Yong-Suk Son

Effects of Gamma Irradiation on Nutrient Composition, Anti-nutritional Factors, In vitro Digestibility and Ruminal Degradation of Whole Cotton Seed

Whole cotton seed (WCS) has become one of the major feed ingredients in TMR for dairy cattle in Korea, and WCS for feed use is mostly imported from abroad. Since this genetically modified oil seed is usually fed to the animal in raw state, its germination ability, if last long, often causes concerns about ecological disturbances. In the process of looking for effective conditions to remove germination ability of WCS this study had the objectives to evaluate the nutritional effects of gamma irradiation at doses of 8, 10 and 12 kGy on changes in nutrient contents, anti-nutritional factors, in vitro digestibility and ruminal degradability. No significant differences were found in proximate analysis of nutrients between raw WCS and gamma irradiated one. Glycine and threonine contents significantly increased when the WCS was exposed to gamma ray as compared to untreated WCS (p<0.05). As for fatty acid composition, no significant differences were observed with the irradiation treatment. Free gossypol in WCS was decreased (p<0.05) by gamma irradiation treatment. Of the 3 different levels of gamma irradiation, a dose of 12 kGy was found to be the most effective in reducing free gossypol concentration. Results obtained from in situ experiment indicated that gamma irradiation at a dose of 10 kGy significantly (p<0.05) lowered rumen degradability of both dry matter and crude protein as compared with raw WCS. However, there were no significant differences in rapidly degradable and potentially degradable fractions of crude protein due to 10 kGy gamma irradiation. Overall, this study show that gamma irradiation at a dose of 10 kGy is the optimum condition for removing germination ability of WCS, and could improve nutritive value for the ruminant with respect to the decrease in both ruminal protein degradability and gossypol content of WCS.

A Nutritional Evaluation on Whole Cottonseed Removed Germination Ability by Heat-treatment

National Institute of Animal Science, RDA, Suwon 441-706, KoreaABSTRACTIn Korea, wide spread use of whole cottonseed, which is primarily a GMO plant imported from foreign countries and being fed to animals as raw state, has aroused concern that it may disturb the existing ecology of the country unless dispersion of the seed is under proper control. The objective of this study was to elucidate the changes in various nutritive parameters due to heat treatment and to determine the effective condition for removing germination ability of whole cottonseed(WCS). Of the various temperatures applied(76, 78, 80, 85, 100°C/30 min) 85°C for 30 min was confirmed to be the lowest temperature treatment which resulted in a complete removal of the germination ability of WCS. Therefore, based on the determined temperature condition(85°C 30min) we tried to examine the changes of various nutritional parameters, including nutrient composition, in vitro digestibilities and ruminal protein degradabilities, comparing raw whole cotton seed(RWCS) and heated whole cotton seed (HWCS). Some changes in amino acid composition were observed with heat treatment of WCS, but these were regarded to originate from the variation in plant quality and seed morphology, which are usually affected by different environmental factors during the vegetation period. As for fatty acid composition, no significant differences were observed to occur during heat treatment. However, WCS heated at 85°C for 30 min in a circulating oven showed a significant decrease(p<0.05) of in situ rumen degradability in both dry matter(DM) and crude protein(CP), as compared to raw WCS. Overall results obtained in the study indicate that the heating condition used in this study, which was proven to be the most appropriate and economic to remove germination ability of WCS, may also improve the nutritional value of the ruminant with regard to reducing its protein degradability within the rumen.(Key words :Whole cottonseed, Germination ability, Heat treatment, Degradability)

Study on Comparison of Growth Performance, Feed Efficiency and Carcass Characteristics for Holstein and F1(Holstein ♀ x Hanwoo ♂) Steers and Heifers

S. W. Kang*, Y. K. Oh*, K. H. Kim*, C. W. Choi* and Y. S. Son**National Livestock Research Institute, R.D.A.*,College of Life & Environmental Sciences, Korea University**ABSTRACTPresent study was conducted to investigate the optimal feeding levels for producing the high qualitymeat on the basis of the information deriving from the comparison of the growth performance and carcasscharacteristics among breeds(Holstein vs F1, Holstein ♀×Hanwoo ), sex♂ (steer vs heifer) and interactionbetween breed and sex. Thirty two animals on 4 treatments(i.e. eight head each) were used for 540 daysfrom seven to 24 months of age.The results obtained are summarized as follows; the range of average daily gains was 0.733 to 1.018,0.994 to 1.255, 0.947 to 1.259 and 0.736 to 0.824kg for the growing, the early-fattening, the mid-fattening and the finishing periods, respectively. The range of average daily gains for the entire period was0.882 to 1.061kg. The gains were higher for Holstein(7.3%) and the steers(10.5%) than F1 and theheifers, respectively. Concentrates and total digestible nutrients intakes per kg gain were higher for Holsteinand the heifers than F1 and the steers, respectively. These findings may indicate that feed utilization ishigher for Holstein than F1, and higher for the steers than the heifers.In carcass characteristics, back fat thickness was thicker for Holstein than F1, and rib-eye area wassmaller for Holstein than F1. The rib-eye area per kg carcass weight was larger for F1 and the heifersthan Holstein and the steers, respectively. Meat color was better for Holstein than F1, but the sexdistinction did not show any differences. In physicochemical properties of longissimus dorsi, shear force,cooking loss, water holding capacity and the panel test scores of juiciness, tenderness and flavor for F1and the heifers were better than those for Holstein and the steers, respectively.According to the above results, we may conclude that F1 and heifers rather than Holstein and steers arerecommended for high quality meat production. In steers and heifers of Holstein and F1, the optimalfeeding levels may be 1.9% of apparent body weight for concentrates and 25% of concentrates intake forrice straw.(Keywords : Holstein, F1, Steers, Heifers, Growth, Carcass Characteristics)Corresponding author:S. W. Kang, National Livestock Research Institute, R. D. A., Omokchun-dong, Kwonsun-gu, Suwon-Si, Kyeongki-do, 441-350, Korea. Tel:031-290-1641, Fax:031-290-1660,E-mail:swkang@rda.go.kr.

Effects of Feeding Type of Concentrates During Growing Period and Slaughter Age on Growth Performance, Feed Efficiency and Carcass Characteristics in Growing-Fattening Holstein Steers

The objectives of this work was to investigate the effects of feeding type of concentrates during growing pe- riod and slaughter age on growth performance, feed efficiency and carcass characteristics in growing-fattening Holstein steers. Treatments were two concentrates feeding types(ad libitum or restricted 1.9 % of BW) and three slaughter ages(at 19, 22 or 25 mo). Body weight at slaughter was numerically higher(approx. 8.3 %) for the restricted than the ad libitum feeding groups. TDN intake rate was higher(8.4 %) for the restricted than the ad libitum feeding groups. One mo slaughter delay increased TDN intake by 4%. Despite the lack of significances, higher back fat thickness and rib-eye area appeared in the restricted feeding or the late slaughter groups compared with the ad libitum feed- ing or the early slaughter groups. Marbling score(mean 2.46) numerically increased when the steers were re- strictively fed concentrates compared with the ad libitum feeding groups. In addition, significant increases in the marbling score were associated with the slaughter age delay. In economic analysis, increases in total in- come were associated with the restricted feeding and the slaughter age delay. Whereas the highest monthly in- come appeared in the restricted feeding-and-slaughter at 22 mo group. In conclusion, the optimal feeding system may be 1) the restricted concentrates feeding(1.9 % of BW) during growing period and 2) the late slaughter age(22 ~ 25 mo of age) in growing-fattening Holstein steers fed rice straw.