised under the conventional 30-month fattening period. Overall, feeding a high-CP concentrate with a higher RUP proportion (47% CP) may be a beneficial strategy to shorten the feeding period.

Unmixed Diet Versus Total Mixed Ration in Beef Cattle Fed High-Concentrate Diets: Effects on Methane Emissions, Animal Performance, and Rumen Fermentation

This study assessed the effects of using a total mixed ration (TMR), compared to distributing the concentrate and the forage separately, on the productive performance of beef cattle fed high-concentrate diets and on rumen fermentation characteristics, including methane production. Eighteen rumen-fistulated beef calves were fed a concentrate plus pelleted barley straw separately (CS; n = 9) or as TMR (n = 9). Average daily gain and intake of TMR and of straw and concentrate with the CS treatment were recorded. Digestibility was estimated using ashes insoluble in hydrochloric acid as a marker. Rumen liquid and gas samples were obtained, and the abundance of total bacteria, methanogens, protozoa, and anaerobic fungi was analysed. Animals were slaughtered at 500 kg live weight (LW), and dressing percentage and carcass classification were obtained. Another 49 animals for each treatment were used on a commercial farm to exclusively assess animal performance. The treatment (CS or TMR) did not significantly affect (p > 0.05) final LW, average daily gain, carcass dressing percentage, dry matter or digestible organic matter intake, digestibility values, production of methane and carbon dioxide, and abundance of microorganisms in the rumen. However, animals fed TMR had lower rumen pH (5.87 vs. 5.58, p = 0.041 for CS and TMR), suggesting a higher risk of experiencing rumen acidosis than those fed straw and concentrate separately. In conclusion, using a total mixed ration does not seem a suitable strategy to reduce methane production or prevent rumen acidosis in feedlot cattle.

Effects of different feeding systems on ruminal fermentation, digestibility, methane emissions, and microbiota of Hanwoo steers

This study evaluates how different feeding systems impact ruminal fermentation, methane production, and microbiota of Hanwoo steers native to Korea. In a replicated 2 × 2 crossover design over 29 days per period, eight Hanwoo steers (507.1 ± 67.4 kg) were fed twice daily using a separate feeding (SF) system comprising separate concentrate mix and forage or total mixed rations (TMR) in a 15:85 ratio. The TMR-feeding group exhibited a considerable neutral detergent fiber digestibility increase than the SF group. However, ruminal fermentation parameters and methane production did not differ between two feeding strategies. In addition, TMR-fed steers expressed elevated Prevotellaceae family, Christensenellaceae R-7 group, and an unidentified Veillonellaceae family genus abundance in their rumen, whereas SF-fed steers were rich in the Rikenellaceae RC9 gut group, Erysipelotrichaceae UCG-004, and Succinivibrio. Through linear regression modeling, positive correlations were observed between the Shannon Diversity Index and the SF group's dry matter intake and methane production. Although feeding systems do not affect methane production, they can alter ruminal microbes. These results may guide future feeding system investigations or ruminal microbiota manipulations as a methane-mitigation practice examining different feed ingredients.

Effects of Concentrate Feeding Sequence on Growth Performance, Nutrient Digestibility, VFA Production, and Fecal Microbiota of Weaned Donkeys

In this study, effects on the growth performance, nutrient digestibility, volatile fatty acids (VFA) production, and fecal microbiota of weaned donkeys were observed using different concentrate feeding sequences. Fifteen healthy 6-month-old weaned male donkeys with a body weight of 117.13 ± 10.60 kg were randomly divided into three treatment groups, including group C1 (roughage-then-concentrate), group C2 (concentrate-then-roughage), and group C3 (total mixed ration, TMR). The experiment lasted 35 d. We measured nutrient digestion by the acid-insoluble ash method and analyzed the fecal microbiota of the weaned donkeys by high-throughput sequencing of 16s rRNA genes in the V3-V4 region. The results show that group C3 obtained the best growth performance, and the digestibility of crude protein (CP) and crude extract (EE) was significantly higher than that of group C1 (p < 0.05). Acetic acid, isobutyric acid, valeric acid, isovaleric acid, and caproic acid were notably different among all groups (p < 0.05). In addition, we observed that Firmicutes and Bacteroidetes were dominant in the fecal microbes of each group, and Firmicutes was significantly higher in group C3 (p < 0.05). At the genus level, the different genera were Treponema, Rikenellaceae-RC9-gut-group, Unidentified-F082, and Bacteroidales-RF16-group (p < 0.05). The prediction of fecal microbiota function by PICRUSt indicated that different feeding sequences had minimal impact on the function of the fecal microbiota, particularly on the high-abundance pathway. In summary, the concentrate feeding sequence changed the composition of the fecal microbe of weaned donkeys.

A Comparative Study on the Adipogenic and Myogenic Capacity of Muscle Satellite Cells, and Meat Quality Characteristics between Hanwoo and Vietnamese Yellow Steers

Myogenesis and adipogenesis are the important processes determining the muscle growth and fat accumulation livestock, which ultimately affecting their meat quality. Hanwoo is a popular breed and its meat has been exported to other countries. The objective of this study was to compare the myogenesis and adipogenesis properties in satellite cells, and meat quality between Hanwoo and Vietnamese yellow cattle (VYC). Same 28-months old Hanwoo (body weight: 728±45 kg) and VYC (body weight: 285±36 kg) steers (n=10 per breed) were used. Immediately after slaughter, tissue samples were collected from longissimus lumborum (LL) muscles for satellite cells isolation and assays. After 24 h post-mortem, LL muscles from left carcass sides were collected for meat quality analysis. Under the same in vitro culture condition, the proliferation rate was higher in Hanwoo compared to VYC (p<0.05). Fusion index was almost 3 times greater in Hanwoo (42.17%), compared with VYC (14.93%; p<0.05). The expressions of myogenesis (myogenic factor 5, myogenic differentiation 1, myogenin, and myogenic factor 6)- and adipogenesis (peroxisome proliferator-activated receptor gamma)-regulating genes, and triglyceride content were higher in Hanwoo, compared with VYC (p<0.05). Hanwoo beef had a higher intramuscular fat and total monounsaturated fatty acids contents than VYC beef (p<0.05). Whilst, VYC meat had a higher CIE a* and total polyunsaturated fatty acids content (p<0.05). Overall, there was a significant difference in the in vitro culture characteristics and genes expression of satellite cells, and meat quality between the Hanwoo and VYC.

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.

Evaluating feed value of native Jeju bamboo (Sasa quelpaertensis Nakai) for beef cattle

OBJECTIVE

Recently, indigenous Korean grass Sasa quelpaertensis Nakai (SQ) has garnered much interest as a roughage source for livestock to mitigate its adverse effects on habitat diversity. Thus, the objective of the present study was to evaluate the ruminal fermentation, palatability, and nutrient digestibility of SQ for Korean native beef cattle (Hanwoo) using in vitro rumen fermentation, in situ rumen degradability, and in vivo feeding trials.

METHODS

Using in vitro tests with rumen fluid as the inoculum for 48 h, ruminal fermentation of SQ was evaluated and compared with that of other roughage sources commonly used in Korea (i.e., rice straw, Timothy hay, and Italian ryegrass [IRG]). Additionally, an in situ trial 96 h was performed using three cannulated Hanwoo steers. Further, an in vivo trial was performed using eight Hanwoo steers to compare the palatability of SQ with rice straw in total mixed ration (TMR) and forage-concentrate separate feeding conditions. Finally, an in vivo digestibility trial of SQ fed as TMR of two particle sizes was performed with four Hanwoo steers.

RESULTS

In vitro and in situ trials revealed that SQ was comparable or superior to rice straw in terms of the ruminal fermentation characteristics of pH, gas production, total volatile fatty acid content, and effective ruminal dry matter digestibility (DMD), although its fermentability was lower than that of Timothy hay and IRG. In the palatability test, steers showed a greater preference for SQ when given as TMR. The total tract DMD of SQ fed as TMR was 75.9%±1.37%, and it did not differ by particle size.

CONCLUSION

The feed value of SQ as a roughage source for Hanwoo steers is comparable or superior to that of rice straw, particularly when provided as TMR.