Dietary effects of protected fat, glycerol, and soybean meal on performance, physiological parameters, carcass characteristics, and behavioral measurements of late-fattening Hanwoo steers under heat stress conditions.

OBJECTIVE: This study aimed to determine the effects of increasing energy and protein levels in diets by including protected fat (PF), glycerol (GL), and soybean meal (SBM) on growth performance, physiological parameters, carcass characteristics, and behavioral measurements of late-fattening Hanwoo steers under heat stress conditions. METHODS: Thirty-six steers (initial body weight, 724.9±58.3 kg; age, 25.5±0.4 month) were assigned into control (total digestible nutrient [TDN] 76%, crude protein [CP] 15%), PF (TDN 83.6%, CP 15%), PF+GL (TDN 83.6%, CP 15%) and PF+GL+SBM (TDN 83.6%, CP 16.5%) by randomized complete block design for a total of 16 weeks with division of 4-week periods. The average temperature-humidity index was 87.0 (1st period; severe), 82.8 (2nd; moderate), 71.4 (3rd; comfort), and 68.1 (4th; comfort). RESULTS: The dry matter intake (DMI) showed no treatments differences during the whole experiment. However, DMI in 1st and 2nd period decreased by approximately 30% and 10% compared to 4th period, respectively. Higher average daily gain and feed conversion ratio were noted for treatments compared to control at both 1st and 2nd period (p<0.05). There were no treatment effects on rectal temperature (RT), cortisol, and behaviors during the entire experiment. However, both RT and cortisol in 0, 1st and 2nd period were higher than those of 3rd and 4th period (p<0.05). Carcass yield and grade remained unaffected by increasing TDN and CP levels. Behavioral changes in the hot season (1st period) included reduced lying (43%), increased standing (48%), decreased walking (62%), and decreased eating (38%) (p<0.05), with an increase in drinking by 54%. Rumination during standing was 53% higher, while rumination during lying was about 33% lower compared to the post-hot season (3rd period) (p<0.05). CONCLUSION: Dietary supplementation of protected fat in late-fattening Hanwoo steers under heat stress had a positive effect on preventing a reduction in performance.

Effects of heat stress on performance, physiological parameters, and blood profiles of early-fattening Hanwoo steers in climate chambers.

OBJECTIVE: This study was conducted to assess effects of heat stress on growth performance, physiological parameters, and blood profiles of Hanwoo steers during early-fattening period in climate chambers. METHODS: Four Hanwoo steers (body weight, 454.3±10.9 kg; age, 14±0.1 month) were allocated into four levels of temperature-humidity index (THI) in a 4×4 Latin square design for 21 days (pre-adaptation, 7 d; heat stress, 7 d; post-adaptation, 7 d) per period. Experimental treatments were assigned according to THI chart based on National Institute Animal Science (NIAS, 2022): Comfort (25.5°C to 26.5°C, 60%; THI 73 to 75), Mild (28°C to 29°C, 60%; THI 77 to 79), Moderate (29.5°C to 30.5°C, 80%; THI 82 to 84), and Severe (31°C to 32°C, 80%; THI 85 to 86) in separate climatic controlled chambers. RESULTS: The dry matter intake (DMI) of the formula feed was lower in Severe compared to Mild and Comfort (p<0.05). The DMI of rice straw was the lowest in Severe and lower in Moderate than Comfort and Mild (p<0.05). Both average daily gain and feed conversion ratio of Severe and Moderate were lower than those of Mild and Comfort (p<0.05). Water intake was the highest in Severe and lower in Moderate compared with Comfort and Mild (p<0.05). Heart rate and rectal temperature increased as THI level increased (p<0.05). Glucose was the lowest in Severe and lower in Moderate compared to Comfort (p<0.05). On the contrary, non-esterified fatty acid was the highest in Severe and lower in Moderate compared with Comfort (p<0.05). Blood urea nitrogen of Moderate and Severe were higher than those of Comfort and Mild (p<0.05). Cortisol increased as THI increased (p<0.05). CONCLUSION: This study demonstrated the negative effects of heat stress on the performance and physiological responses of Hanwoo steers during the early-fattening period. In addition, it is judged that the THI chart for Hanwoo steers of National Institute of Animal Science (2022) was properly calculated.

Spatio-temporal accumulation and sources of anthropogenic Pb in Ulleung Basin sediments, East/Japan Sea, based on stable Pb isotope ratios.

The accumulation, pathways, and sources of anthropogenic lead (Pb) in Ulleung Basin sediments were investigated based on the temporal and spatial variations in the Pb concentration and stable Pb isotopes for 21 dated box core sediments collected from the shelf, slope, and basin in the southern East/Japan Sea. Leached (1 M HCl) Pb concentrations and isotope ratios (207Pb/206Pb and 208Pb/206Pb) were nearly constant before 1930, but have increased rapidly until the present. The primary source of anthropogenic Pb is considered to be atmospheric deposition, showing the signature of a mixture of leaded gasoline and coals, which was the major anthropogenic source in the basin. However, after the 1990s, anthropogenic Pb from dumping materials added as much as 10-25% to the slope sediment and has been spreading out from the water column accompanied by the movement of the East Sea Intermediate Water. In shelf areas, inputs from nonferrous refineries in the coastal industrial complexes play an important role in pollution from anthropogenic Pb.

Prediction of total digestible nutrient and crude protein requirements according to daily weight gain, and behavioral measurements of Hanwoo heifers.

OBJECTIVE: This study was conducted to investigate the effects of energy and protein levels in the diet of Hanwoo heifers on growth response and animal behavior. METHODS: Forty heifers were randomly allocated into three experimental groups according to the target daily weight gain in 8 pens (T-0.2, 2 replications; T-0.4 and -0.6, 3 replications) based on similar body weight (BW) and age in months. The target average daily gain (ADG) was set at 0.2 (T-0.2), 0.4 (T-0.4), and 0.6 kg/d (T-0.6), and feed was based on National Institute of Animal Science (NIAS, 2017). In order to minimize hunger stress of T-0.2 and -0.4, the feeding ratio of rice straw was set to 55%, 50%, and 45% for T-0.2, -0.4 and T-0.6, respectively, so that the dry matter (DM) intake for all treatment groups was uniform but the energy and protein levels in the diet were adjusted differently. A total of 6 items (lying, standing, eating, rumination, walking and drinking) of animal behavior were analyzed. RESULTS: During the whole period of the experiment, the ADG of the T-0.2, -0.4 and -0.6 treatments were 0.48, 0.56, and 0.65 kg/d (p<0.05), respectively, showing higher gain than the predicted value, especially for the low target ADG group. Based on these results, regression equations for the total digestible nutrient (TDN) and crude protein (CP) requirements were derived. No behavioral differences were found according to the energy and protein levels in the diet because the DM intake was kept constant by adjusting the roughage and concentration ratio. However, eating time was longer (p<0.05) at T-0.2 than T-0.6 during the whole day. CONCLUSION: Through this study, it was possible to derive regression equations for predicting TDN and CP requirements according to the target ADG and BW.

Nutritional value and in situ degradability of fruit-vegetable byproducts and their feeding effects on performance of growing Hanwoo steers.

OBJECTIVE: This study was conducted to evaluate nutritional value and in situ degradability of fruit-vegetable byproducts and their feeding effects on performance of growing Hanwoo steers. METHODS: Nutritional value and in situ degradability of cabbage, Chinese cabbage and fruit-vegetable byproducts were assessed. In vivo feeding trial was also performed for 12 weeks. Thirty-six growing steers were randomly allocated into three groups according to body weight (BW) and age in 12 pens (4 replications/treatment) and assigned to one of the three dietary treatments: control (byproduct 0%), FV-B (fruit-vegetable byproduct 20%), and CA-B (cabbage peel 15% plus Chinese cabbage peel 15%, total byproduct 30%). RESULTS: The crude protein contents of cabbage, Chinese cabbage and fruit-vegetable byproducts were 18.69%, 20.20%, and 10.07%, respectively. Concentrations of neutral detergent fiber (NDF) were higher in cabbage (22.31%) and Chinese cabbage (28.83%) than fruit-vegetable (13.94%). Higher concentrations of non-fiber carbohydrate were observed for fruit-vegetable (66.72%) than cabbage (44.93%) and Chinese cabbage byproducts (24.69%). The effective degradability (ED) of both dry matter (DM) and NDF for fruit-vegetable byproduct (DM, 84.69%; NDF, 85.62%) was higher (p<0.05) than cabbage (DM, 68.47%; NDF, 55.97%) and Chinese cabbage byproducts (DM, 68.09%; NDF, 54.22%). The DM intake was not different among treatments because the amount of feed was kept constant according to the BW of growing steers to prevent overweight during the growing period. The average daily gain during the whole experimental period was not different among treatments (1.26, 1.25, and 1.34 kg/d for control, FV-B, and CA-B). The ED of both DM and NDF degradability of the total mixed ration (TMR) diets were very similar among treatments. Feed conversion ratio during the whole period showed no significant difference among treatments. CONCLUSION: This study demonstrates that fruit-vegetable and cabbage byproducts up to 20% and 30% (as fed basis), respectively can be included in TMR diets for growing beef cattle.