Studies on digestive physiology of rearing calves fed total mixed rations | Verdauungsphysiologische Untersuchungen zum Einsatzt von Totalmischrationen für aufzuchtkälber
2008
Van Ackeren, K., Hohenheim Univ., Stuttgart (Deutschland). Institut für Tierernährung | Steingass, H. | Drochner, W.
To ensure a well developed forestomach and a sufficient growth rate, in rearing calves concentrate (C) diets are provided because dry matter intake (DMI) and short-chain fatty acid production are higher than with diets based only on roughage. However, feeding diets contai-ning large amounts of highly digestible carbohydrates or lacking an adequate level of effec-tive fibre can lead to subacute ruminal acidosis. Determining the optimal level of forage is ne-cessary to develop the rumen properly and stabilize ruminal fermentation patterns in young calves. Hence TMR feeding is discussed in ad libitum-fed calves to avoid an excessive C intake. Due to the low DMI of young calves with ad libitum roughage feeding and to optimize acceptance a TMR (referred as dry TMR) based on dry ingredients is recommended. In this study, 15 rumen-cannulated (wk 6) early-weaned (E-W: 8 wk milk-fed) male Holstein calves were randomly assigned to three treatments and observed from wk 8 to 15. Three TMRs con-sisting of 15, 30 or 40% chopped hay (H) were compared concerning their effects on growth performance and ruminal fermentation patterns. Water, TMR and hay were offered ad libitum twice daily. Ruminal fluid was collected via cannula at wk 9, 11, 13 and 15, twice weekly (-1h and 1, 3, 5, 7h after the a.m. meal). In summary, feeding a dry TMR consisting of 30-40% H to E-W calves is recommendable for different reasons: DMI increased rapidly as calves aged, ensuring an adequate fibre supply, achieving sufficient growth rate and physiological ruminal fermentation patterns, resulting in a successful calf raising.
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