No abstract

A feeding trial using 12 Holstein bull calves (21±3 d) was conducted to investigate the effect of different processed maize grain and full fat soyabean included in the starter diets on their rumen fermentation and development. Three treatment starter diets contained different processed maize grain and soyabean: steam-fl aked maize and soyabean (SFMS), extruded maize and soyabean (EMS), and ground maize and raw soyabean (GMS). During 10-week trial, total rumen VFA concentration tended to be infl uenced by different processing methods at wk 6 and 9 (P<0.10). The molar proportion of butyrate for calves receiving SFMS starter diets was higher than that of EMS and GMS starter diets (P<0.05) at wk 5 and 11. Rumen papillae development characteristics expressed by papilla length, papilla width and rumen wall thickness were remarkably different among treatment starter diets (P<0.05).

This study aimed to evaluate the effects of steam-flaked corn grains and soybeans on muscle fatty acid composition. Thirty Holstein bull calves (21 ± 3 d) were divided into 3 groups according to birth date and BW and were randomly assigned to receive fresh milk and a commercial pelleted starter diet containing extruded corn and soybean (ECS), steam-flaked corn and soybean (SFCS), or ground corn and raw soybean (GCS). The calves were fed the designated diet from 3 to 13 wk of age, after which they were slaughtered. The supraspinatus (CTM), longissimus lumborum (RLM), and spinalis dorsi (ERM) were analyzed to determine the chemical and intramuscular fatty acid composition. The fatty acid composition of muscle and its deposition differed among calves fed different starter feeds. Medium-chain fatty acid levels of the RLM and CTM were greater in GCS-fed calves than in ECS- and SFCS-fed calves ( < 0.05). Extruded processing increased the content of linoleic, linolenic, and arachidonic acids of the RLM ( < 0.05). The palmitoleic and -vaccenic acid content of the ERM were greater in GCS-fed calves than in ECS- or SFCS-fed calves ( < 0.05). No significant differences were observed among the 3 diets with respect to the stearic, oleic, linoleic, -9 -11 CLA, or arachidonic acid content of the ERM ( > 0.05). The levels of -3 and -6 fatty acids were similar among the 3 groups; a lower -6:-3 PUFA ratio was observed in GCS-fed calves ( < 0.05). The cereal processing method of the calf starter feed had no significant effect on the chemical composition of the CTM, RLM, or ERM. Therefore, different methods of processing corn and soybean in calf starter feeds had no effect on the chemical composition of the RLM, CTM, or ERM but had a significant effect on the intramuscular fatty acid composition.