Rumen bypass fat is commonly added to increase energy intake in dairy cattle. The objective of this study is to examine the addition of rumen bypass fat during finishing period on performance and carcass characteristics in grain fed steers. This study was conducted as a completely randomized block design with 126 cross-bred steer calves (initial BW 471.5 ± 7.5 kg) randomly assigned to pens with 9 steers/pen (n = 7 pens/treatment). Each pen was randomly assigned to one of two treatment groups; rumen bypass fat treatment (CCS, calcium soap of palm fatty acids) and control diet (CT, tallow). The diets were formulated to be isonitrogenous and isocaloric. Animals were fed twice daily at 110 % of the previous daily ad libitum intake. Blood from each sample was taken from the jugular vein. Muscle and adipose samples were collected from the longissimus dorsi regions. Feedlot performance and carcass characteristics were assessed. To examine adipogenic gene expression, quantitative real-time PCR was completed. Steers fed the CT had a greater level of performance for most of the parameters measured. The CT group had greater DMI (P < 0.05) and tended to have greater ADG (P < 0.10). Marbling score (P < 0.05) and quality grade (P < 0.05) were greater for steers fed the CT diet than those fed CCS. The longissimus muscle area tended to be greater (P < 0.10) in steers fed CT (87.60 cm2) than those fed CCS (84.88 cm2). The leptin mRNA expression was down-regulated (P < 0.05) in adipose tissue of steers fed a CCS when compared to those fed CT. These data suggest that calcium soap of palm fatty acids can be added to finishing diets without significant reduction in final body weight, although there may be modest reductions in marbling and quality scores.

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.

No abstract

In 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 30 min) 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.